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PIC18FXX20 Data Sheet
64/80-Pin High Performance, 1 Mbit Enhanced FLASH Microcontrollers with A/D
2003 Microchip Technology Inc.
Advance information
DS39609A
Note the following details of the code protection feature on Microchip devices: * * * Microchip products meet the specification contained in their particular Microchip Data Sheet. Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as "unbreakable."
* *
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break microchip's code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip's products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights.
Trademarks The Microchip name and logo, the Microchip logo, KEELOQ, MPLAB, PIC, PICmicro, PICSTART, PRO MATE and PowerSmart are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Accuron, dsPIC, dsPICDEM.net, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, PICC, PICkit, PICDEM, PICDEM.net, PowerCal, PowerInfo, PowerTool, rfPIC, Select Mode, SmartSensor, SmartShunt, SmartTel and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. (c) 2003, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 and Mountain View, California in March 2002. The Company's quality system processes and procedures are QS-9000 compliant for its PICmicro(R) 8-bit MCUs, KEELOQ(R) code hopping devices, Serial EEPROMs, microperipherals, non-volatile memory and analog products. In addition, Microchip's quality system for the design and manufacture of development systems is ISO 9001 certified.
DS39609A - page ii
2003 Microchip Technology Inc.
PIC18FXX20
64/80-Pin High Performance, 1 Mbit Enhanced FLASH Microcontrollers with A/D
High Performance RISC CPU:
* C compiler optimized architecture/instruction set: - Source code compatible with the PIC16 and PIC17 instruction sets * Linear program memory addressing to 128 Kbytes * Linear data memory addressing to 3840 bytes * 1 Kbyte of data EEPROM * Up to 10 MIPs operation: - DC - 40 MHz osc./clock input - 4 MHz - 10 MHz osc./clock input with PLL active * 16-bit wide instructions, 8-bit wide data path * Priority levels for interrupts * 31-level, software accessible hardware stack * 8 x 8 Single Cycle Hardware Multiplier
Analog Features:
* 10-bit, up to 16-channel Analog-to-Digital Converter (A/D): - Conversion available during SLEEP * Programmable 16-level Low Voltage Detection (LVD) module: - Supports interrupt on Low Voltage Detection * Programmable Brown-out Reset (PBOR) * Dual analog comparators: - Programmable input/output configuration
Special Microcontroller Features:
* 100,000 erase/write cycle Enhanced FLASH program memory typical * 1,000,000 erase/write cycle Data EEPROM memory typical * 1 second programming time * FLASH/Data EEPROM Retention: > 40 years * Self-reprogrammable under software control * Power-on Reset (POR), Power-up Timer (PWRT) and Oscillator Start-up Timer (OST) * Watchdog Timer (WDT) with its own On-Chip RC Oscillator for reliable operation * Programmable code protection * Power Saving SLEEP mode * Selectable oscillator options including: - 4X Phase Lock Loop (of primary oscillator) - Secondary Oscillator (32 kHz) clock input * In-Circuit Serial ProgrammingTM (ICSPTM) via two pins * MPLAB(R) In-Circuit Debug (ICD) via two pins
External Memory Interface (PIC18F8X20 Devices Only):
* Address capability of up to 2 Mbytes * 16-bit interface
Peripheral Features:
High current sink/source 25 mA/25 mA Four external interrupt pins Timer0 module: 8-bit/16-bit timer/counter Timer1 module: 16-bit timer/counter Timer2 module: 8-bit timer/counter Timer3 module: 16-bit timer/counter Timer4 module: 8-bit timer/counter Secondary oscillator clock option - Timer1/Timer3 Five Capture/Compare/PWM (CCP) modules: - Capture is 16-bit, max. resolution 6.25 ns (TCY/16) - Compare is 16-bit, max. resolution 100 ns (TCY) - PWM output: PWM resolution is 1- to 10-bit * Master Synchronous Serial Port (MSSP) module with two modes of operation: - 3-wire SPITM (supports all 4 SPI modes) - I2CTM Master and Slave mode * Two Addressable USART modules: - Supports RS-485 and RS-232 * Parallel Slave Port (PSP) module
Program Memory Device PIC18F6520 PIC18F6620 PIC18F6720 PIC18F8520 PIC18F8620 PIC18F8720 Bytes 32K 64K 128K 32K 64K 128K Data Memory I/O 52 52 52 68 68 68
* * * * * * * * *
CMOS Technology:
* * * * Low power, high speed FLASH technology Fully static design Wide operating voltage range (2.0V to 5.5V) Industrial and Extended temperature ranges
# Single Word SRAM EEPROM Instructions (bytes) (bytes) 16384 32768 65536 16384 32768 65536 2048 3840 3840 2048 3840 3840 1024 1024 1024 1024 1024 1024
10-bit A/D CCP (ch) (PWM) 12 12 12 16 16 16 5 5 5 5 5 5
MSSP SPI Y Y Y Y Y Y
Timers Master USART 8-bit/16-bit 2C I Y Y Y Y Y Y 2 2 2 2 2 2 2/3 2/3 2/3 2/3 2/3 2/3
Ext Bus N N N Y Y Y
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 1
PIC18FXX20
Pin Diagrams 64-pin TQFP
RE6 RE7/CCP2*
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
RD6/PSP6 RD7/PSP7
RE2/CS
RE3
RE4
RE5
VDD
VSS
RE1/WR RE0/RD RG0/CCP3 RG1/TX2/CK2 RG2/RX2/DT2 RG3/CCP4 MCLR/VPP RG4/CCP5 VSS VDD RF7/SS RF6/AN11 RF5/AN10/CVREF RF4/AN9 RF3/AN8 RF2/AN7/C1OUT
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33
RB0/INT0 RB1/INT1 RB2/INT2 RB3/INT3 RB4/KBI0 RB5/KBI1/PGM RB6/KBI2/PGC VSS OSC2/CLKO/RA6 OSC1/CLKI VDD RB7/KBI3/PGD RC5/SDO RC4/SDI/SDA RC3/SCK/SCL RC2/CCP1
PIC18F6520 PIC18F6620 PIC18F6720
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
RF1/AN6/C2OUT
RF0/AN5
* CCP2 is multiplexed with RC1 when CCP2MX is set.
DS39609A-page 2
Advance Information
RC0/T1OSO/T13CLK RC6/TX1/CK1 RC7/RX1/DT1 2003 Microchip Technology Inc.
RA4/T0CKI RC1/T1OSI/CCP2*
AVSS RA3/AN3/VREF+
RA2/AN2/VREF-
RA5/AN4/LVDIN
RA1/AN1
RA0/AN0
AVDD
VSS
VDD
PIC18FXX20
Pin Diagrams (Cont.'d) 80-pin TQFP
RH1/A17 RH0/A16 RE2/CS/AD10*** RE3/AD11 RE4/AD12 RE5/AD13 RE6/AD14 RE7/CCP2/AD15** RD0/PSP0/AD0*** VDD VSS RD1/PSP1/AD1*** RD2/PSP2/AD2*** RD3/PSP3/AD3*** RD4/PSP4/AD4*** RD5/PSP5/AD5*** RD6/PSP6/AD6*** RD7/PSP7/AD7*** RJ0/ALE RH2/A18 RH3/A19 ***RE1/WR/AD9 ***RE0/RD/AD8 RG0/CCP3 RG1/TX2/CK2 RG2/RX2/DT2 RG3/CCP4 MCLR/VPP RG4/CCP5 VSS VDD RF7/SS RF6/AN11 RF5/AN10/CVREF RF4/AN9 RF3/AN8 RF2/AN7/C1OUT RH7/AN15 RH6/AN14
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 RJ2/WRL RJ3/WRH RB0/INT0 RB1/INT1 RB2/INT2 RB3/INT3/CCP2* RB4/KBI0 RB5/KBI1/PGM RB6/KBI2/PGC VSS OSC2/CLKO/RA6 OSC1/CLKI VDD RB7/KBI3/PGD RC5/SDO RC4/SDI/SDA RC3/SCK/SCL RC2/CCP1 RJ7/UB RJ6/LB
PIC18F8520 PIC18F8620 PIC18F8720
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
* CCP2 is multiplexed with RC1 when CCP2MX is set. ** CCP2 is multiplexed by default with RE7 when the device is configured in Microcontroller mode. *** PSP is available only in Microcontroller mode.
2003 Microchip Technology Inc.
RH5/AN13 RH4/AN12 RF1/AN6/C2OUT RF0/AN5 AVDD AVSS RA3/AN3/VREF+ RA2/AN2/VREFRA1/AN1 RA0/AN0 VSS VDD RA5/AN4/LVDIN RA4/T0CKI RC1/T1OSI/CCP2* RC0/T1OSO/T13CLK RC6/TX1/CK1 RC7/RX1/DT1 RJ4/BA0 RJ5/CE
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RJ1/OE
DS39609A-page 3
PIC18FXX20
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 7 2.0 Oscillator Configurations ............................................................................................................................................................ 21 3.0 Reset .......................................................................................................................................................................................... 29 4.0 Memory Organization ................................................................................................................................................................. 39 5.0 FLASH Program Memory ........................................................................................................................................................... 61 6.0 External Memory Interface ......................................................................................................................................................... 71 7.0 Data EEPROM Memory ............................................................................................................................................................. 79 8.0 8 X 8 Hardware Multiplier ........................................................................................................................................................... 85 9.0 Interrupts .................................................................................................................................................................................... 87 10.0 I/O Ports ................................................................................................................................................................................... 103 11.0 Timer0 Module ......................................................................................................................................................................... 131 12.0 Timer1 Module ......................................................................................................................................................................... 135 13.0 Timer2 Module ......................................................................................................................................................................... 141 14.0 Timer3 Module ......................................................................................................................................................................... 143 15.0 Timer4 Module ......................................................................................................................................................................... 147 16.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 149 17.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 157 18.0 Addressable Universal Synchronous Asynchronous Receiver Transmitter (USART).............................................................. 197 19.0 10-bit Analog-to-Digital Converter (A/D) Module ...................................................................................................................... 213 20.0 Comparator Module.................................................................................................................................................................. 223 21.0 Comparator Voltage Reference Module ................................................................................................................................... 229 22.0 Low Voltage Detect .................................................................................................................................................................. 233 23.0 Special Features of the CPU .................................................................................................................................................... 239 24.0 Instruction Set Summary .......................................................................................................................................................... 259 25.0 Development Support............................................................................................................................................................... 301 26.0 Electrical Characteristics .......................................................................................................................................................... 307 27.0 DC and AC Characteristics Graphs and Tables ....................................................................................................................... 341 28.0 Packaging Information.............................................................................................................................................................. 343 Appendix A: Revision History............................................................................................................................................................. 347 Appendix B: Device Differences......................................................................................................................................................... 347 Appendix C: Conversion Considerations ........................................................................................................................................... 348 Appendix D: Migration from Mid-Range to Enhanced Devices .......................................................................................................... 348 Appendix E: Migration from High-End to Enhanced Devices............................................................................................................. 349 Index .................................................................................................................................................................................................. 351 On-Line Support................................................................................................................................................................................. 361 Systems Information and Upgrade Hot Line ...................................................................................................................................... 361 Reader Response .............................................................................................................................................................................. 362 PIC18FXX20 Product Identification System....................................................................................................................................... 363
DS39609A-page 4
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2003 Microchip Technology Inc.
PIC18FXX20
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and enhanced as new volumes and updates are introduced. If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via E-mail at docerrors@mail.microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We welcome your feedback.
Most Current Data Sheet
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Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of silicon and revision of document to which it applies. To determine if an errata sheet exists for a particular device, please check with one of the following: * Microchip's Worldwide Web site; http://www.microchip.com * Your local Microchip sales office (see last page) * The Microchip Corporate Literature Center; U.S. FAX: (480) 792-7277 When contacting a sales office or the literature center, please specify which device, revision of silicon and data sheet (include literature number) you are using.
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2003 Microchip Technology Inc.
Advance Information
DS39609A-page 5
PIC18FXX20
NOTES:
DS39609A-page 6
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2003 Microchip Technology Inc.
PIC18FXX20
1.0 DEVICE OVERVIEW
This document contains device specific information for the following devices: * PIC18F6520 * PIC18F6620 * PIC18F6720 * PIC18F8520 * PIC18F8620 * PIC18F8720 With the addition of new Operating modes, the External Memory Interface offers many new options, including: * Operating the microcontroller entirely from external memory * Using combinations of on-chip and external memory, up to the 2 Mbyte limit * Using external FLASH memory for reprogrammable application code, or large data tables * Using external RAM devices for storing large amounts of variable data
This family offers the advantages of all PIC18 microcontrollers - namely, high computational performance at an economical price - with the addition of high-endurance Enhanced FLASH program memory. The PIC18FXX20 family also provides an enhanced range of program memory options and versatile analog features that make it ideal for complex, high performance applications.
1.1.3
EASY MIGRATION
Regardless of the memory size, all devices share the same rich set of peripherals, allowing for a smooth migration path as applications grow and evolve. The consistent pinout scheme used throughout the entire family also aids in migrating to the next larger device. This is true when moving between the 64-pin members, between the 80-pin members, or even jumping from 64-pin to 80-pin devices.
1.1
1.1.1
Key Features
EXPANDED MEMORY
The PIC18FXX20 family introduces the widest range of on-chip, Enhanced FLASH program memory available on PICmicro(R) microcontrollers - up to 128 Kbyte (or 65,536 words), the largest ever offered by Microchip. For users with more modest code requirements, the family also includes members with 32 Kbyte or 64 KByte. Other memory features are: * Data RAM and Data EEPROM: The PIC18FXX20 family also provides plenty of room for application data. Depending on the device, either 2048 or 3840 bytes of data RAM are available. All devices have 1024 bytes of data EEPROM for long-term retention of non-volatile data. * Memory Endurance: The Enhanced FLASH cells for both program memory and data EEPROM are rated to last for many thousands of erase/write cycles - up to 100,000 for program memory, and 1,000,000 for EEPROM. Data retention without refresh is conservatively estimated to be greater than 40 years.
1.1.4
OTHER SPECIAL FEATURES
1.1.2
EXTERNAL MEMORY INTERFACE
In the unlikely event that 128 Kbyte of program memory is inadequate for an application, the PIC18F8X20 members of the family also implement an External Memory Interface. This allows the controller's internal program counter to address a memory space of up to 2 MByte, permitting a level of data access that few 8-bit devices can claim.
* Communications: The PIC18FXX20 family incorporates a range of serial communications peripherals, including 2 independent USARTs and a Master SSP module, capable of both SPI and I2C (Master and Slave) modes of operation. For PIC18F8X20 devices, one of the general purpose I/O ports can be reconfigured as an 8-bit Parallel Slave Port for direct processor-to-processor communications. * CCP Modules: All devices in the family incorporate 5 Capture/Compare/PWM modules to maximize flexibility in control applications. Up to four different time-bases may be used to perform several different operations at once. * Analog Features: All devices in the family feature 10-bit A/D converters, with up to 16 input channels, as well as the ability to perform conversions during SLEEP mode. Also included are dual analog comparators with programmable input and output configuration, a programmable Low Voltage Detect module, and a Programmable Brown-out Reset module. * Self-programmability: These devices can write to their own program memory spaces under internal software control. By using a bootloader routine located in the protected Boot Block at the top of program memory, it becomes possible to create an application that can update itself in the field.
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 7
PIC18FXX20
1.2 Details on Individual Family Members
3. 4. 5. A/D channels (12 for PIC18F6X20 devices, 16 for PIC18F8X20) I/O pins (52 on PIC18F6X20 devices, 68 on PIC18F8X20) External program memory interface (present only on PIC18F8X20 devices)
The PIC18FXX20 devices are available in 64-pin and 80-pin packages. They are differentiated from each other in five ways: 1. FLASH program memory (32 Kbytes for PIC18FX520 devices, 64 Kbytes for PIC18FX620 devices, and 128 Kbytes for PIC18FX720 devices) Data RAM (2048 bytes for PIC18FX520 devices, 3840 bytes for PIC18FX620 and PIC18FX720 devices)
All other features for devices in the PIC18FXX20 family are identical. These are summarized in Table 1-1. Block diagrams of the PIC18F6X20 and PIC18F8X20 devices are provided in Figure 1-1 and Figure 1-2, respectively. The pinouts for these device families are listed in Table 1-2.
2.
TABLE 1-1:
Features
PIC18FXX20 DEVICE FEATURES
PIC18F6520 DC - 40 MHz 32K 16384 2048 1024 No 17 Ports A, B, C, D, E, F, G 5 5 MSSP, Addressable USART (2) PSP 12 input channels PIC18F6620 DC - 25 MHz 64K 32768 3840 1024 No 17 PIC18F6720 DC - 25 MHz 128K 65536 3840 1024 No 17 PIC18F8520 DC - 40 MHz 32K 16384 2048 1024 Yes 18 Ports A, B, C, D, E, F, G, H, J 5 5 MSSP, Addressable USART (2) PSP 16 input channels PIC18F8620 DC - 25 MHz 64K 32768 3840 1024 Yes 18 Ports A, B, C, D, E, F, G, H, J 5 5 MSSP, Addressable USART (2) PSP 16 input channels PIC18F8720 DC - 25 MHz 128K 65536 3840 1024 Yes 18 Ports A, B, C, D, E, F, G, H, J 5 5 MSSP, Addressable USART (2) PSP 16 input channels
Operating Frequency Program Memory (Bytes) Program Memory (Instructions) Data Memory (Bytes) Data EEPROM Memory (Bytes) External Memory Interface Interrupt Sources I/O Ports Timers Capture/Compare/ PWM Modules Serial Communications
Ports A, B, C, D, Ports A, B, C, D, E, F, G E, F, G 5 5 MSSP, Addressable USART (2) PSP 12 input channels 5 5 MSSP, Addressable USART (2) PSP 12 input channels
Parallel Communications 10-bit Analog-to-Digital Module RESETS (and Delays)
POR, BOR, POR, BOR, RESET RESET Instruction, Instruction, Stack Full, Stack Full, Stack Underflow Stack Underflow (PWRT, OST) (PWRT, OST) Yes Yes 77 Instructions 64-pin TQFP Yes Yes 77 Instructions 64-pin TQFP
POR, BOR, POR, BOR, POR, BOR, POR, BOR, RESET RESET RESET RESET Instruction, Instruction, Instruction, Instruction, Stack Full, Stack Full, Stack Full, Stack Full, Stack Underflow Stack Underflow Stack Underflow Stack Underflow (PWRT, OST) (PWRT, OST) (PWRT, OST) (PWRT, OST) Yes Yes 77 Instructions 64-pin TQFP Yes Yes 77 Instructions 80-pin TQFP Yes Yes 77 Instructions 80-pin TQFP Yes Yes 77 Instructions 80-pin TQFP
Programmable Low Voltage Detect Programmable Brown-out Reset Instruction Set Package
DS39609A-page 8
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2003 Microchip Technology Inc.
PIC18FXX20
FIGURE 1-1: PIC18F6X20 BLOCK DIAGRAM
Data Bus<8>
PORTA RA0/AN0 RA1/AN1 RA2/AN2/VREFRA3/AN3/VREF+ RA4/T0CKI RA5/AN4/LVDIN RA6 PORTB RB0/INT0 RB1/INT1 RB2/INT2 RB3/INT3 RB4/KBI0 RB5/KBI1/PGM RB6/KBI2/PGC RB7/KBI3/PGD PORTC
21 21
Table Pointer<21> 8 inc/dec logic 8
Data Latch Data RAM Address Latch
21
PCLATU PCLATH
12 Address<12> 4
BSR
PCU PCH PCL Program Counter Address Latch Program Memory Data Latch
TABLELATCH
12 FSR0 FSR1 FSR2 inc/dec logic
4
Bank0, F
31 Level Stack
12
Decode
16
8
ROMLATCH
IR
RC0/T1OSO/T13CKI RC1/T1OSI/CCP2 RC2/CCP1 RC3/SCK/SCL RC4/SDI/SDA RC5/SDO RC6/TX1/CK1 RC7/RX1/DT1
8 PORTD PRODH PRODL Instruction Decode & Control Power-up Timer Timing Generation Oscillator Start-up Timer Power-on Reset Precision Bandgap Reference Watchdog Timer Brown-out Reset 8 x 8 Multiply 3 BITOP 8 WREG 8 8 ALU<8> 8 PORTF RF0/AN5 RF1/AN6/C2OUT RF2/AN7/C1OUT RF3/AN8 RF4/AN9 RF5/AN10/CVREF RF6/AN11 RF7/SS PORTG USART1 USART2 Data EEPROM 8 8 PORTE RE0/RD RE1/WR RE2/CS RE3 RE4 RE5 RE6 RE7 RD7/PSP7:RD0/PSP0
OSC2/CLKO OSC1/CLKI
MCLR
VDD, VSS
Synchronous Serial Port
RG0/CCP3 RG1/TX2/CK2 RG2/RX2/DT2 RG3/CCP4 RG4/CCP5
BOR LVD
Timer0
Timer1
Timer2
Timer3
Timer4
Comparator
CCP1
CCP2
CCP3
CCP4
CCP5
10-bit A/D
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 9
PIC18FXX20
FIGURE 1-2: PIC18F8X20 BLOCK DIAGRAM
Data Bus<8> PORTA RA0/AN0 RA1/AN1 RA2/AN2/VREFRA3/AN3/VREF+ RA4/T0CKI RA5/AN4/SS/LVDIN RA6 PORTB RB0/INT0 RB1/INT1 RB2/INT2 RB3/INT3/CCP2 RB4/KBI0 RB5/KBI1/PGM RB6/KBI2/PGC RB7/KBI3/PGD RC0/T1OSO/T13CKI RC1/T1OSI/CCP2 RC2/CCP1 RC3/SCK/SCL RC4/SDI/SDA RC5/SDO RC6/TX1/CK1 RC7/RX1/DT1
21 21
Table Pointer<21> 8 inc/dec logic 8
Data Latch Data RAM Address Latch
System Bus Interface
21
PCLATU PCLATH
12 Address<12> 4
BSR
PCU PCH PCL Program Counter Address Latch Program Memory Data Latch
TABLELATCH
12 FSR0 FSR1 FSR2 inc/dec logic
4
Bank0, F
31 Level Stack
12 PORTC
Decode
16
8
ROMLATCH
AD15:AD0, A19:A16(1)
IR
PORTD 8 PRODH PRODL PORTE RD7/PSP7:RD0/PSP0
Instruction Decode & Control Power-up Timer Timing Generation Oscillator Start-up Timer Power-on Reset Precision Bandgap Reference Watchdog Timer Brown-out Reset
8 x 8 Multiply 3 BITOP 8 WREG 8 8 ALU<8> 8 8 8
OSC2/CLKO OSC1/CLKI
RE0/RD RE1/WR RE2/CS RE3 RE4 RE5 RE6 RE7/CCP2 RF0/AN5 RF1/AN6/C2OUT RF2/AN7/C1OUT RF3/AN8 RF4/AN9 RF5/AN10/CVREF RF6/AN11 RF7/SS
PORTF
PORTG MCLR VDD, VSS
RG0/CCP3 RG1/TX2/CK2 RG2/RX2/DT2 RG3/CCP4 RG4/CCP5 RH3:RH0 RH7/AN15:RH4/AN12
PORTH Synchronous Serial Port USART1 USART2 Data EEPROM PORTJ RJ0/ALE RJ1/OE RJ2/WRL RJ3/WRH RJ4/BA0 RJ5/CE RJ6/LB RJ7/UB 10-bit A/D
BOR LVD
Timer0
Timer1
Timer2
Timer3
Timer4
Comparator Note 1:
CCP1
CCP2
CCP3
CCP4
CCP5
External memory interface pins are physically multiplexed with PORTD (AD7:AD0), PORTE (AD15:AD8) and PORTH (A19:A16).
DS39609A-page 10
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2003 Microchip Technology Inc.
PIC18FXX20
TABLE 1-2:
Pin Name MCLR/VPP MCLR VPP OSC1/CLKI OSC1 39 49 I CMOS/ST
PIC18FXX20 PINOUT I/O DESCRIPTIONS
Pin Type PIC18F6X20 PIC18F8X20 7 9 I P ST Pin Number Buffer Type Description Master Clear (input) or programming voltage (output). Master Clear (RESET) input. This pin is an active low RESET to the device. Programming voltage input. Oscillator crystal or external clock input. Oscillator crystal input or external clock source input. ST buffer when configured in RC mode. Otherwise CMOS. External clock source input. Always associated with pin function OSC1 (see OSC1/CLKI, OSC2/CLKO pins). Oscillator crystal or clock output. Oscillator crystal output. Connects to crystal or resonator in Crystal Oscillator mode. In RC mode, OSC2 pin outputs CLKO, which has 1/4 the frequency of OSC1 and denotes the instruction cycle rate. General purpose I/O pin.
CLKI
I
CMOS
OSC2/CLKO/RA6 OSC2
40
50 O --
CLKO
O
--
RA6
I/O
TTL
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
2003 Microchip Technology Inc.
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DS39609A-page 11
PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 24 30 I/O I 23 29 I/O I 22 28 I/O I I 21 27 I/O I I 28 34 I/O I 27 33 I/O I I TTL Analog Analog Digital I/O. Analog input 4. Low voltage detect input. See the OSC2/CLKO/RA6 pin. ST/OD ST Digital I/O - Open drain when configured as output. Timer0 external clock input. TTL Analog Analog Digital I/O. Analog input 3. A/D reference voltage (High) input. TTL Analog Analog Digital I/O. Analog input 2. A/D reference voltage (Low) input. TTL Analog Digital I/O. Analog input 1. TTL Analog Digital I/O. Analog input 0. Pin Number Buffer Type Description PORTA is a bi-directional I/O port.
RA0/AN0 RA0 AN0 RA1/AN1 RA1 AN1 RA2/AN2/VREFRA2 AN2 VREFRA3/AN3/VREF+ RA3 AN3 VREF+ RA4/T0CKI RA4 T0CKI RA5/AN4/LVDIN RA5 AN4 LVDIN RA6
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
DS39609A-page 12
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2003 Microchip Technology Inc.
PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 Pin Number Buffer Type Description PORTB is a bi-directional I/O port. PORTB can be software programmed for internal weak pull-ups on all inputs.
RB0/INT0 RB0 INT0 RB1/INT1 RB1 INT1 RB2/INT2 RB2 INT2 RB3/INT3/CCP2 RB3 INT3 CCP2(1) RB4/KBI0 RB4 KBI0 RB5/KBI1/PGM RB5 KBI1 PGM RB6/KBI2/PGC RB6 KBI2 PGC RB7/KBI3/PGD RB7 KBI3 PGD
48
58 I/O I TTL ST TTL ST TTL ST TTL ST ST Digital I/O. External interrupt 0. Digital I/O. External interrupt 1. Digital I/O. External interrupt 2. Digital I/O. External interrupt 3. Capture2 input, Compare2 output, PWM2 output. Digital I/O. Interrupt-on-change pin. Digital I/O. Interrupt-on-change pin. Low voltage ICSP programming enable pin. Digital I/O. Interrupt-on-change pin. In-Circuit Debugger and ICSP programming clock. Digital I/O. Interrupt-on-change pin. In-Circuit Debugger and ICSP programming data.
47
57 I/O I
46
56 I/O I
45
55 I/O I/O I/O
44
54 I/O I TTL ST TTL ST ST
43
53 I/O I I/O
42
52 I/O I I/O TTL ST ST
37
47 I/O I/O TTL ST
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
2003 Microchip Technology Inc.
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DS39609A-page 13
PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 30 36 I/O O I 29 35 I/O I I/O 33 43 I/O I/O 34 44 I/O I/O I/O 35 45 I/O I I/O 36 46 I/O O 31 37 I/O O I/O 32 38 I/O I I/O ST ST ST Digital I/O. USART 1 asynchronous receive. USART 1 synchronous data (see TX1/CK1). ST -- ST Digital I/O. USART 1 asynchronous transmit. USART 1 synchronous clock (see RX1/DT1). ST -- Digital I/O. SPI data out. ST ST ST Digital I/O. SPI data in. I2C data I/O. ST ST ST Digital I/O. Synchronous serial clock input/output for SPI mode. Synchronous serial clock input/output for I2C mode. ST ST Digital I/O. Capture1 input/Compare1 output/PWM1 output. ST CMOS ST Digital I/O. Timer1 oscillator input. Capture2 input/Compare2 output/ PWM2 output. ST -- ST Digital I/O. Timer1 oscillator output. Timer1/Timer3 external clock input. Pin Number Buffer Type Description PORTC is a bi-directional I/O port.
RC0/T1OSO/T13CKI RC0 T1OSO T13CKI RC1/T1OSI/CCP2 RC1 T1OSI CCP2(2) RC2/CCP1 RC2 CCP1 RC3/SCK/SCL RC3 SCK SCL RC4/SDI/SDA RC4 SDI SDA RC5/SDO RC5 SDO RC6/TX1/CK1 RC6 TX1 CK1 RC7/RX1/DT1 RC7 RX1 DT1
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
DS39609A-page 14
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PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 Pin Number Buffer Type Description PORTD is a bi-directional I/O port. These pins have TTL input buffers when external memory is enabled.
RD0/PSP0/AD0 RD0 PSP0 AD0(3) RD1/PSP1/AD1 RD1 PSP1 AD1(3) RD2/PSP2/AD2 RD2 PSP2 AD2(3) RD3/PSP3/AD3 RD3 PSP3 AD3(3) RD4/PSP4/AD4 RD4 PSP4 AD4(3) RD5/PSP5/AD5 RD5 PSP5 AD5(3) RD6/PSP6/AD6 RD6 PSP6 AD6(3) RD7/PSP7/AD7 RD7 PSP7 AD7(3)
58
72 I/O I/O I/O ST TTL TTL ST TTL TTL ST TTL TTL ST TTL TTL ST TTL TTL ST TTL TTL ST TTL TTL ST TTL TTL Digital I/O. Parallel Slave Port data. External memory address/data 0. Digital I/O. Parallel Slave Port data. External memory address/data 1. Digital I/O. Parallel Slave Port data. External memory address/data 2. Digital I/O. Parallel Slave Port data. External memory address/data 3. Digital I/O. Parallel Slave Port data. External memory address/data 4. Digital I/O. Parallel Slave Port data. External memory address/data 5. Digital I/O. Parallel Slave Port data. External memory address/data 6. Digital I/O. Parallel Slave Port data. External memory address/data 7.
55
69 I/O I/O I/O
54
68 I/O I/O I/O
53
67 I/O I/O I/O
52
66 I/O I/O I/O
51
65 I/O I/O I/O
50
64 I/O I/O I/O
49
63 I/O I/O I/O
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
2003 Microchip Technology Inc.
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DS39609A-page 15
PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 2 4 I/O I I/O 1 3 I/O I I/O 64 78 I/O I I/O 63 77 I/O I/O 62 76 I/O I/O 61 75 I/O I/O 60 74 I/O I/O 59 73 I/O I/O I/O ST ST TTL Digital I/O. Capture2 input/Compare2 output/ PWM2 output. External memory address/data 15. ST TTL Digital I/O. External memory address/data 14. ST TTL Digital I/O. External memory address/data 13. ST TTL Digital I/O. External memory address/data 12. ST TTL Digital I/O. External memory address/data 11. ST TTL TTL Digital I/O. Chip select control for parallel slave port (see RD and WR). External memory address/data 10. ST TTL TTL Digital I/O. Write control for parallel slave port (see CS and RD pins). External memory address/data 9. ST TTL TTL Digital I/O. Read control for parallel slave port (see WR and CS pins). External memory address/data 8. Pin Number Buffer Type Description PORTE is a bi-directional I/O port.
RE0/RD/AD8 RE0 RD AD8(3) RE1/WR/AD9 RE1 WR AD9(3) RE2/CS/AD10 RE2 CS AD10(3) RE3/AD11 RE3 AD11(3) RE4/AD12 RE4 AD12 RE5/AD13 RE5 AD13(3) RE6/AD14 RE6 AD14(3) RE7/CCP2/AD15 RE7 CCP2(1,4) AD15(3)
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
DS39609A-page 16
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PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 18 24 I/O I 17 23 I/O I O 16 18 I/O I O 15 17 I/O I 14 16 I/O I 13 15 I/O I O 12 14 I/O I 11 13 I/O I ST TTL Digital I/O. SPI slave select input. ST Analog Digital I/O. Analog input 11. ST Analog Analog Digital I/O. Analog input 10. Comparator VREF output. ST Analog Digital I/O. Analog input 9. ST Analog Digital I/O. Analog input 8. ST Analog ST Digital I/O. Analog input 7. Comparator 1 output. ST Analog ST Digital I/O. Analog input 6. Comparator 2 output. ST Analog Digital I/O. Analog input 5. Pin Number Buffer Type Description PORTF is a bi-directional I/O port.
RF0/AN5 RF0 AN5 RF1/AN6/C2OUT RF1 AN6 C2OUT RF2/AN7/C1OUT RF2 AN7 C1OUT RF3/AN8 RF1 AN8 RF4/AN9 RF1 AN9 RF5/AN10/CVREF RF1 AN10 CVREF RF6/AN11 RF6 AN11 RF7/SS RF7 SS
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
2003 Microchip Technology Inc.
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DS39609A-page 17
PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 3 5 I/O I/O 4 6 I/O O I/O 5 7 I/O I I/O 6 8 I/O I/O 8 10 I/O I/O ST ST Digital I/O. Capture5 input/Compare5 output/ PWM5 output. ST ST Digital I/O. Capture4 input/Compare4 output/ PWM4 output. ST ST ST Digital I/O. USART 2 asynchronous receive. USART 2 synchronous data (see TX2/CK2). ST -- ST Digital I/O. USART 2 asynchronous transmit. USART 2 synchronous clock (see RX2/DT2). ST ST Digital I/O. Capture3 input/Compare3 output/ PWM3 output. Pin Number Buffer Type Description PORTG is a bi-directional I/O port.
RG0/CCP3 RG0 CCP3 RG1/TX2/CK2 RG1 TX2 CK2 RG2/RX2/DT2 RG2 RX2 DT2 RG3/CCP4 RG3 CCP4 RG4/CCP5 RG4 CCP5
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
DS39609A-page 18
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PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 -- 79 I/O O -- 80 I/O O -- 1 I/O O -- 2 I/O O -- 22 I/O I -- 21 I/O I -- 20 I/O I -- 19 I/O I ST Analog Digital I/O. Analog input 15. ST Analog Digital I/O. Analog input 14. ST Analog Digital I/O. Analog input 13. ST Analog Digital I/O. Analog input 12. ST TTL Digital I/O. External memory address 19. ST TTL Digital I/O. External memory address 18. ST TTL Digital I/O. External memory address 17. ST TTL Digital I/O. External memory address 16. Pin Number Buffer Type Description PORTH is a bi-directional I/O port(5).
RH0/A16 RH0 A16 RH1/A17 RH1 A17 RH2/A18 RH2 A18 RH3/A19 RH3 A19 RH4/AN12 RH4 AN12 RH5/AN13 RH5 AN13 RH6/AN14 RH6 AN14 RH7/AN15 RH7 AN15
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
2003 Microchip Technology Inc.
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DS39609A-page 19
PIC18FXX20
TABLE 1-2:
Pin Name
PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Type PIC18F6X20 PIC18F8X20 -- 62 I/O O -- 61 I/O O -- 60 I/O O -- 59 I/O O -- 39 I/O O -- 40 I/O O -- 41 I/O O -- 42 I/O O 9, 25, 41, 56 10, 26, 38, 57 20 19 11, 31, 51, 70 12, 32, 48, 71 26 25 P P P P ST TTL -- -- -- -- Digital I/O. External memory High Byte select. Ground reference for logic and I/O pins. Positive supply for logic and I/O pins. Ground reference for analog modules. Positive supply for analog modules. ST TTL Digital I/O. External memory Low Byte select. ST TTL Digital I/O. External memory Chip Enable control. ST TTL Digital I/O. External memory Byte Address 0 control. ST TTL Digital I/O. External memory Write High control. ST TTL Digital I/O. External memory Write Low control. ST TTL Digital I/O. External memory Output Enable. ST TTL Digital I/O. External memory Address Latch Enable. Pin Number Buffer Type Description PORTJ is a bi-directional I/O port(5).
RJ0/ALE RJ0 ALE RJ1/OE RJ1 OE RJ2/WRL RJ2 WRL RJ3/WRH RJ3 WRH RJ4/BA0 RJ4 BA0 RJ5/CE RJ5 CE RJ6/LB RJ6 LB RJ7/UB RJ7 UB VSS VDD AVSS(6) AVDD(6)
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open Drain (no P diode to VDD) Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all Operating modes except Microcontroller). 2: Default assignment when CCP2MX is set. 3: External memory interface functions are only available on PIC18F8X20 devices. 4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is multiplexed with either RB3 or RC1. 5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices. 6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for proper operation of the part in User or ICSP modes. See parameter D001A for details.
DS39609A-page 20
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PIC18FXX20
2.0
2.1
OSCILLATOR CONFIGURATIONS
Oscillator Types
TABLE 2-1:
CAPACITOR SELECTION FOR CERAMIC RESONATORS
Ranges Tested:
The PIC18FXX20 devices can be operated in eight different Oscillator modes. The user can program three configuration bits (FOSC2, FOSC1, and FOSC0) to select one of these eight modes: 1. 2. 3. 4. 5. 6. 7. 8. LP XT HS HS+PLL RC RCIO EC ECIO Low Power Crystal Crystal/Resonator High Speed Crystal/Resonator High Speed Crystal/Resonator with PLL enabled External Resistor/Capacitor External Resistor/Capacitor with I/O pin enabled External Clock External Clock with I/O pin enabled
Mode XT
Freq
C1
C2
455 kHz 68 - 100 pF 68 - 100 pF 2.0 MHz 15 - 68 pF 15 - 68 pF 4.0 MHz 15 - 68 pF 15 - 68 pF HS 8.0 MHz 10 - 68 pF 10 - 68 pF 16.0 MHz 10 - 22 pF 10 - 22 pF These values are for design guidance only. See notes following this table. Resonators Used: 455 kHz Panasonic EFO-A455K04B 0.3% 2.0 MHz Murata Erie CSA2.00MG 0.5% 4.0 MHz Murata Erie CSA4.00MG 0.5% 8.0 MHz Murata Erie CSA8.00MT 0.5% 16.0 MHz Murata Erie CSA16.00MX 0.5% All resonators used did not have built-in capacitors.
2.2
Crystal Oscillator/Ceramic Resonators
In XT, LP, HS or HS+PLL Oscillator modes, a crystal or ceramic resonator is connected to the OSC1 and OSC2 pins to establish oscillation. Figure 2-1 shows the pin connections. The PIC18FXX20 oscillator design requires the use of a parallel cut crystal. Note: Use of a series cut crystal may give a frequency out of the crystal manufacturer's specifications.
Note 1: Higher capacitance increases the stability of the oscillator, but also increases the start-up time. 2: When operating below 3V VDD, or when using certain ceramic resonators at any voltage, it may be necessary to use high gain HS mode, try a lower frequency resonator, or switch to a crystal oscillator. 3: Since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropriate values of external components, or verify oscillator performance.
FIGURE 2-1:
CRYSTAL/CERAMIC RESONATOR OPERATION (HS, XT OR LP CONFIGURATION)
OSC1 To Internal Logic SLEEP
C1(1)
XTAL
RS(2) C2(1) OSC2
RF(3)
PIC18FXX20
Note 1: See Table 2-1 and Table 2-2 for recommended values of C1 and C2. 2: A series resistor (RS) may be required for AT strip cut crystals. 3: RF varies with the Oscillator mode chosen.
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DS39609A-page 21
PIC18FXX20
TABLE 2-2: CAPACITOR SELECTION FOR CRYSTAL OSCILLATOR
Ranges Tested: Mode LP XT Freq 32.0 kHz 200 kHz 200 kHz 1.0 MHz 4.0 MHz HS 4.0 MHz 8.0 MHz 20.0 MHz 25.0 MHz C1 33 pF 15 pF 47-68 pF 15 pF 15 pF 15 pF 15-33 pF 15-33 pF TBD C2 33 pF 15 pF 47-68 pF 15 pF 15 pF 15 pF 15-33 pF 15-33 pF TBD
Clock from Ext. System Open OSC1
FIGURE 2-2:
EXTERNAL CLOCK INPUT OPERATION (HS, XT OR LP OSC CONFIGURATION)
PIC18FXX20
OSC2
2.3
RC Oscillator
These values are for design guidance only. See notes following this table. Crystals Used 32.0 kHz 200 kHz 1.0 MHz 4.0 MHz 8.0 MHz 20.0 MHz Epson C-001R32.768K-A STD XTL 200.000KHz ECS ECS-10-13-1 ECS ECS-40-20-1 Epson CA-301 8.000M-C 20 PPM 20 PPM 50 PPM 50 PPM 30 PPM
For timing insensitive applications, the "RC" and "RCIO" device options offer additional cost savings. The RC oscillator frequency is a function of the supply voltage, the resistor (REXT) and capacitor (CEXT) values and the operating temperature. In addition to this, the oscillator frequency will vary from unit to unit, due to normal process parameter variation. Furthermore, the difference in lead frame capacitance between package types will also affect the oscillation frequency, especially for low CEXT values. The user also needs to take into account variation due to tolerance of external R and C components used. Figure 2-3 shows how the R/C combination is connected. In the RC Oscillator mode, the oscillator frequency divided by 4 is available on the OSC2 pin. This signal may be used for test purposes or to synchronize other logic.
Epson CA-301 20.000M-C 30 PPM
FIGURE 2-3:
Note 1: Higher capacitance increases the stability of the oscillator, but also increases the start-up time. 2: Rs (see Figure 2-1) may be required in HS mode, as well as XT mode, to avoid overdriving crystals with low drive level specification. 3: Since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropriate values of external components, or verify oscillator performance. An external clock source may also be connected to the OSC1 pin in the HS, XT and LP modes, as shown in Figure 2-2.
VDD REXT
RC OSCILLATOR MODE
OSC1 CEXT VSS FOSC/4 Recommended values: OSC2/CLKO
Internal Clock
PIC18FXX20
3 k REXT 100 k CEXT > 20 pF
The RCIO Oscillator mode functions like the RC mode, except that the OSC2 pin becomes an additional general purpose I/O pin. The I/O pin becomes bit 6 of PORTA (RA6).
DS39609A-page 22
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PIC18FXX20
2.4 External Clock Input
FIGURE 2-5:
The EC and ECIO Oscillator modes require an external clock source to be connected to the OSC1 pin. The feedback device between OSC1 and OSC2 is turned off in these modes to save current. There is a maximum 1.5 s start-up required after a Power-on Reset, or wake-up from SLEEP mode. In the EC Oscillator mode, the oscillator frequency divided by 4 is available on the OSC2 pin. This signal may be used for test purposes or to synchronize other logic. Figure 2-4 shows the pin connections for the EC Oscillator mode.
EXTERNAL CLOCK INPUT OPERATION (ECIO CONFIGURATION)
OSC1
Clock from Ext. System RA6
PIC18FXX20
I/O (OSC2)
2.5
HS/PLL
FIGURE 2-4:
EXTERNAL CLOCK INPUT OPERATION (EC CONFIGURATION)
OSC1
A Phase Locked Loop circuit (PLL) is provided as a programmable option for users that want to multiply the frequency of the incoming crystal oscillator signal by 4. For an input clock frequency of 10 MHz, the internal clock frequency will be multiplied to 40 MHz. This is useful for customers who are concerned with EMI due to high frequency crystals. The PLL is one of the modes of the FOSC<2:0> configuration bits. The Oscillator mode is specified during device programming. The PLL can only be enabled when the oscillator configuration bits are programmed for HS mode. If they are programmed for any other mode, the PLL is not enabled and the system clock will come directly from OSC1. Also, PLL operation cannot be changed "on-the-fly". To enable or disable it, the controller must either cycle through a Power-on Reset, or switch the clock source from the main oscillator to the Timer1 oscillator and back again. (See Section 2.6 for details on Oscillator Switching.) A PLL lock timer is used to ensure that the PLL has locked before device execution starts. The PLL lock timer has a time-out that is called TPLL.
Clock from Ext. System FOSC/4
PIC18FXX20
OSC2
The ECIO Oscillator mode functions like the EC mode, except that the OSC2 pin becomes an additional general purpose I/O pin. The I/O pin becomes bit 6 of PORTA (RA6). Figure 2-5 shows the pin connections for the ECIO Oscillator mode.
FIGURE 2-6:
PLL BLOCK DIAGRAM
HS Osc PLL Enable Phase Comparator Crystal Osc FIN FOUT Loop Filter VCO SYSCLK
(from Configuration bit Register)
OSC2
OSC1
Divide by 4
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MUX
PIC18FXX20
2.6 Oscillator Switching Feature
The PIC18FXX20 devices include a feature that allows the system clock source to be switched from the main oscillator to an alternate low frequency clock source. For the PIC18FXX20 devices, this alternate clock source is the Timer1 oscillator. If a low frequency crystal (32 kHz, for example) has been attached to the Timer1 oscillator pins and the Timer1 oscillator has been enabled, the device can switch to a Low Power Execution mode. Figure 2-7 shows a block diagram of the system clock sources. The clock switching feature is enabled by programming the Oscillator Switching Enable (OSCSEN) bit in Configuration Register1H to a `0'. Clock switching is disabled in an erased device. See Section 12.0 for further details of the Timer1 oscillator. See Section 23.0 for Configuration Register details.
FIGURE 2-7:
DEVICE CLOCK SOURCES
PIC18FXX20
Main Oscillator OSC2 SLEEP OSC1 Timer1 Oscillator T1OSO T1OSCEN Enable Oscillator Clock Source Option for Other Modules 4 x PLL TOSC TT1P Clock Source TOSC/4 TSCLK
MUX
T1OSI
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PIC18FXX20
2.6.1 SYSTEM CLOCK SWITCH BIT
Note: The system clock source switching is performed under software control. The system clock switch bit, SCS (OSCCON<0>) controls the clock switching. When the SCS bit is `0', the system clock source comes from the main oscillator that is selected by the FOSC configuration bits in Configuration Register1H. When the SCS bit is set, the system clock source will come from the Timer1 oscillator. The SCS bit is cleared on all forms of RESET. The Timer1 oscillator must be enabled and operating to switch the system clock source. The Timer1 oscillator is enabled by setting the T1OSCEN bit in the Timer1 Control register (T1CON). If the Timer1 oscillator is not enabled, then any write to the SCS bit will be ignored (SCS bit forced cleared) and the main oscillator will continue to be the system clock source.
REGISTER 2-1:
OSCCON REGISTER
U-0 -- bit 7 U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- R/W-1 SCS bit 0
bit 7-1 bit 0
Unimplemented: Read as '0' SCS: System Clock Switch bit When OSCSEN configuration bit = 0 and T1OSCEN bit is set: 1 = Switch to Timer1 oscillator/clock pin 0 = Use primary oscillator/clock input pin When OSCSEN and T1OSCEN are in other states: Bit is forced clear Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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PIC18FXX20
2.6.2 OSCILLATOR TRANSITIONS
PIC18FXX20 devices contain circuitry to prevent "glitches" when switching between oscillator sources. Essentially, the circuitry waits for eight rising edges of the clock source that the processor is switching to. This ensures that the new clock source is stable and that its pulse width will not be less than the shortest pulse width of the two clock sources. A timing diagram indicating the transition from the main oscillator to the Timer1 oscillator is shown in Figure 2-8. The Timer1 oscillator is assumed to be running all the time. After the SCS bit is set, the processor is frozen at the next occurring Q1 cycle. After eight synchronization cycles are counted from the Timer1 oscillator, operation resumes. No additional delays are required after the synchronization cycles.
FIGURE 2-8:
Q1 Q2
TIMING DIAGRAM FOR TRANSITION FROM OSC1 TO TIMER1 OSCILLATOR
Q3 Q4 Q1 1 TT1P 2 3 4 TSCS 5 6 7 8 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
T1OSI OSC1 Internal System Clock SCS (OSCCON<0>) Program Counter
TOSC TDLY
PC
PC + 2
PC + 4
Note 1: Delay on internal system clock is eight oscillator cycles for synchronization.
The sequence of events that takes place when switching from the Timer1 oscillator to the main oscillator will depend on the mode of the main oscillator. In addition to eight clock cycles of the main oscillator, additional delays may take place.
If the main oscillator is configured for an external crystal (HS, XT, LP), then the transition will take place after an oscillator start-up time (TOST) has occurred. A timing diagram, indicating the transition from the Timer1 oscillator to the main oscillator for HS, XT and LP modes, is shown in Figure 2-9.
FIGURE 2-9:
Q3
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS, XT, LP)
Q4 Q1 TT1P Q1 Q2 Q3 Q4 Q1 Q2 Q3
T1OSI OSC1
TOST 1 2 3 4 5 TSCS 6 7 8
OSC2 Internal System Clock SCS (OSCCON<0>) Program Counter
TOSC
PC
PC + 2
PC + 6
Note 1: TOST = 1024 TOSC (drawing not to scale).
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PIC18FXX20
If the main oscillator is configured for HS-PLL mode, an oscillator start-up time (TOST), plus an additional PLL time-out (TPLL), will occur. The PLL time-out is typically 2 ms and allows the PLL to lock to the main oscillator frequency. A timing diagram, indicating the transition from the Timer1 oscillator to the main oscillator for HS-PLL mode, is shown in Figure 2-10.
FIGURE 2-10:
Q4
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS WITH PLL)
Q1 TT1P Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
T1OSI OSC1
TOST TPLL
OSC2 PLL Clock Input Internal System Clock SCS (OSCCON<0>) Program Counter
PC PC + 2 PC + 4 TOSC
1 2 3
TSCS
4 5 6 7 8
Note 1: TOST = 1024 TOSC (drawing not to scale).
If the main oscillator is configured in the RC, RCIO, EC or ECIO modes, there is no oscillator start-up time-out. Operation will resume after eight cycles of the main oscillator have been counted. A timing diagram, indi-
cating the transition from the Timer1 oscillator to the main oscillator for RC, RCIO, EC and ECIO modes, is shown in Figure 2-11.
FIGURE 2-11:
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)
Q3 Q4 Q1 TT1P TOSC 1 2 3 4 5 6 7 8 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
T1OSI OSC1 OSC2 Internal System Clock SCS (OSCCON<0>) Program Counter
TSCS PC PC + 2 PC + 4
Note 1: RC Oscillator mode assumed.
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PIC18FXX20
2.7 Effects of SLEEP Mode on the On-Chip Oscillator
switching currents have been removed, SLEEP mode achieves the lowest current consumption of the device (only leakage currents). Enabling any on-chip feature that will operate during SLEEP, will increase the current consumed during SLEEP. The user can wake from SLEEP through external RESET, Watchdog Timer Reset, or through an interrupt.
When the device executes a SLEEP instruction, the on-chip clocks and oscillator are turned off and the device is held at the beginning of an instruction cycle (Q1 state). With the oscillator off, the OSC1 and OSC2 signals will stop oscillating. Since all the transistor
TABLE 2-3:
OSC Mode RC RCIO ECIO EC LP, XT, and HS Note:
OSC1 AND OSC2 PIN STATES IN SLEEP MODE
OSC1 Pin Floating, external resistor should pull high Floating, external resistor should pull high Floating Floating Feedback inverter disabled, at quiescent voltage level OSC2 Pin At logic low Configured as PORTA, bit 6 Configured as PORTA, bit 6 At logic low Feedback inverter disabled, at quiescent voltage level
See Table 3-1 in the "Reset" section, for time-outs due to SLEEP and MCLR Reset.
2.8
Power-up Delays
Power up delays are controlled by two timers, so that no external RESET circuitry is required for most applications. The delays ensure that the device is kept in RESET until the device power supply and clock are stable. For additional information on RESET operation, see the "Reset" section. The first timer is the Power-up Timer (PWRT), which optionally provides a fixed delay of 72 ms (nominal) on power-up only (POR and BOR). The second timer is the Oscillator Start-up Timer (OST), intended to keep the chip in RESET until the crystal oscillator is stable.
With the PLL enabled (HS/PLL Oscillator mode), the time-out sequence following a Power-on Reset is different from other Oscillator modes. The time-out sequence is as follows: First, the PWRT time-out is invoked after a POR time delay has expired. Then, the Oscillator Start-up Timer (OST) is invoked. However, this is still not a sufficient amount of time to allow the PLL to lock at high frequencies. The PWRT timer is used to provide an additional fixed 2 ms (nominal) time-out to allow the PLL ample time to lock to the incoming clock frequency.
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PIC18FXX20
3.0 RESET
differentiate between The PIC18FXX20 devices various kinds of RESET: a) b) c) d) e) f) g) h) state" on Power-on Reset, MCLR, WDT Reset, Brown-out Reset, MCLR Reset during SLEEP and by the RESET instruction. Most registers are not affected by a WDT wake-up, since this is viewed as the resumption of normal operation. Status bits from the RCON register, RI, TO, PD, POR and BOR, are set or cleared differently in different RESET situations, as indicated in Table 3-2. These bits are used in software to determine the nature of the RESET. See Table 3-3 for a full description of the RESET states of all registers. A simplified block diagram of the On-Chip Reset Circuit is shown in Figure 3-1. The Enhanced MCU devices have a MCLR noise filter in the MCLR Reset path. The filter will detect and ignore small pulses. The MCLR pin is not driven low by any internal RESETS, including the WDT.
Power-on Reset (POR) MCLR Reset during normal operation MCLR Reset during SLEEP Watchdog Timer (WDT) Reset (during normal operation) Programmable Brown-out Reset (PBOR) RESET Instruction Stack Full Reset Stack Underflow Reset
Most registers are unaffected by a RESET. Their status is unknown on POR and unchanged by all other RESETS. The other registers are forced to a "RESET
FIGURE 3-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
RESET Instruction
Stack Pointer
Stack Full/Underflow Reset
External Reset MCLR WDT Module WDT Time-out Reset SLEEP
VDD Rise Power-on Reset Detect VDD Brown-out Reset OST/PWRT OST 10-bit Ripple Counter OSC1 PWRT 10-bit Ripple Counter R Q Chip_Reset
BOREN
S
On-chip RC OSC(1)
Enable PWRT
Enable OST(2) Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin. 2: See Table 3-1 for time-out situations.
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PIC18FXX20
3.1 Power-on Reset (POR) 3.3 Oscillator Start-up Timer (OST)
A Power-on Reset pulse is generated on-chip when VDD rise is detected. To take advantage of the POR circuitry, tie the MCLR pin through a 1 k to 10 k resistor to VDD. This will eliminate external RC components usually needed to create a Power-on Reset delay. A minimum rise rate for VDD is specified (parameter D004). For a slow rise time, see Figure 3-2. When the device starts normal operation (i.e., exits the RESET condition), device operating parameters (voltage, frequency, temperature, etc.) must be met to ensure operation. If these conditions are not met, the device must be held in RESET until the operating conditions are met. The Oscillator Start-up Timer (OST) provides 1024 oscillator cycle (from OSC1 input) delay after the PWRT delay is over (parameter #32). This ensures that the crystal oscillator or resonator has started and stabilized. The OST time-out is invoked only for XT, LP and HS modes and only on Power-on Reset, or wake-up from SLEEP.
3.4
PLL Lock Time-out
FIGURE 3-2:
EXTERNAL POWER-ON RESET CIRCUIT (FOR SLOW VDD POWER-UP)
VDD
With the PLL enabled, the time-out sequence following a Power-on Reset is different from other oscillator modes. A portion of the Power-up Timer is used to provide a fixed time-out that is sufficient for the PLL to lock to the main oscillator frequency. This PLL lock time-out (TPLL) is typically 2 ms and follows the oscillator start-up time-out (OST).
3.5
Brown-out Reset (BOR)
D
R R1 C MCLR
PIC18FXX20
Note 1: External Power-on Reset circuit is required only if the VDD power-up slope is too slow. The diode D helps discharge the capacitor quickly when VDD powers down. 2: R < 40 k is recommended to make sure that the voltage drop across R does not violate the device's electrical specification. 3: R1 = 1 k to 10 k will limit any current flowing into MCLR from external capacitor C, in the event of MCLR/VPP pin breakdown due to Electrostatic Discharge (ESD), or Electrical Overstress (EOS).
A configuration bit, BOREN, can disable (if clear/programmed), or enable (if set) the Brown-out Reset circuitry. If VDD falls below parameter D005 for greater than parameter #35, the brown-out situation will reset the chip. A RESET may not occur if VDD falls below parameter D005 for less than parameter #35. The chip will remain in Brown-out Reset until VDD rises above BVDD. If the Power-up Timer is enabled, it will be invoked after VDD rises above BVDD; it then will keep the chip in RESET for an additional time delay (parameter #33). If VDD drops below BVDD while the Power-up Timer is running, the chip will go back into a Brown-out Reset and the Power-up Timer will be initialized. Once VDD rises above BVDD, the Power-up Timer will execute the additional time delay.
3.6
Time-out Sequence
3.2
Power-up Timer (PWRT)
The Power-up Timer provides a fixed nominal time-out (parameter #33) only on power-up from the POR. The Power-up Timer operates on an internal RC oscillator. The chip is kept in RESET as long as the PWRT is active. The PWRT's time delay allows VDD to rise to an acceptable level. A configuration bit is provided to enable/disable the PWRT. The power-up time delay will vary from chip-to-chip due to VDD, temperature and process variation. See DC parameter #33 for details.
On power-up, the time-out sequence is as follows: First, PWRT time-out is invoked after the POR time delay has expired. Then, OST is activated. The total time-out will vary based on oscillator configuration and the status of the PWRT. For example, in RC mode with the PWRT disabled, there will be no time-out at all. Figure 3-3, Figure 3-4, Figure 3-5, Figure 3-6 and Figure 3-7 depict time-out sequences on power-up. Since the time-outs occur from the POR pulse, the time-outs will expire if MCLR is kept low long enough. Bringing MCLR high will begin execution immediately (Figure 3-5). This is useful for testing purposes, or to synchronize more than one PIC18FXX20 device operating in parallel. Table 3-2 shows the RESET conditions for some Special Function Registers, while Table 3-3 shows the RESET conditions for all of the registers.
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PIC18FXX20
TABLE 3-1: TIME-OUT IN VARIOUS SITUATIONS
Power-up(2) PWRTE = 0 72 ms + 1024 TOSC + 2ms 72 ms + 1024 TOSC 72 ms 72 ms PWRTE = 1 1024 TOSC + 2 ms 1024 TOSC 1.5 s -- Brown-out 72 ms(2) + 1024 TOSC + 2 ms 72 ms(2) + 1024 TOSC 72 ms(2) 72 ms(2) Wake-up from SLEEP or Oscillator Switch 1024 TOSC + 2 ms 1024 TOSC 1.5 s(3) -- Oscillator Configuration HS with PLL enabled(1) HS, XT, LP EC External RC
Note 1: 2 ms is the nominal time required for the 4xPLL to lock. 2: 72 ms is the nominal power-up timer delay, if implemented. 3: 1.5 s is the recovery time from SLEEP. There is no recovery time from oscillator switch.
REGISTER 3-1:
RCON REGISTER BITS AND POSITIONS
R/W-0 IPEN bit 7 Note 1: Refer to Section 4.14 (page 60) for bit definitions. U-0 -- U-0 -- R/W-1 RI R/W-1 TO R/W-1 PD R/W-1 POR R/W-1 BOR bit 0
TABLE 3-2:
STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR RCON REGISTER
Program Counter 0000h 0000h 0000h 0000h 0000h 0000h 0000h PC + 2 0000h PC + 2(1) RCON Register 0--1 1100 0--u uuuu 0--0 uuuu 0--u uu11 0--u uu11 0--u 10uu 0--u 01uu u--u 00uu 0--1 11u0 u--u 00uu RI 1 u 0 u u u 1 u 1 u TO 1 u u u u 1 0 0 1 1 PD 1 u u u u 0 1 0 1 0 POR 0 u u u u u u u 1 u BOR 0 u u u u u u u 0 u STKFUL u u u u 1 u u u u u STKUNF u u u 1 u u u u u u
Condition Power-on Reset MCLR Reset during normal operation Software Reset during normal operation Stack Full Reset during normal operation Stack Underflow Reset during normal operation MCLR Reset during SLEEP WDT Reset WDT Wake-up Brown-out Reset Interrupt wake-up from SLEEP
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0' Note 1: When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the interrupt vector (0x000008h or 0x000018h).
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PIC18FXX20
TABLE 3-3:
Register
INITIALIZATION CONDITIONS FOR ALL REGISTERS
Applicable Devices Power-on Reset, Brown-out Reset MCLR Resets WDT Reset RESET Instruction Stack Resets Wake-up via WDT or Interrupt
---0 0000 TOSU PIC18F6X20 PIC18F8X20 ---0 0000 ---0 uuuu(3) TOSH PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu(3) TOSL PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu(3) STKPTR PIC18F6X20 PIC18F8X20 00-0 0000 uu-0 0000 uu-u uuuu(3) PCLATU PIC18F6X20 PIC18F8X20 ---0 0000 ---0 0000 ---u uuuu PCLATH PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu PCL PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 PC + 2(2) TBLPTRU PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu TBLPTRH PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TBLPTRL PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TABLAT PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu PRODH PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu PRODL PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu INTCON PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu(1) INTCON2 PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu(1) INTCON3 PIC18F6X20 PIC18F8X20 1100 0000 1100 0000 uuuu uuuu(1) INDF0 PIC18F6X20 PIC18F8X20 N/A N/A N/A POSTINC0 PIC18F6X20 PIC18F8X20 N/A N/A N/A POSTDEC0 PIC18F6X20 PIC18F8X20 N/A N/A N/A PREINC0 PIC18F6X20 PIC18F8X20 N/A N/A N/A PLUSW0 PIC18F6X20 PIC18F8X20 N/A N/A N/A FSR0H PIC18F6X20 PIC18F8X20 ---- xxxx ---- uuuu ---- uuuu FSR0L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu WREG PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu INDF1 PIC18F6X20 PIC18F8X20 N/A N/A N/A POSTINC1 PIC18F6X20 PIC18F8X20 N/A N/A N/A POSTDEC1 PIC18F6X20 PIC18F8X20 N/A N/A N/A PREINC1 PIC18F6X20 PIC18F8X20 N/A N/A N/A PLUSW1 PIC18F6X20 PIC18F8X20 N/A N/A N/A Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition. Shaded cells indicate conditions do not apply for the designated device. Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up). 2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt vector (0008h or 0018h). 3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are updated with the current value of the PC. The STKPTR is modified to point to the next location in the hardware stack. 4: See Table 3-2 for RESET value for specific condition. 5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other Oscillator modes, they are disabled and read `0'. 6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read `0'.
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PIC18FXX20
TABLE 3-3:
Register FSR1H
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices Power-on Reset, Brown-out Reset MCLR Resets WDT Reset RESET Instruction Stack Resets Wake-up via WDT or Interrupt
---- xxxx ---- uuuu ---- uuuu PIC18F6X20 PIC18F8X20 FSR1L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu BSR PIC18F6X20 PIC18F8X20 ---- 0000 ---- 0000 ---- uuuu INDF2 PIC18F6X20 PIC18F8X20 N/A N/A N/A POSTINC2 PIC18F6X20 PIC18F8X20 N/A N/A N/A POSTDEC2 PIC18F6X20 PIC18F8X20 N/A N/A N/A PREINC2 PIC18F6X20 PIC18F8X20 N/A N/A N/A PLUSW2 PIC18F6X20 PIC18F8X20 N/A N/A N/A FSR2H PIC18F6X20 PIC18F8X20 ---- xxxx ---- uuuu ---- uuuu FSR2L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu STATUS PIC18F6X20 PIC18F8X20 ---x xxxx ---u uuuu ---u uuuu TMR0H PIC18F6X20 PIC18F8X20 0000 0000 uuuu uuuu uuuu uuuu TMR0L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu T0CON PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu OSCCON PIC18F6X20 PIC18F8X20 ---- ---0 ---- ---0 ---- ---u LVDCON PIC18F6X20 PIC18F8X20 --00 0101 --00 0101 --uu uuuu WDTCON PIC18F6X20 PIC18F8X20 ---- ---0 ---- ---0 ---- ---u RCON(4) PIC18F6X20 PIC18F8X20 0--q 11qq 0--q qquu u--u qquu TMR1H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu TMR1L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu T1CON PIC18F6X20 PIC18F8X20 0-00 0000 u-uu uuuu u-uu uuuu TMR2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu PR2 PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 1111 1111 T2CON PIC18F6X20 PIC18F8X20 -000 0000 -000 0000 -uuu uuuu SSPBUF PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu SSPADD PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu SSPSTAT PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu SSPCON1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu SSPCON2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition. Shaded cells indicate conditions do not apply for the designated device. Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up). 2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt vector (0008h or 0018h). 3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are updated with the current value of the PC. The STKPTR is modified to point to the next location in the hardware stack. 4: See Table 3-2 for RESET value for specific condition. 5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other Oscillator modes, they are disabled and read `0'. 6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read `0'.
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PIC18FXX20
TABLE 3-3:
Register ADRESH
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices Power-on Reset, Brown-out Reset MCLR Resets WDT Reset RESET Instruction Stack Resets Wake-up via WDT or Interrupt
xxxx xxxx uuuu uuuu uuuu uuuu PIC18F6X20 PIC18F8X20 ADRESL PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu ADCON0 PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu ADCON1 PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu ADCON2 PIC18F6X20 PIC18F8X20 0--- -000 0--- -000 u--- -uuu CCPR1H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCPR1L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCP1CON PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu CCPR2H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCPR2L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCP2CON PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu CCPR3H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCPR3L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCP3CON PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu CVRCON PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu CMCON PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TMR3H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu TMR3L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu T3CON PIC18F6X20 PIC18F8X20 0000 0000 uuuu uuuu uuuu uuuu PSPCON PIC18F6X20 PIC18F8X20 0000 ---0000 ---uuuu ---SPBRG1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu RCREG1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TXREG1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TXSTA1 PIC18F6X20 PIC18F8X20 0000 -010 0000 -010 uuuu -uuu RCSTA1 PIC18F6X20 PIC18F8X20 0000 000x 0000 000x uuuu uuuu EEADRH PIC18F6X20 PIC18F8X20 ---- --00 ---- --00 ---- --uu EEADR PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu EEDATA PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu EECON2 PIC18F6X20 PIC18F8X20 xx-0 x000 uu-0 u000 uu-0 u000 EECON1 PIC18F6X20 PIC18F8X20 ---- ------- ------- ---Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition. Shaded cells indicate conditions do not apply for the designated device. Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up). 2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt vector (0008h or 0018h). 3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are updated with the current value of the PC. The STKPTR is modified to point to the next location in the hardware stack. 4: See Table 3-2 for RESET value for specific condition. 5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other Oscillator modes, they are disabled and read `0'. 6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read `0'.
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TABLE 3-3:
Register IPR3
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices Power-on Reset, Brown-out Reset MCLR Resets WDT Reset RESET Instruction Stack Resets Wake-up via WDT or Interrupt
--11 1111 --11 1111 --uu uuuu PIC18F6X20 PIC18F8X20 PIR3 PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu PIE3 PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuu IPR2 PIC18F6X20 PIC18F8X20 -1-1 1111 -1-1 1111 -u-u uuuu PIR2 PIC18F6X20 PIC18F8X20 -0-0 0000 -0-0 0000 -u-u uuuu(1) PIE2 PIC18F6X20 PIC18F8X20 -0-0 0000 -0-0 0000 -u-u uuuu IPR1 PIC18F6X20 PIC18F8X20 0111 1111 0111 1111 uuuu uuuu PIR1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu(1) PIE1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu MEMCON PIC18F6X20 PIC18F8X20 0-00 --00 0-00 --00 u-uu --uu TRISJ PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu TRISH PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu TRISG PIC18F6X20 PIC18F8X20 ---1 1111 ---1 1111 ---u uuuu TRISF PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu TRISE PIC18F6X20 PIC18F8X20 0000 -111 0000 -111 uuuu -uuu TRISD PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu TRISC PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu TRISB PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu TRISA(5,6) PIC18F6X20 PIC18F8X20 -111 1111(5) -111 1111(5) -uuu uuuu(5) LATJ PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu LATH PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu LATG PIC18F6X20 PIC18F8X20 ---x xxxx ---u uuuu ---u uuuu LATF PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu LATE PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu LATD PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu LATC PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu LATB PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu (5,6) (5) (5) LATA PIC18F6X20 PIC18F8X20 -xxx xxxx -uuu uuuu -uuu uuuu(5) Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition. Shaded cells indicate conditions do not apply for the designated device. Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up). 2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt vector (0008h or 0018h). 3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are updated with the current value of the PC. The STKPTR is modified to point to the next location in the hardware stack. 4: See Table 3-2 for RESET value for specific condition. 5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other Oscillator modes, they are disabled and read `0'. 6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read `0'.
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PIC18FXX20
TABLE 3-3:
Register PORTJ
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices Power-on Reset, Brown-out Reset MCLR Resets WDT Reset RESET Instruction Stack Resets Wake-up via WDT or Interrupt
xxxx xxxx uuuu uuuu uuuu uuuu PIC18F6X20 PIC18F8X20 PORTH PIC18F6X20 PIC18F8X20 0000 xxxx 0000 uuuu uuuu uuuu PORTG PIC18F6X20 PIC18F8X20 ---x xxxx uuuu uuuu ---u uuuu PORTF PIC18F6X20 PIC18F8X20 x000 0000 u000 0000 u000 0000 PORTE PIC18F6X20 PIC18F8X20 ---- -000 ---- -000 ---- -uuu PORTD PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu PORTC PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu PORTB PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu PORTA(5,6) PIC18F6X20 PIC18F8X20 -x0x 0000(5) -u0u 0000(5) -uuu uuuu(5) TMR4 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu PR4 PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu T4CON PIC18F6X20 PIC18F8X20 -000 0000 -000 0000 -uuu uuuu CCPR4H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCPR4L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCP4CON PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu CCPR5H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCPR5L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu CCP5CON PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu SPBRG2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu RCREG2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TXREG2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu TXSTA2 PIC18F6X20 PIC18F8X20 0000 -010 0000 -010 uuuu -uuu RCSTA2 PIC18F6X20 PIC18F8X20 0000 000x 0000 000x uuuu uuuu Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition. Shaded cells indicate conditions do not apply for the designated device. Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up). 2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt vector (0008h or 0018h). 3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are updated with the current value of the PC. The STKPTR is modified to point to the next location in the hardware stack. 4: See Table 3-2 for RESET value for specific condition. 5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other Oscillator modes, they are disabled and read `0'. 6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read `0'.
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FIGURE 3-3:
VDD MCLR INTERNAL POR TPWRT PWRT TIME-OUT OST TIME-OUT INTERNAL RESET TOST
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD VIA 1 k RESISTOR)
FIGURE 3-4:
VDD MCLR INTERNAL POR
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
TPWRT TOST
PWRT TIME-OUT OST TIME-OUT INTERNAL RESET
FIGURE 3-5:
VDD MCLR INTERNAL POR
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
TPWRT PWRT TIME-OUT OST TIME-OUT INTERNAL RESET
TOST
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FIGURE 3-6: SLOW RISE TIME (MCLR TIED TO VDD VIA 1 k RESISTOR)
5V VDD MCLR INTERNAL POR TPWRT PWRT TIME-OUT TOST OST TIME-OUT INTERNAL RESET 0V 1V
FIGURE 3-7:
TIME-OUT SEQUENCE ON POR W/ PLL ENABLED (MCLR TIED TO VDD VIA 1 k RESISTOR)
VDD MCLR IINTERNAL POR TPWRT PWRT TIME-OUT OST TIME-OUT TOST TPLL
PLL TIME-OUT INTERNAL RESET
Note:
TOST = 1024 clock cycles. TPLL 2 ms max. First three stages of the PWRT timer.
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4.0 MEMORY ORGANIZATION
4.1.1
There are three memory blocks in PIC18FXX20 devices. They are: * Program Memory * Data RAM * Data EEPROM Data and program memory use separate busses, which allows for concurrent access of these blocks. Additional detailed information for FLASH program memory and Data EEPROM is provided in Section 5.0 and Section 7.0, respectively. In addition to on-chip FLASH, the PIC18F8X20 devices are also capable of accessing external program memory through an external memory bus. Depending on the selected Operating mode (discussed in Section 4.1.1), the controllers may access either internal or external program memory exclusively, or both internal and external memory in selected blocks. Additional information on the External Memory Interface is provided in Section 6.0.
PIC18F8X20 PROGRAM MEMORY MODES
PIC18F8X20 devices differ significantly from their PIC18 predecessors in their utilization of program memory. In addition to available on-chip FLASH program memory, these controllers can also address up to 2 Mbyte of external program memory through external memory interface. There are four distinct Operating modes available to the controllers: * * * * Microprocessor (MP) Microprocessor with Boot Block (MPBB) Extended Microcontroller (EMC) Microcontroller (MC)
The Program Memory mode is determined by setting the two Least Significant bits of the CONFIG3L configuration byte, as shown in Register 4-1. (See also Section 23.1 for additional details on the device configuration bits.) The Program Memory modes operate as follows: * The Microprocessor Mode permits access only to external program memory; the contents of the on-chip FLASH memory are ignored. The 21-bit program counter permits access to a 2-MByte linear program memory space. * The Microprocessor with Boot Block Mode accesses on-chip FLASH memory from addresses 000000h to 0007FFh for PIC18F8520 devices, and from 000000h to 0001FFh for PIC18F8620 and PIC18F8720 devices. Above this, external program memory is accessed all the way up to the 2-MByte limit. Program execution automatically switches between the two memories, as required. * The Microcontroller Mode accesses only on-chip FLASH memory. Attempts to read above the physical limit of the on-chip FLASH (7FFFh for the PIC18F8520, 0FFFFh for the PIC18F8620, 1FFFFh for the PIC18F8720) causes a read of all `0's (a NOP instruction). The Microcontroller mode is also the only Operating mode available to PIC18F6X20 devices. * The Extended Microcontroller Mode allows access to both internal and external program memories as a single block. The device can access its entire on-chip FLASH memory; above this, the device accesses external program memory up to the 2-MByte program space limit. As with Boot Block mode, execution automatically switches between the two memories, as required. In all modes, the microcontroller has complete access to data RAM and EEPROM. Figure 4-2 compares the memory maps of the different Program Memory modes. The differences between on-chip and external memory access limitations are more fully explained in Table 4-1.
4.1
Program Memory Organization
A 21-bit program counter is capable of addressing the 2-Mbyte program memory space. Accessing a location between the physically implemented memory and the 2-Mbyte address will cause a read of all `0's (a NOP instruction). Devices in the PIC18FXX20 family can be divided into three groups, based on program memory size. The PIC18FX520 devices (PIC18F6520 and PIC18F8520) have 32 Kbytes of on-chip FLASH memory, equivalent to 16,384 single word instructions. The PIC18FX620 devices (PIC18F6620 and PIC18F8620) have 64 Kbytes of on-chip FLASH memory, equivalent to 32,768 single word instructions. Finally, the PIC18FX720 devices (PIC18F6720 and PIC18F8720) have 128 Kbytes of on-chip FLASH memory, equivalent to 65,536 single word instructions. For all devices, the RESET vector address is at 0000h, and the interrupt vector addresses are at 0008h and 0018h. The program memory maps for all of the PIC18FXX20 devices are compared in Figure 4-1.
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FIGURE 4-1: INTERNAL PROGRAM MEMORY MAP AND STACK FOR PIC18FXX20 DEVICES
PC<20:0> CALL,RCALL,RETURN RETFIE,RETLW Stack Level 1
* * *
21
Stack Level 31 000000h 000008h 000018h On-Chip FLASH Program Memory 007FFFh 008000h 000000h 000008h 000018h 000000h 000008h 000018h RESET Vector High Priority Interrupt Vector Low Priority Interrupt Vector
On-Chip FLASH Program Memory User Memory Space 01FFFFh 020000h 1FFFFFh 200000h PIC18FX720 (128 Kbyte) Table Read From Yes Yes No Access Yes Table Write To Yes Yes No Access Yes 2003 Microchip Technology Inc. On-Chip FLASH Program Memory
00FFFFh 010000h
Read '0'
Read '0'
Read '0'
1FFFFFh 200000h PIC18FX520 (32 Kbyte) PIC18FX620 (64 Kbyte)
1FFFFFh 200000h
Note:
Size of memory regions not to scale.
TABLE 4-1:
MEMORY ACCESS FOR PIC18F8X20 PROGRAM MEMORY MODES
Internal Program Memory External Program Memory Execution From Yes Yes No Access Yes
Operating Mode
Execution From No Access Yes Yes Yes
Table Read From No Access Yes Yes Yes
Table Write To No Access Yes Yes Yes
Microprocessor Microprocessor w/ Boot Block Microcontroller Extended Microcontroller
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REGISTER 4-1: CONFIG3L CONFIGURATION BYTE
R/P-1 WAIT bit 7 bit 7 WAIT: External Bus Data Wait Enable bit 1 = Wait selections unavailable, device will not wait 0 = Wait programmed by WAIT1 and WAIT0 bits of MEMCOM register (MEMCOM<5:4>) Unimplemented: Read as '0' PM1:PM0: Processor Data Memory Mode Select bits 11 = Microcontroller mode 10 = Microprocessor mode 01 = Microcontroller with Boot Block mode 00 = Extended Microcontroller mode Legend: R = Readable bit - n = Value after erase P = Programmable bit U = Unimplemented bit, read as `0' `1' = Bit is set `0' = Bit is cleared x = Bit is unknown U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- R/P-1 PM1 R/P-1 PM0 bit 0
bit 6-2 bit 1-0
FIGURE 4-2:
MEMORY MAPS FOR PIC18F8X20 PROGRAM MEMORY MODES
Microprocessor with Boot Block Mode (MPBB) 000000h On-Chip Program Memory Boot Boot+1 Boundary Boundary+1 Microcontroller Mode (MC) 000000h On-Chip Program Memory Boundary Boundary+1 000000h On-Chip Program Memory Extended Microcontroller Mode (EMC)
Microprocessor Mode (MP) 000000h
On-Chip Program Memory (No
access)
Program Space Execution
External Program Memory
External Program Memory
Reads `0's
External Program Memory
1FFFFFh External Memory On-Chip FLASH
1FFFFFh External Memory On-Chip FLASH
1FFFFFh On-Chip FLASH
1FFFFFh External Memory On-Chip FLASH
Boundary Values for Microprocessor with Boot Block, Microcontroller and Extended Microcontroller modes(1) Device PIC18F6520 PIC18F6620 PIC18F6720 PIC18F8520 PIC18F8620 PIC18F8720 Note 1: Boot 0007FFh 0001FFh 0001FFh 0007FFh 0001FFh 0001FFh Boot+1 000800h 000200h 000200h 000800h 000200h 000200h Boundary 007FFFh 00FFFFh 01FFFFh 007FFFh 00FFFFh 01FFFFh Boundary+1 008000h 010000h 020000h 008000h 010000h 020000h Available Memory Mode(s) MC MC MC MP, MPBB, MC, EMC MP, MPBB, MC, EMC MP, MPBB, MC, EMC
PIC18F6X20 devices are included here for completeness, to show the boundaries of their boot blocks and program memory spaces.
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4.2 Return Address Stack
4.2.2
The return address stack allows any combination of up to 31 program calls and interrupts to occur. The PC (Program Counter) is pushed onto the stack when a CALL or RCALL instruction is executed, or an interrupt is acknowledged. The PC value is pulled off the stack on a RETURN, RETLW, or a RETFIE instruction. PCLATU and PCLATH are not affected by any of the RETURN or CALL instructions. The stack operates as a 31-word by 21-bit RAM and a 5-bit stack pointer, with the stack pointer initialized to 00000b after all RESETS. There is no RAM associated with stack pointer 00000b. This is only a RESET value. During a CALL type instruction, causing a push onto the stack, the stack pointer is first incremented and the RAM location pointed to by the stack pointer is written with the contents of the PC. During a RETURN type instruction, causing a pop from the stack, the contents of the RAM location pointed to by the STKPTR are transferred to the PC and then the stack pointer is decremented. The stack space is not part of either program or data space. The stack pointer is readable and writable, and the address on the top of the stack is readable and writable through SFR registers. Data can also be pushed to, or popped from, the stack using the top-of-stack SFRs. Status bits indicate if the stack pointer is at, or beyond the 31 levels provided.
RETURN STACK POINTER (STKPTR)
The STKPTR register contains the stack pointer value, the STKFUL (stack full) status bit, and the STKUNF (stack underflow) status bits. Register 4-2 shows the STKPTR register. The value of the stack pointer can be 0 through 31. The stack pointer increments when values are pushed onto the stack and decrements when values are popped off the stack. At RESET, the stack pointer value will be `0'. The user may read and write the stack pointer value. This feature can be used by a Real-Time Operating System for return stack maintenance. After the PC is pushed onto the stack 31 times (without popping any values off the stack), the STKFUL bit is set. The STKFUL bit can only be cleared in software or by a POR. The action that takes place when the stack becomes full, depends on the state of the STVREN (Stack Overflow Reset Enable) configuration bit. Refer to Section 24.0 for a description of the device configuration bits. If STVREN is set (default), the 31st push will push the (PC + 2) value onto the stack, set the STKFUL bit, and reset the device. The STKFUL bit will remain set and the stack pointer will be set to `0'. If STVREN is cleared, the STKFUL bit will be set on the 31st push and the stack pointer will increment to 31. Any additional pushes will not overwrite the 31st push, and STKPTR will remain at 31. When the stack has been popped enough times to unload the stack, the next pop will return a value of zero to the PC and sets the STKUNF bit, while the stack pointer remains at `0'. The STKUNF bit will remain set until cleared in software or a POR occurs. Note: Returning a value of zero to the PC on an underflow has the effect of vectoring the program to the RESET vector, where the stack conditions can be verified and appropriate actions can be taken.
4.2.1
TOP-OF-STACK ACCESS
The top of the stack is readable and writable. Three register locations, TOSU, TOSH and TOSL hold the contents of the stack location pointed to by the STKPTR register. This allows users to implement a software stack if necessary. After a CALL, RCALL or interrupt, the software can read the pushed value by reading the TOSU, TOSH and TOSL registers. These values can be placed on a user defined software stack. At return time, the software can replace the TOSU, TOSH and TOSL and do a return. The user must disable the global interrupt enable bits during this time to prevent inadvertent stack operations.
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REGISTER 4-2: STKPTR REGISTER
R/C-0 bit 7 bit 7 STKFUL: Stack Full Flag bit 1 = Stack became full or overflowed 0 = Stack has not become full or overflowed STKUNF: Stack Underflow Flag bit 1 = Stack underflow occurred 0 = Stack underflow did not occur Unimplemented: Read as '0' SP4:SP0: Stack Pointer Location bits Note 1: Bit 7 and bit 6 can only be cleared in user software or by a POR. Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/C-0 U-0 -- R/W-0 SP4 R/W-0 SP3 R/W-0 SP2 R/W-0 SP1 R/W-0 SP0 bit 0 STKFUL(1) STKUNF(1)
bit 6
bit 5 bit 4-0
FIGURE 4-3:
RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
Return Address Stack 11111 11110 11101 TOSU 0x00 TOSH 0x1A TOSL 0x34 00011 Top-of-Stack 0x001A34 00010 0x000D58 00001 00000
STKPTR<4:0> 00010
4.2.3
PUSH AND POP INSTRUCTIONS
4.2.4
STACK FULL/UNDERFLOW RESETS
Since the Top-of-Stack (TOS) is readable and writable, the ability to push values onto the stack and pull values off the stack, without disturbing normal program execution, is a desirable option. To push the current PC value onto the stack, a PUSH instruction can be executed. This will increment the stack pointer and load the current PC value onto the stack. TOSU, TOSH and TOSL can then be modified to place a return address on the stack. The ability to pull the TOS value off of the stack and replace it with the value that was previously pushed onto the stack, without disturbing normal execution, is achieved by using the POP instruction. The POP instruction discards the current TOS by decrementing the stack pointer. The previous value pushed onto the stack then becomes the TOS value.
These RESETS are enabled by programming the STVREN configuration bit. When the STVREN bit is disabled, a full or underflow condition will set the appropriate STKFUL or STKUNF bit, but not cause a device RESET. When the STVREN bit is enabled, a full or underflow condition will set the appropriate STKFUL or STKUNF bit and then cause a device RESET. The STKFUL or STKUNF bits are only cleared by the user software or a POR Reset.
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PIC18FXX20
4.3 Fast Register Stack 4.4 PCL, PCLATH and PCLATU
A "fast interrupt return" option is available for interrupts. A Fast Register Stack is provided for the STATUS, WREG and BSR registers and is only one in depth. The stack is not readable or writable and is loaded with the current value of the corresponding register when the processor vectors for an interrupt. The values in the registers are then loaded back into the working registers, if the FAST RETURN instruction is used to return from the interrupt. A low or high priority interrupt source will push values into the stack registers. If both low and high priority interrupts are enabled, the stack registers cannot be used reliably for low priority interrupts. If a high priority interrupt occurs while servicing a low priority interrupt, the stack register values stored by the low priority interrupt will be overwritten. If high priority interrupts are not disabled during low priority interrupts, users must save the key registers in software during a low priority interrupt. If no interrupts are used, the fast register stack can be used to restore the STATUS, WREG and BSR registers at the end of a subroutine call. To use the fast register stack for a subroutine call, a FAST CALL instruction must be executed. Example 4-1 shows a source code example that uses the fast register stack. The program counter (PC) specifies the address of the instruction to fetch for execution. The PC is 21-bits wide. The low byte is called the PCL register; this register is readable and writable. The high byte is called the PCH register. This register contains the PC<15:8> bits and is not directly readable or writable; updates to the PCH register may be performed through the PCLATH register. The upper byte is called PCU. This register contains the PC<20:16> bits and is not directly readable or writable; updates to the PCU register may be performed through the PCLATU register. The PC addresses bytes in the program memory. To prevent the PC from becoming misaligned with word instructions, the LSB of the PCL is fixed to a value of `0'. The PC increments by 2 to address sequential instructions in the program memory. The CALL, RCALL, GOTO and program branch instructions write to the program counter directly. For these instructions, the contents of PCLATH and PCLATU are not transferred to the program counter. The contents of PCLATH and PCLATU will be transferred to the program counter by an operation that writes PCL. Similarly, the upper two bytes of the program counter will be transferred to PCLATH and PCLATU by an operation that reads PCL. This is useful for computed offsets to the PC (see Section 4.8.1).
EXAMPLE 4-1:
CALL SUB1, FAST
FAST REGISTER STACK CODE EXAMPLE
;STATUS, WREG, BSR ;SAVED IN FAST REGISTER ;STACK
4.5
Clocking Scheme/Instruction Cycle
* * SUB1 * * * RETURN FAST
;RESTORE VALUES SAVED ;IN FAST REGISTER STACK
The clock input (from OSC1) is internally divided by four to generate four non-overlapping quadrature clocks, namely Q1, Q2, Q3 and Q4. Internally, the program counter (PC) is incremented every Q1, the instruction is fetched from the program memory and latched into the instruction register in Q4. The instruction is decoded and executed during the following Q1 through Q4. The clocks and instruction execution flow are shown in Figure 4-4.
FIGURE 4-4:
OSC1 Q1 Q2 Q3 Q4 PC OSC2/CLKO (RC mode)
CLOCK/INSTRUCTION CYCLE
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Internal Phase Clock PC Execute INST (PC-2) Fetch INST (PC) PC+2 PC+4
Execute INST (PC) Fetch INST (PC+2)
Execute INST (PC+2) Fetch INST (PC+4)
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4.6 Instruction Flow/Pipelining
An "Instruction Cycle" consists of four Q cycles (Q1, Q2, Q3 and Q4). The instruction fetch and execute are pipelined, such that fetch takes one instruction cycle, while decode and execute takes another instruction cycle. However, due to the pipelining, each instruction effectively executes in one cycle. If an instruction causes the program counter to change (e.g., GOTO) then two cycles are required to complete the instruction (Example 4-2). A fetch cycle begins with the program counter (PC) incrementing in Q1. In the execution cycle, the fetched instruction is latched into the "Instruction Register" (IR) in cycle Q1. This instruction is then decoded and executed during the Q2, Q3, and Q4 cycles. Data memory is read during Q2 (operand read) and written during Q4 (destination write).
EXAMPLE 4-2:
INSTRUCTION PIPELINE FLOW
TCY0 TCY1 Execute 1 Fetch 2 Execute 2 Fetch 3 Execute 3 Fetch 4 Flush (NOP) Fetch SUB_1 Execute SUB_1 TCY2 TCY3 TCY4 TCY5
1. MOVLW 55h 2. MOVWF PORTB 3. BRA 4. BSF SUB_1
Fetch 1
PORTA, BIT3 (Forced NOP)
5. Instruction @ address SUB_1
All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction is "flushed" from the pipeline, while the new instruction is being fetched and then executed.
4.7
Instructions in Program Memory
The program memory is addressed in bytes. Instructions are stored as two bytes or four bytes in program memory. The Least Significant Byte of an instruction word is always stored in a program memory location with an even address (LSB = 0). Figure 4-5 shows an example of how instruction words are stored in the program memory. To maintain alignment with instruction boundaries, the PC increments in steps of 2 and the LSB will always read `0' (see Section 4.4). The CALL and GOTO instructions have an absolute program memory address embedded into the instruction. Since instructions are always stored on word bound-
aries, the data contained in the instruction is a word address. The word address is written to PC<20:1>, which accesses the desired byte address in program memory. Instruction #2 in Figure 4-5 shows how the instruction "GOTO 000006h" is encoded in the program memory. Program branch instructions, which encode a relative address offset, operate in the same manner. The offset value stored in a branch instruction represents the number of single word instructions that the PC will be offset by. Section 24.0 provides further details of the instruction set.
FIGURE 4-5:
INSTRUCTIONS IN PROGRAM MEMORY
LSB = 1 LSB = 0 Word Address 000000h 000002h 000004h 000006h 000008h 00000Ah 00000Ch 00000Eh 000010h 000012h 000014h
Program Memory Byte Locations
Instruction 1: Instruction 2: Instruction 3:
MOVLW GOTO MOVFF
055h 000006h 123h, 456h
0Fh EFh F0h C1h F4h
55h 03h 00h 23h 56h
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4.7.1 TWO-WORD INSTRUCTIONS
The PIC18FXX20 devices have four two-word instructions: MOVFF, CALL, GOTO and LFSR. The second word of these instructions has the 4 MSBs set to `1's and is a special kind of NOP instruction. The lower 12 bits of the second word contain data to be used by the instruction. If the first word of the instruction is executed, the data in the second word is accessed. If the second word of the instruction is executed by itself (first word was skipped), it will execute as a NOP. This action is necessary when the two-word instruction is preceded by a conditional instruction that changes the PC. A program example that demonstrates this concept is shown in Example 4-3. Refer to Section 19.0 for further details of the instruction set.
EXAMPLE 4-3:
CASE 1: Object Code
TWO-WORD INSTRUCTIONS
Source Code TSTFSZ MOVFF REG1 ; is RAM location 0?
0110 0110 0000 0000 1100 0001 0010 0011 1111 0100 0101 0110 0010 0100 0000 0000 CASE 2: Object Code 0110 0110 0000 0000 1100 0001 0010 0011 1111 0100 0101 0110 0010 0100 0000 0000
REG1, REG2 ; No, execute 2-word instruction ; 2nd operand holds address of REG2
ADDWF
REG3
; continue code
Source Code TSTFSZ MOVFF REG1 ; is RAM location 0?
REG1, REG2 ; Yes ; 2nd operand becomes NOP
ADDWF
REG3
; continue code
4.8
Lookup Tables
4.8.2
TABLE READS/TABLE WRITES
Lookup tables are implemented two ways. These are: * Computed GOTO * Table Reads
A better method of storing data in program memory allows 2 bytes of data to be stored in each instruction location. Lookup table data may be stored 2 bytes per program word by using table reads and writes. The table pointer (TBLPTR) specifies the byte address and the table latch (TABLAT) contains the data that is read from, or written to program memory. Data is transferred to/from program memory, one byte at a time. A description of the Table Read/Table Write operation is shown in Section 5.0.
4.8.1
COMPUTED GOTO
A computed GOTO is accomplished by adding an offset to the program counter (ADDWF PCL). A lookup table can be formed with an ADDWF PCL instruction and a group of RETLW 0xnn instructions. WREG is loaded with an offset into the table before executing a call to that table. The first instruction of the called routine is the ADDWF PCL instruction. The next instruction executed will be one of the RETLW 0xnn instructions, that returns the value 0xnn to the calling function. The offset value (value in WREG) specifies the number of bytes that the program counter should advance. In this method, only one data byte may be stored in each instruction location and room on the return address stack is required.
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4.9 Data Memory Organization
4.9.1
The data memory is implemented as static RAM. Each register in the data memory has a 12-bit address, allowing up to 4096 bytes of data memory. The data memory map is in turn divided into 16 banks of 256 bytes each. The lower 4 bits of the Bank Select Register (BSR<3:0>) select which bank will be accessed. The upper 4 bits for the BSR are not implemented. The data memory space contains both Special Function Registers (SFR) and General Purpose Registers (GPR). The SFRs are used for control and status of the controller and peripheral functions, while GPRs are used for data storage and scratch pad operations in the user's application. The SFRs start at the last location of Bank 15 (0FFFh) and extend downwards. Any remaining space beyond the SFRs in the Bank may be implemented as GPRs. GPRs start at the first location of Bank 0 and grow upwards. Any read of an unimplemented location will read as `0's. PIC18FX520 devices have 2048 bytes of data RAM, extending from Bank 0 to Bank 7 (000h through 7FFh). PIC18FX620 and PIC18FX720 devices have 3840 bytes of data RAM, extending from Bank 0 to Bank 14 (000h through EFFh). The organization of the data memory space for these devices is shown in Figure 4-6 and Figure 4-7. The entire data memory may be accessed directly or indirectly. Direct addressing may require the use of the BSR register. Indirect addressing requires the use of a File Select Register (FSRn) and a corresponding Indirect File Operand (INDFn). Each FSR holds a 12-bit address value that can be used to access any location in the Data Memory map without banking. The instruction set and architecture allow operations across all banks. This may be accomplished by indirect addressing, or by the use of the MOVFF instruction. The MOVFF instruction is a two-word/two-cycle instruction that moves a value from one register to another. To ensure that commonly used registers (SFRs and select GPRs) can be accessed in a single cycle, regardless of the current BSR values, an Access Bank is implemented. A segment of Bank 0 and a segment of Bank 15 comprise the Access RAM. Section 4.10 provides a detailed description of the Access RAM.
GENERAL PURPOSE REGISTER FILE
The register file can be accessed either directly or indirectly. Indirect addressing operates using a File Select Register and corresponding Indirect File Operand. The operation of indirect addressing is shown in Section 4.12. Enhanced MCU devices may have banked memory in the GPR area. GPRs are not initialized by a Power-on Reset and are unchanged on all other RESETS. Data RAM is available for use as general purpose registers by all instructions. The top section of Bank 15 (F60h to FFFh) contains SFRs. All other banks of data memory contain GPR registers, starting with Bank 0.
4.9.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers (SFRs) are registers used by the CPU and Peripheral Modules for controlling the desired operation of the device. These registers are implemented as static RAM. A list of these registers is given in Table 4-2 and Table 4-3. The SFRs can be classified into two sets: those associated with the "core" function and those related to the peripheral functions. Those registers related to the "core" are described in this section, while those related to the operation of the peripheral features are described in the section of that peripheral feature. The SFRs are typically distributed among the peripherals whose functions they control. The unused SFR locations are unimplemented and read as '0's. The addresses for the SFRs are listed in Table 4-2.
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FIGURE 4-6:
BSR<3:0> = 0000 00h Bank 0 FFh 00h Bank 1 Bank 2 FFh 00h FFh 00h Bank 3 to Bank 6 FFh 00h Bank 7 FFh = 1000 GPRs 7FFh 800h GPRs Access Bank 6FFh 700h 00h 5Fh Access RAM High 60h (SFRs) FFh Access RAM Low
DATA MEMORY MAP FOR PIC18FX520 DEVICES
Data Memory Map Access RAM GPRs GPRs 1FFh 200h GPRs 2FFh 300h 000h 05Fh 060h 0FFh 100h
= 0001 = 0010 = 0011
* * *
= 0110 = 0111
* * *
Bank 8 to Bank 14
Unused, Read as `0'
= 1110 00h Bank 15 FFh When a = 1, the BSR is used to specify the RAM location that the instruction uses. EFFh F00h F5Fh F60h FFFh
When a = 0, the BSR is ignored and the Access Bank is used. The first 128 bytes are General Purpose RAM (from Bank 0). The second 128 bytes are Special Function Registers (from Bank 15).
= 1111
Unused SFRs
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FIGURE 4-7:
BSR<3:0> = 0000 00h Bank 0 FFh 00h Bank 1 Bank 2 FFh 00h FFh 00h FFh = 0100 Bank 4 GPRs 4FFh 500h
DATA MEMORY MAP FOR PIC18FX620 AND PIC18FX720 DEVICES
Data Memory Map Access RAM GPRs GPRs 1FFh 200h GPRs 2FFh 300h GPRs 3FFh 400h Access Bank 00h 5Fh Access RAM High 60h (SFRs) FFh Access RAM Low 000h 05Fh 060h 0FFh 100h
= 0001 = 0010
= 0011
Bank 3
= 0101
* * *
Bank 5 to Bank 13
GPRs When a = 0, the BSR is ignored and the Access Bank is used. The first 128 bytes are General Purpose RAM (from Bank 0). The second 128 bytes are Special Function Registers (from Bank 15).
= 1101 00h Bank 14 FFh 00h Bank 15 FFh When a = 1, the BSR is used to specify the RAM location that the instruction uses. GPRs Unused SFRs EFFh F00h F5Fh F60h FFFh DFFh E00h
= 1110
= 1111
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TABLE 4-2:
Address FFFh FFEh FFDh FFCh FFBh FFAh FF9h FF8h FF7h FF6h FF5h FF4h FF3h FF2h FF1h FF0h FEFh FEEh FECh FEBh FEAh FE9h FE8h FE7h
SPECIAL FUNCTION REGISTER MAP
Name TOSU TOSH TOSL STKPTR PCLATU PCLATH PCL TBLPTRU TBLPTRH TBLPTRL TABLAT PRODH PRODL INTCON INTCON2 INTCON3 INDF0(3) POSTINC0(3) PREINC0(3) PLUSW0(3) FSR0H FSR0L WREG INDF1(3) Address FDFh Name INDF2(3)
(3)
Address FBFh FBEh FBDh FBCh FBBh FBAh FB9h FB8h FB7h FB6h FB5h FB4h FB3h FB2h FB1h FB0h FAFh FAEh FADh FACh FABh FAAh FA9h FA8h FA7h FA6h FA5h FA4h FA3h FA2h FA1h FA0h
Name CCPR1H CCPR1L CCP1CON CCPR2H CCPR2L CCP2CON CCPR3H CCPR3L CCP3CON --
(1)
Address F9Fh F9Eh F9Dh F9Bh F9Ah F99h F98h F97h F96h F95h F94h F93h F92h F91h F90h F8Fh F8Eh F8Dh F8Ch F8Bh F8Ah F89h F88h F87h F86h F85h F84h F83h F82h F81h F80h
Name IPR1 PIR1 PIE1 --(1) TRISJ(2) TRISH(2) TRISG TRISF TRISE TRISD TRISC TRISB TRISA LATJ(2) LATH(2) LATG LATF LATE LATD LATC LATB LATA PORTJ(2) PORTH(2) PORTG PORTF PORTE PORTD PORTC PORTB PORTA
FDEh POSTINC2 FDCh FDBh FDAh FD9h FD8h FD7h FD6h FD5h FD4h FD3h FD2h FD1h FD0h FCFh FCEh FCDh FCCh FCBh FCAh FC9h FC8h FC7h FC6h FC5h FC4h FC3h FC2h FC1h FC0h PREINC2 PLUSW2 FSR2L STATUS TMR0H TMR0L T0CON --(1) FSR2H
FDDh POSTDEC2(3)
(3) (3)
F9Ch MEMCON(2)
CVRCON CMCON TMR3H TMR3L T3CON PSPCON SPBRG1 RCREG1 TXREG1 TXSTA1 RCSTA1 EEADRH EEADR EEDATA EECON2 EECON1 IPR3 PIR3 PIE3 IPR2 PIR2 PIE2
OSCCON LVDCON WDTCON RCON TMR1H TMR1L T1CON TMR2 PR2 T2CON SSPBUF SSPADD SSPSTAT SSPCON1 SSPCON2 ADRESH ADRESL ADCON0 ADCON1 ADCON2
FEDh POSTDEC0(3)
FE6h POSTINC1(3) FE5h POSTDEC1(3) FE4h FE3h FE2h FE1h FE0h PREINC1(3) PLUSW1(3) FSR1H FSR1L BSR
Note 1: Unimplemented registers are read as `0'. 2: This register is not available on PIC18FX520 and PIC18F6X20 devices. 3: This is not a physical register.
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TABLE 4-2:
Address F7Fh F7Eh F7Dh F7Ch F7Bh F7Ah F79h F78h F77h F76h F75h F74h F73h F72h F71h F70h F6Fh F6Eh F6Dh F6Ch F6Bh F6Ah F69h F68h F67h F66h F65h F64h F63h F62h F61h F60h
SPECIAL FUNCTION REGISTER MAP (CONTINUED)
Name --(1) --(1) -- -- --
(1)
Address F5Fh F5Eh F5Dh F5Ch F5Bh F5Ah F59h F58h F57h F56h F55h F54h F53h F52h F51h F50h F4Fh F4Eh F4Dh F4Ch F4Bh F4Ah F49h F48h F47h F46h F45h F44h F43h F42h F41h F40h
Name --(1) --(1) -- -- --
(1)
Address F3Fh F3Eh F3Dh F3Ch F3Bh F3Ah F39h F38h F37h F36h F35h F34h F33h F32h F31h F30h F2Fh F2Eh F2Dh F2Ch F2Bh F2Ah F29h F28h F27h F26h F25h F24h F23h F22h F21h F20h
Name --(1) --(1) -- -- -- -- --
(1)
Address F1Fh F1Eh F1Dh F1Ch F1Bh F1Ah F19h F18h F17h F16h F15h F14h F13h F12h F11h F10h F0Fh F0Eh F0Dh F0Ch F0Bh F0Ah F09h F08h F07h F06h F05h F04h F03h F02h F01h F00h
Name --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1)
--(1)
(1)
--(1)
(1)
--(1)
(1)
--(1)
(1)
--(1)
(1)
--(1)
(1)
TMR4 PR4 T4CON CCPR4H CCPR4L CCP4CON CCPR5H CCPR5L CCP5CON SPBRG2 RCREG2 TXREG2 TXSTA2 RCSTA2 --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1)
--(1) -- --
(1)
--(1)
(1)
--(1)
(1)
--(1)
(1)
--(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1)
--(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1) --(1)
Note 1: Unimplemented registers are read as `0'. 2: This register is not available on PIC18F6X20 devices. 3: This is not a physical register.
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TABLE 4-3:
File Name TOSU TOSH TOSL STKPTR PCLATU PCLATH PCL TBLPTRU TBLPTRH TBLPTRL TABLAT PRODH PRODL INTCON INTCON2 INTCON3 INDF0 POSTINC0
REGISTER FILE SUMMARY
Bit 7 -- Bit 6 -- Bit 5 -- Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Details on page:
Top-of-Stack Upper Byte (TOS<20:16>)
---0 0000 32, 42 0000 0000 32, 42 0000 0000 32, 42
Top-of-Stack High Byte (TOS<15:8>) Top-of-Stack Low Byte (TOS<7:0>) STKFUL -- STKUNF -- -- bit21 Return Stack Pointer Holding Register for PC<20:16>
00-0 0000 32, 43 --10 0000 32, 44 0000 0000 32, 44 0000 0000 32, 44
Holding Register for PC<15:8> PC Low Byte (PC<7:0>) -- -- bit21(2) Program Memory Table Pointer Upper Byte (TBLPTR<20:16>) Program Memory Table Pointer High Byte (TBLPTR<15:8>) Program Memory Table Pointer Low Byte (TBLPTR<7:0>) Program Memory Table Latch Product Register High Byte Product Register Low Byte GIE/GIEH PEIE/GIEL RBPU INT2IP INTEDG0 INT1IP TMR0IE INTEDG1 INT3IE INT0IE INTEDG2 INT2IE RBIE INTEDG3 INT1IE TMR0IF TMR0IP INT3IF INT0IF INT3IP INT2IF RBIF RBIP INT1IF
--00 0000 32, 64 0000 0000 32, 64 0000 0000 32, 64 0000 0000 32, 64 xxxx xxxx 32, 85 xxxx xxxx 32, 85 0000 0000 32, 89 1111 1111 32, 90 1100 0000 32, 91 n/a n/a n/a n/a n/a 57 57 57 57 57
Uses contents of FSR0 to address data memory - value of FSR0 not changed (not a physical register) Uses contents of FSR0 to address data memory - value of FSR0 post-incremented (not a physical register)
POSTDEC0 Uses contents of FSR0 to address data memory - value of FSR0 post-decremented (not a physical register) PREINC0 PLUSW0 FSR0H FSR0L WREG INDF1 POSTINC1 Uses contents of FSR0 to address data memory - value of FSR0 pre-incremented (not a physical register) Uses contents of FSR0 to address data memory - value of FSR0 pre-incremented (not a physical register) - value of FSR0 offset by value in WREG -- -- -- -- Indirect Data Memory Address Pointer 0 Low Byte Working Register Uses contents of FSR1 to address data memory - value of FSR1 not changed (not a physical register) Uses contents of FSR1 to address data memory - value of FSR1 post-incremented (not a physical register)
Indirect Data Memory Address Pointer 0 High Byte ---- 0000 32, 57 xxxx xxxx 32, 57 xxxx xxxx n/a n/a n/a n/a n/a 32 57 57 57 57 57
POSTDEC1 Uses contents of FSR1 to address data memory - value of FSR1 post-decremented (not a physical register) PREINC1 PLUSW1 FSR1H FSR1L BSR INDF2 POSTINC2 POSTDEC2 Uses contents of FSR1 to address data memory - value of FSR1 pre-incremented (not a physical register) Uses contents of FSR1 to address data memory - value of FSR1 pre-incremented (not a physical register) - value of FSR1 offset by value in WREG -- -- -- -- -- -- -- -- Indirect Data Memory Address Pointer 1 Low Byte Bank Select Register Uses contents of FSR2 to address data memory - value of FSR2 not changed (not a physical register) Uses contents of FSR2 to address data memory - value of FSR2 post-incremented (not a physical register) Uses contents of FSR2 to address data memory - value of FSR2 post-decremented (not a physical register)
Indirect Data Memory Address Pointer 1 High Byte ---- 0000 33, 57 xxxx xxxx 33, 57 ---- 0000 33, 56 n/a n/a n/a 57 57 57
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes. 2: Bit 21 of the TBLPTRU allows access to the device configuration bits. 3: These registers are unused on PIC18F6X20 devices; always maintain these clear.
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TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR n/a n/a Details on page: 57 57
PREINC2 PLUSW2 FSR2H FSR2L STATUS TMR0H TMR0L T0CON OSCCON LVDCON WDTCON RCON TMR1H TMR1L T1CON TMR2 PR2 T2CON SSPBUF SSPADD SSPSTAT SSPCON1 SSPCON2 ADRESH ADRESL ADCON0 ADCON1 ADCON2 CCPR1H CCPR1L CCP1CON CCPR2H CCPR2L CCP2CON CCPR3H CCPR3L CCP3CON CVRCON
Uses contents of FSR2 to address data memory - value of FSR2 pre-incremented (not a physical register) Uses contents of FSR2 to address data memory - value of FSR2 pre-incremented (not a physical register) - value of FSR2 offset by value in WREG -- -- -- -- -- -- -- N Indirect Data Memory Address Pointer 2 Low Byte OV Z DC C Timer0 Register High Byte Timer0 Register Low Byte TMR0ON -- -- -- IPEN T08BIT -- -- -- -- T0CS -- IRVST -- -- T0SE -- LVDEN -- RI PSA -- LVDL3 -- TO T0PS2 -- LVDL2 -- PD T0PS1 -- LVDL1 -- POR T0PS0 SCS LVDL0 SWDTE BOR
Indirect Data Memory Address Pointer 2 High Byte ---- 0000 33, 57 xxxx xxxx 33, 57 ---x xxxx 33, 59 0000 0000 33, 133 xxxx xxxx 33, 133 1111 1111 33, 131 ---- ---0 25, 33 --00 0101 33, 235 ---- ---0 33, 250 0--1 11qq 33, 60, 101 xxxx xxxx 33, 135 xxxx xxxx 33, 135
Timer1 Register High Byte Timer1 Register Low Byte RD16 Timer2 Register Timer2 Period Register -- T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 SSP Receive Buffer/Transmit Register SSP Address Register in I2C Slave mode. SSP Baud Rate Reload Register in I2C Master mode. SMP WCOL GCEN CKE SSPOV ACKSTAT D/A SSPEN ACKDT P CKP ACKEN S SSPM3 RCEN R/W SSPM2 PEN UA SSPM1 RSEN BF SSPM0 SEN -- T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS
TMR1ON 0-00 0000 33, 135 0000 0000 33, 141 1111 1111 33, 142 T2CKPS0 -000 0000 33, 141 xxxx xxxx 33, 157 0000 0000 33, 166 0000 0000 33, 158 0000 0000 33, 159 0000 0000 33, 169 xxxx xxxx 34, 221 xxxx xxxx 34, 221
A/D Result Register High Byte A/D Result Register Low Byte -- -- ADFM -- -- -- CHS3 VCFG1 -- CHS2 VCFG0 -- CHS1 PCFG3 -- CHS0 PCFG2 ADCS2 GO/DONE PCFG1 ADCS1 ADON PCFG0 ADCS0
--00 0000 34, 213 --00 0000 34, 214 0--- -000 34, 215 xxxx xxxx xxxx xxxx 153, 155 153, 155
Capture/Compare/PWM Register1 High Byte Capture/Compare/PWM Register1 Low Byte -- -- DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1
CCP1M0 --00 0000 34, 149 xxxx xxxx 34, 153 xxxx xxxx 34, 153
Capture/Compare/PWM Register2 High Byte Capture/Compare/PWM Register2 Low Byte -- -- DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 Capture/Compare/PWM Register3 High Byte Capture/Compare/PWM Register3 Low Byte -- CVREN -- CVROE DC3B1 CVRR DC3B0 CVRSS CCP3M3 CVR3 CCP3M2 CVR2 CCP3M1 CVR1 CVR0
CCP2M0 --00 0000 34, 149 xxxx xxxx 34, 153 xxxx xxxx 34, 153 CCP3M0 --00 0000 34, 149 0000 0000 34, 229
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes. 2: Bit 21 of the TBLPTRU allows access to the device configuration bits. 3: These registers are unused on PIC18F6X20 devices; always maintain these clear.
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TABLE 4-3:
File Name CMCON TMR3H TMR3L T3CON PSPCON SPBRG1 RCREG1 TXREG1 TXSTA1 RCSTA1 EEADRH EEADR EEDATA EECON2 EECON1 IPR3 PIR3 PIE3 IPR2 PIR2 PIE2 IPR1 PIR1 PIE1 MEMCON(3) TRISJ(3) TRISH(3) TRISG TRISF TRISE TRISD TRISC TRISB TRISA LATJ(3) LATH LATF LATE LATD LATC LATB
(3)
REGISTER FILE SUMMARY (CONTINUED)
Bit 7 C2OUT Bit 6 C1OUT Bit 5 C2INV Bit 4 C1INV Bit 3 CIS Bit 2 CM2 Bit 1 CM1 Bit 0 CM0 Value on POR, BOR Details on page:
0000 0000 34, 223 xxxx xxxx 34, 143 xxxx xxxx 34, 143
Timer3 Register High Byte Timer3 Register Low Byte RD16 IBF T3CCP2 OBF T3CKPS1 IBOV T3CKPS0 PSPMODE T3CCP1 -- T3SYNC -- TMR3CS -- --
TMR3ON 0000 0000 34, 143 0000 ---- 34, 129 0000 0000 34, 205 0000 0000 34, 207 0000 0000 34, 205
USART1 Baud Rate Generator USART1 Receive Register USART1 Transmit Register CSRC SPEN -- TX9 RX9 -- TXEN SREN -- SYNC CREN -- -- ADDEN -- BRGH FERR -- TRMT OERR TX9D RX9D
0000 -010 34, 198 0000 000x 34, 199 ---- --00 34, 83 0000 0000 34, 83 0000 0000 34, 83 ---- ---- 34, 83
EE Adr Register High
Data EEPROM Address Register Data EEPROM Data Register Data EEPROM Control Register 2 (not a physical register) EEPGD -- -- -- -- -- -- PSPIP PSPIF PSPIE EBDIS CFGS -- -- -- CMIP CMIF CMIE ADIP ADIF ADIE -- -- RC2IP RC2IF RC2IE -- -- -- RCIP RCIF RCIE WAIT1 FREE TX2IP TX2IF TX2IE EEIP EEIF EEIE TXIP TXIF TXIE WAIT0 WRERR TMR4IP TMR4IF TMR4IE BCLIP BCLIF BCLIE SSPIP SSPIF SSPIE -- WREN CCP5IP CCP5IF CCP5IE LVDIP LVDIF LVDIE CCP1IP CCP1IF CCP1IE -- WR CCP4IP CCP4IF CCP4IE TMR3IP TMR3IF TMR3IE TMR2IP TMR2IF TMR2IE WM1 RD CCP3IP CCP3IF CCP3IE CCP2IP CCP2IF CCP2IE TMR1IP TMR1IF TMR1IE WM0
00-0 x000 34, 80 --11 1111 35, 100 --00 0000 35, 94 --00 0000 35, 97 -1-1 1111 35, 99 -0-0 0000 35, 93 -0-0 0000 35, 96 0111 1111 35, 98 0000 0000 35, 92 0000 0000 35, 95 0-00 --00 35, 71 1111 1111 35, 127 1111 1111 35, 124 ---1 1111 35, 121 1111 1111 35, 119 1111 1111 35, 116 1111 1111 35, 113 1111 1111 35, 109 1111 1111 35, 106 -111 1111 35, 103 xxxx xxxx 35, 127 xxxx xxxx 35, 124 ---x xxxx 35, 121 xxxx xxxx 35, 119 xxxx xxxx 35, 116 xxxx xxxx 35, 111 xxxx xxxx 35, 109 xxxx xxxx 35, 106
Data Direction Control Register for PORTJ Data Direction Control Register for PORTH -- -- -- Data Direction Control Register for PORTG Data Direction Control Register for PORTF Data Direction Control Register for PORTE Data Direction Control Register for PORTD Data Direction Control Register for PORTC Data Direction Control Register for PORTB -- TRISA6(1) Data Direction Control Register for PORTA Read PORTJ Data Latch, Write PORTJ Data Latch Read PORTH Data Latch, Write PORTH Data Latch -- -- -- Read PORTG Data Latch, Write PORTG Data Latch Read PORTF Data Latch, Write PORTF Data Latch Read PORTE Data Latch, Write PORTE Data Latch Read PORTD Data Latch, Write PORTD Data Latch Read PORTC Data Latch, Write PORTC Data Latch Read PORTB Data Latch, Write PORTB Data Latch
LATG
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes. 2: Bit 21 of the TBLPTRU allows access to the device configuration bits. 3: These registers are unused on PIC18F6X20 devices; always maintain these clear.
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TABLE 4-3:
File Name LATA PORTJ(3) PORTH(3) PORTG PORTF PORTE PORTD PORTC PORTB PORTA TMR4 PR4 T4CON CCPR4H CCPR4L CCP4CON CCPR5H CCPR5L CCP5CON SPBRG2 RCREG2 TXREG2 TXSTA2 RCSTA2
REGISTER FILE SUMMARY (CONTINUED)
Bit 7 -- Bit 6 LATA6(1) Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Details on page:
Read PORTA Data Latch, Write PORTA Data Latch(1)
-xxx xxxx 35, 103 xxxx xxxx 36, 127 xxxx xxxx 36, 124 ---x xxxx 36, 121 xxxx xxxx 36, 119 xxxx xxxx 36, 114 xxxx xxxx 36, 111 xxxx xxxx 36, 109 xxxx xxxx 36, 106
Read PORTJ pins, Write PORTJ Data Latch Read PORTH pins, Write PORTH Data Latch -- -- -- Read PORTG pins, Write PORTG Data Latch Read PORTF pins, Write PORTF Data Latch Read PORTE pins, Write PORTE Data Latch Read PORTD pins, Write PORTD Data Latch Read PORTC pins, Write PORTC Data Latch Read PORTB pins, Write PORTB Data Latch -- RA6
(1)
Read PORTA pins, Write PORTA Data Latch
(1)
-x0x 0000 36, 103 0000 0000 36, 148 1111 1111 36, 148
Timer4 Register Timer4 Period Register -- T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 Capture/Compare/PWM Register 4 High Byte Capture/Compare/PWM Register 4 Low Byte -- -- DC4B1 DC4B0 CCP4M3 CCP4M2 CCP4M1 Capture/Compare/PWM Register 5 High Byte Capture/Compare/PWM Register 5 Low Byte -- -- DC5B1 DC5B0 CCP5M3 CCP5M2 CCP5M1 USART2 Baud Rate Generator USART2 Receive Register USART2 Transmit Register CSRC SPEN TX9 RX9 TXEN SREN SYNC CREN -- ADDEN BRGH FERR TRMT OERR TX9D RX9D
T4CKPS0 -000 0000 36, 147 xxxx xxxx 36, 153 xxxx xxxx 36, 153 CCP4M0 0000 0000 36, 149 xxxx xxxx 36, 153 xxxx xxxx 36, 153 CCP5M0 0000 0000 36, 149 0000 0000 36, 205 0000 0000 36, 205 0000 0000 36, 205 0000 -010 36, 198 0000 000x 36, 199
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes. 2: Bit 21 of the TBLPTRU allows access to the device configuration bits. 3: These registers are unused on PIC18F6X20 devices; always maintain these clear.
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4.10 Access Bank 4.11 Bank Select Register (BSR)
The Access Bank is an architectural enhancement, which is very useful for C compiler code optimization. The techniques used by the C compiler may also be useful for programs written in assembly. This data memory region can be used for: * * * * * Intermediate computational values Local variables of subroutines Faster context saving/switching of variables Common variables Faster evaluation/control of SFRs (no banking) The need for a large general purpose memory space dictates a RAM banking scheme. The data memory is partitioned into sixteen banks. When using direct addressing, the BSR should be configured for the desired bank. BSR<3:0> holds the upper 4 bits of the 12-bit RAM address. The BSR<7:4> bits will always read `0's, and writes will have no effect. A MOVLB instruction has been provided in the instruction set to assist in selecting banks. If the currently selected bank is not implemented, any read will return all '0's and all writes are ignored. The STATUS register bits will be set/cleared as appropriate for the instruction performed. Each Bank extends up to FFh (256 bytes). All data memory is implemented as static RAM. A MOVFF instruction ignores the BSR, since the 12-bit addresses are embedded into the instruction word. Section 4.12 provides a description of indirect addressing, which allows linear addressing of the entire RAM space.
The Access Bank is comprised of the upper 160 bytes in Bank 15 (SFRs) and the lower 96 bytes in Bank 0. These two sections will be referred to as Access RAM High and Access RAM Low, respectively. Figure 4-7 indicates the Access RAM areas. A bit in the instruction word specifies if the operation is to occur in the bank specified by the BSR register or in the Access Bank. This bit is denoted by the `a' bit (for access bit). When forced in the Access Bank (a = 0), the last address in Access RAM Low is followed by the first address in Access RAM High. Access RAM High maps the Special Function registers, so that these registers can be accessed without any software overhead. This is useful for testing status flags and modifying control bits.
FIGURE 4-8:
DIRECT ADDRESSING
Direct Addressing
BSR<3:0> 7 From Opcode(3) 0
Bank Select(2)
Location Select(3) 00h 000h 01h 100h 0Eh E00h 0Fh F00h
Data Memory(1)
0FFh
1FFh
EFFh
FFFh
Bank 0
Note 1: For register file map detail, see Table 4-2.
Bank 1
Bank 14
Bank 15
2: The access bit of the instruction can be used to force an override of the selected bank (BSR<3:0>) to the registers of the Access Bank. 3: The MOVFF instruction embeds the entire 12-bit address in the instruction.
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4.12 Indirect Addressing, INDF and FSR Registers
the data from the address pointed to by FSR1H:FSR1L. INDFn can be used in code anywhere an operand can be used. If INDF0, INDF1, or INDF2 are read indirectly via an FSR, all '0's are read (zero bit is set). Similarly, if INDF0, INDF1, or INDF2 are written to indirectly, the operation will be equivalent to a NOP instruction and the STATUS bits are not affected.
Indirect addressing is a mode of addressing data memory, where the data memory address in the instruction is not fixed. An FSR register is used as a pointer to the data memory location that is to be read or written. Since this pointer is in RAM, the contents can be modified by the program. This can be useful for data tables in the data memory and for software stacks. Figure 4-9 shows the operation of indirect addressing. This shows the moving of the value to the data memory address, specified by the value of the FSR register. Indirect addressing is possible by using one of the INDF registers. Any instruction using the INDF register actually accesses the register pointed to by the File Select Register, FSR. Reading the INDF register itself, indirectly (FSR = 0), will read 00h. Writing to the INDF register indirectly, results in a no operation. The FSR register contains a 12-bit address, which is shown in Figure 4-10. The INDFn register is not a physical register. Addressing INDFn actually addresses the register whose address is contained in the FSRn register (FSRn is a pointer). This is indirect addressing. Example 4-4 shows a simple use of indirect addressing to clear the RAM in Bank 1 (locations 100h-1FFh) in a minimum number of instructions.
4.12.1
INDIRECT ADDRESSING OPERATION
Each FSR register has an INDF register associated with it, plus four additional register addresses. Performing an operation on one of these five registers determines how the FSR will be modified during indirect addressing. When data access is done to one of the five INDFn locations, the address selected will configure the FSRn register to: * Do nothing to FSRn after an indirect access (no change) - INDFn. * Auto-decrement FSRn after an indirect access (post-decrement) - POSTDECn. * Auto-increment FSRn after an indirect access (post-increment) - POSTINCn. * Auto-increment FSRn before an indirect access (pre-increment) - PREINCn. * Use the value in the WREG register as an offset to FSRn. Do not modify the value of the WREG or the FSRn register after an indirect access (no change) - PLUSWn. When using the auto-increment or auto-decrement features, the effect on the FSR is not reflected in the STATUS register. For example, if the indirect address causes the FSR to equal '0', the Z bit will not be set. Incrementing or decrementing an FSR affects all 12 bits. That is, when FSRnL overflows from an increment, FSRnH will be incremented automatically. Adding these features allows the FSRn to be used as a stack pointer, in addition to its uses for table operations in data memory. Each FSR has an address associated with it that performs an indexed indirect access. When a data access to this INDFn location (PLUSWn) occurs, the FSRn is configured to add the signed value in the WREG register and the value in FSR to form the address before an indirect access. The FSR value is not changed. If an FSR register contains a value that points to one of the INDFn, an indirect read will read 00h (zero bit is set), while an indirect write will be equivalent to a NOP (STATUS bits are not affected). If an indirect addressing operation is done where the target address is an FSRnH or FSRnL register, the write operation will dominate over the pre- or post-increment/decrement functions.
EXAMPLE 4-4:
HOW TO CLEAR RAM (BANK 1) USING INDIRECT ADDRESSING
FSR0 ,0x100 ; POSTINC0 ; Clear INDF ; register and ; inc pointer BTFSS FSR0H, 1 ; All done with ; Bank 1? GOTO NEXT ; NO, clear next CONTINUE ; YES, continue NEXT
LFSR CLRF
There are three indirect addressing registers. To address the entire data memory space (4096 bytes), these registers are 12-bits wide. To store the 12 bits of addressing information, two 8-bit registers are required. These indirect addressing registers are: 1. 2. 3. FSR0: composed of FSR0H:FSR0L FSR1: composed of FSR1H:FSR1L FSR2: composed of FSR2H:FSR2L
In addition, there are registers INDF0, INDF1 and INDF2, which are not physically implemented. Reading or writing to these registers activates indirect addressing, with the value in the corresponding FSR register being the address of the data. If an instruction writes a value to INDF0, the value will be written to the address pointed to by FSR0H:FSR0L. A read from INDF1 reads
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FIGURE 4-9: INDIRECT ADDRESSING OPERATION
RAM Instruction Executed Opcode Address FFFh 12 File Address = Access of an Indirect Addressing Register 0h
BSR<3:0> Instruction Fetched Opcode 4
12 8 File
12
FSR
FIGURE 4-10:
INDIRECT ADDRESSING
Indirect Addressing
11 FSR Register 0
Location Select
0000h
Data Memory(1)
0FFFh Note 1: For register file map detail, see Table 4-2.
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4.13 STATUS Register
The STATUS register, shown in Register 4-3, contains the arithmetic status of the ALU. The STATUS register can be the destination for any instruction, as with any other register. If the STATUS register is the destination for an instruction that affects the Z, DC, C, OV, or N bits, then the write to these five bits is disabled. These bits are set or cleared according to the device logic. Therefore, the result of an instruction with the STATUS register as destination may be different than intended. For example, CLRF STATUS will clear the upper three bits and set the Z bit. This leaves the STATUS register as 000u u1uu (where u = unchanged). It is recommended, therefore, that only BCF, BSF, SWAPF, MOVFF and MOVWF instructions are used to alter the STATUS register, because these instructions do not affect the Z, C, DC, OV, or N bits from the STATUS register. For other instructions not affecting any status bits, see Table 24-2. Note: The C and DC bits operate as a borrow and digit borrow bit respectively, in subtraction.
REGISTER 4-3:
STATUS REGISTER
U-0 -- bit 7 U-0 -- U-0 -- R/W-x N R/W-x OV R/W-x Z R/W-x DC R/W-x C bit 0
bit 7-5 bit 4
Unimplemented: Read as '0' N: Negative bit This bit is used for signed arithmetic (2's complement). It indicates whether the result was negative (ALU MSB = 1). 1 = Result was negative 0 = Result was positive OV: Overflow bit This bit is used for signed arithmetic (2's complement). It indicates an overflow of the 7-bit magnitude, which causes the sign bit (bit 7) to change state. 1 = Overflow occurred for signed arithmetic (in this arithmetic operation) 0 = No overflow occurred Z: Zero bit 1 = The result of an arithmetic or logic operation is zero 0 = The result of an arithmetic or logic operation is not zero DC: Digit carry/borrow bit For ADDWF, ADDLW, SUBLW, and SUBWF instructions 1 = A carry-out from the 4th low order bit of the result occurred 0 = No carry-out from the 4th low order bit of the result Note: For borrow, the polarity is reversed. A subtraction is executed by adding the two's complement of the second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either bit 4 or bit 3 of the source register.
bit 3
bit 2
bit 1
bit 0
C: Carry/borrow bit For ADDWF, ADDLW, SUBLW, and SUBWF instructions 1 = A carry-out from the Most Significant bit of the result occurred 0 = No carry-out from the Most Significant bit of the result occurred Note: For borrow, the polarity is reversed. A subtraction is executed by adding the two's complement of the second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low order bit of the source register.
Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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4.14 RCON Register
The RESET Control (RCON) register contains flag bits that allow differentiation between the sources of a device RESET. These flags include the TO, PD, POR, BOR and RI bits. This register is readable and writable. Note 1: If the BOREN configuration bit is set (Brown-out Reset enabled), the BOR bit is `1' on a Power-on Reset. After a Brown-out Reset has occurred, the BOR bit will be cleared, and must be set by firmware to indicate the occurrence of the next Brown-out Reset. 2: It is recommended that the POR bit be set after a Power-on Reset has been detected, so that subsequent Power-on Resets may be detected.
REGISTER 4-4:
RCON REGISTER
R/W-0 IPEN bit 7 U-0 -- U-0 -- R/W-1 RI R/W-1 TO R/W-1 PD R/W-0 POR R/W-0 BOR bit 0
bit 7
IPEN: Interrupt Priority Enable bit 1 = Enable priority levels on interrupts 0 = Disable priority levels on interrupts (PIC16CXXX Compatibility mode) Unimplemented: Read as '0' RI: RESET Instruction Flag bit 1 = The RESET instruction was not executed 0 = The RESET instruction was executed causing a device RESET (must be set in software after a Brown-out Reset occurs) TO: Watchdog Time-out Flag bit 1 = After power-up, CLRWDT instruction, or SLEEP instruction 0 = A WDT time-out occurred PD: Power-down Detection Flag bit 1 = After power-up or by the CLRWDT instruction 0 = By execution of the SLEEP instruction POR: Power-on Reset Status bit 1 = A Power-on Reset has not occurred 0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs) BOR: Brown-out Reset Status bit 1 = A Brown-out Reset has not occurred 0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs) Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6-5 bit 4
bit 3
bit 2
bit 1
bit 0
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5.0 FLASH PROGRAM MEMORY
The FLASH Program Memory is readable, writable, and erasable, during normal operation over the entire VDD range. A read from program memory is executed on one byte at a time. A write to program memory is executed on blocks of 8 bytes at a time. Program memory is erased in blocks of 64 bytes at a time. A bulk erase operation may not be issued from user code. Writing or erasing program memory will cease instruction fetches until the operation is complete. The program memory cannot be accessed during the write or erase, therefore, code cannot execute. An internal programming timer terminates program memory writes and erases. A value written to program memory does not need to be a valid instruction. Executing a program memory location that forms an invalid instruction results in a NOP. The program memory space is 16-bits wide, while the data RAM space is 8-bits wide. Table Reads and Table Writes move data between these two memory spaces through an 8-bit register (TABLAT). Table Read operations retrieve data from program memory and place it into the data RAM space. Figure 5-1 shows the operation of a Table Read with program memory and data RAM. Table Write operations store data from the data memory space into holding registers in program memory. The procedure to write the contents of the holding registers into program memory is detailed in Section 5.5, '"Writing to FLASH Program Memory". Figure 5-2 shows the operation of a Table Write with program memory and data RAM. Table operations work with byte entities. A table block containing data, rather than program instructions, is not required to be word aligned. Therefore, a table block can start and end at any byte address. If a Table Write is being used to write executable code into program memory, program instructions will need to be word aligned.
5.1
Table Reads and Table Writes
In order to read and write program memory, there are two operations that allow the processor to move bytes between the program memory space and the data RAM: * Table Read (TBLRD) * Table Write (TBLWT)
FIGURE 5-1:
TABLE READ OPERATION
Instruction: TBLRD*
Table Pointer(1) TBLPTRU TBLPTRH TBLPTRL
Program Memory Table Latch (8-bit) TABLAT
Program Memory (TBLPTR)
Note 1: Table Pointer points to a byte in program memory.
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FIGURE 5-2: TABLE WRITE OPERATION
Instruction: TBLWT* Program Memory Holding Registers Table Pointer(1) TBLPTRU TBLPTRH TBLPTRL Table Latch (8-bit) TABLAT
Program Memory (TBLPTR)
Note 1: Table Pointer actually points to one of eight holding registers, the address of which is determined by TBLPTRL<2:0>. The process for physically writing data to the Program Memory Array is discussed in Section 5.5.
5.2
Control Registers
Several control registers are used in conjunction with the TBLRD and TBLWT instructions. These include the: * * * * EECON1 register EECON2 register TABLAT register TBLPTR registers
The FREE bit, when set, will allow a program memory erase operation. When the FREE bit is set, the erase operation is initiated on the next WR command. When FREE is clear, only writes are enabled. The WREN bit, when set, will allow a write operation. On power-up, the WREN bit is clear. The WRERR bit is set when a write operation is interrupted by a MCLR Reset, or a WDT Time-out Reset during normal operation. In these situations, the user can check the WRERR bit and rewrite the location. It is necessary to reload the data and address registers (EEDATA and EEADR), due to RESET values of zero. The WR control bit, WR, initiates write operations. The bit cannot be cleared, only set, in software; it is cleared in hardware at the completion of the write operation. The inability to clear the WR bit in software prevents the accidental or premature termination of a write operation. Note: Interrupt flag bit, EEIF in the PIR2 register, is set when the write is complete. It must be cleared in software.
5.2.1
EECON1 AND EECON2 REGISTERS
EECON1 is the control register for memory accesses. EECON2 is not a physical register. Reading EECON2 will read all '0's. The EECON2 register is used exclusively in the memory write and erase sequences. Control bit EEPGD determines if the access will be a program or data EEPROM memory access. When clear, any subsequent operations will operate on the data EEPROM memory. When set, any subsequent operations will operate on the program memory. Control bit CFGS determines if the access will be to the configuration/calibration registers, or to program memory/data EEPROM memory. When set, subsequent operations will operate on configuration registers, regardless of EEPGD (see "Special Features of the CPU", Section 23.0). When clear, memory selection access is determined by EEPGD.
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REGISTER 5-1: EECON1 REGISTER (ADDRESS FA6h)
R/W-x EEPGD bit 7 bit 7 EEPGD: FLASH Program or Data EEPROM Memory Select bit 1 = Access FLASH Program memory 0 = Access Data EEPROM memory CFGS: FLASH Program/Data EEPROM or Configuration Select bit 1 = Access Configuration registers 0 = Access FLASH Program or Data EEPROM memory Unimplemented: Read as '0' FREE: FLASH Row Erase Enable bit 1 = Erase the program memory row addressed by TBLPTR on the next WR command (cleared by completion of erase operation) 0 = Perform write only WRERR: FLASH Program/Data EEPROM Error Flag bit 1 = A write operation is prematurely terminated (any RESET during self-timed programming in normal operation) 0 = The write operation completed Note: bit 2 When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows tracing of the error condition. R/W-x CFGS U-0 -- R/W-0 FREE R/W-x WRERR R/W-0 WREN R/S-0 WR R/S-0 RD bit 0
bit 6
bit 5 bit 4
bit 3
WREN: FLASH Program/Data EEPROM Write Enable bit 1 = Allows write cycles to FLASH Program/Data EEPROM 0 = Inhibits write cycles to FLASH Program/Data EEPROM WR: Write Control bit 1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write cycle. (The operation is self-timed and the bit is cleared by hardware once write is complete. The WR bit can only be set (not cleared) in software.) 0 = Write cycle to the EEPROM is complete RD: Read Control bit 1 = Initiates an EEPROM read (Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared) in software. RD bit cannot be set when EEPGD = 1.) 0 = Does not initiate an EEPROM read Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 1
bit 0
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5.2.2 TABLAT - TABLE LATCH REGISTER 5.2.4 TABLE POINTER BOUNDARIES
The Table Latch (TABLAT) is an 8-bit register mapped into the SFR space. The Table Latch is used to hold 8-bit data during data transfers between program memory and data RAM. TBLPTR is used in reads, writes, and erases of the FLASH program memory. When a TBLRD is executed, all 22 bits of the Table Pointer determine which byte is read from program memory into TABLAT. When a TBLWT is executed, the three LSbs of the Table Pointer (TBLPTR<2:0>) determine which of the eight program memory holding registers is written to. When the timed write to program memory (long write) begins, the 19 MSbs of the Table Pointer, TBLPTR (TBLPTR<21:3>), will determine which program memory block of 8 bytes is written to. For more detail, see Section 5.5 ("Writing to FLASH Program Memory"). When an erase of program memory is executed, the 16 MSbs of the Table Pointer (TBLPTR<21:6>) point to the 64-byte block that will be erased. The Least Significant bits (TBLPTR<5:0>) are ignored. Figure 5-3 describes the relevant boundaries of TBLPTR based on FLASH program memory operations.
5.2.3
TBLPTR - TABLE POINTER REGISTER
The Table Pointer (TBLPTR) addresses a byte within the program memory. The TBLPTR is comprised of three SFR registers: Table Pointer Upper Byte, Table Pointer High Byte and Table Pointer Low Byte (TBLPTRU:TBLPTRH:TBLPTRL). These three registers join to form a 22-bit wide pointer. The low order 21 bits allow the device to address up to 2 Mbytes of program memory space. The 22nd bit allows access to the Device ID, the User ID and the Configuration bits. The table pointer, TBLPTR, is used by the TBLRD and TBLWT instructions. These instructions can update the TBLPTR in one of four ways, based on the table operation. These operations are shown in Table 5-1. These operations on the TBLPTR only affect the low order 21 bits.
TABLE 5-1:
Example TBLRD* TBLWT* TBLRD*+ TBLWT*+ TBLRD*TBLWT*TBLRD+* TBLWT+*
TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
Operation on Table Pointer TBLPTR is not modified TBLPTR is incremented after the read/write TBLPTR is decremented after the read/write TBLPTR is incremented before the read/write
FIGURE 5-3:
21
TABLE POINTER BOUNDARIES BASED ON OPERATION
TBLPTRU 16 15 TBLPTRH 8 7 TBLPTRL 0
ERASE - TBLPTR<20:6> WRITE - TBLPTR<21:3> READ - TBLPTR<21:0>
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5.3 Reading the FLASH Program Memory
TBLPTR points to a byte address in program space. Executing TBLRD places the byte pointed to into TABLAT. In addition, TBLPTR can be modified automatically for the next Table Read operation. The internal program memory is typically organized by words. The Least Significant bit of the address selects between the high and low bytes of the word. Figure 5-4 shows the interface between the internal program memory and the TABLAT.
The TBLRD instruction is used to retrieve data from program memory and places it into data RAM. Table Reads from program memory are performed one byte at a time.
FIGURE 5-4:
READS FROM FLASH PROGRAM MEMORY
Program Memory
(Even Byte Address)
(Odd Byte Address)
TBLPTR = xxxxx1
TBLPTR = xxxxx0
Instruction Register (IR)
FETCH
TBLRD
TABLAT Read Register
EXAMPLE 5-1:
MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF READ_WORD
READING A FLASH PROGRAM MEMORY WORD
CODE_ADDR_UPPER TBLPTRU CODE_ADDR_HIGH TBLPTRH CODE_ADDR_LOW TBLPTRL ; Load TBLPTR with the base ; address of the word
TBLRD*+ MOVF MOVWF TBLRD*+ MOVFW MOVWF
TABLAT, W WORD_EVEN TABLAT, W WORD_ODD
; read into TABLAT and increment ; get data ; read into TABLAT and increment ; get data
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5.4 Erasing FLASH Program Memory
5.4.1
The minimum erase block is 32 words or 64 bytes. Only through the use of an external programmer, or through ICSP control, can larger blocks of program memory be bulk erased. Word erase in the FLASH array is not supported. When initiating an erase sequence from the microcontroller itself, a block of 64 bytes of program memory is erased. The Most Significant 16 bits of the TBLPTR<21:6> point to the block being erased. TBLPTR<5:0> are ignored. The EECON1 register commands the erase operation. The EEPGD bit must be set to point to the FLASH program memory. The WREN bit must be set to enable write operations. The FREE bit is set to select an erase operation. For protection, the write initiate sequence for EECON2 must be used. A long write is necessary for erasing the internal FLASH. Instruction execution is halted while in a long write cycle. The long write will be terminated by the internal programming timer.
FLASH PROGRAM MEMORY ERASE SEQUENCE
The sequence of events for erasing a block of internal program memory location is: 1. 2. Load table pointer with address of row being erased. Set the EECON1 register for the erase operation: * set EEPGD bit to point to program memory; * clear the CFGS bit to access program memory; * set WREN bit to enable writes; * set FREE bit to enable the erase. Disable interrupts. Write 55h to EECON2. Write AAh to EECON2. Set the WR bit. This will begin the row erase cycle. The CPU will stall for duration of the erase (about 2 ms using internal timer). Execute a NOP. Re-enable interrupts.
3. 4. 5. 6. 7. 8. 9.
EXAMPLE 5-2:
ERASING A FLASH PROGRAM MEMORY ROW
MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF CODE_ADDR_UPPER TBLPTRU CODE_ADDR_HIGH TBLPTRH CODE_ADDR_LOW TBLPTRL EECON1,EEPGD EECON1,CFGS EECON1,WREN EECON1,FREE INTCON,GIE 55h EECON2 AAh EECON2 EECON1,WR INTCON,GIE ; load TBLPTR with the base ; address of the memory block
ERASE_ROW BSF BCF BSF BSF BCF MOVLW MOVWF MOVLW MOVWF BSF NOP BSF ; ; ; ; ; point to FLASH program memory access FLASH program memory enable write to memory enable Row Erase operation disable interrupts
Required Sequence
; write 55H ; write AAH ; start erase (CPU stall) ; re-enable interrupts
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5.5 Writing to FLASH Program Memory
the holding registers are written. At the end of updating 8 registers, the EECON1 register must be written to, to start the programming operation with a long write. The long write is necessary for programming the internal FLASH. Instruction execution is halted while in a long write cycle. The long write will be terminated by the internal programming timer. The EEPROM on-chip timer controls the write time. The write/erase voltages are generated by an on-chip charge pump, rated to operate over the voltage range of the device for byte or word operations.
The minimum programming block is 4 words or 8 bytes. Word or byte programming is not supported. Table Writes are used internally to load the holding registers needed to program the FLASH memory. There are 8 holding registers used by the Table Writes for programming. Since the Table Latch (TABLAT) is only a single byte, the TBLWT instruction has to be executed 8 times for each programming operation. All of the Table Write operations will essentially be short writes, because only
FIGURE 5-5:
TABLE WRITES TO FLASH PROGRAM MEMORY
TABLAT Write Register
8
TBLPTR = xxxxx0 TBLPTR = xxxxx1
8
TBLPTR = xxxxx2
8
TBLPTR = xxxxx7
8
Holding Register
Holding Register
Holding Register
Holding Register
Program Memory
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5.5.1 FLASH PROGRAM MEMORY WRITE SEQUENCE
The sequence of events for programming an internal program memory location should be: 1. 2. 3. 4. 5. 6. 7. Read 64 bytes into RAM. Update data values in RAM as necessary. Load Table Pointer with address being erased. Do the row erase procedure. Load Table Pointer with address of first byte being written. Write the first 8 bytes into the holding registers with auto-increment. Set the EECON1 register for the write operation: * set EEPGD bit to point to program memory; * clear the CFGS bit to access program memory; * set WREN to enable byte writes. Disable interrupts. Write 55h to EECON2. Write AAh to EECON2. Set the WR bit. This will begin the write cycle. The CPU will stall for duration of the write (about 2 ms using internal timer). Execute a NOP. Re-enable interrupts. Repeat steps 6-14 seven times, to write 64 bytes. Verify the memory (Table Read). This procedure will require about 18 ms to update one row of 64 bytes of memory. An example of the required code is given in Example 5-3. Note: Before setting the WR bit, the Table Pointer address needs to be within the intended address range of the eight bytes in the holding register.
8. 9. 10. 11. 12. 13. 14. 15. 16.
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EXAMPLE 5-3: WRITING TO FLASH PROGRAM MEMORY
MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF READ_BLOCK TBLRD*+ MOVF MOVWF DECFSZ BRA MODIFY_WORD MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF ERASE_BLOCK MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF BSF BCF BSF BSF BCF MOVLW Required MOVWF Sequence MOVLW MOVWF BSF NOP BSF TBLRD*WRITE_BUFFER_BACK MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF PROGRAM_LOOP MOVLW MOVWF WRITE_WORD_TO_HREGS MOVFW MOVWF TBLWT+* CODE_ADDR_UPPER TBLPTRU CODE_ADDR_HIGH TBLPTRH CODE_ADDR_LOW TBLPTRL EECON1,EEPGD EECON1,CFGS EECON1,WREN EECON1,FREE INTCON,GIE 55h EECON2 AAh EECON2 EECON1,WR INTCON,GIE ; load TBLPTR with the base ; address of the memory block DATA_ADDR_HIGH FSR0H DATA_ADDR_LOW FSR0L NEW_DATA_LOW POSTINC0 NEW_DATA_HIGH INDF0 ; point to buffer TABLAT, W POSTINC0 COUNTER READ_BLOCK ; ; ; ; ; read into TABLAT, and inc get data store data done? repeat D'64 COUNTER BUFFER_ADDR_HIGH FSR0H BUFFER_ADDR_LOW FSR0L CODE_ADDR_UPPER TBLPTRU CODE_ADDR_HIGH TBLPTRH CODE_ADDR_LOW TBLPTRL ; number of bytes in erase block ; point to buffer
; Load TBLPTR with the base ; address of the memory block
; update buffer word
; ; ; ; ;
point to FLASH program memory access FLASH program memory enable write to memory enable Row Erase operation disable interrupts
; write 55H ; write AAH ; start erase (CPU stall) ; re-enable interrupts ; dummy read decrement ; number of write buffer groups of 8 bytes ; point to buffer
8 COUNTER_HI BUFFER_ADDR_HIGH FSR0H BUFFER_ADDR_LOW FSR0L 8 COUNTER POSTINC0, W TABLAT
; number of bytes in holding register
DECFSZ COUNTER BRA WRITE_WORD_TO_HREGS
; ; ; ; ;
get low byte of buffer data present data to table latch write data, perform a short write to internal TBLWT holding register. loop until buffers are full
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EXAMPLE 5-3:
PROGRAM_MEMORY BSF EECON1,EEPGD BCF EECON1,CFGS BSF EECON1,WREN BCF INTCON,GIE MOVLW 55h MOVWF EECON2 MOVLW AAh MOVWF EECON2 BSF EECON1,WR NOP BSF INTCON,GIE DECFSZ COUNTER_HI BRA PROGRAM_LOOP BCF EECON1,WREN ; ; ; ; point to FLASH program memory access FLASH program memory enable write to memory disable interrupts
WRITING TO FLASH PROGRAM MEMORY (CONTINUED)
Required Sequence
; write 55H ; write AAH ; start program (CPU stall) ; re-enable interrupts ; loop until done ; disable write to memory
5.5.2
WRITE VERIFY
Depending on the application, good programming practice may dictate that the value written to the memory should be verified against the original value. This should be used in applications where excessive writes can stress bits near the specification limit.
Time-out Reset during normal operation. In these situations, users can check the WRERR bit and rewrite the location.
5.5.4
PROTECTION AGAINST SPURIOUS WRITES
5.5.3
UNEXPECTED TERMINATION OF WRITE OPERATION
If a write is terminated by an unplanned event, such as loss of power or an unexpected RESET, the memory location just programmed should be verified and reprogrammed if needed.The WRERR bit is set when a write operation is interrupted by a MCLR Reset, or a WDT
To protect against spurious writes to FLASH program memory, the write initiate sequence must also be followed. See "Special Features of the CPU" (Section 23.0) for more detail.
5.6
FLASH Program Operation During Code Protection
See "Special Features of the CPU" (Section 23.0) for details on code protection of FLASH program memory.
TABLE 5-2:
Name
REGISTERS ASSOCIATED WITH PROGRAM FLASH MEMORY
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on: POR, BOR --00 0000 0000 0000 0000 0000 0000 0000 INTE FREE EEIP EEIF EEIE RBIE WRERR BCLIP BCLIF BCLIE TMR0IF WREN LVDIP LVDIF LVDIE INTF WR TMR3IP TMR3IF TMR3IE RBIF RD CCP2IP CCP2IF CCP2IE 0000 0000 -- xx-0 x000 ---1 1111 ---0 0000 ---0 0000 Value on all other RESETS --00 0000 0000 0000 0000 0000 0000 0000 0000 0000 -- uu-0 u000 ---1 1111 ---0 0000 ---0 0000
TBLPTRU TBPLTRH TBLPTRL TABLAT INTCON EECON2 EECON1 IPR2 PIR2 PIE2 Legend:
--
--
bit21
Program Memory Table Pointer Upper Byte (TBLPTR<20:16>)
Program Memory Table Pointer High Byte (TBLPTR<15:8>) Program Memory Table Pointer High Byte (TBLPTR<7:0>) Program Memory Table Latch GIE/GIEH PEIE/GIEL TMR0IE EEPGD -- -- -- CFGS CMIP CMIF CMIE -- -- -- -- EEPROM Control Register2 (not a physical register)
x = unknown, u = unchanged, r = reserved, - = unimplemented, read as '0'. Shaded cells are not used during FLASH/EEPROM access.
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6.0
Note:
EXTERNAL MEMORY INTERFACE
The External Memory Interface is not implemented on PIC18F6X20 (64-pin) devices.
6.1
Program Memory Modes and the External Memory Interface
The External Memory Interface is a feature of the PIC18F8X20 devices that allows the controller to access external memory devices (such as FLASH, EPROM, SRAM, etc.) as program or data memory. The physical implementation of the interface uses 27 pins. These pins are reserved for external address/data bus functions; they are multiplexed with I/O port pins on four ports. Three I/O ports are multiplexed with the address/data bus, while the fourth port is multiplexed with the bus control signals. The I/O port functions are enabled when the EBDIS bit in the MEMCON register is set (see Register 6-1). A list of the multiplexed pins and their functions is provided in Table 6-1. As implemented in the PIC18F8X20 devices, the interface operates in a similar manner to the external memory interface introduced on PIC18C601/801 microcontrollers. The most notable difference is that the interface on PIC18F8X20 devices only operates in 16-bit modes. The 8-bit mode is not supported. For a more complete discussion of the Operating modes that use the external memory interface, refer to Section 4.1.1 ("PIC18F8X20 Program Memory Modes").
As previously noted, PIC18F8X20 controllers are capable of operating in any one of four Program Memory modes, using combinations of on-chip and external program memory. The functions of the multiplexed port pins depend on the Program Memory mode selected, as well as the setting of the EBDIS bit. In Microprocessor Mode, the external bus is always active, and the port pins have only the external bus function. In Microcontroller Mode, the bus is not active and the pins have their port functions only. Writes to the MEMCOM register are not permitted. In Microprocessor with Boot Block or Extended Microcontroller Mode, the external program memory bus shares I/O port functions on the pins. When the device is fetching or doing Table Read/Table Write operations on the external program memory space, the pins will have the external bus function. If the device is fetching and accessing internal program memory locations only, the EBDIS control bit will change the pins from external memory to I/O port functions. When EBDIS = 0, the pins function as the external bus. When EBDIS = 1, the pins function as I/O ports.
REGISTER 6-1:
MEMCON REGISTER
R/W-0 EBDIS bit7 U-0 -- R/W-0 WAIT1 R/W-0 WAIT0 U-0 -- U-0 -- R/W-0 WM1 R/W-0 WM0 bit0
bit 7
EBDIS: External Bus Disable bit 1 = External system bus disabled, all external bus drivers are mapped as I/O ports 0 = External system bus enabled, and I/O ports are disabled Unimplemented: Read as '0' WAIT<1:0>: Table Reads and Writes Bus Cycle Wait Count bits 11 = Table reads and writes will wait 0 TCY 10 = Table reads and writes will wait 1 TCY 01 = Table reads and writes will wait 2 TCY 00 = Table reads and writes will wait 3 TCY Unimplemented: Read as '0' WM<1:0>: TBLWRT Operation with 16-bit Bus bits 1x = Word Write mode: TABLAT<0> and TABLAT<1> word output, WRH active when TABLAT<1> written 01 = Byte Select mode: TABLAT data copied on both MS and LS Byte, WRH and (UB or LB) will activate 00 = Byte Write mode: TABLAT data copied on both MS and LS Byte, WRH or WRL will activate Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6 bit 5-4
bit 3-2 bit 1-0
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If the device fetches or accesses external memory while EBDIS = 1, the pins will switch to external bus. If the EBDIS bit is set by a program executing from external memory, the action of setting the bit will be delayed until the program branches into the internal memory. At that time, the pins will change from external bus to I/O ports. When the device is executing out of internal memory (EBDIS = 0) in Microprocessor with Boot Block mode, or Extended Microcontroller mode, the control signals will NOT be active. They will go to a state where the AD<15:0> and A<19:16> are tri-state; the CE, OE, WRH, WRL, UB and LB signals are `1'; and ALE and BA0 are `0'.
TABLE 6-1:
Name RD0/AD0 RD1/AD1 RD2/AD2 RD3/AD3 RD4/AD4 RD5/AD5 RD6/AD6 RD7/AD7 RE0/AD8 RE1/AD9 RE2/AD10 RE3/AD11 RE4/AD12 RE5/AD13 RE6/AD14 RE7/AD15 RH0/A16 RH1/A17 RH2/A18 RH3/A19 RJ0/ALE RJ1/OE RJ2/WRL RJ3/WRH RJ4/BA0 RJ5/CE RJ6/LB RJ7/UB
PIC18F8X20 EXTERNAL BUS - I/O PORT FUNCTIONS
Port PORTD PORTD PORTD PORTD PORTD PORTD PORTD PORTD PORTE PORTE PORTE PORTE PORTE PORTE PORTE PORTE PORTH PORTH PORTH PORTH PORTJ PORTJ PORTJ PORTJ PORTJ PORTJ PORTJ PORTJ Bit Function
bit0 Input/Output or System Bus Address bit 0 or Data bit 0. bit1 Input/Output or System Bus Address bit 1 or Data bit 1. bit2 Input/Output or System Bus Address bit 2 or Data bit 2. bit3 Input/Output or System Bus Address bit 3 or Data bit 3. bit4 Input/Output or System Bus Address bit 4 or Data bit 4. bit5 Input/Output or System Bus Address bit 5 or Data bit 5. bit6 Input/Output or System Bus Address bit 6 or Data bit 6. bit7 Input/Output or System Bus Address bit 7 or Data bit 7. bit0 Input/Output or System Bus Address bit 8 or Data bit 8. bit1 Input/Output or System Bus Address bit 9 or Data bit 9. bit2 Input/Output or System Bus Address bit 10 or Data bit 10. bit3 Input/Output or System Bus Address bit 11 or Data bit 11. bit4 Input/Output or System Bus Address bit 12 or Data bit 12. bit5 Input/Output or System Bus Address bit 13 or Data bit 13. bit6 Input/Output or System Bus Address bit 14 or Data bit 14. bit7 Input/Output or System Bus Address bit 15 or Data bit 15. bit0 Input/Output or System Bus Address bit 16. bit1 Input/Output or System Bus Address bit 17. bit2 Input/Output or System Bus Address bit 18. bit3 Input/Output or System Bus Address bit 19. bit0 Input/Output or System Bus Address Latch Enable (ALE) Control pin. bit1 Input/Output or System Bus Output Enable (OE) Control pin. bit2 Input/Output or System Bus Write Low (WRL) Control pin. bit3 Input/Output or System Bus Write High (WRH) Control pin. bit4 Input/Output or System Bus Byte Address bit 0. bit5 Input/Output or System Bus Chip Enable (CE) Control pin. bit6 Input/Output or System Bus Lower Byte Enable (LB) Control pin. bit7 Input/Output or System Bus Upper Byte Enable (UB) Control pin.
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6.2 16-bit Mode
The External Memory Interface implemented in PIC18F8X20 devices operates only in 16-bit mode. The mode selection is not software configurable, but is programmed via the configuration bits. The WM<1:0> bits in the MEMCON register determine three types of connections in 16-bit mode. They are referred to as: * 16-bit Byte Write * 16-bit Word Write * 16-bit Byte Select These three different configurations allow the designer maximum flexibility in using 8-bit and 16-bit memory devices. For all 16-bit modes, the Address Latch Enable (ALE) pin indicates that the address bits A<15:0> are available on the External Memory Interface bus. Following the address latch, the output enable signal (OE) will enable both bytes of program memory at once to form a 16-bit instruction word. The Chip Enable signal (CE) is active at any time that the microcontroller accesses external memory, whether reading or writing; it is inactive (asserted high) whenever the device is in SLEEP mode. In Byte Select mode, JEDEC standard FLASH memories will require BA0 for the byte address line, and one I/O line to select between Byte and Word mode. The other 16-bit modes do not need BA0. JEDEC standard static RAM memories will use the UB or LB signals for byte selection.
6.2.1
16-BIT BYTE WRITE MODE
Figure 6-1 shows an example of 16-bit Byte Write mode for PIC18F8X20 devices. This mode is used for two separate 8-bit memories connected for 16-bit operation. This generally includes basic EPROM and FLASH devices. It allows Table Writes to byte-wide external memories. During a TBLWT instruction cycle, the TABLAT data is presented on the upper and lower bytes of the AD15:AD0 bus. The appropriate WRH or WRL control line is strobed on the LSb of the TBLPTR.
FIGURE 6-1:
16-BIT BYTE WRITE MODE EXAMPLE
D<7:0> (MSB) 373 A<19:0> D<15:8> A D<7:0> CE OE WR
(1)
PIC18F8X20 AD<7:0>
(LSB) A D<7:0> D<7:0> CE OE WR(1)
AD<15:8> ALE A<19:16> CE OE WRH WRL
373
Address Bus Data Bus Control Lines Note 1: This signal only applies to Table Writes. See Section 5.1 (Table Reads and Writes).
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6.2.2 16-BIT WORD WRITE MODE
Figure 6-2 shows an example of 16-bit Word Write mode for PIC18F8X20 devices. This mode is used for word-wide memories, which includes some of the EPROM and FLASH type memories. This mode allows opcode fetches and Table Reads from all forms of 16-bit memory, and Table Writes to any type of word-wide external memories. This method makes a distinction between TBLWT cycles to even or odd addresses. During a TBLWT cycle to an even address (TBLPTR<0> = 0), the TABLAT data is transferred to a holding latch and the external address data bus is tri-stated for the data portion of the bus cycle. No write signals are activated. During a TBLWT cycle to an odd address (TBLPTR<0> = 1), the TABLAT data is presented on the upper byte of the AD15:AD0 bus. The contents of the holding latch are presented on the lower byte of the AD15:AD0 bus. The WRH signal is strobed for each write cycle; the WRL pin is unused. The signal on the BA0 pin indicates the LSbit of TBLPTR, but it is left unconnected. Instead, the UB and LB signals are active to select both bytes. The obvious limitation to this method is that the Table Write must be done in pairs on a specific word boundary to correctly write a word location.
FIGURE 6-2:
16-BIT WORD WRITE MODE EXAMPLE
A<20:1> D<15:0>
PIC18F8X20 AD<7:0>
373
A D<15:0> CE
JEDEC Word EPROM Memory
AD<15:8> 373 ALE A<19:16> CE OE WRH
OE
WR(1)
Address Bus Data Bus Control Lines Note 1: This signal only applies to Table Writes. See Section 5.1 (Table Reads and Writes).
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6.2.3 16-BIT BYTE SELECT MODE
Figure 6-3 shows an example of 16-bit Byte Select mode for PIC18F8X20 devices. This mode allows Table Write operations to word-wide external memories with byte-selection capability. This generally includes both word-wide FLASH and SRAM devices. During a TBLWT cycle, the TABLAT data is presented on the upper and lower byte of the AD15:AD0 bus. The WRH signal is strobed for each write cycle; the WRL pin is not used. The BA0 or UB/LB signals are used to select the byte to be written, based on the Least Significant bit of the TBLPTR register. FLASH and SRAM devices use different control signal combinations to implement Byte Select mode. JEDEC standard FLASH memories require that a controller I/O port pin be connected to the memory's BYTE/WORD pin to provide the select signal. They also use the BA0 signal from the controller as a byte address. JEDEC standard static RAM memories, on the other hand, use the UB or LB signals to select the byte.
FIGURE 6-3:
16-BIT BYTE SELECT MODE EXAMPLE
PIC18F8X20 AD<7:0>
373
A<20:1>
A
JEDEC Word FLASH Memory D<15:0> D<15:0>
AD<15:8> 373 ALE A<19:16> OE WRH WRL BA0 I/O
138(2)
CE A0 BYTE/WORD OE WR(1)
A<20:1>
A
JEDEC Word SRAM Memory D<15:0>
LB UB
CE LB UB OE
D<15:0> WR(1)
Address Bus Data Bus Control Lines Note 1: This signal only applies to Table Writes. See Section 5.1 (Table Reads and Writes). 2: De-multiplexing is only required when multiple memory devices are accessed.
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6.2.4 16-BIT MODE TIMING
The presentation of control signals on the external memory bus is different for the various Operating modes. Typical signal timing diagrams are shown in Figure 6-4 through Figure 6-6.
FIGURE 6-4:
Apparent Q Actual Q A<19:16> AD<15:0> BA0 ALE OE WRH WRL CE Memory Cycle Instruction Execution '1' '1' '0'
EXTERNAL MEMORY BUS TIMING FOR TBLRD (MICROPROCESSOR MODE)
Q1 Q1 Q2 Q2 00h 3AABh 0E55h CF33h Q3 Q3 Q4 Q4 Q1 Q1 Q2 Q2 Q3 Q3 Q4 Q4 Q4 Q1 0Ch 9256h Q4 Q2 Q4 Q3 Q4 Q4
'1' '1' '0' 1 TCY Wait Opcode Fetch MOVLW 55h from 007556h TBLRD Cycle1 Table Read of 92h from 199E67h TBLRD Cycle2
FIGURE 6-5:
Q1
EXTERNAL MEMORY BUS TIMING FOR TBLRD (EXTENDED MICROCONTROLLER MODE)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
A<19:16> AD<15:0> CE ALE OE Memory Cycle Instruction Execution Opcode Fetch TBLRD * from 000100h INST(PC-2) Opcode Fetch MOVLW 55h from 000102h TBLRD Cycle1 CF33h
0Ch 9256h
TBLRD 92h from 199E67h
Opcode Fetch ADDLW 55h from 000104h MOVLW
TBLRD Cycle2
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FIGURE 6-6:
Q1
EXTERNAL MEMORY BUS TIMING FOR SLEEP (MICROPROCESSOR MODE)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
A<19:16> AD<15:0> CE ALE OE Memory Cycle 3AAAh
00h 0003h
00h 0E55h
3AABh
Opcode Fetch SLEEP from 007554h INST(PC-2)
Opcode Fetch MOVLW 55h from 007556h SLEEP
SLEEP Mode, Bus Inactive
Instruction Execution
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NOTES:
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7.0 DATA EEPROM MEMORY
7.1 EEADR and EEADRH
The Data EEPROM is readable and writable during normal operation over the entire VDD range. The data memory is not directly mapped in the register file space. Instead, it is indirectly addressed through the Special Function Registers (SFR). There are five SFRs used to read and write the program and data EEPROM memory. These registers are: * * * * * EECON1 EECON2 EEDATA EEADRH EEADR The address register pair can address up to a maximum of 1024 bytes of data EEPROM. The two MSbits of the address are stored in EEADRH, while the remaining eight LSbits are stored in EEADR. The six Most Significant bits of EEADRH are unused, and are read as `0'.
7.2
EECON1 and EECON2 Registers
EECON1 is the control register for EEPROM memory accesses. EECON2 is not a physical register. Reading EECON2 will read all `0's. The EECON2 register is used exclusively in the EEPROM write sequence. Control bits RD and WR initiate read and write operations, respectively. These bits cannot be cleared, only set, in software. They are cleared in hardware at the completion of the read or write operation. The inability to clear the WR bit in software prevents the accidental or premature termination of a write operation. The WREN bit, when set, will allow a write operation. On power-up, the WREN bit is clear. The WRERR bit is set when a write operation is interrupted by a MCLR Reset, or a WDT Time-out Reset during normal operation. In these situations, the user can check the WRERR bit and rewrite the location. It is necessary to reload the data and address registers (EEDATA and EEADR), due to the RESET condition forcing the contents of the registers to zero. Note: Interrupt flag bit, EEIF in the PIR2 register, is set when write is complete. It must be cleared in software.
The EEPROM data memory allows byte read and write. When interfacing to the data memory block, EEDATA holds the 8-bit data for read/write. EEADR and EEADRH hold the address of the EEPROM location being accessed. These devices have 1024 bytes of data EEPROM with an address range from 00h to 3FFh. The EEPROM data memory is rated for high erase/write cycles. A byte write automatically erases the location and writes the new data (erase-before-write). The write time is controlled by an on-chip timer. The write time will vary with voltage and temperature, as well as from chip to chip. Please refer to parameter D122 (Electrical Characteristics, Section 26.0) for exact limits.
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PIC18FXX20
REGISTER 7-1: EECON1 REGISTER (ADDRESS FA6h)
R/W-x EEPGD bit 7 bit 7 EEPGD: FLASH Program/Data EEPROM Memory Select bit 1 = Access FLASH Program memory 0 = Access Data EEPROM memory CFGS: FLASH Program/Data EEPROM or Configuration Select bit 1 = Access Configuration or Calibration registers 0 = Access FLASH Program or Data EEPROM memory Unimplemented: Read as '0' FREE: FLASH Row Erase Enable bit 1 = Erase the program memory row addressed by TBLPTR on the next WR command (cleared by completion of erase operation) 0 = Perform write only WRERR: FLASH Program/Data EEPROM Error Flag bit 1 = A write operation is prematurely terminated (any MCLR or any WDT Reset during self-timed programming in normal operation) 0 = The write operation completed Note: bit 2 When a WRERR occurs, the EEPGD or FREE bits are not cleared. This allows tracing of the error condition. R/W-x CFGS U-0 -- R/W-0 FREE R/W-x WRERR R/W-0 WREN R/S-0 WR R/S-0 RD bit 0
bit 6
bit 5 bit 4
bit 3
WREN: FLASH Program/Data EEPROM Write Enable bit 1 = Allows write cycles to FLASH Program/Data EEPROM 0 = Inhibits write cycles to FLASH Program/Data EEPROM WR: Write Control bit 1 = Initiates a Data EEPROM erase/write cycle, or a program memory erase cycle or write cycle. (The operation is self-timed and the bit is cleared by hardware once write is complete. The WR bit can only be set (not cleared) in software.) 0 = Write cycle to the EEPROM is complete RD: Read Control bit 1 = Initiates an EEPROM read (Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared) in software. RD bit cannot be set when EEPGD = 1.) 0 = Does not initiate an EEPROM read Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 1
bit 0
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7.3 Reading the Data EEPROM Memory
control bit (EECON1<6>), and then set the RD control bit (EECON1<0>). The data is available for the very next instruction cycle; therefore, the EEDATA register can be read by the next instruction. EEDATA will hold this value until another read operation, or until it is written to by the user (during a write operation).
To read a data memory location, the user must write the address to the EEADRH:EEADR register pair, clear the EEPGD control bit (EECON1<7>), clear the CFGS
EXAMPLE 7-1:
MOVLW MOVWF MOVLW MOVWF BCF BCF BSF MOVF
DATA EEPROM READ
DATA_EE_ADDRH EEADRH DATA_EE_ADDR EEADR EECON1, EEPGD EECON1, CFGS EECON1, RD EEDATA, W ; ; ; ; ; ; ; ; Upper bits of Data Memory Address to read Lower bits of Data Memory Address to read Point to DATA memory Access EEPROM EEPROM Read W = EEDATA
7.4
Writing to the Data EEPROM Memory
To write an EEPROM data location, the address must first be written to the EEADRH:EEADR register pair and the data written to the EEDATA register. Then the sequence in Example 7-2 must be followed to initiate the write cycle. The write will not initiate if the above sequence is not exactly followed (write 55h to EECON2, write AAh to EECON2, then set WR bit) for each byte. It is strongly recommended that interrupts be disabled during this code segment. Additionally, the WREN bit in EECON1 must be set to enable writes. This mechanism prevents accidental writes to data EEPROM due to unexpected code exe-
cution (i.e., runaway programs). The WREN bit should be kept clear at all times, except when updating the EEPROM. The WREN bit is not cleared by hardware After a write sequence has been initiated, EECON1, EEADRH, EEADR and EEDATA cannot be modified. The WR bit will be inhibited from being set unless the WREN bit is set. The WREN bit must be set on a previous instruction. Both WR and WREN cannot be set with the same instruction. At the completion of the write cycle, the WR bit is cleared in hardware and the EEPROM Write Complete Interrupt Flag bit (EEIF) is set. The user may either enable this interrupt, or poll this bit. EEIF must be cleared by software.
EXAMPLE 7-2:
DATA EEPROM WRITE
MOVLW MOVWF MOVLW MOVWF MOVLW MOVWF BCF BCF BSF BCF MOVLW MOVWF MOVLW MOVWF BSF BSF DATA_EE_ADDRH EEADRH DATA_EE_ADDR EEADR DATA_EE_DATA EEDATA EECON1, EEPGD EECON1,CFGS EECON1, WREN INTCON, GIE 55h EECON2 AAh EECON2 EECON1, WR INTCON, GIE ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Upper bits of Data Memory Address to write Lower bits of Data Memory Address to write Data Memory Value to write Point to DATA memory Access EEPROM Enable writes Disable Interrupts Write 55h Write AAh Set WR bit to begin write Enable Interrupts
Required Sequence
BCF
EECON1, WREN
; User code execution ; Disable writes on write complete (EEIF set)
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7.5 Write Verify 7.8 Using the Data EEPROM
Depending on the application, good programming practice may dictate that the value written to the memory should be verified against the original value. This should be used in applications where excessive writes can stress bits near the specification limit. The data EEPROM is a high endurance, byte addressable array that has been optimized for the storage of frequently changing information (e.g., program variables or other data that are updated often). Frequently changing values will typically be updated more often than specification D124. If this is not the case, an array refresh must be performed. For this reason, variables that change infrequently (such as constants, IDs, calibration, etc.) should be stored in FLASH program memory. A simple data EEPROM refresh routine is shown in Example 7-3. Note: If data EEPROM is only used to store constants and/or data that changes rarely, an array refresh is likely not required. See specification D124.
7.6
Protection Against Spurious Write
There are conditions when the device may not want to write to the data EEPROM memory. To protect against spurious EEPROM writes, various mechanisms have been built-in. On power-up, the WREN bit is cleared. Also, the Power-up Timer (72 ms duration) prevents EEPROM write. The write initiate sequence and the WREN bit together help prevent an accidental write during brown-out, power glitch, or software malfunction.
7.7
Operation During Code Protect
Data EEPROM memory has its own code protect mechanism. External Read and Write operations are disabled if either of these mechanisms are enabled. The microcontroller itself can both read and write to the internal Data EEPROM, regardless of the state of the code protect configuration bit. Refer to "Special Features of the CPU" (Section 23.0) for additional information.
EXAMPLE 7-3:
clrf clrf bcf bcf bcf bsf Loop bsf movlw movwf movlw movwf bsf btfsc bra incfsz bra incfsz bra bcf bsf
DATA EEPROM REFRESH ROUTINE
EEADR EEADRH EECON1,CFGS EECON1,EEPGD INTCON,GIE EECON1,WREN EECON1,RD 55h EECON2 AAh EECON2 EECON1,WR EECON1,WR $-2 EEADR,F Loop EEADRH, F Loop EECON1,WREN INTCON,GIE ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Start at address 0 Set for memory Set for Data EEPROM Disable interrupts Enable writes Loop to refresh array Read current address Write 55h Write AAh Set WR bit to begin write Wait for write to complete Increment Not zero, Increment Not zero, address do it again the high address do it again
; Disable writes ; Enable interrupts
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TABLE 7-1:
Name INTCON EEADRH EEADR EEDATA EECON2 EECON1 IPR2 PIR2 PIE2 Legend:
REGISTERS ASSOCIATED WITH DATA EEPROM MEMORY
Bit 7 Bit 6 Bit 5 Bit 4 INT0IE -- Bit 3 RBIE -- Bit 2 TMR0IF -- Bit 1 INT0IF Bit 0 RBIF Value on: POR, BOR 0000 0000 0000 0000 0000 0000 -- WREN LVDIP LVDIF LVDIE WR TMR3IP TMR3IF TMR3IE RD CCP2IP CCP2IF CCP2IE xx-0 x000 ---1 1111 ---0 0000 ---0 0000 -- -- -- -- FREE EEIP EEIF EEIE WRERR BCLIP BCLIF BCLIE Value on all other RESETS 0000 0000 ---- --00 0000 0000 0000 0000 -- uu-0 u000 ---1 1111 ---0 0000 ---0 0000
GIE/GIEH --
PEIE/GIEL TMR0IE -- --
EE Addr Register High ---- --00
EEPROM Address Register EEPROM Data Register EEPROM Control Register2 (not a physical register) EEPGD -- -- -- CFGS CMIP CMIF CMIE
x = unknown, u = unchanged, r = reserved, - = unimplemented, read as '0'. Shaded cells are not used during FLASH/EEPROM access.
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NOTES:
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8.0
8.1
8 X 8 HARDWARE MULTIPLIER
Introduction
8.2
Operation
An 8 x 8 hardware multiplier is included in the ALU of the PIC18FXX20 devices. By making the multiply a hardware operation, it completes in a single instruction cycle. This is an unsigned multiply that gives a 16-bit result. The result is stored in the 16-bit product register pair (PRODH:PRODL). The multiplier does not affect any flags in the ALUSTA register. Making the 8 x 8 multiplier execute in a single cycle gives the following advantages: * Higher computational throughput * Reduces code size requirements for multiply algorithms The performance increase allows the device to be used in applications previously reserved for Digital Signal Processors. Table 8-1 shows a performance comparison between enhanced devices using the single cycle hardware multiply, and performing the same function without the hardware multiply.
Example 8-1 shows the sequence to do an 8 x 8 unsigned multiply. Only one instruction is required when one argument of the multiply is already loaded in the WREG register. Example 8-2 shows the sequence to do an 8 x 8 signed multiply. To account for the sign bits of the arguments, each argument's Most Significant bit (MSb) is tested and the appropriate subtractions are done.
EXAMPLE 8-1:
MOVF MULWF ARG1, W ARG2
8 x 8 UNSIGNED MULTIPLY ROUTINE
; ; ARG1 * ARG2 -> ; PRODH:PRODL
EXAMPLE 8-2:
MOVF MULWF BTFSC SUBWF MOVF BTFSC SUBWF ARG1, ARG2 W
8 x 8 SIGNED MULTIPLY ROUTINE
; ; ; ; ; ARG1 * ARG2 -> PRODH:PRODL Test Sign Bit PRODH = PRODH - ARG1
ARG2, SB PRODH, F ARG2, W ARG1, SB PRODH, F
; Test Sign Bit ; PRODH = PRODH ; - ARG2
TABLE 8-1:
Routine
PERFORMANCE COMPARISON
Multiply Method Without hardware multiply Hardware multiply Without hardware multiply Hardware multiply Without hardware multiply Hardware multiply Without hardware multiply Hardware multiply Program Memory (Words) 13 1 33 6 21 28 52 35 Cycles (Max) 69 1 91 6 242 28 254 40 Time @ 40 MHz 6.9 s 100 ns 9.1 s 600 ns 24.2 s 2.8 s 25.4 s 4.0 s @ 10 MHz 27.6 s 400 ns 36.4 s 2.4 s 96.8 s 11.2 s 102.6 s 16.0 s @ 4 MHz 69 s 1 s 91 s 6 s 242 s 28 s 254 s 40 s
8 x 8 unsigned 8 x 8 signed 16 x 16 unsigned 16 x 16 signed
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Example 8-3 shows the sequence to do a 16 x 16 unsigned multiply. Equation 8-1 shows the algorithm that is used. The 32-bit result is stored in four registers, RES3:RES0.
EQUATION 8-2:
16 x 16 SIGNED MULTIPLICATION ALGORITHM
EQUATION 8-1:
16 x 16 UNSIGNED MULTIPLICATION ALGORITHM
ARG1H:ARG1L * ARG2H:ARG2L (ARG1H * ARG2H * 216) + (ARG1H * ARG2L * 28) + (ARG1L * ARG2H * 28) + (ARG1L * ARG2L)
RES3:RES0
= =
RES3:RES0 = ARG1H:ARG1L * ARG2H:ARG2L = (ARG1H * ARG2H * 216) + (ARG1H * ARG2L * 28) + (ARG1L * ARG2H * 28) + (ARG1L * ARG2L)+ (-1 * ARG2H<7> * ARG1H:ARG1L * 216) + (-1 * ARG1H<7> * ARG2H:ARG2L * 216)
EXAMPLE 8-4:
MOVF MULWF MOVFF MOVFF ; MOVF MULWF MOVFF MOVFF ; MOVF MULWF MOVF ADDWF MOVF ADDWFC CLRF ADDWFC ; MOVF MULWF MOVF ADDWF MOVF ADDWFC CLRF ADDWFC ; BTFSS BRA MOVF SUBWF MOVF SUBWFB ; SIGN_ARG1 BTFSS BRA MOVF SUBWF MOVF SUBWFB ; CONT_CODE :
16 x 16 SIGNED MULTIPLY ROUTINE
; ARG1L * ARG2L -> ; PRODH:PRODL ; ;
EXAMPLE 8-3:
MOVF MULWF MOVFF MOVFF ; MOVF MULWF MOVFF MOVFF ; MOVF MULWF MOVF ADDWF MOVF ADDWFC CLRF ADDWFC ; MOVF MULWF MOVF ADDWF MOVF ADDWFC CLRF ADDWFC
16 x 16 UNSIGNED MULTIPLY ROUTINE
ARG1L, W ARG2L PRODH, RES1 PRODL, RES0 ARG1H, W ARG2H PRODH, RES3 PRODL, RES2 ARG1L, W ARG2H PRODL, RES1, PRODH, RES2, WREG RES3, W F W F F
ARG1L, W ARG2L
; ARG1L * ARG2L -> ; PRODH:PRODL PRODH, RES1 ; PRODL, RES0 ;
ARG1H, W ARG2H
; ARG1H * ARG2H -> ; PRODH:PRODL PRODH, RES3 ; PRODL, RES2 ;
; ARG1H * ARG2H -> ; PRODH:PRODL ; ;
ARG1L, W ARG2H PRODL, RES1, PRODH, RES2, WREG RES3, W F W F F
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
ARG1L * ARG2H -> PRODH:PRODL Add cross products
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
ARG1L * ARG2H -> PRODH:PRODL Add cross products
ARG1H, W ARG2L PRODL, RES1, PRODH, RES2, WREG RES3, W F W F F
ARG1H * ARG2L -> PRODH:PRODL Add cross products
ARG1H, W ARG2L PRODL, RES1, PRODH, RES2, WREG RES3, W F W F F
ARG1H * ARG2L -> PRODH:PRODL Add cross products
Example 8-4 shows the sequence to do a 16 x 16 signed multiply. Equation 8-2 shows the algorithm used. The 32-bit result is stored in four registers, RES3:RES0. To account for the sign bits of the arguments, each argument pairs Most Significant bit (MSb) is tested and the appropriate subtractions are done.
ARG2H, 7 SIGN_ARG1 ARG1L, W RES2 ARG1H, W RES3
; ARG2H:ARG2L neg? ; no, check ARG1 ; ; ;
ARG1H, 7 CONT_CODE ARG2L, W RES2 ARG2H, W RES3
; ARG1H:ARG1L neg? ; no, done ; ; ;
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9.0 INTERRUPTS
The PIC18FXX20 devices have multiple interrupt sources and an interrupt priority feature that allows each interrupt source to be assigned a high or a low priority level. The high priority interrupt vector is at 000008h, while the low priority interrupt vector is at 000018h. High priority interrupt events will override any low priority interrupts that may be in progress. There are thirteen registers which are used to control interrupt operation. They are: * * * * * * * RCON INTCON INTCON2 INTCON3 PIR1, PIR2, PIR3 PIE1, PIE2, PIE3 IPR1, IPR2, IPR3 When the IPEN bit is cleared (default state), the interrupt priority feature is disabled and interrupts are compatible with PICmicro(R) mid-range devices. In Compatibility mode, the interrupt priority bits for each source have no effect. INTCON<6> is the PEIE bit, which enables/disables all peripheral interrupt sources. INTCON<7> is the GIE bit, which enables/disables all interrupt sources. All interrupts branch to address 000008h in Compatibility mode. When an interrupt is responded to, the Global Interrupt Enable bit is cleared to disable further interrupts. If the IPEN bit is cleared, this is the GIE bit. If interrupt priority levels are used, this will be either the GIEH or GIEL bit. High priority interrupt sources can interrupt a low priority interrupt. The return address is pushed onto the stack and the PC is loaded with the interrupt vector address (000008h or 000018h). Once in the Interrupt Service Routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. The interrupt flag bits must be cleared in software before re-enabling interrupts to avoid recursive interrupts. The "return from interrupt" instruction, RETFIE, exits the interrupt routine and sets the GIE bit (GIEH or GIEL if priority levels are used), which re-enables interrupts. For external interrupt events, such as the INT pins or the PORTB input change interrupt, the interrupt latency will be three to four instruction cycles. The exact latency is the same for one or two-cycle instructions. Individual interrupt flag bits are set, regardless of the status of their corresponding enable bit or the GIE bit.
It is recommended that the Microchip header files, supplied with MPLAB(R) IDE, be used for the symbolic bit names in these registers. This allows the assembler/compiler to automatically take care of the placement of these bits within the specified register. Each interrupt source has three bits to control its operation. The functions of these bits are: * Flag bit to indicate that an interrupt event occurred * Enable bit that allows program execution to branch to the interrupt vector address when the flag bit is set * Priority bit to select high priority or low priority The interrupt priority feature is enabled by setting the IPEN bit (RCON<7>). When interrupt priority is enabled, there are two bits which enable interrupts globally. Setting the GIEH bit (INTCON<7>) enables all interrupts that have the priority bit set. Setting the GIEL bit (INTCON<6>) enables all interrupts that have the priority bit cleared. When the interrupt flag, enable bit and appropriate global interrupt enable bit are set, the interrupt will vector immediately to address 000008h or 000018h, depending on the priority level. Individual interrupts can be disabled through their corresponding enable bits.
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FIGURE 9-1: INTERRUPT LOGIC
Wake-up if in SLEEP mode
TMR0IF TMR0IE TMR0IP RBIF RBIE RBIP INT0IF INT0IE INT1IF INT1IE INT1IP INT2IF INT2IE INT2IP
Peripheral Interrupt Flag bit Peripheral Interrupt Enable bit Peripheral Interrupt Priority bit TMR1IF TMR1IE TMR1IP XXXXIF XXXXIE XXXXIP Additional Peripheral Interrupts High Priority Interrupt Generation Low Priority Interrupt Generation
Interrupt to CPU Vector to Location 0008h
GIEH/GIE IPE IPEN GIEL/PEIE IPEN
Peripheral Interrupt Flag bit Peripheral Interrupt Enable bit Peripheral Interrupt Priority bit TMR0IF TMR0IE TMR0IP RBIF RBIE RBIP Interrupt to CPU Vector to Location 0018h
TMR1IF TMR1IE TMR1IP XXXXIF XXXXIE XXXXIP
GIEL/PEIE GIE/GEIH
Additional Peripheral Interrupts
INT1IF INT1IE INT1IP INT2IF INT2IE INT2IP
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9.1 INTCON Registers
Note: The INTCON Registers are readable and writable registers, which contain various enable, priority and flag bits. Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature allows for software polling.
REGISTER 9-1:
INTCON REGISTER
R/W-0 GIE/GIEH bit 7 R/W-0 PEIE/GIEL R/W-0 TMR0IE R/W-0 INT0IE R/W-0 RBIE R/W-0 TMR0IF R/W-0 INT0IF R/W-x RBIF bit 0
bit 7
GIE/GIEH: Global Interrupt Enable bit When IPEN (RCON<7>) = 0: 1 = Enables all unmasked interrupts 0 = Disables all interrupts When IPEN (RCON<7>) = 1: 1 = Enables all high priority interrupts 0 = Disables all interrupts PEIE/GIEL: Peripheral Interrupt Enable bit When IPEN (RCON<7>) = 0: 1 = Enables all unmasked peripheral interrupts 0 = Disables all peripheral interrupts When IPEN (RCON<7>) = 1: 1 = Enables all low priority peripheral interrupts 0 = Disables all low priority peripheral interrupts TMR0IE: TMR0 Overflow Interrupt Enable bit 1 = Enables the TMR0 overflow interrupt 0 = Disables the TMR0 overflow interrupt INT0IE: INT0 External Interrupt Enable bit 1 = Enables the INT0 external interrupt 0 = Disables the INT0 external interrupt RBIE: RB Port Change Interrupt Enable bit 1 = Enables the RB port change interrupt 0 = Disables the RB port change interrupt TMR0IF: TMR0 Overflow Interrupt Flag bit 1 = TMR0 register has overflowed (must be cleared in software) 0 = TMR0 register did not overflow INT0IF: INT0 External Interrupt Flag bit 1 = The INT0 external interrupt occurred (must be cleared in software) 0 = The INT0 external interrupt did not occur RBIF: RB Port Change Interrupt Flag bit 1 = At least one of the RB7:RB4 pins changed state (must be cleared in software) 0 = None of the RB7:RB4 pins have changed state Note: A mismatch condition will continue to set this bit. Reading PORTB will end the mismatch condition and allow the bit to be cleared.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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REGISTER 9-2: INTCON2 REGISTER
R/W-1 RBPU bit 7 bit 7 RBPU: PORTB Pull-up Enable bit 1 = All PORTB pull-ups are disabled 0 = PORTB pull-ups are enabled by individual port latch values INTEDG0:External Interrupt0 Edge Select bit 1 = Interrupt on rising edge 0 = Interrupt on falling edge INTEDG1: External Interrupt1 Edge Select bit 1 = Interrupt on rising edge 0 = Interrupt on falling edge INTEDG2: External Interrupt2 Edge Select bit 1 = Interrupt on rising edge 0 = Interrupt on falling edge INTEDG2: External Interrupt3 Edge Select bit 1 = Interrupt on rising edge 0 = Interrupt on falling edge TMR0IP: TMR0 Overflow Interrupt Priority bit 1 = High priority 0 = Low priority INT3IP: INT3 External Interrupt Priority bit 1 = High priority 0 = Low priority RBIP: RB Port Change Interrupt Priority bit 1 = High priority 0 = Low priority Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/W-1 INTEDG0 R/W-1 INTEDG1 R/W-1 INTEDG2 R/W-1 INTEDG3 R/W-1 TMR0IP R/W-1 INT3IP R/W-1 RBIP bit 0
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note:
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature allows for software polling.
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REGISTER 9-3: INTCON3 REGISTER
R/W-1 INT2IP bit 7 bit 7 INT2IP: INT2 External Interrupt Priority bit 1 = High priority 0 = Low priority INT1IP: INT1 External Interrupt Priority bit 1 = High priority 0 = Low priority INT3IE: INT3 External Interrupt Enable bit 1 = Enables the INT3 external interrupt 0 = Disables the INT3 external interrupt INT2IE: INT2 External Interrupt Enable bit 1 = Enables the INT2 external interrupt 0 = Disables the INT2 external interrupt INT1IE: INT1 External Interrupt Enable bit 1 = Enables the INT1 external interrupt 0 = Disables the INT1 external interrupt INT3IF: INT3 External Interrupt Flag bit 1 = The INT3 external interrupt occurred (must be cleared in software) 0 = The INT3 external interrupt did not occur INT2IF: INT2 External Interrupt Flag bit 1 = The INT2 external interrupt occurred (must be cleared in software) 0 = The INT2 external interrupt did not occur INT1IF: INT1 External Interrupt Flag bit 1 = The INT1 external interrupt occurred (must be cleared in software) 0 = The INT1 external interrupt did not occur Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/W-1 INT1IP R/W-0 INT3IE R/W-0 INT2IE R/W-0 INT1IE R/W-0 INT3IF R/W-0 INT2IF R/W-0 INT1IF bit 0
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note:
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature allows for software polling.
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9.2 PIR Registers
The PIR registers contain the individual flag bits for the peripheral interrupts. Due to the number of peripheral interrupt sources, there are three Peripheral Interrupt Flag Registers (PIR1, PIR2 and PIR3). Note 1: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit, GIE (INTCON<7>). 2: User software should ensure the appropriate interrupt flag bits are cleared prior to enabling an interrupt, and after servicing that interrupt.
REGISTER 9-4:
PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
R/W-0 PSPIF bit 7
(1)
R/W-0 ADIF
R-0 RC1IF
R-0 TX1IF
R/W-0 SSPIF
R/W-0 CCP1IF
R/W-0 TMR2IF
R/W-0 TMR1IF bit 0
bit 7
PSPIF: Parallel Slave Port Read/Write Interrupt Flag bit(1) 1 = A read or a write operation has taken place (must be cleared in software) 0 = No read or write has occurred ADIF: A/D Converter Interrupt Flag bit 1 = An A/D conversion completed (must be cleared in software) 0 = The A/D conversion is not complete RC1IF: USART1 Receive Interrupt Flag bit 1 = The USART1 receive buffer, RCREG, is full (cleared when RCREG is read) 0 = The USART1 receive buffer is empty TX1IF: USART Transmit Interrupt Flag bit 1 = The USART1 transmit buffer, TXREG, is empty (cleared when TXREG is written) 0 = The USART1 transmit buffer is full SSPIF: Master Synchronous Serial Port Interrupt Flag bit 1 = The transmission/reception is complete (must be cleared in software) 0 = Waiting to transmit/receive CCP1IF: CCP1 Interrupt Flag bit Capture mode: 1 = A TMR1 register capture occurred (must be cleared in software) 0 = No TMR1 register capture occurred Compare mode: 1 = A TMR1 register compare match occurred (must be cleared in software) 0 = No TMR1 register compare match occurred PWM mode: Unused in this mode TMR2IF: TMR2 to PR2 Match Interrupt Flag bit 1 = TMR2 to PR2 match occurred (must be cleared in software) 0 = No TMR2 to PR2 match occurred TMR1IF: TMR1 Overflow Interrupt Flag bit 1 = TMR1 register overflowed (must be cleared in software) 0 = MR1 register did not overflow Note 1: Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown Enabled only in Microcontroller mode for PIC18F8X20 devices.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 9-5: PIR2: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 2
U-0 -- bit 7 bit 7 bit 6 Unimplemented: Read as '0' CMIF: Comparator Interrupt Flag bit 1 = The comparator input has changed (must be cleared in software) 0 = The comparator input has not changed Unimplemented: Read as '0' EEIF: Data EEPROM/FLASH Write Operation Interrupt Flag bit 1 = The write operation is complete (must be cleared in software) 0 = The write operation is not complete, or has not been started BCLIF: Bus Collision Interrupt Flag bit 1 = A bus collision occurred while the SSP module (configured in I2C Master mode) was transmitting (must be cleared in software) 0 = No bus collision occurred LVDIF: Low Voltage Detect Interrupt Flag bit 1 = A low voltage condition occurred (must be cleared in software) 0 = The device voltage is above the Low Voltage Detect trip point TMR3IF: TMR3 Overflow Interrupt Flag bit 1 = TMR3 register overflowed (must be cleared in software) 0 = TMR3 register did not overflow CCP2IF: CCP2 Interrupt Flag bit Capture mode: 1 = A TMR1 or TMR3 register capture occurred (must be cleared in software) 0 = No TMR1 or TMR3 register capture occurred Compare mode: 1 = A TMR1 or TMR3 register compare match occurred (must be cleared in software) 0 = No TMR1 or TMR3 register compare match occurred PWM mode: Unused in this mode Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/W-0 CMIF U-0 -- R/W-0 EEIF R/W-0 BCLIF R/W-0 LVDIF R/W-0 TMR3IF R/W-0 CCP2IF bit 0
bit 5 bit 4
bit 3
bit 2
bit 1
bit 0
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PIC18FXX20
REGISTER 9-6: PIR3: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 3
U-0 -- bit 7 bit 7- 6 bit 5 Unimplemented: Read as '0' RC2IF: USART2 Receive Interrupt Flag bit 1 = The USART2 receive buffer, RCREG, is full (cleared when RCREG is read) 0 = The USART2 receive buffer is empty TX2IF: USART2 Transmit Interrupt Flag bit 1 = The USART2 transmit buffer, TXREG, is empty (cleared when TXREG is written) 0 = The USART2 transmit buffer is full TMR4IF: TMR3 Overflow Interrupt Flag bit 1 = TMR4 register overflowed (must be cleared in software) 0 = TMR4 register did not overflow CCP2IF: CCPx Interrupt Flag bit (CCP Modules 3, 4 and 5) Capture mode: 1 = A TMR1 or TMR3 register capture occurred (must be cleared in software) 0 = No TMR1 or TMR3 register capture occurred Compare mode: 1 = A TMR1 or TMR3 register compare match occurred (must be cleared in software) 0 = No TMR1 or TMR3 register compare match occurred PWM mode: Unused in this mode Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown U-0 -- R-0 RC2IF R-0 TX2IF R/W-0 TMR4IF R/W-0 CCP5IF R/W-0 CCP4IF R/W-0 CCP3IF bit 0
bit 4
bit 3
bit 2-0
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9.3 PIE Registers
The PIE registers contain the individual enable bits for the peripheral interrupts. Due to the number of peripheral interrupt sources, there are three Peripheral Interrupt Enable Registers (PIE1, PIE2 and PIE3). When the IPEN bit (RCON<7>) is `0', the PEIE bit must be set to enable any of these peripheral interrupts.
REGISTER 9-7:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0 PSPIE(1) bit 7 R/W-0 ADIE R/W-0 RC1IE R/W-0 TX1IE R/W-0 SSPIE R/W-0 CCP1IE R/W-0 TMR2IE R/W-0 TMR1IE bit 0
bit 7
PSPIE: Parallel Slave Port Read/Write Interrupt Enable bit(1) 1 = Enables the PSP read/write interrupt 0 = Disables the PSP read/write interrupt ADIE: A/D Converter Interrupt Enable bit 1 = Enables the A/D interrupt 0 = Disables the A/D interrupt RC1IE: USART1 Receive Interrupt Enable bit 1 = Enables the USART1 receive interrupt 0 = Disables the USART1 receive interrupt TX1IE: USART1 Transmit Interrupt Enable bit 1 = Enables the USART1 transmit interrupt 0 = Disables the USART1 transmit interrupt SSPIE: Master Synchronous Serial Port Interrupt Enable bit 1 = Enables the MSSP interrupt 0 = Disables the MSSP interrupt CCP1IE: CCP1 Interrupt Enable bit 1 = Enables the CCP1 interrupt 0 = Disables the CCP1 interrupt TMR2IE: TMR2 to PR2 Match Interrupt Enable bit 1 = Enables the TMR2 to PR2 match interrupt 0 = Disables the TMR2 to PR2 match interrupt TMR1IE: TMR1 Overflow Interrupt Enable bit 1 = Enables the TMR1 overflow interrupt 0 = Disables the TMR1 overflow interrupt Note 1: Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown Enabled only in Microcontroller mode for PIC18F8X20 devices.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 9-8: PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
U-0 -- bit 7 bit 7 bit 6 Unimplemented: Read as '0' CMIE: Comparator Interrupt Enable bit 1 = Enables the comparator interrupt 0 = Disables the comparator interrupt Unimplemented: Read as '0' EEIE: Data EEPROM/FLASH Write Operation Interrupt Enable bit 1 = Enables the write operation interrupt 0 = Disables the write operation interrupt BCLIE: Bus Collision Interrupt Enable bit 1 = Enables the bus collision interrupt 0 = Disables the bus collision interrupt LVDIE: Low Voltage Detect Interrupt Enable bit 1 = Enables the Low Voltage Detect interrupt 0 = Disables the Low Voltage Detect interrupt TMR3IE: TMR3 Overflow Interrupt Enable bit 1 = Enables the TMR3 overflow interrupt 0 = Disables the TMR3 overflow interrupt CCP2IE: CCP2 Interrupt Enable bit 1 = Enables the CCP2 interrupt 0 = Disables the CCP2 interrupt Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/W-0 CMIE U-0 -- R/W-0 EEIE R/W-0 BCLIE R/W-0 LVDIE R/W-0 TMR3IE R/W-0 CCP2IE bit 0
bit 5 bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 9-9: PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3
U-0 -- bit 7 bit 7-6 bit 5 Unimplemented: Read as '0' RC2IE: USART2 Receive Interrupt Enable bit 1 = Enables the USART2 receive interrupt 0 = Disables the USART2 receive interrupt TX2IE: USART2 Transmit Interrupt Enable bit 1 = Enables the USART2 transmit interrupt 0 = Disables the USART2 transmit interrupt TMR4IE: TMR4 to PR4 Match Interrupt Enable bit 1 = Enables the TMR4 to PR4 match interrupt 0 = Disables the TMR4 to PR4 match interrupt CCPxIE: CCPx Interrupt Enable bit (CCP Modules 3, 4 and 5) 1 = Enables the CCPx interrupt 0 = Disables the CCPx interrupt Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown U-0 -- R/W-0 RC2IE R/W-0 TX2IE R/W-0 TMR4IE R/W-0 CCP5IE R/W-0 CCP4IE R/W-0 CCP3IE bit 0
bit 4
bit 3
bit 2-0
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PIC18FXX20
9.4 IPR Registers
The IPR registers contain the individual priority bits for the peripheral interrupts. Due to the number of peripheral interrupt sources, there are three Peripheral Interrupt Priority Registers (IPR1, IPR2 and IPR3). The operation of the priority bits requires that the Interrupt Priority Enable (IPEN) bit be set.
REGISTER 9-10:
IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
R/W-1 PSPIP(1) bit 7 R/W-1 ADIP R/W-1 RC1IP R/W-1 TX1IP R/W-1 SSPIP R/W-1 CCP1IP R/W-1 TMR2IP R/W-1 TMR1IP bit 0
bit 7
PSPIP: Parallel Slave Port Read/Write Interrupt Priority bit(1) 1 = High priority 0 = Low priority ADIP: A/D Converter Interrupt Priority bit 1 = High priority 0 = Low priority RC1IP: USART1 Receive Interrupt Priority bit 1 = High priority 0 = Low priority TX1IP: USART1 Transmit Interrupt Priority bit 1 = High priority 0 = Low priority SSPIP: Master Synchronous Serial Port Interrupt Priority bit 1 = High priority 0 = Low priority CCP1IP: CCP1 Interrupt Priority bit 1 = High priority 0 = Low priority TMR2IP: TMR2 to PR2 Match Interrupt Priority bit 1 = High priority 0 = Low priority TMR1IP: TMR1 Overflow Interrupt Priority bit 1 = High priority 0 = Low priority Note 1: Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown Enabled only in Microcontroller mode for PIC18F8X20 devices.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 9-11: IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
U-0 -- bit 7 bit 7 bit 6 Unimplemented: Read as '0' CMIP: Comparator Interrupt Priority bit 1 = High priority 0 = Low priority Unimplemented: Read as '0' EEIP: Data EEPROM/FLASH Write Operation Interrupt Priority bit 1 = High priority 0 = Low priority BCLIP: Bus Collision Interrupt Priority bit 1 = High priority 0 = Low priority LVDIP: Low Voltage Detect Interrupt Priority bit 1 = High priority 0 = Low priority TMR3IP: TMR3 Overflow Interrupt Priority bit 1 = High priority 0 = Low priority CCP2IP: CCP2 Interrupt Priority bit 1 = High priority 0 = Low priority Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/W-1 CMIP U-0 -- R/W-1 EEIP R/W-1 BCLIP R/W-1 LVDIP R/W-1 TMR3IP R/W-1 CCP2IP bit 0
bit 5 bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 9-12: IPR3: PERIPHERAL INTERRUPT PRIORITY REGISTER 3
U-0 -- bit 7 bit 7-6 bit 5 Unimplemented: Read as '0' RC2IP: USART2 Receive Interrupt Priority bit 1 = High priority 0 = Low priority TX2IP: USART2 Transmit Interrupt Priority bit 1 = High priority 0 = Low priority TMR4IP: TMR4 to PR4 Match Interrupt Priority bit 1 = High priority 0 = Low priority CCPxIP: CCPx Interrupt Priority bit (CCP Modules 3, 4 and 5) 1 = High priority 0 = Low priority Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown U-0 -- R/W-1 RC2IP R/W-1 TX2IP R/W-1 TMR4IP R/W-1 CCP5IP R/W-1 CCP4IP R/W-1 CCP3IP bit 0
bit 4
bit 3
bit 2
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9.5 RCON Register
The RCON register contains the IPEN bit, which is used to enable prioritized interrupts. The functions of the other bits in this register are discussed in more detail in Section 4.14.
REGISTER 9-13:
RCON REGISTER
R/W-0 IPEN bit 7 U-0 -- U-0 -- R/W-1 RI R-1 TO R-1 PD R/W-0 POR R/W-0 BOR bit 0
bit 7
IPEN: Interrupt Priority Enable bit 1 = Enable priority levels on interrupts 0 = Disable priority levels on interrupts (PIC16 Compatibility mode) Unimplemented: Read as '0' RI: RESET Instruction Flag bit For details of bit operation, see Register 4-4 TO: Watchdog Time-out Flag bit For details of bit operation, see Register 4-4 PD: Power-down Detection Flag bit For details of bit operation, see Register 4-4 POR: Power-on Reset Status bit For details of bit operation, see Register 4-4 BOR: Brown-out Reset Status bit For details of bit operation, see Register 4-4 Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6-5 bit 4 bit 3 bit 2 bit 1 bit 0
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PIC18FXX20
9.6 INT0 Interrupt 9.7 TMR0 Interrupt
External interrupts on the RB0/INT0, RB1/INT1, RB2/INT2 and RB3/INT3 pins are edge-triggered: either rising, if the corresponding INTEDGx bit is set in the INTCON2 register, or falling, if the INTEDGx bit is clear. When a valid edge appears on the RBx/INTx pin, the corresponding flag bit, INTxF, is set. This interrupt can be disabled by clearing the corresponding enable bit, INTxE. Flag bit, INTxF, must be cleared in software in the Interrupt Service Routine before re-enabling the interrupt. All external interrupts (INT0, INT1, INT2 and INT3) can wake-up the processor from SLEEP, if bit INTxIE was set prior to going into SLEEP. If the global interrupt enable bit GIE is set, the processor will branch to the interrupt vector following wake-up. The interrupt priority for INT, INT2 and INT3 is determined by the value contained in the interrupt priority bits: INT1IP (INTCON3<6>), INT2IP (INTCON3<7>) and INT3IP (INTCON2<1>). There is no priority bit associated with INT0; it is always a high priority interrupt source. In 8-bit mode (which is the default), an overflow in the TMR0 register (FFh 00h) will set flag bit TMR0IF. In 16-bit mode, an overflow in the TMR0H:TMR0L registers (FFFFh 0000h) will set flag bit TMR0IF. The interrupt can be enabled/disabled by setting/clearing enable bit, TMR0IE (INTCON<5>). Interrupt priority for Timer0 is determined by the value contained in the interrupt priority bit, TMR0IP (INTCON2<2>). See Section 11.0 for further details on the Timer0 module.
9.8
PORTB Interrupt-on-Change
An input change on PORTB<7:4> sets flag bit RBIF (INTCON<0>). The interrupt can be enabled/disabled by setting/clearing enable bit, RBIE (INTCON<3>). Interrupt priority for PORTB interrupt-on-change is determined by the value contained in the interrupt priority bit, RBIP (INTCON2<0>).
9.9
Context Saving During Interrupts
During an interrupt, the return PC value is saved on the stack. Additionally, the WREG, STATUS and BSR registers are saved on the fast return stack. If a fast return from interrupt is not used (See Section 4.3), the user may need to save the WREG, STATUS and BSR registers in software. Depending on the user's application, other registers may also need to be saved. Example 9-1 saves and restores the WREG, STATUS and BSR registers during an Interrupt Service Routine.
EXAMPLE 9-1:
MOVWF MOVFF MOVFF ; ; USER ; MOVFF MOVF MOVFF
SAVING STATUS, WREG AND BSR REGISTERS IN RAM
; W_TEMP is in virtual bank ; STATUS_TEMP located anywhere ; BSR located anywhere
W_TEMP STATUS, STATUS_TEMP BSR, BSR_TEMP ISR CODE BSR_TEMP, BSR W_TEMP, W STATUS_TEMP,STATUS
; Restore BSR ; Restore WREG ; Restore STATUS
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10.0 I/O PORTS
10.1
Depending on the device selected, there are either seven or nine I/O ports available on PIC18FXX20 devices. Some of their pins are multiplexed with one or more alternate functions from the other peripheral features on the device. In general, when a peripheral is enabled, that pin may not be used as a general purpose I/O pin. Each port has three registers for its operation. These registers are: * TRIS register (data direction register) * PORT register (reads the levels on the pins of the device) * LAT register (output latch) The data latch (LAT register) is useful for readmodify-write operations on the value that the I/O pins are driving. A simplified version of a generic I/O port and its operation is shown in Figure 10-1.
PORTA, TRISA and LATA Registers
PORTA is a 7-bit wide, bi-directional port. The corresponding Data Direction register is TRISA. Setting a TRISA bit (= 1) will make the corresponding PORTA pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISA bit (= 0) will make the corresponding PORTA pin an output (i.e., put the contents of the output latch on the selected pin). Reading the PORTA register reads the status of the pins, whereas writing to it will write to the port latch. The Data Latch register (LATA) is also memory mapped. Read-modify-write operations on the LATA register, read and write the latched output value for PORTA. The RA4 pin is multiplexed with the Timer0 module clock input to become the RA4/T0CKI pin. The RA4/T0CKI pin is a Schmitt Trigger input and an open drain output. All other RA port pins have TTL input levels and full CMOS output drivers. The RA6 pin is only enabled as a general I/O pin in ECIO and RCIO Oscillator modes. The other PORTA pins are multiplexed with analog inputs and the analog VREF+ and VREF- inputs. The operation of each pin is selected by clearing/setting the control bits in the ADCON1 register (A/D Control Register1). Note: On a Power-on Reset, RA5 and RA3:RA0 are configured as analog inputs and read as `0'. RA6 and RA4 are configured as digital inputs.
FIGURE 10-1:
SIMPLIFIED BLOCK DIAGRAM OF PORT/LAT/TRIS OPERATION
RD LAT TRIS D WR LAT + WR Port Q
CK Data Latch
Data Bus RD Port I/O pin
The TRISA register controls the direction of the RA pins, even when they are being used as analog inputs. The user must ensure the bits in the TRISA register are maintained set when using them as analog inputs.
EXAMPLE 10-1:
CLRF PORTA ; ; ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTA
Initialize PORTA by clearing output data latches Alternate method to clear output data latches Configure A/D for digital inputs Value used to initialize data direction Set RA<3:0> as inputs RA<5:4> as outputs
CLRF LATA
MOVLW 0x0F MOVWF ADCON1 MOVLW 0xCF
MOVWF TRISA
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FIGURE 10-2: BLOCK DIAGRAM OF RA3:RA0 AND RA5 PINS FIGURE 10-3: BLOCK DIAGRAM OF RA4/T0CKI PIN
RD LATA
Data
RD LATA Data Bus WR LATA or PORTA
Bus
D
Q VDD
WR LATA or PORTA
D CK
Q Q I/O pin(1)
CK
Q
P N
Data Latch D WR TRISA Q I/O pin(1) WR TRISA
Data Latch D CK Q Q
N VSS Schmitt Trigger Input Buffer
CK
Q
TRIS Latch
VSS Analog Input Mode
TRIS Latch
RD TRISA RD TRISA Q D TTL Input Buffer
Q
D EN EN
EN RD PORTA To A/D Converter and LVD Modules Note 1: I/O pins have protection diodes to VDD and VSS. Note 1: RD PORTA TMR0 Clock Input
I/O pins have protection diodes to VDD and VSS.
FIGURE 10-4:
BLOCK DIAGRAM OF RA6 PIN (WHEN ENABLED AS I/O)
ECRA6 or RCRA6 Enable Data Bus RD LATA D WR LATA or PORTA CK Q Q
VDD P
Data Latch D WR TRISA CK Q Q N I/O pin(1)
VSS
TRIS Latch TTL Input Buffer
RD TRISA ECRA6 or RCRA6 Enable Q D EN RD PORTA Note 1: I/O pins have protection diodes to VDD and VSS.
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TABLE 10-1:
Name RA0/AN0 RA1/AN1 RA2/AN2/VREFRA3/AN3/VREF+ RA4/T0CKI RA5/AN4/LVDIN OSC2/CLKO/RA6
PORTA FUNCTIONS
Bit# bit0 bit1 bit2 bit3 bit4 bit5 bit6 Buffer TTL TTL TTL TTL ST TTL TTL Input/output or analog input. Input/output or analog input. Input/output or analog input or VREF-. Input/output or analog input or VREF+. Input/output or external clock input for Timer0. Output is open drain type. Input/output or slave select input for synchronous serial port or analog input, or low voltage detect input. OSC2 or clock output, or I/O pin. Function
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 10-2:
Name PORTA LATA TRISA ADCON1
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Bit 6 RA6 Bit 5 RA5 Bit 4 RA4 Bit 3 RA3 Bit 2 RA2 Bit 1 RA1 Bit 0 RA0 Value on POR, BOR Value on all other RESETS
Bit 7 -- -- -- --
-x0x 0000 -u0u 0000 -xxx xxxx -uuu uuuu -111 1111 -111 1111
LATA Data Output Register PORTA Data Direction Register -- VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0
--00 0000 --00 0000
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by PORTA.
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10.2 PORTB, TRISB and LATB Registers
A mismatch condition will continue to set flag bit, RBIF. Reading PORTB will end the mismatch condition and allow flag bit RBIF to be cleared. The interrupt-on-change feature is recommended for wake-up on key depression operation and operations where PORTB is only used for the interrupt-on-change feature. Polling of PORTB is not recommended while using the interrupt-on-change feature. For PIC18F8X20 devices, RB3 can be configured by the configuration bit CCP2MX, as the alternate peripheral pin for the CCP2 module. This is only available when the device is configured in Microprocessor, Microprocessor with Boot Block, or Extended Microcontroller operating modes. The RB5 pin is used as the LVP programming pin. When the LVP configuration bit is programmed, this pin loses the I/O function and become a programming test function. Note: When LVP is enabled, the weak pull-up on RB5 is disabled.
PORTB is an 8-bit wide, bi-directional port. The corresponding Data Direction register is TRISB. Setting a TRISB bit (= 1) will make the corresponding PORTB pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISB bit (= 0) will make the corresponding PORTB pin an output (i.e., put the contents of the output latch on the selected pin). The Data Latch register (LATB) is also memory mapped. Read-modify-write operations on the LATB register, read and write the latched output value for PORTB.
EXAMPLE 10-2:
CLRF PORTB ; ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTB
Initialize PORTB by clearing output data latches Alternate method to clear output data latches Value used to initialize data direction Set RB<3:0> as inputs RB<5:4> as outputs RB<7:6> as inputs
CLRF
LATB
MOVLW 0xCF
FIGURE 10-5:
MOVWF TRISB
BLOCK DIAGRAM OF RB7:RB4 PINS
VDD Weak P Pull-up Data Latch D CK TRIS Latch D Q TTL Input Buffer Q I/O pin(1)
RBPU(2)
Each of the PORTB pins has a weak internal pull-up. A single control bit can turn on all the pull-ups. This is performed by clearing bit RBPU (INTCON2<7>). The weak pull-up is automatically turned off when the port pin is configured as an output. The pull-ups are disabled on a Power-on Reset. Note: On a Power-on Reset, these pins are configured as digital inputs.
Data Bus WR LATB or PORTB
WR TRISB
CK
Four of the PORTB pins (RB3:RB0) are the external interrupt pins, INT3 through INT0. In order to use these pins as external interrupts, the corresponding TRISB bit must be set to `1'. The other four PORTB pins (RB7:RB4) have an interrupt-on-change feature. Only pins configured as inputs can cause this interrupt to occur (i.e., any RB7:RB4 pin configured as an output is excluded from the interrupt-on-change comparison). The input pins (of RB7:RB4) are compared with the old value latched on the last read of PORTB. The "mismatch" outputs of RB7:RB4 are OR'ed together to generate the RB Port Change Interrupt with flag bit, RBIF (INTCON<0>). This interrupt can wake the device from SLEEP. The user, in the Interrupt Service Routine, can clear the interrupt in the following manner: a) Any read or write of PORTB (except with the MOVFF instruction). This will end the mismatch condition. Clear flag bit RBIF.
ST Buffer
RD TRISB
RD LATB Latch Q RD PORTB Set RBIF EN Q1 D
Q From other RB7:RB4 pins RB7:RB5 in Serial Programming Mode Note 1: 2:
D EN
RD PORTB Q3
I/O pins have diode protection to VDD and VSS. To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2<7>).
b)
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FIGURE 10-6: BLOCK DIAGRAM OF RB2:RB0 PINS
VDD RBPU(2) Data Latch D Q CK TRIS Latch D WR TRIS CK Q TTL Input Buffer I/O pin(1) Weak P Pull-up
Data Bus WR Port
RD TRIS Q RD Port D EN
INTx Schmitt Trigger Buffer Note 1: 2: RD Port
I/O pins have diode protection to VDD and VSS. To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (OPTION_REG<7>).
FIGURE 10-7:
BLOCK DIAGRAM OF RB3 PIN
VDD RBPU(2) CCP2MX CCP Output(3) 1 Weak P Pull-up VDD P Enable(3) CCP Output Data Bus WR LATB or WR PORTB Data Latch D CK TRIS Latch D WR TRISB CK Q Q N VSS TTL Input Buffer 0 I/O pin(1)
RD TRISB RD LATB Q RD PORTB D EN
RD PORTB CCP2 or INT3 Schmitt Trigger Buffer Note 1: 2: 3: CCP2MX = 0
I/O pin has diode protection to VDD and VSS. To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2<7>). For PIC18F8X20 parts, the CCP2 input/output is multiplexed with RB3 if the CCP2MX bit is enabled (= 0) in the Configuration register and the device is operating in Microprocessor, Microprocessor with Boot Block or Extended Microcontroller mode.
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TABLE 10-3:
Name RB0/INT0 RB1/INT1 RB2/INT2 RB3/CCP2(3)/INT3
PORTB FUNCTIONS
Bit# bit0 bit1 bit2 bit3 Buffer TTL/ST
(1)
Function Input/output pin or external interrupt input0. Internal software programmable weak pull-up. Input/output pin or external interrupt input1. Internal software programmable weak pull-up. Input/output pin or external interrupt input2. Internal software programmable weak pull-up. Input/output pin, or external interrupt input3. Capture2 input/Compare2 output/PWM output (when CCP2MX configuration bit is enabled, all PIC18F8X20 Operating modes except Microcontroller mode). Internal software programmable weak pull-up. Input/output pin (with interrupt-on-change). Internal software programmable weak pull-up. Input/output pin (with interrupt-on-change). Internal software programmable weak pull-up. Low voltage ICSP enable pin. Input/output pin (with interrupt-on-change). Internal software programmable weak pull-up. Serial programming clock. Input/output pin (with interrupt-on-change). Internal software programmable weak pull-up. Serial programming data.
TTL/ST(1) TTL/ST(1) TTL/ST(4)
RB4/KBI0 RB5/KBI1/PGM
bit4 bit5
TTL TTL/ST(2)
RB6/KBI2/PGC
bit6
TTL/ST(2)
RB7/KBI3/PGD
bit7
TTL/ST(2)
Legend: Note 1: 2: 3:
TTL = TTL input, ST = Schmitt Trigger input This buffer is a Schmitt Trigger input when configured as the external interrupt. This buffer is a Schmitt Trigger input when used in Serial Programming mode. RC1 is the alternate assignment for CCP2 when CCP2MX is not set (all Operating modes except Microcontroller mode). 4: This buffer is a Schmitt Trigger input when configured as the CCP2 input.
TABLE 10-4:
Name PORTB LATB TRISB INTCON INTCON2 INTCON3 Bit 7 RB7
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Bit 6 RB6 Bit 5 RB5 Bit 4 RB4 Bit 3 RB3 Bit 2 RB2 Bit 1 RB1 Bit 0 RB0 Value on POR, BOR xxxx xxxx xxxx xxxx 1111 1111 INT0IE RBIE TMR0IF TMR0IP INT3IF INT0IF INT3IP INT2IF RBIF RBIP INT1IF 0000 0000 1111 1111 1100 0000 Value on all other RESETS uuuu uuuu uuuu uuuu 1111 1111 0000 0000 1111 1111 1100 0000
LATB Data Output Register PORTB Data Direction Register GIE/ GIEH RBPU INT2IP PEIE/ GIEL INT1IP TMR0IE
INTEDG0 INTEDG1 INTEDG2 INTEDG3 INT3IE INT2IE INT1IE
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.
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10.3 PORTC, TRISC and LATC Registers
The pin override value is not loaded into the TRIS register. This allows read-modify-write of the TRIS register, without concern due to peripheral overrides. RC1 is normally configured by configuration bit, CCP2MX, as the default peripheral pin of the CCP2 module (default/erased state, CCP2MX = 1).
PORTC is an 8-bit wide, bi-directional port. The corresponding Data Direction register is TRISC. Setting a TRISC bit (= 1) will make the corresponding PORTC pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISC bit (= 0) will make the corresponding PORTC pin an output (i.e., put the contents of the output latch on the selected pin). The Data Latch register (LATC) is also memory mapped. Read-modify-write operations on the LATC register, read and write the latched output value for PORTC. PORTC is multiplexed with several peripheral functions (Table 10-5). PORTC pins have Schmitt Trigger input buffers. When enabling peripheral functions, care should be taken in defining TRIS bits for each PORTC pin. Some peripherals override the TRIS bit to make a pin an output, while other peripherals override the TRIS bit to make a pin an input. The user should refer to the corresponding peripheral section for the correct TRIS bit settings. Note: On a Power-on Reset, these pins are configured as digital inputs.
EXAMPLE 10-3:
CLRF PORTC ; ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTC
Initialize PORTC by clearing output data latches Alternate method to clear output data latches Value used to initialize data direction Set RC<3:0> as inputs RC<5:4> as outputs RC<7:6> as inputs
CLRF
LATC
MOVLW 0xCF
MOVWF TRISC
FIGURE 10-8:
PORTC BLOCK DIAGRAM (PERIPHERAL OUTPUT OVERRIDE)
PORTC/Peripheral Out Select Peripheral Data Out 0 1
D CK Q Q
VDD P
RD LATC Data Bus WR LATC or WR PORTC
I/O pin(1) N TRIS Override Logic VSS Pin RC0 RC1 Schmitt Trigger
Q D EN
Data Latch D Q Q
TRIS OVERRIDE Override Yes Yes Peripheral Timer1 OSC for Timer1/Timer3 Timer1 OSC for Timer1/Timer3, CCP2 I/O CCP1 I/O SPI/I2C Master Clock I2C Data Out SPI Data Out USART1 Async Xmit, Sync Clock USART1 Sync Data Out
WR TRISC
CK
TRIS Latch RD TRISC Peripheral Output Enable(2)
RC2 RC3 RC4 RC5 RC6 RC7
Yes Yes Yes Yes Yes Yes
RD PORTC Peripheral Data In Note 1: I/O pins have diode protection to VDD and VSS. 2: Peripheral Output Enable is only active if peripheral select is active.
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PIC18FXX20
TABLE 10-5:
Name RC0/T1OSO/T13CKI RC1/T1OSI/CCP2(1)
PORTC FUNCTIONS
Bit# bit0 bit1 Buffer Type ST ST Function Input/output port pin, Timer1 oscillator output, or Timer1/Timer3 clock input. Input/output port pin, Timer1 oscillator input, or Capture2 input/ Compare2 output/PWM output (when CCP2MX configuration bit is disabled). Input/output port pin or Capture1 input/Compare1 output/ PWM1 output. RC3 can also be the synchronous serial clock for both SPI and I2C modes. RC4 can also be the SPI Data In (SPI mode) or Data I/O (I2C mode). Input/output port pin or Synchronous Serial Port data output. Input/output port pin, Addressable USART1 Asynchronous Transmit, or Addressable USART1 Synchronous Clock. Input/output port pin, Addressable USART1 Asynchronous Receive, or Addressable USART1 Synchronous Data.
RC2/CCP1 RC3/SCK/SCL RC4/SDI/SDA RC5/SDO RC6/TX1/CK1 RC7/RX1/DT1
bit2 bit3 bit4 bit5 bit6 bit7
ST ST ST ST ST ST
Legend: ST = Schmitt Trigger input Note 1: RB3 is the alternate assignment for CCP2 when CCP2MX is set.
TABLE 10-6:
Name PORTC LATC TRISC
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Bit 6 RC6 Bit 5 RC5 Bit 4 RC4 Bit 3 RC3 Bit 2 RC2 Bit 1 RC1 Bit 0 RC0 Value on POR, BOR xxxx xxxx xxxx xxxx 1111 1111 Value on all other RESETS uuuu uuuu uuuu uuuu 1111 1111
Bit 7 RC7
LATC Data Output Register PORTC Data Direction Register
Legend: x = unknown, u = unchanged
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PIC18FXX20
10.4 PORTD, TRISD and LATD Registers
FIGURE 10-9: PORTD BLOCK DIAGRAM IN I/O PORT MODE
PORTD is an 8-bit wide, bi-directional port. The corresponding Data Direction register is TRISD. Setting a TRISD bit (= 1) will make the corresponding PORTD pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISD bit (= 0) will make the corresponding PORTD pin an output (i.e., put the contents of the output latch on the selected pin). The Data Latch register (LATD) is also memory mapped. Read-modify-write operations on the LATD register, read and write the latched output value for PORTD. PORTD is an 8-bit port with Schmitt Trigger input buffers. Each pin is individually configurable as an input or output. Note: On a Power-on Reset, these pins are configured as digital inputs.
RD LATD Data Bus WR LATD or PORTD
D CK
Q I/O pin(1)
Data Latch D WR TRISD CK TRIS Latch RD TRISD Q Schmitt Trigger Input Buffer
PORTD is multiplexed with the system bus as the external memory interface; I/O port functions are only available when the system bus is disabled, by setting the EBDIS bit in the MEMCOM register (MEMCON<7>). When operating as the external memory interface, PORTD is the low order byte of the multiplexed address/data bus (AD7:AD0). PORTD can also be configured as an 8-bit wide microprocessor port (Parallel Slave Port) by setting control bit PSPMODE (TRISE<4>). In this mode, the input buffers are TTL. See Section 10.10 for additional information on the Parallel Slave Port (PSP).
Q
D EN EN
RD PORTD
Note 1:
I/O pins have diode protection to VDD and VSS.
EXAMPLE 10-4:
CLRF PORTD ; ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTD
Initialize PORTD by clearing output data latches Alternate method to clear output data latches Value used to initialize data direction Set RD<3:0> as inputs RD<5:4> as outputs RD<7:6> as inputs
CLRF
LATD
MOVLW 0xCF
MOVWF TRISD
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PIC18FXX20
FIGURE 10-10: PORTD BLOCK DIAGRAM IN SYSTEM BUS MODE
Q D EN EN RD PORTD
RD LATD Data Bus WR LATD or PORTD D CK Data Latch D WR TRISD CK TRIS Latch RD TRISD Bus Enable System Bus Data/TRIS Out Control Drive Bus Instruction Register Instruction Read Note 1: I/O pins have protection diodes to VDD and VSS. Q TTL Input Buffer Q Port Data 0 1 I/O pin(1)
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TABLE 10-7:
Name RD0/PSP0/AD0 RD1/PSP1/AD1 RD2/PSP2/AD2 RD3/PSP3/AD3 RD4/PSP4/AD4 RD5/PSP5/AD5 RD6/PSP6/AD6 RD7/PSP7/AD7
PORTD FUNCTIONS
Bit# bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 Buffer Type ST/TTL ST/TTL
(1) (1)
Function Input/output port pin, parallel slave port bit0 or address/data bus bit0. Input/output port pin, parallel slave port bit1 or address/data bus bit1. Input/output port pin, parallel slave port bit2 or address/data bus bit2. Input/output port pin, parallel slave port bit3 or address/data bus bit3. Input/output port pin, parallel slave port bit4 or address/data bus bit4. Input/output port pin, parallel slave port bit5 or address/data bus bit5. Input/output port pin, parallel slave port bit6 or address/data bus bit6. Input/output port pin, parallel slave port bit7 or address/data bus bit7.
ST/TTL(1) ST/TTL(1) ST/TTL(1) ST/TTL ST/TTL
(1)
ST/TTL(1)
(1)
Legend: ST = Schmitt Trigger input, TTL = TTL input Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in System Bus or Parallel Slave Port mode.
TABLE 10-8:
Name PORTD LATD TRISD PSPCON MEMCON
SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Bit 6 RD6 Bit 5 RD5 Bit 4 RD4 Bit 3 RD3 Bit 2 RD2 Bit 1 RD1 Bit 0 RD0 Value on POR, BOR xxxx xxxx xxxx xxxx 1111 1111 -- -- -- -- -- WM1 -- WM0 0000 ---0-00 --00 Value on all other RESETS uuuu uuuu uuuu uuuu 1111 1111 0000 ---0-00 --00
Bit 7 RD7
LATD Data Output Register PORTD Data Direction Register IBF EBDIS OBF -- IBOV WAIT1 PSPMODE WAIT0
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PORTD.
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PIC18FXX20
10.5 PORTE, TRISE and LATE Registers
Note: For PIC18F8X20 (80-pin) devices operating in Extended Microcontroller mode, PORTE defaults to the system bus on Power-on Reset.
PORTE is an 8-bit wide, bi-directional port. The corresponding data direction register is TRISE. Setting a TRISE bit (= 1) will make the corresponding PORTE pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISE bit (= 0) will make the corresponding PORTE pin an output (i.e., put the contents of the output latch on the selected pin). Read-modify-write operations on the LATE register, read and write the latched output value for PORTE. PORTE is an 8-bit port with Schmitt Trigger input buffers. Each pin is individually configurable as an input or output. PORTE is multiplexed with the CCP module (Table 10-9). On PIC18F8X20 devices, PORTE is also multiplexed with the system bus as the external memory interface; the I/O bus is available only when the system bus is disabled, by setting the EBDIS bit in the MEMCON register (MEMCON<7>). If the device is configured in Microprocessor or Extended Microcontroller mode, then the PORTE<7:0> becomes the high byte of the address/data bus for the external program memory interface. In Microcontroller mode, the PORTE<2:0> pins become the control inputs for the Parallel Slave Port when bit PSPMODE (PSPCON<4>) is set. (Refer to Section 4.1.1 for more information on Program Memory modes.) When the Parallel Slave Port is active, three PORTE pins (RE0/RD/AD8, RE1/WR/AD9, and RE2/CS/AD10) function as its control inputs. This automatically occurs when the PSPMODE bit (PSPCON<4>) is set. Users must also make certain that bits TRISE<2:0> are set to configure the pins as digital inputs, and the ADCON1 register is configured for digital I/O. The PORTE PSP control functions are summarized in Table 10-9. Pin RE7 can be configured as the alternate peripheral pin for CCP module 2, when the device is operating in Microcontroller mode. This is done by clearing the configuration bit CCP2MX in configuration register, CONFIG3H (CONFIG3H<0>).
EXAMPLE 10-5:
CLRF PORTE ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTE
Initialize PORTE by clearing output data latches Alternate method to clear output data latches Value used to initialize data direction Set RE1:RE0 as inputs RE7:RE2 as outputs
CLRF
LATE
MOVLW
0x03
MOVWF
TRISE
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PIC18FXX20
FIGURE 10-11: PORTE BLOCK DIAGRAM IN I/O MODE
Peripheral Out Select Peripheral Data Out RD LATE Data Bus WR LATE or WR PORTE D CK Q Q N TRIS Override VSS Pin RE0 RE1 Schmitt Trigger Q D EN RD PORTE Peripheral Data In Note 1: I/O pins have diode protection to VDD and VSS. RE2 RE3 RE4 RE5 RE6 RE7 TRIS OVERRIDE Override Yes Yes Yes Yes Yes Yes Yes Yes Peripheral External Bus External Bus External Bus External Bus External Bus External Bus External Bus External Bus 0 1 VDD P I/O pin(1)
Data Latch D WR TRISE CK Q Q
TRIS Latch RD TRISE Peripheral Enable
FIGURE 10-12:
PORTE BLOCK DIAGRAM IN SYSTEM BUS MODE
Q D EN EN RD PORTE RD LATE Data Bus WR LATE or PORTE D CK Data Latch D WR TRISE CK TRIS Latch RD TRISE Q TTL Input Buffer Q Port Data 0 1 I/O pin(1)
Bus Enable System Bus Data/TRIS Out Control Drive Bus Instruction Register Instruction Read Note 1: I/O pins have protection diodes to VDD and VSS.
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TABLE 10-9:
Name RE0/RD/AD8
PORTE FUNCTIONS
Bit# bit0 Buffer Type ST/TTL(1) Function
Input/output port pin, Read control for parallel slave port, or address/data bit 8 For RD (PSP Control mode): 1 = Not a read operation 0 = Read operation, reads PORTD register (if chip selected) bit1 ST/TTL(1) Input/output port pin, Write control for parallel slave port, or RE1/WR/AD9 address/data bit 9 For WR (PSP Control mode): 1 = Not a write operation 0 = Write operation, writes PORTD register (if chip selected) bit2 ST/TTL(1) Input/output port pin, Chip Select control for parallel slave port, or RE2/CS/AD10 address/data bit 10 For CS (PSP Control mode): 1 = Device is not selected 0 = Device is selected Input/output port pin or address/data bit 11. RE3/AD11 bit3 ST/TTL(1) RE4/AD12 bit4 ST/TTL(1) Input/output port pin or address/data bit 12. (1) RE5/AD13 bit5 ST/TTL Input/output port pin or address/data bit 13. RE6/AD14 bit6 ST/TTL(1) Input/output port pin or address/data bit 14. RE7/CCP2/AD15 bit7 ST/TTL(1) Input/output port pin, Capture2 input/ Compare2 output/PWM output (PIC18F8X20 devices in Microcontroller mode only), or address/data bit 15. Legend: ST = Schmitt Trigger input, TTL = TTL input Note 1: Input buffers are Schmitt Triggers when in I/O or CCP mode, and TTL buffers when in System Bus or PSP Control mode.
TABLE 10-10: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
Name TRISE PORTE LATE MEMCON PSPCON Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on: POR, BOR
1111 1111 xxxx xxxx xxxx xxxx
Value on all other RESETS
1111 1111 uuuu uuuu uuuu uuuu 0000 --00 0000 ----
PORTE Data Direction Control Register Read PORTE pin/Write PORTE Data Latch Read PORTE Data Latch/Write PORTE Data Latch EBDIS IBF -- OBF WAIT1 IBOV WAIT0 PSPMODE -- -- -- -- WM1 -- WM0 --
0-00 --00 0000 ----
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTE.
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PIC18FXX20
10.6 PORTF, LATF, and TRISF Registers
EXAMPLE 10-6:
CLRF PORTF
INITIALIZING PORTF
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Initialize PORTF by clearing output data latches Alternate method to clear output data latches Turn off comparators Set PORTF as digital I/O Value used to initialize data direction Set RF3:RF0 as inputs RF5:RF4 as outputs RF7:RF6 as inputs
PORTF is an 8-bit wide, bi-directional port. The corresponding Data Direction register is TRISF. Setting a TRISF bit (= 1) will make the corresponding PORTF pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISF bit (= 0) will make the corresponding PORTF pin an output (i.e., put the contents of the output latch on the selected pin). Read-modify-write operations on the LATF register, read and write the latched output value for PORTF. PORTF is multiplexed with several analog peripheral functions, including the A/D converter inputs and comparator inputs, outputs, and voltage reference. Note 1: On a Power-on Reset, the RF6:RF0 pins are configured as inputs and read as '0'. 2: To configure PORTF as digital I/O, turn off comparators and set ADCON1 value.
CLRF
LATF
MOVLW MOVWF MOVLW MOVWF MOVLW
0x07 CMCON 0x0F ADCON1 0xCF
MOVWF
TRISF
FIGURE 10-13:
PORTF RF1/AN6/C2OUT, RF2/AN5/C1OUT BLOCK DIAGRAM
PORT/Comparator Select Comparator Data Out 0 1 VDD P
RD LATF Data Bus WR LATF or WR PORTF D CK Q Q
I/O pin N VSS Analog Input Mode Schmitt Trigger Q D EN
Data Latch D Q Q
WR TRISF
CK
TRIS Latch
RD TRISF
RD PORTF To A/D Converter
Note 1: I/O pins have diode protection to VDD and VSS.
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FIGURE 10-14: RF6:RF3 AND RF0 PINS BLOCK DIAGRAM FIGURE 10-15: RF7 PIN BLOCK DIAGRAM
RD LATF Data Bus WR LATF or WR PORTF
RD LATF Data Bus D Q VDD CK Q P N I/O pin WR TRISF VSS Analog Input Mode CK TRIS Latch WR LATF or WR PORTF
D CK
Q I/O pin
Data Latch D Q Schmitt Trigger Input Buffer
Data Latch D WR TRISF Q
CK
Q
TRIS Latch
TTL Input Buffer
RD TRISF RD TRISF Q D EN EN EN RD PORTF SS Input To A/D Converter or Comparator Input Note 1: I/O pins have diode protection to VDD and VSS. Note: I/O pins have diode protection to VDD and VSS. RD PORTF ST Input Buffer
Q
D
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TABLE 10-11: PORTF FUNCTIONS
Name RF0/AN5 RF1/AN6/C2OUT RF2/AN7/C1OUT RF3/AN8 RF4/AN9 RF5/AN10/ CVREF RF6/AN11 RF7/SS Bit# bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 Buffer Type ST ST ST ST ST ST ST ST/TTL Function Input/output port pin or analog input. Input/output port pin, analog input or comparator 2 output. Input/output port pin, analog input or comparator 1 output. Input/output port pin or analog input/comparator input. Input/output port pin or analog input/comparator input. Input/output port pin, analog input/comparator input, or comparator reference output. Input/output port pin or analog input/comparator input. Input/output port pin or Slave Select pin for Synchronous Serial Port.
Legend: ST = Schmitt Trigger input, TTL = TTL input
TABLE 10-12: SUMMARY OF REGISTERS ASSOCIATED WITH PORTF
Name TRISF PORTF LATF ADCON1 CMCON Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on: POR, BOR 1111 1111 xxxx xxxx 0000 0000 --00 0000 0000 0000 0000 0000 CM1 CVR1 CM0 CVR0 Value on all other RESETS 1111 1111 uuuu uuuu uuuu uuuu --00 0000 0000 0000 0000 0000
PORTF Data Direction Control Register Read PORTF pin/Write PORTF Data Latch Read PORTF Data Latch/Write PORTF Data Latch -- C2OUT -- C1OUT CVROE VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 C2INV C1INV CIS CVR3 CM2 CVR2 CVRR CVRSS
CVRCON CVREN
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTF.
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10.7 PORTG, TRISG and LATG Registers
make a pin an input. The user should refer to the corresponding peripheral section for the correct TRIS bit settings. Note: On a Power-on Reset, these pins are configured as digital inputs.
PORTG is a 5-bit wide, bi-directional port. The corresponding data direction register is TRISG. Setting a TRISG bit (= 1) will make the corresponding PORTG pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISG bit (= 0) will make the corresponding PORTC pin an output (i.e., put the contents of the output latch on the selected pin). The Data Latch register (LATG) is also memory mapped. Read-modify-write operations on the LATG register, read and write the latched output value for PORTG. PORTG is multiplexed with both CCP and USART functions (Table 10-13). PORTG pins have Schmitt Trigger input buffers. When enabling peripheral functions, care should be taken in defining TRIS bits for each PORTG pin. Some peripherals override the TRIS bit to make a pin an output, while other peripherals override the TRIS bit to
The pin override value is not loaded into the TRIS register. This allows read-modify-write of the TRIS register, without concern due to peripheral overrides.
EXAMPLE 10-7:
CLRF PORTG ; ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTG
Initialize PORTG by clearing output data latches Alternate method to clear output data latches Value used to initialize data direction Set RG1:RG0 as outputs RG2 as input RG4:RG3 as inputs
CLRF
LATG
MOVLW
0x04
MOVWF
TRISG
FIGURE 10-16:
PORTG BLOCK DIAGRAM (PERIPHERAL OUTPUT OVERRIDE)
PORTG/Peripheral Out Select Peripheral Data Out 0 1
D CK Q Q
VDD P
RD LATG Data Bus WR LATG or WR PORTG
I/O pin(1) N TRIS Override Logic VSS
Data Latch D Q Q
WR TRISG
CK
TRIS Latch RD TRISG Peripheral Output Enable(2)
Schmitt Trigger
Q D EN
TRIS OVERRIDE Pin RG0 RG1 RG2 Override Yes Yes Yes Peripheral CCP3 I/O USART1 Async Xmit, Sync Clock USART1 Async Rcv, Sync Data Out CCP4 I/O CCP5 I/O
RD PORTG Peripheral Data In
Note 1: I/O pins have diode protection to VDD and VSS. 2: Peripheral Output Enable is only active if Peripheral Select is active.
RG3 RG4
Yes Yes
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TABLE 10-13: PORTG FUNCTIONS
Name RG0/CCP3 RG1/TX2/CK2 RG2/RX2/DT2 RG3/CCP4 RG4/CCP5 Bit# bit0 bit1 bit2 bit3 bit4 Buffer Type ST ST ST ST ST Function Input/output port pin or Capture3 input/Compare3 output/ PWM3 output. Input/output port pin, Addressable USART2 Asynchronous Transmit, or Addressable USART2 Synchronous Clock. Input/output port pin, Addressable USART2 Asynchronous Receive, or Addressable USART2 Synchronous Data. Input/output port pin or Capture4 input/Compare4 output/ PWM4 output. Input/output port pin or Capture5 input/Compare5 output/ PWM5 output.
Legend: ST = Schmitt Trigger input
TABLE 10-14: SUMMARY OF REGISTERS ASSOCIATED WITH PORTG
Name PORTG LATG TRISG Bit 7 -- -- -- Bit 6 -- -- -- Bit 5 -- -- -- Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR ---x xxxx ---x xxxx ---1 1111 Value on all other RESETS ---u uuuu ---u uuuu ---1 1111
Read PORTF pin/Write PORTF Data Latch LATG Data Output Register Data Direction Control Register for PORTG
Legend: x = unknown, u = unchanged
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PIC18FXX20
10.8
Note:
PORTH, LATH, and TRISH Registers
PORTH is available only on PIC18F8X20 devices.
FIGURE 10-17:
RH3:RH0 PINS BLOCK DIAGRAM IN I/O MODE
RD LATH Data Bus WR LATH or PORTH
PORTH is an 8-bit wide, bi-directional I/O port. The corresponding data direction register is TRISH. Setting a TRISH bit (= 1) will make the corresponding PORTH pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISH bit (= 0) will make the corresponding PORTH pin an output (i.e., put the contents of the output latch on the selected pin). Read-modify-write operations on the LATH register, read and write the latched output value for PORTH. Pins RH7:RH4 are multiplexed with analog inputs AN15:AN12. Pins RH3:RH0 are multiplexed with the system bus as the external memory interface; they are the high order address bits, A19:A16. By default, pins RH7:RH4 are enabled as A/D inputs and pins RH3:RH0 are enabled as the system address bus. Register ADCON1 configures RH7:RH4 as I/O or A/D inputs. Register MEMCON configures RH3:RH0 as I/O or system bus pins. Note 1: On Power-on Reset, PORTH pins RH7:RH4 default to A/D inputs and read as `0'. 2: On Power-on Reset, PORTH pins RH3:RH0 default to system bus signals.
D CK
Q
I/O pin(1) Data Latch
D Q
WR TRISH
CK
TRIS Latch RD TRISH
Schmitt Trigger Input Buffer
Q
D EN EN
RD PORTH Note 1: I/O pins have diode protection to VDD and VSS.
FIGURE 10-18:
RH7:RH4 PINS BLOCK DIAGRAM IN I/O MODE
EXAMPLE 10-8:
CLRF PORTH
INITIALIZING PORTH
; ; ; ; ; ; ; ; ; ; ; ; ; ; Initialize PORTH by clearing output data latches Alternate method to clear output data latches
RD LATH Data Bus WR LATH or PORTH
D CK
Q
I/O pin(1) Data Latch
D Q
CLRF
LATH
MOVLW MOVWF MOVLW
0Fh ADCON1 0CFh
MOVWF
TRISH
Value used to initialize data direction Set RH3:RH0 as inputs RH5:RH4 as outputs RH7:RH6 as inputs
WR TRISH
CK
TRIS Latch RD TRISH
Schmitt Trigger Input Buffer
Q
D EN EN
RD PORTH To A/D Converter Note 1: I/O pins have diode protection to VDD and VSS.
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FIGURE 10-19: RH3:RH0 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
Q D EN EN
RD PORTH
RD LATD Data Bus WR LATH or PORTH Port I/O pin(1)
0
D CK
Q
Data 1 Data Latch
D Q
WR TRISH
CK
TRIS Latch RD TRISH External Enable System Bus Control Address Out Drive System To Instruction Register Instruction Read Note 1: I/O pins have diode protection to VDD and VSS.
TTL Input Buffer
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PIC18FXX20
TABLE 10-15: PORTH FUNCTIONS
Name RH0/A16 RH1/A17 RH2/A18 RH3/A19 RH4/AN12 RH5/AN13 RH6/AN14 RH7/AN15 Bit# bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 Buffer Type ST/TTL(1) ST/TTL ST/TTL ST ST ST
(1)
Function Input/output port pin or address bit 16 for external memory interface. Input/output port pin or address bit 17 for external memory interface. Input/output port pin or address bit 18 for external memory interface. Input/output port pin or address bit 19 for external memory interface. Input/output port pin or analog input channel 12. Input/output port pin or analog input channel 13. Input/output port pin or analog input channel 14.
ST/TTL(1)
(1)
Input/output port pin or analog input channel 15. ST Legend: ST = Schmitt Trigger input, TTL = TTL input Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in System Bus or Parallel Slave Port mode.
TABLE 10-16: SUMMARY OF REGISTERS ASSOCIATED WITH PORTH
Name TRISH PORTH LATH ADCON1 MEMCON Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on: POR, BOR
1111 1111 xxxx xxxx xxxx xxxx --00 0000 0-00 --00
Value on all other RESETS
1111 1111 uuuu uuuu uuuu uuuu --00 0000 0-00 --00
PORTH Data Direction Control Register Read PORTH pin/Write PORTH Data Latch Read PORTH Data Latch/Write PORTH Data Latch -- EBDIS -- -- VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 WAIT1 WAIT0 -- -- WM1 WM0
Legend: x = unknown, u = unchanged, - = unimplemented. Shaded cells are not used by PORTH.
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PIC18FXX20
10.9
Note:
PORTJ, TRISJ and LATJ Registers
PORTJ is available only on PIC18F8X20 devices.
FIGURE 10-20:
PORTJ BLOCK DIAGRAM IN I/O MODE
RD LATJ Data Bus WR LATJ or PORTJ
PORTJ is an 8-bit wide, bi-directional port. The corresponding Data Direction register is TRISJ. Setting a TRISJ bit (= 1) will make the corresponding PORTJ pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISJ bit (= 0) will make the corresponding PORTJ pin an output (i.e., put the contents of the output latch on the selected pin). The Data Latch register (LATJ) is also memory mapped. Read-modify-write operations on the LATJ register, read and write the latched output value for PORTJ. PORTJ is multiplexed with the system bus as the external memory interface; I/O port functions are only available when the system bus is disabled. When operating as the external memory interface, PORTJ provides the control signal to external memory devices. The RJ5 pin is not multiplexed with any system bus functions. When enabling peripheral functions, care should be taken in defining TRIS bits for each PORTJ pin. Some peripherals override the TRIS bit to make a pin an output, while other peripherals override the TRIS bit to make a pin an input. The user should refer to the corresponding peripheral section for the correct TRIS bit settings. Note: On a Power-on Reset, these pins are configured as digital inputs.
D CK
Q
I/O pin(1) Data Latch
D Q
WR TRISJ
CK
TRIS Latch RD TRISJ
Schmitt Trigger Input Buffer
Q
D EN EN
RD PORTJ Note 1: I/O pins have diode protection to VDD and VSS.
The pin override value is not loaded into the TRIS register. This allows read-modify-write of the TRIS register, without concern due to peripheral overrides.
EXAMPLE 10-9:
CLRF PORTJ ; ; ; ; ; ; ; ; ; ; ; ;
INITIALIZING PORTJ
Initialize PORTG by clearing output data latches Alternate method to clear output data latches Value used to initialize data direction Set RJ3:RJ0 as inputs RJ5:RJ4 as output RJ7:RJ6 as inputs
CLRF
LATJ
MOVLW 0xCF
MOVWF TRISJ
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FIGURE 10-21: RJ4:RJ0 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
Q D EN EN
RD PORTJ
RD LATJ Data Bus WR LATJ or PORTJ Port Data
CK
I/O pin(1)
0 1
D
Q
Data Latch
D Q
WR TRISJ
CK
TRIS Latch RD TRISJ Control Out System Bus Control External Enable Drive System Note 1: I/O pins have diode protection to VDD and VSS.
FIGURE 10-22:
RJ7:RJ6 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
Q D EN EN
RD PORTJ
RD LATJ Data Bus WR LATJ or PORTJ
D CK Q
Port 0 Data 1
I/O pin(1)
Data Latch
D Q
WR TRISJ
CK
TRIS Latch RD TRISJ UB/LB Out System Bus Control WM = 01 Drive System
Note 1: I/O pins have diode protection to VDD and VSS.
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TABLE 10-17: PORTJ FUNCTIONS
Name RJ0/ALE RJ1/OE RJ2/WRL RJ3/WRH RJ4/BA0 RJ5/CE RJ6/LB RJ7/UB Bit# bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 Buffer Type ST ST ST ST ST ST ST ST Function Input/output port pin or Address Latch Enable control for external memory interface. Input/output port pin or Output Enable control for external memory interface. Input/output port pin or Write Low Byte control for external memory interface. Input/output port pin or Write High Byte control for external memory interface. Input/output port pin or Byte Address 0 control for external memory interface. Input/output port pin or Chip Enable control for external memory interface. Input/output port pin or Lower Byte Select control for external memory interface. Input/output port pin or Upper Byte Select control for external memory interface.
Legend: ST = Schmitt Trigger input
TABLE 10-18: SUMMARY OF REGISTERS ASSOCIATED WITH PORTJ
Name PORTJ LATJ TRISJ Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR xxxx xxxx xxxx xxxx 1111 1111 Value on all other RESETS uuuu uuuu uuuu uuuu 1111 1111
Read PORTJ pin/Write PORTJ Data Latch LATJ Data Output Register Data Direction Control Register for PORTJ
Legend: x = unknown, u = unchanged
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10.10 Parallel Slave Port
PORTD also operates as an 8-bit wide Parallel Slave Port, or microprocessor port, when control bit PSPMODE (PSPCON<4>) is set. It is asynchronously readable and writable by the external world through RD control input pin, RE0/RD/AD8 and WR control input pin, RE1/WR/AD9. Note: For PIC18F8X20 devices, the Parallel Slave Port is available only in Microcontroller mode.
FIGURE 10-23:
PORTD AND PORTE BLOCK DIAGRAM (PARALLEL SLAVE PORT)
Data Bus
D CK
Q
WR LATD or PORTD
RDx Pin TTL
Data Latch Q D EN EN TRIS Latch
The PSP can directly interface to an 8-bit microprocessor data bus. The external microprocessor can read or write the PORTD latch as an 8-bit latch. Setting bit PSPMODE enables port pin RE0/RD/AD8 to be the RD input, RE1/WR/AD9 to be the WR input and RE2/CS/AD10 to be the CS (chip select) input. For this functionality, the corresponding data direction bits of the TRISE register (TRISE<2:0>) must be configured as inputs (set). The A/D port configuration bits PCFG2:PCFG0 (ADCON1<2:0>) must be set, which will configure pins RE2:RE0 as digital I/O. A write to the PSP occurs when both the CS and WR lines are first detected low. A read from the PSP occurs when both the CS and RD lines are first detected low. The PORTE I/O pins become control inputs for the microprocessor port when bit PSPMODE (PSPCON<4>) is set. In this mode, the user must make sure that the TRISE<2:0> bits are set (pins are configured as digital inputs), and the ADCON1 is configured for digital I/O. In this mode, the input buffers are TTL.
RD PORTD
RD LATD
One bit of PORTD Set Interrupt Flag PSPIF (PIR1<7>)
Read
TTL
RD CS WR
Chip Select TTL Write TTL
Note: I/O pin has protection diodes to VDD and VSS.
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REGISTER 10-1: PSPCON REGISTER
R-0 IBF bit 7 bit 7 IBF: Input Buffer Full Status bit 1 = A word has been received and is waiting to be read by the CPU 0 = No word has been received OBF: Output Buffer Full Status bit 1 = The output buffer still holds a previously written word 0 = The output buffer has been read IBOV: Input Buffer Overflow Detect bit 1 = A write occurred when a previously input word has not been read (must be cleared in software) 0 = No overflow occurred PSPMODE: Parallel Slave Port Mode Select bit 1 = Parallel Slave Port mode 0 = General Purpose I/O mode Unimplemented: Read as `0' Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R-0 OBF R/W-0 IBOV R/W-0 PSPMODE U-0 -- U-0 -- U-0 -- U-0 -- bit 0
bit 6
bit 5
bit 4
bit 3-0
FIGURE 10-24:
PARALLEL SLAVE PORT WRITE WAVEFORMS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
CS WR RD PORTD<7:0> IBF OBF PSPIF
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FIGURE 10-25: PARALLEL SLAVE PORT READ WAVEFORMS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
CS WR RD PORTD<7:0> IBF OBF PSPIF
TABLE 10-19: REGISTERS ASSOCIATED WITH PARALLEL SLAVE PORT
Name PORTD LATD TRISD PORTE LATE TRISE PSPCON INTCON PIR1 PIE1 IPR1 Note 1: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR xxxx xxxx xxxx xxxx 1111 1111 -- -- -- PSPMODE INT0IE TXIF TXIE TXIP -- -- -- -- RBIE SSPIF SSPIE SSPIP Read PORTE pin/ Write PORTE Data Latch LATE Data Output bits PORTE Data Direction bits -- TMR0IF CCP1IF CCP1IE CCP1IP -- INT0IF TMR2IF TMR2IE TMR2IP -- RBIF TMR1IF TMR1IE TMR1IP 0000 0000 xxxx xxxx 1111 1111 0000 ---0000 0000 0000 0000 0000 0000 0111 1111 Value on all other RESETS uuuu uuuu uuuu uuuu 1111 1111 0000 0000 uuuu uuuu 1111 1111 0000 ---0000 0000 0000 0000 0000 0000 0111 1111
Port Data Latch when written; Port pins when read LATD Data Output bits PORTD Data Direction bits -- -- -- IBF GIE/ GIEH PSPIF(1) PSPIE(1) PSPIP(1) -- -- -- OBF PEIE/ GIEL ADIF ADIE ADIP -- -- -- IBOV TMR0IF RCIF RCIE RCIP
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Parallel Slave Port. Enabled only in Microcontroller mode for PIC18F8X20 devices.
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11.0 TIMER0 MODULE
The Timer0 module has the following features: * Software selectable as an 8-bit or 16-bit timer/counter * Readable and writable * Dedicated 8-bit software programmable prescaler * Clock source selectable to be external or internal * Interrupt-on-overflow from FFh to 00h in 8-bit mode and FFFFh to 0000h in 16-bit mode * Edge select for external clock Figure 11-1 shows a simplified block diagram of the Timer0 module in 8-bit mode and Figure 11-2 shows a simplified block diagram of the Timer0 module in 16-bit mode. The T0CON register (Register 11-1) is a readable and writable register that controls all the aspects of Timer0, including the prescale selection.
REGISTER 11-1:
T0CON: TIMER0 CONTROL REGISTER
R/W-1 TMR0ON bit 7 R/W-1 T08BIT R/W-1 T0CS R/W-1 T0SE R/W-1 PSA R/W-1 T0PS2 R/W-1 T0PS1 R/W-1 T0PS0 bit 0
bit 7
TMR0ON: Timer0 On/Off Control bit 1 = Enables Timer0 0 = Stops Timer0 T08BIT: Timer0 8-bit/16-bit Control bit 1 = Timer0 is configured as an 8-bit timer/counter 0 = Timer0 is configured as a 16-bit timer/counter T0CS: Timer0 Clock Source Select bit 1 = Transition on T0CKI pin 0 = Internal instruction cycle clock (CLKO) T0SE: Timer0 Source Edge Select bit 1 = Increment on high-to-low transition on T0CKI pin 0 = Increment on low-to-high transition on T0CKI pin PSA: Timer0 Prescaler Assignment bit 1 = TImer0 prescaler is NOT assigned. Timer0 clock input bypasses prescaler. 0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output. T0PS2:T0PS0: Timer0 Prescaler Select bits 111 = 1:256 prescale value 110 = 1:128 prescale value 101 = 1:64 prescale value 100 = 1:32 prescale value 011 = 1:16 prescale value 010 = 1:8 prescale value 001 = 1:4 prescale value 000 = 1:2 prescale value Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6
bit 5
bit 4
bit 3
bit 2-0
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FIGURE 11-1: TIMER0 BLOCK DIAGRAM IN 8-BIT MODE
Data Bus FOSC/4 0 0 1 RA4/T0CKI pin T0SE Programmable Prescaler 1 Sync with Internal Clocks (2 TCY delay) PSA Set Interrupt Flag bit TMR0IF on Overflow 8 TMR0
3
T0PS2, T0PS1, T0PS0 T0CS
Note:
Upon RESET, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
FIGURE 11-2:
FOSC/4
TIMER0 BLOCK DIAGRAM IN 16-BIT MODE
0 0 1 Sync with Internal Clocks (2 TCY delay) TMR0L TMR0 High Byte 8 Set Interrupt Flag bit TMR0IF on Overflow
T0CKI pin T0SE
Programmable Prescaler 3
1
PSA T0PS2, T0PS1, T0PS0 T0CS 8 8 TMR0H 8
Read TMR0L Write TMR0L
Data Bus<7:0> Note: Upon RESET, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
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11.1 Timer0 Operation
11.2.1
Timer0 can operate as a timer or as a counter. Timer mode is selected by clearing the T0CS bit. In Timer mode, the Timer0 module will increment every instruction cycle (without prescaler). If the TMR0 register is written, the increment is inhibited for the following two instruction cycles. The user can work around this by writing an adjusted value to the TMR0 register. Counter mode is selected by setting the T0CS bit. In Counter mode, Timer0 will increment, either on every rising or falling edge of pin RA4/T0CKI. The incrementing edge is determined by the Timer0 Source Edge Select bit (T0SE). Clearing the T0SE bit selects the rising edge. Restrictions on the external clock input are discussed below. When an external clock input is used for Timer0, it must meet certain requirements. The requirements ensure the external clock can be synchronized with the internal phase clock (TOSC). Also, there is a delay in the actual incrementing of Timer0 after synchronization.
SWITCHING PRESCALER ASSIGNMENT
The prescaler assignment is fully under software control, (i.e., it can be changed "on-the-fly" during program execution).
11.3
Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0 register overflows from FFh to 00h in 8-bit mode, or FFFFh to 0000h in 16-bit mode. This overflow sets the TMR0IF bit. The interrupt can be masked by clearing the TMR0IE bit. The TMR0IE bit must be cleared in software by the Timer0 module Interrupt Service Routine, before re-enabling this interrupt. The TMR0 interrupt cannot awaken the processor from SLEEP, since the timer is shut-off during SLEEP.
11.4
16-Bit Mode Timer Reads and Writes
11.2
Prescaler
An 8-bit counter is available as a prescaler for the Timer0 module. The prescaler is not readable or writable. The PSA and T0PS2:T0PS0 bits determine the prescaler assignment and prescale ratio. Clearing bit PSA will assign the prescaler to the Timer0 module. When the prescaler is assigned to the Timer0 module, prescale values of 1:2, 1:4,..., 1:256 are selectable. When assigned to the Timer0 module, all instructions writing to the TMR0 register (e.g., CLRF TMR0, MOVWF TMR0, BSF TMR0, x....etc.) will clear the prescaler count. Note: Writing to TMR0 when the prescaler is assigned to Timer0, will clear the prescaler count, but will not change the prescaler assignment.
TMR0H is not the high byte of the timer/counter in 16-bit mode, but is actually a buffered version of the high byte of Timer0 (refer to Figure 11-2). The high byte of the Timer0 counter/timer is not directly readable nor writable. TMR0H is updated with the contents of the high byte of Timer0 during a read of TMR0L. This provides the ability to read all 16 bits of Timer0 without having to verify that the read of the high and low byte were valid, due to a rollover between successive reads of the high and low byte. A write to the high byte of Timer0 must also take place through the TMR0H buffer register. Timer0 high byte is updated with the contents of TMR0H when a write occurs to TMR0L. This allows all 16 bits of Timer0 to be updated at once.
TABLE 11-1:
Name TMR0L TMR0H INTCON T0CON TRISA
REGISTERS ASSOCIATED WITH TIMER0
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other RESETS
Bit 7
Timer0 Module Low Byte Register Timer0 Module High Byte Register GIE/GIEH PEIE/GIEL TMR0IE INT0IE TMR0ON -- T08BIT T0CS T0SE PORTA Data Direction Register RBIE PSA TMR0IF INT0IF T0PS2 T0PS1 RBIF
xxxx xxxx uuuu uuuu 0000 0000 0000 0000 0000 0000 0000 0000 T0PS0 1111 1111 1111 1111 -111 1111 -111 1111
Legend: x = unknown, u = unchanged, - = unimplemented locations, read as '0'. Shaded cells are not used by Timer0.
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NOTES:
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12.0 TIMER1 MODULE
The Timer1 module timer/counter has the following features: * 16-bit timer/counter (two 8-bit registers: TMR1H and TMR1L) * Readable and writable (both registers) * Internal or external clock select * Interrupt-on-overflow from FFFFh to 0000h * RESET from CCP module special event trigger Figure 12-1 is a simplified block diagram of the Timer1 module. Register 12-1 details the Timer1 control register. This register controls the Operating mode of the Timer1 module, and contains the Timer1 oscillator enable bit (T1OSCEN). Timer1 can be enabled or disabled by setting or clearing control bit, TMR1ON (T1CON<0>). Timer1 can also be used to provide Real-Time Clock (RTC) functionality to applications, with only a minimal addition of external components and code overhead.
REGISTER 12-1:
T1CON: TIMER1 CONTROL REGISTER
R/W-0 RD16 bit 7 U-0 -- R/W-0 T1CKPS1 R/W-0 T1CKPS0 R/W-0 T1OSCEN R/W-0 T1SYNC R/W-0 TMR1CS R/W-0 TMR1ON bit 0
bit 7
RD16: 16-bit Read/Write Mode Enable bit 1 = Enables register Read/Write of Timer1 in one 16-bit operation 0 = Enables register Read/Write of Timer1 in two 8-bit operations Unimplemented: Read as '0' T1CKPS1:T1CKPS0: Timer1 Input Clock Prescale Select bits 11 = 1:8 Prescale value 10 = 1:4 Prescale value 01 = 1:2 Prescale value 00 = 1:1 Prescale value T1OSCEN: Timer1 Oscillator Enable bit 1 = Timer1 Oscillator is enabled 0 = Timer1 Oscillator is shut-off The oscillator inverter and feedback resistor are turned off to eliminate power drain. T1SYNC: Timer1 External Clock Input Synchronization Select bit When TMR1CS = 1: 1 = Do not synchronize external clock input 0 = Synchronize external clock input When TMR1CS = 0: This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0. TMR1CS: Timer1 Clock Source Select bit 1 = External clock from pin RC0/T1OSO/T13CKI (on the rising edge) 0 = Internal clock (FOSC/4) TMR1ON: Timer1 On bit 1 = Enables Timer1 0 = Stops Timer1 Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6 bit 5-4
bit 3
bit 2
bit 1
bit 0
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12.1 Timer1 Operation
Timer1 can operate in one of these modes: * As a timer * As a synchronous counter * As an asynchronous counter The Operating mode is determined by the clock select bit, TMR1CS (T1CON<1>). When TMR1CS = 0, Timer1 increments every instruction cycle. When TMR1CS = 1, Timer1 increments on every rising edge of the external clock input, or the Timer1 oscillator, if enabled. When the Timer1 oscillator is enabled (T1OSCEN is set), the RC1/T1OSI and RC0/T1OSO/T13CKI pins become inputs. That is, the TRISC<1:0> value is ignored, and the pins are read as `0'. Timer1 also has an internal "RESET input". This RESET can be generated by the CCP module (Section 16.0).
FIGURE 12-1:
TMR1IF Overflow Interrupt Flag Bit
TIMER1 BLOCK DIAGRAM
CCP Special Event Trigger TMR1 TMR1H CLR TMR1L TMR1ON On/Off 0 1 T1SYNC Prescaler 1, 2, 4, 8 0 2 T1CKPS1:T1CKPS0 TMR1CS SLEEP Input Synchronize det Synchronized Clock Input
T13CKI/T1OSO T1OSI
T1OSC T1OSCEN Enable Oscillator(1) FOSC/4 Internal Clock
1
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
FIGURE 12-2:
TIMER1 BLOCK DIAGRAM: 16-BIT READ/WRITE MODE
8
TMR1H
Data Bus<7:0>
8 Write TMR1L Read TMR1L TMR1IF Overflow Interrupt Flag bit 8 Timer 1 High Byte TMR1
8 CCP Special Event Trigger Synchronized Clock Input
CLR TMR1L TMR1ON On/Off 1 T1OSCEN Enable Oscillator(1) FOSC/4 Internal Clock
0 1 T1SYNC Prescaler 1, 2, 4, 8 0 2 TMR1CS
T1OSC T13CKI/T1OSO
Synchronize det SLEEP Input
T1OSI
T1CKPS1:T1CKPS0 Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
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12.2 Timer1 Oscillator
12.2.1
A crystal oscillator circuit is built-in between pins T1OSI (input) and T1OSO (amplifier output). It is enabled by setting control bit, T1OSCEN (T1CON<3>). The oscillator is a low power oscillator rated up to 200 kHz. It will continue to run during SLEEP. It is primarily intended for a 32 kHz crystal. The circuit for a typical LP oscillator is shown in Figure 12-3. Table 12-1 shows the capacitor selection for the Timer1 oscillator. The user must provide a software time delay to ensure proper start-up of the Timer1 oscillator
LOW POWER TIMER1 OPTION (PIC18FX520 DEVICES ONLY)
The Timer1 oscillator for PIC18FX520 devices incorporates an additional low power feature. When this option is selected, it allows the oscillator to automatically reduce its power consumption when the microcontroller is in SLEEP mode. During normal device operation, the oscillator draws full current. As high noise environments may cause excessive oscillator instability in SLEEP mode, this option is best suited for low noise applications where power conservation is an important design consideration. The low power option is enabled by clearing the T1OSCMX bit (CONFIG3H<1>). By default, the option is disabled, which results in a more-or-less constant current draw for the Timer1 oscillator. Due to the low power nature of the oscillator, it may also be sensitive to rapidly changing signals in close proximity. The oscillator circuit, shown in Figure 12-3, should be located as close as possible to the microcontroller. There should be no circuits passing within the oscillator circuit boundaries other than VSS or VDD. If a high speed circuit must be located near the oscillator (such as the CCP1 pin in output compare or PWM mode, or the primary oscillator using the OSC2 pin), a grounded guard ring around the oscillator circuit, as shown in Figure 12-4, may be helpful when used on a single sided PCB, or in addition to a ground plane.
FIGURE 12-3:
EXTERNAL COMPONENTS FOR THE TIMER1 LP OSCILLATOR
PIC18FXX20
T1OSI XTAL 32.768 kHz T1OSO
C1 33 pF
C2 33 pF Note: See the Notes with Table 12-1 for additional information about capacitor selection.
TABLE 12-1:
CAPACITOR SELECTION FOR THE ALTERNATE OSCILLATOR
Freq 32 kHz C1 TBD(1) C2 TBD(1) 20 PPM
FIGURE 12-4:
Osc Type LP
OSCILLATOR CIRCUIT WITH GROUNDED GUARD RING
VDD VSS OSC1
Crystal to be Tested: 32.768 kHz Epson C-001R32.768K-A
Note 1: Microchip suggests 33 pF as a starting point in validating the oscillator circuit. 2: Higher capacitance increases the stability of the oscillator, but also increases the start-up time. 3: Since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropriate values of external components. 4: Capacitor values are for design guidance only.
OSC2
RC0 RC1
RC2 Note: Not drawn to scale.
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12.3 Timer1 Interrupt 12.6
The TMR1 Register pair (TMR1H:TMR1L) increments from 0000h to FFFFh and rolls over to 0000h. The TMR1 interrupt, if enabled, is generated on overflow, which is latched in interrupt flag bit, TMR1IF (PIR1<0>). This interrupt can be enabled/disabled by setting/clearing TMR1 interrupt enable bit, TMR1IE (PIE1<0>).
Using Timer1 as a Real-Time Clock
12.4
Resetting Timer1 using a CCP Trigger Output
Adding an external LP oscillator to Timer1 (such as the one described in Section 12.2, above) gives users the option to include RTC functionality to their applications. This is accomplished with an inexpensive watch crystal to provide an accurate time-base, and several lines of application code to calculate the time. When operating in SLEEP mode and using a battery or supercapacitor as a power source, it can completely eliminate the need for a separate RTC device and battery backup. The application code routine, RTCisr, shown in Example 12-1, demonstrates a simple method to increment a counter at one-second intervals using an Interrupt Service Routine. Incrementing the TMR1 register pair to overflow, triggers the interrupt and calls the routine, which increments the seconds counter by one; additional counters for minutes and hours are incremented as the previous counter overflow. Since the register pair is 16-bits wide, counting up to overflow the register directly from a 32.768 kHz clock would take 2 seconds. To force the overflow at the required one-second intervals, it is necessary to preload it; the simplest method is to set the MSbit of TMR1H with a BSF instruction. Note that the TMR1L register is never pre-loaded or altered; doing so may introduce cumulative error over many cycles. For this method to be accurate, Timer1 must operate in Asynchronous mode, and the Timer1 Overflow interrupt must be enabled (PIE1<0> = 1), as shown in the routine, RTCinit. The Timer1 oscillator must also be enabled and running at all times.
If the CCP module is configured in Compare mode to generate a "special event trigger" (CCP1M3:CCP1M0 = 1011), this signal will reset Timer1 and start an A/D conversion (if the A/D module is enabled). Note: The special event triggers from the CCP1 module will not set interrupt flag bit TMR1IF (PIR1<0>).
Timer1 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature. If Timer1 is running in Asynchronous Counter mode, this RESET operation may not work. In the event that a write to Timer1 coincides with a special event trigger from CCP1, the write will take precedence. In this mode of operation, the CCPR1H:CCPR1L registers pair effectively becomes the period register for Timer1.
12.5
Timer1 16-Bit Read/Write Mode
Timer1 can be configured for 16-bit reads and writes (see Figure 12-2). When the RD16 control bit (T1CON<7>) is set, the address for TMR1H is mapped to a buffer register for the high byte of Timer1. A read from TMR1L will load the contents of the high byte of Timer1 into the Timer1 high byte buffer. This provides the user with the ability to accurately read all 16-bits of Timer1 without having to determine whether a read of the high byte, followed by a read of the low byte, is valid, due to a rollover between reads. A write to the high byte of Timer1 must also take place through the TMR1H buffer register. Timer1 high byte is updated with the contents of TMR1H when a write occurs to TMR1L. This allows a user to write all 16 bits to both the high and low bytes of Timer1 at once. The high byte of Timer1 is not directly readable or writable in this mode. All reads and writes must take place through the Timer1 high byte buffer register. Writes to TMR1H do not clear the Timer1 prescaler. The prescaler is only cleared on writes to TMR1L.
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EXAMPLE 12-1:
RTCinit movlw movwf clrf movlw movwf clrf clrf movlw movwf bsf return RTCisr bsf bcf incf movlw cpfsgt return clrf incf movlw cpfsgt return clrf incf movlw cpfsgt return movlw movwf return TMR1H,7 PIR1,TMR1IF secs,F .59 secs secs mins,F .59 mins mins hours,F .23 hours .01 hours ; ; ; ; ; ; ; ; ; ; ; ; Preload for 1 sec overflow Clear interrupt flag Increment seconds 60 seconds elapsed? No, done Clear seconds Increment minutes 60 minutes elapsed? No, done clear minutes Increment hours 24 hours elapsed? 0x80 TMR1H TMR1L b'00001111' T1OSC secs mins .12 hours PIE1, TMR1IE ; Preload TMR1 register pair ; for 1 second overflow ; Configure for external clock, ; Asynchronous operation, external oscillator ; Initialize timekeeping registers ;
IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
; Enable Timer1 interrupt
; No, done ; Reset hours to 1 ; Done
TABLE 12-2:
Name INTCON PIR1 PIE1 IPR1 TMR1L TMR1H T1CON Legend: Bit 7
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Bit 6 Bit 5 TMR0IE RCIF RCIE RCIP Bit 4 INT0IE TXIF TXIE TXIP Bit 3 RBIE SSPIF SSPIE SSPIP Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP Bit 1 INT0IF TMR2IF TMR2IE TMR2IP Bit 0 RBIF TMR1IF TMR1IE TMR1IP Value on POR, BOR Value on all other RESETS
GIE/GIEH PEIE/GIEL PSPIF PSPIE PSPIP ADIF ADIE ADIP
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0111 1111 0111 1111 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register Holding Register for the Most Significant Byte of the 16-bit TMR1 Register RD16 --
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 u-uu uuuu
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer1 module.
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13.0
* * * * * * *
TIMER2 MODULE
13.1
Timer2 Operation
The Timer2 module timer has the following features: 8-bit timer (TMR2 register) 8-bit period register (PR2) Readable and writable (both registers) Software programmable prescaler (1:1, 1:4, 1:16) Software programmable postscaler (1:1 to 1:16) Interrupt on TMR2 match of PR2 SSP module optional use of TMR2 output to generate clock shift
Timer2 can be used as the PWM time-base for the PWM mode of the CCP module. The TMR2 register is readable and writable, and is cleared on any device RESET. The input clock (FOSC/4) has a prescale option of 1:1, 1:4 or 1:16, selected by control bits, T2CKPS1:T2CKPS0 (T2CON<1:0>). The match output of TMR2 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a TMR2 interrupt (latched in flag bit, TMR2IF (PIR1<1>)). The prescaler and postscaler counters are cleared when any of the following occurs: * a write to the TMR2 register * a write to the T2CON register * any device RESET (Power-on Reset, MCLR Reset, Watchdog Timer Reset, or Brown-out Reset) TMR2 is not cleared when T2CON is written.
Timer2 has a control register shown in Register 13-1. Timer2 can be shut-off by clearing control bit, TMR2ON (T2CON<2>), to minimize power consumption. Figure 13-1 is a simplified block diagram of the Timer2 module. Register 13-1 shows the Timer2 control register. The prescaler and postscaler selection of Timer2 are controlled by this register.
REGISTER 13-1:
T2CON: TIMER2 CONTROL REGISTER
U-0 -- bit 7 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 bit 0 T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0
bit 7 bit 6-3
Unimplemented: Read as '0' T2OUTPS3:T2OUTPS0: Timer2 Output Postscale Select bits 0000 = 1:1 Postscale 0001 = 1:2 Postscale * * * 1111 = 1:16 Postscale TMR2ON: Timer2 On bit 1 = Timer2 is on 0 = Timer2 is off T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits 00 = Prescaler is 1 01 = Prescaler is 4 1x = Prescaler is 16 Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 2
bit 1-0
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13.2 Timer2 Interrupt 13.3 Output of TMR2
The Timer2 module has an 8-bit period register, PR2. Timer2 increments from 00h until it matches PR2 and then resets to 00h on the next increment cycle. PR2 is a readable and writable register. The PR2 register is initialized to FFh upon RESET. The output of TMR2 (before the postscaler) is fed to the Synchronous Serial Port module, which optionally uses it to generate the shift clock.
FIGURE 13-1:
TIMER2 BLOCK DIAGRAM
TMR2 Output(1) Sets Flag bit TMR2IF
FOSC/4
Prescaler 1:1, 1:4, 1:16 2 T2CKPS1:T2CKPS0
TMR2 Comparator
RESET Postscaler 1:1 to 1:16 4 T2OUTPS3:T2OUTPS0
EQ
PR2
Note 1: TMR2 register output can be software selected by the SSP Module as a baud clock.
TABLE 13-1:
Name Bit 7
REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Bit 6 Bit 5 TMR0IE RCIF RCIE RCIP Bit 4 INT0IE TXIF TXIE TXIP Bit 3 RBIE SSPIF SSPIE SSPIP Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP Bit 1 INT0IF TMR2IF TMR2IE TMR2IP Bit 0 RBIF Value on POR, BOR Value on all other RESETS
INTCON GIE/GIEH PEIE/GIEL PIR1 PIE1 IPR1 TMR2 T2CON PR2 PSPIF PSPIE PSPIP -- ADIF ADIE ADIP
0000 0000 0000 0000
TMR1IF 0000 0000 0000 0000 TMR1IE 0000 0000 0000 0000 TMR1IP 0111 1111 0111 1111 0000 0000 0000 0000 1111 1111 1111 1111
Timer2 Module Register Timer2 Period Register
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer2 module.
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14.0 TIMER3 MODULE
The Timer3 module timer/counter has the following features: * 16-bit timer/counter (two 8-bit registers; TMR3H and TMR3L) * Readable and writable (both registers) * Internal or external clock select * Interrupt-on-overflow from FFFFh to 0000h * RESET from CCP module trigger Figure 14-1 is a simplified block diagram of the Timer3 module. Register 14-1 shows the Timer3 control register. This register controls the Operating mode of the Timer3 module and sets the CCP clock source. Register 12-1 shows the Timer1 control register. This register controls the Operating mode of the Timer1 module, as well as contains the Timer1 oscillator enable bit (T1OSCEN), which can be a clock source for Timer3.
REGISTER 14-1:
T3CON: TIMER3 CONTROL REGISTER
R/W-0 RD16 bit 7 R/W-0 T3CCP2 R/W-0 T3CKPS1 R/W-0 T3CKPS0 R/W-0 T3CCP1 R/W-0 T3SYNC R/W-0 TMR3CS R/W-0 TMR3ON bit 0
bit 7
RD16: 16-bit Read/Write Mode Enable bit 1 = Enables register Read/Write of Timer3 in one 16-bit operation 0 = Enables register Read/Write of Timer3 in two 8-bit operations T3CCP2:T3CCP1: Timer3 and Timer1 to CCPx Enable bits 11 = Timer3 and Timer4 are the clock sources for CCP1 through CCP5 10 = Timer3 and Timer4 are the clock sources for CCP3 through CCP5; Timer1 and Timer2 are the clock sources for CCP1 and CCP2 01 = Timer3 and Timer4 are the clock sources for CCP2 through CCP5; Timer1 and Timer2 are the clock sources for CCP1 00 = Timer1 and Timer2 are the clock sources for CCP1 through CCP5 T3CKPS1:T3CKPS0: Timer3 Input Clock Prescale Select bits 11 = 1:8 Prescale value 10 = 1:4 Prescale value 01 = 1:2 Prescale value 00 = 1:1 Prescale value T3SYNC: Timer3 External Clock Input Synchronization Control bit (Not usable if the system clock comes from Timer1/Timer3.) When TMR3CS = 1: 1 = Do not synchronize external clock input 0 = Synchronize external clock input When TMR3CS = 0: This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0. TMR3CS: Timer3 Clock Source Select bit 1 = External clock input from Timer1 oscillator or T13CKI (on the rising edge after the first falling edge) 0 = Internal clock (FOSC/4) TMR3ON: Timer3 On bit 1 = Enables Timer3 0 = Stops Timer3 Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6,3
bit 5-4
bit 2
bit 1
bit 0
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14.1 Timer3 Operation
Timer3 can operate in one of these modes: * As a timer * As a synchronous counter * As an asynchronous counter The Operating mode is determined by the clock select bit, TMR3CS (T3CON<1>). When TMR3CS = 0, Timer3 increments every instruction cycle. When TMR3CS = 1, Timer3 increments on every rising edge of the Timer1 external clock input or the Timer1 oscillator, if enabled. When the Timer1 oscillator is enabled (T1OSCEN is set), the RC1/T1OSI and RC0/T1OSO/T13CKI pins become inputs. That is, the TRISC<1:0> value is ignored, and the pins are read as `0'. Timer3 also has an internal "RESET input". This RESET can be generated by the CCP module (Section 14.0).
FIGURE 14-1:
TIMER3 BLOCK DIAGRAM
TMR3IF Overflow Interrupt Flag bit TMR3H CCP Special Trigger T3CCPx CLR TMR3L TMR3ON On/Off 0 1 T3SYNC Synchronized Clock Input
T1OSO/ T13CKI
T1OSC
(3)
1 T1OSCEN FOSC/4 Enable Internal Oscillator(1) Clock Prescaler 1, 2, 4, 8 0 2 TMR3CS T3CKPS1:T3CKPS0
Synchronize det SLEEP Input
T1OSI
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
FIGURE 14-2:
TIMER3 BLOCK DIAGRAM CONFIGURED IN 16-BIT READ/WRITE MODE
8 TMR3H 8 8
Data Bus<7:0>
Write TMR3L Read TMR3L Set TMR3IF Flag bit on Overflow 8 Timer3 High Byte TMR3 TMR3L CLR CCP Special Trigger T3CCPx 0 1 TMR3ON On/Off 1 T1OSCEN Enable Oscillator(1) FOSC/4 Internal Clock Prescaler 1, 2, 4, 8 0 2 T3CKPS1:T3CKPS0 TMR3CS SLEEP Input T3SYNC Synchronize det
Synchronized Clock Input
To Timer1 Clock Input T1OSO/ T13CKI T1OSC
T1OSI
Note 1: When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
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14.2 Timer1 Oscillator 14.4
The Timer1 oscillator may be used as the clock source for Timer3. The Timer1 oscillator is enabled by setting the T1OSCEN (T1CON<3>) bit. The oscillator is a low power oscillator rated up to 200 kHz. See Section 12.0 for further details.
Resetting Timer3 Using a CCP Trigger Output
If the CCP module is configured in Compare mode to generate a "special event trigger" (CCP1M3:CCP1M0 = 1011), this signal will reset Timer3. Note: The special event triggers from the CCP module will not set interrupt flag bit, TMR3IF (PIR1<0>).
14.3
Timer3 Interrupt
The TMR3 register pair (TMR3H:TMR3L) increments from 0000h to FFFFh and rolls over to 0000h. The TMR3 interrupt, if enabled, is generated on overflow, which is latched in interrupt flag bit, TMR3IF (PIR2<1>). This interrupt can be enabled/disabled by setting/clearing TMR3 interrupt enable bit, TMR3IE (PIE2<1>).
Timer3 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature. If Timer3 is running in Asynchronous Counter mode, this RESET operation may not work. In the event that a write to Timer3 coincides with a special event trigger from CCP1, the write will take precedence. In this mode of operation, the CCPR1H:CCPR1L registers pair effectively becomes the period register for Timer3.
TABLE 14-1:
Name Bit 7 GIE/ GIEH -- -- --
REGISTERS ASSOCIATED WITH TIMER3 AS A TIMER/COUNTER
Bit 6 PEIE/ GIEL -- -- -- Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other RESETS
INTCON PIR2 PIE2 IPR2 TMR3L TMR3H T1CON T3CON Legend:
TMR0IE -- -- --
INT0IE EEIF EEIE EEIP
RBIE BCLIF BCLIE BCLIP
TMR0IF LVDIF LVDIE LVDIP
INT0IF TMR3IF TMR3IE TMR3IP
RBIF CCP2IF CCP2IE CCP2IP
0000 0000 0000 0000 ---0 0000 ---0 0000 ---0 0000 ---0 0000 ---1 1111 ---1 1111 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu
Holding Register for the Least Significant Byte of the 16-bit TMR3 Register Holding Register for the Most Significant Byte of the 16-bit TMR3 Register RD16 RD16 -- T3CCP2 T1CKPS1 T1CKPS0 T1OSCEN T3CKPS1 T3CKPS0 T3CCP1 T1SYNC T3SYNC
TMR1CS TMR1ON 0-00 0000 u-uu uuuu TMR3CS TMR3ON 0000 0000 uuuu uuuu
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer3 module.
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15.0
* * * * * *
TIMER4 MODULE
15.1
Timer4 Operation
The Timer4 module timer has the following features: 8-bit timer (TMR4 register) 8-bit period register (PR4) Readable and writable (both registers) Software programmable prescaler (1:1, 1:4, 1:16) Software programmable postscaler (1:1 to 1:16) Interrupt on TMR4 match of PR4
Timer4 has a control register shown in Register 15-1. Timer4 can be shut-off by clearing control bit, TMR4ON (T4CON<2>), to minimize power consumption. The prescaler and postscaler selection of Timer4 are also controlled by this register. Figure 15-1 is a simplified block diagram of the Timer4 module.
Timer4 can be used as the PWM time-base for the PWM mode of the CCP module. The TMR4 register is readable and writable, and is cleared on any device RESET. The input clock (FOSC/4) has a prescale option of 1:1, 1:4 or 1:16, selected by control bits T4CKPS1:T4CKPS0 (T4CON<1:0>). The match output of TMR4 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a TMR4 interrupt (latched in flag bit TMR4IF, (PIR3<3>)). The prescaler and postscaler counters are cleared when any of the following occurs: * a write to the TMR4 register * a write to the T4CON register * any device RESET (Power-on Reset, MCLR Reset, Watchdog Timer Reset, or Brown-out Reset) TMR4 is not cleared when T4CON is written.
REGISTER 15-1:
T4CON: TIMER4 CONTROL REGISTER
U-0 -- bit 7 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 T4CKPS0 bit 0 T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1
bit 7 bit 6-3
Unimplemented: Read as '0' T4OUTPS3:T4OUTPS0: Timer4 Output Postscale Select bits 0000 = 1:1 Postscale 0001 = 1:2 Postscale * * * 1111 = 1:16 Postscale TMR4ON: Timer4 On bit 1 = Timer4 is on 0 = Timer4 is off T4CKPS1:T4CKPS0: Timer4 Clock Prescale Select bits 00 = Prescaler is 1 01 = Prescaler is 4 1x = Prescaler is 16 Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 2
bit 1-0
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15.2 Timer4 Interrupt 15.3 Output of TMR4
The Timer4 module has an 8-bit period register, PR4, which is both readable and writable. Timer4 increments from 00h until it matches PR4 and then resets to 00h on the next increment cycle. The PR4 register is initialized to FFh upon RESET. The output of TMR4 (before the postscaler) is used only as a PWM time-base for the CCP modules. It is not used as a baud rate clock for the MSSP, as is the Timer2 output.
FIGURE 15-1:
TIMER4 BLOCK DIAGRAM
TMR4 Output(1) Sets Flag bit TMR4IF
FOSC/4
Prescaler 1:1, 1:4, 1:16 2 T4CKPS1:T4CKPS0
TMR4 Comparator
RESET Postscaler 1:1 to 1:16 4 T4OUTPS3:T4OUTPS0
EQ
PR4
TABLE 15-1:
Name Bit 7
REGISTERS ASSOCIATED WITH TIMER4 AS A TIMER/COUNTER
Bit 6 Bit 5 TMR0IE RC2IP RC2IF RC2IE Bit 4 INT0IE TX2IP TX2IF TX2IE Bit 3 RBIE TMR4IP TMR4IF TMR4IE Bit 2 TMR0IF CCP5IP CCP5IF CCP5IE Bit 1 INT0IF CCP4IP CCP4IF CCP4IE Bit 0 RBIF CCP3IF Value on POR, BOR Value on all other RESETS
INTCON GIE/GIEH PEIE/GIEL IPR3 PIR3 PIE3 TMR4 T4CON PR4 -- -- -- -- -- -- --
0000 0000 0000 0000
CCP3IP --11 1111 --00 0000 --00 0000 --00 0000 CCP3IE --00 0000 --00 0000 0000 0000 0000 0000 1111 1111 1111 1111
Timer4 Module Register Timer4 Period Register
T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 -000 0000 -000 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer4 module.
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16.0 CAPTURE/COMPARE/PWM (CCP) MODULES
For the sake of clarity, CCP module operation in the following sections is described with respect to CCP1. The descriptions can be applied (with the exception of the special event triggers) to any of the modules. Note: Throughout this section, references to register and bit names that may be associated with a specific CCP module are referred to generically by the use of `x' or `y' in place of the specific module number. Thus, "CCPxCON" might refer to the control register for CCP1, CCP2, CCP3, CCP4 or CCP5.
The PIC18FXX20 devices all have five CCP (Capture/Compare/PWM) modules. Each module contains a 16-bit register, which can operate as a 16-bit Capture register, a 16-bit Compare register or a Pulse Width Modulation (PWM) Master/Slave Duty Cycle register. Table 16-1 shows the timer resources of the CCP module modes. The operation of all CCP modules are identical, with the exception of the special event trigger present on CCP1 and CCP2.
REGISTER 16-1:
CCPxCON REGISTER
U-0 -- bit 7 U-0 -- R/W-0 DCxB1 R/W-0 DCxB0 R/W-0 CCPxM3 R/W-0 CCPxM2 R/W-0 R/W-0 bit 0 CCPxM1 CCPxM0
bit 7-6 bit 5-4
Unimplemented: Read as '0' DCxB1:DCxB0: PWM Duty Cycle bit 1 and bit 0 for CCP module x Capture mode: Unused Compare mode: Unused PWM mode: These bits are the two LSbits (bit 1 and bit 0) of the 10-bit PWM duty cycle. The eight MSbits (DCx9:DCx2) of the duty cycle are found in CCPRxL. CCPxM3:CCPxM0: CCP Module x Mode Select bits 0000 = Capture/Compare/PWM disabled (resets CCPx module) 0001 = Reserved 0010 = Compare mode, toggle output on match (CCPxIF bit is set) 0011 = Reserved 0100 = Capture mode, every falling edge 0101 = Capture mode, every rising edge 0110 = Capture mode, every 4th rising edge 0111 = Capture mode, every 16th rising edge 1000 = Compare mode, Initialize CCP pin Low; on compare match, force CCP pin High (CCPIF bit is set) 1001 = Compare mode, Initialize CCP pin High; on compare match, force CCP pin Low (CCPIF bit is set) 1010 = Compare mode, Generate software interrupt on compare match (CCPIF bit is set, CCP pin is unaffected) 1011 = Compare mode, trigger special event (CCPIF bit is set): For CCP1 and CCP2: Timer1 or Timer3 is reset on event For all other modules: CCPx pin is unaffected and is configured as an I/O port (same as CCPxM<3:0> = 1010, above) 11xx = PWM mode Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 3-0
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16.1 CCP Module Configuration
TABLE 16-1:
Each Capture/Compare/PWM module is associated with a control register (generically, CCPxCON) and a data register (CCPRx). The data register, in turn, is comprised of two 8-bit registers: CCPRxL (low byte) and CCPRxH (high byte). All registers are both readable and writable.
CCP MODE - TIMER RESOURCE
Timer Resource Timer1 or Timer3 Timer1 or Timer3 Timer2 or Timer4
CCP Mode Capture Compare PWM
16.1.1
CCP MODULES AND TIMER RESOURCES
The CCP modules utilize Timers 1, 2, 3 or 4, depending on the mode selected. Timer1 and Timer3 are available to modules in Capture or Compare modes, while Timer2 and Timer4 are available for modules in PWM mode.
The assignment of a particular timer to a module is determined by the Timer-to-CCP Enable bits in the T3CON register (Register 14-1, page 143). Depending on the configuration selected, up to four timers may be active at once, with modules in the same configuration (Capture/Compare or PWM) sharing timer resources. The possible configurations are shown in Figure 16-1.
FIGURE 16-1:
CCP AND TIMER INTERCONNECT CONFIGURATIONS
T3CCP<2:1> = 01 TMR1 TMR3 T3CCP<2:1> = 10 TMR1 TMR3 T3CCP<2:1> = 11 TMR1 TMR3
T3CCP<2:1> = 00 TMR1 TMR3
CCP1 CCP2 CCP3 CCP4 CCP5
CCP1 CCP2 CCP3 CCP4 CCP5
CCP1 CCP2 CCP3 CCP4 CCP5
CCP1 CCP2 CCP3 CCP4 CCP5
TMR2
TMR4
TMR2
TMR4
TMR2
TMR4
TMR2
TMR4
Timer1 is used for all Capture and Compare operations for all CCP modules. Timer2 is used for PWM operations for all CCP modules. Modules may share either timer resource as a common time-base. Timer3 and Timer4 are not available.
Timer1 and Timer2 are used for Capture and Compare or PWM operations for CCP1 only (depending on selected mode). All other modules use either Timer3 or Timer4. Modules may share either timer resource as a common timebase, if they are in Capture/Compare or PWM modes.
Timer1 and Timer2 are used for Capture and Compare or PWM operations for CCP1 and CCP2 only (depending on the mode selected for each module). Both modules may use a timer as a common time-base if they are both in Capture/Compare or PWM modes. The other modules use either Timer3 or Timer4. Modules may share either timer resource as a common timebase if they are in Capture/Compare or PWM modes.
Timer3 is used for all Capture and Compare operations for all CCP modules. Timer4 is used for PWM operations for all CCP modules. Modules may share either timer resource as a common time-base. Timer1 and Timer2 are not available.
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16.2 Capture Mode
16.2.3 SOFTWARE INTERRUPT
In Capture mode, CCPR1H:CCPR1L captures the 16-bit value of the TMR1 or TMR3 registers when an event occurs on pin RC2/CCP1. An event is defined as one of the following: * * * * every falling edge every rising edge every 4th rising edge every 16th rising edge When the Capture mode is changed, a false capture interrupt may be generated. The user should keep bit CCP1IE (PIE1<2>) clear to avoid false interrupts and should clear the flag bit, CCP1IF, following any such change in Operating mode.
16.2.4
CCP PRESCALER
The event is selected by control bits, CCP1M3:CCP1M0 (CCP1CON<3:0>). When a capture is made, the interrupt request flag bit, CCP1IF (PIR1<2>), is set; it must be cleared in software. If another capture occurs before the value in register CCPR1 is read, the old captured value is overwritten by the new captured value.
There are four prescaler settings, specified by bits CCP1M3:CCP1M0. Whenever the CCP module is turned off or the CCP module is not in Capture mode, the prescaler counter is cleared. This means that any RESET will clear the prescaler counter. Switching from one capture prescaler to another may generate an interrupt. Also, the prescaler counter will not be cleared, therefore, the first capture may be from a non-zero prescaler. Example 16-1 shows the recommended method for switching between capture prescalers. This example also clears the prescaler counter and will not generate the "false" interrupt.
16.2.1
CCP PIN CONFIGURATION
In Capture mode, the RC2/CCP1 pin should be configured as an input by setting the TRISC<2> bit. Note: If the RC2/CCP1 is configured as an output, a write to the port can cause a capture condition.
EXAMPLE 16-1:
CLRF MOVLW
CHANGING BETWEEN CAPTURE PRESCALERS
Turn CCP module off Load WREG with the new prescaler mode value and CCP ON Load CCP1CON with this value
16.2.2
TIMER1/TIMER3 MODE SELECTION
The timers that are to be used with the capture feature (Timer1 and/or Timer3) must be running in Timer mode, or Synchronized Counter mode. In Asynchronous Counter mode, the capture operation may not work. The timer to be used with each CCP module is selected in the T3CON register (see Section 16.1.1).
MOVWF
CCP1CON, F ; NEW_CAPT_PS ; ; ; CCP1CON ; ;
FIGURE 16-2:
CAPTURE MODE OPERATION BLOCK DIAGRAM
Set Flag bit CCP1IF Prescaler / 1, 4, 16 TMR3H T3CCP2 TMR3 Enable CCPR1H and Edge Detect CCP1CON<3:0> Q's TMR1 Enable TMR1H TMR1L CCPR1L TMR3L
CCP1 pin
T3CCP2
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16.3 Compare Mode
16.3.2 TIMER1/TIMER3 MODE SELECTION
In Compare mode, the 16-bit CCPR1 register value is constantly compared against either the TMR1 register pair value, or the TMR3 register pair value. When a match occurs, the CCP1 pin is: * * * * driven High driven Low toggle output (High to Low or Low to High) remains unchanged Timer1 and/or Timer3 must be running in Timer mode, or Synchronized Counter mode, if the CCP module is using the compare feature. In Asynchronous Counter mode, the compare operation may not work.
16.3.3
SOFTWARE INTERRUPT MODE
The action on the pin is based on the value of control bits, CCP1M3:CCP1M0. At the same time, interrupt flag bit CCP1IF (CCP2IF) is set.
When generate software interrupt is chosen, the CCP1 pin is not affected. Only a CCP interrupt is generated (if enabled).
16.3.4
SPECIAL EVENT TRIGGER
16.3.1
CCP PIN CONFIGURATION
In this mode, an internal hardware trigger is generated, which may be used to initiate an action. The special event trigger output of either CCP1 or CCP2, resets the TMR1 or TMR3 register pair, depending on which timer resource is currently selected. This allows the CCPR1 register to effectively be a 16-bit programmable period register for Timer1 or Timer3. The CCP2 Special Event Trigger will also start an A/D conversion if the A/D module is enabled. Note: The special event trigger from the CCP2 module will not set the Timer1 or Timer3 interrupt flag bits.
The user must configure the CCPx pin as an output by clearing the appropriate TRIS bit. Note: Clearing the CCP1CON register will force the RC2/CCP1 compare output latch to the default low level. This is not the PORTC I/O data latch.
FIGURE 16-3:
COMPARE MODE OPERATION BLOCK DIAGRAM
For CCP1 and CCP2 only, the Special Event Trigger will: Reset Timer1 or Timer3, but not set Timer1 or Timer3 interrupt flag bit, and set bit, GO/DONE (ADCON0<2>) which starts an A/D conversion (CCP2 only) Special Event Trigger Set Flag bit CCP1IF CCPR1H CCPR1L Q RC2/CCP1 pin TRISC<2> Output Enable S R Output Logic Comparator
Match T3CCP2
CCP1CON<3:0> Mode Select
0
1
TMR1H
TMR1L
TMR3H
TMR3L
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TABLE 16-2:
Name INTCON RCON PIR1 PIE1 IPR1 PIR2 PIE2 IPR2 PIR3 PIE3 IPR3 TRISC TMR1L TMR1H T1CON TMR3H TMR3L T3CON CCPRxL(1) CCPRxH Legend:
(1)
REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, TIMER1 AND TIMER3
Bit 7 Bit 6 Bit 5 TMR0IE -- RCIF RCIE RCIP -- -- -- RC2IF RC2IE RC2IP Bit 4 INT0IE RI TXIF TXIE TXIP EEIE EEIF EEIP TX2IF TX2IE TX2IP Bit 3 RBIE TO SSPIF SSPIE SSPIP BCLIF BCLIE BCLIP TMR4IF TMR4IE TMR4IP Bit 2 TMR0IF PD CCP1IF CCP1IE CCP1IP LVDIF LVDIE LVDIP CCP5IF CCP5IE CCP5IP Bit 1 INT0IF POR TMR2IF TMR2IE TMR2IP TMR3IF TMR3IE TMR3IP CCP4IF CCP4IE CCP4IP Bit 0 RBIF BOR TMR1IF TMR1IE CCP2IF CCP2IE CCP2IP Value on POR, BOR Value on all other RESETS
GIE/GIEH PEIE/GIEL IPEN PSPIF PSPIE PSPIP -- -- -- -- -- -- -- ADIF ADIE ADIP CMIE CMIF CMIP -- -- --
0000 0000 0000 0000 0--1 11qq 0--q qquu 0000 0000 0000 0000 0000 0000 0000 0000
TMR1IP 0111 1111 0111 1111 -0-0 0000 ---0 0000 -0-0 0000 ---0 0000 -1-1 1111 ---1 1111
CCP3IF --00 0000 --00 0000 CCP3IE --00 0000 --00 0000 CCP3IP --11 1111 --11 1111 1111 1111 1111 1111 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu
PORTC Data Direction Register Holding Register for the Least Significant Byte of the 16-bit TMR1 Register Holding Register for the Most Significant Byte of the 16-bit TMR1 Register RD16 -- Timer3 Register High Byte Timer3 Register Low Byte RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 Capture/Compare/PWM Register x (LSB) Capture/Compare/PWM Register x (MSB) -- -- DCxB1 DCxB0 CCPxM3
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 u-uu uuuu
T3SYNC TMR3CS TMR3ON 0000 0000 uuuu uuuu xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu CCPxM2 CCPxM1 CCPxM0 --00 0000 --00 0000
CCPxCON(1)
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by Capture and Compare, Timer1 or Timer3. Note 1: Generic term for all of the identical registers of this name for all CCP modules, where `x' identifies the individual module (CCP1 through CCP5). Bit assignments and RESET values for all registers of the same generic name are identical.
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16.4 PWM Mode
16.4.1 PWM PERIOD
In Pulse Width Modulation (PWM) mode, the CCP1 pin produces up to a 10-bit resolution PWM output. Since the CCP1 pin is multiplexed with the PORTC data latch, the TRISC<2> bit must be cleared to make the CCP1 pin an output. Note: Clearing the CCP1CON register will force the CCP1 PWM output latch to the default low level. This is not the PORTC I/O data latch. The PWM period is specified by writing to the PR2 register. The PWM period can be calculated using the following formula: PWM period = (PR2) + 1] * 4 * TOSC * (TMR2 prescale value) PWM frequency is defined as 1 / [PWM period]. When TMR2 is equal to PR2, the following three events occur on the next increment cycle: * TMR2 is cleared * The CCP1 pin is set (exception: if PWM duty cycle = 0%, the CCP1 pin will not be set) * The PWM duty cycle is latched from CCPR1L into CCPR1H Note: The Timer2 and Timer4 postscalers (see Section 13.0) are not used in the determination of the PWM frequency. The postscaler could be used to have a servo update rate at a different frequency than the PWM output.
Figure 16-4 shows a simplified block diagram of the CCP module in PWM mode. For a step-by-step procedure on how to set up the CCP module for PWM operation, see Section 16.4.3.
FIGURE 16-4:
SIMPLIFIED PWM BLOCK DIAGRAM
CCP1CON<5:4>
Duty Cycle Registers CCPR1L
16.4.2
CCPR1H (Slave) R Q RC2/CCP1 TMR2 (Note 1) S TRISC<2> Clear Timer, CCP1 pin and latch D.C.
PWM DUTY CYCLE
Comparator
The PWM duty cycle is specified by writing to the CCPR1L register and to the CCP1CON<5:4> bits. Up to 10-bit resolution is available. The CCPR1L contains the eight MSbs and the CCP1CON<5:4> contains the two LSbs. This 10-bit value is represented by CCPR1L:CCP1CON<5:4>. The following equation is used to calculate the PWM duty cycle in time: PWM duty cycle = (CCPR1L:CCP1CON<5:4>) * TOSC * (TMR2 prescale value)
Comparator
PR2
Note: 8-bit timer is concatenated with 2-bit internal Q clock or 2 bits of the prescaler to create 10-bit time-base.
CCPR1L and CCP1CON<5:4> can be written to at any time, but the duty cycle value is not latched into CCPR1H until after a match between PR2 and TMR2 occurs (i.e., the period is complete). In PWM mode, CCPR1H is a read only register. The CCPR1H register and a 2-bit internal latch are used to double-buffer the PWM duty cycle. This doublebuffering is essential for glitchless PWM operation. When the CCPR1H and 2-bit latch match TMR2, concatenated with an internal 2-bit Q clock, or 2 bits of the TMR2 prescaler, the CCP1 pin is cleared. The maximum PWM resolution (bits) for a given PWM frequency is given by the equation: FOSC log --------------- FPWM PWM Resolution (max) = -----------------------------bits log ( 2 )
A PWM output (Figure 16-5) has a time-base (period) and a time that the output stays high (duty cycle). The frequency of the PWM is the inverse of the period (1/period).
FIGURE 16-5:
Period
PWM OUTPUT
Duty Cycle TMR2 = PR2 TMR2 = Duty Cycle TMR2 = PR2
Note:
If the PWM duty cycle value is longer than the PWM period, the CCP1 pin will not be cleared.
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16.4.3 SETUP FOR PWM OPERATION
The following steps should be taken when configuring the CCP module for PWM operation: 1. 2. 3. 4. 5. Set the PWM period by writing to the PR2 register. Set the PWM duty cycle by writing to the CCPR1L register and CCP1CON<5:4> bits. Make the CCP1 pin an output by clearing the TRISC<2> bit. Set the TMR2 prescale value and enable Timer2 by writing to T2CON. Configure the CCP1 module for PWM operation.
TABLE 16-3:
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
2.44 kHz 16 FFh 14 9.77 kHz 4 FFh 12 39.06 kHz 1 FFh 10 156.25 kHz 1 3Fh 8 312.50 kHz 1 1Fh 7 416.67 kHz 1 17h 6.58
PWM Frequency Timer Prescaler (1, 4, 16) PR2 Value Maximum Resolution (bits)
TABLE 16-4:
Name INTCON RCON PIR1 PIE1 IPR1 PIR2 PIE2 IPR2 PIR3 PIE3 IPR3 TMR2 PR2 T2CON T3CON TMR4 PR4 T4CON CCPRxL(1) CCPRxH(1) CCPxCON(1)
REGISTERS ASSOCIATED WITH PWM, TIMER2 AND TIMER4
Bit 7 Bit 6 Bit 5 TMR0IE -- RCIF RCIE RCIP -- -- -- RC2IF RC2IE RC2IP Bit 4 INT0IE RI TXIF TXIE TXIP EEIE EEIF EEIP TX2IF TX2IE TX2IP Bit 3 RBIE TO SSPIF SSPIE SSPIP BCLIF BCLIE BCLIP TMR4IF TMR4IE TMR4IP Bit 2 TMR0IF PD CCP1IF CCP1IE CCP1IP LVDIF LVDIE LVDIP CCP5IF CCP5IE CCP5IP Bit 1 INT0IF POR TMR2IF TMR2IE TMR2IP TMR3IF TMR3IE TMR3IP CCP4IF CCP4IE CCP4IP Bit 0 RBIF BOR Value on POR, BOR Value on all other RESETS
GIE/GIEH PEIE/GIEL IPEN PSPIF PSPIE PSPIP -- -- -- -- -- -- -- ADIF ADIE ADIP CMIE CMIF CMIP -- -- --
0000 0000 0000 0000 0--1 11qq 0--q qquu
TMR1IF 0000 0000 0000 0000 TMR1IE 0000 0000 0000 0000 TMR1IP 0111 1111 0111 1111 CCP2IF -0-0 0000 ---0 0000 CCP2IE -0-0 0000 ---0 0000 CCP2IP -1-1 1111 ---1 1111 CCP3IF --00 0000 --00 0000 CCP3IE --00 0000 --00 0000 CCP3IP --11 1111 --11 1111 0000 0000 0000 0000 1111 1111 1111 1111
Timer2 Module Register Timer2 Module Period Register -- RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000 T3SYNC TMR3CS TMR3ON 0000 0000 uuuu uuuu 0000 0000 uuuu uuuu 1111 1111 uuuu uuuu xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu CCPxM3 CCPxM2 CCPxM1 CCPxM0 --00 0000 --00 0000
Timer4 Register Timer4 Period Register -- Capture/Compare/PWM Register x (LSB) Capture/Compare/PWM Register x (MSB) -- -- DCxB1 DCxB0
T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 -000 0000 uuuu uuuu
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PWM, Timer2, or Timer4. Note 1: Generic term for all of the identical registers of this name for all CCP modules, where `x' identifies the individual module (CCP1 through CCP5). Bit assignments and RESET values for all registers of the same generic name are identical.
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NOTES:
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17.0 MASTER SYNCHRONOUS SERIAL PORT (MSSP) MODULE
Master SSP (MSSP) Module Overview 17.3 SPI Mode
The SPI mode allows 8 bits of data to be synchronously transmitted and received simultaneously. All four modes of SPI are supported. To accomplish communication, typically three pins are used: * Serial Data Out (SDO) - RC5/SDO * Serial Data In (SDI) - RC4/SDI/SDA * Serial Clock (SCK) - RC3/SCK/SCL/LVDIN Additionally, a fourth pin may be used when in a Slave mode of operation: * Slave Select (SS) - RF7/SS Figure 17-1 shows the block diagram of the MSSP module when operating in SPI mode.
17.1
The Master Synchronous Serial Port (MSSP) module is a serial interface, useful for communicating with other peripheral or microcontroller devices. These peripheral devices may be serial EEPROMs, shift registers, display drivers, A/D converters, etc. The MSSP module can operate in one of two modes: * Serial Peripheral Interface (SPI) * Inter-Integrated Circuit (I2C) - Full Master mode - Slave mode (with general address call) The I2C interface supports the following modes in hardware: * Master mode * Multi-Master mode * Slave mode
FIGURE 17-1:
MSSP BLOCK DIAGRAM (SPI MODE)
Internal Data Bus Read SSPBUF reg Write
17.2
Control Registers
The MSSP module has three associated registers. These include a status register (SSPSTAT) and two control registers (SSPCON1 and SSPCON2). The use of these registers and their individual configuration bits differ significantly, depending on whether the MSSP module is operated in SPI or I2C mode. Additional details are provided under the individual sections.
RC4/SDI/SDA SSPSR reg RC5/SDO bit0 Shift Clock
RF7/SS
SS Control Enable Edge Select 2 Clock Select SSPM3:SSPM0 SMP:CKE 4 TMR2 Output 2 2 Edge Select Prescaler TOSC 4, 16, 64
RC3/SCK/ SCL
(
)
Data to TX/RX in SSPSR TRIS bit
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17.3.1 REGISTERS
The MSSP module has four registers for SPI mode operation. These are: * * * * MSSP Control Register1 (SSPCON1) MSSP Status Register (SSPSTAT) Serial Receive/Transmit Buffer (SSPBUF) MSSP Shift Register (SSPSR) - Not directly accessible SSPSR is the shift register used for shifting data in or out. SSPBUF is the buffer register to which data bytes are written to or read from. In receive operations, SSPSR and SSPBUF together create a double-buffered receiver. When SSPSR receives a complete byte, it is transferred to SSPBUF and the SSPIF interrupt is set. During transmission, the SSPBUF is not doublebuffered. A write to SSPBUF will write to both SSPBUF and SSPSR.
SSPCON1 and SSPSTAT are the control and status registers in SPI mode operation. The SSPCON1 register is readable and writable. The lower 6 bits of the SSPSTAT are read only. The upper two bits of the SSPSTAT are read/write.
REGISTER 17-1:
SSPSTAT: MSSP STATUS REGISTER (SPI MODE)
R/W-0 SMP bit 7 R/W-0 CKE R-0 D/A R-0 P R-0 S R-0 R/W R-0 UA R-0 BF bit 0
bit 7
SMP: Sample bit SPI Master mode: 1 = Input data sampled at end of data output time 0 = Input data sampled at middle of data output time SPI Slave mode: SMP must be cleared when SPI is used in Slave mode CKE: SPI Clock Edge Select bit When CKP = 0: 1 = Data transmitted on rising edge of SCK 0 = Data transmitted on falling edge of SCK When CKP = 1: 1 = Data transmitted on falling edge of SCK 0 = Data transmitted on rising edge of SCK D/A: Data/Address bit Used in I2C mode only P: STOP bit Used in I2C mode only. This bit is cleared when the MSSP module is disabled, SSPEN is cleared. S: START bit Used in I2C mode only R/W: Read/Write bit information Used in I2C mode only UA: Update Address bit Used in I2C mode only BF: Buffer Full Status bit (Receive mode only) 1 = Receive complete, SSPBUF is full 0 = Receive not complete, SSPBUF is empty Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6
bit 5 bit 4
bit 3 bit 2 bit 1 bit 0
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REGISTER 17-2: SSPCON1: MSSP CONTROL REGISTER1 (SPI MODE)
R/W-0 WCOL bit 7 bit 7 WCOL: Write Collision Detect bit (Transmit mode only) 1 = The SSPBUF register is written while it is still transmitting the previous word (must be cleared in software) 0 = No collision SSPOV: Receive Overflow Indicator bit SPI Slave mode: 1 = A new byte is received while the SSPBUF register is still holding the previous data. In case of overflow, the data in SSPSR is lost. Overflow can only occur in Slave mode.The user must read the SSPBUF, even if only transmitting data, to avoid setting overflow (must be cleared in software). 0 = No overflow Note: bit 5 In Master mode, the overflow bit is not set, since each new reception (and transmission) is initiated by writing to the SSPBUF register. R/W-0 SSPOV R/W-0 SSPEN R/W-0 CKP R/W-0 SSPM3 R/W-0 SSPM2 R/W-0 SSPM1 R/W-0 SSPM0 bit 0
bit 6
SSPEN: Synchronous Serial Port Enable bit 1 = Enables serial port and configures SCK, SDO, SDI, and SS as serial port pins 0 = Disables serial port and configures these pins as I/O port pins Note: When enabled, these pins must be properly configured as input or output.
bit 4
CKP: Clock Polarity Select bit 1 = IDLE state for clock is a high level 0 = IDLE state for clock is a low level SSPM3:SSPM0: Synchronous Serial Port Mode Select bits 0101 = SPI Slave mode, clock = SCK pin, SS pin control disabled, SS can be used as I/O pin 0100 = SPI Slave mode, clock = SCK pin, SS pin control enabled 0011 = SPI Master mode, clock = TMR2 output/2 0010 = SPI Master mode, clock = FOSC/64 0001 = SPI Master mode, clock = FOSC/16 0000 = SPI Master mode, clock = FOSC/4 Note: Bit combinations not specifically listed here are either reserved, or implemented in I2C mode only.
bit 3-0
Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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17.3.2 OPERATION
When initializing the SPI, several options need to be specified. This is done by programming the appropriate control bits (SSPCON1<5:0> and SSPSTAT<7:6>). These control bits allow the following to be specified: Master mode (SCK is the clock output) Slave mode (SCK is the clock input) Clock Polarity (IDLE state of SCK) Data input sample phase (middle or end of data output time) * Clock edge (output data on rising/falling edge of SCK) * Clock Rate (Master mode only) * Slave Select mode (Slave mode only) The MSSP consists of a transmit/receive Shift Register (SSPSR) and a buffer register (SSPBUF). The SSPSR shifts the data in and out of the device, MSb first. The SSPBUF holds the data that was written to the SSPSR, until the received data is ready. Once the 8 bits of data have been received, that byte is moved to the SSPBUF register. Then the buffer full detect bit, BF (SSPSTAT<0>), and the interrupt flag bit, SSPIF, are set. This double-buffering of the received data (SSPBUF) allows the next byte to start reception before * * * * reading the data that was just received. Any write to the SSPBUF register during transmission/reception of data will be ignored, and the write collision detect bit, WCOL (SSPCON1<7>), will be set. User software must clear the WCOL bit so that it can be determined if the following write(s) to the SSPBUF register completed successfully. When the application software is expecting to receive valid data, the SSPBUF should be read before the next byte of data to transfer is written to the SSPBUF. Buffer full bit, BF (SSPSTAT<0>), indicates when SSPBUF has been loaded with the received data (transmission is complete). When the SSPBUF is read, the BF bit is cleared. This data may be irrelevant if the SPI is only a transmitter. Generally, the MSSP interrupt is used to determine when the transmission/reception has completed. The SSPBUF must be read and/or written. If the interrupt method is not going to be used, then software polling can be done to ensure that a write collision does not occur. Example 17-1 shows the loading of the SSPBUF (SSPSR) for data transmission. The SSPSR is not directly readable or writable, and can only be accessed by addressing the SSPBUF register. Additionally, the MSSP status register (SSPSTAT) indicates the various status conditions.
EXAMPLE 17-1:
LOADING THE SSPBUF (SSPSR) REGISTER
;Has data been received(transmit complete)? ;No ;WREG reg = contents of SSPBUF ;Save in user RAM, if data is meaningful ;W reg = contents of TXDATA ;New data to xmit
LOOP BTFSS SSPSTAT, BF BRA LOOP MOVF SSPBUF, W MOVWF RXDATA MOVF TXDATA, W MOVWF SSPBUF
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17.3.3 ENABLING SPI I/O 17.3.4 TYPICAL CONNECTION
To enable the serial port, SSP Enable bit, SSPEN (SSPCON1<5>), must be set. To reset or reconfigure SPI mode, clear the SSPEN bit, re-initialize the SSPCON registers, and then set the SSPEN bit. This configures the SDI, SDO, SCK, and SS pins as serial port pins. For the pins to behave as the serial port function, some must have their data direction bits (in the TRIS register) appropriately programmed as follows: * SDI is automatically controlled by the SPI module * SDO must have TRISC<5> bit cleared * SCK (Master mode) must have TRISC<3> bit cleared * SCK (Slave mode) must have TRISC<3> bit set * SS must have TRISF<7> bit set Any serial port function that is not desired may be overridden by programming the corresponding data direction (TRIS) register to the opposite value. Figure 17-2 shows a typical connection between two microcontrollers. The master controller (Processor 1) initiates the data transfer by sending the SCK signal. Data is shifted out of both shift registers on their programmed clock edge, and latched on the opposite edge of the clock. Both processors should be programmed to the same Clock Polarity (CKP), then both controllers would send and receive data at the same time. Whether the data is meaningful (or dummy data) depends on the application software. This leads to three scenarios for data transmission: * Master sends data -- Slave sends dummy data * Master sends data -- Slave sends data * Master sends dummy data -- Slave sends data
FIGURE 17-2:
SPI MASTER/SLAVE CONNECTION
SPI Master SSPM3:SSPM0 = 00xxb SDO SDI
SPI Slave SSPM3:SSPM0 = 010xb
Serial Input Buffer (SSPBUF)
Serial Input Buffer (SSPBUF)
Shift Register (SSPSR) MSb LSb
SDI
SDO
Shift Register (SSPSR) MSb LSb
SCK PROCESSOR 1
Serial Clock
SCK PROCESSOR 2
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17.3.5 MASTER MODE
The master can initiate the data transfer at any time because it controls the SCK. The master determines when the slave (Processor 2, Figure 17-2) is to broadcast data by the software protocol. In Master mode, the data is transmitted/received as soon as the SSPBUF register is written to. If the SPI is only going to receive, the SDO output could be disabled (programmed as an input). The SSPSR register will continue to shift in the signal present on the SDI pin at the programmed clock rate. As each byte is received, it will be loaded into the SSPBUF register as if a normal received byte (interrupts and status bits appropriately set). This could be useful in receiver applications as a "Line Activity Monitor" mode. The clock polarity is selected by appropriately programming the CKP bit (SSPCON1<4>). This then, would give waveforms for SPI communication, as shown in Figure 17-3, Figure 17-5, and Figure 17-6, where the MSB is transmitted first. In Master mode, the SPI clock rate (bit rate) is user programmable to be one of the following: * * * * FOSC/4 (or TCY) FOSC/16 (or 4 * TCY) FOSC/64 (or 16 * TCY) Timer2 output/2
This allows a maximum data rate (at 40 MHz) of 10.00 Mbps. Figure 17-3 shows the waveforms for Master mode. When the CKE bit is set, the SDO data is valid before there is a clock edge on SCK. The change of the input sample is shown based on the state of the SMP bit. The time when the SSPBUF is loaded with the received data is shown.
FIGURE 17-3:
Write to SSPBUF SCK (CKP = 0 CKE = 0) SCK (CKP = 1 CKE = 0) SCK (CKP = 0 CKE = 1) SCK (CKP = 1 CKE = 1) SDO (CKE = 0) SDO (CKE = 1) SDI (SMP = 0) Input Sample (SMP = 0) SDI (SMP = 1) Input Sample (SMP = 1) SSPIF SSPSR to SSPBUF
SPI MODE WAVEFORM (MASTER MODE)
4 Clock Modes
bit7 bit7
bit6 bit6
bit5 bit5
bit4 bit4
bit3 bit3
bit2 bit2
bit1 bit1
bit0 bit0
bit7
bit0
bit7
bit0
Next Q4 cycle after Q2
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17.3.6 SLAVE MODE
In Slave mode, the data is transmitted and received as the external clock pulses appear on SCK. When the last bit is latched, the SSPIF interrupt flag bit is set. While in Slave mode, the external clock is supplied by the external clock source on the SCK pin. This external clock must meet the minimum high and low times as specified in the electrical specifications. While in SLEEP mode, the slave can transmit/receive data. When a byte is received, the device will wake-up from SLEEP. the SDO pin is no longer driven, even if in the middle of a transmitted byte, and becomes a floating output. External pull-up/pull-down resistors may be desirable, depending on the application. Note 1: When the SPI is in Slave mode with SS pin control enabled (SSPCON<3:0> = 0100), the SPI module will reset if the SS pin is set to VDD. 2: If the SPI is used in Slave mode with CKE set, then the SS pin control must be enabled. When the SPI module resets, the bit counter is forced to `0'. This can be done by either forcing the SS pin to a high level or clearing the SSPEN bit. To emulate two-wire communication, the SDO pin can be connected to the SDI pin. When the SPI needs to operate as a receiver, the SDO pin can be configured as an input. This disables transmissions from the SDO. The SDI can always be left as an input (SDI function), since it cannot create a bus conflict.
17.3.7
SLAVE SELECT SYNCHRONIZATION
The SS pin allows a Synchronous Slave mode. The SPI must be in Slave mode with SS pin control enabled (SSPCON1<3:0> = 04h). The pin must not be driven low for the SS pin to function as an input. The Data Latch must be high. When the SS pin is low, transmission and reception are enabled and the SDO pin is driven. When the SS pin goes high,
FIGURE 17-4:
SS
SLAVE SYNCHRONIZATION WAVEFORM
SCK (CKP = 0 CKE = 0) SCK (CKP = 1 CKE = 0)
Write to SSPBUF
SDO
bit7
bit6
bit7
bit0
SDI (SMP = 0) Input Sample (SMP = 0) SSPIF Interrupt Flag SSPSR to SSPBUF
bit0 bit7 bit7
Next Q4 cycle after Q2
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FIGURE 17-5:
SS Optional SCK (CKP = 0 CKE = 0) SCK (CKP = 1 CKE = 0) Write to SSPBUF SDO SDI (SMP = 0) Input Sample (SMP = 0) SSPIF Interrupt Flag SSPSR to SSPBUF bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)
bit7
bit0
Next Q4 cycle after Q2
FIGURE 17-6:
SS Not Optional SCK (CKP = 0 CKE = 1) SCK (CKP = 1 CKE = 1) Write to SSPBUF SDO SDI (SMP = 0) Input Sample (SMP = 0) SSPIF Interrupt Flag SSPSR to SSPBUF
SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1)
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
bit7
bit0
Next Q4 cycle after Q2
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17.3.8 SLEEP OPERATION 17.3.10 BUS MODE COMPATIBILITY
In Master mode, all module clocks are halted and the transmission/reception will remain in that state until the device wakes from SLEEP. After the device returns to normal mode, the module will continue to transmit/receive data. In Slave mode, the SPI transmit/receive shift register operates asynchronously to the device. This allows the device to be placed in SLEEP mode and data to be shifted into the SPI transmit/receive shift register. When all 8 bits have been received, the MSSP interrupt flag bit will be set and if enabled, will wake the device from SLEEP. Table 17-1 shows the compatibility between the standard SPI modes and the states the CKP and CKE control bits.
TABLE 17-1:
SPI BUS MODES
Control Bits State CKP 0 0 1 1 CKE 1 0 1 0
Standard SPI Mode Terminology 0, 0, 1, 1, 0 1 0 1
17.3.9
EFFECTS OF A RESET
A RESET disables the MSSP module and terminates the current transfer.
There is also a SMP bit, which controls when the data is sampled.
TABLE 17-2:
Name INTCON PIR1 PIE1 IPR1 TRISC TRISF SSPBUF SSPCON SSPSTAT
REGISTERS ASSOCIATED WITH SPI OPERATION
Bit 7 Bit 6 Bit 5 TMR0IE RCIF RCIE RCIP TRISF5 SSPEN D/A Bit 4 INT0IE TXIF TXIE TXIP TRISF4 CKP P Bit 3 RBIE SSPIF SSPIE SSPIP TRISF3 SSPM3 S Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP TRISF2 SSPM2 R/W Bit 1 INT0IF TMR2IF TMR2IE TMR2IP TRISF1 SSPM1 UA Bit 0 RBIF Value on POR, BOR Value on all other RESETS
GIE/GIEH PEIE/GIEL PSPIF PSPIE PSPIP TRISF7 WCOL SMP ADIF ADIE ADIP TRISF6 SSPOV CKE
0000 0000 0000 0000
TMR1IF 0000 0000 0000 0000 TMR1IE 0000 0000 0000 0000 TMR1IP 0111 1111 0111 1111 1111 1111 1111 1111 TRISF0 1111 1111 uuuu uuuu xxxx xxxx uuuu uuuu SSPM0 BF 0000 0000 0000 0000 0000 0000 0000 0000
PORTC Data Direction Register Synchronous Serial Port Receive Buffer/Transmit Register
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the MSSP in SPI mode.
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DS39609A-page 165
PIC18FXX20
17.4 I2C Mode
17.4.1 REGISTERS
The MSSP module in I 2C mode fully implements all master and slave functions (including general call support) and provides interrupts on START and STOP bits in hardware to determine a free bus (multi-master function). The MSSP module implements the standard mode specifications, as well as 7-bit and 10-bit addressing. Two pins are used for data transfer: * Serial clock (SCL) - RC3/SCK/SCL * Serial data (SDA) - RC4/SDI/SDA The user must configure these pins as inputs or outputs through the TRISC<4:3> bits. The MSSP module has six registers for I2C operation. These are: * * * * * MSSP Control Register1 (SSPCON1) MSSP Control Register2 (SSPCON2) MSSP Status Register (SSPSTAT) Serial Receive/Transmit Buffer (SSPBUF) MSSP Shift Register (SSPSR) - Not directly accessible * MSSP Address Register (SSPADD) SSPCON, SSPCON2 and SSPSTAT are the control and status registers in I2C mode operation. The SSPCON and SSPCON2 registers are readable and writable. The lower 6 bits of the SSPSTAT are read only. The upper two bits of the SSPSTAT are read/write. SSPSR is the shift register used for shifting data in or out. SSPBUF is the buffer register to which data bytes are written to or read from. SSPADD register holds the slave device address when the SSP is configured in I2C Slave mode. When the SSP is configured in Master mode, the lower seven bits of SSPADD act as the baud rate generator reload value. In receive operations, SSPSR and SSPBUF together, create a double-buffered receiver. When SSPSR receives a complete byte, it is transferred to SSPBUF and the SSPIF interrupt is set. During transmission, the SSPBUF is not doublebuffered. A write to SSPBUF will write to both SSPBUF and SSPSR.
FIGURE 17-7:
MSSP BLOCK DIAGRAM (I2C MODE)
Internal Data Bus Read SSPBUF reg Shift Clock SSPSR reg Write
RC3/SCK/SCL
RC4/ SDI/ SDA
MSb
LSb
Match Detect
Addr Match
SSPADD reg START and STOP bit Detect Set, Reset S, P bits (SSPSTAT reg)
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REGISTER 17-3: SSPSTAT: MSSP STATUS REGISTER (I2C MODE)
R/W-0 SMP bit 7 bit 7 SMP: Slew Rate Control bit In Master or Slave mode: 1 = Slew rate control disabled for Standard Speed mode (100 kHz and 1 MHz) 0 = Slew rate control enabled for High Speed mode (400 kHz) CKE: SMBus Select bit In Master or Slave mode: 1 = Enable SMBus specific inputs 0 = Disable SMBus specific inputs D/A: Data/Address bit In Master mode: Reserved In Slave mode: 1 = Indicates that the last byte received or transmitted was data 0 = Indicates that the last byte received or transmitted was address P: STOP bit 1 = Indicates that a STOP bit has been detected last 0 = STOP bit was not detected last Note: This bit is cleared on RESET and when SSPEN is cleared. S: START bit 1 = Indicates that a START bit has been detected last 0 = START bit was not detected last Note: This bit is cleared on RESET and when SSPEN is cleared. R/W: Read/Write bit Information (I2C mode only) In Slave mode: 1 = Read 0 = Write Note: This bit holds the R/W bit information following the last address match. This bit is only valid from the address match to the next START bit, STOP bit, or not ACK bit. In Master mode: 1 = Transmit is in progress 0 = Transmit is not in progress Note: ORing this bit with SEN, RSEN, PEN, RCEN, or ACKEN will indicate if the MSSP is in IDLE mode. bit 1 UA: Update Address bit (10-bit Slave mode only) 1 = Indicates that the user needs to update the address in the SSPADD register 0 = Address does not need to be updated BF: Buffer Full Status bit In Transmit mode: 1 = Receive complete, SSPBUF is full 0 = Receive not complete, SSPBUF is empty In Receive mode: 1 = Data transmit in progress (does not include the ACK and STOP bits), SSPBUF is full 0 = Data transmit complete (does not include the ACK and STOP bits), SSPBUF is empty Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown R/W-0 CKE R-0 D/A R-0 P R-0 S R-0 R/W R-0 UA R-0 BF bit 0
bit 6
bit 5
bit 4
bit 3
bit 2
bit 0
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DS39609A-page 167
PIC18FXX20
REGISTER 17-4: SSPCON1: MSSP CONTROL REGISTER1 (I2C MODE)
R/W-0 WCOL bit 7 bit 7 R/W-0 SSPOV R/W-0 SSPEN R/W-0 CKP R/W-0 SSPM3 R/W-0 SSPM2 R/W-0 SSPM1 R/W-0 SSPM0 bit 0
WCOL: Write Collision Detect bit In Master Transmit mode: 1 = A write to the SSPBUF register was attempted while the I2C conditions were not valid for a transmission to be started (must be cleared in software) 0 = No collision In Slave Transmit mode: 1 = The SSPBUF register is written while it is still transmitting the previous word (must be cleared in software) 0 = No collision In Receive mode (Master or Slave modes): This is a "don't care" bit SSPOV: Receive Overflow Indicator bit In Receive mode: 1 = A byte is received while the SSPBUF register is still holding the previous byte (must be cleared in software) 0 = No overflow In Transmit mode: This is a "don't care" bit in Transmit mode SSPEN: Synchronous Serial Port Enable bit 1 = Enables the serial port and configures the SDA and SCL pins as the serial port pins 0 = Disables serial port and configures these pins as I/O port pins Note: When enabled, the SDA and SCL pins must be properly configured as input or output.
bit 6
bit 5
bit 4
CKP: SCK Release Control bit In Slave mode: 1 = Release clock 0 = Holds clock low (clock stretch), used to ensure data setup time In Master mode: Unused in this mode SSPM3:SSPM0: Synchronous Serial Port Mode Select bits 1111 = I2C Slave mode, 10-bit address with START and STOP bit interrupts enabled 1110 = I2C Slave mode, 7-bit address with START and STOP bit interrupts enabled 1011 = I2C Firmware Controlled Master mode (Slave IDLE) 1000 = I2C Master mode, clock = FOSC / (4 * (SSPADD+1)) 0111 = I2C Slave mode, 10-bit address 0110 = I2C Slave mode, 7-bit address Note: Bit combinations not specifically listed here are either reserved, or implemented in SPI mode only.
bit 3-0
Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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REGISTER 17-5: SSPCON2: MSSP CONTROL REGISTER 2 (I2C MODE)
R/W-0 GCEN bit 7 bit 7 GCEN: General Call Enable bit (Slave mode only) 1 = Enable interrupt when a general call address (0000h) is received in the SSPSR 0 = General call address disabled ACKSTAT: Acknowledge Status bit (Master Transmit mode only) 1 = Acknowledge was not received from slave 0 = Acknowledge was received from slave ACKDT: Acknowledge Data bit (Master Receive mode only) 1 = Not Acknowledge 0 = Acknowledge Note: bit 4 Value that will be transmitted when the user initiates an Acknowledge sequence at the end of a receive. R/W-0 ACKSTAT R/W-0 ACKDT R/W-0 ACKEN R/W-0 RCEN R/W-0 PEN R/W-0 RSEN R/W-0 SEN bit 0
bit 6
bit 5
ACKEN: Acknowledge Sequence Enable bit (Master Receive mode only) 1 = Initiate Acknowledge sequence on SDA and SCL pins, and transmit ACKDT data bit. Automatically cleared by hardware. 0 = Acknowledge sequence IDLE RCEN: Receive Enable bit (Master Mode only) 1 = Enables Receive mode for I2C 0 = Receive IDLE PEN: STOP Condition Enable bit (Master mode only) 1 = Initiate STOP condition on SDA and SCL pins. Automatically cleared by hardware. 0 = STOP condition IDLE
bit 3
bit 2
bit 1
RSEN: Repeated START Condition Enabled bit (Master mode only) 1 = Initiate Repeated START condition on SDA and SCL pins. Automatically cleared by hardware. 0 = Repeated START condition IDLE SEN: START Condition Enabled/Stretch Enabled bit In Master mode: 1 = Initiate START condition on SDA and SCL pins. Automatically cleared by hardware. 0 = START condition IDLE In Slave mode: 1 = Clock stretching is enabled for both Slave Transmit and Slave Receive (stretch enabled) 0 = Clock stretching is disabled Note: For bits ACKEN, RCEN, PEN, RSEN, SEN: If the I2C module is not in the IDLE mode, this bit may not be set (no spooling) and the SSPBUF may not be written (or writes to the SSPBUF are disabled).
bit 0
Legend: R = Readable bit - n = Value at POR reset W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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17.4.2 OPERATION 17.4.3.1 Addressing
The MSSP module functions are enabled by setting MSSP Enable bit, SSPEN (SSPCON<5>). The SSPCON1 register allows control of the I 2C operation. Four mode selection bits (SSPCON<3:0>) allow one of the following I 2C modes to be selected: * * * * I2C Master mode, clock = (FOSC / 4) x (SSPADD +1) I 2C Slave mode (7-bit address) I 2C Slave mode (10-bit address) I 2C Slave mode (7-bit address), with START and STOP bit interrupts enabled * I 2C Slave mode (10-bit address), with START and STOP bit interrupts enabled * I 2C Firmware controlled master operation, slave is IDLE Once the MSSP module has been enabled, it waits for a START condition to occur. Following the START condition, the 8-bits are shifted into the SSPSR register. All incoming bits are sampled with the rising edge of the clock (SCL) line. The value of register SSPSR<7:1> is compared to the value of the SSPADD register. The address is compared on the falling edge of the eighth clock (SCL) pulse. If the addresses match, and the BF and SSPOV bits are clear, the following events occur: 1. 2. 3. 4. The SSPSR register value is loaded into the SSPBUF register. The buffer full bit BF is set. An ACK pulse is generated. MSSP interrupt flag bit, SSPIF (PIR1<3>), is set (interrupt is generated, if enabled) on the falling edge of the ninth SCL pulse.
Selection of any I 2C mode, with the SSPEN bit set, forces the SCL and SDA pins to be open drain, provided these pins are programmed to inputs by setting the appropriate TRISC bits. To ensure proper operation of the module, pull-up resistors must be provided externally to the SCL and SDA pins.
17.4.3
SLAVE MODE
In Slave mode, the SCL and SDA pins must be configured as inputs (TRISC<4:3> set). The MSSP module will override the input state with the output data when required (slave-transmitter). Slave mode hardware will always generate an The I interrupt on an address match. Through the mode select bits, the user can also choose to interrupt on START and STOP bits When an address is matched or the data transfer after an address match is received, the hardware automatically will generate the Acknowledge (ACK) pulse and load the SSPBUF register with the received value currently in the SSPSR register. Any combination of the following conditions will cause the MSSP module not to give this ACK pulse: * The buffer full bit BF (SSPSTAT<0>) was set before the transfer was received. * The overflow bit SSPOV (SSPCON<6>) was set before the transfer was received. In this case, the SSPSR register value is not loaded into the SSPBUF, but bit SSPIF (PIR1<3>) is set. The BF bit is cleared by reading the SSPBUF register, while bit SSPOV is cleared through software. The SCL clock input must have a minimum high and low for proper operation. The high and low times of the I2C specification, as well as the requirement of the MSSP module, are shown in timing parameter #100 and parameter #101.
2C
In 10-bit Address mode, two address bytes need to be received by the slave. The five Most Significant bits (MSbs) of the first address byte specify if this is a 10-bit address. Bit R/W (SSPSTAT<2>) must specify a write so the slave device will receive the second address byte. For a 10-bit address, the first byte would equal `11110 A9 A8 0', where `A9' and `A8' are the two MSbs of the address. The sequence of events for 10-bit address is as follows, with steps 7 through 9 for the slave-transmitter: 1. 2. Receive first (high) byte of Address (bits SSPIF, BF and bit UA (SSPSTAT<1>) are set). Update the SSPADD register with second (low) byte of Address (clears bit UA and releases the SCL line). Read the SSPBUF register (clears bit BF) and clear flag bit SSPIF. Receive second (low) byte of Address (bits SSPIF, BF, and UA are set). Update the SSPADD register with the first (high) byte of Address. If match releases SCL line, this will clear bit UA. Read the SSPBUF register (clears bit BF) and clear flag bit SSPIF. Receive Repeated START condition. Receive first (high) byte of Address (bits SSPIF and BF are set). Read the SSPBUF register (clears bit BF) and clear flag bit SSPIF.
3. 4. 5.
6. 7. 8. 9.
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PIC18FXX20
17.4.3.2 Reception
When the R/W bit of the address byte is clear and an address match occurs, the R/W bit of the SSPSTAT register is cleared. The received address is loaded into the SSPBUF register and the SDA line is held low (ACK). When the address byte overflow condition exists, then the No Acknowledge (ACK) pulse is given. An overflow condition is defined as either bit BF (SSPSTAT<0>) is set, or bit SSPOV (SSPCON1<6>) is set. An MSSP interrupt is generated for each data transfer byte. Flag bit SSPIF (PIR1<3>) must be cleared in software. The SSPSTAT register is used to determine the status of the byte. If SEN is enabled (SSPCON1<0> = 1), RC3/SCK/SCL will be held low (clock stretch) following each data transfer. The clock must be released by setting bit CKP (SSPCON<4>). See Section 17.4.4 ("Clock Stretching"), for more detail. The ACK pulse from the master-receiver is latched on the rising edge of the ninth SCL input pulse. If the SDA line is high (not ACK), then the data transfer is complete. In this case, when the ACK is latched by the slave, the slave logic is reset (resets SSPSTAT register) and the slave monitors for another occurrence of the START bit. If the SDA line was low (ACK), the next transmit data must be loaded into the SSPBUF register. Again, pin RC3/SCK/SCL must be enabled by setting bit CKP. An MSSP interrupt is generated for each data transfer byte. The SSPIF bit must be cleared in software and the SSPSTAT register is used to determine the status of the byte. The SSPIF bit is set on the falling edge of the ninth clock pulse.
17.4.3.3
Transmission
When the R/W bit of the incoming address byte is set and an address match occurs, the R/W bit of the SSPSTAT register is set. The received address is loaded into the SSPBUF register. The ACK pulse will be sent on the ninth bit and pin RC3/SCK/SCL is held low, regardless of SEN (see "Clock Stretching", Section 17.4.4, for more detail). By stretching the clock, the master will be unable to assert another clock pulse until the slave is done preparing the transmit data.The transmit data must be loaded into the SSPBUF register, which also loads the SSPSR register. Then pin RC3/SCK/SCL should be enabled by setting bit CKP (SSPCON1<4>). The eight data bits are shifted out on the falling edge of the SCL input. This ensures that the SDA signal is valid during the SCL high time (Figure 17-9).
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FIGURE 17-8:
DS39609A-page 172
Receiving Address A5 A4 A3 A2 A1 ACK D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 R/W = 0 Receiving Data ACK Receiving Data D1 D0 ACK 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P Bus Master terminates transfer Cleared in software SSPBUF is read SSPOV is set because SSPBUF is still full. ACK is not sent.
PIC18FXX20
SDA
A7
A6
SCL
S
1
2
SSPIF
(PIR1<3>)
I2C SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 7-BIT ADDRESS)
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BF (SSPSTAT<0>)
SSPOV (SSPCON<6>)
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CKP
(CKP does not reset to `0' when SEN = 0)
FIGURE 17-9:
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R/W = 1 ACK D1 D0 D4 D3 D5 D7 D6 A1 D3 D2 ACK D5 D4 D7 D6 D2 Transmitting Data Transmitting Data D1 D0 ACK A4 A2 A3 4 SCL held low while CPU responds to SSPIF 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P Cleared in software SSPBUF is written in software From SSPIF ISR Cleared in software SSPBUF is written in software From SSPIF ISR CKP is set in software CKP is set in software
Receiving Address
SDA
A7
A6
A5
SCL
S
1
2
3
Data in sampled
SSPIF (PIR1<3>)
I2C SLAVE MODE TIMING (TRANSMISSION, 7-BIT ADDRESS)
Advance Information
BF (SSPSTAT<0>)
CKP
PIC18FXX20
DS39609A-page 173
FIGURE 17-10:
DS39609A-page 174
Clock is held low until update of SSPADD has taken place R/W = 0 ACK A7 D3 D2 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 ACK D7 D6 D5 D4 A0 ACK Receive Second Byte of Address Receive Data Byte Receive Data Byte D1 D0 ACK Clock is held low until update of SSPADD has taken place 0 A9 A8 5 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 6 7 8 9 P Bus Master terminates transfer Cleared in software Cleared in software Cleared in software Dummy read of SSPBUF to clear BF flag SSPOV is set because SSPBUF is still full. ACK is not sent. Cleared by hardware when SSPADD is updated with low byte of address UA is set indicating that SSPADD needs to be updated Cleared by hardware when SSPADD is updated with high byte of address
Receive First Byte of Address
PIC18FXX20
SDA
1
1
1
1
SCL
S
1
2
3
4
SSPIF
(PIR1<3>)
Cleared in software
BF (SSPSTAT<0>)
SSPBUF is written with contents of SSPSR
SSPOV (SSPCON<6>)
I2C SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 10-BIT ADDRESS)
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UA (SSPSTAT<1>)
UA is set indicating that the SSPADD needs to be updated
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CKP
(CKP does not reset to `0' when SEN = 0)
FIGURE 17-11:
Bus Master terminates transfer Clock is held low until CKP is set to `1' R/W = 1 ACK Transmitting Data Byte D7 D6 D5 D4 D3 D2 D1 D0 ACK
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Clock is held low until update of SSPADD has taken place R/W = 0 Receive Second Byte of Address Receive First Byte of Address ACK 1 1 1 1 0 A9 A8 ACK A7 A6 A5 A4 A3 A2 A1 A0 1 0 A9 A8 Clock is held low until update of SSPADD has taken place 4 Sr 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P Cleared in software Cleared in software Cleared in software Dummy read of SSPBUF to clear BF flag Dummy read of SSPBUF to clear BF flag Write of SSPBUF BF flag is clear initiates transmit at the end of the third address sequence Completion of data transmission clears BF flag Cleared by hardware when SSPADD is updated with low byte of address UA is set indicating that SSPADD needs to be updated Cleared by hardware when SSPADD is updated with high byte of address CKP is set in software CKP is automatically cleared in hardware, holding SCL low
Receive First Byte of Address
SDA
1
1
1
SCL
S
1
2
3
SSPIF
(PIR1<3>)
BF (SSPSTAT<0>)
SSPBUF is written with contents of SSPSR
I2C SLAVE MODE TIMING (TRANSMISSION, 10-BIT ADDRESS)
Advance Information
UA (SSPSTAT<1>)
UA is set indicating that the SSPADD needs to be updated
PIC18FXX20
CKP (SSPCON<4>)
DS39609A-page 175
PIC18FXX20
17.4.4 CLOCK STRETCHING 17.4.4.3
Both 7- and 10-bit Slave modes implement automatic clock stretching during a transmit sequence. The SEN bit (SSPCON2<0>) allows clock stretching to be enabled during receives. Setting SEN will cause the SCL pin to be held low at the end of each data receive sequence.
Clock Stretching for 7-bit Slave Transmit Mode
7-bit Slave Transmit mode implements clock stretching by clearing the CKP bit after the falling edge of the ninth clock, if the BF bit is clear. This occurs, regardless of the state of the SEN bit. The user's ISR must set the CKP bit before transmission is allowed to continue. By holding the SCL line low, the user has time to service the ISR and load the contents of the SSPBUF before the master device can initiate another transmit sequence (see Figure 17-9). Note 1: If the user loads the contents of SSPBUF, setting the BF bit before the falling edge of the ninth clock, the CKP bit will not be cleared and clock stretching will not occur. 2: The CKP bit can be set in software, regardless of the state of the BF bit.
17.4.4.1
Clock Stretching for 7-bit Slave Receive Mode (SEN = 1)
In 7-bit Slave Receive mode, on the falling edge of the ninth clock at the end of the ACK sequence, if the BF bit is set, the CKP bit in the SSPCON1 register is automatically cleared, forcing the SCL output to be held low. The CKP being cleared to `0' will assert the SCL line low. The CKP bit must be set in the user's ISR before reception is allowed to continue. By holding the SCL line low, the user has time to service the ISR and read the contents of the SSPBUF before the master device can initiate another receive sequence. This will prevent buffer overruns from occurring (see Figure 17-13). Note 1: If the user reads the contents of the SSPBUF before the falling edge of the ninth clock, thus clearing the BF bit, the CKP bit will not be cleared and clock stretching will not occur. 2: The CKP bit can be set in software, regardless of the state of the BF bit. The user should be careful to clear the BF bit in the ISR before the next receive sequence, in order to prevent an overflow condition.
17.4.4.4
Clock Stretching for 10-bit Slave Transmit Mode
In 10-bit Slave Transmit mode, clock stretching is controlled during the first two address sequences by the state of the UA bit, just as it is in 10-bit Slave Receive mode. The first two addresses are followed by a third address sequence, which contains the high order bits of the 10-bit address and the R/W bit set to `1'. After the third address sequence is performed, the UA bit is not set, the module is now configured in Transmit mode, and clock stretching is controlled by the BF flag, as in 7-bit Slave Transmit mode (see Figure 17-11).
17.4.4.2
Clock Stretching for 10-bit Slave Receive Mode (SEN = 1)
In 10-bit Slave Receive mode, during the address sequence, clock stretching automatically takes place but CKP is not cleared. During this time, if the UA bit is set after the ninth clock, clock stretching is initiated. The UA bit is set after receiving the upper byte of the 10-bit address, and following the receive of the second byte of the 10-bit address with the R/W bit cleared to `0'. The release of the clock line occurs upon updating SSPADD. Clock stretching will occur on each data receive sequence, as described in 7-bit mode. Note: If the user polls the UA bit and clears it by updating the SSPADD register before the falling edge of the ninth clock occurs, and if the user hasn't cleared the BF bit by reading the SSPBUF register before that time, then the CKP bit will still NOT be asserted low. Clock stretching on the basis of the state of the BF bit only occurs during a data sequence, not an address sequence.
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17.4.4.5 Clock Synchronization and the CKP bit
When the CKP bit is cleared, the SCL output is forced to `0'. However, setting the CKP bit will not assert the SCL output low until the SCL output is already sampled low. Therefore, the CKP bit will not assert the SCL line until an external I2C master device has already asserted the SCL line. The SCL output will remain low until the CKP bit is set, and all other devices on the I2C bus have de-asserted SCL. This ensures that a write to the CKP bit will not violate the minimum high time requirement for SCL (see Figure 17-12).
FIGURE 17-12:
CLOCK SYNCHRONIZATION TIMING
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SDA
DX
DX-1
SCL
CKP
Master device asserts clock Master device de-asserts clock
WR SSPCON
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FIGURE 17-13:
DS39609A-page 178
Clock is not held low because buffer full bit is clear prior to falling edge of 9th clock Clock is held low until CKP is set to `1' ACK Receiving Data D7 D6 D5 D4 D3 D2 D1 D0 D2 D1 D0 Receiving Address A5 A4 A3 A2 A1 ACK D7 D6 D5 D4 D3 R/W = 0 Receiving Data Clock is not held low because ACK = 1 ACK 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P Bus Master terminates transfer Cleared in software SSPBUF is read SSPOV is set because SSPBUF is still full. ACK is not sent.
PIC18FXX20
SDA
A7
A6
SCL
S
1
2
SSPIF
(PIR1<3>)
I2C SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 7-BIT ADDRESS)
Advance Information
If BF is cleared prior to the falling edge of the 9th clock, CKP will not be reset to `0' and no clock stretching will occur BF is set after falling edge of the 9th clock, CKP is reset to `0' and clock stretching occurs CKP written to `1' in software
BF (SSPSTAT<0>)
SSPOV (SSPCON<6>)
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CKP
FIGURE 17-14:
Clock is held low until update of SSPADD has taken place Clock is held low until CKP is set to `1' Receive Data Byte D1 D0 D7 D6 D5 D4 ACK D3 D2 D1 D0 R/W = 0 ACK A7 A6 A5 A4 A3 A2 A1 A0 ACK D7 D6 D5 D4 D3 D2 Receive Second Byte of Address Receive Data Byte
Clock is held low until update of SSPADD has taken place
Clock is not held low because ACK = 1 ACK
Receive First Byte of Address A9 A8
2003 Microchip Technology Inc.
6 1 2 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 3 4 5 6 7 8 9 P Cleared in software Cleared in software Cleared in software Bus Master terminates transfer Dummy read of SSPBUF to clear BF flag Dummy read of SSPBUF to clear BF flag SSPOV is set because SSPBUF is still full. ACK is not sent. Cleared by hardware when SSPADD is updated with low byte of address after falling edge of ninth clock UA is set indicating that SSPADD needs to be updated Note: Cleared by hardware when SSPADD is updated with high byte of address after falling edge of ninth clock An update of the SSPADD register before the falling edge of the ninth clock will have no effect on UA, and UA will remain set Note: An update of the SSPADD register before the falling edge of the ninth clock will have no effect on UA, and UA will remain set CKP written to `1' in software
SDA
1
1
1
1
0
SCL
S
1
2
3
4
5
SSPIF
(PIR1<3>)
Cleared in software
BF (SSPSTAT<0>)
SSPBUF is written with contents of SSPSR
SSPOV (SSPCON<6>)
I2C SLAVE MODE TIMING SEN = 1 (RECEPTION, 10-BIT ADDRESS)
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UA (SSPSTAT<1>)
UA is set indicating that the SSPADD needs to be updated
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CKP
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17.4.5 GENERAL CALL ADDRESS SUPPORT
The addressing procedure for the I2C bus is such that the first byte after the START condition usually determines which device will be the slave addressed by the master. The exception is the general call address, which can address all devices. When this address is used, all devices should, in theory, respond with an Acknowledge. The general call address is one of eight addresses reserved for specific purposes by the I2C protocol. It consists of all 0's with R/W = 0. The general call address is recognized when the General Call Enable bit (GCEN) is enabled (SSPCON2<7> set). Following a START bit detect, 8-bits are shifted into the SSPSR and the address is compared against the SSPADD. It is also compared to the general call address and fixed in hardware. If the general call address matches, the SSPSR is transferred to the SSPBUF, the BF flag bit is set (eighth bit), and on the falling edge of the ninth bit (ACK bit), the SSPIF interrupt flag bit is set. When the interrupt is serviced, the source for the interrupt can be checked by reading the contents of the SSPBUF. The value can be used to determine if the address was device specific or a general call address. In 10-bit mode, the SSPADD is required to be updated for the second half of the address to match, and the UA bit is set (SSPSTAT<1>). If the general call address is sampled when the GCEN bit is set, while the slave is configured in 10-bit Address mode, then the second half of the address is not necessary, the UA bit will not be set, and the slave will begin receiving data after the Acknowledge (Figure 17-15).
FIGURE 17-15:
SLAVE MODE GENERAL CALL ADDRESS SEQUENCE (7 OR 10-BIT ADDRESS MODE)
Address is compared to General Call Address after ACK, set interrupt R/W = 0 ACK D7 Receiving Data D6 D5 D4 D3 D2 D1 D0 ACK
SDA SCL S SSPIF BF (SSPSTAT<0>)
General Call Address
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
Cleared in software SSPBUF is read SSPOV (SSPCON1<6>) '0'
GCEN (SSPCON2<7>)
'1'
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17.4.6 MASTER MODE
Note: Master mode is enabled by setting and clearing the appropriate SSPM bits in SSPCON1 and by setting the SSPEN bit. In Master mode, the SCL and SDA lines are manipulated by the MSSP hardware. Master mode of operation is supported by interrupt generation on the detection of the START and STOP conditions. The STOP (P) and START (S) bits are cleared from a RESET, or when the MSSP module is disabled. Control of the I 2C bus may be taken when the P bit is set or the bus is IDLE, with both the S and P bits clear. In Firmware Controlled Master mode, user code conducts all I 2C bus operations based on START and STOP bit conditions. Once Master mode is enabled, the user has six options. 1. 2. 3. 4. 5. 6. Assert a START condition on SDA and SCL. Assert a Repeated START condition on SDA and SCL. Write to the SSPBUF register initiating transmission of data/address. Configure the I2C port to receive data. Generate an Acknowledge condition at the end of a received byte of data. Generate a STOP condition on SDA and SCL. The MSSP Module, when configured in I2C Master mode, does not allow queueing of events. For instance, the user is not allowed to initiate a START condition and immediately write the SSPBUF register to initiate transmission before the START condition is complete. In this case, the SSPBUF will not be written to and the WCOL bit will be set, indicating that a write to the SSPBUF did not occur.
The following events will cause SSP interrupt flag bit, SSPIF, to be set (SSP interrupt if enabled): * * * * * START condition STOP condition Data transfer byte transmitted/received Acknowledge Transmit Repeated START
FIGURE 17-16:
MSSP BLOCK DIAGRAM (I2C MASTER MODE)
Internal Data Bus Read SSPBUF Write Baud Rate Generator Clock Arbitrate/WCOL Detect (hold off clock source) DS39609A-page 181 Shift Clock SSPSR Receive Enable MSb LSb SSPM3:SSPM0 SSPADD<6:0>
SDA
SDA In
SCL
SCL In Bus Collision
START bit Detect STOP bit Detect Write Collision Detect Clock Arbitration State Counter for end of XMIT/RCV
Set/Reset, S, P, WCOL (SSPSTAT) Set SSPIF, BCLIF Reset ACKSTAT, PEN (SSPCON2)
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Clock Cntl
START bit, STOP bit, Acknowledge Generate
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17.4.6.1 I2C Master Mode Operation
A typical transmit sequence would go as follows: 1. The user generates a START condition by setting the START enable bit, SEN (SSPCON2<0>). 2. SSPIF is set. The MSSP module will wait the required start time before any other operation takes place. 3. The user loads the SSPBUF with the slave address to transmit. 4. Address is shifted out the SDA pin until all 8 bits are transmitted. 5. The MSSP Module shifts in the ACK bit from the slave device and writes its value into the SSPCON2 register (SSPCON2<6>). 6. The MSSP module generates an interrupt at the end of the ninth clock cycle by setting the SSPIF bit. 7. The user loads the SSPBUF with eight bits of data. 8. Data is shifted out the SDA pin until all 8 bits are transmitted. 9. The MSSP Module shifts in the ACK bit from the slave device and writes its value into the SSPCON2 register (SSPCON2<6>). 10. The MSSP module generates an interrupt at the end of the ninth clock cycle by setting the SSPIF bit. 11. The user generates a STOP condition by setting the STOP enable bit PEN (SSPCON2<2>). 12. Interrupt is generated once the STOP condition is complete. The master device generates all of the serial clock pulses and the START and STOP conditions. A transfer is ended with a STOP condition or with a Repeated START condition. Since the Repeated START condition is also the beginning of the next serial transfer, the I2C bus will not be released. In Master Transmitter mode, serial data is output through SDA, while SCL outputs the serial clock. The first byte transmitted contains the slave address of the receiving device (7 bits) and the Read/Write (R/W) bit. In this case, the R/W bit will be logic '0'. Serial data is transmitted 8 bits at a time. After each byte is transmitted, an Acknowledge bit is received. START and STOP conditions are output to indicate the beginning and the end of a serial transfer. In Master Receive mode, the first byte transmitted contains the slave address of the transmitting device (7 bits) and the R/W bit. In this case, the R/W bit will be logic '1'. Thus, the first byte transmitted is a 7-bit slave address followed by a '1' to indicate receive bit. Serial data is received via SDA, while SCL outputs the serial clock. Serial data is received 8 bits at a time. After each byte is received, an Acknowledge bit is transmitted. START and STOP conditions indicate the beginning and end of transmission. The baud rate generator used for the SPI mode operation is used to set the SCL clock frequency for either 100 kHz, 400 kHz or 1 MHz I2C operation. See Section 17.4.7 ("Baud Rate Generator"), for more detail.
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17.4.7
2
BAUD RATE GENERATOR
In I C Master mode, the baud rate generator (BRG) reload value is placed in the lower 7 bits of the SSPADD register (Figure 17-17). When a write occurs to SSPBUF, the baud rate generator will automatically begin counting. The BRG counts down to `0' and stops until another reload has taken place. The BRG count is decremented twice per instruction cycle (TCY) on the Q2 and Q4 clocks. In I2C Master mode, the BRG is reloaded automatically.
Once the given operation is complete (i.e., transmission of the last data bit is followed by ACK), the internal clock will automatically stop counting and the SCL pin will remain in its last state. Table 15-3 demonstrates clock rates based on instruction cycles and the BRG value loaded into SSPADD.
FIGURE 17-17:
BAUD RATE GENERATOR BLOCK DIAGRAM
SSPM3:SSPM0 SSPADD<6:0>
SSPM3:SSPM0 SCL
Reload Control CLKO
Reload
BRG Down Counter
FOSC/4
TABLE 17-3:
FCY
I2C CLOCK RATE W/BRG
FCY*2 20 MHz 20 MHz 20 MHz 8 MHz 8 MHz 8 MHz 2 MHz 2 MHz 2 MHz BRG VALUE 19h 20h 3Fh 0Ah 0Dh 28h 03h 0Ah 00h FSCL (2 rollovers of BRG) 400 kHz(1) 312.5 kHz 100 kHz 400 kHz(1) 308 kHz 100 kHz 333 kHz(1) 100 kHz 1 MHz(1)
10 MHz 10 MHz 10 MHz 4 MHz 4 MHz 4 MHz 1 MHz 1 MHz 1 MHz
Note 1: The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than 100 kHz) in all details, but may be used with care where higher rates are required by the application.
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17.4.7.1 Clock Arbitration
Clock arbitration occurs when the master, during any receive, transmit or Repeated START/STOP condition, de-asserts the SCL pin (SCL allowed to float high). When the SCL pin is allowed to float high, the baud rate generator (BRG) is suspended from counting until the SCL pin is actually sampled high. When the SCL pin is sampled high, the baud rate generator is reloaded with the contents of SSPADD<6:0> and begins counting. This ensures that the SCL high time will always be at least one BRG rollover count, in the event that the clock is held low by an external device (Figure 15-18).
FIGURE 17-18:
SDA
BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION
DX DX-1 SCL allowed to transition high
SCL de-asserted but slave holds SCL low (clock arbitration) SCL BRG decrements on Q2 and Q4 cycles BRG Value 03h 02h 01h 00h (hold off)
03h
02h
SCL is sampled high, reload takes place and BRG starts its count BRG Reload
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17.4.8 I2C MASTER MODE START CONDITION TIMING 17.4.8.1 WCOL Status Flag
To initiate a START condition, the user sets the START condition enable bit, SEN (SSPCON2<0>). If the SDA and SCL pins are sampled high, the baud rate generator is reloaded with the contents of SSPADD<6:0> and starts its count. If SCL and SDA are both sampled high when the baud rate generator times out (TBRG), the SDA pin is driven low. The action of the SDA being driven low, while SCL is high, is the START condition and causes the S bit (SSPSTAT<3>) to be set. Following this, the baud rate generator is reloaded with the contents of SSPADD<6:0> and resumes its count. When the baud rate generator times out (TBRG), the SEN bit (SSPCON2<0>) will be automatically cleared by hardware, the baud rate generator is suspended, leaving the SDA line held low and the START condition is complete. Note: If at the beginning of the START condition, the SDA and SCL pins are already sampled low, or if during the START condition the SCL line is sampled low before the SDA line is driven low, a bus collision occurs, the Bus Collision Interrupt Flag, BCLIF is set, the START condition is aborted, and the I2C module is reset into its IDLE state. If the user writes the SSPBUF when a START sequence is in progress, the WCOL is set and the contents of the buffer are unchanged (the write doesn't occur). Note: Because queueing of events is not allowed, writing to the lower 5 bits of SSPCON2 is disabled until the START condition is complete.
FIGURE 17-19:
FIRST START BIT TIMING
Write to SEN bit occurs here Set S bit (SSPSTAT<3>) SDA = 1, SCL = 1 At completion of START bit, hardware clears SEN bit and sets SSPIF bit TBRG Write to SSPBUF occurs here 1st bit TBRG TBRG S 2nd bit
TBRG SDA
SCL
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17.4.9 I2C MASTER MODE REPEATED START CONDITION TIMING
A Repeated START condition occurs when the RSEN bit (SSPCON2<1>) is programmed high and the I2C logic module is in the IDLE state. When the RSEN bit is set, the SCL pin is asserted low. When the SCL pin is sampled low, the baud rate generator is loaded with the contents of SSPADD<5:0> and begins counting. The SDA pin is released (brought high) for one baud rate generator count (TBRG). When the baud rate generator times out, if SDA is sampled high, the SCL pin will be de-asserted (brought high). When SCL is sampled high, the baud rate generator is reloaded with the contents of SSPADD<6:0> and begins counting. SDA and SCL must be sampled high for one TBRG. This action is then followed by assertion of the SDA pin (SDA = 0) for one TBRG, while SCL is high. Following this, the RSEN bit (SSPCON2<1>) will be automatically cleared and the baud rate generator will not be reloaded, leaving the SDA pin held low. As soon as a START condition is detected on the SDA and SCL pins, the S bit (SSPSTAT<3>) will be set. The SSPIF bit will not be set until the baud rate generator has timed out. Note 1: If RSEN is programmed while any other event is in progress, it will not take effect. 2: A bus collision during the Repeated START condition occurs if: * SDA is sampled low when SCL goes from low to high. * SCL goes low before SDA is asserted low. This may indicate that another master is attempting to transmit a data "1". Immediately following the SSPIF bit getting set, the user may write the SSPBUF with the 7-bit address in 7-bit mode, or the default first address in 10-bit mode. After the first eight bits are transmitted and an ACK is received, the user may then transmit an additional eight bits of address (10-bit mode) or eight bits of data (7-bit mode).
17.4.9.1
WCOL Status Flag
If the user writes the SSPBUF when a Repeated START sequence is in progress, the WCOL is set and the contents of the buffer are unchanged (the write doesn't occur). Note: Because queueing of events is not allowed, writing of the lower 5 bits of SSPCON2 is disabled until the Repeated START condition is complete.
FIGURE 17-20:
REPEAT START CONDITION WAVEFORM
Write to SSPCON2 occurs here. SDA = 1, SCL (no change).
Set S (SSPSTAT<3>) SDA = 1, SCL = 1 At completion of START bit, hardware clears RSEN bit and sets SSPIF TBRG 1st bit Write to SSPBUF occurs here TBRG TBRG Sr = Repeated START
TBRG SDA Falling edge of ninth clock End of Xmit SCL
TBRG
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17.4.10 I2C MASTER MODE TRANSMISSION 17.4.10.3 ACKSTAT Status Flag
Transmission of a data byte, a 7-bit address, or the other half of a 10-bit address is accomplished by simply writing a value to the SSPBUF register. This action will set the buffer full flag bit, BF, and allow the baud rate generator to begin counting and start the next transmission. Each bit of address/data will be shifted out onto the SDA pin after the falling edge of SCL is asserted (see data hold time specification parameter #106). SCL is held low for one baud rate generator rollover count (TBRG). Data should be valid before SCL is released high (see data setup time specification parameter #107). When the SCL pin is released high, it is held that way for TBRG. The data on the SDA pin must remain stable for that duration and some hold time, after the next falling edge of SCL. After the eighth bit is shifted out (the falling edge of the eighth clock), the BF flag is cleared and the master releases SDA. This allows the slave device being addressed to respond with an ACK bit during the ninth bit time if an address match occurred, or if data was received properly. The status of ACK is written into the ACKDT bit on the falling edge of the ninth clock. If the master receives an Acknowledge, the Acknowledge status bit, ACKSTAT, is cleared. If not, the bit is set. After the ninth clock, the SSPIF bit is set and the master clock (baud rate generator) is suspended until the next data byte is loaded into the SSPBUF, leaving SCL low and SDA unchanged (Figure 17-21). After the write to the SSPBUF, each bit of address will be shifted out on the falling edge of SCL, until all seven address bits and the R/W bit are completed. On the falling edge of the eighth clock, the master will de-assert the SDA pin, allowing the slave to respond with an Acknowledge. On the falling edge of the ninth clock, the master will sample the SDA pin to see if the address was recognized by a slave. The status of the ACK bit is loaded into the ACKSTAT status bit (SSPCON2<6>). Following the falling edge of the ninth clock transmission of the address, the SSPIF is set, the BF flag is cleared and the baud rate generator is turned off until another write to the SSPBUF takes place, holding SCL low and allowing SDA to float. In Transmit mode, the ACKSTAT bit (SSPCON2<6>) is cleared when the slave has sent an Acknowledge (ACK = 0), and is set when the slave does not Acknowledge (ACK = 1). A slave sends an Acknowledge when it has recognized its address (including a general call), or when the slave has properly received its data.
17.4.11
I2C MASTER MODE RECEPTION
Master mode reception is enabled by programming the receive enable bit, RCEN (SSPCON2<3>). Note: The MSSP module must be in an IDLE state before the RCEN bit is set, or the RCEN bit will be disregarded.
The baud rate generator begins counting, and on each rollover, the state of the SCL pin changes (high to low/low to high) and data is shifted into the SSPSR. After the falling edge of the eighth clock, the receive enable flag is automatically cleared, the contents of the SSPSR are loaded into the SSPBUF, the BF flag bit is set, the SSPIF flag bit is set and the baud rate generator is suspended from counting, holding SCL low. The MSSP is now in IDLE state, awaiting the next command. When the buffer is read by the CPU, the BF flag bit is automatically cleared. The user can then send an Acknowledge bit at the end of reception, by setting the Acknowledge sequence enable bit, ACKEN (SSPCON2<4>).
17.4.11.1
BF Status Flag
In receive operation, the BF bit is set when an address or data byte is loaded into SSPBUF from SSPSR. It is cleared when the SSPBUF register is read.
17.4.11.2
SSPOV Status Flag
In receive operation, the SSPOV bit is set when 8 bits are received into the SSPSR and the BF flag bit is already set from a previous reception.
17.4.11.3
WCOL Status Flag
17.4.10.1
BF Status Flag
If the user writes the SSPBUF when a receive is already in progress (i.e., SSPSR is still shifting in a data byte), the WCOL bit is set and the contents of the buffer are unchanged (the write doesn't occur).
In Transmit mode, the BF bit (SSPSTAT<0>) is set when the CPU writes to SSPBUF and is cleared when all 8 bits are shifted out.
17.4.10.2
WCOL Status Flag
If the user writes the SSPBUF when a transmit is already in progress (i.e., SSPSR is still shifting out a data byte), the WCOL is set and the contents of the buffer are unchanged (the write doesn't occur). WCOL must be cleared in software.
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FIGURE 17-21:
DS39609A-page 188
Write SSPCON2<0> SEN = 1 START condition begins From slave clear ACKSTAT bit SSPCON2<6> R/W = 0 A1 ACK = 0 D7 D6 D5 D4 D3 D2 D1 Transmitting Data or Second Half of 10-bit Address D0 ACK SEN = 0 Transmit Address to Slave SDA A7 SSPBUF written with 7-bit address and R/W start transmit SCL S 1 2 3 4 5 6 7 8 9 1 SCL held low while CPU responds to SSPIF 2 3 4 5 6 7 8 9 P A6 A5 A4 A3 A2 ACKSTAT in SSPCON2 = 1 SSPIF Cleared in software Cleared in software service routine From SSP interrupt Cleared in software BF (SSPSTAT<0>) SSPBUF written SEN After START condition, SEN cleared by hardware SSPBUF is written in software PEN
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I 2C MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS)
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R/W
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FIGURE 17-22:
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Write to SSPCON2<4> to start Acknowledge sequence SDA = ACKDT (SSPCON2<5>) = 0 Master configured as a receiver by programming SSPCON2<3> (RCEN = 1) ACK from Slave R/W = 1 Receiving Data from Slave ACK Receiving Data from Slave RCEN cleared automatically RCEN = 1 Start next receive RCEN cleared automatically ACK ACK from Master SDA = ACKDT = 0 Set ACKEN, start Acknowledge sequence SDA = ACKDT = 1 PEN bit = 1 written here
Write to SSPCON2<0> (SEN = 1) Begin START Condition
SEN = 0 Write to SSPBUF occurs here Start XMIT
Transmit Address to Slave
SDA D0
A7 A1 D7 D6 D5 D4 D3 D2 D1 D7 D6 D5 D4 D3 D2 D1
A6 A5 A4 A3 A2
D0
ACK ACK is not sent Bus Master terminates transfer
SCL
Set SSPIF interrupt at end of receive
S
1 5 1 2 3 4 5 1 2 3 4
2
3 4 8 6 7 8 9
6
7 9
5
6
7
8
9
Set SSPIF at end of receive
P
Set SSPIF interrupt at end of Acknowledge sequence
Data shifted in on falling edge of CLK
SSPIF
Cleared in software Cleared in software
Set SSPIF interrupt at end of Acknowledge sequence Cleared in software Cleared in software
I 2C MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)
Advance Information
Last bit is shifted into SSPSR and contents are unloaded into SSPBUF
SDA = 0, SCL = 1 while CPU responds to SSPIF
Cleared in software
Set P bit (SSPSTAT<4>) and SSPIF
BF (SSPSTAT<0>)
SSPOV
SSPOV is set because SSPBUF is still full
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ACKEN
DS39609A-page 189
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17.4.12 ACKNOWLEDGE SEQUENCE TIMING 17.4.13 STOP CONDITION TIMING
An Acknowledge sequence is enabled by setting the Acknowledge sequence enable bit, ACKEN (SSPCON2<4>). When this bit is set, the SCL pin is pulled low and the contents of the Acknowledge data bit are presented on the SDA pin. If the user wishes to generate an Acknowledge, then the ACKDT bit should be cleared. If not, the user should set the ACKDT bit before starting an Acknowledge sequence. The baud rate generator then counts for one rollover period (TBRG) and the SCL pin is de-asserted (pulled high). When the SCL pin is sampled high (clock arbitration), the baud rate generator counts for TBRG. The SCL pin is then pulled low. Following this, the ACKEN bit is automatically cleared, the baud rate generator is turned off and the MSSP module then goes into IDLE mode (Figure 17-23). A STOP bit is asserted on the SDA pin at the end of a receive/transmit by setting the STOP sequence enable bit, PEN (SSPCON2<2>). At the end of a receive/transmit, the SCL line is held low after the falling edge of the ninth clock. When the PEN bit is set, the master will assert the SDA line low. When the SDA line is sampled low, the baud rate generator is reloaded and counts down to `0'. When the baud rate generator times out, the SCL pin will be brought high, and one TBRG (baud rate generator rollover count) later, the SDA pin will be de-asserted. When the SDA pin is sampled high while SCL is high, the P bit (SSPSTAT<4>) is set. A TBRG later, the PEN bit is cleared and the SSPIF bit is set (Figure 17-24).
17.4.13.1
WCOL Status Flag
17.4.12.1
WCOL Status Flag
If the user writes the SSPBUF when an Acknowledge sequence is in progress, then WCOL is set and the contents of the buffer are unchanged (the write doesn't occur).
If the user writes the SSPBUF when a STOP sequence is in progress, then the WCOL bit is set and the contents of the buffer are unchanged (the write doesn't occur).
FIGURE 17-23:
ACKNOWLEDGE SEQUENCE WAVEFORM
Acknowledge sequence starts here, Write to SSPCON2 ACKEN = 1, ACKDT = 0 TBRG SDA SCL D0 8 ACK TBRG ACKEN automatically cleared
9
SSPIF Cleared in software Set SSPIF at the end of Acknowledge sequence
Set SSPIF at the end of receive Note: TBRG = one baud rate generator period.
Cleared in software
FIGURE 17-24:
STOP CONDITION RECEIVE OR TRANSMIT MODE
Write to SSPCON2 Set PEN SCL = 1 for TBRG, followed by SDA = 1 for TBRG after SDA sampled high. P bit (SSPSTAT<4>) is set. PEN bit (SSPCON2<2>) is cleared by hardware and the SSPIF bit is set TBRG
Falling edge of 9th clock SCL
SDA
ACK P TBRG TBRG TBRG SCL brought high after TBRG SDA asserted low before rising edge of clock to setup STOP condition
Note: TBRG = one baud rate generator period.
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17.4.14 SLEEP OPERATION
2
17.4.17
While in SLEEP mode, the I C module can receive addresses or data, and when an address match or complete byte transfer occurs, wake the processor from SLEEP (if the MSSP interrupt is enabled).
MULTI -MASTER COMMUNICATION, BUS COLLISION, AND BUS ARBITRATION
17.4.15
EFFECT OF A RESET
A RESET disables the MSSP module and terminates the current transfer.
17.4.16
MULTI-MASTER MODE
In Multi-Master mode, the interrupt generation on the detection of the START and STOP conditions allows the determination of when the bus is free. The STOP (P) and START (S) bits are cleared from a RESET or when the MSSP module is disabled. Control of the I 2C bus may be taken when the P bit (SSPSTAT<4>) is set, or the bus is idle with both the S and P bits clear. When the bus is busy, enabling the SSP interrupt will generate the interrupt when the STOP condition occurs. In multi-master operation, the SDA line must be monitored for arbitration, to see if the signal level is the expected output level. This check is performed in hardware, with the result placed in the BCLIF bit. The states where arbitration can be lost are: * * * * * Address Transfer Data Transfer A START Condition A Repeated START Condition An Acknowledge Condition
Multi-Master mode support is achieved by bus arbitration. When the master outputs address/data bits onto the SDA pin, arbitration takes place when the master outputs a '1' on SDA, by letting SDA float high and another master asserts a '0'. When the SCL pin floats high, data should be stable. If the expected data on SDA is a '1' and the data sampled on the SDA pin = 0, then a bus collision has taken place. The master will set the Bus Collision Interrupt Flag, BCLIF and reset the I2C port to its IDLE state (Figure 17-25). If a transmit was in progress when the bus collision occurred, the transmission is halted, the BF flag is cleared, the SDA and SCL lines are de-asserted, and the SSPBUF can be written to. When the user services the bus collision Interrupt Service Routine, and if the I2C bus is free, the user can resume communication by asserting a START condition. If a START, Repeated START, STOP, or Acknowledge condition was in progress when the bus collision occurred, the condition is aborted, the SDA and SCL lines are de-asserted, and the respective control bits in the SSPCON2 register are cleared. When the user services the bus collision Interrupt Service Routine, and if the I2C bus is free, the user can resume communication by asserting a START condition. The master will continue to monitor the SDA and SCL pins. If a STOP condition occurs, the SSPIF bit will be set. A write to the SSPBUF will start the transmission of data at the first data bit, regardless of where the transmitter left off when the bus collision occurred. In Multi-Master mode, the interrupt generation on the detection of START and STOP conditions allows the determination of when the bus is free. Control of the I2C bus can be taken when the P bit is set in the SSPSTAT register, or the bus is IDLE and the S and P bits are cleared.
FIGURE 17-25:
BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE
Data changes while SCL = 0 SDA line pulled low by another source SDA released by master Sample SDA. While SCL is high, data doesn't match what is driven by the master. Bus collision has occurred.
SDA
SCL
Set bus collision interrupt (BCLIF)
BCLIF
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17.4.17.1 Bus Collision During a START Condition
During a START condition, a bus collision occurs if: a) b) SDA or SCL are sampled low at the beginning of the START condition (Figure 17-26). SCL is sampled low before SDA is asserted low (Figure 17-27). If the SDA pin is sampled low during this count, the BRG is reset and the SDA line is asserted early (Figure 17-28). If, however, a '1' is sampled on the SDA pin, the SDA pin is asserted low at the end of the BRG count. The baud rate generator is then reloaded and counts down to `0', and during this time, if the SCL pins are sampled as '0', a bus collision does not occur. At the end of the BRG count, the SCL pin is asserted low. Note: The reason that bus collision is not a factor during a START condition is that no two bus masters can assert a START condition at the exact same time. Therefore, one master will always assert SDA before the other. This condition does not cause a bus collision, because the two masters must be allowed to arbitrate the first address following the START condition. If the address is the same, arbitration must be allowed to continue into the data portion, Repeated START or STOP conditions.
During a START condition, both the SDA and the SCL pins are monitored. If the SDA pin is already low, or the SCL pin is already low, then all of the following occur: * the START condition is aborted, * the BCLIF flag is set, and * the MSSP module is reset to its IDLE state (Figure 17-26). The START condition begins with the SDA and SCL pins de-asserted. When the SDA pin is sampled high, the baud rate generator is loaded from SSPADD<6:0> and counts down to `0'. If the SCL pin is sampled low while SDA is high, a bus collision occurs, because it is assumed that another master is attempting to drive a data '1' during the START condition.
FIGURE 17-26:
BUS COLLISION DURING START CONDITION (SDA ONLY)
SDA goes low before the SEN bit is set. Set BCLIF, S bit and SSPIF set because SDA = 0, SCL = 1.
SDA
SCL Set SEN, enable START condition if SDA = 1, SCL = 1 SEN SDA sampled low before START condition. Set BCLIF. S bit and SSPIF set because SDA = 0, SCL = 1. SSPIF and BCLIF are cleared in software S SEN cleared automatically because of bus collision. SSP module reset into IDLE state.
BCLIF
SSPIF SSPIF and BCLIF are cleared in software
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FIGURE 17-27: BUS COLLISION DURING START CONDITION (SCL = 0)
SDA = 0, SCL = 1
TBRG TBRG
SDA Set SEN, enable START sequence if SDA = 1, SCL = 1 SCL = 0 before SDA = 0, bus collision occurs. Set BCLIF. SCL = 0 before BRG time-out, bus collision occurs. Set BCLIF. BCLIF Interrupt cleared in software S SSPIF '0' '0' '0' '0'
SCL
SEN
FIGURE 17-28:
BRG RESET DUE TO SDA ARBITRATION DURING START CONDITION
SDA = 0, SCL = 1 Set S Less than TBRG
TBRG
Set SSPIF
SDA
SDA pulled low by other master. Reset BRG and assert SDA.
SCL
S
SCL pulled low after BRG Time-out Set SEN, enable START sequence if SDA = 1, SCL = 1
SEN
BCLIF
'0'
S
SSPIF SDA = 0, SCL = 1 Set SSPIF Interrupts cleared in software
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17.4.17.2 Bus Collision During a Repeated START Condition
During a Repeated START condition, a bus collision occurs if: a) b) A low level is sampled on SDA when SCL goes from low level to high level. SCL goes low before SDA is asserted low, indicating that another master is attempting to transmit a data '1'. reloaded and begins counting. If SDA goes from high to low before the BRG times out, no bus collision occurs because no two masters can assert SDA at exactly the same time. If SCL goes from high to low before the BRG times out and SDA has not already been asserted, a bus collision occurs. In this case, another master is attempting to transmit a data '1' during the Repeated START condition, Figure 17-30. If, at the end of the BRG time-out, both SCL and SDA are still high, the SDA pin is driven low and the BRG is reloaded and begins counting. At the end of the count, regardless of the status of the SCL pin, the SCL pin is driven low and the Repeated START condition is complete.
When the user de-asserts SDA and the pin is allowed to float high, the BRG is loaded with SSPADD<6:0> and counts down to `0'. The SCL pin is then de-asserted, and when sampled high, the SDA pin is sampled. If SDA is low, a bus collision has occurred (i.e., another master is attempting to transmit a data '0', Figure 17-29). If SDA is sampled high, the BRG is
FIGURE 17-29:
SDA SCL
BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)
Sample SDA when SCL goes high. If SDA = 0, set BCLIF and release SDA and SCL. RSEN BCLIF Cleared in software '0' '0'
S SSPIF
FIGURE 17-30:
BUS COLLISION DURING REPEATED START CONDITION (CASE 2)
TBRG TBRG
SDA SCL BCLIF SCL goes low before SDA, Set BCLIF. Release SDA and SCL. Interrupt cleared in software RSEN S SSPIF
'0'
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17.4.17.3 Bus Collision During a STOP Condition
Bus collision occurs during a STOP condition if: a) After the SDA pin has been de-asserted and allowed to float high, SDA is sampled low after the BRG has timed out. After the SCL pin is de-asserted, SCL is sampled low before SDA goes high. The STOP condition begins with SDA asserted low. When SDA is sampled low, the SCL pin is allowed to float. When the pin is sampled high (clock arbitration), the baud rate generator is loaded with SSPADD<6:0> and counts down to `0'. After the BRG times out, SDA is sampled. If SDA is sampled low, a bus collision has occurred. This is due to another master attempting to drive a data '0' (Figure 17-31). If the SCL pin is sampled low before SDA is allowed to float high, a bus collision occurs. This is another case of another master attempting to drive a data '0' (Figure 17-32).
b)
FIGURE 17-31:
BUS COLLISION DURING A STOP CONDITION (CASE 1)
TBRG TBRG TBRG
SDA sampled low after TBRG, set BCLIF
SDA SDA asserted low SCL PEN BCLIF P SSPIF
'0' '0'
FIGURE 17-32:
BUS COLLISION DURING A STOP CONDITION (CASE 2)
TBRG TBRG TBRG
SDA Assert SDA SCL PEN BCLIF P SSPIF '0' '0' SCL goes low before SDA goes high, set BCLIF
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NOTES:
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18.0 ADDRESSABLE UNIVERSAL SYNCHRONOUS ASYNCHRONOUS RECEIVER TRANSMITTER (USART)
Register 18-1 shows the layout of the Transmit Status and Control Registers (TXSTAx) and Register 18-2 shows the layout of the Receive Status and Control Registers (RCSTAx). USART1 and USART2 each have their own independent and distinct pairs of transmit and receive control registers, which are identical to each other apart from their names. Similarly, each USART has its own distinct set of transmit, receive and baud rate registers. Note: Throughout this section, references to register and bit names that may be associated with a specific USART module are referred to generically by the use of `x' in place of the specific module number. Thus, "RCSTAx" might refer to the receive status register for either USART1 or USART2.
The Universal Synchronous Asynchronous Receiver Transmitter (USART) module (also known as a Serial Communications Interface or SCI) is one of the two types of serial I/O modules available on PIC18FXX20 devices. Each device has two USARTs, which can be configured independently of each other. Each can be configured as a full-duplex asynchronous system that can communicate with peripheral devices, such as CRT terminals and personal computers, or as a half-duplex synchronous system that can communicate with peripheral devices, such as A/D or D/A integrated circuits, serial EEPROMs, etc. The USART can be configured in the following modes: * Asynchronous (full-duplex) * Synchronous - Master (half-duplex) * Synchronous - Slave (half-duplex) The pins of USART1 and USART2 are multiplexed with the functions of PORTC (RC6/TX1/CK1 and RC7/RX1/DT1) and PORTG (RG1/TX2/CK2 and RG2/RX2/DT2), respectively. In order to configure these pins as a USART: * For USART1: - bit SPEN (RCSTA1<7>) must be set (= 1) - bit TRISC<7> must be set (= 1) - bit TRISC<6> must be cleared (= 0) for Asynchronous and Synchronous Master modes - bit TRISC<6> must be set (= 1) for Synchronous Slave mode * For USART2: - bit SPEN (RCSTA2<7>) must be set (= 1) - bit TRISG<2> must be set (= 1) - bit TRISG<1> must be cleared (= 0) for Asynchronous and Synchronous Master modes - bit TRISC<6> must be set (= 1) for Synchronous Slave mode
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REGISTER 18-1: TXSTAx: TRANSMIT STATUS AND CONTROL REGISTER
R/W-0 CSRC bit 7 bit 7 R/W-0 TX9 R/W-0 TXEN R/W-0 SYNC U-0 -- R/W-0 BRGH R-1 TRMT R/W-0 TX9D bit 0
CSRC: Clock Source Select bit Asynchronous mode: Don't care Synchronous mode: 1 = Master mode (clock generated internally from BRG) 0 = Slave mode (clock from external source) TX9: 9-bit Transmit Enable bit 1 = Selects 9-bit transmission 0 = Selects 8-bit transmission TXEN: Transmit Enable bit 1 = Transmit enabled 0 = Transmit disabled Note: SREN/CREN overrides TXEN in Sync mode.
bit 6
bit 5
bit 4
SYNC: USART Mode Select bit 1 = Synchronous mode 0 = Asynchronous mode Unimplemented: Read as '0' BRGH: High Baud Rate Select bit Asynchronous mode: 1 = High speed 0 = Low speed Synchronous mode: Unused in this mode TRMT: Transmit Shift Register Status bit 1 = TSR empty 0 = TSR full TX9D: 9th bit of Transmit Data Can be address/data bit or a parity bit Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 3 bit 2
bit 1
bit 0
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REGISTER 18-2: RCSTAx: RECEIVE STATUS AND CONTROL REGISTER
R/W-0 SPEN bit 7 bit 7 R/W-0 RX9 R/W-0 SREN R/W-0 CREN R/W-0 ADDEN R-0 FERR R-0 OERR R-x RX9D bit 0
SPEN: Serial Port Enable bit 1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins) 0 = Serial port disabled RX9: 9-bit Receive Enable bit 1 = Selects 9-bit reception 0 = Selects 8-bit reception SREN: Single Receive Enable bit Asynchronous mode: Don't care Synchronous mode - Master: 1 = Enables single receive 0 = Disables single receive This bit is cleared after reception is complete. Synchronous mode - Slave: Don't care CREN: Continuous Receive Enable bit Asynchronous mode: 1 = Enables receiver 0 = Disables receiver Synchronous mode: 1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN) 0 = Disables continuous receive ADDEN: Address Detect Enable bit Asynchronous mode 9-bit (RX9 = 1): 1 = Enables address detection, enables interrupt and load of the receive buffer when RSR<8> is set 0 = Disables address detection, all bytes are received, and ninth bit can be used as parity bit FERR: Framing Error bit 1 = Framing error (can be updated by reading RCREG register and receive next valid byte) 0 = No framing error OERR: Overrun Error bit 1 = Overrun error (can be cleared by clearing bit CREN) 0 = No overrun error RX9D: 9th bit of Received Data This can be address/data bit or a parity bit, and must be calculated by user firmware Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
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18.1 USART Baud Rate Generator (BRG)
Example 18-1 shows the calculation of the baud rate error for the following conditions: * * * * FOSC = 16 MHz Desired Baud Rate = 9600 BRGH = 0 SYNC = 0
The BRG supports both the Asynchronous and Synchronous modes of the USARTs. It is a dedicated 8-bit baud rate generator. The SPBRG register controls the period of a free running 8-bit timer. In Asynchronous mode, bit BRGH (TXSTAx<2>) also controls the baud rate. In Synchronous mode, bit BRGH is ignored. Table 18-1 shows the formula for computation of the baud rate for different USART modes, which only apply in Master mode (internal clock). Given the desired baud rate and FOSC, the nearest integer value for the SPBRGx register can be calculated using the formula in Table 18-1. From this, the error in baud rate can be determined.
It may be advantageous to use the high baud rate (BRGH = 1), even for slower baud clocks. This is because the equation in Example 18-1 can reduce the baud rate error in some cases. Writing a new value to the SPBRGx register causes the BRG timer to be reset (or cleared). This ensures the BRG does not wait for a timer overflow before outputting the new baud rate.
18.1.1
SAMPLING
The data on the RXx pin (either RC7/RX1/DT1 or RG2/RX2/DT2) is sampled three times by a majority detect circuit to determine if a high or a low level is present at the pin.
EXAMPLE 18-1:
Desired Baud Rate Solving for X: X X X Calculated Baud Rate Error
CALCULATING BAUD RATE ERROR
= FOSC / (64 (X + 1)) = ( (FOSC / Desired Baud Rate) / 64 ) - 1 = ((16000000 / 9600) / 64) - 1 = [25.042] = 25 = = = = = 16000000 / (64 (25 + 1)) 9615 (Calculated Baud Rate - Desired Baud Rate) Desired Baud Rate (9615 - 9600) / 9600 0.16%
TABLE 18-1:
SYNC
BAUD RATE FORMULA
BRGH = 0 (Low Speed) BRGH = 1 (High Speed) Baud Rate = FOSC/(16(X+1)) N/A
0 (Asynchronous) Baud Rate = FOSC/(64(X+1)) (Synchronous) Baud Rate = FOSC/(4(X+1)) 1 Legend: X = value in SPBRGx (0 to 255)
TABLE 18-2:
Name
REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other RESETS
Bit 7
CSRC TX9 TXEN SYNC -- BRGH TRMT TX9D 0000 -010 0000 -010 TXSTAx RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x SPBRGx Baud Rate Generator Register 0000 0000 0000 0000 Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used by the BRG. Note: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
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TABLE 18-3:
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
BAUD RATES FOR SYNCHRONOUS MODE
FOSC = 40 MHz % ERROR +0.16 +0.16 +1.01 0 FOSC = 16 MHz % ERROR +0.16 +0.16 -0.79 +2.56 0 FOSC = 4 MHz % ERROR +0.16 +0.16 +0.16 +4.17 +11.11 0 SPBRG value (decimal) 103 51 12 9 2 1 0 255 SPBRG value (decimal) 207 51 41 12 7 0 255 SPBRG value (decimal) 129 103 32 19 0 255 33 MHz % ERROR +0.39 -0.07 -1.79 -2.94 10 MHz % ERROR +0.16 -1.36 +0.16 +4.17 0 3.579545 MHz % ERROR +0.23 -0.83 -2.90 +3.57 -0.57 -10.51 SPBRG value (decimal) 92 46 11 8 2 1 0 255 SPBRG value (decimal) 129 32 25 7 4 0 255 SPBRG value (decimal) 106 85 27 16 0 255 25 MHz % ERROR +0.47 +0.16 -0.79 -3.85 7.15909 MHz % ERROR +0.23 +0.23 +1.32 -1.88 -0.57 -10.51 1 MHz % ERROR +0.16 +0.16 +0.16 +0.16 +8.51 -13.19 -16.67 SPBRG value (decimal) 207 103 25 12 2 2 0 0 255 SPBRG value (decimal) 185 92 22 18 5 3 0 255 SPBRG value (decimal) 80 64 20 12 0 255 20 MHz % ERROR +0.16 +0.16 -1.96 0 5.0688 MHz % ERROR 0 0 -2.94 +1.54 +5.60 -15.52 32.768 kHz % ERROR +1.14 -2.48 +13.78 -14.67 SPBRG value (decimal) 26 6 2 0 0 255 SPBRG value (decimal) 131 65 16 12 3 2 0 255 SPBRG value (decimal) 64 51 16 9 0 255
KBAUD NA NA NA NA NA 76.92 96.15 303.03 500 10000 39.06
KBAUD NA NA NA NA NA 77.10 95.93 294.64 485.30 8250 32.23
KBAUD NA NA NA NA NA 77.16 96.15 297.62 480.77 6250 24.41
KBAUD NA NA NA NA NA 76.92 96.15 294.12 500 5000 19.53
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
KBAUD NA NA NA NA 19.23 76.92 95.24 307.70 500 4000 15.63
KBAUD NA NA NA NA 19.23 75.76 96.15 312.50 500 2500 9.77
KBAUD NA NA NA 9.62 19.24 77.82 94.20 298.35 447.44 1789.80 6.99
KBAUD NA NA NA 9.60 19.20 74.54 97.48 316.80 422.40 1267.20 4.95
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
KBAUD NA NA NA 9.62 19.23 76.92 1000 333.33 500 1000 3.91
KBAUD NA NA NA 9.62 19.04 74.57 99.43 298.30 447.44 894.89 3.50
KBAUD NA 1.20 2.40 9.62 19.23 83.33 83.33 250 NA 250 0.98
KBAUD 0.30 1.17 2.73 8.20 NA NA NA NA NA 8.20 0.03
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TABLE 18-4:
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 0)
FOSC = 40 MHz % ERROR +0.16 -1.36 +1.73 -6.99 +4.17 +25.00 FOSC = 16 MHz % ERROR +0.16 +0.16 +0.16 +0.16 +8.51 -13.19 -16.67 FOSC = 4 MHz % ERROR -0.16 +1.67 +1.67 -6.99 +8.51 -18.62 SPBRG value (decimal) 207 51 25 6 2 0 0 255 SPBRG value (decimal) 207 103 25 12 2 2 0 0 255 SPBRG value (decimal) 64 32 7 6 1 0 0 255 33 MHz % ERROR -0.07 -0.54 -0.54 -4.09 +7.42 -14.06 10 MHz % ERROR +0.16 +0.16 +1.73 +1.73 +1.73 -18.62 -47.92 3.579545 MHz % ERROR +0.23 -0.83 +1.32 -2.90 -2.90 -27.17 SPBRG value (decimal) 185 46 22 5 2 0 0 255 SPBRG value (decimal) 129 64 15 7 1 1 0 0 255 SPBRG value (decimal) 214 53 26 6 4 1 0 255 25 MHz % ERROR -0.15 -0.76 +1.73 +1.73 +1.73 7.15909 MHz % ERROR +0.23 -0.83 -2.90 -2.90 +45.65 1 MHz % ERROR +0.16 +0.16 -6.99 -18.62 -18.62 SPBRG value (decimal) 51 12 6 1 0 0 255 SPBRG value (decimal) 92 46 11 5 0 0 255 SPBRG value (decimal) 162 40 19 4 3 0 255 20 MHz % ERROR +0.16 -1.36 +1.73 +1.73 +8.51 +4.17 5.0688 MHz % ERROR 0 0 +3.13 +3.13 +3.13 32.768 kHz % ERROR -14.67 SPBRG value (decimal) 1 0 255 SPBRG value (decimal) 65 32 7 3 0 0 255 SPBRG value (decimal) 129 32 15 3 2 0 0 255
KBAUD NA NA NA 9.62 18.94 78.13 89.29 312.50 625 625 2.44
KBAUD NA NA 2.40 9.55 19.10 73.66 103.13 257.81 NA 515.63 2.01
KBAUD NA NA 2.40 9.53 19.53 78.13 97.66 NA NA 390.63 1.53
KBAUD NA NA 2.40 9.47 19.53 78.13 104.17 312.50 NA 312.50 1.22
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
KBAUD NA 1.20 2.40 9.62 19.23 83.33 83.33 250 NA 250 0.98
KBAUD NA 1.20 2.40 9.77 19.53 78.13 78.13 156.25 NA 156.25 0.61
KBAUD NA 1.20 2.38 9.32 18.64 111.86 NA NA NA 111.86 0.44
KBAUD NA 1.20 2.40 9.90 19.80 79.20 NA NA NA 79.20 0.31
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
KBAUD 0.30 1.20 2.40 8.93 20.83 62.50 NA NA NA 62.50 0.24
KBAUD 0.30 1.19 2.43 9.32 18.64 55.93 NA NA NA 55.93 0.22
KBAUD 0.30 1.20 2.23 7.81 15.63 NA NA NA NA 15.63 0.06
KBAUD 0.26 NA NA NA NA NA NA NA NA 0.51 0.002
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TABLE 18-5:
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 1)
FOSC = 40 MHz % ERROR +0.16 -1.36 +0.16 +4.17 0 FOSC = 16 MHz % ERROR +0.16 +0.16 +0.16 +4.17 +11.11 0 FOSC = 4 MHz % ERROR +0.16 +0.16 +0.16 +0.16 SPBRG value (decimal) 207 103 25 12 0 255 SPBRG value (decimal) 103 51 12 9 2 1 0 255 SPBRG value (decimal) 129 32 25 7 4 0 255 33 MHz % ERROR -0.07 +0.39 -0.54 +2.31 -1.79 +3.13 10 MHz % ERROR +0.16 -1.36 +1.73 -6.99 +4.17 +25.00 3.579545 MHz % ERROR +0.23 +0.23 +1.32 -2.90 -2.90 +16.52 -25.43 SPBRG value (decimal) 185 92 22 11 2 1 0 0 255 SPBRG value (decimal) 64 32 7 6 1 0 0 255 SPBRG value (decimal) 214 106 26 20 6 3 0 255 25 MHz % ERROR -0.15 +0.47 +1.73 +1.73 +4.17 +4.17 7.15909 MHz % ERROR +0.23 -0.83 +1.32 -2.90 -6.78 +49.15 -10.51 1 MHz % ERROR +0.16 +0.16 +0.16 -6.99 +8.51 -18.62 SPBRG value (decimal) 207 51 25 6 2 0 0 255 SPBRG value (decimal) 185 46 22 5 4 0 0 0 255 SPBRG value (decimal) 162 80 19 15 4 2 0 255 20 MHz % ERROR +0.16 +0.16 +1.73 +0.16 +4.17 -16.67 5.0688 MHz % ERROR 0 0 -2.94 +3.13 +10.00 +5.60 32.768 kHz % ERROR -2.48 -14.67 -14.67 SPBRG value (decimal) 6 1 0 0 255 SPBRG value (decimal) 131 32 16 3 2 0 0 255 SPBRG value (decimal) 129 64 15 12 3 2 0 255
KBAUD NA NA NA NA 19.23 75.76 96.15 312.50 500 2500 9.77
KBAUD NA NA NA 9.60 19.28 76.39 98.21 294.64 515.63 2062.50 8,06
KBAUD NA NA NA 9.59 19.30 78.13 97.66 312.50 520.83 1562.50 6.10
KBAUD NA NA NA 9.62 19.23 78.13 96.15 312.50 416.67 1250 4.88
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
KBAUD NA NA NA 9.62 19.23 76.92 100 333.33 500 1000 3.91
KBAUD NA NA NA 9.62 18.94 78.13 89.29 312.50 625 625 2.44
KBAUD NA NA 2.41 9.52 19.45 74.57 89.49 447.44 447.44 447.44 1.75
KBAUD NA NA 2.40 9.60 18.64 79.20 105.60 316.80 NA 316.80 1.24
BAUD RATE (Kbps) 0.3 1.2 2.4 9.6 19.2 76.8 96 300 500 HIGH LOW
KBAUD NA 1.20 2.40 9.62 19.23 NA NA NA NA 250 0.98
KBAUD NA 1.20 2.41 9.73 18.64 74.57 111.86 223.72 NA 55.93 0.22
KBAUD 0.30 1.20 2.40 8.93 20.83 62.50 NA NA NA 62.50 0.24
KBAUD 0.29 1.02 2.05 NA NA NA NA NA NA 2.05 0.008
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18.2 USART Asynchronous Mode
In this mode, the USARTs use standard non-return-to-zero (NRZ) format (one START bit, eight or nine data bits and one STOP bit). The most common data format is 8 bits. An on-chip dedicated 8-bit baud rate generator can be used to derive standard baud rate frequencies from the oscillator. The USART transmits and receives the LSbit first. The USART's transmitter and receiver are functionally independent, but use the same data format and baud rate. The baud rate generator produces a clock, either 16 or 64 times the bit shift rate, depending on bit BRGH (TXSTAx<2>). Parity is not supported by the hardware, but can be implemented in software (and stored as the ninth data bit). Asynchronous mode is stopped during SLEEP. Asynchronous mode is selected by clearing bit SYNC (TXSTAx<4>). The USART Asynchronous module consists of the following important elements: * * * * Baud Rate Generator Sampling Circuit Asynchronous Transmitter Asynchronous Receiver USART2), is set. This interrupt can be enabled/disabled by setting/clearing enable bit, TXxIE (PIE1<4> for USART1, PIE<4> for USART2). Flag bit TXxIF will be set, regardless of the state of enable bit TXxIE and cannot be cleared in software. It will reset only when new data is loaded into the TXREGx register. While flag bit TXIF indicated the status of the TXREGx register, another bit, TRMT (TXSTAx<1>), shows the status of the TSR register. Status bit TRMT is a read only bit, which is set when the TSR register is empty. No interrupt logic is tied to this bit, so the user has to poll this bit in order to determine if the TSR register is empty. Note 1: The TSR register is not mapped in data memory, so it is not available to the user. 2: Flag bit TXIF is set when enable bit TXEN is set. To set up an asynchronous transmission: 1. Initialize the SPBRGx register for the appropriate baud rate. If a high speed baud rate is desired, set bit BRGH (Section 18.1). Enable the asynchronous serial port by clearing bit SYNC and setting bit SPEN. If interrupts are desired, set enable bit TXxIE in the appropriate PIE register. If 9-bit transmission is desired, set transmit bit TX9. Can be used as address/data bit. Enable the transmission by setting bit TXEN, which will also set bit TXxIF. If 9-bit transmission is selected, the ninth bit should be loaded in bit TX9D. Load data to the TXREGx register (starts transmission). Note: TXIF is not cleared immediately upon loading data into the transmit buffer TXREG. The flag bit becomes valid in the second instruction cycle following the load instruction.
2. 3. 4. 5. 6. 7.
18.2.1
USART ASYNCHRONOUS TRANSMITTER
The USART transmitter block diagram is shown in Figure 18-1. The heart of the transmitter is the Transmit (serial) Shift Register (TSR). The shift register obtains its data from the read/write transmit buffer, TXREGx. The TXREGx register is loaded with data in software. The TSR register is not loaded until the STOP bit has been transmitted from the previous load. As soon as the STOP bit is transmitted, the TSR is loaded with new data from the TXREGx register (if available). Once the TXREGx register transfers the data to the TSR register (occurs in one TCY), the TXREGx register is empty and flag bit, TXx1IF (PIR1<4> for USART1, PIR3<4> for
FIGURE 18-1:
USART TRANSMIT BLOCK DIAGRAM
Data Bus TXIF TXREG Register 8 MSb (8) Interrupt TXEN Baud Rate CLK TRMT SPBRG Baud Rate Generator TX9 TX9D SPEN *** TSR Register LSb 0 Pin Buffer and Control TX pin
TXIE
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FIGURE 18-2:
Write to TXREG BRG Output (Shift Clock) RC6/TX1/CK1 (pin) TXIF bit (Transmit Buffer Reg. Empty Flag)
ASYNCHRONOUS TRANSMISSION
Word 1
START bit
bit 0
bit 1 Word 1
bit 7/8
STOP bit
TRMT bit (Transmit Shift Reg. Empty Flag)
Word 1 Transmit Shift Reg
FIGURE 18-3:
Write to TXREG BRG Output (Shift Clock) RC6/TX1/CK1 (pin) TXIF bit (Interrupt Reg. Flag)
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Word 1 Word 2
START bit
bit 0
bit 1 Word 1
bit 7/8
STOP bit
START bit Word 2
bit 0
TRMT bit (Transmit Shift Reg. Empty Flag) Note:
Word 1 Transmit Shift Reg.
Word 2 Transmit Shift Reg.
This timing diagram shows two consecutive transmissions.
TABLE 18-6:
Name INTCON PIR1 PIE1 IPR1 PIR3 PIE3 IPR3 RCSTAx TXSTAx
(1)
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Bit 7 Bit 6 PEIE/GIEL ADIF ADIE ADIP -- -- -- RX9 TX9 Bit 5 TMR0IE RC1IF RC1IE RC1IP RC2IF RC2IE RC2IP SREN TXEN Bit 4 INT0IE TX1IF TX1IE TX1IP TX2IF TX2IE TX2IP CREN SYNC Bit 3 RBIE SSPIF SSPIE SSPIP TMR4IF TMR4IE TMR4IP ADDEN -- Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP CCP5IF CCP5IE CCP5IP FERR BRGH Bit 1 INT0IF TMR2IF TMR2IE TMR2IP CCP4IF CCP4IE CCP4IP OERR TRMT Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP3IF CCP3IE CCP3IP RX9D TX9D Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000 Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
GIE/GIEH PSPIF PSPIE PSPIP -- -- -- SPEN CSRC
TXREGx(1) USART Transmit Register
(1)
SPBRGx(1) Baud Rate Generator Register
Legend: x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for Asynchronous Transmission. Note 1: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
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18.2.2 USART ASYNCHRONOUS RECEIVER 18.2.3 SETTING UP 9-BIT MODE WITH ADDRESS DETECT
The USART receiver block diagram is shown in Figure 18-4. The data is received on the pin (RC7/RX1/DT1 or RG2/RX2/DT2) and drives the data recovery block. The data recovery block is actually a high speed shifter operating at 16 times the baud rate, whereas the main receive serial shifter operates at the bit rate or at FOSC. This mode would typically be used in RS-232 systems. To set up an Asynchronous Reception: 1. Initialize the SPBRG register for the appropriate baud rate. If a high speed baud rate is desired, set bit BRGH (Section 18.1). 2. Enable the asynchronous serial port by clearing bit SYNC and setting bit SPEN. 3. If interrupts are desired, set enable bit RCxIE. 4. If 9-bit reception is desired, set bit RX9. 5. Enable the reception by setting bit CREN. 6. Flag bit RCxIF will be set when reception is complete and an interrupt will be generated if enable bit RCxIE was set. 7. Read the RCSTAx register to get the ninth bit (if enabled) and determine if any error occurred during reception. 8. Read the 8-bit received data by reading the RCREG register. 9. If any error occurred, clear the error by clearing enable bit CREN. 10. If using interrupts, ensure that the GIE and PEIE bits in the INTCON register (INTCON<7:6>) are set. This mode would typically be used in RS-485 systems. To set up an Asynchronous Reception with Address Detect Enable: 1. Initialize the SPBRGx register for the appropriate baud rate. If a high speed baud rate is required, set the BRGH bit. 2. Enable the asynchronous serial port by clearing the SYNC bit and setting the SPEN bit. 3. If interrupts are required, set the RCEN bit and select the desired priority level with the RCIP bit. 4. Set the RX9 bit to enable 9-bit reception. 5. Set the ADDEN bit to enable address detect. 6. Enable reception by setting the CREN bit. 7. The RCxIF bit will be set when reception is complete. The interrupt will be Acknowledged if the RCxIE and GIE bits are set. 8. Read the RCSTAx register to determine if any error occurred during reception, as well as read bit 9 of data (if applicable). 9. Read RCREGx to determine if the device is being addressed. 10. If any error occurred, clear the CREN bit. 11. If the device has been addressed, clear the ADDEN bit to allow all received data into the receive buffer and interrupt the CPU.
FIGURE 18-4:
USART RECEIVE BLOCK DIAGRAM
CREN x64 Baud Rate CLK / 64 or / 16 MSb STOP (8) 7 RSR Register *** 1 LSb 0 START OERR FERR
SPBRG
Baud Rate Generator RX9 RX pin Pin Buffer and Control Data Recovery RX9D RCREG Register FIFO
SPEN 8 Interrupt RCIF RCIE Data Bus
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FIGURE 18-5:
RX (pin) Rcv Shift Reg Rcv Buffer Reg Read Rcv Buffer Reg RCREG RCIF (Interrupt Flag) OERR bit CREN Note: This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word, causing the OERR (overrun) bit to be set.
ASYNCHRONOUS RECEPTION
START bit bit0 bit1 bit7/8 STOP bit START bit bit0 bit7/8 STOP bit START bit bit7/8 STOP bit
Word 1 RCREG
Word 2 RCREG
TABLE 18-7:
Name INTCON PIR1 PIE1 IPR1 PIR3 PIE3 IPR3 RCSTAx
(1)
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Bit 7 Bit 6 PEIE/ GIEL ADIF ADIE ADIP -- -- -- RX9 TX9 Bit 5 TMR0IE RCIF RCIE RCIP RC2IF RC2IE RC2IP SREN TXEN Bit 4 INT0IE TXIF TXIE TXIP TX2IF TX2IE TX2IP CREN SYNC Bit 3 RBIE SSPIF SSPIE SSPIP TMR4IF Bit 2 TMR0IF CCP1IF Bit 1 INT0IF TMR2IF Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP3IF CCP3IE CCP3IP RX9D TX9D Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 -- BRGH TRMT 0000 -010 0000 0000 Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
GIE/ GIEH PSPIF PSPIE PSPIP -- -- -- SPEN CSRC
CCP1IE TMR2IE CCP1IP TMR2IP CCP5IF CCP4IF CCP4IE CCP4IP OERR
TMR4IE CCP5IE TMR4IP CCP5IP ADDEN FERR
TXREGx(1) USART Receive Register TXSTAx(1) SPBRGx(1) Baud Rate Generator Register
Legend: x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for Asynchronous Reception. Note 1: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
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18.3 USART Synchronous Master Mode
USART1, PIE3<4> for USART2). Flag bit TXxIF will be set, regardless of the state of enable bit TXxIE, and cannot be cleared in software. It will reset only when new data is loaded into the TXREGx register. While flag bit TXxIF indicates the status of the TXREGx register, another bit TRMT (TXSTAx<1>) shows the status of the TSR register. TRMT is a read only bit, which is set when the TSR is empty. No interrupt logic is tied to this bit, so the user has to poll this bit in order to determine if the TSR register is empty. The TSR is not mapped in data memory, so it is not available to the user. To set up a Synchronous Master Transmission: 1. 2. 3. 4. 5. 6. 7. Initialize the SPBRG register for the appropriate baud rate (Section 18.1). Enable the synchronous master serial port by setting bits SYNC, SPEN, and CSRC. If interrupts are desired, set enable bit TXxIE in the appropriate PIE register. If 9-bit transmission is desired, set bit TX9. Enable the transmission by setting bit TXEN. If 9-bit transmission is selected, the ninth bit should be loaded in bit TX9D. Start transmission by loading data to the TXREGx register. Note: TXIF is not cleared immediately upon loading data into the transmit buffer TXREG. The flag bit becomes valid in the second instruction cycle following the load instruction.
In Synchronous Master mode, the data is transmitted in a half-duplex manner (i.e., transmission and reception do not occur at the same time). When transmitting data, the reception is inhibited and vice versa. Synchronous mode is entered by setting bit SYNC (TXSTAx<4>). In addition, enable bit SPEN (RCSTAx<7>) is set in order to configure the appropriate I/O pins to CK (clock) and DT (data) lines, respectively. The Master mode indicates that the processor transmits the master clock on the CK line. The Master mode is entered by setting bit CSRC (TXSTAx<7>).
18.3.1
USART SYNCHRONOUS MASTER TRANSMISSION
The USART transmitter block diagram is shown in Figure 18-1. The heart of the transmitter is the Transmit (serial) Shift Register (TSR). The shift register obtains its data from the read/write transmit buffer register, TXREG. The TXREGx register is loaded with data in software. The TSR register is not loaded until the last bit has been transmitted from the previous load. As soon as the last bit is transmitted, the TSR is loaded with new data from the TXREGx (if available). Once the TXREGx register transfers the data to the TSR register (occurs in one TCYCLE), the TXREGx is empty and interrupt bit TXxIF (PIR1<4> for USART1, PIR3<4> for USART2) is set. The interrupt can be enabled/disabled by setting/clearing enable bit TXxIE (PIE1<4> for
TABLE 18-8:
Name INTCON PIR1 PIE1 IPR1 PIR3 PIE3 IPR3 RCSTAx
(1) (1)
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Bit 6 PEIE/ GIEL ADIF ADIE ADIP -- -- -- RX9 Bit 5 TMR0IE RCIF RCIE RCIP RC2IF RC2IE RC2IP SREN Bit 4 INT0IE TXIF TXIE TXIP TX2IF TX2IE TX2IP CREN Bit 3 RBIE SSPIF SSPIE SSPIP TMR4IF TMR4IE TMR4IP ADDEN Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP CCP5IF CCP5IE CCP5IP FERR Bit 1 INT0IF TMR2IF TMR2IE TMR2IP CCP4IF CCP4IE CCP4IP OERR Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP3IF CCP3IE CCP3IP RX9D Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 SYNC -- BRGH TRMT TX9D 0000 -010 0000 0000 Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
Bit 7 GIE/ GIEH PSPIF PSPIE PSPIP -- -- -- SPEN
TXREGx
USART Transmit Register CSRC TX9 TXEN
TXSTAx(1) SPBRGx
(1)
Baud Rate Generator Register
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for Synchronous Master Transmission. Note 1: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
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FIGURE 18-6: SYNCHRONOUS TRANSMISSION
Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX1/DT1 pin RC6/TX1/CK1 pin Write to TXREG Reg TXIF bit (Interrupt Flag)
TRMT TRMT bit
bit 0
bit 1 Word 1
bit 2
bit 7
bit 0
bit 1 Word 2
bit 7
Write Word1
Write Word2
TXEN bit Note:
'1'
'1'
Sync Master mode; SPBRG = 0. Continuous transmission of two 8-bit words.
FIGURE 18-7:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
bit0 bit1 bit2 bit6 bit7
RC7/RX1/DT1 pin RC6/TX1/CK1 pin Write to TXREG reg
TXIF bit
TRMT bit
TXEN bit
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18.3.2 USART SYNCHRONOUS MASTER RECEPTION
Once Synchronous mode is selected, reception is enabled by setting either enable bit SREN (RCSTAx<5>), or enable bit CREN (RCSTAx<4>). Data is sampled on the RXx pin (RC7/RX1/DT1 or RG2/RX2/DT2) on the falling edge of the clock. If enable bit SREN is set, only a single word is received. If enable bit CREN is set, the reception is continuous until CREN is cleared. If both bits are set, then CREN takes precedence. To set up a Synchronous Master Reception: 1. 2. 3. Initialize the SPBRGx register for the appropriate baud rate (Section 18.1). Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC. Ensure bits CREN and SREN are clear. If interrupts are desired, set enable bit RCxIE in the appropriate PIE register. 5. If 9-bit reception is desired, set bit RX9. 6. If a single reception is required, set bit SREN. For continuous reception, set bit CREN. 7. Interrupt flag bit RCxIF will be set when reception is complete and an interrupt will be generated if the enable bit RCxIE was set. 8. Read the RCSTAx register to get the ninth bit (if enabled) and determine if any error occurred during reception. 9. Read the 8-bit received data by reading the RCREGx register. 10. If any error occurred, clear the error by clearing bit CREN. 11. If using interrupts, ensure that the GIE and PEIE bits in the INTCON register (INTCON<7:6>) are set. 4.
TABLE 18-9:
Name INTCON PIR1 PIE1 IPR1 PIR3 PIE3 IPR3 RCSTAx(1) TXREGx(1) TXSTAx(1)
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
Bit 6 Bit 5 TMR0IE RC1IF RC1IE RC1IP RC2IF RC2IE RC2IP SREN TXEN Bit 4 INT0IE TX1IF TX1IE TX1IP TX2IF TX2IE TX2IP CREN SYNC Bit 3 RBIE SSPIF SSPIE SSPIP TMR4IF TMR4IE TMR4IP ADDEN -- Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP CCP5IF CCP5IE CCP5IP FERR BRGH Bit 1 INT0IF TMR2IF TMR2IE TMR2IP CCP4IF CCP4IE CCP4IP OERR TRMT Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP3IF CCP3IE CCP3IP RX9D TX9D Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000 Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
Bit 7
GIE/GIEH PEIE/GIEL PSPIF PSPIE PSPIP -- -- -- SPEN CSRC ADIF ADIE ADIP -- -- -- RX9 TX9
USART Receive Register
SPBRGx(1) Baud Rate Generator Register
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for Synchronous Master Reception. Note 1: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
FIGURE 18-8:
RC7/RX1/DT1 pin RC6/TX1/CK1 pin Write to bit SREN SREN bit CREN bit '0'
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
'0'
(Interrupt)
RCIF bit Read RXREG
Note:
Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.
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18.4 USART Synchronous Slave Mode
To set up a Synchronous Slave Transmission: 1. Enable the synchronous slave serial port by setting bits SYNC and SPEN and clearing bit CSRC. Clear bits CREN and SREN. If interrupts are desired, set enable bit TXxIE. If 9-bit transmission is desired, set bit TX9. Enable the transmission by setting enable bit TXEN. If 9-bit transmission is selected, the ninth bit should be loaded in bit TX9D. Start transmission by loading data to the TXREGx register. If using interrupts, ensure that the GIE and PEIE bits in the INTCON register (INTCON<7:6>) are set. Synchronous Slave mode differs from the Master mode in the fact that the shift clock is supplied externally at the TXx pin (RC6/TX1/CK1 or RG1/TX2/CK2), instead of being supplied internally in Master mode. TRISC<6> must be set for this mode. This allows the device to transfer or receive data while in SLEEP mode. Slave mode is entered by clearing bit CSRC (TXSTAx<7>).
2. 3. 4. 5. 6. 7. 8.
18.4.1
USART SYNCHRONOUS SLAVE TRANSMIT
The operation of the Synchronous Master and Slave modes are identical, except in the case of the SLEEP mode. If two words are written to the TXREG and then the SLEEP instruction is executed, the following will occur: a) b) c) d) The first word will immediately transfer to the TSR register and transmit. The second word will remain in TXREG register. Flag bit TXxIF will not be set. When the first word has been shifted out of TSR, the TXREGx register will transfer the second word to the TSR and flag bit TXxIF will now be set. If enable bit TXxIE is set, the interrupt will wake the chip from SLEEP. If the global interrupt is enabled, the program will branch to the interrupt vector.
e)
TABLE 18-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Name INTCON PIR1 PIE1 IPR1 PIR3 PIE3 IPR3 RCSTAx
(1)
Bit 7 GIE/ GIEH PSPIF PSPIE PSPIP -- -- -- SPEN CSRC
Bit 6 PEIE/ GIEL ADIF ADIE ADIP -- -- -- RX9 TX9
Bit 5 TMR0IE RC1IF RC1IE RC1IP RC2IF RC2IE RC2IP SREN TXEN
Bit 4 INT0IE TX1IF TX1IE TX1IP TX2IF TX2IE TX2IP CREN SYNC
Bit 3 RBIE SSPIF SSPIE SSPIP TMR4IF TMR4IE TMR4IP ADDEN --
Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP CCP5IF CCP5IE CCP5IP FERR BRGH
Bit 1 INT0IF TMR2IF TMR2IE TMR2IP CCP4IF CCP4IE CCP4IP OERR TRMT
Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP3IF CCP3IE CCP3IP RX9D TX9D
Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
TXREGx(1) USART Transmit Register TXSTAx(1) SPBRGx(1) Baud Rate Generator Register
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for Synchronous Slave Transmission. Note 1: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
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18.4.2 USART SYNCHRONOUS SLAVE RECEPTION
To set up a Synchronous Slave Reception: 1. Enable the synchronous master serial port by setting bits SYNC and SPEN and clearing bit CSRC. If interrupts are desired, set enable bit RCxIE. If 9-bit reception is desired, set bit RX9. To enable reception, set enable bit CREN. Flag bit RCxIF will be set when reception is complete. An interrupt will be generated if enable bit RCxIE was set. Read the RCSTAx register to get the ninth bit (if enabled) and determine if any error occurred during reception. Read the 8-bit received data by reading the RCREGx register. If any error occurred, clear the error by clearing bit CREN. If using interrupts, ensure that the GIE and PEIE bits in the INTCON register (INTCON<7:6>) are set. The operation of the Synchronous Master and Slave modes is identical, except in the case of the SLEEP mode and bit SREN, which is a "don't care" in Slave mode. If receive is enabled by setting bit CREN prior to the SLEEP instruction, then a word may be received during SLEEP. On completely receiving the word, the RSR register will transfer the data to the RCREG register, and if enable bit RCIE bit is set, the interrupt generated will wake the chip from SLEEP. If the global interrupt is enabled, the program will branch to the interrupt vector.
2. 3. 4. 5.
6.
7. 8. 9.
TABLE 18-11: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name INTCON PIR1 PIE1 IPR1 PIR3 PIE3 IPR3 RCSTAx
(1)
Bit 7 GIE/ GIEH PSPIF PSPIE PSPIP -- -- -- SPEN CSRC
Bit 6 PEIE/ GIEL ADIF ADIE ADIP -- -- -- RX9 TX9
Bit 5 TMR0IE RC1IF RC1IE RC1IP RC2IF RC2IE RC2IP SREN TXEN
Bit 4 INT0IE TX1IF TX1IE TX1IP TX2IF TX2IE TX2IP CREN SYNC
Bit 3 RBIE SSPIF SSPIE SSPIP TMR4IF TMR4IE TMR4IP ADDEN --
Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP CCP5IF CCP5IE CCP5IP FERR BRGH
Bit 1 INT0IF TMR2IF TMR2IE TMR2IP CCP4IF CCP4IE CCP4IP OERR TRMT
Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP3IF CCP3IE CCP3IP RX9D TX9D
Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 --00 0000 --00 0000 --11 1111 0000 000x 0000 0000 0000 -010 0000 0000
TXREGx(1) TXSTAx(1) SPBRGx(1)
USART Receive Register Baud Rate Generator Register
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for Synchronous Slave Reception. Note 1: Register names generically refer to both of the identically named registers for the two USART modules, where `x' indicates the particular module. Bit names and RESET values are identical between modules.
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19.0 10-BIT ANALOG-TO-DIGITAL CONVERTER (A/D) MODULE
The module has five registers: * * * * * A/D Result High Register (ADRESH) A/D Result Low Register (ADRESL) A/D Control Register 0 (ADCON0) A/D Control Register 1 ((ADCON1) A/D Control Register 2 ((ADCON2)
The analog-to-digital (A/D) converter module has 12 inputs for the PIC18F6X20 devices and 16 for the PIC18F8X20 devices. This module allows conversion of an analog input signal to a corresponding 10-bit digital number.
The ADCON0 register, shown in Register 19-1, controls the operation of the A/D module. The ADCON1 register, shown in Register 19-2, configures the functions of the port pins. The ADCON2 register, shown in Register 19-3, configures the A/D clock source and justification.
REGISTER 19-1:
ADCON0 REGISTER
U-0 -- bit 7 U-0 -- R/W-0 CHS3 R/W-0 CHS2 R/W-0 CHS1 R/W-0 CHS0 R/W-0 GO/DONE R/W-0 ADON bit 0
bit 7-6 bit 5-2
Unimplemented: Read as '0' CHS3:CHS0: Analog Channel Select bits 0000 = Channel 0 (AN0) 0001 = Channel 1 (AN1) 0010 = Channel 2 (AN2) 0011 = Channel 3 (AN3) 0100 = Channel 4 (AN4) 0101 = Channel 5 (AN5) 0110 = Channel 6 (AN6) 0111 = Channel 7 (AN7) 1000 = Channel 8 (AN8) 1001 = Channel 9 (AN9) 1010 = Channel 10 (AN10) 1011 = Channel 11 (AN11) 1100 = Channel 12 (AN12)(1) 1101 = Channel 13 (AN13)(1) 1110 = Channel 14 (AN14)(1) 1111 = Channel 15 (AN15)(1) Note 1: These channels are not available on the PIC18F6X20 (64-pin) devices.
bit 1
GO/DONE: A/D Conversion Status bit When ADON = 1: 1 = A/D conversion in progress (setting this bit starts the A/D conversion, which is automatically cleared by hardware when the A/D conversion is complete) 0 = A/D conversion not in progress ADON: A/D On bit 1 = A/D converter module is enabled 0 = A/D converter module is disabled Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 0
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REGISTER 19-2: ADCON1 REGISTER
U-0 -- bit 7 bit 7-6 bit 5-4 Unimplemented: Read as '0' VCFG1:VCFG0: Voltage Reference Configuration bits: VCFG1 VCFG0 00 01 10 11 bit 3-0 A/D VREF+ AVDD External VREF+ AVDD External VREF+ A/D VREFAVSS AVSS External VREFExternal VREFU-0 -- R/W-0 VCFG1 R/W-0 VCFG0 R/W-0 PCFG3 R/W-0 PCFG2 R/W-0 PCFG1 R/W-0 PCFG0 bit 0
PCFG3:PCFG0: A/D Port Configuration Control bits: AN15 AN14 AN13 AN12 PCFG3 PCFG0 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Note: Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown AN10 AN11 AN9 AN8 AN7 AN6 AN5 AN4 AN3 AN2 AN1 A A A A A A A A A A A A A A D D AN0 A A A A A A A A A A A A A A A D
A D D D D D D D D D D D D D D D
A D D D D D D D D D D D D D D D
A A D D D D D D D D D D D D D D
A A A D D D D D D D D D D D D D
A A A A D D D D D D D D D D D D
A A A A A D D D D D D D D D D D
A A A A A A D D D D D D D D D D
A A A A A A A D D D D D D D D D
A A A A A A A A D D D D D D D D
A A A A A A A A A D D D D D D D
A A A A A A A A A A D D D D D D
A A A A A A A A A A A D D D D D
A A A A A A A A A A A A D D D D
A A A A A A A A A A A A A D D D
A = Analog input
D = Digital I/O
Shaded cells indicate A/D channels available only on PIC18F8X20 devices.
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REGISTER 19-3: ADCON2 REGISTER
R/W-0 ADFM bit 7 bit 7 ADFM: A/D Result Format Select bit 1 = Right justified 0 = Left justified Unimplemented: Read as '0' ADCS1:ADCS0: A/D Conversion Clock Select bits 000 = FOSC/2 001 = FOSC/8 010 = FOSC/32 011 = FRC (clock derived from an RC oscillator = 1 MHz max) 100 = FOSC/4 101 = FOSC/16 110 = FOSC/64 111 = FRC (clock derived from an RC oscillator = 1 MHz max) Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown U-0 -- U-0 -- U-0 -- U-0 -- R/W-0 ADCS2 R/W-0 ADCS1 R/W-0 ADCS0 bit 0
bit 6-3 bit 2-0
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The analog reference voltage is software selectable to either the device's positive and negative supply voltage (VDD and VSS), or the voltage level on the RA3/AN3/VREF+ pin and RA2/AN2/VREF- pin. The A/D converter has a unique feature of being able to operate while the device is in SLEEP mode. To operate in SLEEP, the A/D conversion clock must be derived from the A/D's internal RC oscillator. The output of the sample and hold is the input into the converter, which generates the result via successive approximation. A device RESET forces all registers to their RESET state. This forces the A/D module to be turned off and any conversion is aborted. Each port pin associated with the A/D converter can be configured as an analog input (RA3 can also be a voltage reference), or as a digital I/O. The ADRESH and ADRESL registers contain the result of the A/D conversion. When the A/D conversion is complete, the result is loaded into the ADRESH/ADRESL registers, the GO/DONE bit (ADCON0 register) is cleared, and A/D interrupt flag bit, ADIF, is set. The block diagram of the A/D module is shown in Figure 19-1.
FIGURE 19-1:
A/D BLOCK DIAGRAM
CHS3:CHS0 1111 1110 1101 1100 1011 1010 1001 1000 0111 0110 0101 0100 VAIN AN15(1) AN14(1) AN13(1) AN12(1) AN11 AN10 AN9 AN8 AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
10-bit Converter A/D
(Input Voltage)
0011 0010
VCFG1:VCFG0 VDD Reference Voltage VREF+ VREFVSS
0001 0000
Note 1: Channels AN15 through AN12 are not available on PIC18F6X20 devices. 2: I/O pins have diode protection to VDD and VSS.
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The value in the ADRESH/ADRESL registers is not modified for a Power-on Reset. The ADRESH/ADRESL registers will contain unknown data after a Power-on Reset. After the A/D module has been configured as desired, the selected channel must be acquired before the conversion is started. The analog input channels must have their corresponding TRIS bits selected as an input. To determine acquisition time, see Section 19.1. After this acquisition time has elapsed, the A/D conversion can be started. The following steps should be followed to do an A/D conversion: 1. Configure the A/D module: * Configure analog pins, voltage reference and digital I/O (ADCON1) * Select A/D input channel (ADCON0) * Select A/D conversion clock (ADCON2) * Turn on A/D module (ADCON0) Configure A/D interrupt (if desired): * Clear ADIF bit * Set ADIE bit * Set GIE bit Wait the required acquisition time. Start conversion: * Set GO/DONE bit (ADCON0 register) Wait for A/D conversion to complete, by either: * Polling for the GO/DONE bit to be cleared OR * Waiting for the A/D interrupt Read A/D Result registers (ADRESH:ADRESL); clear bit ADIF, if required. For next conversion, go to step 1 or step 2, as required. The A/D conversion time per bit is defined as TAD. A minimum wait of 2 TAD is required before next acquisition starts.
2.
3. 4. 5.
6. 7.
FIGURE 19-2:
ANALOG INPUT MODEL
VDD VT = 0.6V RIC 1k Sampling Switch SS RSS
Rs
ANx
VAIN
CPIN 5 pF VT = 0.6V
I leakage 500 nA
CHOLD = 120 pF
VSS
Legend: CPIN = input capacitance VT = threshold voltage I LEAKAGE = leakage current at the pin due to various junctions = interconnect resistance RIC = sampling switch SS = sample/hold capacitance (from DAC) CHOLD RSS = sampling switch resistance
6V 5V VDD 4V 3V 2V
5 6 7 8 9 10 11 Sampling Switch ( k )
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19.1 A/D Acquisition Requirements
For the A/D converter to meet its specified accuracy, the charge holding capacitor (CHOLD) must be allowed to fully charge to the input channel voltage level. The analog input model is shown in Figure 19-2. The source impedance (RS) and the internal sampling switch (RSS) impedance directly affect the time required to charge the capacitor CHOLD. The sampling switch (RSS) impedance varies over the device voltage (VDD). The source impedance affects the offset voltage at the analog input (due to pin leakage current). The maximum recommended impedance for analog sources is 2.5 k. After the analog input channel is selected (changed), this acquisition must be done before the conversion can be started. Note: When the conversion is started, the holding capacitor is disconnected from the input pin. To calculate the minimum acquisition time, Equation 19-1 may be used. This equation assumes that 1/2 LSb error is used (1024 steps for the A/D). The 1/2 LSb error is the maximum error allowed for the A/D to meet its specified resolution. Example 19-1 shows the calculation of the minimum required acquisition time, TACQ. This calculation is based on the following application system assumptions: CHOLD Rs Conversion Error VDD Temperature VHOLD = = = = = 120 pF 2.5 k 1/2 LSb 5V Rss = 7 k 50C (system max.) 0V @ time = 0
EQUATION 19-1:
TACQ = =
ACQUISITION TIME
Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient TAMP + TC + TCOFF
EQUATION 19-2:
VHOLD or TC = =
A/D MINIMUM CHARGING TIME
(VREF - (VREF/2048)) * (1 - e(-Tc/CHOLD(RIC + RSS + RS))) -(120 pF)(1 k + RSS + RS) ln(1/2047)
EXAMPLE 19-1:
TACQ TACQ TC = = =
CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
TAMP + TC + TCOFF 2 s + TC + [(Temp - 25C)(0.05 s/C)] -CHOLD (RIC + RSS + RS) ln(1/2047) -120 pF (1 k + 7 k + 2.5 k) ln(0.0004885) -120 pF (10.5 k) ln(0.0004885) -1.26 s (-7.6241) 9.61 s 2 s + 9.61 s + [(50C - 25C)(0.05 s/C)] 11.61 s + 1.25 s 12.86 s
Temperature coefficient is only required for temperatures > 25C.
TACQ
=
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19.2 Selecting the A/D Conversion Clock 19.3 Configuring Analog Port Pins
The ADCON1, TRISA, TRISF and TRISH registers control the operation of the A/D port pins. The port pins needed as analog inputs must have their corresponding TRIS bits set (input). If the TRIS bit is cleared (output), the digital output level (VOH or VOL) will be converted. The A/D operation is independent of the state of the CHS3:CHS0 bits and the TRIS bits. Note 1: When reading the port register, all pins configured as analog input channels will read as cleared (a low level). Pins configured as digital inputs will convert an analog input. Analog levels on a digitally configured input will not affect the conversion accuracy. 2: Analog levels on any pin defined as a digital input may cause the input buffer to consume current out of the device's specification limits.
The A/D conversion time per bit is defined as TAD. The A/D conversion requires 12 TAD per 10-bit conversion. The source of the A/D conversion clock is software selectable. There are seven possible options for TAD: * * * * * * * 2 TOSC 4 TOSC 8 TOSC 16 TOSC 32 TOSC 64 TOSC Internal RC oscillator
For correct A/D conversions, the A/D conversion clock (TAD) must be selected to ensure a minimum TAD time of 1.6 s. Table 19-1 shows the resultant TAD times derived from the device operating frequencies and the A/D clock source selected.
TABLE 19-1:
TAD vs. DEVICE OPERATING FREQUENCIES
AD Clock Source (TAD) Maximum Device Frequency PIC18FXX20 1.25 MHz 2.50 MHz 5.00 MHz 10.0 MHz 20.0 MHz 40.0 MHz -- PIC18LFXX20 666 kHz 1.33 MHz 2.67 MHz 5.33 MHz 10.67 MHz 21.33 MHz --
Operation 2 TOSC 4 TOSC 8 TOSC 16 TOSC 32 TOSC 64 TOSC RC
ADCS2:ADCS0 000 100 001 101 010 110 x11
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19.4 A/D Conversions 19.5 Use of the CCP2 Trigger
Figure 19-3 shows the operation of the A/D converter after the GO bit has been set. Clearing the GO/DONE bit during a conversion will abort the current conversion. The A/D result register pair will NOT be updated with the partially completed A/D conversion sample. That is, the ADRESH:ADRESL registers will continue to contain the value of the last completed conversion (or the last value written to the ADRESH:ADRESL registers). After the A/D conversion is aborted, a 2 TAD wait is required before the next acquisition is started. After this 2 TAD wait, acquisition on the selected channel is automatically started. Note: The GO/DONE bit should NOT be set in the same instruction that turns on the A/D. An A/D conversion can be started by the "special event trigger" of the CCP2 module. This requires that the CCP2M3:CCP2M0 bits (CCP2CON<3:0>) be programmed as 1011 and that the A/D module is enabled (ADON bit is set). When the trigger occurs, the GO/DONE bit will be set, starting the A/D conversion, and the Timer1 (or Timer3) counter will be reset to zero. Timer1 (or Timer3) is reset to automatically repeat the A/D acquisition period with minimal software overhead (moving ADRESH/ADRESL to the desired location). The appropriate analog input channel must be selected and the minimum acquisition done before the "special event trigger" sets the GO/DONE bit (starts a conversion). If the A/D module is not enabled (ADON is cleared), the "special event trigger" will be ignored by the A/D module, but will still reset the Timer1 (or Timer3) counter.
FIGURE 19-3:
A/D CONVERSION TAD CYCLES
TCY - TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11 b0 b1 b3 b0 b4 b2 b5 b7 b6 b8 b9 Conversion Starts Holding capacitor is disconnected from analog input (typically 100 ns) Set GO bit Next Q4: ADRESH/ADRESL is loaded, GO bit is cleared, ADIF bit is set, holding capacitor is connected to analog input.
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TABLE 19-2:
Name INTCON PIR1 PIE1 IPR1 PIR2 PIE2 IPR2 ADRESH ADRESL ADCON0 ADCON1 ADCON2 PORTA TRISA PORTF LATF TRISF PORTH(1) LATH(1) TRISH(1)
SUMMARY OF A/D REGISTERS
Bit 6 PEIE/ GIEL ADIF ADIE ADIP CMIF CMIE CMIP Bit 5 TMR0IE RCIF RCIE RCIP -- -- -- Bit 4 INT0IE TXIF TXIE TXIP -- -- -- Bit 3 RBIE SSPIF SSPIE SSPIP BCLIF BCLIE BCLIP Bit 2 TMR0IF CCP1IF CCP1IE CCP1IP LVDIF LVDIE LVDIP Bit 1 INT0IF TMR2IF TMR2IE TMR2IP TMR3IF TMR3IE TMR3IP Bit 0 RBIF TMR1IF TMR1IE TMR1IP CCP2IF CCP2IE CCP2IP Value on POR, BOR 0000 0000 0000 0000 0000 0000 0111 1111 -0-- 0000 -0-- 0000 -0-- 0000 xxxx xxxx xxxx xxxx CHS3 VCFG0 -- RA4 RF4 LATF4 RH4 LATH4 CHS1 PCFG3 -- RA3 RF3 LATF3 RH3 LATH3 CHS0 PCFG2 ADCS2 RA2 RF2 LATF2 RH2 LATH2 GO/DONE PCFG1 ADCS1 RA1 RF1 LATF1 RH1 LATH1 ADON PCFG0 ADCS0 RA0 RF0 LATF0 RH0 LATH0 --00 0000 --00 0000 0--- -000 --0x 0000 --11 1111 x000 0000 xxxx xxxx 1111 1111 0000 xxxx xxxx xxxx 1111 1111 Value on all other RESETS 0000 0000 0000 0000 0000 0000 0111 1111 -0-- 0000 -0-- 0000 -0-- 0000 uuuu uuuu uuuu uuuu --00 0000 --00 0000 0--- -000 --0u 0000 --11 1111 u000 0000 uuuu uuuu 1111 1111 0000 xxxx uuuu uuuu 1111 1111
Bit 7 GIE/ GIEH PSPIF PSPIE PSPIP -- -- --
A/D Result Register High Byte A/D Result Register Low Byte -- -- ADFM -- -- RF7 LATF7 RH7 LATH7 -- -- -- RA6 RF6 LATF6 RH6 LATH6 CHS3 VCFG1 -- RA5 RF5 LATF5 RH5 LATH5
PORTA Data Direction Register
PORTF Data Direction Control Register
PORTH Data Direction Control Register
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used for A/D conversion. Note 1: Only available on PIC18F8X20 devices.
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NOTES:
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PIC18FXX20
20.0 COMPARATOR MODULE
The comparator module contains two analog comparators. The inputs to the comparators are multiplexed with the RF1 through RF6 pins. The on-chip Voltage Reference (Section 21.0) can also be an input to the comparators. The CMCON register, shown as Register 20-1, controls the comparator input and output multiplexers. A block diagram of the various comparator configurations is shown in Figure 20-1.
REGISTER 20-1:
CMCON REGISTER
R-0 C2OUT bit 7 R-0 C1OUT R/W-0 C2INV R/W-0 C1INV R/W-0 CIS R/W-0 CM2 R/W-0 CM1 R/W-0 CM0 bit 0
bit 7
C2OUT: Comparator 2 Output bit When C2INV = 0: 1 = C2 VIN+ > C2 VIN0 = C2 VIN+ < C2 VINWhen C2INV = 1: 1 = C2 VIN+ < C2 VIN0 = C2 VIN+ > C2 VINC1OUT: Comparator 1 Output bit When C1INV = 0: 1 = C1 VIN+ > C1 VIN0 = C1 VIN+ < C1 VINWhen C1INV = 1: 1 = C1 VIN+ < C1 VIN0 = C1 VIN+ > C1 VINC2INV: Comparator 2 Output Inversion bit 1 = C2 output inverted 0 = C2 output not inverted C1INV: Comparator 1 Output Inversion bit 1 = C1 Output inverted 0 = C1 Output not inverted CIS: Comparator Input Switch bit When CM2:CM0 = 110: 1 = C1 VIN- connects to RF5/AN10 C2 VIN- connects to RF3/AN8 0 = C1 VIN- connects to RF6/AN11 C2 VIN- connects to RF4/AN9 CM2:CM0: Comparator Mode bits Figure 20-1 shows the Comparator modes and CM2:CM0 bit settings Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6
bit 5
bit 4
bit 3
bit 2
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20.1 Comparator Configuration
There are eight modes of operation for the comparators. The CMCON register is used to select these modes. Figure 20-1 shows the eight possible modes. The TRISF register controls the data direction of the comparator pins for each mode. If the Comparator mode is changed, the comparator output level may not be valid for the specified mode change delay shown in Electrical Specifications (Section 26.0). Note: Comparator interrupts should be disabled during a Comparator mode change. Otherwise, a false interrupt may occur.
FIGURE 20-1:
COMPARATOR I/O OPERATING MODES
Comparators Off CM2:CM0 = 111 RF6/AN11
D VINVIN+
Comparators Reset (POR Default Value) CM2:CM0 = 000 RF6/AN11
A VINVIN+
RF5/AN10 A
C1
Off (Read as '0')
RF5/AN10 D
C1
Off (Read as '0')
RF4/AN9 RF3/AN8
A A
VINVIN+
RF4/AN9 C2 Off (Read as '0') RF3/AN8
D D
VINVIN+
C2
Off (Read as '0')
Two Independent Comparators CM2:CM0 = 010 RF6/AN11
A VINVIN+
Two Independent Comparators with Outputs CM2:CM0 = 011 RF6/AN11
A VINVIN+
RF5/AN10 A
C1
C1OUT
RF5/AN10 A RF2/AN7/C1OUT
C1
C1OUT
RF4/AN9 RF3/AN8
A A
VINVIN+
C2
C2OUT
RF4/AN9 RF3/AN8
A A
VINVIN+
C2
C2OUT
RF1/AN6/C2OUT Two Common Reference Comparators CM2:CM0 = 100 RF6/AN11
A VINVIN+
Two Common Reference Comparators with Outputs CM2:CM0 = 101 RF6/AN11
A VINVIN+
RF5/AN10 A
C1
C1OUT
RF5/AN10 A RF2/AN7/C1OUT
C1
C1OUT
RF4/AN9 RF3/AN8
A D
VINVIN+
C2
C2OUT
RF4/AN9 RF3/AN8
A D
VINVIN+
C2
C2OUT
RF1/AN6/C2OUT One Independent Comparator with Output CM2:CM0 = 001 RF6/AN11 RF5/AN10
A A VINVIN+
Four Inputs Multiplexed to Two Comparators CM2:CM0 = 110 RF6/AN11
A CIS = 0 CIS = 1 VINVIN+
C1
C1OUT
RF5/AN10 A RF4/AN9
A A
C1
C1OUT
RF2/AN7/C1OUT
D D VINVIN+
RF3/AN8 C2 Off (Read as '0')
CIS = 0 CIS = 1
VINVIN+
RF4/AN9 RF3/AN8
C2
C2OUT
CVREF
From VREF Module
A = Analog Input, port reads zeros always
D = Digital Input
CIS (CMCON<3>) is the Comparator Input Switch
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20.2 Comparator Operation
20.3.2 INTERNAL REFERENCE SIGNAL
A single comparator is shown in Figure 20-2, along with the relationship between the analog input levels and the digital output. When the analog input at VIN+ is less than the analog input VIN-, the output of the comparator is a digital low level. When the analog input at VIN+ is greater than the analog input VIN-, the output of the comparator is a digital high level. The shaded areas of the output of the comparator in Figure 20-2 represent the uncertainty, due to input offsets and response time. The comparator module also allows the selection of an internally generated voltage reference for the comparators. Section 21.0 contains a detailed description of the Comparator Voltage Reference Module that provides this signal. The internal reference signal is used when comparators are in mode CM<2:0> = 110 (Figure 20-1). In this mode, the internal voltage reference is applied to the VIN+ pin of both comparators.
20.3
Comparator Reference
20.4
Comparator Response Time
An external or internal reference signal may be used, depending on the comparator operating mode. The analog signal present at VIN- is compared to the signal at VIN+, and the digital output of the comparator is adjusted accordingly (Figure 20-2).
Response time is the minimum time, after selecting a new reference voltage or input source, before the comparator output has a valid level. If the internal reference is changed, the maximum delay of the internal voltage reference must be considered when using the comparator outputs. Otherwise, the maximum delay of the comparators should be used (Section 26.0).
FIGURE 20-2:
VIN+ VIN-
SINGLE COMPARATOR
+ -
20.5
Comparator Outputs
Output
VINVIN- VIN+ VIN+
The comparator outputs are read through the CMCON Register. These bits are read only. The comparator outputs may also be directly output to the RF1 and RF2 I/O pins. When enabled, multiplexors in the output path of the RF1 and RF2 pins will switch and the output of each pin will be the unsynchronized output of the comparator. The uncertainty of each of the comparators is related to the input offset voltage and the response time given in the specifications. Figure 20-3 shows the comparator output block diagram. The TRISA bits will still function as an output enable/disable for the RF1 and RF2 pins while in this mode. The polarity of the comparator outputs can be changed using the C2INV and C1INV bits (CMCON<4:5>).
Output Output
20.3.1
EXTERNAL REFERENCE SIGNAL
When external voltage references are used, the comparator module can be configured to have the comparators operate from the same, or different reference sources. However, threshold detector applications may require the same reference. The reference signal must be between VSS and VDD, and can be applied to either pin of the comparator(s).
Note 1: When reading the PORT register, all pins configured as analog inputs will read as a `0'. Pins configured as digital inputs will convert an analog input, according to the Schmitt Trigger input specification. 2: Analog levels on any pin defined as a digital input, may cause the input buffer to consume more current than is specified.
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FIGURE 20-3: COMPARATOR OUTPUT BLOCK DIAGRAM
Port Pins
MULTIPLEX + CxINV
To RF1 or RF2 Pin Bus Data Read CMCON Q EN D
Set CMIF bit
Q From Other Comparator
D EN CL Read CMCON RESET
20.6
Comparator Interrupts
Note:
The comparator interrupt flag is set whenever there is a change in the output value of either comparator. Software will need to maintain information about the status of the output bits, as read from CMCON<7:6>, to determine the actual change that occurred. The CMIF bit (PIR registers) is the comparator interrupt flag. The CMIF bit must be reset by clearing `0'. Since it is also possible to write a '1' to this register, a simulated interrupt may be initiated. The CMIE bit (PIE registers) and the PEIE bit (INTCON register) must be set to enable the interrupt. In addition, the GIE bit must also be set. If any of these bits are clear, the interrupt is not enabled, though the CMIF bit will still be set if an interrupt condition occurs.
If a change in the CMCON register (C1OUT or C2OUT) should occur when a read operation is being executed (start of the Q2 cycle), then the CMIF (PIR registers) interrupt flag may not get set.
The user, in the Interrupt Service Routine, can clear the interrupt in the following manner: a) b) Any read or write of CMCON will end the mismatch condition. Clear flag bit CMIF.
A mismatch condition will continue to set flag bit CMIF. Reading CMCON will end the mismatch condition, and allow flag bit CMIF to be cleared.
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20.7 Comparator Operation During SLEEP 20.9 Analog Input Connection Considerations
When a comparator is active and the device is placed in SLEEP mode, the comparator remains active and the interrupt is functional, if enabled. This interrupt will wake-up the device from SLEEP mode, when enabled. While the comparator is powered up, higher SLEEP currents than shown in the power-down current specification will occur. Each operational comparator will consume additional current, as shown in the comparator specifications. To minimize power consumption while in SLEEP mode, turn off the comparators, CM<2:0> = 111, before entering SLEEP. If the device wakes up from SLEEP, the contents of the CMCON register are not affected.
A simplified circuit for an analog input is shown in Figure 20-4. Since the analog pins are connected to a digital output, they have reverse biased diodes to VDD and VSS. The analog input, therefore, must be between VSS and VDD. If the input voltage deviates from this range by more than 0.6V in either direction, one of the diodes is forward biased and a latchup condition may occur. A maximum source impedance of 10 k is recommended for the analog sources. Any external component connected to an analog input pin, such as a capacitor or a Zener diode, should have very little leakage current.
20.8
Effects of a RESET
A device RESET forces the CMCON register to its RESET state, causing the comparator module to be in the comparator RESET mode, CM<2:0> = 000. This ensures that all potential inputs are analog inputs. Device current is minimized when analog inputs are present at RESET time. The comparators will be powered down during the RESET interval.
FIGURE 20-4:
COMPARATOR ANALOG INPUT MODEL
VDD RS < 10k AIN VT = 0.6V RIC Comparator Input CPIN 5 pF VT = 0.6V ILEAKAGE 500 nA
VA
VSS Legend: CPIN VT ILEAKAGE RIC RS VA = = = = = = Input Capacitance Threshold Voltage Leakage Current at the pin due to various junctions Interconnect Resistance Source Impedance Analog Voltage
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TABLE 20-1:
Name CMCON INTCON PIR2 PIE2 IPR2 PORTF LATF TRISF
REGISTERS ASSOCIATED WITH COMPARATOR MODULE
Bit 6 C1OUT PEIE/ GIEL CMIF CMIE CMIP RF6 LATF6 Bit 5 C2INV CVRR Bit 4 C1INV CVRSS Bit 3 CIS CVR3 RBIE BCLIF BCLIE BCLIP RF3 LATF3 Bit 2 CM2 CVR2 TMR0IF LVDIF LVDIE LVDIP RF2 LATF2 Bit 1 CM1 CVR1 INT0IF Bit 0 CM0 CVR0 RBIF Value on POR Value on all other RESETS
Bit 7 C2OUT GIE/ GIEH -- -- -- RF7 LATF7
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
CVRCON CVREN CVROE
TMR0IE INT0IE -- -- -- RF5 LATF5 -- -- -- RF4 LATF4
TMR3IF CCP2IF -0-- 0000 -0-- 0000 TMR3IE CCP2IE -0-- 0000 -0-- 0000 TMR3IP CCP2IP -1-- 1111 -1-- 1111 RF1 LATF1 RF0 LATF0 x000 0000 u000 0000 xxxx xxxx uuuu uuuu
TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 TRISF1 TRISF0 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented, read as `0'. Shaded cells are unused by the comparator module.
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21.0 COMPARATOR VOLTAGE REFERENCE MODULE
21.1 Configuring the Comparator Voltage Reference
The Comparator Voltage Reference is a 16-tap resistor ladder network that provides a selectable voltage reference. The resistor ladder is segmented to provide two ranges of CVREF values and has a power-down function to conserve power when the reference is not being used. The CVRCON register controls the operation of the reference as shown in Register 21-1. The block diagram is given in Figure 21-1. The comparator reference supply voltage can come from either VDD or VSS, or the external VREF+ and VREF- that are multiplexed with RA3 and RA2. The comparator reference supply voltage is controlled by the CVRSS bit. Note: In order to select external VREF+ and VREFsupply voltages, the Voltage Reference Configuration bits (VCFG1:VCFG0) of the ADCON1 register must be set appropriately.
The Comparator Voltage Reference can output 16 distinct voltage levels for each range. The equations used to calculate the output of the Comparator Voltage Reference are as follows: If CVRR = 1: CVREF= (CVR<3:0>/24) x CVRSRC If CVRR = 0: CVREF = (CVDD x 1/4) + (CVR<3:0>/32) x CVRSRC The settling time of the Comparator Voltage Reference must be considered when changing the CVREF output (Section 26.0).
REGISTER 21-1:
CVRCON REGISTER
R/W-0 CVREN bit 7 R/W-0 CVROE R/W-0 CVRR R/W-0 CVRSS R/W-0 CVR3 R/W-0 CVR2 R/W-0 CVR1 R/W-0 CVR0 bit 0
bit 7
CVREN: Comparator Voltage Reference Enable bit 1 = CVREF circuit powered on 0 = CVREF circuit powered down CVROE: Comparator VREF Output Enable bit(1) 1 = CVREF voltage level is also output on the RF5/AN10/CVREF pin 0 = CVREF voltage is disconnected from the RF5/AN10/CVREF pin CVRR: Comparator VREF Range Selection bit 1 = 0.00 CVRSRC to 0.75 CVRSRC, with CVRSRC/24 step size 0 = 0.25 CVRSRC to 0.75 CVRSRC, with CVRSRC/32 step size CVRSS: Comparator VREF Source Selection bit(2) 1 = Comparator reference source CVRSRC = VREF+ - VREF0 = Comparator reference source CVRSRC = VDD - VSS CVR3:CVR0: Comparator VREF Value Selection bits (0 VR3:VR0 15) When CVRR = 1: CVREF = (CVR<3:0>/ 24) * (CVRSRC) When CVRR = 0: CVREF = 1/4 * (CVRSRC) + (CVR3:CVR0/ 32) * (CVRSRC) Note 1: If enabled for output, RF5 must also be configured as an input by setting TRISF<5> to `1'. 2: In order to select external VREF+ and VREF- supply voltages, the Voltage Reference Configuration bits (VCFG1:VCFG0) of the ADCON1 register must be set appropriately. Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 6
bit 5
bit 4
bit 3-0
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PIC18FXX20
FIGURE 21-1: VOLTAGE REFERENCE BLOCK DIAGRAM
VDD VREF+ CVRSS = 0 CVREN 8R CVRSS = 1 R R 16 Stages R R CVRR 8R CVRSS = 0 CVRSS = 1 VREFCVR3 (From CVRCON<3:0>) CVR0
CVREF
16-1 Analog Mux
Note: R is defined in Section 26.0.
21.2
Voltage Reference Accuracy/Error
21.4
Effects of a RESET
The full range of voltage reference cannot be realized due to the construction of the module. The transistors on the top and bottom of the resistor ladder network (Figure 21-1) keep CVREF from approaching the reference source rails. The voltage reference is derived from the reference source; therefore, the CVREF output changes with fluctuations in that source. The tested absolute accuracy of the voltage reference can be found in Section 26.0.
A device RESET disables the voltage reference by clearing bit CVREN (CVRCON<7>). This RESET also disconnects the reference from the RA2 pin by clearing bit CVROE (CVRCON<6>) and selects the high voltage range by clearing bit CVRR (CVRCON<5>). The VRSS value select bits, CVRCON<3:0>, are also cleared.
21.5
Connection Considerations
21.3
Operation During SLEEP
When the device wakes up from SLEEP through an interrupt or a Watchdog Timer time-out, the contents of the CVRCON register are not affected. To minimize current consumption in SLEEP mode, the voltage reference should be disabled.
The voltage reference module operates independently of the comparator module. The output of the reference generator may be connected to the RF5 pin if the TRISF<5> bit is set and the CVROE bit is set. Enabling the voltage reference output onto the RF5 pin, with an input signal present, will increase current consumption. Connecting RF5 as a digital output with VRSS enabled will also increase current consumption. The RF5 pin can be used as a simple D/A output with limited drive capability. Due to the limited current drive capability, a buffer must be used on the voltage reference output for external connections to VREF. Figure 21-2 shows an example buffering technique.
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PIC18FXX20
FIGURE 21-2: VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
CVREF Module
R(1)
RF5
+ -
Voltage Reference Output Impedance
CVREF Output
Note 1:
R is dependent upon the Voltage Reference Configuration bits CVRCON<3:0> and CVRCON<5>.
TABLE 21-1:
Name
REGISTERS ASSOCIATED WITH COMPARATOR VOLTAGE REFERENCE
Bit 6 Bit 5 CVRR C2INV Bit 4 CVRSS C1INV Bit 3 CVR3 CIS Bit 2 CVR2 CM2 TRISF2 Bit 1 CVR1 CM1 TRISF1 Bit 0 CVR0 CM0 Value on POR Value on all other RESETS
Bit 7
CVRCON CVREN CVROE CMCON TRISF C2OUT TRISF7 C1OUT
0000 0000 0000 0000 0000 0000 0000 0000
TRISF6 TRISF5 TRISF4 TRISF3
TRISF0 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented, read as `0'. Shaded cells are not used with the comparator voltage reference.
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NOTES:
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PIC18FXX20
22.0 LOW VOLTAGE DETECT
In many applications, the ability to determine if the device voltage (VDD) is below a specified voltage level is a desirable feature. A window of operation for the application can be created, where the application software can do "housekeeping tasks" before the device voltage exits the valid operating range. This can be done using the Low Voltage Detect module. This module is a software programmable circuitry, where a device voltage trip point can be specified. When the voltage of the device becomes lower then the specified point, an interrupt flag is set. If the interrupt is enabled, the program execution will branch to the interrupt vector address and the software can then respond to that interrupt source. The Low Voltage Detect circuitry is completely under software control. This allows the circuitry to be "turned off" by the software, which minimizes the current consumption for the device. Figure 22-1 shows a possible application voltage curve (typically for batteries). Over time, the device voltage decreases. When the device voltage equals voltage VA, the LVD logic generates an interrupt. This occurs at time TA. The application software then has the time, until the device voltage is no longer in valid operating range, to shut-down the system. Voltage point VB is the minimum valid operating voltage specification. This occurs at time TB. The difference TB - TA is the total time for shutdown.
FIGURE 22-1:
TYPICAL LOW VOLTAGE DETECT APPLICATION
Voltage
VA VB Legend: VA = LVD trip point VB = Minimum valid device operating voltage TA TB
Time
The block diagram for the LVD module is shown in Figure 22-2. A comparator uses an internally generated reference voltage as the set point. When the selected tap output of the device voltage crosses the set point (is lower than), the LVDIF bit is set. Each node in the resistor divider represents a "trip point" voltage. The "trip point" voltage is the minimum supply voltage level at which the device can operate before the LVD module asserts an interrupt. When the
supply voltage is equal to the trip point, the voltage tapped off of the resistor array is equal to the 1.2V internal reference voltage generated by the voltage reference module. The comparator then generates an interrupt signal setting the LVDIF bit. This voltage is software programmable to any one of 16 values (see Figure 22-2). The trip point is selected by programming the LVDL3:LVDL0 bits (LVDCON<3:0>).
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PIC18FXX20
FIGURE 22-2: LOW VOLTAGE DETECT (LVD) BLOCK DIAGRAM
VDD LVDIN LVD3:LVD0 LVDCON Register
16 to 1 MUX
LVDIF
LVDEN
Internally Generated Reference Voltage (Parameter #D423)
The LVD module has an additional feature that allows the user to supply the trip voltage to the module from an external source. This mode is enabled when bits LVDL3:LVDL0 are set to `1111'. In this state, the comparator input is multiplexed from the external input pin,
LVDIN (Figure 22-3). This gives users flexibility, because it allows them to configure the Low Voltage Detect interrupt to occur at any voltage in the valid operating range.
FIGURE 22-3:
LOW VOLTAGE DETECT (LVD) WITH EXTERNAL INPUT BLOCK DIAGRAM
VDD VDD LVD3:LVD0 LVDCON Register LVDEN LVD
LVDIN Externally Generated Trip Point
16 to 1 MUX
VxEN BODEN
EN BGAP
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PIC18FXX20
22.1 Control Register
The Low Voltage Detect Control register controls the operation of the Low Voltage Detect circuitry.
REGISTER 22-1:
LVDCON REGISTER
U-0 -- bit 7 U-0 -- R-0 IRVST R/W-0 LVDEN R/W-0 LVDL3 R/W-1 LVDL2 R/W-0 LVDL1 R/W-1 LVDL0 bit 0
bit 7-6 bit 5
Unimplemented: Read as '0' IRVST: Internal Reference Voltage Stable Flag bit 1 = Indicates that the Low Voltage Detect logic will generate the interrupt flag at the specified voltage range 0 = Indicates that the Low Voltage Detect logic will not generate the interrupt flag at the specified voltage range and the LVD interrupt should not be enabled LVDEN: Low Voltage Detect Power Enable bit 1 = Enables LVD, powers up LVD circuit 0 = Disables LVD, powers down LVD circuit LVDL3:LVDL0: Low Voltage Detection Limit bits 1111 = External analog input is used (input comes from the LVDIN pin) 1110 = 4.5V - 4.77V 1101 = 4.2V - 4.45V 1100 = 4.0V - 4.24V 1011 = 3.8V - 4.03V 1010 = 3.6V - 3.82V 1001 = 3.5V - 3.71V 1000 = 3.3V - 3.50V 0111 = 3.0V - 3.18V 0110 = 2.8V - 2.97V 0101 = 2.7V - 2.86V 0100 = 2.5V - 2.65V 0011 = 2.4V - 2.54V 0010 = 2.2V - 2.33V 0001 = 2.0V - 2.12V 0000 = Reserved Note: LVDL3:LVDL0 modes, which result in a trip point below the valid operating voltage of the device, are not tested.
bit 4
bit 3-0
Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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22.2 Operation
Depending on the power source for the device voltage, the voltage normally decreases relatively slowly. This means that the LVD module does not need to be constantly operating. To decrease the current requirements, the LVD circuitry only needs to be enabled for short periods, where the voltage is checked. After doing the check, the LVD module may be disabled. Each time that the LVD module is enabled, the circuitry requires some time to stabilize. After the circuitry has stabilized, all status flags may be cleared. The module will then indicate the proper state of the system. The following steps are needed to set up the LVD module: 1. Write the value to the LVDL3:LVDL0 bits (LVDCON register), which selects the desired LVD Trip Point. Ensure that LVD interrupts are disabled (the LVDIE bit is cleared or the GIE bit is cleared). Enable the LVD module (set the LVDEN bit in the LVDCON register). Wait for the LVD module to stabilize (the IRVST bit to become set). Clear the LVD interrupt flag, which may have falsely become set, until the LVD module has stabilized (clear the LVDIF bit). Enable the LVD interrupt (set the LVDIE and the GIE bits).
2. 3. 4. 5.
6.
Figure 22-4 shows typical waveforms that the LVD module may be used to detect.
FIGURE 22-4:
CASE 1: VDD
LOW VOLTAGE DETECT WAVEFORMS
LVDIF may not be set
VLVD LVDIF Enable LVD Internally Generated Reference Stable TIVRST LVDIF cleared in software
CASE 2: VDD VLVD LVDIF Enable LVD Internally Generated Reference Stable TIVRST
LVDIF cleared in software LVDIF cleared in software, LVDIF remains set since LVD condition still exists
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PIC18FXX20
22.2.1 REFERENCE VOLTAGE SET POINT
22.3
Operation During SLEEP
The Internal Reference Voltage of the LVD module, specified in electrical specification parameter #D423, may be used by other internal circuitry (the Programmable Brown-out Reset). If these circuits are disabled (lower current consumption), the reference voltage circuit requires a time to become stable before a low voltage condition can be reliably detected. This time is invariant of system clock speed. This start-up time is specified in electrical specification parameter #36. The low voltage interrupt flag will not be enabled until a stable reference voltage is reached. Refer to the waveform in Figure 22-4.
When enabled, the LVD circuitry continues to operate during SLEEP. If the device voltage crosses the trip point, the LVDIF bit will be set and the device will wake-up from SLEEP. Device execution will continue from the interrupt vector address if interrupts have been globally enabled.
22.4
Effects of a RESET
A device RESET forces all registers to their RESET state. This forces the LVD module to be turned off.
22.2.2
CURRENT CONSUMPTION
When the module is enabled, the LVD comparator and voltage divider are enabled and will consume static current. The voltage divider can be tapped from multiple places in the resistor array. Total current consumption, when enabled, is specified in electrical specification parameter #D022B.
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NOTES:
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PIC18FXX20
23.0 SPECIAL FEATURES OF THE CPU
23.1 Configuration Bits
There are several features intended to maximize system reliability, minimize cost through elimination of external components, provide power saving operating modes and offer code protection. These are: * Osc Selection * RESET - Power-on Reset (POR) - Power-up Timer (PWRT) - Oscillator Start-up Timer (OST) - Brown-out Reset (BOR) * Interrupts * Watchdog Timer (WDT) * SLEEP * Code Protection * ID Locations * In-Circuit Serial Programming All PIC18FXX20 devices have a Watchdog Timer, which is permanently enabled via the configuration bits, or software controlled. It runs off its own RC oscillator for added reliability. There are two timers that offer necessary delays on power-up. One is the Oscillator Start-up Timer (OST), intended to keep the chip in RESET until the crystal oscillator is stable. The other is the Power-up Timer (PWRT), which provides a fixed delay on power-up only, designed to keep the part in RESET while the power supply stabilizes. With these two timers on-chip, most applications need no external RESET circuitry. SLEEP mode is designed to offer a very low current power-down mode. The user can wake-up from SLEEP through external RESET, Watchdog Timer Wake-up, or through an interrupt. Several oscillator options are also made available to allow the part to fit the application. The RC oscillator option saves system cost, while the LP crystal option saves power. A set of configuration bits are used to select various options. The configuration bits can be programmed (read as '0'), or left unprogrammed (read as '1'), to select various device configurations. These bits are mapped, starting at program memory location 300000h. The user will note that address 300000h is beyond the user program memory space. In fact, it belongs to the configuration memory space (300000h through 3FFFFFh), which can only be accessed using Table Reads and Table Writes. Programming the configuration registers is done in a manner similar to programming the FLASH memory. The EECON1 register WR bit starts a self-timed write to the configuration register. In normal Operation mode, a TBLWT instruction with the TBLPTR pointed to the configuration register sets up the address and the data for the configuration register write. Setting the WR bit starts a long write to the configuration register. The configuration registers are written a byte at a time. To write or erase a configuration cell, a TBLWT instruction can write a `1' or a `0' into the cell.
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TABLE 23-1:
File Name 300001h 300002h 300003h 300005h 300006h 300008h 300009h 30000Ah 30000Bh 30000Ch 30000Dh CONFIG1H CONFIG2L CONFIG2H CONFIG3H CONFIG4L CONFIG5L CONFIG5H CONFIG6H CONFIG7H
CONFIGURATION BITS AND DEVICE IDS
Bit 7 -- -- -- WAIT -- DEBUG CP7(2) CPD WRTD -- DEV2 DEV10 Bit 6 -- -- -- -- -- -- CP6(2) CPB WRTB EBTRB DEV1 DEV9 Bit 5 OSCSEN -- -- -- -- -- CP5(2) -- WRT5(2) WRTC -- DEV0 DEV8 Bit 4 -- -- -- -- -- -- CP4(2) -- WRT4(2) -- -- REV4 DEV7 Bit 3 -- BORV1 WDTPS2 -- -- -- CP3 -- WRT3 -- EBTR3 -- REV3 DEV6 Bit 2 FOSC2 BORV0 WDTPS1 -- -- LVP CP2 -- WRT2 -- EBTR2 -- REV2 DEV5 Bit 1 FOSC1 BODEN WDTPS0 PM1 -- CP1 -- WRT1 -- EBTR1 -- REV1 DEV4 Bit 0 FOSC0 PWRTEN WDTEN PM0 STVREN CP0 -- WRT0 -- EBTR0 -- REV0 DEV3 Default/ Unprogrammed Value --1- -111 ---- 1111 ---- 1111 1--- --11 ---- --11 1--- -1-1 1111 1111 11-- ---1111 1111 111- ---1111 1111 -1-- ---(4) 0000 0110
300004h(1) CONFIG3L
T1OSCMX(3) CCP2MX
CONFIG6L WRT7(2) WRT6(2)
CONFIG7L EBTR7(2) EBTR6(2) EBTR5(2) EBTR4(2)
3FFFFEh DEVID1 3FFFFFh DEVID2
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Shaded cells are unimplemented, read as `0'. Note 1: 2: 3: 4: Unimplemented in PIC18F6X20 devices; maintain this bit set. Unimplemented in PIC18FX520 and PIC18FX620 devices; maintain this bit set. Unimplemented in PIC18FX620 and PIC18FX720 devices; maintain this bit set. See Register 23-13 for DEVID1 values.
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PIC18FXX20
REGISTER 23-1: CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
U-0 -- bit 7 bit 7-6 bit 5 Unimplemented: Read as `0' OSCSEN: Oscillator System Clock Switch Enable bit 1 = Oscillator system clock switch option is disabled (main oscillator is source) 0 = Timer1 Oscillator system clock switch option is enabled (oscillator switching is enabled) Unimplemented: Read as `0' FOSC2:FOSC0: Oscillator Selection bits 111 = RC oscillator w/ OSC2 configured as RA6 110 = HS oscillator with PLL enabled; clock frequency = (4 x FOSC) 101 = EC oscillator w/ OSC2 configured as RA6 100 = EC oscillator w/ OSC2 configured as divide-by-4 clock output 011 = RC oscillator w/ OSC2 configured as divide-by-4 clock output 010 = HS oscillator 001 = XT oscillator 000 = LP oscillator Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed U-0 -- R/P-1 OSCSEN U-0 -- U-0 -- R/P-1 FOSC2 R/P-1 FOSC1 R/P-1 FOSC0 bit 0
bit 4-3 bit 2-0
REGISTER 23-2:
CONFIG2L: CONFIGURATION REGISTER 2 LOW (BYTE ADDRESS 300002h)
U-0 -- bit 7 U-0 -- U-0 -- U-0 -- R/P-1 BORV1 R/P-1 BORV0 R/P-1 BOREN R/P-1 PWRTEN bit 0
bit 7-4 bit 3-2
Unimplemented: Read as `0' BORV1:BORV0: Brown-out Reset Voltage bits 11 = VBOR set to 2.5V 10 = VBOR set to 2.7V 01 = VBOR set to 4.2V 00 = VBOR set to 4.5V BOREN: Brown-out Reset Enable bit 1 = Brown-out Reset enabled 0 = Brown-out Reset disabled PWRTEN: Power-up Timer Enable bit 1 = PWRT disabled 0 = PWRT enabled Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed
bit 1
bit 0
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REGISTER 23-3: CONFIG2H: CONFIGURATION REGISTER 2 HIGH (BYTE ADDRESS 300003h)
U-0 -- bit 7 bit 7-4 bit 3-1 Unimplemented: Read as `0' WDTPS2:WDTPS0: Watchdog Timer Postscale Select bits 111 = 1:128 110 = 1:64 101 = 1:32 100 = 1:16 011 = 1:8 010 = 1:4 001 = 1:2 000 = 1:1 WDTEN: Watchdog Timer Enable bit 1 = WDT enabled 0 = WDT disabled (control is placed on the SWDTEN bit) Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed U-0 -- U-0 -- U-0 -- R/P-1 WDTPS2 R/P-1 WDTPS1 R/P-1 WDTPS0 R/P-1 WDTEN bit 0
bit 0
REGISTER 23-4:
CONFIG3L: CONFIGURATION REGISTER 3 LOW (BYTE ADDRESS 300004h)(1)
R/P-1 WAIT bit 7 U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- R/P-1 PM1 R/P-1 PM0 bit 0
bit 7
WAIT: External Bus Data Wait Enable bit 1 = Wait selections unavailable for Table Reads and Table Writes 0 = Wait selections for Table Reads and Table Writes are determined by WAIT1:WAIT0 bits (MEMCOM<5:4>) Unimplemented: Read as `0' PM1:PM0: Processor Mode Select bits 11 = Microcontroller mode 10 = Microprocessor mode 01 = Microprocessor with Boot Block mode 00 = Extended Microcontroller mode Note 1: Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed This register is unimplemented in PIC18F6X20 devices; maintain these bits set.
bit 6-2 bit 1-0
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PIC18FXX20
REGISTER 23-5: CONFIG3H: CONFIGURATION REGISTER 3 HIGH (BYTE ADDRESS 300005h)
U-0 -- bit 7 bit 7-2 bit 1 Unimplemented: Read as `0' T1OSCMX: Timer1 Oscillator Mode bit(1) 1 = Standard (legacy) Timer1 oscillator operation 0 = Low power Timer1 operation when microcontroller is in SLEEP mode CCP2MX: CCP2 Mux bit In Microcontroller mode: 1 = CCP2 input/output is multiplexed with RC1 0 = CCP2 input/output is multiplexed with RE7 In Microprocessor, Microprocessor with Boot Block and Extended Microcontroller modes (PIC18F8X20 devices only): 1 = CCP2 input/output is multiplexed with RC1 0 = CCP2 input/output is multiplexed with RB3 Note 1: Unimplemented in PIC18FX620 and PIC18FX720 devices; maintain this bit set. Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- R/P-1 T1OSCMX
(1)
R/P-1 CCP2MX bit 0
bit 0
REGISTER 23-6:
CONFIG4L: CONFIGURATION REGISTER 4 LOW (BYTE ADDRESS 300006h)
R/P-1 DEBUG bit 7 U-0 -- U-0 -- U-0 -- U-0 -- R/P-1 LVP U-0 -- R/P-1 STVREN bit 0
bit 7
DEBUG: Background Debugger Enable bit 1 = Background Debugger disabled. RB6 and RB7 configured as general purpose I/O pins. 0 = Background Debugger enabled. RB6 and RB7 are dedicated to In-Circuit Debug. Unimplemented: Read as `0' LVP: Low Voltage ICSP Enable bit 1 = Low Voltage ICSP enabled 0 = Low Voltage ICSP disabled Unimplemented: Read as `0' STVREN: Stack Full/Underflow Reset Enable bit 1 = Stack Full/Underflow will cause RESET 0 = Stack Full/Underflow will not cause RESET Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed
bit 6-3 bit 2
bit 1 bit 0
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REGISTER 23-7: CONFIG5L: CONFIGURATION REGISTER 5 LOW (BYTE ADDRESS 300008h)
R/P-1 CP7(1) bit 7 bit 7 CP7: Code Protection bit(1) 1 = Block 7 (01C000-01FFFFh) not code protected 0 = Block 7 (01C000-01FFFFh) code protected CP6: Code Protection bit(1) 1 = Block 6 (018000-01BFFFh) not code protected 0 = Block 6 (018000-01BFFFh) code protected CP5: Code Protection bit(1) 1 = Block 5 (014000-017FFFh) not code protected 0 = Block 5 (014000-017FFFh) code protected CP4: Code Protection bit(1) 1 = Block 4 (010000-013FFFh) not code protected 0 = Block 4 (010000-013FFFh) code protected CP3: Code Protection bit For PIC18FX520 devices: 1 = Block 3 (006000-007FFFh) not code protected 0 = Block 3 (006000-007FFFh) code protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 3 (00C000-00FFFFh) not code protected 0 = Block 3 (00C000-00FFFFh) code protected CP2: Code Protection bit For PIC18FX520 devices: 1 = Block 2 (004000-005FFFh) not code protected 0 = Block 2 (004000-005FFFh) code protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 2 (008000-00BFFFh) not code protected 0 = Block 2 (008000-00BFFFh) code protected CP1: Code Protection bit For PIC18FX520 devices: 1 = Block 1 (002000-003FFFh) not code protected 0 = Block 1 (002000-003FFFh) code protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 1 (004000-007FFFh) not code protected 0 = Block 1 (004000-007FFFh) code protected CP0: Code Protection bit For PIC18FX520 devices: 1 = Block 0 (000800-001FFFh) not code protected 0 = Block 0 (000800-001FFFh) code protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 0 (000200-003FFFh) not code protected 0 = Block 0 (000200-003FFFh) code protected Note 1: Unimplemented in PIC18FX520 and PIC18FX620 devices; maintain this bit set. Legend: R = Readable bit P = Programmable bit - n = Value when device is unprogrammed R/P-1 CP6(1) R/P-1 CP5(1) R/P-1 CP4(1) R/P-1 CP3 R/P-1 CP2 R/P-1 CP1 R/P-1 CP0 bit 0
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
U = Unimplemented bit, read as `0' u = Unchanged from programmed state
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PIC18FXX20
REGISTER 23-8: CONFIG5H: CONFIGURATION REGISTER 5 HIGH (BYTE ADDRESS 300009h)
R/C-1 CPD bit 7 bit 7 R/C-1 CPB U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- bit 0
bit 6
bit 5-0
CPD: Data EEPROM Code Protection bit 1 = Data EEPROM not code protected 0 = Data EEPROM code protected CPB: Boot Block Code Protection bit For PIC18FX520 devices: 1 = Boot Block (000000-0007FFh) not code protected 0 = Boot Block (000000-0007FFh) code protected For PIC18FX620 and PIC18FX720 devices: 1 = Boot Block (000000-0001FFh) not code protected 0 = Boot Block (000000-0001FFh) code protected Unimplemented: Read as `0' Legend: R = Readable bit C = Clearable bit - n = Value when device is unprogrammed
U = Unimplemented bit, read as `0' u = Unchanged from programmed state
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PIC18FXX20
REGISTER 23-9: CONFIG6L: CONFIGURATION REGISTER 6 LOW (BYTE ADDRESS 30000Ah)
R/P-1 WRT7(1) bit 7 bit 7 WR7: Write Protection bit(1) 1 = Block 7 (01C000-01FFFFh) not write protected 0 = Block 7 (01C000-01FFFFh) write protected WR6: Write Protection bit(1) 1 = Block 6 (018000-01BFFFh) not write protected 0 = Block 6 (018000-01BFFFh) write protected WR5: Write Protection bit(1) 1 = Block 5 (014000-017FFFh) not write protected 0 = Block 5 (014000-017FFFh) write protected WR4: Write Protection bit(1) 1 = Block 4 (010000-013FFFh) not write protected 0 = Block 4 (010000-013FFFh) write protected WR3: Write Protection bit For PIC18FX520 devices: 1 = Block 3 (006000-007FFFh) not write protected 0 = Block 3 (006000-007FFFh) write protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 3 (00C000-00FFFFh) not write protected 0 = Block 3 (00C000-00FFFFh) write protected WR2: Write Protection bit For PIC18FX520 devices: 1 = Block 2 (004000-005FFFh) not write protected 0 = Block 2 (004000-005FFFh) write protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 2 (008000-00BFFFh) not write protected 0 = Block 2 (008000-00BFFFh) write protected WR1: Write Protection bit For PIC18FX520 devices: 1 = Block 1 (002000-003FFFh) not write protected 0 = Block 1 (002000-003FFFh) write protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 1 (004000-007FFFh) not write protected 0 = Block 1 (004000-007FFFh) write protected WR0: Write Protection bit For PIC18FX520 devices: 1 = Block 0 (000800-001FFFh) not write protected 0 = Block 0 (000800-001FFFh) write protected For PIC18FX620 and PIC18FX720 devices: 1 = Block 0 (000200-003FFFh) not write protected 0 = Block 0 (000200-003FFFh) write protected Note 1: Unimplemented in PIC18FX520 and PIC18FX620 devices; maintain this bit set. Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed R/P-1 WRT6(1) R/P-1 WRT5(1) R/P-1 WRT4(1) R/P-1 WRT3 R/P-1 WRT2 R/P-1 WRT1 R/P-1 WRT0 bit 0
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 23-10: CONFIG6H: CONFIGURATION REGISTER 6 HIGH (BYTE ADDRESS 30000Bh)
R/P-1 WRTD bit 7 bit 7 WRTD: Data EEPROM Write Protection bit 1 = Data EEPROM not write protected 0 = Data EEPROM write protected WRTB: Boot Block Write Protection bit For PIC18FX520 devices: 1 = Boot Block (000000-0007FFh) not write protected 0 = Boot Block (000000-0007FFh) write protected For PIC18FX620 and PIC18FX720 devices: 1 = Boot Block (000000-0001FFh) not write protected 0 = Boot Block (000000-0001FFh) write protected WRTC: Configuration Register Write Protection bit(1) 1 = Configuration registers (300000-3000FFh) not write protected 0 = Configuration registers (300000-3000FFh) write protected Note 1: This bit is read only, and cannot be changed in User mode. bit 4-0 Unimplemented: Read as `0' Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed R/P-1 WRTB R-1 WRTC
(1)
U-0 --
U-0 --
U-0 --
U-0 --
U-0 -- bit 0
bit 6
bit 5
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REGISTER 23-11: CONFIG7L: CONFIGURATION REGISTER 7 LOW (BYTE ADDRESS 30000Ch)
R/P-1 EBTR7 bit 7 bit 7 EBTR7: Table Read Protection bit(1) 1 = Block 3 (01C000-01FFFFh) not protected from Table Reads executed in other blocks 0 = Block 3 (01C000-01FFFFh) protected from Table Reads executed in other blocks EBTR6: Table Read Protection bit(1) 1 = Block 2 (018000-01BFFFh) not protected from Table Reads executed in other blocks 0 = Block 2 (018000-01BFFFh) protected from Table Reads executed in other blocks EBTR5: Table Read Protection bit(1) 1 = Block 1 (014000-017FFFh) not protected from Table Reads executed in other blocks 0 = Block 1 (014000-017FFFh) protected from Table Reads executed in other blocks EBTR4: Table Read Protection bit(1) 1 = Block 0 (010000-013FFFh) not protected from Table Reads executed in other blocks 0 = Block 0 (010000-013FFFh) protected from Table Reads executed in other blocks EBTR3: Table Read Protection bit For PIC18FX520 devices: 1 = Block 3 (006000-007FFFh) not protected from Table Reads executed in other blocks 0 = Block 3 (006000-007FFFh) protected from Table Reads executed in other blocks For PIC18FX620 and PIC18FX720 devices: 1 = Block 3 (00C000-00FFFFh) not protected from Table Reads executed in other blocks 0 = Block 3 (00C000-00FFFFh) protected from Table Reads executed in other blocks EBTR2: Table Read Protection bit For PIC18FX520 devices: 1 = Block 2 (004000-005FFFh) not protected from Table Reads executed in other blocks 0 = Block 2 (004000-005FFFh) protected from Table Reads executed in other blocks For PIC18FX620 and PIC18FX720 devices: 1 = Block 2 (008000-00BFFFh) not protected from Table Reads executed in other blocks 0 = Block 2 (008000-00BFFFh) protected from Table Reads executed in other blocks EBTR1: Table Read Protection bit For PIC18FX520 devices: 1 = Block 1 (002000-003FFFh) not protected from Table Reads executed in other blocks 0 = Block 1 (002000-003FFFh) protected from Table Reads executed in other blocks For PIC18FX620 and PIC18FX720 devices: 1 = Block 1 (004000-007FFFh) not protected from Table Reads executed in other blocks 0 = Block 1 (004000-007FFFh) protected from Table Reads executed in other blocks EBTR0: Table Read Protection bit For PIC18FX520 devices: 1 = Block 0 (000800-001FFFh) not protected from Table Reads executed in other blocks 0 = Block 0 (000800-001FFFh) protected from Table Reads executed in other blocks For PIC18FX620 and PIC18FX720 devices: 1 = Block 0 (000200-003FFFh) not protected from Table Reads executed in other blocks 0 = Block 0 (000200-003FFFh) protected from Table Reads executed in other blocks Note 1: Unimplemented in PIC18FX520 and PIC18FX620 devices; maintain this bit set. Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed
(1)
R/P-1 EBTR6
(1)
R/P-1 EBTR5
(1)
R/P-1 EBTR4
(1)
R/P-1 EBTR3
R/P-1 EBTR2
R/P-1 EBTR1
R/P-1 EBTR0 bit 0
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
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REGISTER 23-12: CONFIG7H: CONFIGURATION REGISTER 7 HIGH (BYTE ADDRESS 30000Dh)
U-0 -- bit 7 bit 7 bit 6 Unimplemented: Read as `0' EBTRB: Boot Block Table Read Protection bit For PIC18FX520 devices: 1 = Boot Block (000000-0007FFh) not protected from Table Reads executed in other blocks 0 = Boot Block (000000-0007FFh) protected from Table Reads executed in other blocks For PIC18FX620 and PIC18FX720 devices: 1 = Boot Block (000000-0001FFh) not protected from Table Reads executed in other blocks 0 = Boot Block (000000-0001FFh) protected from Table Reads executed in other blocks Unimplemented: Read as `0' Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed R/P-1 EBTRB U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- bit 0
bit 5-0
REGISTER 23-13: DEVICE ID REGISTER 1 FOR PIC18FXX20 DEVICES (ADDRESS 3FFFFEh)
R DEV2 bit 7 bit 7-5 DEV2:DEV0: Device ID bits 000 = PIC18F8720 001 = PIC18F6720 010 = PIC18F8620 011 = PIC18F6620 REV4:REV0: Revision ID bits These bits are used to indicate the device revision Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed R DEV1 R DEV0 R REV4 R REV3 R REV2 R REV1 R REV0 bit 0
bit 4-0
REGISTER 23-14: DEVICE ID REGISTER 2 FOR PIC18FXX20 DEVICES (ADDRESS 3FFFFFh)
R DEV10 bit 7 bit 7-0 DEV10:DEV3: Device ID bits These bits are used with the DEV2:DEV0 bits in the Device ID Register 1 to identify the part number Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as `0' u = Unchanged from programmed state - n = Value when device is unprogrammed R DEV9 R DEV8 R DEV7 R DEV6 R DEV5 R DEV4 R DEV3 bit 0
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23.2 Watchdog Timer (WDT)
The Watchdog Timer is a free running, on-chip RC oscillator, which does not require any external components. This RC oscillator is separate from the RC oscillator of the OSC1/CLKI pin. That means that the WDT will run, even if the clock on the OSC1/CLKI and OSC2/CLKO/RA6 pins of the device has been stopped, for example, by execution of a SLEEP instruction. During normal operation, a WDT time-out generates a device RESET (Watchdog Timer Reset). If the device is in SLEEP mode, a WDT time-out causes the device to wake-up and continue with normal operation (Watchdog Timer Wake-up). The TO bit in the RCON register will be cleared upon a WDT time-out. The Watchdog Timer is enabled/disabled by a device configuration bit. If the WDT is enabled, software execution may not disable this function. When the WDTEN configuration bit is cleared, the SWDTEN bit enables/disables the operation of the WDT. The WDT time-out period values may be found in the Electrical Specifications section under parameter #31. Values for the WDT postscaler may be assigned using the configuration bits. Note 1: The CLRWDT and SLEEP instructions clear the WDT and the postscaler, if assigned to the WDT and prevent it from timing out and generating a device RESET condition. 2: When a CLRWDT instruction is executed and the postscaler is assigned to the WDT, the postscaler count will be cleared, but the postscaler assignment is not changed.
23.2.1
CONTROL REGISTER
Register 23-15 shows the WDTCON register. This is a readable and writable register, which contains a control bit that allows software to override the WDT enable configuration bit, only when the configuration bit has disabled the WDT.
REGISTER 23-15: WDTCON REGISTER
U-0 -- bit 7 bit 7-1 bit 0 Unimplemented: Read as `0' SWDTEN: Software Controlled Watchdog Timer Enable bit 1 = Watchdog Timer is on 0 = Watchdog Timer is turned off if the WDTEN configuration bit in the Configuration register = 0 Legend: R = Readable bit - n = Value at POR W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- U-0 -- R/W-0 SWDTEN bit 0
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23.2.2 WDT POSTSCALER
The WDT has a postscaler that can extend the WDT Reset period. The postscaler is selected at the time of the device programming, by the value written to the CONFIG2H configuration register.
FIGURE 23-1:
WATCHDOG TIMER BLOCK DIAGRAM
WDT Timer
Postscaler 8 8 - to - 1 MUX WDTPS2:WDTPS0
WDTEN Configuration bit
SWDTEN bit
WDT Time-out Note: WDPS2:WDPS0 are bits in register CONFIG2H.
TABLE 23-2:
Name CONFIG2H RCON WDTCON
SUMMARY OF WATCHDOG TIMER REGISTERS
Bit 7 -- IPEN -- Bit 6 -- -- -- Bit 5 -- -- -- Bit 4 -- RI -- Bit 3 WDTPS2 TO -- Bit 2 WDTPS2 PD -- Bit 1 WDTPS0 POR -- Bit 0 WDTEN BOR SWDTEN
Legend: Shaded cells are not used by the Watchdog Timer.
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23.3 Power-down Mode (SLEEP)
Power-down mode is entered by executing a SLEEP instruction. If enabled, the Watchdog Timer will be cleared, but keeps running, the PD bit (RCON<3>) is cleared, the TO (RCON<4>) bit is set, and the oscillator driver is turned off. The I/O ports maintain the status they had before the SLEEP instruction was executed (driving high, low, or hi-impedance). For lowest current consumption in this mode, place all I/O pins at either VDD or VSS, ensure no external circuitry is drawing current from the I/O pin, power-down the A/D and disable external clocks. Pull all I/O pins that are hi-impedance inputs, high or low externally, to avoid switching currents caused by floating inputs. The T0CKI input should also be at VDD or VSS for lowest current consumption. The contribution from on-chip pull-ups on PORTB should be considered. The MCLR pin must be at a logic high level (VIHMC). External MCLR Reset will cause a device RESET. All other events are considered a continuation of program execution and will cause a "wake-up". The TO and PD bits in the RCON register can be used to determine the cause of the device RESET. The PD bit, which is set on power-up, is cleared when SLEEP is invoked. The TO bit is cleared if a WDT time-out occurred (and caused wake-up). When the SLEEP instruction is being executed, the next instruction (PC + 2) is pre-fetched. For the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). Wake-up is regardless of the state of the GIE bit. If the GIE bit is clear (disabled), the device continues execution at the instruction after the SLEEP instruction. If the GIE bit is set (enabled), the device executes the instruction after the SLEEP instruction and then branches to the interrupt address. In cases where the execution of the instruction following SLEEP is not desirable, the user should have a NOP after the SLEEP instruction.
23.3.1
WAKE-UP FROM SLEEP
23.3.2
WAKE-UP USING INTERRUPTS
The device can wake-up from SLEEP through one of the following events: 1. 2. 3. External RESET input on MCLR pin. Watchdog Timer Wake-up (if WDT was enabled). Interrupt from INT pin, RB port change or a peripheral interrupt.
When global interrupts are disabled (GIE cleared) and any interrupt source has both its interrupt enable bit and interrupt flag bit set, one of the following will occur: * If an interrupt condition (interrupt flag bit and interrupt enable bits are set) occurs before the execution of a SLEEP instruction, the SLEEP instruction will complete as a NOP. Therefore, the WDT and WDT postscaler will not be cleared, the TO bit will not be set and PD bits will not be cleared. * If the interrupt condition occurs during or after the execution of a SLEEP instruction, the device will immediately wake-up from SLEEP. The SLEEP instruction will be completely executed before the wake-up. Therefore, the WDT and WDT postscaler will be cleared, the TO bit will be set and the PD bit will be cleared. Even if the flag bits were checked before executing a SLEEP instruction, it may be possible for flag bits to become set before the SLEEP instruction completes. To determine whether a SLEEP instruction executed, test the PD bit. If the PD bit is set, the SLEEP instruction was executed as a NOP. To ensure that the WDT is cleared, a CLRWDT instruction should be executed before a SLEEP instruction.
The following peripheral interrupts can wake the device from SLEEP: PSP read or write. TMR1 interrupt. Timer1 must be operating as an asynchronous counter. 3. TMR3 interrupt. Timer3 must be operating as an asynchronous counter. 4. CCP Capture mode interrupt. 5. Special event trigger (Timer1 in Asynchronous mode using an external clock). 6. MSSP (START/STOP) bit detect interrupt. 7. MSSP transmit or receive in Slave mode (SPI/I2C). 8. USART RX or TX (Synchronous Slave mode). 9. A/D conversion (when A/D clock source is RC). 10. EEPROM write operation complete. 11. LVD interrupt. Other peripherals cannot generate interrupts, since during SLEEP, no on-chip clocks are present. 1. 2.
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PIC18FXX20
FIGURE 23-2:
OSC1 CLKO(4) INT pin INTF flag (INTCON<1>) GIEH bit (INTCON<7>) INSTRUCTION FLOW PC Instruction Fetched Instruction Executed Note 1: 2: 3: 4: PC Inst(PC) = SLEEP Inst(PC - 1) PC+2 Inst(PC + 2) SLEEP PC+4 PC+4 Inst(PC + 4) Inst(PC + 2) Dummy Cycle PC + 4 0008h Inst(0008h) Dummy Cycle 000Ah Inst(000Ah) Inst(0008h) Processor in SLEEP Interrupt Latency(3) TOST(2)
WAKE-UP FROM SLEEP THROUGH INTERRUPT(1,2)
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
XT, HS or LP Oscillator mode assumed. GIE = 1 assumed. In this case, after wake-up, the processor jumps to the interrupt routine. If GIE = 0, execution will continue in-line. TOST = 1024 TOSC (drawing not to scale). This delay will not occur for RC and EC Osc modes. CLKO is not available in these Osc modes, but shown here for timing reference.
23.4
Program Verification and Code Protection
The overall structure of the code protection on the PIC18 FLASH devices differs significantly from other PICmicro devices. The user program memory is divided on binary boundaries into individual blocks, each of which has three separate code protection bits associated with it: * Code Protect bit (CPn) * Write Protect bit (WRTn) * External Block Table Read bit (EBTRn) The code protection bits are located in Configuration Registers 5L through 7H. Their locations within the registers are summarized in Table 23-3.
In the PIC18FXX20 family, the block size varies with the size of the user program memory. For PIC18FX520 devices, program memory is divided into four blocks of 8 Kbytes each. The first block is further divided into a boot block of 2 Kbytes and a second block (Block 0) of 6 Kbytes, for a total of five blocks. The organization of the blocks and their associated code protection bits are shown in Figure 23-3. For PIC18FX620 and PIC18FX720 devices, program memory is divided into blocks of 16 Kbytes. The first block is further divided into a boot block of 512 bytes and a second block (Block 0) of 15.5 Kbytes, for a total of nine blocks. This produces five blocks for 64-Kbyte devices, and nine for 128-Kbyte devices. The organization of the blocks and their associated code protection bits are shown in Figure 23-4.
TABLE 23-3:
SUMMARY OF CODE PROTECTION REGISTERS
Bit 7 CP7* CPD WRT7* WRTD EBTR7* -- Bit 6 CP6* CPB WRT6* WRTB EBTR6* EBTRB Bit 5 CP5* -- WRT5* WRTC EBTR5* -- Bit 4 CP4* -- WRT4* -- EBTR4* -- Bit 3 CP3 -- WRT3 -- EBTR3 -- Bit 2 CP2 -- WRT2 -- EBTR2 -- Bit 1 CP1 -- WRT1 -- EBTR1 -- Bit 0 CP0 -- WRT0 -- EBTR0 --
File Name 300008h 300009h 30000Ah 30000Bh 30000Ch 30000Dh CONFIG5L CONFIG5H CONFIG6L CONFIG6H CONFIG7L CONFIG7H
Legend: Shaded cells are unimplemented. * Unimplemented in PIC18FX520 and PIC18FX620 devices.
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FIGURE 23-3: CODE PROTECTED PROGRAM MEMORY FOR PIC18FX520 DEVICES
32 Kbytes Boot Block Block 0 Block 1 003FFFh 004000h Block 2 005FFFh 006000h Block 3 007FFFh 008000h CP3, WRT3, EBTR3 CP2, WRT2, EBTR2 Address Range 000000h 0007FFh 000800h 001FFFh 002000h CP1, WRT1, EBTR1 Block Code Protection Controlled By: CPB, WRTB, EBTRB CP0, WRT0, EBTR0
Unimplemented Read `0's
1FFFFFh
FIGURE 23-4:
CODE PROTECTED PROGRAM MEMORY FOR PIC18FX620/X720 DEVICES
MEMORY SIZE / DEVICE Block Code Protection Controlled By: CPB, WRTB, EBTRB CP0, WRT0, EBTR0 CP1, WRT1, EBTR1 007FFFh 008000h
64 Kbytes (PIC18FX620) Boot Block Block 0 Block 1
128 Kbytes (PIC18FX720) Boot Block Block 0 Block 1
Address Range 000000h 0001FFh 000200h 003FFFh 004000h
Block 2
Block 2 00BFFFh 00C000h
CP2, WRT2, EBTR2
Block 3
Block 3 00FFFFh 010000h Block 4 013FFFh 014000h Block 5
CP3, WRT3, EBTR3
CP4, WRT4, EBTR4
CP5, WRT5, EBTR5 017FFFh 018000h
Unimplemented Read `0's Block 6
CP6, WRT6, EBTR6 01BFFFh 01C000h
Block 7 01FFFFh
CP7, WRT7, EBTR7
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23.4.1 PROGRAM MEMORY CODE PROTECTION
The user memory may be read to, or written from, any location using the Table Read and Table Write instructions. The device ID may be read with Table Reads. The configuration registers may be read and written with the Table Read and Table Write instructions. In User mode, the CPn bits have no direct effect. CPn bits inhibit external reads and writes. A block of user memory may be protected from Table Writes if the WRTn configuration bit is `0'. The EBTRn bits control Table Reads. For a block of user memory with the EBTRn bit set to `0', a Table Read instruction that executes from within that block is allowed to read. A Table Read instruction that executes from a location outside of that block is not allowed to read, and will result in reading `0's. Figures 23-5 through 23-7 illustrate Table Write and Table Read protection, using devices with a 16-Kbyte block size as the models. The principles illustrated are identical for devices with an 8-Kbyte block size. Note: Code protection bits may only be written to a `0' from a `1' state. It is not possible to write a `1' to a bit in the `0' state. Code protection bits are only set to `1' by a full chip erase or block erase function. The full chip erase and block erase functions can only be initiated via ICSP or an external programmer.
FIGURE 23-5:
TABLE WRITE (WRTn) DISALLOWED
Program Memory 000000h 0001FFh 000200h TBLWT * 003FFFh 004000h WRT1,EBTR1 = 11 007FFFh 008000h Configuration Bit Settings WRTB,EBTRB = 11 WRT0,EBTR0 = 01
Register Values
TBLPTR = 000FFFh PC = 003FFEh
PC = 008FFEh
TBLWT * 00BFFFh 00C000h
WRT2,EBTR2 = 11
WRT3,EBTR3 = 11 00FFFFh
Results: All Table Writes disabled to Block n whenever WRTn = 0.
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FIGURE 23-6: EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Program Memory 000000h 0001FFh 000200h TBLPTR = 000FFFh 003FFFh 004000h PC = 004FFEh TBLRD * 007FFFh 008000h WRT2,EBTR2 = 11 00BFFFh 00C000h WRT3,EBTR3 = 11 00FFFFh WRT1,EBTR1 = 11 Configuration Bit Settings WRTB,EBTRB = 11 WRT0,EBTR0 = 10 Register Values
Results: All Table Reads from external blocks to Block n are disabled whenever EBTRn = 0. TABLAT register returns a value of `0'.
FIGURE 23-7:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Program Memory 000000h 0001FFh 000200h TBLRD * 003FFFh 004000h WRT1,EBTR1 = 11 007FFFh 008000h WRT2,EBTR2 = 11 00BFFFh 00C000h WRT3,EBTR3 = 11 00FFFFh Configuration Bit Settings WRTB,EBTRB = 11 WRT0,EBTR0 = 10
Register Values
TBLPTR = 000FFFh PC = 003FFEh
Results: Table Reads permitted within Block n, even when EBTRBn = 0. TABLAT register returns the value of the data at the location TBLPTR.
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23.4.2 DATA EEPROM CODE PROTECTION TABLE 23-4: DEBUGGER RESOURCES
RB6, RB7 2 levels Last 576 bytes Last 10 bytes The entire Data EEPROM is protected from external reads and writes by two bits: CPD and WRTD. CPD inhibits external reads and writes of Data EEPROM. WRTD inhibits external writes to Data EEPROM. The CPU can continue to read and write Data EEPROM, regardless of the protection bit settings. I/O pins Stack Program Memory Data Memory
23.4.3
CONFIGURATION REGISTER PROTECTION
The configuration registers can be write protected. The WRTC bit controls protection of the Configuration registers. In User mode, the WRTC bit is readable only. WRTC can only be written via ICSP or an external programmer.
To use the In-Circuit Debugger function of the microcontroller, the design must implement In-Circuit Serial Programming connections to MCLR/VPP, VDD, GND, RB7 and RB6. This will interface to the In-Circuit Debugger module available from Microchip, or one of the third party development tool companies.
23.8
Low Voltage ICSP Programming
23.5
ID Locations
Eight memory locations (200000h - 200007h) are designated as ID locations, where the user can store checksum or other code identification numbers. These locations are accessible during normal execution through the TBLRD and TBLWT instructions, or during program/verify. The ID locations can be read when the device is code protected.
The LVP bit Configuration register, CONFIG4L, enables low voltage ICSP programming. This mode allows the microcontroller to be programmed via ICSP using a VDD source in the operating voltage range. This only means that VPP does not have to be brought to VIHH, but can instead be left at the normal operating voltage. In this mode, the RB5/PGM pin is dedicated to the programming function and ceases to be a general purpose I/O pin. During programming, VDD is applied to the MCLR/VPP pin. To enter Programming mode, VDD must be applied to the RB5/PGM, provided the LVP bit is set. The LVP bit defaults to a (`1') from the factory. Note 1: The High Voltage Programming mode is always available, regardless of the state of the LVP bit, by applying VIHH to the MCLR pin. 2: While in Low Voltage ICSP mode, the RB5 pin can no longer be used as a general purpose I/O pin, and should be held low during normal operation. 3: When using low voltage ICSP programming (LVP) and the pull-ups on PORTB are enabled, bit 5 in the TRISB register must be cleared to disable the pull-up on RB5 and ensure the proper operation of the device. If Low Voltage Programming mode is not used, the LVP bit can be programmed to a '0' and RB5/PGM becomes a digital I/O pin. However, the LVP bit may only be programmed when programming is entered with VIHH on MCLR/VPP. It should be noted that once the LVP bit is programmed to `0', only the High Voltage Programming mode is available and only High Voltage Programming mode can be used to program the device. When using low voltage ICSP, the part must be supplied 4.5V to 5.5V, if a bulk erase will be executed. This includes reprogramming of the code protect bits from an on state to an off state. For all other cases of low voltage ICSP, the part may be programmed at the normal operating voltage. This means unique user IDs, or user code can be reprogrammed or added.
23.6
In-Circuit Serial Programming
PIC18FXX20 microcontrollers can be serially programmed while in the end application circuit. This is simply done with two lines for clock and data, and three other lines for power, ground and the programming voltage. This allows customers to manufacture boards with unprogrammed devices, and then program the microcontroller just before shipping the product. This also allows the most recent firmware, or a custom firmware to be programmed. Note: When performing in-circuit serial programming, verify that power is connected to all VDD and AVDD pins of the microcontroller, and that all VSS and AVSS pins are grounded.
23.7
In-Circuit Debugger
When the DEBUG bit in Configuration register CONFIG4L is programmed to a '0', the In-Circuit Debugger functionality is enabled. This function allows simple debugging functions when used with MPLAB(R) IDE. When the microcontroller has this feature enabled, some of the resources are not available for general use. Table 23-4 shows which features are consumed by the background debugger.
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NOTES:
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PIC18FXX20
24.0 INSTRUCTION SET SUMMARY
The PIC18 instruction set adds many enhancements to the previous PICmicro instruction sets, while maintaining an easy migration from these PICmicro instruction sets. Most instructions are a single program memory word (16 bits), but there are three instructions that require two program memory locations. Each single word instruction is a 16-bit word divided into an OPCODE, which specifies the instruction type and one or more operands, which further specify the operation of the instruction. The instruction set is highly orthogonal and is grouped into four basic categories: * * * * Byte-oriented operations Bit-oriented operations Literal operations Control operations The literal instructions may use some of the following operands: * A literal value to be loaded into a file register (specified by `k') * The desired FSR register to load the literal value into (specified by `f') * No operand required (specified by `--') The control instructions may use some of the following operands: * A program memory address (specified by `n') * The mode of the Call or Return instructions (specified by `s') * The mode of the Table Read and Table Write instructions (specified by `m') * No operand required (specified by `--') All instructions are a single word, except for three double-word instructions. These three instructions were made double-word instructions so that all the required information is available in these 32 bits. In the second word, the 4 MSbs are `1's. If this second word is executed as an instruction (by itself), it will execute as a NOP. All single word instructions are executed in a single instruction cycle, unless a conditional test is true, or the program counter is changed as a result of the instruction. In these cases, the execution takes two instruction cycles, with the additional instruction cycle(s) executed as a NOP. The double-word instructions execute in two instruction cycles. One instruction cycle consists of four oscillator periods. Thus, for an oscillator frequency of 4 MHz, the normal instruction execution time is 1 s. If a conditional test is true, or the program counter is changed as a result of an instruction, the instruction execution time is 2 s. Two-word branch instructions (if true) would take 3 s. Figure 24-1 shows the general formats that the instructions can have. All examples use the format `nnh' to represent a hexadecimal number, where `h' signifies a hexadecimal digit. The Instruction Set Summary, shown in Table 24-2, lists the instructions recognized by the Microchip Assembler (MPASMTM). Section 24.1 provides a description of each instruction.
The PIC18 instruction set summary in Table 24-2 lists byte-oriented, bit-oriented, literal and control operations. Table 24-1 shows the opcode field descriptions. Most byte-oriented instructions have three operands: 1. 2. 3. The file register (specified by `f') The destination of the result (specified by `d') The accessed memory (specified by `a')
The file register designator 'f' specifies which file register is to be used by the instruction. The destination designator `d' specifies where the result of the operation is to be placed. If 'd' is zero, the result is placed in the WREG register. If 'd' is one, the result is placed in the file register specified in the instruction. All bit-oriented instructions have three operands: 1. 2. 3. The file register (specified by `f') The bit in the file register (specified by `b') The accessed memory (specified by `a')
The bit field designator 'b' selects the number of the bit affected by the operation, while the file register designator 'f' represents the number of the file in which the bit is located.
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PIC18FXX20
TABLE 24-1:
Field a
OPCODE FIELD DESCRIPTIONS
Description RAM access bit a = 0: RAM location in Access RAM (BSR register is ignored) a = 1: RAM bank is specified by BSR register Bit address within an 8-bit file register (0 to 7) Bank Select Register. Used to select the current RAM bank. Destination select bit d = 0: store result in WREG d = 1: store result in file register f. Destination either the WREG register or the specified register file location 8-bit Register file address (0x00 to 0xFF) 12-bit Register file address (0x000 to 0xFFF). This is the source address. 12-bit Register file address (0x000 to 0xFFF). This is the destination address. Literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value) Label name The mode of the TBLPTR register for the Table Read and Table Write instructions. Only used with Table Read and Table Write instructions: No Change to register (such as TBLPTR with Table Reads and Writes) Post-Increment register (such as TBLPTR with Table Reads and Writes) Post-Decrement register (such as TBLPTR with Table Reads and Writes) Pre-Increment register (such as TBLPTR with Table Reads and Writes) The relative address (2's complement number) for relative branch instructions, or the direct address for Call/Branch and Return instructions Product of Multiply high byte Product of Multiply low byte Fast Call/Return mode select bit s = 0: do not update into/from shadow registers s = 1: certain registers loaded into/from shadow registers (Fast mode) Unused or Unchanged Working register (accumulator) Don't care (0 or 1) The assembler will generate code with x = 0. It is the recommended form of use for compatibility with all Microchip software tools. 21-bit Table Pointer (points to a Program Memory location) 8-bit Table Latch Top-of-Stack Program Counter Program Counter Low Byte Program Counter High Byte Program Counter High Byte Latch Program Counter Upper Byte Latch Global Interrupt Enable bit Watchdog Timer Time-out bit Power-down bit ALU status bits Carry, Digit Carry, Zero, Overflow, Negative Optional Contents Assigned to Register bit field In the set of User defined term (font is courier)
bbb BSR d
dest f fs fd k label mm * *+ *+* n PRODH PRODL s
u WREG x
TBLPTR TABLAT TOS PC PCL PCH PCLATH PCLATU GIE WDT TO PD C, DC, Z, OV, N [ ( <> italics ] )
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PIC18FXX20
FIGURE 24-1: GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations 15 10 9 87 OPCODE d a 0 f (FILE #) ADDWF MYREG, W, B Example Instruction
d = 0 for result destination to be WREG register d = 1 for result destination to be file register (f) a = 0 to force Access Bank a = 1 for BSR to select bank f = 8-bit file register address Byte to Byte move operations (2-word) 15 12 11 OPCODE 15 12 11 1111 f (Destination FILE #) 0 f (Source FILE #) 0 MOVFF MYREG1, MYREG2
f = 12-bit file register address Bit-oriented file register operations 15 12 11 98 7 f (FILE #) 0 BSF MYREG, bit, B OPCODE b (BIT #) a
b = 3-bit position of bit in file register (f) a = 0 to force Access Bank a = 1 for BSR to select bank f = 8-bit file register address Literal operations 15 OPCODE k = 8-bit immediate value Control operations CALL, GOTO and Branch operations 15 OPCODE 15 1111 12 11 n<19:8> (literal) 87 n<7:0> (literal) 0 0 GOTO Label 8 7 k (literal) 0 MOVLW 0x7F
n = 20-bit immediate value 15 OPCODE 15 12 11 n<19:8> (literal) S = Fast bit 15 OPCODE 15 OPCODE 11 10 n<10:0> (literal) 87 n<7:0> (literal) 0 BC MYFUNC 0 BRA MYFUNC 87 S n<7:0> (literal) 0 0 CALL MYFUNC
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TABLE 24-2:
Mnemonic, Operands
PIC18FXXX INSTRUCTION SET
Description Cycles 16-Bit Instruction Word MSb 0010 01da0 0010 0da 0001 01da 0110 101a 0001 11da 0110 001a 0110 010a 0110 000a 0000 01da 0010 11da 0100 11da 0010 10da 0011 11da 0100 10da 0001 00da 0101 00da 1100 ffff 1111 ffff 0110 111a 0000 001a 0110 110a 0011 01da 0100 01da 0011 00da 0100 00da 0110 100a 0101 01da 0101 0101 0011 0110 0001 1001 1000 1011 1010 0111 11da 10da 10da 011a 10da bbba bbba bbba bbba bbba ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff LSb ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff Status Affected Notes
BYTE-ORIENTED FILE REGISTER OPERATIONS ADDWF ADDWFC ANDWF CLRF COMF CPFSEQ CPFSGT CPFSLT DECF DECFSZ DCFSNZ INCF INCFSZ INFSNZ IORWF MOVF MOVFF MOVWF MULWF NEGF RLCF RLNCF RRCF RRNCF SETF SUBFWB SUBWF SUBWFB SWAPF TSTFSZ XORWF BCF BSF BTFSC BTFSS BTG f, d, a f, d, a f, d, a f, a f, d, a f, a f, a f, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a fs, fd f, a f, a f, a f, d, a f, d, a f, d, a f, d, a f, a f, d, a f, d, a f, d, a f, d, a f, a f, d, a f, b, a f, b, a f, b, a f, b, a f, d, a Add WREG and f Add WREG and Carry bit to f AND WREG with f Clear f Complement f Compare f with WREG, skip = Compare f with WREG, skip > Compare f with WREG, skip < Decrement f Decrement f, Skip if 0 Decrement f, Skip if Not 0 Increment f Increment f, Skip if 0 Increment f, Skip if Not 0 Inclusive OR WREG with f Move f Move fs (source) to 1st word fd (destination)2nd word Move WREG to f Multiply WREG with f Negate f Rotate Left f through Carry Rotate Left f (No Carry) Rotate Right f through Carry Rotate Right f (No Carry) Set f Subtract f from WREG with borrow Subtract WREG from f Subtract WREG from f with borrow Swap nibbles in f Test f, skip if 0 Exclusive OR WREG with f Bit Clear f Bit Set f Bit Test f, Skip if Clear Bit Test f, Skip if Set Bit Toggle f 1 1 1 1 1 1 (2 or 3) 1 (2 or 3) 1 (2 or 3) 1 1 (2 or 3) 1 (2 or 3) 1 1 (2 or 3) 1 (2 or 3) 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 (2 or 3) 1 1 1 1 (2 or 3) 1 (2 or 3) 1 C, DC, Z, OV, N C, DC, Z, OV, N Z, N Z Z, N None None None C, DC, Z, OV, N None None C, DC, Z, OV, N None None Z, N Z, N None 1, 2 1, 2 1,2 2 1, 2 4 4 1, 2 1, 2, 3, 4 1, 2, 3, 4 1, 2 1, 2, 3, 4 4 1, 2 1, 2 1
None None C, DC, Z, OV, N 1, 2 C, Z, N Z, N 1, 2 C, Z, N Z, N None C, DC, Z, OV, N 1, 2
ffff C, DC, Z, OV, N ffff C, DC, Z, OV, N 1, 2 ffff None ffff None ffff Z, N ffff ffff ffff ffff ffff None None None None None 4 1, 2
BIT-ORIENTED FILE REGISTER OPERATIONS 1, 2 1, 2 3, 4 3, 4 1, 2
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value present on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an external device, the data will be written back with a '0'. 2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned. 3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP. 4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP, unless the first word of the instruction retrieves the information embedded in these 16-bits. This ensures that all program memory locations have a valid instruction. 5: If the Table Write starts the write cycle to internal memory, the write will continue until terminated.
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PIC18FXX20
TABLE 24-2:
Mnemonic, Operands CONTROL OPERATIONS BC BN BNC BNN BNOV BNZ BOV BRA BZ CALL CLRWDT DAW GOTO NOP NOP POP PUSH RCALL RESET RETFIE RETLW RETURN SLEEP n n n n n n n n n n, s -- -- n -- -- -- -- n s k s -- Branch if Carry Branch if Negative Branch if Not Carry Branch if Not Negative Branch if Not Overflow Branch if Not Zero Branch if Overflow Branch Unconditionally Branch if Zero Call subroutine1st word 2nd word Clear Watchdog Timer Decimal Adjust WREG Go to address 1st word 2nd word No Operation No Operation Pop top of return stack (TOS) Push top of return stack (TOS) Relative Call Software device RESET Return from interrupt enable Return with literal in WREG Return from Subroutine Go into Standby mode 1 (2) 1 (2) 1 (2) 1 (2) 1 (2) 2 1 (2) 1 (2) 1 (2) 2 1 1 2 1 1 1 1 2 1 2 2 2 1 1110 1110 1110 1110 1110 1110 1110 1101 1110 1110 1111 0000 0000 1110 1111 0000 1111 0000 0000 1101 0000 0000 0000 0000 0000 0010 0110 0011 0111 0101 0001 0100 0nnn 0000 110s kkkk 0000 0000 1111 kkkk 0000 xxxx 0000 0000 1nnn 0000 0000 1100 0000 0000 nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn kkkk kkkk 0000 0000 kkkk kkkk 0000 xxxx 0000 0000 nnnn 1111 0001 kkkk 0001 0000 nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn kkkk kkkk 0100 0111 kkkk kkkk 0000 xxxx 0110 0101 nnnn 1111 000s None None None None None None None None None None TO, PD C None
PIC18FXXX INSTRUCTION SET (CONTINUED)
Description Cycles 16-Bit Instruction Word MSb LSb Status Affected Notes
None None None None None All GIE/GIEH, PEIE/GIEL kkkk None 001s None 0011 TO, PD
4
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value present on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an external device, the data will be written back with a '0'. 2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned. 3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP. 4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP, unless the first word of the instruction retrieves the information embedded in these 16-bits. This ensures that all program memory locations have a valid instruction. 5: If the Table Write starts the write cycle to internal memory, the write will continue until terminated.
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PIC18FXX20
TABLE 24-2:
Mnemonic, Operands LITERAL OPERATIONS ADDLW ANDLW IORLW LFSR MOVLB MOVLW MULLW RETLW SUBLW XORLW TBLRD* TBLRD*+ TBLRD*TBLRD+* TBLWT* TBLWT*+ TBLWT*TBLWT+* k k k f, k k k k k k k Add literal and WREG AND literal with WREG Inclusive OR literal with WREG Move literal (12-bit) 2nd word to FSRx 1st word Move literal to BSR<3:0> Move literal to WREG Multiply literal with WREG Return with literal in WREG Subtract WREG from literal Exclusive OR literal with WREG Table Read Table Read with post-increment Table Read with post-decrement Table Read with pre-increment Table Write Table Write with post-increment Table Write with post-decrement Table Write with pre-increment 1 1 1 2 1 1 1 2 1 1 2 0000 0000 0000 1110 1111 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 1111 1011 1001 1110 0000 0001 1110 1101 1100 1000 1010 0000 0000 0000 0000 0000 0000 0000 0000 kkkk kkkk kkkk 00ff kkkk 0000 kkkk kkkk kkkk kkkk kkkk 0000 0000 0000 0000 0000 0000 0000 0000 kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk 1000 1001 1010 1011 1100 1101 1110 1111 C, DC, Z, OV, N Z, N Z, N None None None None None C, DC, Z, OV, N Z, N None None None None None None None None
PIC18FXXX INSTRUCTION SET (CONTINUED)
Description Cycles 16-Bit Instruction Word MSb LSb Status Affected Notes
DATA MEMORY PROGRAM MEMORY OPERATIONS
2 (5)
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value present on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an external device, the data will be written back with a '0'. 2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned. 3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP. 4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP, unless the first word of the instruction retrieves the information embedded in these 16-bits. This ensures that all program memory locations have a valid instruction. 5: If the Table Write starts the write cycle to internal memory, the write will continue until terminated.
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PIC18FXX20
24.1
ADDLW Syntax: Operands: Operation: Status Affected: Encoding: Description:
Instruction Set
ADD literal to W [ label ] ADDLW 0 k 255 (W) + k W N, OV, C, DC, Z
0000 1111 kkkk kkkk
ADDWF k Syntax: Operands:
ADD W to f [ label ] ADDWF 0 f 255 d [0,1] a [0,1] (W) + (f) dest N, OV, C, DC, Z
0010 01da ffff ffff
f [,d [,a] f [,d [,a]
Operation: Status Affected: Encoding: Description:
The contents of W are added to the 8-bit literal 'k' and the result is placed in W. 1 1 Q2
Read literal 'k' ADDLW
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data 0x15
Q4
Write to W
Add W to register 'f'. If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected. If `a' is 1, the BSR is used. 1 1 Q2
Read register 'f' ADDWF
Words: Cycles: Q Cycle Activity: Q1
Decode
Example:
W W = =
Before Instruction
0x10 0x25
Q3
Process Data REG, 0, 0
Q4
Write to destination
After Instruction Example:
W REG W REG = = = =
Before Instruction
0x17 0xC2 0xD9 0xC2
After Instruction
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PIC18FXX20
ADDWFC Syntax: Operands: ADD W and Carry bit to f [ label ] ADDWFC 0 f 255 d [0,1] a [0,1] (W) + (f) + (C) dest N,OV, C, DC, Z
0010 00da ffff ffff
ANDLW Syntax: Operands: Operation: Status Affected: Encoding: Description:
AND literal with W [ label ] ANDLW 0 k 255 (W) .AND. k W N,Z
0000 1011 kkkk kkkk
f [,d [,a]
k
Operation: Status Affected: Encoding: Description:
Add W, the Carry Flag and data memory location 'f'. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed in data memory location 'f'. If `a' is 0, the Access Bank will be selected. If `a' is 1, the BSR will not be overridden. 1 1
The contents of W are ANDed with the 8-bit literal 'k'. The result is placed in W. 1 1 Q2
Read literal 'k' ANDLW
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data 0x5F
Q4
Write to W
Words: Cycles: Q Cycle Activity: Q1
Decode
Example: Q2
Read register 'f' ADDWFC 1 0x02 0x4D 0 0x02 0x50
Q3
Process Data REG, 0, 1
Q4
Write to destination
Before Instruction
W W = = 0xA3 0x03
After Instruction
Example:
Carry bit = REG = W =
Before Instruction
After Instruction
Carry bit = REG = W =
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PIC18FXX20
ANDWF Syntax: Operands: AND W with f [ label ] ANDWF 0 f 255 d [0,1] a [0,1] (W) .AND. (f) dest N,Z
0001 01da ffff ffff
BC f [,d [,a] Syntax: Operands: Operation: Status Affected: Encoding: Description:
Branch if Carry [ label ] BC n -128 n 127 if carry bit is '1' (PC) + 2 + 2n PC None
1110 0010 nnnn nnnn
Operation: Status Affected: Encoding: Description:
The contents of W are AND'ed with register 'f'. If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected. If `a' is 1, the BSR will not be overridden (default). 1 1 Q2
Read register 'f' ANDWF
If the Carry bit is `1', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
Words: Cycles: Q Cycle Activity: Q1
Decode
Words: Cycles: Q3
Process Data REG, 0, 0
Q4
Write to destination
Q Cycle Activity: If Jump: Q1
Decode No operation
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
Example:
W REG W REG = = = =
Before Instruction
0x17 0xC2 0x02 0xC2
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BC 5
Q4
No operation
After Instruction
Example:
PC
Before Instruction
address (HERE) 1; address (HERE+12) 0; address (HERE+2)
After Instruction
If Carry PC If Carry PC
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PIC18FXX20
BCF Syntax: Operands: Bit Clear f [ label ] BCF 0 f 255 0b7 a [0,1] 0 f None
1001 bbba ffff ffff
BN f,b[,a] Syntax: Operands: Operation: Status Affected: Encoding: Description:
Branch if Negative [ label ] BN n -128 n 127 if negative bit is '1' (PC) + 2 + 2n PC None
1110 0110 nnnn nnnn
Operation: Status Affected: Encoding: Description:
Bit 'b' in register 'f' is cleared. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' BCF
Words: Cycles: Q Cycle Activity: Q1
Decode
If the Negative bit is `1', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
Words: Cycles: Q3
Process Data FLAG_REG,
Q4
Write register 'f' 7, 0
Q Cycle Activity: If Jump: Q1
Decode
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
Example:
Before Instruction
FLAG_REG = 0xC7
No operation
After Instruction
FLAG_REG = 0x47
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BN Jump
Q4
No operation
Example:
PC
Before Instruction
address (HERE) 1; address (Jump) 0; address (HERE+2)
After Instruction
If Negative PC If Negative PC
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PIC18FXX20
BNC Syntax: Operands: Operation: Status Affected: Encoding: Description: Branch if Not Carry [ label ] BNC -128 n 127 if carry bit is '0' (PC) + 2 + 2n PC None
1110 0011 nnnn nnnn
BNN Syntax: Operands: Operation: Status Affected: Encoding: Description:
Branch if Not Negative [ label ] BNN -128 n 127 if negative bit is '0' (PC) + 2 + 2n PC None
1110 0111 nnnn nnnn
n
n
If the Carry bit is `0', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
If the Negative bit is `0', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
Words: Cycles: Q Cycle Activity: If Jump: Q1
Decode No operation
Words: Cycles: Q Cycle Activity: If Jump: Q1
Decode No operation
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BNC Jump
Q4
No operation
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BNN Jump
Q4
No operation
Example:
PC
Example:
PC
Before Instruction
address (HERE) 0; address (Jump) 1; address (HERE+2)
Before Instruction
address (HERE) 0; address (Jump) 1; address (HERE+2)
After Instruction
If Carry PC If Carry PC
After Instruction
If Negative PC If Negative PC
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PIC18FXX20
BNOV Syntax: Operands: Operation: Status Affected: Encoding: Description: Branch if Not Overflow [ label ] BNOV -128 n 127 if overflow bit is '0' (PC) + 2 + 2n PC None
1110 0101 nnnn nnnn
BNZ Syntax: Operands: Operation: Status Affected: Encoding: Description:
Branch if Not Zero [ label ] BNZ -128 n 127 if zero bit is '0' (PC) + 2 + 2n PC None
1110 0001 nnnn nnnn
n
n
If the Overflow bit is `0', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
If the Zero bit is `0', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
Words: Cycles: Q Cycle Activity: If Jump: Q1
Decode No operation
Words: Cycles: Q Cycle Activity: If Jump: Q1
Decode No operation
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BNOV Jump address (HERE) 0; address (Jump) 1; address (HERE+2)
Q4
No operation
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BNZ Jump
Q4
No operation
Example:
PC
Example:
PC
Before Instruction After Instruction
If Overflow PC If Overflow PC
Before Instruction
address (HERE) 0; address (Jump) 1; address (HERE+2)
After Instruction
If Zero PC If Zero PC
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PIC18FXX20
BRA Syntax: Operands: Operation: Status Affected: Encoding: Description: Unconditional Branch [ label ] BRA n -1024 n 1023 (PC) + 2 + 2n PC None
1101 0nnn nnnn nnnn
BSF Syntax: Operands:
Bit Set f [ label ] BSF 0 f 255 0b7 a [0,1] 1 f None
1000 bbba ffff ffff
f,b[,a]
Operation: Status Affected: Encoding: Description:
Add the 2's complement number `2n' to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is a two-cycle instruction. 1 2 Q2
Read literal 'n' No operation
Words: Cycles: Q Cycle Activity: Q1
Decode No operation
Bit 'b' in register 'f' is set. If `a' is 0 Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value. 1 1 Q2
Read register 'f' BSF = =
Words: Cycles: Q3
Process Data No operation
Q4
Write to PC No operation
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write register 'f'
Example: Example:
PC HERE = = BRA Jump
FLAG_REG, 7, 1 0x0A 0x8A
Before Instruction
FLAG_REG
Before Instruction
address (HERE) address (Jump)
After Instruction
FLAG_REG
After Instruction
PC
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 271
PIC18FXX20
BTFSC Syntax: Operands: Bit Test File, Skip if Clear [ label ] BTFSC f,b[,a] 0 f 255 0b7 a [0,1] skip if (f) = 0 None
1011 bbba ffff ffff
BTFSS Syntax: Operands:
Bit Test File, Skip if Set [ label ] BTFSS f,b[,a] 0 f 255 0b<7 a [0,1] skip if (f) = 1 None
1010 bbba ffff ffff
Operation: Status Affected: Encoding: Description:
Operation: Status Affected: Encoding: Description:
If bit 'b' in register `f' is 0, then the next instruction is skipped. If bit 'b' is 0, then the next instruction fetched during the current instruction execution is discarded, and a NOP is executed instead, making this a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
If bit 'b' in register 'f' is 1, then the next instruction is skipped. If bit 'b' is 1, then the next instruction fetched during the current instruction execution, is discarded and a NOP is executed instead, making this a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q3
Process Data
Words: Cycles:
Words: Cycles:
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
No operation
Q Cycle Activity: Q1
Decode
Q2
Read register 'f'
Q4
No operation
If skip: Q1
No operation
If skip: Q2
No operation
Q3
No operation
Q4
No operation
Q1
No operation
Q2
No operation
Q3
No operation
Q4
No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE FALSE TRUE = = = = = No operation No operation BTFSC : :
Q4
No operation No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE FALSE TRUE = = = = = No operation No operation BTFSS : :
Q4
No operation No operation
Example:
FLAG, 1, 0
Example:
FLAG, 1, 0
Before Instruction
PC address (HERE) 0; address (TRUE) 1; address (FALSE)
Before Instruction
PC address (HERE) 0; address (FALSE) 1; address (TRUE)
After Instruction
If FLAG<1> PC If FLAG<1> PC
After Instruction
If FLAG<1> PC If FLAG<1> PC
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PIC18FXX20
BTG Syntax: Operands: Bit Toggle f [ label ] BTG f,b[,a] 0 f 255 0b<7 a [0,1] (f) f None
0111 bbba ffff ffff
BOV Syntax: Operands: Operation: Status Affected: Encoding: Description:
Branch if Overflow [ label ] BOV -128 n 127 if overflow bit is '1' (PC) + 2 + 2n PC None
1110 0100 nnnn nnnn
n
Operation: Status Affected: Encoding: Description:
Bit 'b' in data memory location 'f' is inverted. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' BTG = =
Words: Cycles: Q Cycle Activity: Q1
Decode
If the Overflow bit is `1', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
Words: Cycles: Q3
Process Data PORTC, 4, 0 No operation
Q4
Write register 'f'
Q Cycle Activity: If Jump: Q1
Decode
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
Example:
PORTC PORTC
Before Instruction:
0111 0101 [0x75] 0110 0101 [0x65]
After Instruction:
If No Jump: Q1
Decode
Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BOV Jump
Q4
No operation
Example:
PC
Before Instruction
address (HERE) 1; address (Jump) 0; address (HERE+2)
After Instruction
If Overflow PC If Overflow PC
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 273
PIC18FXX20
BZ Syntax: Operands: Operation: Status Affected: Encoding: Description: Branch if Zero [ label ] BZ n -128 n 127 if Zero bit is '1' (PC) + 2 + 2n PC None
1110 0000 nnnn nnnn
CALL Syntax: Operands: Operation:
Subroutine Call [ label ] CALL k [,s] 0 k 1048575 s [0,1] (PC) + 4 TOS, k PC<20:1>, if s = 1 (W) WS, (STATUS) STATUSS, (BSR) BSRS None
1110 1111 110s k19kkk k7kkk kkkk kkkk0 kkkk8
If the Zero bit is `1', then the program will branch. The 2's complement number `2n' is added to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is then a two-cycle instruction. 1 1(2)
Status Affected: Encoding: 1st word (k<7:0>) 2nd word(k<19:8>) Description:
Words: Cycles: Q Cycle Activity: If Jump: Q1
Decode No operation
Q2
Read literal 'n' No operation
Q3
Process Data No operation
Q4
Write to PC No operation
Subroutine call of entire 2-Mbyte memory range. First, return address (PC+ 4) is pushed onto the return stack. If `s' = 1, the W, STATUS and BSR registers are also pushed into their respective shadow registers, WS, STATUSS and BSRS. If 's' = 0, no update occurs (default). Then, the 20-bit value `k' is loaded into PC<20:1>. CALL is a two-cycle instruction. 2 2 Q2
Read literal 'k'<7:0>, No operation HERE =
If No Jump: Q1
Decode
Words: Q2
Read literal 'n' HERE = = = = =
Q3
Process Data BZ Jump
Q4
No operation
Cycles: Q Cycle Activity: Q1
Decode
Q3
Push PC to stack No operation CALL
Q4
Read literal 'k'<19:8>, Write to PC No operation
Example:
PC
Before Instruction
address (HERE) 1; address (Jump) 0; address (HERE+2)
After Instruction
If Zero PC If Zero PC
No operation
Example:
PC
THERE,1
Before Instruction
address (HERE) address (THERE) address (HERE + 4) W BSR STATUS
After Instruction
PC = TOS = WS = BSRS = STATUSS=
DS39609A-page 274
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2003 Microchip Technology Inc.
PIC18FXX20
CLRF Syntax: Operands: Operation: Status Affected: Encoding: Description: Clear f [label] CLRF 0 f 255 a [0,1] 000h f 1Z Z
0110 101a ffff ffff
CLRWDT f [,a] Syntax: Operands: Operation:
Clear Watchdog Timer [ label ] CLRWDT None 000h WDT, 000h WDT postscaler, 1 TO, 1 PD TO, PD
0000 0000 0000 0100
Status Affected: Encoding: Description:
Clears the contents of the specified register. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' CLRF = =
CLRWDT instruction resets the Watchdog Timer. It also resets the postscaler of the WDT. Status bits TO and PD are set. 1 1 Q2
No operation CLRWDT = = = = = ? 0x00 0 1 1
Words: Cycles: Q Cycle Activity: Q1
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
No operation
Q3
Process Data FLAG_REG,1 0x5A 0x00
Q4
Write register 'f'
Decode
Example: Example: Before Instruction
FLAG_REG
Before Instruction
WDT Counter
After Instruction
WDT Counter WDT Postscaler
After Instruction
FLAG_REG
TO PD
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 275
PIC18FXX20
COMF Syntax: Operands: Complement f [ label ] COMF 0 f 255 d [0,1] a [0,1] ( f ) dest N, Z
0001 11da ffff ffff
CPFSEQ f [,d [,a] Syntax: Operands: Operation:
Compare f with W, skip if f = W [ label ] CPFSEQ 0 f 255 a [0,1] (f) - (W), skip if (f) = (W) (unsigned comparison) None
0110 001a ffff ffff
f [,a]
Operation: Status Affected: Encoding: Description:
Status Affected: Encoding: Description:
The contents of register 'f' are complemented. If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' COMF = = = 0x13 0x13 0xEC
Words: Cycles: Q Cycle Activity: Q1
Decode
Compares the contents of data memory location 'f' to the contents of W by performing an unsigned subtraction. If 'f' = W, then the fetched instruction is discarded and a NOP is executed instead, making this a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
Q3
Process Data REG, 0, 0
Q4
Write to destination
Words: Cycles:
Example:
REG REG W
Before Instruction After Instruction
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
No operation
If skip: Q1
No operation
Q2
No operation
Q3
No operation
Q4
No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE NEQUAL EQUAL = = = = = = No operation No operation
Q4
No operation No operation
Example:
CPFSEQ REG, 0 : : HERE ? ? W; Address (EQUAL) W; Address (NEQUAL)
Before Instruction
PC Address W REG
After Instruction
If REG PC If REG PC
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PIC18FXX20
CPFSGT Syntax: Operands: Operation: Compare f with W, skip if f > W [ label ] CPFSGT 0 f 255 a [0,1] (f) - (W), skip if (f) > (W) (unsigned comparison) None
0110 010a ffff ffff
CPFSLT Syntax: Operands: Operation:
Compare f with W, skip if f < W [ label ] CPFSLT 0 f 255 a [0,1] (f) - (W), skip if (f) < (W) (unsigned comparison) None
0110 000a ffff ffff
f [,a]
f [,a]
Status Affected: Encoding: Description:
Status Affected: Encoding: Description:
Compares the contents of data memory location 'f' to the contents of the W by performing an unsigned subtraction. If the contents of 'f' are greater than the contents of WREG, then the fetched instruction is discarded and a NOP is executed instead, making this a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
Compares the contents of data memory location 'f' to the contents of W by performing an unsigned subtraction. If the contents of 'f' are less than the contents of W, then the fetched instruction is discarded and a NOP is executed instead, making this a two-cycle instruction. If `a' is 0, the Access Bank will be selected. If `a' is 1, the BSR will not be overridden (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
Words: Cycles:
Words: Cycles:
Q Cycle Activity: Q1
Decode
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
No operation
Q3
Process Data
Q4
No operation
If skip: Q1
No operation
If skip: Q1
No operation
Q2
No operation
Q3
No operation
Q4
No operation
Q2
No operation
Q3
No operation
Q4
No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE NGREATER GREATER = = > = = No operation No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE NLESS LESS = = < = = No operation No operation
Q4
No operation No operation
Q4
No operation No operation
Example:
Example:
CPFSGT REG, 0 : :
CPFSLT REG, 1 : : Address (HERE) ? W; Address (LESS) W; Address (NLESS)
Before Instruction
PC W
Before Instruction
PC W Address (HERE) ? W; Address (GREATER) W; Address (NGREATER)
After Instruction
If REG PC If REG PC
After Instruction
If REG PC If REG PC
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Advance Information
DS39609A-page 277
PIC18FXX20
DAW Syntax: Operands: Operation: Decimal Adjust W Register [label] DAW None If [W<3:0> >9] or [DC = 1] then (W<3:0>) + 6 W<3:0>; else (W<3:0>) W<3:0>; If [W<7:4> >9] or [C = 1] then (W<7:4>) + 6 W<7:4>; else (W<7:4>) W<7:4>; Status Affected: Encoding: Description: C
0000 0000 0000 0111
DECF Syntax: Operands:
Decrement f [ label ] DECF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) - 1 dest C, DC, N, OV, Z
0000 01da ffff ffff
Operation: Status Affected: Encoding: Description:
DAW adjusts the eight-bit value in W, resulting from the earlier addition of two variables (each in packed BCD format) and produces a correct packed BCD result. 1 1 Q2
Read register W DAW
Decrement register 'f'. If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' DECF = = = = 0x01 0 0x00 1
Words: Cycles: Q Cycle Activity: Q1
Decode
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data CNT, 1, 0
Q4
Write to destination
Q3
Process Data
Q4
Write W
Example:
CNT Z CNT Z
Before Instruction After Instruction
Example1:
W C DC W C DC = = = = = =
Before Instruction
0xA5 0 0 0x05 1 0
After Instruction
Example 2:
Before Instruction
W C DC W C DC = = = = = = 0xCE 0 0 0x34 1 0
After Instruction
DS39609A-page 278
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PIC18FXX20
DECFSZ Syntax: Operands: Decrement f, skip if 0 [ label ] DECFSZ f [,d [,a]] 0 f 255 d [0,1] a [0,1] (f) - 1 dest, skip if result = 0 None
0010 11da ffff ffff
DCFSNZ Syntax: Operands:
Decrement f, skip if not 0 [label] DCFSNZ 0 f 255 d [0,1] a [0,1] (f) - 1 dest, skip if result 0 None
0100 11da ffff ffff
f [,d [,a]
Operation: Status Affected: Encoding: Description:
Operation: Status Affected: Encoding: Description:
The contents of register 'f' are decremented. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If the result is 0, the next instruction, which is already fetched, is discarded and a NOP is executed instead, making it a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
The contents of register 'f' are decremented. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If the result is not 0, the next instruction, which is already fetched, is discarded, and a NOP is executed instead, making it a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
Words: Cycles:
Words: Cycles:
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write to destination
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write to destination
If skip: Q1
No operation
If skip: Q2
No operation
Q3
No operation
Q4
No operation
Q1
No operation
Q2
No operation
Q3
No operation
Q4
No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE CONTINUE No operation No operation DECFSZ GOTO
Q4
No operation No operation CNT, 1, 1 LOOP
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE ZERO NZERO = = = = = No operation No operation DCFSNZ : : ?
Q4
No operation No operation
Example:
Example:
TEMP, 1, 0
Before Instruction
PC CNT If CNT PC If CNT PC = = = = = Address (HERE) CNT - 1 0; Address (CONTINUE) 0; Address (HERE+2)
Before Instruction
TEMP
After Instruction
After Instruction
TEMP If TEMP PC If TEMP PC TEMP - 1, 0; Address (ZERO) 0; Address (NZERO)
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Advance Information
DS39609A-page 279
PIC18FXX20
GOTO Syntax: Operands: Operation: Status Affected: Encoding: 1st word (k<7:0>) 2nd word(k<19:8>) Description: Unconditional Branch [ label ] GOTO k 0 k 1048575 k PC<20:1> None
1110 1111 1111 k19kkk k7kkk kkkk kkkk0 kkkk8
INCF Syntax: Operands:
Increment f [ label ] INCF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) + 1 dest C, DC, N, OV, Z
0010 10da ffff ffff
Operation: Status Affected: Encoding: Description:
GOTO allows an unconditional branch anywhere within entire 2-Mbyte memory range. The 20-bit value `k' is loaded into PC<20:1>. GOTO is always a two-cycle instruction. 2 2 Q2
Read literal 'k'<7:0>, No operation
Words: Cycles: Q Cycle Activity: Q1
Decode
The contents of register 'f' are incremented. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' INCF = = = = = = = = 0xFF 0 ? ? 0x00 1 1 1
Q3
No operation No operation
Q4
Read literal 'k'<19:8>, Write to PC No operation
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data CNT, 1, 0
Q4
Write to destination
No operation
Example:
PC =
GOTO THERE Address (THERE)
Example:
CNT Z C DC CNT Z C DC
After Instruction
Before Instruction
After Instruction
DS39609A-page 280
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PIC18FXX20
INCFSZ Syntax: Operands: Increment f, skip if 0 [ label ] INCFSZ f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) + 1 dest, skip if result = 0 None
0011 11da ffff ffff
INFSNZ Syntax: Operands:
Increment f, skip if not 0 [label] INFSNZ f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) + 1 dest, skip if result 0 None
0100 10da ffff ffff
Operation: Status Affected: Encoding: Description:
Operation: Status Affected: Encoding: Description:
The contents of register 'f' are incremented. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f'. (default) If the result is 0, the next instruction, which is already fetched, is discarded, and a NOP is executed instead, making it a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
The contents of register 'f' are incremented. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If the result is not 0, the next instruction, which is already fetched, is discarded, and a NOP is executed instead, making it a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
Words: Cycles:
Words: Cycles:
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write to destination
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write to destination
If skip: Q1
No operation
If skip: Q2
No operation
Q3
No operation
Q4
No operation
Q1
No operation
Q2
No operation
Q3
No operation
Q4
No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE NZERO ZERO = = = = = No operation No operation INCFSZ : :
Q4
No operation No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE ZERO NZERO = = No operation No operation INFSNZ
Q4
No operation No operation
Example:
CNT, 1, 0
Example:
REG, 1, 0
Before Instruction
PC CNT If CNT PC If CNT PC Address (HERE) CNT + 1 0; Address (ZERO) 0; Address (NZERO)
Before Instruction
PC REG If REG PC If REG PC Address (HERE) REG + 1 0; Address (NZERO) 0; Address (ZERO)
After Instruction
After Instruction
= = =
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 281
PIC18FXX20
IORLW Syntax: Operands: Operation: Status Affected: Encoding: Description: Inclusive OR literal with W [ label ] IORLW k 0 k 255 (W) .OR. k W N, Z
0000 1001 kkkk kkkk
IORWF Syntax: Operands:
Inclusive OR W with f [ label ] IORWF f [,d [,a] 0 f 255 d [0,1] a [0,1] (W) .OR. (f) dest N, Z
0001 00da ffff ffff
Operation: Status Affected: Encoding: Description:
The contents of W are OR'ed with the eight-bit literal 'k'. The result is placed in W. 1 1 Q2
Read literal 'k' IORLW
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data 0x35
Q4
Write to W
Inclusive OR W with register 'f'. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' IORWF 0x13 0x91 0x13 0x93
Words: Example:
W W = =
Cycles: Q Cycle Activity: Q1
Decode
Before Instruction
0x9A 0xBF
Q3
Process Data RESULT, 0, 1
Q4
Write to destination
After Instruction
Example:
RESULT = W =
Before Instruction
After Instruction
RESULT = W =
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PIC18FXX20
LFSR Syntax: Operands: Operation: Status Affected: Encoding: Description: Load FSR [ label ] LFSR f,k 0f2 0 k 4095 k FSRf None
1110 1111 1110 0000 00ff k7kkk k11kkk kkkk
MOVF Syntax: Operands:
Move f [ label ] MOVF f [,d [,a] 0 f 255 d [0,1] a [0,1] f dest N, Z
0101 00da ffff ffff
Operation: Status Affected: Encoding: Description:
The 12-bit literal 'k' is loaded into the file select register pointed to by 'f'. 2 2 Q2
Read literal 'k' MSB
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write literal 'k' MSB to FSRfH Write literal 'k' to FSRfL
The contents of register 'f' are moved to a destination dependent upon the status of 'd'. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). Location 'f' can be anywhere in the 256-byte bank. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' MOVF = = = =
Decode
Read literal 'k' LSB
Process Data
Words: Cycles: Q Cycle Activity: Q1
Decode
Example:
FSR2H FSR2L
LFSR 2, 0x3AB = = 0x03 0xAB
After Instruction
Q3
Process Data REG, 0, 0 0x22 0xFF 0x22 0x22
Q4
Write W
Example:
REG W
Before Instruction
After Instruction
REG W
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Advance Information
DS39609A-page 283
PIC18FXX20
MOVFF Syntax: Operands: Operation: Status Affected: Encoding: 1st word (source) 2nd word (destin.) Description: Move f to f [label] MOVFF fs,fd 0 fs 4095 0 fd 4095 (fs) fd None
1100 1111 ffff ffff ffff ffff ffffs ffffd
MOVLB Syntax: Operands: Operation: Status Affected: Encoding: Description: Words: Cycles: Q Cycle Activity: Q1
Decode
Move literal to low nibble in BSR [ label ] k BSR None
0000 0001 kkkk kkkk
MOVLB k
0 k 255
The 8-bit literal 'k' is loaded into the Bank Select Register (BSR). 1 1 Q2
Read literal 'k'
The contents of source register 'fs' are moved to destination register 'fd'. Location of source 'fs' can be anywhere in the 4096-byte data space (000h to FFFh), and location of destination 'fd' can also be anywhere from 000h to FFFh. Either source or destination can be W (a useful special situation). MOVFF is particularly useful for transferring a data memory location to a peripheral register (such as the transmit buffer or an I/O port). The MOVFF instruction cannot use the PCL, TOSU, TOSH or TOSL as the destination register.
Q3
Process Data
Q4
Write literal 'k' to BSR
Example:
MOVLB = =
5 0x02 0x05
Before Instruction
BSR register
After Instruction
BSR register
Words: Cycles: Q Cycle Activity: Q1
Decode
2 2 (3) Q2
Read register 'f' (src) No operation No dummy read
Q3
Process Data No operation
Q4
No operation Write register 'f' (dest)
Decode
Example:
REG1 REG2
MOVFF = = = =
REG1, REG2 0x33 0x11 0x33, 0x33
Before Instruction After Instruction
REG1 REG2
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PIC18FXX20
MOVLW Syntax: Operands: Operation: Status Affected: Encoding: Description: Words: Cycles: Q Cycle Activity: Q1
Decode
Move literal to W [ label ] kW None
0000 1110 kkkk kkkk
MOVWF Syntax: Operands: Operation: Status Affected: Encoding: Description:
Move W to f [ label ] MOVWF f [,a] 0 f 255 a [0,1] (W) f None
0110 111a ffff ffff
MOVLW k
0 k 255
The eight-bit literal 'k' is loaded into W. 1 1 Q2
Read literal 'k' MOVLW
Q3
Process Data 0x5A
Q4
Write to W
Move data from W to register 'f'. Location 'f' can be anywhere in the 256-byte bank. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' MOVWF
Words: Cycles: Q Cycle Activity: Q1
Decode
Example:
W =
After Instruction
0x5A
Q3
Process Data REG, 0
Q4
Write register 'f'
Example:
W REG W REG = = = =
Before Instruction
0x4F 0xFF 0x4F 0x4F
After Instruction
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PIC18FXX20
MULLW Syntax: Operands: Operation: Status Affected: Encoding: Description: Multiply Literal with W [ label ] MULLW k 0 k 255 (W) x k PRODH:PRODL None
0000 1101 kkkk kkkk
MULWF Syntax: Operands: Operation: Status Affected: Encoding: Description:
Multiply W with f [ label ] MULWF f [,a] 0 f 255 a [0,1] (W) x (f) PRODH:PRODL None
0000 001a ffff ffff
An unsigned multiplication is carried out between the contents of W and the 8-bit literal 'k'. The 16-bit result is placed in PRODH:PRODL register pair. PRODH contains the high byte. W is unchanged. None of the status flags are affected. Note that neither overflow nor carry is possible in this operation. A zero result is possible but not detected. 1 1 Q2
Read literal 'k'
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write registers PRODH: PRODL
An unsigned multiplication is carried out between the contents of W and the register file location 'f'. The 16-bit result is stored in the PRODH:PRODL register pair. PRODH contains the high byte. Both W and 'f' are unchanged. None of the status flags are affected. Note that neither overflow nor carry is possible in this operation. A zero result is possible but not detected. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a'= 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f'
Words: Cycles: Q Cycle Activity: Q1
Decode
Example:
W PRODH PRODL
MULLW
0xC4
Q3
Process Data
Q4
Write registers PRODH: PRODL
Before Instruction
= = = = = = 0xE2 ? ? 0xE2 0xAD 0x08
After Instruction
W PRODH PRODL
Example:
W REG PRODH PRODL
MULWF
REG, 1
Before Instruction
= = = = = = = = 0xC4 0xB5 ? ? 0xC4 0xB5 0x8A 0x94
After Instruction
W REG PRODH PRODL
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PIC18FXX20
NEGF Syntax: Operands: Operation: Status Affected: Encoding: Description: Negate f [label] NEGF f [,a] 0 f 255 a [0,1] (f)+1f N, OV, C, DC, Z
0110 110a ffff ffff
NOP Syntax: Operands: Operation: Status Affected: Encoding: Description: Words: Cycles: Q Cycle Activity: Q1
Decode
No Operation [ label ] None No operation None
0000 1111 0000 xxxx 0000 xxxx 0000 xxxx
NOP
Location `f' is negated using two's complement. The result is placed in the data memory location 'f'. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value. 1 1 Q2
Read register 'f' NEGF = =
No operation. 1 1 Q2
No operation
Q3
No operation
Q4
No operation
Words: Cycles: Q Cycle Activity: Q1
Decode
Example: Q3
Process Data REG, 1
Q4
Write register 'f'
None.
Example:
REG REG
Before Instruction
0011 1010 [0x3A] 1100 0110 [0xC6]
After Instruction
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PIC18FXX20
POP Syntax: Operands: Operation: Status Affected: Encoding: Description: Pop Top of Return Stack [ label ] None (TOS) bit bucket None
0000 0000 0000 0110
PUSH Syntax: Operands: Operation: Status Affected: Encoding: Description:
Push Top of Return Stack [ label ] None (PC+2) TOS None
0000 0000 0000 0101
POP
PUSH
The TOS value is pulled off the return stack and is discarded. The TOS value then becomes the previous value that was pushed onto the return stack. This instruction is provided to enable the user to properly manage the return stack to incorporate a software stack. 1 1 Q2
No operation POP GOTO
The PC+2 is pushed onto the top of the return stack. The previous TOS value is pushed down on the stack. This instruction allows implementing a software stack by modifying TOS, and then pushing it onto the return stack. 1 1 Q2
PUSH PC+2 onto return stack PUSH = = 00345Ah 000124h
Words: Cycles: Q Cycle Activity: Q1
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
No operation
Q4
No operation
Q3
POP TOS value
Q4
No operation
Decode
Example: Example:
NEW = = 0031A2h 014332h TOS PC
Before Instruction
Before Instruction
TOS Stack (1 level down)
After Instruction
PC TOS Stack (1 level down) = = = 000126h 000126h 00345Ah
After Instruction
TOS PC = = 014332h NEW
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PIC18FXX20
RCALL Syntax: Operands: Operation: Status Affected: Encoding: Description: Relative Call [ label ] RCALL -1024 n 1023 (PC) + 2 TOS, (PC) + 2 + 2n PC None
1101 1nnn nnnn nnnn
RESET n Syntax: Operands: Operation: Status Affected: Encoding: Description: Words: Cycles: Q Cycle Activity: Q1
Decode
Reset [ label ] None Reset all registers and flags that are affected by a MCLR Reset. All
0000 0000 1111 1111
RESET
Subroutine call with a jump up to 1K from the current location. First, return address (PC+2) is pushed onto the stack. Then, add the 2's complement number `2n' to the PC. Since the PC will have incremented to fetch the next instruction, the new address will be PC+2+2n. This instruction is a two-cycle instruction. 1 2 Q2
Read literal 'n' Push PC to stack
This instruction provides a way to execute a MCLR Reset in software. 1 1 Q2
Start reset RESET Reset Value Reset Value
Q3
No operation
Q4
No operation
Words: Cycles: Q Cycle Activity: Q1
Decode
Example:
Registers = Flags* =
After Instruction Q3
Process Data
Q4
Write to PC
No operation
No operation HERE
No operation RCALL Jump
No operation
Example:
PC = PC = TOS =
Before Instruction
Address (HERE) Address (Jump) Address (HERE+2)
After Instruction
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PIC18FXX20
RETFIE Syntax: Operands: Operation: Return from Interrupt [ label ] s [0,1] (TOS) PC, 1 GIE/GIEH or PEIE/GIEL, if s = 1 (WS) W, (STATUSS) STATUS, (BSRS) BSR, PCLATU, PCLATH are unchanged. GIE/GIEH, PEIE/GIEL.
0000 0000 0001 000s
RETLW Syntax: Operands: Operation:
Return Literal to W [ label ] RETLW k 0 k 255 k W, (TOS) PC, PCLATU, PCLATH are unchanged None
0000 1100 kkkk kkkk
RETFIE [s]
Status Affected: Encoding: Description:
Status Affected: Encoding: Description:
Return from Interrupt. Stack is popped and Top-of-Stack (TOS) is loaded into the PC. Interrupts are enabled by setting either the high or low priority global interrupt enable bit. If `s' = 1, the contents of the shadow registers WS, STATUSS and BSRS are loaded into their corresponding registers, W, STATUS and BSR. If `s' = 0, no update of these registers occurs (default). 1 2 Q2
No operation
W is loaded with the eight-bit literal 'k'. The program counter is loaded from the top of the stack (the return address). The high address latch (PCLATH) remains unchanged. 1 2 Q2
Read literal 'k' No operation
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data No operation
Q4
pop PC from stack, Write to W No operation
No operation
Words: Cycles: Q Cycle Activity: Q1
Decode
Example:
CALL TABLE ; ; ; ; : TABLE ADDWF PCL ; RETLW k0 ; RETLW k1 ; : : RETLW kn ; W contains table offset value W now has table value
Q3
No operation
Q4
pop PC from stack Set GIEH or GIEL
No operation
No operation RETFIE 1
No operation
No operation
W = offset Begin table
Example: After Interrupt
End of table
PC W BSR STATUS GIE/GIEH, PEIE/GIEL
= = = = =
TOS WS BSRS STATUSS 1
Before Instruction
W W = = 0x07 value of kn
After Instruction
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PIC18FXX20
RETURN Syntax: Operands: Operation: Return from Subroutine [ label ] s [0,1] (TOS) PC, if s = 1 (WS) W, (STATUSS) STATUS, (BSRS) BSR, PCLATU, PCLATH are unchanged None
0000 0000 0001 001s
RLCF Syntax: Operands:
Rotate Left f through Carry [ label ] RLCF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) dest, (f<7>) C, (C) dest<0> C, N, Z
0011 01da ffff ffff
RETURN [s]
Operation:
Status Affected: Encoding: Description:
Status Affected: Encoding: Description:
Return from subroutine. The stack is popped and the top of the stack (TOS) is loaded into the program counter. If `s'= 1, the contents of the shadow registers WS, STATUSS and BSRS are loaded into their corresponding registers, W, STATUS and BSR. If `s' = 0, no update of these registers occurs (default). 1 2 Q2
No operation No operation
The contents of register 'f' are rotated one bit to the left through the Carry Flag. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' = 1, then the bank will be selected as per the BSR value (default). C
register f
Words: Cycles: Q Cycle Activity: Q1
Decode No operation
Words: Q3
Process Data No operation
1 1 Q2
Read register 'f' RLCF = = = = =
Q4
pop PC from stack No operation
Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write to destination
Example: Example: After Interrupt
PC = TOS RETURN REG C REG W C
REG, 0, 0
Before Instruction
1110 0110 0 1110 0110 1100 1100 1
After Instruction
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PIC18FXX20
RLNCF Syntax: Operands: Rotate Left f (no carry) [ label ] RLNCF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) dest, (f<7>) dest<0> N, Z
0100 01da ffff ffff
RRCF Syntax: Operands:
Rotate Right f through Carry [ label ] RRCF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) dest, (f<0>) C, (C) dest<7> C, N, Z
0011 00da ffff ffff
Operation: Status Affected: Encoding: Description:
Operation:
Status Affected: Encoding: Description:
The contents of register 'f' are rotated one bit to the left. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default).
register f
The contents of register 'f' are rotated one bit to the right through the Carry Flag. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). C
register f
Words: Cycles: Q Cycle Activity: Q1
Decode
1 1 Q2
Read register 'f' RLNCF = =
Words: Q3
Process Data
1 1 Q2
Read register 'f' RRCF = = = = =
Q4
Write to destination
Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data REG, 0, 0
Q4
Write to destination
Example:
REG REG
REG, 1, 0
Before Instruction
1010 1011 0101 0111
Example:
REG C REG W C
After Instruction
Before Instruction
1110 0110 0 1110 0110 0111 0011 0
After Instruction
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PIC18FXX20
RRNCF Syntax: Operands: Rotate Right f (no carry) [ label ] RRNCF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f) dest, (f<0>) dest<7> N, Z
0100 00da ffff ffff
SETF Syntax: Operands: Operation: Status Affected: Encoding: Description:
Set f [label] SETF 0 f 255 a [0,1] FFh f None
0110 100a ffff ffff
f [,a]
Operation: Status Affected: Encoding: Description:
The contents of register 'f' are rotated one bit to the right. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default).
register f
The contents of the specified register are set to FFh. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' SETF = = 0x5A 0xFF
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data REG,1
Q4
Write register 'f'
Words: Cycles: Q Cycle Activity: Q1
Decode
1 1 Q2
Read register 'f' RRNCF = =
Example: Q3
Process Data REG, 1, 0
Before Instruction Q4
Write to destination REG
After Instruction
REG
Example 1:
REG REG
Before Instruction
1101 0111 1110 1011 RRNCF REG, 0, 0
After Instruction
Example 2:
W REG W REG = = = =
Before Instruction
? 1101 0111 1110 1011 1101 0111
After Instruction
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PIC18FXX20
SLEEP Syntax: Operands: Operation: Enter SLEEP mode [ label ] SLEEP None 00h WDT, 0 WDT postscaler, 1 TO, 0 PD TO, PD
0000 0000 0000 0011
SUBFWB Syntax: Operands:
Subtract f from W with borrow [ label ] SUBFWB 0 f 255 d [0,1] a [0,1] (W) - (f) - (C) dest N, OV, C, DC, Z
0101 01da ffff ffff
f [,d [,a]
Operation: Status Affected: Encoding: Description:
Status Affected: Encoding: Description:
The power-down status bit (PD) is cleared. The time-out status bit (TO) is set. Watchdog Timer and its postscaler are cleared. The processor is put into SLEEP mode with the oscillator stopped. 1 1 Q2
No operation SLEEP
Words: Cycles: Q Cycle Activity: Q1
Decode
Subtract register 'f' and carry flag (borrow) from W (2's complement method). If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' SUBFWB = = = = = = = = 3 2 1 FF 2 0 0 1 ; result is negative SUBFWB = = = = = = = = 2 5 1 2 3 1 0 0 REG, 0, 0
Words: Q3
Process Data
Q4
Go to sleep
Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data REG, 1, 0
Q4
Write to destination
Example:
TO = PD = TO = PD = ? ?
Before Instruction
Example 1:
REG W C REG W C Z N
Before Instruction
After Instruction
1 0
After Instruction
If WDT causes wake-up, this bit is cleared.
Example 2:
REG W C REG W C Z N
Before Instruction
After Instruction
; result is positive REG, 1, 0
Example 3:
REG W C REG W C Z N = = = = = = = =
SUBFWB 1 2 0 0 2 1 1 0
Before Instruction
After Instruction
; result is zero
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PIC18FXX20
SUBLW Syntax: Operands: Operation: Status Affected: Encoding: Description: Subtract W from literal [ label ] SUBLW k 0 k 255 k - (W) W N, OV, C, DC, Z
0000 1000 kkkk kkkk
SUBWF Syntax: Operands:
Subtract W from f [ label ] SUBWF 0 f 255 d [0,1] a [0,1] (f) - (W) dest N, OV, C, DC, Z
0101 11da ffff ffff
f [,d [,a]
Operation: Status Affected: Encoding: Description:
W is subtracted from the eight-bit literal 'k'. The result is placed in W. 1 1 Q2
Read literal 'k' SUBLW
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data 0x02
Q4
Write to W
Subtract W from register 'f' (2's complement method). If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' SUBWF = = = = = = = = 3 2 ? 1 2 1 0 0 SUBWF = = = = = = = = 2 2 ? 2 0 1 1 0 SUBWF = = = = = = = = 1 2 ? FFh ;(2's complement) 2 0 ; result is negative 0 1
Example 1:
W C W C Z N = = = = = =
Words: Cycles: Q Cycle Activity: Q1
Decode
Before Instruction
1 ? 1 1 0 0 SUBLW
After Instruction
; result is positive
Q3
Process Data REG, 1, 0
Q4
Write to destination
Example 1:
0x02 REG W C REG W C Z N
Example 2:
W C W C Z N = = = = = =
Before Instruction
Before Instruction
2 ? 0 1 1 0 SUBLW
After Instruction
; result is zero
After Instruction
; result is positive
Example 3:
W C W C Z N = = = = = =
0x02
Example 2:
REG W C REG W C Z N
REG, 0, 0
Before Instruction
3 ? FF ; (2's complement) 0 ; result is negative 0 1
Before Instruction
After Instruction
After Instruction
; result is zero
Example 3:
REG W C REG W C Z N
REG, 1, 0
Before Instruction
After Instruction
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PIC18FXX20
SUBWFB Syntax: Operands: Subtract W from f with Borrow [ label ] SUBWFB 0 f 255 d [0,1] a [0,1] (f) - (W) - (C) dest N, OV, C, DC, Z
0101 10da ffff ffff
SWAPF Syntax: Operands:
Swap f [ label ] SWAPF f [,d [,a] 0 f 255 d [0,1] a [0,1] (f<3:0>) dest<7:4>, (f<7:4>) dest<3:0> None
0011 10da ffff ffff
f [,d [,a]
Operation: Status Affected: Encoding: Description:
Operation: Status Affected: Encoding: Description:
Subtract W and the carry flag (borrow) from register 'f' (2's complement method). If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' SUBWFB = = = = = = = = 0x19 0x0D 1 0x0C 0x0D 1 0 0
Words: Cycles: Q Cycle Activity: Q1
Decode
The upper and lower nibbles of register 'f' are exchanged. If 'd' is 0, the result is placed in W. If 'd' is 1, the result is placed in register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' SWAPF = = 0x53 0x35
Words: Cycles: Q3
Process Data REG, 1, 0
Q4
Write to destination
Q Cycle Activity: Q1
Decode
Q3
Process Data REG, 1, 0
Q4
Write to destination
Example 1:
REG W C REG W C Z N
Before Instruction
(0001 1001) (0000 1101)
Example:
REG REG
Before Instruction After Instruction
After Instruction
(0000 1011) (0000 1101) ; result is positive
Example 2:
REG W C REG W C Z N = = = = = = = =
SUBWFB REG, 0, 0 0x1B 0x1A 0 0x1B 0x00 1 1 0 SUBWFB = = = = = = = = 0x03 0x0E 1 0xF5 0x0E 0 0 1
Before Instruction
(0001 1011) (0001 1010)
After Instruction
(0001 1011) ; result is zero REG, 1, 0
Example 3:
REG W C REG W C Z N
Before Instruction
(0000 0011) (0000 1101)
After Instruction
(1111 0100) ; [2's comp] (0000 1101) ; result is negative
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PIC18FXX20
TBLRD Syntax: Operands: Operation: Table Read [ label ] None if TBLRD *, (Prog Mem (TBLPTR)) TABLAT; TBLPTR - No Change; if TBLRD *+, (Prog Mem (TBLPTR)) TABLAT; (TBLPTR) +1 TBLPTR; if TBLRD *-, (Prog Mem (TBLPTR)) TABLAT; (TBLPTR) -1 TBLPTR; if TBLRD +*, (TBLPTR) +1 TBLPTR; (Prog Mem (TBLPTR)) TABLAT;
0000 0000 0000 10nn nn=0 * =1 *+ =2 *=3 +*
TBLRD Example1:
Table Read (cont'd)
TBLRD *+ ; = = = = = TBLRD +* ; = = = = = = 0xAA 0x01A357 0x12 0x34 0x34 0x01A358 0x55 0x00A356 0x34 0x34 0x00A357
TBLRD ( *; *+; *-; +*)
Before Instruction
TABLAT TBLPTR MEMORY(0x00A356)
After Instruction
TABLAT TBLPTR
Example2:
Before Instruction
TABLAT TBLPTR MEMORY(0x01A357) MEMORY(0x01A358)
Status Affected:None Encoding:
After Instruction
TABLAT TBLPTR
Description:
This instruction is used to read the contents of Program Memory (P.M.). To address the program memory, a pointer called Table Pointer (TBLPTR) is used. The TBLPTR (a 21-bit pointer) points to each byte in the program memory. TBLPTR has a 2-Mbyte address range. TBLPTR[0] = 0: Least Significant Byte of Program Memory Word TBLPTR[0] = 1: Most Significant Byte of Program Memory Word The TBLRD instruction can modify the value of TBLPTR as follows: * no change * post-increment * post-decrement * pre-increment 1 2 Q2
No operation No operation (Read Program Memory)
Words: Cycles:
Q Cycle Activity: Q1
Decode No operation
Q3
No operation
Q4
No operation
No No operation operation (Write TABLAT)
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PIC18FXX20
TBLWT Syntax: Operands: Operation: Table Write [ label ] TBLWT ( *; *+; *-; +*) None if TBLWT*, (TABLAT) Holding Register; TBLPTR - No Change; if TBLWT*+, (TABLAT) Holding Register; (TBLPTR) +1 TBLPTR; if TBLWT*-, (TABLAT) Holding Register; (TBLPTR) -1 TBLPTR; if TBLWT+*, (TBLPTR) +1 TBLPTR; (TABLAT) Holding Register;
0000 0000 0000 11nn nn=0 * =1 *+ =2 *=3 +*
TBLWT Table Write (Continued) Words: 1 Cycles: 2 Q Cycle Activity: Q1
Decode No operation
Q2
No operation No operation (Read TABLAT)
Q3
No operation No operation
Q4
No operation No operation (Write to Holding Register )
Status Affected: None Encoding:
Example1:
TBLWT
*+;
= = = = = = 0x55 0x00A356 0xFF 0x55 0x00A357 0x55
Before Instruction
TABLAT TBLPTR HOLDING REGISTER (0x00A356) TABLAT TBLPTR HOLDING REGISTER (0x00A356)
After Instructions (table write completion)
Description:
This instruction uses the 3 LSBs of TBLPTR to determine which of the 8 holding registers the TABLAT is written to. The holding registers are used to program the contents of Program Memory (P.M.). (Refer to Section 5.0 for additional details on programming FLASH memory.) The TBLPTR (a 21-bit pointer) points to each byte in the program memory. TBLPTR has a 2-MByte address range. The LSb of the TBLPTR selects which byte of the program memory location to access. TBLPTR[0] = 0:Least Significant Byte of Program Memory Word TBLPTR[0] = 1:Most Significant Byte of Program Memory Word The TBLWT instruction can modify the value of TBLPTR as follows: * no change * post-increment * post-decrement * pre-increment
Example 2:
TBLWT
+*;
= = = = = = = = 0x34 0x01389A 0xFF 0xFF 0x34 0x01389B 0xFF 0x34
Before Instruction
TABLAT TBLPTR HOLDING REGISTER (0x01389A) HOLDING REGISTER (0x01389B) TABLAT TBLPTR HOLDING REGISTER (0x01389A) HOLDING REGISTER (0x01389B)
After Instruction (table write completion)
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2003 Microchip Technology Inc.
PIC18FXX20
TSTFSZ Syntax: Operands: Operation: Status Affected: Encoding: Description: Test f, skip if 0 [ label ] TSTFSZ f [,a] 0 f 255 a [0,1] skip if f = 0 None
0110 011a ffff ffff
XORLW Syntax: Operands: Operation: Status Affected: Encoding: Description:
Exclusive OR literal with W [ label ] XORLW k 0 k 255 (W) .XOR. k W N, Z
0000 1010 kkkk kkkk
If 'f' = 0, the next instruction, fetched during the current instruction execution, is discarded and a NOP is executed, making this a two-cycle instruction. If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1(2) Note: 3 cycles if skip and followed by a 2-word instruction. Q2
Read register 'f'
The contents of W are XORed with the 8-bit literal 'k'. The result is placed in W. 1 1 Q2
Read literal 'k'
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
Write to W
Words: Cycles:
Example:
W W = =
XORLW 0xAF
0xB5 0x1A
Before Instruction After Instruction
Q Cycle Activity: Q1
Decode
Q3
Process Data
Q4
No operation
If skip: Q1
No operation
Q2
No operation
Q3
No operation
Q4
No operation
If skip and followed by 2-word instruction: Q1 Q2 Q3
No operation No operation No operation No operation HERE NZERO ZERO = = = = No operation No operation TSTFSZ : :
Q4
No operation No operation
Example:
CNT, 1
Before Instruction
PC Address (HERE) 0x00, Address (ZERO) 0x00, Address (NZERO)
After Instruction
If CNT PC If CNT PC
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 299
PIC18FXX20
XORWF Syntax: Operands: Exclusive OR W with f [ label ] XORWF 0 f 255 d [0,1] a [0,1] (W) .XOR. (f) dest N, Z
0001 10da ffff ffff
f [,d [,a]
Operation: Status Affected: Encoding: Description:
Exclusive OR the contents of W with register 'f'. If 'd' is 0, the result is stored in W. If 'd' is 1, the result is stored back in the register 'f' (default). If `a' is 0, the Access Bank will be selected, overriding the BSR value. If `a' is 1, then the bank will be selected as per the BSR value (default). 1 1 Q2
Read register 'f' XORWF = = = = 0xAF 0xB5 0x1A 0xB5
Words: Cycles: Q Cycle Activity: Q1
Decode
Q3
Process Data REG, 1, 0
Q4
Write to destination
Example:
REG W REG W
Before Instruction
After Instruction
DS39609A-page 300
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PIC18FXX20
25.0 DEVELOPMENT SUPPORT
25.1
The PICmicro(R) microcontrollers are supported with a full range of hardware and software development tools: * Integrated Development Environment - MPLAB(R) IDE Software * Assemblers/Compilers/Linkers - MPASMTM Assembler - MPLAB C17 and MPLAB C18 C Compilers - MPLINKTM Object Linker/ MPLIBTM Object Librarian - MPLAB C30 C Compiler - MPLAB ASM30 Assembler/Linker/Library * Simulators - MPLAB SIM Software Simulator - MPLAB dsPIC30 Software Simulator * Emulators - MPLAB ICE 2000 In-Circuit Emulator - MPLAB ICE 4000 In-Circuit Emulator * In-Circuit Debugger - MPLAB ICD 2 * Device Programmers - PRO MATE(R) II Universal Device Programmer - PICSTART(R) Plus Development Programmer * Low Cost Demonstration Boards - PICDEMTM 1 Demonstration Board - PICDEM.netTM Demonstration Board - PICDEM 2 Plus Demonstration Board - PICDEM 3 Demonstration Board - PICDEM 17 Demonstration Board - PICDEM 18R Demonstration Board - PICDEM LIN Demonstration Board - PICDEM USB Demonstration Board * Evaluation Kits - KEELOQ(R) - PICDEM MSC - microID(R) - CAN - PowerSmart(R) - Analog
MPLAB Integrated Development Environment Software
The MPLAB IDE software brings an ease of software development previously unseen in the 8/16-bit microcontroller market. The MPLAB IDE is a Windows(R) based application that contains: * An interface to debugging tools - simulator - programmer (sold separately) - emulator (sold separately) - in-circuit debugger (sold separately) * A full-featured editor with color coded context * A multiple project manager * Customizable data windows with direct edit of contents * High level source code debugging * Mouse over variable inspection * Extensive on-line help The MPLAB IDE allows you to: * Edit your source files (either assembly or C) * One touch assemble (or compile) and download to PICmicro emulator and simulator tools (automatically updates all project information) * Debug using: - source files (assembly or C) - absolute listing file (mixed assembly and C) - machine code MPLAB IDE supports multiple debugging tools in a single development paradigm, from the cost effective simulators, through low cost in-circuit debuggers, to full-featured emulators. This eliminates the learning curve when upgrading to tools with increasing flexibility and power.
25.2
MPASM Assembler
The MPASM assembler is a full-featured, universal macro assembler for all PICmicro MCUs. The MPASM assembler generates relocatable object files for the MPLINK object linker, Intel(R) standard HEX files, MAP files to detail memory usage and symbol reference, absolute LST files that contains source lines and generated machine code and COFF files for debugging. The MPASM assembler features include: * * * * Integration into MPLAB IDE projects User defined macros to streamline assembly code Conditional assembly for multi-purpose source files Directives that allow complete control over the assembly process
2003 Microchip Technology Inc.
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PIC18FXX20
25.3 MPLAB C17 and MPLAB C18 C Compilers 25.6 MPLAB ASM30 Assembler, Linker, and Librarian
The MPLAB C17 and MPLAB C18 Code Development Systems are complete ANSI C compilers for Microchip's PIC17CXXX and PIC18CXXX family of microcontrollers. These compilers provide powerful integration capabilities, superior code optimization and ease of use not found with other compilers. For easy source level debugging, the compilers provide symbol information that is optimized to the MPLAB IDE debugger.
MPLAB ASM30 assembler produces relocatable machine code from symbolic assembly language for dsPIC30F devices. MPLAB C30 compiler uses the assembler to produce it's object file. The assembler generates relocatable object files that can then be archived or linked with other relocatable object files and archives to create an executable file. Notable features of the assembler include: * * * * * * Support for the entire dsPIC30F instruction set Support for fixed-point and floating-point data Command line interface Rich directive set Flexible macro language MPLAB IDE compatibility
25.4
MPLINK Object Linker/ MPLIB Object Librarian
The MPLINK object linker combines relocatable objects created by the MPASM assembler and the MPLAB C17 and MPLAB C18 C compilers. It can link relocatable objects from pre-compiled libraries, using directives from a linker script. The MPLIB object librarian manages the creation and modification of library files of pre-compiled code. When a routine from a library is called from a source file, only the modules that contain that routine will be linked in with the application. This allows large libraries to be used efficiently in many different applications. The object linker/library features include: * Efficient linking of single libraries instead of many smaller files * Enhanced code maintainability by grouping related modules together * Flexible creation of libraries with easy module listing, replacement, deletion and extraction
25.7
MPLAB SIM Software Simulator
The MPLAB SIM software simulator allows code development in a PC hosted environment by simulating the PICmicro series microcontrollers on an instruction level. On any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any pin. The execution can be performed in Single-Step, Execute Until Break, or Trace mode. The MPLAB SIM simulator fully supports symbolic debugging using the MPLAB C17 and MPLAB C18 C Compilers, as well as the MPASM assembler. The software simulator offers the flexibility to develop and debug code outside of the laboratory environment, making it an excellent, economical software development tool.
25.5
MPLAB C30 C Compiler
25.8
MPLAB SIM30 Software Simulator
The MPLAB C30 C compiler is a full-featured, ANSI compliant, optimizing compiler that translates standard ANSI C programs into dsPIC30F assembly language source. The compiler also supports many commandline options and language extensions to take full advantage of the dsPIC30F device hardware capabilities, and afford fine control of the compiler code generator. MPLAB C30 is distributed with a complete ANSI C standard library. All library functions have been validated and conform to the ANSI C library standard. The library includes functions for string manipulation, dynamic memory allocation, data conversion, timekeeping, and math functions (trigonometric, exponential and hyperbolic). The compiler provides symbolic information for high level source debugging with the MPLAB IDE.
The MPLAB SIM30 software simulator allows code development in a PC hosted environment by simulating the dsPIC30F series microcontrollers on an instruction level. On any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any of the pins. The MPLAB SIM30 simulator fully supports symbolic debugging using the MPLAB C30 C Compiler and MPLAB ASM30 assembler. The simulator runs in either a Command Line mode for automated tasks, or from MPLAB IDE. This high speed simulator is designed to debug, analyze and optimize time intensive DSP routines.
DS39609A-page 302
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PIC18FXX20
25.9 MPLAB ICE 2000 High Performance Universal In-Circuit Emulator 25.11 MPLAB ICD 2 In-Circuit Debugger
Microchip's In-Circuit Debugger, MPLAB ICD 2, is a powerful, low cost, run-time development tool, connecting to the host PC via an RS-232 or high speed USB interface. This tool is based on the FLASH PICmicro MCUs and can be used to develop for these and other PICmicro microcontrollers. The MPLAB ICD 2 utilizes the in-circuit debugging capability built into the FLASH devices. This feature, along with Microchip's In-Circuit Serial ProgrammingTM (ICSPTM) protocol, offers cost effective in-circuit FLASH debugging from the graphical user interface of the MPLAB Integrated Development Environment. This enables a designer to develop and debug source code by setting breakpoints, single-stepping and watching variables, CPU status and peripheral registers. Running at full speed enables testing hardware and applications in real-time. MPLAB ICD 2 also serves as a development programmer for selected PICmicro devices.
The MPLAB ICE 2000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for PICmicro microcontrollers. Software control of the MPLAB ICE 2000 in-circuit emulator is advanced by the MPLAB Integrated Development Environment, which allows editing, building, downloading and source debugging from a single environment. The MPLAB ICE 2000 is a full-featured emulator system with enhanced trace, trigger and data monitoring features. Interchangeable processor modules allow the system to be easily reconfigured for emulation of different processors. The universal architecture of the MPLAB ICE in-circuit emulator allows expansion to support new PICmicro microcontrollers. The MPLAB ICE 2000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. The PC platform and Microsoft(R) Windows 32-bit operating system were chosen to best make these features available in a simple, unified application.
25.12 PRO MATE II Universal Device Programmer
The PRO MATE II is a universal, CE compliant device programmer with programmable voltage verification at VDDMIN and VDDMAX for maximum reliability. It features an LCD display for instructions and error messages and a modular detachable socket assembly to support various package types. In Stand-Alone mode, the PRO MATE II device programmer can read, verify, and program PICmicro devices without a PC connection. It can also set code protection in this mode.
25.10 MPLAB ICE 4000 High Performance Universal In-Circuit Emulator
The MPLAB ICE 4000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for highend PICmicro microcontrollers. Software control of the MPLAB ICE in-circuit emulator is provided by the MPLAB Integrated Development Environment, which allows editing, building, downloading and source debugging from a single environment. The MPLAB ICD 4000 is a premium emulator system, providing the features of MPLAB ICE 2000, but with increased emulation memory and high speed performance for dsPIC30F and PIC18XXXX devices. Its advanced emulator features include complex triggering and timing, up to 2 Mb of emulation memory, and the ability to view variables in real-time. The MPLAB ICE 4000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. The PC platform and Microsoft Windows 32-bit operating system were chosen to best make these features available in a simple, unified application.
25.13 PICSTART Plus Development Programmer
The PICSTART Plus development programmer is an easy-to-use, low cost, prototype programmer. It connects to the PC via a COM (RS-232) port. MPLAB Integrated Development Environment software makes using the programmer simple and efficient. The PICSTART Plus development programmer supports most PICmicro devices up to 40 pins. Larger pin count devices, such as the PIC16C92X and PIC17C76X, may be supported with an adapter socket. The PICSTART Plus development programmer is CE compliant.
2003 Microchip Technology Inc.
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PIC18FXX20
25.14 PICDEM 1 PICmicro Demonstration Board
The PICDEM 1 demonstration board demonstrates the capabilities of the PIC16C5X (PIC16C54 to PIC16C58A), PIC16C61, PIC16C62X, PIC16C71, PIC16C8X, PIC17C42, PIC17C43 and PIC17C44. All necessary hardware and software is included to run basic demo programs. The sample microcontrollers provided with the PICDEM 1 demonstration board can be programmed with a PRO MATE II device programmer, or a PICSTART Plus development programmer. The PICDEM 1 demonstration board can be connected to the MPLAB ICE in-circuit emulator for testing. A prototype area extends the circuitry for additional application components. Features include an RS-232 interface, a potentiometer for simulated analog input, push button switches and eight LEDs.
25.16 PICDEM 2 Plus Demonstration Board
The PICDEM 2 Plus demonstration board supports many 18-, 28-, and 40-pin microcontrollers, including PIC16F87X and PIC18FXX2 devices. All the necessary hardware and software is included to run the demonstration programs. The sample microcontrollers provided with the PICDEM 2 demonstration board can be programmed with a PRO MATE II device programmer, PICSTART Plus development programmer, or MPLAB ICD 2 with a Universal Programmer Adapter. The MPLAB ICD 2 and MPLAB ICE in-circuit emulators may also be used with the PICDEM 2 demonstration board to test firmware. A prototype area extends the circuitry for additional application components. Some of the features include an RS-232 interface, a 2 x 16 LCD display, a piezo speaker, an on-board temperature sensor, four LEDs, and sample PIC18F452 and PIC16F877 FLASH microcontrollers.
25.15 PICDEM.net Internet/Ethernet Demonstration Board
The PICDEM.net demonstration board is an Internet/ Ethernet demonstration board using the PIC18F452 microcontroller and TCP/IP firmware. The board supports any 40-pin DIP device that conforms to the standard pinout used by the PIC16F877 or PIC18C452. This kit features a user friendly TCP/IP stack, web server with HTML, a 24L256 Serial EEPROM for Xmodem download to web pages into Serial EEPROM, ICSP/MPLAB ICD 2 interface connector, an Ethernet interface, RS-232 interface, and a 16 x 2 LCD display. Also included is the book and CD-ROM "TCP/IP Lean, Web Servers for Embedded Systems," by Jeremy Bentham
25.17 PICDEM 3 PIC16C92X Demonstration Board
The PICDEM 3 demonstration board supports the PIC16C923 and PIC16C924 in the PLCC package. All the necessary hardware and software is included to run the demonstration programs.
25.18 PICDEM 17 Demonstration Board
The PICDEM 17 demonstration board is an evaluation board that demonstrates the capabilities of several Microchip microcontrollers, including PIC17C752, PIC17C756A, PIC17C762 and PIC17C766. A programmed sample is included. The PRO MATE II device programmer, or the PICSTART Plus development programmer, can be used to reprogram the device for user tailored application development. The PICDEM 17 demonstration board supports program download and execution from external on-board FLASH memory. A generous prototype area is available for user hardware expansion.
DS39609A-page 304
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PIC18FXX20
25.19 PICDEM 18R PIC18C601/801 Demonstration Board
The PICDEM 18R demonstration board serves to assist development of the PIC18C601/801 family of Microchip microcontrollers. It provides hardware implementation of both 8-bit Multiplexed/De-multiplexed and 16-bit Memory modes. The board includes 2 Mb external FLASH memory and 128 Kb SRAM memory, as well as serial EEPROM, allowing access to the wide range of memory types supported by the PIC18C601/801.
25.21 PICDEM USB PIC16C7X5 Demonstration Board
The PICDEM USB Demonstration Board shows off the capabilities of the PIC16C745 and PIC16C765 USB microcontrollers. This board provides the basis for future USB products.
25.22 Evaluation and Programming Tools
In addition to the PICDEM series of circuits, Microchip has a line of evaluation kits and demonstration software for these products. * KEELOQ evaluation and programming tools for Microchip's HCS Secure Data Products * CAN developers kit for automotive network applications * Analog design boards and filter design software * PowerSmart battery charging evaluation/ calibration kits * IrDA(R) development kit * microID development and RFLabTM development software * SEEVAL(R) designer kit for memory evaluation and endurance calculations * PICDEM MSC demo boards for Switching mode power supply, high power IR driver, delta sigma ADC, and flow rate sensor Check the Microchip web page and the latest Product Line Card for the complete list of demonstration and evaluation kits.
25.20 PICDEM LIN PIC16C43X Demonstration Board
The powerful LIN hardware and software kit includes a series of boards and three PICmicro microcontrollers. The small footprint PIC16C432 and PIC16C433 are used as slaves in the LIN communication and feature on-board LIN transceivers. A PIC16F874 FLASH microcontroller serves as the master. All three microcontrollers are programmed with firmware to provide LIN bus communication.
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 305
PIC14000
PI18CX01
PIC16C5X
PIC16C6X
PIC16C7X
PIC16C8X
PIC16C43X
PIC16F62X
PIC16C7X5
PIC12FXXX
PIC16C7XX
PIC16F8XX
PIC16C9XX
PIC17C4X
PIC17C7XX
PIC18CXX2
PIC12CXXX
PIC16CXXX
PIC18FXXX dsPIC30F
TABLE 25-1:
Software Tools
Programmers Debugger Emulators
Demo Boards and Eval Kits
DS39609A-page 306 ** * * ** **
MPLAB Integrated Development Environment
MPLAB C17 C Compiler
MPLAB C18 C Compiler
MPASM Assembler/ MPLINK Object Linker
PIC18FXX20
MPLAB C30 C Compiler
MPLAB ASM30 Assembler/Linker/Librarian
MPLAB ICE 2000 In-Circuit Emulator
MPLAB ICE 4000 In-Circuit Emulator
MPLAB ICD 2 In-Circuit Debugger
PICSTART Plus Entry Level Development Programmer
DEVELOPMENT TOOLS FROM MICROCHIP
PRO MATE II Universal Device Programmer
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PICDEM 1 Demonstration Board
PICDEM.net Demonstration Board
PICDEM 2 Plus Demonstration Board
PICDEM 3 Demonstration Board
PICDEM 14A Demonstration Board
PICDEM 17 Demonstration Board
PICDEM 18R Demonstration Board
PICDEM LIN Demonstration Board
PICDEM USB Demonstration Board
2003 Microchip Technology Inc.
* Contact the Microchip web site at www.microchip.com for information on how to use the MPLAB ICD In-Circuit Debugger (DV164001) with PIC16C62, 63, 64, 65, 72, 73, 74, 76, 77. ** Contact Microchip Technology Inc. for availability date. Development tool is available on select devices.
PIC18FXX20
26.0 ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings () Ambient temperature under bias.............................................................................................................-55C to +125C Storage temperature .............................................................................................................................. -65C to +150C Voltage on any pin with respect to VSS (except VDD, MCLR, and RA4) ......................................... -0.3V to (VDD + 0.3V) Voltage on VDD with respect to VSS ......................................................................................................... -0.3V to +5.5V Voltage on MCLR with respect to VSS (Note 2) ......................................................................................... 0V to +13.25V Voltage on RA4 with respect to Vss ............................................................................................................. 0V to +12.0V Total power dissipation (Note 1) ...............................................................................................................................1.0W Maximum current out of VSS pin ...........................................................................................................................300 mA Maximum current into VDD pin ..............................................................................................................................250 mA Input clamp current, IIK (VI < 0 or VI > VDD)...................................................................................................................... 20 mA Output clamp current, IOK (VO < 0 or VO > VDD) .............................................................................................................. 20 mA Maximum output current sunk by any I/O pin..........................................................................................................25 mA Maximum output current sourced by any I/O pin ....................................................................................................25 mA Maximum current sunk by all ports .......................................................................................................................200 mA Maximum current sourced by all ports ..................................................................................................................200 mA Note 1: Power dissipation is calculated as follows: Pdis = VDD x {IDD - IOH} + {(VDD-VOH) x IOH} + (VOl x IOL) 2: Voltage spikes below VSS at the MCLR/VPP pin, inducing currents greater than 80 mA, may cause latchup. Thus, a series resistor of 50-100 should be used when applying a "low" level to the MCLR/VPP pin, rather than pulling this pin directly to VSS.
NOTICE: Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.
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PIC18FXX20
FIGURE 26-1: PIC18F6520/8520 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V 5.5V 5.0V PIC18FX520 4.2V 4.5V 4.0V 3.5V 3.0V 2.5V 2.0V
Voltage
40 MHz
Frequency
FIGURE 26-2:
PIC18LF6520/8520 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL) 6.0V 5.5V 5.0V 4.5V 4.0V 3.5V 3.0V 2.5V 2.0V PIC18LFX520 4.2V
Voltage
4 MHz
40 MHz
Frequency
FMAX = (16.36 MHz/V) (VDDAPPMIN - 2.0V) + 4 MHz Note: VDDAPPMIN is the minimum voltage of the PICmicro(R) device in the application.
DS39609A-page 308
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PIC18FXX20
FIGURE 26-3: PIC18F6620/6720/8620/8720 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL, EXTENDED)
6.0V 5.5V 5.0V PIC18FX620/X720 4.2V 4.5V 4.0V 3.5V 3.0V 2.5V 2.0V
Voltage
Frequency
25 MHz
FIGURE 26-4:
PIC18LF6620/6720/8620/8720 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V 5.5V 5.0V 4.5V 4.0V 3.5V 3.0V 2.5V 2.0V PIC18LFX620/X720 4.2V
Voltage
4 MHz
Frequency
25 MHz
FMAX = (9.55 MHz/V) (VDDAPPMIN - 2.0V) + 4 MHz Note: VDDAPPMIN is the minimum voltage of the PICmicro(R) device in the application.
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DS39609A-page 309
PIC18FXX20
26.1 DC Characteristics: Supply Voltage PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Min Typ Max Units Conditions
PIC18LFXX20 (Industrial) PIC18FXX20 (Industrial, Extended) Param Symbol No. VDD D001 D001A AVDD D002 D003 VDR VPOR Characteristic Supply Voltage PIC18LFXX20 PIC18FXX20 Analog Supply Voltage RAM Data Retention Voltage(1) VDD Start Voltage to ensure internal Power-on Reset signal VDD Rise Rate to ensure internal Power-on Reset signal Brown-out Reset Voltage BORV1:BORV0 = 11 BORV1:BORV0 = 10 BORV1:BORV0 = 01 BORV1:BORV0 = 00
2.0 4.2 VDD - 0.3 1.5 --
-- -- -- -- --
5.5 5.5 VDD + 0.3 -- 0.7
V V V V V
HS, XT, RC and LP Osc mode
See section on Power-on Reset for details
D004
SVDD
0.05
--
--
V/ms See section on Power-on Reset for details
VBOR D005
2.00 2.70 4.20 4.50
-- -- -- --
2.16 2.86 4.46 4.78
V V V V
Legend: Shading of rows is to assist in readability of the table. Note 1: This is the limit to which VDD can be lowered in SLEEP mode, or during a device RESET, without losing RAM data.
DS39609A-page 310
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PIC18FXX20
26.2 DC Characteristics: Power-down and Supply Current PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Typ Max Units Conditions
PIC18LFXX20 (Industrial) PIC18FXX20 (Industrial, Extended) Param No. Device
Power-down Current (IPD)(1) PIC18LFXX20 0.2 0.2 1.2 PIC18LFXX20 0.4 0.4 1.8 All devices 0.7 0.7 3.0 1 1 5 1 1 8 2 2 15 A A A A A A A A A -40C 25C 85C -40C 25C 85C -40C 25C 85C VDD = 5.0V, (SLEEP mode) VDD = 3.0V, (SLEEP mode) VDD = 2.0V, (SLEEP mode)
Legend: Shading of rows is to assist in readability of the table. Note 1: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is measured with the part in SLEEP mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.). 2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. The test conditions for all IDD measurements in active Operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT enabled/disabled as specified. 3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
2003 Microchip Technology Inc.
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DS39609A-page 311
PIC18FXX20
26.2 DC Characteristics: Power-down and Supply Current PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Typ Max Units Conditions
PIC18LFXX20 (Industrial) PIC18FXX20 (Industrial, Extended) Param No. Device Supply Current (IDD)(2,3) PIC18LFXX20
165 165 170
350 350 350 750 750 750 1700 1700 1700 1200 1200 1300 2500 2500 2500 5.0 5.0 5.0
A A A A A A A A A A A A A A A mA mA mA
-40C 25C 85C -40C 25C 85C -40C 25C 85C -40C 25C 85C -40C 25C 85C -40C 25C 85C VDD = 5.0V VDD = 3.0V FOSC = 4 MHz, EC oscillator VDD = 2.0V VDD = 5.0V VDD = 3.0V FOSC = 1 MHZ, EC oscillator VDD = 2.0V
PIC18LFXX20
360 340 300
All devices
800 730 700
PIC18LFXX20
600 600 640
PIC18LFXX20 1000 1000 1000 All devices 2.2 2.1 2.0
Legend: Shading of rows is to assist in readability of the table. Note 1: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is measured with the part in SLEEP mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.). 2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. The test conditions for all IDD measurements in active Operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT enabled/disabled as specified. 3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
DS39609A-page 312
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PIC18FXX20
26.2 DC Characteristics: Power-down and Supply Current PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Typ Max Units Conditions
PIC18LFXX20 (Industrial) PIC18FXX20 (Industrial, Extended) Param No. Device Supply Current (IDD)(2,3) PIC18FX620, PIC18FX720
9.3 9.5 10 11.8 12 12 TBD TBD TBD
15 15 15 20 20 20 TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD TBD
mA mA mA mA mA mA mA mA mA mA mA mA A A A A A A A A A
-40C 25C 85C -40C 25C 85C -40C 25C 85C -40C 25C 85C -10C 25C 70C -10C 25C 70C -10C 25C 70C VDD = 5.0V VDD = 3.0V FOSC = 32 kHz, Timer1 as clock VDD = 2.0V VDD = 5.0V VDD = 4.2V FOSC = 40 MHZ, EC oscillator VDD = 5.0V VDD = 4.2V FOSC = 25 MHZ, EC oscillator
PIC18FX620, PIC18FX720
PIC18FX520
PIC18FX520
TBD TBD TBD
PIC18LFXX20
TBD TBD TBD
PIC18LFXX20
TBD TBD TBD
All devices
TBD TBD TBD
Legend: Shading of rows is to assist in readability of the table. Note 1: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is measured with the part in SLEEP mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.). 2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. The test conditions for all IDD measurements in active Operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT enabled/disabled as specified. 3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
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PIC18FXX20
26.2 DC Characteristics: Power-down and Supply Current PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Typ Max Units Conditions
PIC18LFXX20 (Industrial) PIC18FXX20 (Industrial, Extended) Param No. D022 (IWDT) Device
Module Differential Currents (IWDT, IBOR, ILVD, IOSCB, IAD) Watchdog Timer <1 <1 <1 3 2.5 3 15 12 12 D022A (IBOR) D022B (ILVD) D025 (IOSCB) Timer1 Oscillator Low Voltage Detect Brown-out Reset 35 45 33 35 45 TBD TBD TBD TBD TBD TBD TBD TBD TBD D026 (IAD) A/D Converter <1 <1 <1 2.0 1.5 3 10 6 15 25 20 25 50 65 45 50 65 TBD TBD TBD TBD TBD TBD TBD TBD TBD 2 2 2 A A A A A A A A A A A A A A A A A A A A A A A A A A -40C 25C 85C -40C 25C 85C -40C 25C 85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -10C 25C 70C -10C 25C 70C -10C 25C 70C 25C 25C 25C VDD = 2.0V VDD = 3.0V VDD = 5.0V A/D on, not converting VDD = 5.0V 32 kHz on Timer1 VDD = 3.0V 32 kHz on Timer1 VDD = 2.0V 32 kHz on Timer1 VDD = 3.0V VDD = 5.0V VDD = 2.0V VDD = 3.0V VDD = 5.0V VDD = 5.0V VDD = 3.0V VDD = 2.0V
Legend: Shading of rows is to assist in readability of the table. Note 1: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is measured with the part in SLEEP mode, with all I/O pins in high-impedance state and tied to VDD or VSS, and all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.). 2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. The test conditions for all IDD measurements in active Operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT enabled/disabled as specified. 3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
DS39609A-page 314
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PIC18FXX20
26.3 DC Characteristics: PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Characteristic Input Low Voltage I/O ports: D030 D030A D031 D032 D032A D033 VIH D040 D040A D041 D042 D042A D043 IIL D060 D061 D063 IPU D070 IPURB with Schmitt Trigger buffer RC3 and RC4 MCLR, OSC1 (EC mode) OSC1 (in XT, HS and LP modes) and T1OSI OSC1 (RC mode)(1) Input Leakage Current(2,3) I/O ports MCLR OSC1 Weak Pull-up Current PORTB weak pull-up current 50 400 A VDD = 5V, VPIN = VSS -- -- -- 1 5 5 A A A VSS VPIN VDD, Pin at hi-impedance Vss VPIN VDD Vss VPIN VDD with Schmitt Trigger buffer RC3 and RC4 MCLR OSC1 (in XT, HS and LP modes) and T1OSI OSC1 (in RC and EC mode)(1) Input High Voltage I/O ports: with TTL buffer 0.25 VDD + 0.8V 2.0 0.8 VDD 0.7 VDD 0.8 VDD 0.7 VDD 0.9 VDD VDD VDD VDD VDD VDD VDD VDD V V V V V V V VDD < 4.5V 4.5V VDD 5.5V with TTL buffer VSS -- VSS VSS VSS VSS VSS 0.15 VDD 0.8 0.2 VDD 0.3 VDD 0.2 VDD 0.3 VDD 0.2 VDD V V V V V V V VDD < 4.5V 4.5V VDD 5.5V Min Max Units Conditions
DC CHARACTERISTICS Param Symbol No. VIL
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the PICmicro device be driven with an external clock while in RC mode. 2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages. 3: Negative current is defined as current sourced by the pin. 4: Parameter is characterized but not tested.
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PIC18FXX20
26.3 DC Characteristics: PIC18FXX20 (Industrial, Extended) PIC18LFXX20 (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Characteristic Output Low Voltage I/O ports -- -- OSC2/CLKO (RC mode) -- -- VOH D090 D090A D092 D092A D150 VOD Open Drain High Voltage Capacitive Loading Specs on Output Pins D100(4) COSC2 OSC2 pin -- 15 pF In XT, HS and LP modes when external clock is used to drive OSC1 To meet the AC Timing Specifications In I2C mode OSC2/CLKO (RC mode) Output High Voltage(3) I/O ports VDD - 0.7 VDD - 0.7 VDD - 0.7 VDD - 0.7 -- -- -- -- -- 8.5 V V V V V IOH = -3.0 mA, VDD = 4.5V, -40C to +85C IOH = -2.5 mA, VDD = 4.5V, -40C to +125C IOH = -1.3 mA, VDD = 4.5V, -40C to +85C IOH = -1.0 mA, VDD = 4.5V, -40C to +125C RA4 pin 0.6 0.6 0.6 0.6 V V V V IOL = 8.5 mA, VDD = 4.5V, -40C to +85C IOL = 7.0 mA, VDD = 4.5V, -40C to +125C IOL = 1.6 mA, VDD = 4.5V, -40C to +85C IOL = 1.2 mA, VDD = 4.5V, -40C to +125C Min Max Units Conditions
DC CHARACTERISTICS Param Symbol No. VOL D080 D080A D083 D083A
D101 D102
CIO CB
All I/O pins and OSC2 (in RC mode) SCL, SDA
-- --
50 400
pF pF
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the PICmicro device be driven with an external clock while in RC mode. 2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages. 3: Negative current is defined as current sourced by the pin. 4: Parameter is characterized but not tested.
DS39609A-page 316
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PIC18FXX20
TABLE 26-1: COMPARATOR SPECIFICATIONS
Operating Conditions: 3.0V < VDD < 5.5V, -40C < TA < +125C, unless otherwise stated Param No. D300 D301 D302 300 300A 301 Sym VIOFF VICM CMRR TRESP TMC2OV Characteristics Input Offset Voltage Input Common Mode Voltage Common Mode Rejection Ratio Response Time(1) Min -- 0 55 -- -- Typ 5.0 150 -- Max 10 VDD - 1.5 -- 400 600 10 Units mV V dB ns ns s PIC18FXX20 PIC18LFXX20 Comments
Comparator Mode Change to Output Valid
Note 1: Response time measured with one comparator input at (VDD - 1.5)/2, while the other input transitions from VSS to VDD.
TABLE 26-2:
VOLTAGE REFERENCE SPECIFICATIONS
Operating Conditions: 3.0V < VDD < 5.5V, -40C < TA < +125C, unless otherwise stated Param No. D310 D311 D312 310 Sym VRES VRAA VRUR TSET Characteristics Resolution Absolute Accuracy Unit Resistor Value (R) Settling Time(1) Min VDD/24 -- -- -- -- Typ -- -- -- 2k -- Max VDD/32 1/4 1/2 -- 10 Units LSb LSb LSb s Low Range (VRR = 1) High Range (VRR = 0) Comments
Note 1: Settling time measured while VRR = 1 and VR<3:0> transitions from 0000 to 1111.
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PIC18FXX20
FIGURE 26-5: LOW VOLTAGE DETECT CHARACTERISTICS
VDD (LVDIF can be cleared in software)
VLVD (LVDIF set by hardware)
LVDIF
TABLE 26-3:
LOW VOLTAGE DETECT CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended
Param Symbol No. D420
Characteristic LVV = 0000 LVD Voltage on VDD transition high LVV = 0001 to low LVV = 0010 LVV = 0011 LVV = 0100 LVV = 0101 LVV = 0110 LVV = 0111 LVV = 1000 LVV = 1001 LVV = 1010 LVV = 1011 LVV = 1100 LVV = 1101 LVV = 1110
Min 1.8 2.0 2.2 2.4 2.5 2.7 2.8 3.0 3.3 3.5 3.6 3.8 4.0 4.2 4.5 --
Typ 1.86 2.06 2.27 2.47 2.58 2.78 2.89 3.1 3.41 3.61 3.72 3.92 4.13 4.33 4.64 1.22
Max 1.91 2.12 2.34 2.55 2.66 2.86 2.98 3.2 3.52 3.72 3.84 4.04 4.26 4.46 4.78 --
Units V V V V V V V V V V V V V V V V
Conditions
D423
VBG
Bandgap Reference Voltage Value
Production tested at TAMB = 25C. Specifications over temp. limits ensured by characterization.
DS39609A-page 318
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PIC18FXX20
TABLE 26-4: MEMORY PROGRAMMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Characteristic Internal Program Memory Programming Specifications (Note 1) D110 D112 D113 VPP IPP IDDP Voltage on MCLR/VPP pin Current into MCLR/VPP pin Supply Current during Programming Data EEPROM Memory D120 D121 ED VDRW Cell Endurance Cell Endurance VDD for Read/Write 100K 10K VMIN
1M 100K -- -- --
DC Characteristics Param No.
Sym
Min
Typ
Max
Units
Conditions
9.00 -- --
-- -- --
13.25 5 10
V A mA
(Note 2)
E/W -40C to +85C E/W +85C to +125C V Using EECON to read/write VMIN = Minimum operating voltage
D120A ED
5.5
D122 D123
TDEW
Erase/Write Cycle Time
-- 40 100
4 -- -- 100K 10K
-- -- -- --
-- -- --
ms Year -40C to +85C (Note 3) Year 25C (Note 3) E/W -40C to +85C E/W +85C to +125C V V V V ms ms ms Year -40C to +85C (Note 3) Year 25C (Note 3) VMIN = Minimum operating voltage Using ICSP port Using ICSP port VMIN = Minimum operating voltage VDD > 4.5V VDD > 4.5V
TRETD Characteristic Retention Program FLASH Memory
D123A TRETD Characteristic Retention D130 D131 D132 EP VPR VIE Cell Endurance Cell Endurance VDD for Read VDD for Block Erase VDD for Externally Timed Erase or Write VDD for Self-timed Write ICSP Block Erase Cycle Time ICSP Erase or Write Cycle Time (externally timed) Self-timed Write Cycle Time
10K 1000 VMIN 4.5 4.5 VMIN
--
-- --
D130A EP
5.5 5.5 5.5 5.5
-- -- -- -- --
D132A VIW D132B VPEW D133 TIE
5
--
D133A TIW D133A TIW D134
1
-- 40 100
2.5 -- --
TRETD Characteristic Retention
D134A TRETD Characteristic Retention
Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: These specifications are for programming the on-chip program memory through the use of Table Write instructions. 2: The pin may be kept in this range at times other than programming, but it is not recommended. 3: Retention time is valid, provided no other specifications are violated.
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DS39609A-page 319
PIC18FXX20
26.4
26.4.1
AC (Timing) Characteristics
TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created following one of the following formats: 1. TppS2ppS 2. TppS T F Frequency Lowercase letters (pp) and their meanings: pp cc CCP1 ck CLKO cs CS di SDI do SDO dt Data in io I/O port mc MCLR Uppercase letters and their meanings: S F Fall H High I Invalid (Hi-impedance) L Low I2C only AA output access BUF Bus free TCC:ST (I2C specifications only) CC HD Hold ST DAT DATA input hold STA START condition 3. TCC:ST 4. Ts T (I2C specifications only) (I2C specifications only) Time
osc rd rw sc ss t0 t1 wr
OSC1 RD RD or WR SCK SS T0CKI T1CKI WR
P R V Z High Low
Period Rise Valid Hi-impedance High Low
SU STO
Setup STOP condition
DS39609A-page 320
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PIC18FXX20
26.4.2 TIMING CONDITIONS
The temperature and voltages specified in Table 26-5 apply to all timing specifications, unless otherwise noted. Figure 26-6 specifies the load conditions for the timing specifications.
TABLE 26-5:
TEMPERATURE AND VOLTAGE SPECIFICATIONS - AC
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Operating voltage VDD range as described in DC spec Section 26.1 and Section 26.3. LC parts operate for industrial temperatures only.
AC CHARACTERISTICS
FIGURE 26-6:
LOAD CONDITIONS FOR DEVICE TIMING SPECIFICATIONS
Load condition 1 VDD/2 RL Pin VSS Pin VSS CL RL = 464 CL = 50 pF for all pins except OSC2/CLKO and including D and E outputs as ports CL Load condition 2
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PIC18FXX20
26.4.3 TIMING DIAGRAMS AND SPECIFICATIONS EXTERNAL CLOCK TIMING (ALL MODES EXCEPT PLL)
Q4 Q1 Q2 Q3 Q4 Q1
FIGURE 26-7:
OSC1 1 2 CLKO 3 3 4 4
TABLE 26-6:
Param. No. 1A
EXTERNAL CLOCK TIMING REQUIREMENTS
Characteristic External CLKI Frequency(1) Oscillator Frequency(1) Min DC DC DC 0.1 4 4 4 5 Max 25 40 4 4 25 10 6.25 200 -- -- -- 10,000 250 250 160 -- -- -- -- -- 20 50 7.5 Units MHz MHz MHz MHz MHz MHz MHz kHz ns ns ns ns ns ns ns s ns ns s ns ns ns ns Conditions EC, ECIO, PIC18FX620/X720 EC, ECIO, PIC18FX520 RC osc XT osc HS osc HS + PLL osc, PIC18FX520 HS + PLL osc, PIC18FX620/X720 LP Osc mode EC, ECIO, PIC18FX620/X720 EC, ECIO, PIC18FX520 RC osc XT osc HS osc HS + PLL osc, PIC18FX520 HS + PLL osc, PIC18FX620/X720 LP osc TCY = 4/FOSC XT osc LP osc HS osc XT osc LP osc HS osc
Symbol FOSC
1
TOSC
External CLKI Period Oscillator Period(1)
(1)
25 160 250 250 25 100 100 25
2 3
TCY TosL, TosH
Instruction Cycle
Time(1)
100 30 2.5 10 -- -- --
External Clock in (OSC1) High or Low Time
4
TosR, TosF
External Clock in (OSC1) Rise or Fall Time
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time-base period for all configurations except PLL. All specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at "min." values with an external clock applied to the OSC1/CLKI pin. When an external clock input is used, the "max." cycle time limit is "DC" (no clock) for all devices.
TABLE 26-7:
Param. No. -- -- -- -- Sym FOSC FSYS trc CLK
PLL CLOCK TIMING SPECIFICATIONS (VDD = 4.2 TO 5.5V)
Characteristic Oscillator Frequency Range On-chip VCO System Frequency PLL Start-up Time (Lock Time) CLKO Stability (Jitter) Min 4 16 -- -2 Typ -- -- -- -- Max 10 40 2 +2 Units MHz MHz ms % HS mode HS mode Conditions
Data in "Typ" column is at 5V, 25C, unless otherwise stated. These parameters are for design guidance only and are not tested.
DS39609A-page 322
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PIC18FXX20
FIGURE 26-8: CLKO AND I/O TIMING
Q4 OSC1 10 CLKO 13 14 I/O Pin (Input) 17 I/O Pin (Output) Old Value 20, 21 Refer to Figure 26-6 for load conditions. New Value 15 19 18 12 16 11 Q1 Q2 Q3
Note:
TABLE 26-8:
Param. No. 10 11 12 13 14 15 16 17 18 18A 19 20 20A 21 21A 22 23 24 TINP TRBP TRCP TioF
CLKO AND I/O TIMING REQUIREMENTS
Characteristic OSC1 to CLKO OSC1 to CLKO CLKO rise time CLKO fall time CLKO to Port out valid Port in valid before CLKO Port in hold after CLKO OSC1 (Q1 cycle) to Port out valid OSC1 (Q2 cycle) to Port input invalid (I/O in hold time) Port input valid to OSC1 (I/O in setup time) Port output rise time Port output fall time INT pin high or low time RB7:RB4 change INT high or low time RC7:RC4 change INT high or low time PIC18FXX20 PIC18LFXX20 PIC18FXX20 PIC18LFXX20 PIC18FXX20 PIC18LFXX20 Min -- -- -- -- -- 0.25 TCY + 25 0 -- 100 200 0 -- -- -- -- TCY TCY 20 Typ 75 75 35 35 -- -- -- 50 -- -- -- 10 -- 10 -- -- -- Max 200 200 100 100 0.5 TCY + 20 -- -- 150 -- -- -- 25 60 25 60 -- -- Units ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns Conditions (1) (1) (1) (1) (1) (1) (1)
Symbol TosH2ckL TosH2ckH TckR TckF TckL2ioV TioV2ckH TckH2ioI TosH2ioV TosH2ioI
TioV2osH TioR
These parameters are asynchronous events not related to any internal clock edges. Note 1: Measurements are taken in RC mode, where CLKO output is 4 x TOSC.
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DS39609A-page 323
PIC18FXX20
FIGURE 26-9: PROGRAM MEMORY READ TIMING DIAGRAM
Q1 OSC1 A<19:16> BA0 AD<15:0>
Address Address Data from External Address
Q2
Q3
Q4
Q1
Q2
Address
150 151
160 155 166 167 168
163 162 161
ALE
164 169 171
CE
171A OE 165
Operating Conditions: 2.0V < VCC < 5.5V, -40C < TA < 125C unless otherwise stated.
TABLE 26-9:
Param. No 150 151 155 160 161 162 163 164 165 166 167 168 169 171 171A
CLKO AND I/O TIMING REQUIREMENTS
Characteristics Address out valid to ALE (address setup time) ALE to address out invalid (address hold time) ALE to OE Min 0.25 TCY - 10 5 10 0 0.125 TCY - 5 20 0 -- 0.5 TCY - 5 -- 0.75 TCY - 25 0.625 TCY - 10 0.25 TCY - 20 -- Typ -- -- 0.125 TCY -- -- -- -- TCY 0.5 TCY 0.25 TCY -- -- -- -- -- Max -- -- -- -- -- -- -- -- -- -- -- 0.5 TCY - 25 0.625 TCY + 10 -- 10 Units ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
Symbol TadV2alL TalL2adl TalL2oeL
TadZ2oeL AD high-Z to OE (bus release to OE) ToeH2adD OE to AD driven TadV2oeH LS Data valid before OE (data setup time) ToeH2adl OE to data in invalid (data hold time) TalH2alL TalH2alH Tacc Toe TalH2csL ALE pulse width ALE to ALE (cycle time) Address valid to data valid OE to data valid Chip Enable active to ALE ToeL2oeH OE pulse width
TalL2oeH ALE to OE TubL2oeH AD valid to Chip Enable active
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PIC18FXX20
FIGURE 26-10: PROGRAM MEMORY WRITE TIMING DIAGRAM
Q1 OSC1 A<19:16> BA0
Address Address
Q2
Q3
Q4
Q1
Q2
166 AD<15:0>
Address Data Address
150 151 ALE 171 CE 171A
153 156
154 WRH or WRL UB or LB 157 157A
Operating Conditions: 2.0V < VCC < 5.5V, -40C < TA < 125C unless otherwise stated.
TABLE 26-10: PROGRAM MEMORY WRITE TIMING REQUIREMENTS
Param. No 150 151 153 154 156 157 157A 166 171 171A Symbol Characteristics Min 0.25 TCY - 10 5 5 0.5 TCY - 5 0.5 TCY - 10 0.25 TCY 0.125 TCY - 5 -- 0.25 TCY - 20 -- Typ -- -- -- 0.5 TCY -- -- -- 0.25 TCY -- -- Max -- -- -- -- -- -- -- -- -- 10 Units ns ns ns ns ns ns ns ns ns ns
TadV2alL Address out valid to ALE (address setup time) TalL2adl TwrL ALE to address out invalid (address hold time) WRn pulse width TwrH2adl WRn to data out invalid (data hold time) TadV2wrH Data valid before WRn (data setup time) TbsV2wrL Byte select valid before WRn (byte select setup time) TwrH2bsI WRn to byte select invalid (byte select hold time) TalH2alH ALE to ALE (cycle time) TalH2csL Chip Enable active to ALE TubL2oeH AD valid to Chip Enable active
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PIC18FXX20
FIGURE 26-11: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP TIMER TIMING
VDD MCLR Internal POR PWRT Time-out OSC Time-out Internal RESET Watchdog Timer Reset 34 I/O Pins Note: Refer to Figure 26-6 for load conditions. 33 32 30
31
34
FIGURE 26-12:
VDD
BROWN-OUT RESET TIMING
BVDD 35 VBGAP = 1.2V
VIRVST Enable Internal Reference Voltage Internal Reference Voltage stable 36
TABLE 26-11: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER AND BROWN-OUT RESET REQUIREMENTS
Param. No. 30 31 32 33 34 35 36 37 Symbol TmcL TWDT TOST TPWRT TIOZ TBOR TIVRST TLVD Characteristic Min Typ -- 18 -- 72 2 -- 20 -- Max -- 33 1024 TOSC 132 -- -- 50 -- Units s ms -- ms s s s s VDD BVDD (see D005) TOSC = OSC1 period Conditions
2 MCLR Pulse Width (low) Watchdog Timer Time-out Period (No 7 Postscaler) Oscillation Start-up Timer Period 1024 TOSC Power up Timer Period 28 I/O high impedance from MCLR Low or Watchdog Timer Reset Brown-out Reset Pulse Width Time for Internal Reference Voltage to become stable Low Voltage Detect Pulse Width -- 200 -- 200
VDD VLVD
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PIC18FXX20
FIGURE 26-13:
T0CKI
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
40 42 T1OSO/T1CKI
41
45 47 TMR0 or TMR1 Note: Refer to Figure 26-6 for load conditions.
46
48
TABLE 26-12: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param. Symbol No. 40 41 42 Tt0H Tt0L Tt0P Characteristic T0CKI High Pulse Width T0CKI Low Pulse Width T0CKI Period No Prescaler With Prescaler No Prescaler With Prescaler No Prescaler With Prescaler Min 0.5 TCY + 20 10 0.5 TCY + 20 10 TCY + 10 Greater of: 20 nS or TCY + 40 N 0.5 TCY + 20 10 25 30 50 0.5 TCY + 5 10 25 30 TBD Greater of: 20 nS or TCY + 40 N 60 DC 2 TOSC Max -- -- -- -- -- -- Units ns ns ns ns ns ns N = prescale value (1, 2, 4,..., 256) Conditions
45
Tt1H
T1CKI Synchronous, no prescaler High Time Synchronous, PIC18FXX20 with prescaler PIC18LFXX20 Asynchronous PIC18FXX20 PIC18LFXX20
-- -- -- -- -- -- -- -- -- TBD --
ns ns ns ns ns ns ns ns ns ns ns N = prescale value (1, 2, 4, 8)
46
Tt1L
T1CKI Low Synchronous, no prescaler Time Synchronous, PIC18FXX20 with prescaler PIC18LFXX20 Asynchronous PIC18FXX20 PIC18LFXX20
47
Tt1P
T1CKI Input Period
Synchronous
Asynchronous Ft1 48 T1CKI Oscillator Input Frequency Range Tcke2tmrI Delay from External T1CKI Clock Edge to Timer Increment
-- 50 7 TOSC
ns kHz --
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PIC18FXX20
FIGURE 26-14: CAPTURE/COMPARE/PWM TIMINGS (ALL CCP MODULES)
CCPx (Capture Mode)
50 52
51
CCPx (Compare or PWM Mode) 53 Note: Refer to Figure 26-6 for load conditions. 54
TABLE 26-13: CAPTURE/COMPARE/PWM REQUIREMENTS (ALL CCP MODULES)
Param. Symbol No. 50 TccL Characteristic CCPx Input Low No Prescaler Time With PIC18FXX20 Prescaler PIC18LFXX20 CCPx Input High Time No Prescaler With Prescaler PIC18FXX20 PIC18LFXX20 Min 0.5 TCY + 20 10 20 0.5 TCY + 20 10 20 3 TCY + 40 N PIC18FXX20 PIC18LFXX20 54 TccF CCPx Output Fall Time PIC18FXX20 PIC18LFXX20 -- -- -- -- Max -- -- -- -- -- -- -- 25 45 25 45 Units ns ns ns ns ns ns ns ns ns ns ns N = prescale value (1,4 or 16) Conditions
51
TccH
52 53
TccP TccR
CCPx Input Period CCPx Output Rise Time
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FIGURE 26-15:
RE2/CS
PARALLEL SLAVE PORT TIMING (PIC18F8X20)
RE0/RD
RE1/WR
65 RD7:RD0 62 63 Note: Refer to Figure 26-6 for load conditions.
64
TABLE 26-14: PARALLEL SLAVE PORT REQUIREMENTS (PIC18F8X20)
Param. No. 62 63 64 65 66 Symbol TdtV2wrH TwrH2dtI TrdL2dtV TrdH2dtI TibfINH Characteristic Data in valid before WR or CS (setup time) WR or CS to data-in invalid (hold time) PIC18FXX20 PIC18LFXX20 Min 20 25 20 35 -- -- 10 -- Max -- -- -- -- 80 90 30 3 TCY Units ns ns ns ns ns ns ns Extended Temp. range Conditions
Extended Temp. range
RD and CS to data-out valid RD or CS to data-out invalid Inhibit of the IBF flag bit being cleared from WR or CS
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PIC18FXX20
FIGURE 26-16:
SS 70 SCK (CKP = 0) 71 72 78 79
EXAMPLE SPI MASTER MODE TIMING (CKE = 0)
SCK (CKP = 1) 79 MSb 75, 76 SDI MSb In 74 73 Note: Refer to Figure 26-6 for load conditions. bit6 - - - -1 LSb In bit6 - - - - - -1 78 LSb
80 SDO
TABLE 26-15: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 0)
Param. No. 70 71 71A 72 72A 73 73A 74 75 76 78 79 80 TdiV2scH, TdiV2scL TB2B TscH2diL, TscL2diL TdoR TdoF TscR TscF TscH2doV, TscL2doV TscL Symbol TssL2scH, TssL2scL TscH Characteristic SS to SCK or SCK input SCK input high time (Slave mode) SCK input low time (Slave mode) Continuous Single Byte Continuous Single Byte Min TCY 1.25 TCY + 30 40 1.25 TCY + 30 40 100 1.5 TCY + 40 100 -- -- -- PIC18FXX20 PIC18LFXX20 PIC18FXX20 PIC18LFXX20 -- -- -- -- -- Max Units -- -- -- -- -- -- -- -- 25 45 25 25 45 25 50 100 ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns (Note 2) (Note 1) (Note 1) Conditions
Setup time of SDI data input to SCK edge Last clock edge of Byte1 to the 1st clock edge of Byte2 Hold time of SDI data input to SCK edge SDO data output rise time SDO data output fall time SCK output rise time (Master mode) SDO data output valid after SCK edge PIC18FXX20 PIC18LFXX20
SCK output fall time (Master mode)
Note 1: Requires the use of Parameter #73A. 2: Only if Parameter #71A and #72A are used.
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FIGURE 26-17:
SS 81 SCK (CKP = 0) 71 73 SCK (CKP = 1) 80 78 MSb 75, 76 SDI MSb In 74 Note: Refer to Figure 26-6 for load conditions. bit6 - - - -1 LSb In bit6 - - - - - -1 LSb 72 79
EXAMPLE SPI MASTER MODE TIMING (CKE = 1)
SDO
TABLE 26-16: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 1)
Param. No. 71 71A 72 72A 73 73A 74 75 76 78 79 80 81 TdiV2scH, TdiV2scL TB2B TscH2diL, TscL2diL TdoR TdoF TscR TscF TscH2doV, TscL2doV TscL Symbol TscH Characteristic SCK input high time (Slave mode) SCK input low time (Slave mode) Continuous Single Byte Continuous Single Byte Min 1.25 TCY + 30 40 1.25 TCY + 30 40 100 1.5 TCY + 40 100 -- -- PIC18FXX20 PIC18LFXX20 -- -- PIC18FXX20 PIC18LFXX20 TCY -- Max Units -- -- -- -- -- -- -- 25 45 25 25 45 25 50 100 -- ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns (Note 2) (Note 1) (Note 1) Conditions
Setup time of SDI data input to SCK edge Last clock edge of Byte1 to the 1st clock edge of Byte2 Hold time of SDI data input to SCK edge SDO data output rise time SDO data output fall time SCK output rise time (Master mode) SDO data output valid after SCK edge PIC18FXX20 PIC18LFXX20
SCK output fall time (Master mode)
TdoV2scH, SDO data output setup to SCK edge TdoV2scL
Note 1: Requires the use of Parameter #73A. 2: Only if Parameter #71A and #72A are used.
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PIC18FXX20
FIGURE 26-18:
SS 70 SCK (CKP = 0) 71 72 78 79 83
EXAMPLE SPI SLAVE MODE TIMING (CKE = 0)
SCK (CKP = 1) 79 MSb 75, 76 SDI 73 Note: Refer to Figure 26-6 for load conditions. MSb In 74 bit6 - - - -1 LSb In bit6 - - - - - -1 78 LSb 77
80 SDO
TABLE 26-17: EXAMPLE SPI MODE REQUIREMENTS (SLAVE MODE TIMING, CKE = 0)
Param. No. 70 71 71A 72 72A 73 73A 74 75 76 77 78 79 80 83 Symbol Characteristic Min TCY Max Units Conditions -- ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
Continuous 1.25 TCY + 30 -- Single Byte 40 -- TscL SCK input low time Continuous 1.25 TCY + 30 -- (Slave mode) Single Byte 40 -- TdiV2scH, Setup time of SDI data input to SCK edge 100 -- TdiV2scL Last clock edge of Byte1 to the first clock edge of Byte2 1.5 TCY + 40 -- TB2B TscH2diL, Hold time of SDI data input to SCK edge 100 -- TscL2diL TdoR SDO data output rise time PIC18FXX20 -- 25 PIC18LFXX20 45 TdoF SDO data output fall time -- 25 TssH2doZ SS to SDO output hi-impedance 10 50 TscR SCK output rise time (Master mode) PIC18FXX20 -- 25 PIC18LFXX20 45 TscF SCK output fall time (Master mode) -- 25 TscH2doV, SDO data output valid after SCK edge PIC18FXX20 -- 50 TscL2doV PIC18LFXX20 100 1.5 TCY + 40 --
TssL2scH, SS to SCK or SCK input TssL2scL TscH SCK input high time (Slave mode)
(Note 1) (Note 1)
(Note 2)
TscH2ssH, SS after SCK edge TscL2ssH Note 1: Requires the use of Parameter #73A. 2: Only if Parameter #71A and #72A are used.
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FIGURE 26-19:
SS 70 83 71 72
EXAMPLE SPI SLAVE MODE TIMING (CKE = 1)
82
SCK (CKP = 0)
SCK (CKP = 1) 80
SDO
MSb 75, 76
bit6 - - - - - -1
LSb 77
SDI
MSb In
bit6 - - - -1
LSb In
Note:
74 Refer to Figure 26-6 for load conditions.
TABLE 26-18: EXAMPLE SPI SLAVE MODE REQUIREMENTS (CKE = 1)
Param. No. 70 71 71A 72 72A 73A 74 75 76 77 78 79 80 82 83 Symbol TssL2scH, TssL2scL TscH TscL TB2B TscH2diL, TscL2diL TdoR TdoF TssH2doZ TscR Characteristic SS to SCK or SCK input SCK input high time (Slave mode) Min TCY Max Units Conditions -- -- -- -- -- -- -- 25 45 25 50 25 45 25 50 100 50 100 -- ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
Continuous 1.25 TCY + 30 Single Byte 40 SCK input low time Continuous 1.25 TCY + 30 (Slave mode) Single Byte 40 Last clock edge of Byte1 to the first clock edge of Byte2 1.5 TCY + 40 Hold time of SDI data input to SCK edge 100 SDO data output rise time SDO data output fall time PIC18FXX20 PIC18LFXX20 -- -- 10 -- -- -- -- -- -- -- 1.5 TCY + 40
(Note 1) (Note 1) (Note 2)
SS to SDO output hi-impedance SCK output rise time PIC18FXX20 (Master mode) PIC18LFXX20
TscF SCK output fall time (Master mode) TscH2doV, SDO data output valid after SCK PIC18FXX20 TscL2doV edge PIC18LFXX20 TssL2doV SDO data output valid after SS PIC18FXX20 edge PIC18LFXX20
TscH2ssH, SS after SCK edge TscL2ssH Note 1: Requires the use of Parameter #73A. 2: Only if Parameter #71A and #72A are used.
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PIC18FXX20
FIGURE 26-20: I2C BUS START/STOP BITS TIMING
SCL 90 SDA
91 92
93
START Condition
STOP Condition
Note:
Refer to Figure 26-6 for load conditions.
TABLE 26-19: I2C BUS START/STOP BITS REQUIREMENTS (SLAVE MODE)
Param. Symbol No. 90 91 92 93 TSU:STA Characteristic 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode Min 4700 600 4000 600 4700 600 4000 600 Max -- -- -- -- -- -- -- -- Units ns ns ns ns Conditions Only relevant for Repeated START condition After this period, the first clock pulse is generated
START condition Setup time THD:STA START condition Hold time TSU:STO STOP condition Setup time THD:STO STOP condition Hold time
FIGURE 26-21:
I2C BUS DATA TIMING
103 100 101 102
SCL
90 91
106
107 92
SDA In
110 109 109
SDA Out Note: Refer to Figure 26-6 for load conditions.
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TABLE 26-20: I2C BUS DATA REQUIREMENTS (SLAVE MODE)
Param. No. 100 Symbol THIGH Characteristic Clock high time 100 kHz mode 400 kHz mode SSP Module 101 TLOW Clock low time 100 kHz mode 400 kHz mode SSP Module 102 TR SDA and SCL rise time SDA and SCL fall time START condition setup time START condition hold time Data input hold time Data input setup time STOP condition setup time Output valid from clock Bus free time 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode D102 CB Bus capacitive loading Min 4.0 0.6 1.5 TCY 4.7 1.3 1.5 TCY -- 20 + 0.1 CB -- 20 + 0.1 CB 4.7 0.6 4.0 0.6 0 0 250 100 4.7 0.6 -- -- 4.7 1.3 -- Max -- -- -- -- -- -- 1000 300 300 300 -- -- -- -- -- 0.9 -- -- -- -- 3500 -- -- -- 400 ns ns ns ns s s s s ns s ns ns s s ns ns s s pF Time the bus must be free before a new transmission can start (Note 1) (Note 2) CB is specified to be from 10 to 400 pF Only relevant for Repeated START condition After this period, the first clock pulse is generated CB is specified to be from 10 to 400 pF s s PIC18FXX20 must operate at a minimum of 1.5 MHz PIC18FXX20 must operate at a minimum of 10 MHz Units s s Conditions PIC18FXX20 must operate at a minimum of 1.5 MHz PIC18FXX20 must operate at a minimum of 10 MHz
103
TF
90 91 106 107 92 109 110
TSU:STA THD:STA THD:DAT TSU:DAT TSU:STO TAA TBUF
Note 1: As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (min. 300 ns) of the falling edge of SCL to avoid unintended generation of START or STOP conditions. 2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but the requirement TSU:DAT 250 ns must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line. TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the Standard mode I2C bus specification) before the SCL line is released.
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PIC18FXX20
FIGURE 26-22: MASTER SSP I2C BUS START/STOP BITS TIMING WAVEFORMS
SCL 90 SDA
91 92
93
START Condition Note: Refer to Figure 26-6 for load conditions.
STOP Condition
TABLE 26-21: MASTER SSP I2C BUS START/STOP BITS REQUIREMENTS
Param. Symbol No. 90 TSU:STA Characteristic START condition Setup time 91 THD:STA START condition Hold time 92 TSU:STO STOP condition Setup time 93 THD:STO STOP condition Hold time 100 kHz mode 400 kHz mode 1 MHz mode
(1)
Min 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) pins.
Max -- -- -- -- -- -- -- -- -- -- -- --
Units ns
Conditions Only relevant for Repeated START condition After this period, the first clock pulse is generated
100 kHz mode 400 kHz mode 1 MHz mode
(1)
ns
100 kHz mode 400 kHz mode 1 MHz mode(1) 100 kHz mode 400 kHz mode 1 MHz mode(1)
2C
ns
ns
Note 1: Maximum pin capacitance = 10 pF for all I
FIGURE 26-23:
MASTER SSP I2C BUS DATA TIMING
103 100 101 102
SCL SDA In
90
91
106
107
92
109
109
110
SDA Out Note: Refer to Figure 26-6 for load conditions.
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TABLE 26-22: MASTER SSP I2C BUS DATA REQUIREMENTS
Param. Symbol No. 100 THIGH Characteristic Clock high time 100 kHz mode 400 kHz mode 1 MHz mode(1) 101 TLOW Clock low time 100 kHz mode 400 kHz mode 1 MHz mode 102 TR SDA and SCL rise time SDA and SCL fall time
(1)
Min 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) -- 20 + 0.1 CB -- -- 20 + 0.1 CB -- 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 0 0 TBD 250 100 TBD 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) 2(TOSC)(BRG + 1) -- -- -- 4.7 1.3 TBD -- I2C
Max -- -- -- -- -- -- 1000 300 300 300 300 100 -- -- -- -- -- -- -- 0.9 -- -- -- -- -- -- -- 3500 1000 -- -- -- -- 400
Units ms ms ms ms ms ms ns ns ns ns ns ns ms ms ms ms ms ms ns ms ns ns ns ns ms ms ms ns ns ns ms ms ms pF
Conditions
100 kHz mode 400 kHz mode 1 MHz mode(1) 100 kHz mode 400 kHz mode 1 MHz mode
(1)
CB is specified to be from 10 to 400 pF CB is specified to be from 10 to 400 pF Only relevant for Repeated START condition After this period, the first clock pulse is generated
103
TF
90
TSU:STA
START condition 100 kHz mode setup time 400 kHz mode 1 MHz mode(1)
91
THD:STA START condition 100 kHz mode hold time 400 kHz mode 1 MHz mode(1) THD:DAT Data input hold time TSU:DAT Data input setup time 100 kHz mode 400 kHz mode 1 MHz mode(1) 100 kHz mode 400 kHz mode 1 MHz mode(1) 100 kHz mode 400 kHz mode 1 MHz mode(1)
106
107
(Note 2)
92
TSU:STO STOP condition setup time TAA
109
Output valid from 100 kHz mode clock 400 kHz mode 1 MHz mode(1) Bus free time 100 kHz mode 400 kHz mode 1 MHz mode(1)
110
TBUF
Time the bus must be free before a new transmission can start
D102
CB
Bus capacitive loading
Note 1: Maximum pin capacitance = 10 pF for all pins. 2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but parameter #107 250 ns must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line, parameter #102 + parameter #107 = 1000 + 250 = 1250 ns (for 100 kHz mode) before the SCL line is released.
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PIC18FXX20
FIGURE 26-24: USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RC6/TX1/CK1 pin RC7/RX1/DT1 pin 120 Note:
121
121
122
Refer to Figure 26-6 for load conditions.
TABLE 26-23: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Param. Symbol No. 120 Characteristic PIC18FXX20 PIC18LFXX20 PIC18FXX20 PIC18LFXX20 PIC18FXX20 PIC18LFXX20 Min -- -- -- -- -- -- Max 40 100 20 50 20 50 Units ns ns ns ns ns ns Conditions
TckH2dtV SYNC XMIT (MASTER & SLAVE) Clock high to data out valid Tckrf Tdtrf Clock out rise time and fall time (Master mode) Data out rise time and fall time
121 122
FIGURE 26-25:
RC6/TX1/CK1 pin RC7/RX1/DT1 pin
USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
125
126 Note: Refer to Figure 26-6 for load conditions.
TABLE 26-24: USART SYNCHRONOUS RECEIVE REQUIREMENTS
Param. No. 125 126 Symbol TdtV2ckl TckL2dtl Characteristic SYNC RCV (MASTER & SLAVE) Data hold before CK (DT hold time) Data hold after CK (DT hold time) Min 10 15 Max -- -- Units ns ns Conditions
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TABLE 26-25: A/D CONVERTER CHARACTERISTICS: PIC18FXX20 (INDUSTRIAL, EXTENDED) PIC18LFXX20 (INDUSTRIAL)
Param Symbol No. A01 A03 A04 A05 A06 A10 A20 A20A A21 A22 A25 A30 A40 VREFH VREFL VAIN ZAIN IAD NR EIL EDL EFS EOFF -- VREF Characteristic Resolution Integral linearity error Differential linearity error Full scale error Offset error Monotonicity Reference voltage (VREFH - VREFL) Reference voltage High Reference voltage Low Analog input voltage Recommended impedance of analog voltage source A/D conversion PIC18FXX20 current (VDD) PIC18LFXX20 VREF input current (Note 2) 0V 3V AVss AVss - 0.3V AVSS - 0.3V -- -- -- 10 Min -- -- -- -- -- -- -- -- -- -- Typ -- -- -- -- -- -- -- -- -- -- guaranteed(3) -- -- -- -- -- -- 180 90 -- -- -- AVDD + 0.3V AVDD VREF + 0.3V 10.0 -- -- 1000 Max 10 TBD <1 TBD <1 TBD <1 TBD <1 TBD Units bit bit Conditions VREF = VDD 3.0V VREF = VDD < 3.0V
LSb VREF = VDD 3.0V LSb VREF = VDD < 3.0V LSb VREF = VDD 3.0V LSb VREF = VDD < 3.0V LSb VREF = VDD 3.0V LSb VREF = VDD < 3.0V LSb VREF = VDD 3.0V LSb VREF = VDD < 3.0V -- V V V V V k A A A Average current consumption when A/D is on (Note 1) During VAIN acquisition. Based on differential of VHOLD to VAIN. To charge CHOLD see Section 19.0. During A/D conversion cycle. For 10-bit resolution VSS VAIN VREF
A50
IREF
--
--
10
A
Note 1: When A/D is off, it will not consume any current other than minor leakage current. The power-down current spec includes any such leakage from the A/D module. VREF current is from RA2/AN2/VREF- and RA3/AN3/VREF+ pins or AVDD and AVSS pins, whichever is selected as reference input. 2: Vss VAIN VREF 3: The A/D conversion result never decreases with an increase in the input voltage, and has no missing codes.
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PIC18FXX20
FIGURE 26-26: A/D CONVERSION TIMING
BSF ADCON0, GO (Note 2) Q4 A/D CLK 132 131 130
A/D DATA
9
8
7
...
...
2
1
0
ADRES ADIF GO
OLD_DATA
NEW_DATA TCY DONE
SAMPLE
SAMPLING STOPPED
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. 2: This is a minimal RC delay (typically 100 ns), which also disconnects the holding capacitor from the analog input.
TABLE 26-26: A/D CONVERSION REQUIREMENTS
Param. Symbol No. 130 TAD Characteristic A/D clock period PIC18FXX20 PIC18LFXX20 PIC18FXX20 PIC18LFXX20 131 132 135 136 TCNV TACQ TSWC TAMP Conversion time (not including acquisition time) (Note 1) Acquisition time (Note 3) Switching time from convert sample Amplifier settling time (Note 2) Min 1.6 3.0 2.0 3.0 11 15 10 -- 1 Max 20(5) 20(5) 6.0 9.0 12 -- -- (Note 4) -- s This may be used if the "new" input voltage has not changed by more than 1 LSb (i.e., 5 mV @ 5.12V) from the last sampled voltage (as stated on CHOLD). Units s s s s TAD s s -40C Temp 125C 0C Temp 125C Conditions TOSC based, VREF 3.0V TOSC based, VREF full range A/D RC mode A/D RC mode
Note 1: ADRES register may be read on the following TCY cycle. 2: See Section 19.0 for minimum conditions, when input voltage has changed more than 1 LSb. 3: The time for the holding capacitor to acquire the "New" input voltage, when the voltage changes full scale after the conversion (AVDD to AVSS, or AVSS to AVDD). The source impedance (RS) on the input channels is 50. 4: On the next Q4 cycle of the device clock. 5: The time of the A/D clock period is dependent on the device frequency and the TAD clock divider.
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27.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES
Graphs and Tables are not available at this time.
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NOTES:
DS39609A-page 342
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28.0
28.1
PACKAGING INFORMATION
Package Marking Information
64-Lead TQFP
Example
XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX YYWWNNN
PIC18F6620 -I/PT 0243017
80-Lead TQFP
Example
XXXXXXXXXXXX XXXXXXXXXXXX YYWWNNN
PIC18F8720 -E/PT 0243017
Legend: XX...X Y YY WW NNN
Customer specific information* Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week `01') Alphanumeric traceability code
Note:
In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line thus limiting the number of available characters for customer specific information.
*
Standard PICmicro device marking consists of Microchip part number, year code, week code, and traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP price.
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PIC18FXX20
28.2 Package Details
The following sections give the technical details of the packages.
64-Lead Plastic Thin Quad Flatpack (PT) 10x10x1 mm Body, 1.0/0.10 mm Lead Form (TQFP)
E E1 #leads=n1 p
D1
D
2 1 B n CH x 45 A c A2 L
A1 (F)
Number of Pins Pitch Pins per Side Overall Height Molded Package Thickness Standoff Foot Length Footprint (Reference) Foot Angle Overall Width Overall Length Molded Package Width Molded Package Length Lead Thickness Lead Width Pin 1 Corner Chamfer Mold Draft Angle Top Mold Draft Angle Bottom * Controlling Parameter Significant Characteristic
Units Dimension Limits n p n1 A A2 A1 L (F) E D E1 D1 c B CH
MIN
.039 .037 .002 .018 0 .463 .463 .390 .390 .005 .007 .025 5 5
INCHES NOM 64 .020 16 .043 .039 .006 .024 .039 3.5 .472 .472 .394 .394 .007 .009 .035 10 10
MAX
MIN
.047 .041 .010 .030 7 .482 .482 .398 .398 .009 .011 .045 15 15
MILLIMETERS* NOM 64 0.50 16 1.00 1.10 0.95 1.00 0.05 0.15 0.45 0.60 1.00 0 3.5 11.75 12.00 11.75 12.00 9.90 10.00 9.90 10.00 0.13 0.18 0.17 0.22 0.64 0.89 5 10 5 10
MAX
1.20 1.05 0.25 0.75 7 12.25 12.25 10.10 10.10 0.23 0.27 1.14 15 15
Notes: Dimensions D1 and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" (0.254mm) per side. JEDEC Equivalent: MS-026 Drawing No. C04-085
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80-Lead Plastic Thin Quad Flatpack (PT) 12x12x1 mm Body, 1.0/0.10 mm Lead Form (TQFP)
E E1 #leads=n1 p
D1
D
B n
2 1
CH x 45 A
c
L A1 (F) Units Dimension Limits n p n1 A A2 A1 L (F) E D E1 D1 c B CH INCHES NOM 80 .020 20 .043 .039 .004 .024 .039 3.5 .551 .551 .472 .472 .006 .009 .035 10 10 MILLIMETERS* NOM 80 0.50 20 1.00 1.10 0.95 1.00 0.05 0.10 0.45 0.60 1.00 0 3.5 13.75 14.00 13.75 14.00 11.75 12.00 11.75 12.00 0.09 0.15 0.17 0.22 0.64 0.89 5 10 5 10
A2
MIN
MAX
MIN
MAX
Number of Pins Pitch Pins per Side Overall Height Molded Package Thickness Standoff Foot Length Footprint (Reference) Foot Angle Overall Width Overall Length Molded Package Width Molded Package Length Lead Thickness Lead Width Pin 1 Corner Chamfer Mold Draft Angle Top Mold Draft Angle Bottom * Controlling Parameter Significant Characteristic
.039 .037 .002 .018 0 .541 .541 .463 .463 .004 .007 .025 5 5
.047 .041 .006 .030 7 .561 .561 .482 .482 .008 .011 .045 15 15
1.20 1.05 0.15 0.75 7 14.25 14.25 12.25 12.25 0.20 0.27 1.14 15 15
Notes: Dimensions D1 and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" (0.254mm) per side. JEDEC Equivalent: MS-026 Drawing No. C04-092
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PIC18FXX20
NOTES:
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PIC18FXX20
APPENDIX A: REVISION HISTORY APPENDIX B:
Revision A (January 2003)
Original data sheet for the PIC18FXX20 family which includes PIC18F6520, PIC18F6620, PIC18F6720, PIC18F8520, PIC18F8620 and PIC18F8720 devices. This data sheet is based on the previous PIC18FXX20 Data Sheet (DS39580).
DEVICE DIFFERENCES
The differences between the devices listed in this data sheet are shown in Table B-1.
TABLE B-1:
DEVICE DIFFERENCES
PIC18F6520 32 2048 2048 Yes PIC18F6620 PIC18F6720 64 3840 512 No 128 3840 512 No PIC18F8520 PIC18F8620 32 2048 2048 Yes 64 3840 512 No PIC18F8720 128 3840 512 No Ports A, B, C, D, E, F, G, H, J 16 Yes
Feature On-chip Program Memory (Kbytes) Data Memory (bytes) Boot Block (bytes) Timer1 Low Power Option I/O Ports
Ports A, B, Ports A, B, Ports A, B, Ports A, B, Ports A, B, C, D, E, F, G C, D, E, F, G C, D, E, F, G C, D, E, F, G, C, D, E, F, G, H, J H, J 12 No 12 No 12 No 16 Yes 16 Yes
A/D Channels External Memory Interface Package Types
64-pin TQFP 64-pin TQFP 64-pin TQFP 80-pin TQFP 80-pin TQFP 80-pin TQFP
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APPENDIX C: CONVERSION CONSIDERATIONS APPENDIX D: MIGRATION FROM MID-RANGE TO ENHANCED DEVICES
This appendix discusses the considerations for converting from previous versions of a device to the ones listed in this data sheet. Typically, these changes are due to the differences in the process technology used. An example of this type of conversion is from a PIC17C756 to a PIC18F8720. TBD
A detailed discussion of the differences between the mid-range MCU devices (i.e., PIC16CXXX) and the enhanced devices (i.e., PIC18FXXX) is provided in AN716, "Migrating Designs from PIC16C74A/74B to PIC18C442." The changes discussed, while device specific, are generally applicable to all mid-range to enhanced device migrations. This Application Note is available as Literature Number DS00716.
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APPENDIX E: MIGRATION FROM HIGH-END TO ENHANCED DEVICES
A detailed discussion of the migration pathway and differences between the high-end MCU devices (i.e., PIC17CXXX) and the enhanced devices (i.e., PIC18FXXXX) is provided in AN726, "PIC17CXXX to PIC18CXXX Migration." This Application Note is available as Literature Number DS00726.
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NOTES:
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INDEX
A
A/D ................................................................................... 213 A/D Converter Interrupt, Configuring ....................... 217 Acquisition Requirements ........................................ 218 Acquisition Time ....................................................... 218 ADCON0 Register .................................................... 213 ADCON1 Register .................................................... 213 ADCON2 Register .................................................... 213 ADRESH Register ............................................ 213, 216 ADRESL Register ............................................ 213, 216 Analog Port Pins ...................................................... 128 Analog Port Pins, Configuring .................................. 219 Associated Register Summary ................................. 221 Calculating Minimum Required Acquisition Time (Example) ............................. 218 CCP2 Trigger ........................................................... 220 Configuring the Module ............................................ 217 Conversion Clock (TAD) ........................................... 219 Conversion Requirements ....................................... 340 Conversion Status (GO/DONE Bit) .......................... 216 Conversion Tad Cycles ............................................ 220 Conversions ............................................................. 220 Converter Characteristics ........................................ 339 Equations ................................................................. 218 Minimum Charging Time .......................................... 218 Special Event Trigger (CCP) .................................... 152 Special Event Trigger (CCP2) .................................. 220 TAD vs. Device Operating Frequencies (Table) ....... 219 Absolute Maximum Ratings ............................................. 307 AC (Timing) Characteristics ............................................. 320 Load Conditions for Device Timing Specifications ................................................... 321 Parameter Symbology ............................................. 320 Temperature and Voltage Specifications ................. 321 Timing Conditions .................................................... 321 ACKSTAT Status Flag ..................................................... 187 ADCON0 Register ............................................................ 213 GO/DONE Bit ........................................................... 216 ADCON1 Register ............................................................ 213 ADCON2 Register ............................................................ 213 ADDLW ............................................................................ 265 Addressable Universal Synchronous Asynchronous Receiver Transmitter (USART) ................................ 197 ADDWF ............................................................................ 265 ADDWFC ......................................................................... 266 ADRESH Register .................................................... 213, 216 ADRESL Register .................................................... 213, 216 Analog-to-Digital Converter. See A/D ANDLW ............................................................................ 266 ANDWF ............................................................................ 267 Assembler MPASM Assembler .................................................. 301 Block Diagrams 16-bit Byte Select Mode ............................................. 75 16-bit Byte Write Mode .............................................. 73 16-bit Word Write Mode ............................................. 74 A/D ........................................................................... 216 Analog Input Model .................................................. 217 Baud Rate Generator .............................................. 183 Capture Mode Operation ......................................... 151 Comparator Analog Input Model .............................. 227 Comparator I/O Operating Modes (Diagram) .......... 224 Comparator Output .................................................. 226 Comparator Voltage Reference ............................... 230 Compare Mode Operation ....................................... 152 Low Voltage Detect (LVD) ....................................... 234 Low Voltage Detect (LVD) with External Input ......... 234 MSSP (I2C Master Mode) ........................................ 181 MSSP (I2C Mode) .................................................... 166 MSSP (SPI Mode) ................................................... 157 On-Chip Reset Circuit ................................................ 29 PIC18F6X20 Architecture ............................................ 9 PIC18F8X20 Architecture .......................................... 10 PLL ............................................................................ 23 PORT/LAT/TRIS Operation ..................................... 103 PORTA RA3:RA0 and RA5 Pins ................................... 104 RA4/T0CKI Pin ................................................ 104 RA6 Pin (as I/O) .............................................. 104 PORTB RB2:RB0 Pins .................................................. 107 RB3 Pin ........................................................... 107 RB7:RB4 Pins .................................................. 106 PORTC (Peripheral Output Override) ...................... 109 PORTD and PORTE Parallel Slave Port ........................................... 128 PORTD in I/O Port Mode ......................................... 111 PORTD in System Bus Mode .................................. 112 PORTE in I/O Mode ................................................. 115 PORTE in System Bus Mode .................................. 115 PORTF RF1/AN6/C2OUT and RF2/AN5/C1OUT Pins ............................. 117 RF6/RF3 and RF0 Pins ................................... 118 RF7 Pin ............................................................ 118 PORTG (Peripheral Output Override) ...................... 120 PORTH RH3:RH0 Pins in System Bus Mode ............... 123 RH3:RH0 Pins in I/O Mode .............................. 122 RH7:RH4 Pins in I/O Mode .............................. 122 PORTJ RJ4:RJ0 Pins in System Bus Mode ................. 126 RJ7:RJ6 Pins in System Bus Mode ................. 126 PORTJ in I/O Mode ................................................. 125 PWM Operation (Simplified) .................................... 154 Reads from FLASH Program Memory ....................... 65 Single Comparator ................................................... 225 Table Read Operation ............................................... 61 Table Write Operation ................................................ 62 Table Writes to FLASH Program Memory ................. 67 Timer0 in 16-bit Mode .............................................. 132 Timer0 in 8-bit Mode ................................................ 132
B
Baud Rate Generator ....................................................... 183 BC .................................................................................... 267 BCF .................................................................................. 268 BF Status Flag ................................................................. 187
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Timer1 ...................................................................... 136 Timer1 (16-bit R/W Mode) ........................................ 136 Timer2 ...................................................................... 142 Timer3 ...................................................................... 144 Timer3 in 16-bit R/W Mode ...................................... 144 Timer4 ...................................................................... 148 USART Receive ....................................................... 206 USART Transmit ...................................................... 204 Voltage Reference Output Buffer Example .............. 231 Watchdog Timer ....................................................... 251 BN .................................................................................... 268 BNC .................................................................................. 269 BNN .................................................................................. 269 BNOV ............................................................................... 270 BNZ .................................................................................. 270 BOR. See Brown-out Reset BOV .................................................................................. 273 BRA .................................................................................. 271 BRG. See Baud Rate Generator Brown-out Reset (BOR) ............................................. 30, 239 BSF .................................................................................. 271 BTFSC ............................................................................. 272 BTFSS .............................................................................. 272 BTG .................................................................................. 273 BZ ..................................................................................... 274 Initializing PORTA .................................................... 103 Initializing PORTB .................................................... 106 Initializing PORTC ................................................... 109 Initializing PORTD ................................................... 111 Initializing PORTE .................................................... 114 Initializing PORTF .................................................... 117 Initializing PORTG ................................................... 120 Initializing PORTH ................................................... 122 Initializing PORTJ .................................................... 125 Loading the SSPBUF (SSPSR) Register ................. 160 Reading a FLASH Program Memory Word ............... 65 Saving STATUS, WREG and BSR Registers in RAM ............................................................. 102 Writing to FLASH Program Memory .....................69-70 Code Protection ............................................................... 239 COMF .............................................................................. 276 Comparator Analog Input Connection Considerations ................ 227 Associated Registers ............................................... 228 Configuration ........................................................... 224 Effects of RESET ..................................................... 227 Interrupts .................................................................. 226 Operation ................................................................. 225 Operation During SLEEP ......................................... 227 Outputs .................................................................... 225 Reference ................................................................ 225 External Signal ................................................ 225 Internal Signal .................................................. 225 Response Time ........................................................ 225 Comparator Module ......................................................... 223 Comparator Specifications ............................................... 317 Comparator Voltage Reference ....................................... 229 Accuracy and Error .................................................. 230 Associated Registers ............................................... 231 Configuring .............................................................. 229 Connection Considerations ...................................... 230 Effects of a RESET .................................................. 230 Operation During SLEEP ......................................... 230 Compare (CCP Module) .................................................. 152 Associated Registers ............................................... 153 CCP Pin Configuration ............................................. 152 CCPR1 Register ...................................................... 152 Software Interrupt .................................................... 152 Special Event Trigger ...............................138, 145, 152 Timer1/Timer3 Mode Selection ................................ 152 Compare (CCP2 Module) Special Event Trigger .............................................. 220 Configuration Bits ............................................................ 239 Context Saving During Interrupts ..................................... 102 Control Registers EECON1 and EECON2 ............................................. 62 TABLAT (Table Latch) Register ................................. 64 TBLPTR (Table Pointer) Register .............................. 64 Conversion Considerations .............................................. 348 CPFSEQ .......................................................................... 276 CPFSGT .......................................................................... 277 CPFSLT ........................................................................... 277
C
CALL ................................................................................ 274 Capture (CCP Module) ..................................................... 151 Associated Registers ............................................... 153 CCP Pin Configuration ............................................. 151 CCPR1H:CCPR1L Registers ................................... 151 Software Interrupt ..................................................... 151 Timer1/Timer3 Mode Selection ................................ 151 Capture/Compare/PWM (CCP) ........................................ 149 Capture Mode. See Capture CCP Mode and Timer Resources ............................ 150 CCPRxH Register .................................................... 150 CCPRxL Register ..................................................... 150 Compare Mode. See Compare Interconnect Configurations ..................................... 150 Module Configuration ............................................... 150 PWM Mode. See PWM Capture/Compare/PWM Requirements ........................... 328 CLKO and I/O Timing Requirements ....................... 323, 324 Clocking Scheme/Instruction Cycle .................................... 44 CLRF ................................................................................ 275 CLRWDT .......................................................................... 275 Code Examples 16 x 16 Signed Multiply Routine ................................. 86 16 x 16 Unsigned Multiply Routine ............................. 86 8 x 8 Signed Multiply Routine ..................................... 85 8 x 8 Unsigned Multiply Routine ................................. 85 Changing Between Capture Prescalers ................... 151 Data EEPROM Read ................................................. 81 Data EEPROM Refresh Routine ................................ 82 Data EEPROM Write .................................................. 81 Erasing a FLASH Program Memory Row .................. 66 Fast Register Stack .................................................... 44 How to Clear RAM (Bank 1) Using Indirect Addressing ............................................ 57 Implementing a Real-Time Clock Using a Timer1 Interrupt Service .................................. 139
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D
Data EEPROM Memory Associated Registers ................................................. 83 EEADR Register ........................................................ 79 EEADRH Register ...................................................... 79 EECON1 Register ...................................................... 79 EECON2 Register ...................................................... 79 Operation During Code Protect .................................. 82 Protection Against Spurious Write ............................. 82 Reading ...................................................................... 81 Using .......................................................................... 82 Write Verify ................................................................ 82 Writing ........................................................................ 81 Data Memory ...................................................................... 47 General Purpose Registers ........................................ 47 Map for PIC18FX520 Devices ................................... 48 Map for PIC18FX620/X720 Devices .......................... 49 Special Function Registers ........................................ 47 DAW ................................................................................. 278 DC Characteristics PIC18FXX20 (Industrial and Extended), PIC18LFXX20 (Industrial) ................................ 315 Power-down and Supply Current ............................. 311 Supply Voltage ......................................................... 310 DCFSNZ ........................................................................... 279 DECF ............................................................................... 278 DECFSZ ........................................................................... 279 Development Support ...................................................... 301 Device Differences ........................................................... 347 Direct Addressing ............................................................... 58 Direct Addressing ....................................................... 56 Table Pointer Boundaries Based on Operation ....................... 64 Table Pointer Boundaries .......................................... 64 Table Reads and Table Writes .................................. 61 Write Sequence ......................................................... 68 Writing To .................................................................. 67 Protection Against Spurious Writes ................... 70 Unexpected Termination ................................... 70 Write Verify ........................................................ 70
G
General Call Address Support ......................................... 180 GOTO .............................................................................. 280
H
Hardware Multiplier ............................................................ 85 Introduction ................................................................ 85 Operation ................................................................... 85 Performance Comparison .......................................... 85 HS/PLL .............................................................................. 23
I
I/O Ports ........................................................................... 103 I2C Bus Data Requirements (Slave Mode) ...................... 335 I2C Bus START/STOP Bits Requirements (Slave Mode) ........................................................... 334 I2C Mode General Call Address Support ................................. 180 Master Mode Operation ......................................................... 182 Master Mode Transmit Sequence ............................ 182 Read/Write Bit Information (R/W Bit) ................170, 171 Serial Clock (RC3/SCK/SCL) ................................... 171 ID Locations ..............................................................239, 257 INCF ................................................................................ 280 INCFSZ ............................................................................ 281 In-Circuit Debugger .......................................................... 257 Resources (Table) ................................................... 257 In-Circuit Serial Programming (ICSP) .......................239, 257 Indirect Addressing ............................................................ 58 INDF and FSR Registers ........................................... 57 Operation ................................................................... 57 Indirect Addressing Operation ........................................... 58 Indirect File Operand ......................................................... 47 INFSNZ ............................................................................ 281 Instruction Cycle ................................................................ 44 Instruction Flow/Pipelining ................................................. 45 Instruction Format ............................................................ 261 Instruction Set .................................................................. 259 ADDLW .................................................................... 265 ADDWF .................................................................... 265 ADDWFC ................................................................. 266 ANDLW .................................................................... 266 ANDWF .................................................................... 267 BC ............................................................................ 267 BCF ......................................................................... 268 BN ............................................................................ 268 BNC ......................................................................... 269 BNN ......................................................................... 269 BNOV ...................................................................... 270 BNZ ......................................................................... 270 BOV ......................................................................... 273 BRA ......................................................................... 271
E
Electrical Characteristics .................................................. 307 Errata ................................................................................... 5 Example SPI Mode Requirements (Master Mode, CKE = 0) .................................................................. 330 Example SPI Mode Requirements (Master Mode, CKE = 1) .................................................................. 331 Example SPI Mode Requirements (Slave Mode CKE = 0) .................................................................. 332 Example SPI Slave Mode Requirements (CKE = 1) ........ 333 Extended Microcontroller Mode ......................................... 71 External Clock Timing Requirements ............................... 322 External Memory Interface ................................................. 71 16-bit Byte Select Mode ............................................. 75 16-bit Byte Write Mode .............................................. 73 16-bit Mode ................................................................ 73 16-bit Mode Timing .................................................... 76 16-bit Word Write Mode ............................................. 74 PIC18F8X20 External Bus - I/O Port Functions ......... 72 Program Memory Modes and External Memory Interface ............................................... 71
F
Firmware Instructions ....................................................... 259 FLASH Program Memory ................................................... 61 Associated Registers ................................................. 70 Control Registers ....................................................... 62 Erase Sequence ........................................................ 66 Erasing ....................................................................... 66 Operation During Code Protect .................................. 70 Reading ...................................................................... 65
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BSF .......................................................................... 271 BTFSC ..................................................................... 272 BTFSS ...................................................................... 272 BTG .......................................................................... 273 BZ ............................................................................. 274 CALL ........................................................................ 274 CLRF ........................................................................ 275 CLRWDT .................................................................. 275 COMF ....................................................................... 276 CPFSEQ .................................................................. 276 CPFSGT ................................................................... 277 CPFSLT ................................................................... 277 DAW ......................................................................... 278 DCFSNZ ................................................................... 279 DECF ....................................................................... 278 DECFSZ ................................................................... 279 GOTO ....................................................................... 280 INCF ......................................................................... 280 INCFSZ .................................................................... 281 INFSNZ .................................................................... 281 IORLW ..................................................................... 282 IORWF ..................................................................... 282 LFSR ........................................................................ 283 MOVF ....................................................................... 283 MOVFF ..................................................................... 284 MOVLB ..................................................................... 284 MOVLW .................................................................... 285 MOVWF ................................................................... 285 MULLW .................................................................... 286 MULWF .................................................................... 286 NEGF ....................................................................... 287 NOP ......................................................................... 287 POP .......................................................................... 288 PUSH ....................................................................... 288 RCALL ...................................................................... 289 RESET ..................................................................... 289 RETFIE .................................................................... 290 RETLW ..................................................................... 290 RETURN .................................................................. 291 RLCF ........................................................................ 291 RLNCF ..................................................................... 292 RRCF ....................................................................... 292 RRNCF ..................................................................... 293 SETF ........................................................................ 293 SLEEP ...................................................................... 294 SUBFWB .................................................................. 294 SUBLW .................................................................... 295 SUBWF .................................................................... 295 SUBWFB .................................................................. 296 SWAPF .................................................................... 296 TBLRD ..................................................................... 297 TBLWT ..................................................................... 298 TSTFSZ .................................................................... 299 XORLW .................................................................... 299 XORWF .................................................................... 300 Summary Table ........................................................ 262 INT Interrupt (RB0/INT). See Interrupt Sources INTCON Registers ............................................................. 89 Inter-Integrated Circuit. See I2C Interrupt Sources .............................................................. 239 A/D Conversion Complete ........................................ 217 Capture Complete (CCP) ......................................... 151 Compare Complete (CCP) ....................................... 152 INT0 ......................................................................... 102 Interrupt-on-Change (RB7:RB4) .............................. 106 PORTB, Interrupt-on-Change .................................. 102 RB0/INT Pin, External .............................................. 102 TMR0 ....................................................................... 102 TMR0 Overflow ........................................................ 133 TMR1 Overflow .................................................135, 138 TMR2 to PR2 Match ................................................ 142 TMR2 to PR2 Match (PWM) .............................141, 154 TMR3 Overflow .................................................143, 145 TMR4 to PR4 Match ................................................ 148 TMR4 to PR4 Match (PWM) .................................... 147 Interrupts ............................................................................ 87 Control Registers ....................................................... 89 Enable Registers ....................................................... 95 Flag Registers ............................................................ 92 Logic .......................................................................... 88 Priority Registers ....................................................... 98 RESET Control Registers ........................................ 101 IORLW ............................................................................. 282 IORWF ............................................................................. 282 IPR Registers ..................................................................... 98
K
Key Features Easy Migration ............................................................. 7 Expanded Memory ....................................................... 7 External Memory Interface ........................................... 7 Other Special Features ................................................ 7
L
LFSR ................................................................................ 283 Low Voltage Detect .......................................................... 233 Characteristics ......................................................... 318 Converter Characteristics ........................................ 318 Effects of a RESET .................................................. 237 Operation ................................................................. 236 Current Consumption ....................................... 237 During SLEEP ................................................. 237 Reference Voltage Set Point ........................... 237 Typical Application ................................................... 233 Low Voltage ICSP Programming ..................................... 257 LVD. See Low Voltage Detect. ........................................ 233
M
Master SSP (MSSP) Module Overview .................................................................. 157 Master SSP I2C Bus Data Requirements ........................ 337 Master SSP I2C Bus START/STOP Bits Requirements .......................................................... 336 Master Synchronous Serial Port (MSSP). See MSSP. Master Synchronous Serial Port. See MSSP Memory Organization Data Memory ............................................................. 47 Memory Programming Requirements .............................. 319 Microcontroller Mode ......................................................... 71 Microprocessor Mode ........................................................ 71 Microprocessor with Boot Block Mode ............................... 71 Migration from High-End to Enhanced Devices ............... 349 Migration from Mid-Range to Enhanced Devices ............ 348 MOVF .............................................................................. 283 MOVFF ............................................................................ 284 MOVLB ............................................................................ 284
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MOVLW ............................................................................ 285 MOVWF ........................................................................... 285 MPLAB C17 and MPLAB C18 C Compilers ..................... 302 MPLAB ICD In-Circuit Debugger ...................................... 303 MPLAB ICE High Performance Universal In-Circuit Emulator with MPLAB IDE ....................................... 303 MPLAB Integrated Development Environment Software .............................................. 301 MPLINK Object Linker/MPLIB Object Librarian ............... 302 MSSP ............................................................................... 157 ACK Pulse ........................................................ 170, 171 Clock Stretching ....................................................... 176 10-bit Slave Receive Mode (SEN = 1) ............. 176 10-bit Slave Transmit Mode ............................. 176 7-bit Slave Receive Mode (SEN = 1) ............... 176 7-bit Slave Transmit Mode ............................... 176 Clock Synchronization and the CKP bit (SEN = 1) ......................................................... 177 Control Registers (general) ...................................... 157 Enabling SPI I/O ...................................................... 161 I2C Mode .................................................................. 166 Acknowledge Sequence Timing ....................... 190 Baud Rate Generator ....................................... 183 Bus Collision During a Repeated START Condition .................................................. 194 Bus Collision During a START Condition ......... 192 Bus Collision During a STOP Condition ........... 195 Clock Arbitration ............................................... 184 Effect of a RESET ............................................ 191 I2C Clock Rate w/BRG ..................................... 183 Master Mode .................................................... 181 Reception ................................................. 187 Repeated START Timing ......................... 186 Master Mode START Condition ....................... 185 Master Mode Transmission .............................. 187 Multi-Master Communication, Bus Collision and Arbitration ......................................... 191 Multi-Master Mode ........................................... 191 Registers .......................................................... 166 SLEEP Operation ............................................. 191 STOP Condition Timing ................................... 190 I2C Mode. See I2C Module Operation .................................................... 170 Operation ................................................................. 160 Slave Mode .............................................................. 170 Addressing ....................................................... 170 Reception ......................................................... 171 Transmission .................................................... 171 SPI Master Mode .................................................... 162 SPI Clock ......................................................... 162 SPI Master Mode ..................................................... 162 SPI Mode ................................................................. 157 SPI Mode. See SPI SPI Slave Mode ....................................................... 163 Select Synchronization .................................... 163 SSPBUF Register .................................................... 162 SSPSR Register ...................................................... 162 Typical Connection .................................................. 161 MSSP Module SPI Master./Slave Connection ................................. 161 MULLW ............................................................................ 286 MULWF ............................................................................ 286
N
NEGF ............................................................................... 287 NOP ................................................................................. 287
O
OPCODE Field Descriptions ............................................ 260 OPTION_REG Register PSA Bit .................................................................... 133 T0CS Bit .................................................................. 133 T0PS2:T0PS0 Bits ................................................... 133 T0SE Bit .................................................................. 133 Oscillator Configuration ..................................................... 21 EC .............................................................................. 21 ECIO .......................................................................... 21 HS .............................................................................. 21 HS + PLL ................................................................... 21 LP .............................................................................. 21 RC ............................................................................. 21 RCIO .......................................................................... 21 XT .............................................................................. 21 Oscillator Selection .......................................................... 239 Oscillator Switching Feature .............................................. 24 Oscillator Transitions ................................................. 26 System Clock Switch Bit ............................................ 25 Oscillator, Timer1 .............................................. 135, 137, 145 Oscillator, Timer3 ............................................................. 143 Oscillator, WDT ................................................................ 250
P
Packaging ........................................................................ 343 Details ...................................................................... 344 Marking .................................................................... 343 Parallel Slave Port (PSP) ..........................................111, 128 Associated Registers ............................................... 130 RE0/RD/AN5 Pin ..................................................... 128 RE1/WR/AN6 Pin ..................................................... 128 RE2/CS/AN7 Pin ...................................................... 128 Read Waveforms ..................................................... 130 Select (PSPMODE Bit) .....................................111, 128 Write Waveforms ..................................................... 129 Parallel Slave Port Requirements (PIC18F8X20) ............ 329 PICDEM 1 Low Cost PICmicro Demonstration Board ............................................... 304 PICDEM 17 Demonstration Board ................................... 304 PICDEM 2 Low Cost PIC16CXX Demonstration Board ............................................... 304 PICSTART Plus Entry Level Development Programmer ............................................................. 303 PIE Registers ..................................................................... 95 Pin Functions AVDD .......................................................................... 20 AVSS .......................................................................... 20 MCLR/VPP ................................................................. 11 OSC1/CLKI ................................................................ 11 OSC2/CLKO/RA6 ...................................................... 11 RA0/AN0 .................................................................... 12 RA1/AN1 .................................................................... 12 RA2/AN2/VREF- ......................................................... 12 RA3/AN3/VREF+ ........................................................ 12 RA4/T0CKI ................................................................ 12 RA5/AN4/LVDIN ........................................................ 12 RA6 ............................................................................ 12 RB0/INT0 ................................................................... 13
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RB1/INT1 ................................................................... 13 RB2/INT2 ................................................................... 13 RB3/INT3/CCP2 ......................................................... 13 RB4/KBI0 ................................................................... 13 RB5/KBI1/PGM .......................................................... 13 RB6/KBI2/PGC ........................................................... 13 RB7/KBI3/PGD ........................................................... 13 RC0/T1OSO/T13CKI .................................................. 14 RC1/T1OSI/CCP2 ...................................................... 14 RC2/CCP1 ................................................................. 14 RC3/SCK/SCL ............................................................ 14 RC4/SDI/SDA ............................................................. 14 RC5/SDO ................................................................... 14 RC6/TX1/CK1 ............................................................ 14 RC7/RX1/DT1 ............................................................ 14 RD0/PSP0/AD0 .......................................................... 15 RD1/PSP1/AD1 .......................................................... 15 RD2/PSP2/AD2 .......................................................... 15 RD3/PSP3/AD3 .......................................................... 15 RD4/PSP4/AD4 .......................................................... 15 RD5/PSP5/AD5 .......................................................... 15 RD6/PSP6/AD6 .......................................................... 15 RD7/PSP7/AD7 .......................................................... 15 RE0/RD/AD8 .............................................................. 16 RE1/WR/AD9 ............................................................. 16 RE2/CS/AD10 ............................................................ 16 RE3/AD11 .................................................................. 16 RE4/AD12 .................................................................. 16 RE5/AD13 .................................................................. 16 RE6/AD14 .................................................................. 16 RE7/CCP2/AD15 ........................................................ 16 RF0/AN5 .................................................................... 17 RF1/AN6/C2OUT ....................................................... 17 RF2/AN7/C1OUT ....................................................... 17 RF3/AN8 .................................................................... 17 RF4/AN9 .................................................................... 17 RF5/AN10/CVREF ....................................................... 17 RF6/AN11 .................................................................. 17 RF7/SS ....................................................................... 17 RG0/CCP3 ................................................................. 18 RG1/TX2/CK2 ............................................................ 18 RG2/RX2/DT2 ............................................................ 18 RG3/CCP4 ................................................................. 18 RG4/CCP5 ................................................................. 18 RH0/A16 ..................................................................... 19 RH1/A17 ..................................................................... 19 RH2/A18 ..................................................................... 19 RH3/A19 ..................................................................... 19 RH4/AN12 .................................................................. 19 RH5/AN13 .................................................................. 19 RH6/AN14 .................................................................. 19 RH7/AN15 .................................................................. 19 RJ0/ALE ..................................................................... 20 RJ1/OE ....................................................................... 20 RJ2/WRL .................................................................... 20 RJ3/WRH ................................................................... 20 RJ4/BA0 ..................................................................... 20 RJ5/CE ....................................................................... 20 RJ6/LB ....................................................................... 20 RJ7/UB ....................................................................... 20 VDD ............................................................................. 20 VSS ............................................................................. 20 PIR Registers ..................................................................... 92 PLL Clock Timing Specifications ...................................... 322 PLL Lock Time-out ............................................................. 30 Pointer, FSR ...................................................................... 57 POP ................................................................................. 288 POR. See Power-on Reset PORTA Associated Registers ............................................... 105 Functions ................................................................. 105 LATA Register ......................................................... 103 PORTA Register ...................................................... 103 TRISA Register ........................................................ 103 PORTB Associated Registers ............................................... 108 Functions ................................................................. 108 LATB Register ......................................................... 106 PORTB Register ...................................................... 106 RB0/INT Pin, External .............................................. 102 TRISB Register ........................................................ 106 PORTC Associated Registers ............................................... 110 Functions ................................................................. 110 LATC Register ......................................................... 109 PORTC Register ...................................................... 109 RC3/SCK/SCL Pin ................................................... 171 TRISC Register .................................................109, 197 PORTD ............................................................................ 128 Associated Registers ............................................... 113 Functions ................................................................. 113 LATD Register ......................................................... 111 Parallel Slave Port (PSP) Function .......................... 111 PORTD Register ...................................................... 111 TRISD Register ........................................................ 111 PORTE Analog Port Pins ...................................................... 128 Associated Registers ............................................... 116 Functions ................................................................. 116 LATE Register ......................................................... 114 PORTE Register ...................................................... 114 PSP Mode Select (PSPMODE Bit) ...................111, 128 RE0/RD/AN5 Pin ..................................................... 128 RE1/WR/AN6 Pin ..................................................... 128 RE2/CS/AN7 Pin ...................................................... 128 TRISE Register ........................................................ 114 PORTF Associated Registers ............................................... 119 Functions ................................................................. 119 LATF Register .......................................................... 117 PORTF Register ...................................................... 117 TRISF Register ........................................................ 117 PORTG Associated Registers ............................................... 121 Functions ................................................................. 121 LATG Register ......................................................... 120 PORTG Register ...................................................... 120 TRISG Register ................................................120, 197 PORTH Associated Registers ............................................... 124 Functions ................................................................. 124 LATH Register ......................................................... 122 PORTH Register ...................................................... 122 TRISH Register ........................................................ 122
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PORTJ Associated Registers ............................................... 127 Functions ................................................................. 127 LATJ Register .......................................................... 125 PORTJ Register ....................................................... 125 TRISJ Register ......................................................... 125 Postscaler, WDT Assignment (PSA Bit) .............................................. 133 Rate Select (T0PS2:T0PS0 Bits) ............................. 133 Switching Between Timer0 and WDT ...................... 133 Power-down Mode. See SLEEP Power-on Reset (POR) .............................................. 30, 239 Oscillator Start-up Timer (OST) ......................... 30, 239 Power-up Timer (PWRT) ................................... 30, 239 Time-out Sequence .................................................... 30 Prescaler, Capture ........................................................... 151 Prescaler, Timer0 ............................................................. 133 Assignment (PSA Bit) .............................................. 133 Rate Select (T0PS2:T0PS0 Bits) ............................. 133 Switching Between Timer0 and WDT ...................... 133 Prescaler, Timer2 ............................................................. 154 PRO MATE II Universal Device Programmer .................. 303 Product Identification System ........................................... 363 Program Counter PCL, PCLATH and PCLATU Registers ..................... 44 Program Memory ............................................................... 39 Access for PIC18F8X20 Program Memory Modes .................................................. 40 Instructions ................................................................. 45 Interrupt Vector .......................................................... 39 Map and Stack for PIC18FXX20 ................................ 40 Maps for PIC18F8X20 Program Memory Modes .................................................. 41 PIC18F8X20 Modes ................................................... 39 RESET Vector ............................................................ 39 Program Memory Write Timing Requirements ................. 325 Program Verification and Code Protection ....................... 253 Associated Registers ............................................... 253 Configuration Register Protection ............................ 257 Data EEPROM Code Protection .............................. 257 Memory Code Protection ......................................... 255 Programming, Device Instructions ................................... 259 PSP.See Parallel Slave Port. Pulse Width Modulation. See PWM (CCP Module). PUSH ............................................................................... 288 PWM (CCP Module) ......................................................... 154 Associated Registers ............................................... 155 CCPR1H:CCPR1L Registers ................................... 154 Duty Cycle ................................................................ 154 Example Frequencies/Resolutions .......................... 155 Period ....................................................................... 154 Setup for PWM Operation ........................................ 155 TMR2 to PR2 Match ........................................ 141, 154 TMR4 to PR4 Match ................................................ 147
R
RAM. See Data Memory RC Oscillator ...................................................................... 22 RCALL ............................................................................. 289 RCON Registers .............................................................. 101 RCSTA Register SPEN Bit .................................................................. 197 Register File ....................................................................... 47 Registers ADCON0 (A/D Control 0) ......................................... 213 ADCON1 (A/D Control 1) ......................................... 214 ADCON2 (A/D Control 2) ......................................... 215 CCPxCON (Capture/Compare/ PWM Control) .................................................. 149 CMCON (Comparator Control) ................................ 223 CONFIG1H (Configuration 1 High) .......................... 241 CONFIG2H (Configuration 2 High) .......................... 242 CONFIG2L (Configuration 2 Low) ........................... 241 CONFIG3H (Configuration 3 High) .......................... 243 CONFIG3L (Configuration 3 Low) ........................... 242 CONFIG3L (Configuration Byte) ................................ 41 CONFIG4L (Configuration 4 Low) ........................... 243 CONFIG5H (Configuration 5 High) .......................... 245 CONFIG5L (Configuration 5 Low) ........................... 244 CONFIG6H (Configuration 6 High) .......................... 247 CONFIG6L (Configuration 6 Low) ........................... 246 CONFIG7H (Configuration 7 High) .......................... 249 CONFIG7L (Configuration 7 Low) ........................... 248 CVRCON (Comparator Voltage Reference Control) .......................................... 229 Device ID 1 .............................................................. 249 Device ID 2 .............................................................. 249 EECON1 (Data EEPROM Control 1) ....................63, 80 INTCON (Interrupt Control) ........................................ 89 INTCON2 (Interrupt Control 2) ................................... 90 INTCON3 (Interrupt Control 3) ................................... 91 IPR1 (Peripheral Interrupt Priority 1) ......................... 98 IPR2 (Peripheral Interrupt Priority 2) ......................... 99 IPR3 (Peripheral Interrupt Priority 3) ....................... 100 LVDCON (LVD Control) ........................................... 235 MEMCON (Memory Control) ..................................... 71 OSCCON ................................................................... 25 PIE1 (Peripheral Interrupt Enable 1) .......................... 95 PIE2 (Peripheral Interrupt Enable 2) .......................... 96 PIE3 (Peripheral Interrupt Enable 3) .......................... 97 PIR1 (Peripheral Interrupt Request 1) ....................... 92 PIR2 (Peripheral Interrupt Request 2) ....................... 93 PIR3 (Peripheral Interrupt Request 3) ....................... 94 PSPCON (Parallel Slave Port Control) .................... 129 RCON ........................................................................ 31 RCON (Reset Control) ........................................60, 101 RCSTAx (Receive Status and Control) .................... 199 SSPCON1 (MSSP Control 1) - I2C Mode ................ 168 SSPCON1 (MSSP Control 1) - SPI Mode ............... 159 SSPCON2 (MSSP Control 2) - I2C Mode ................ 169 SSPSTAT (MSSP Status) - I2C Mode ..................... 167 SSPSTAT (MSSP Status) - SPI Mode ..................... 158 STATUS .................................................................... 59 STKPTR (Stack Pointer) ............................................ 43 Summary ..............................................................52-55
Q
Q Clock ............................................................................ 154
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PIC18FXX20
T0CON (Timer0 Control) .......................................... 131 T1CON (Timer 1 Control) ......................................... 135 T2CON (Timer 2 Control) ......................................... 141 T3CON (Timer3 Control) .......................................... 143 T4CON (Timer4 Control) .......................................... 147 TXSTAx (Transmit Status and Control) .................... 198 WDTCON (Watchdog Timer Control) ....................... 250 RESET ............................................................... 29, 239, 289 MCLR Reset ............................................................... 29 MCLR Reset during SLEEP ....................................... 29 Power-on Reset (POR) .............................................. 29 Programmable Brown-out Reset (PBOR) .................. 29 RESET Instruction ...................................................... 29 Stack Full Reset ......................................................... 29 Stack Underflow Reset ............................................... 29 Watchdog Timer (WDT) Reset ................................... 29 RESET, Watchdog Timer, Oscillator Start-up Timer, Power-up Timer and Brown-out Reset Requirements ........................................................... 326 RETFIE ............................................................................ 290 RETLW ............................................................................. 290 RETURN .......................................................................... 291 Return Address Stack and Associated Registers .......................................... 43 Revision History ............................................................... 347 RLCF ................................................................................ 291 RLNCF ............................................................................. 292 RRCF ............................................................................... 292 RRNCF ............................................................................. 293 SS .................................................................................... 157 SSP TMR2 Output for Clock Shift .............................141, 142 TMR4 Output for Clock Shift .................................... 148 SSPOV Status Flag ......................................................... 187 SSPSTAT Register R/W Bit ..............................................................170, 171 STATUS Bits Significance and Initialization Condition for RCON Register .................................................. 31 SUBFWB ......................................................................... 294 SUBLW ............................................................................ 295 SUBWF ............................................................................ 295 SUBWFB ......................................................................... 296 SWAPF ............................................................................ 296
T
Table Pointer Operations (table) ........................................ 64 TBLRD ............................................................................. 297 TBLWT ............................................................................. 298 Time-out in Various Situations ........................................... 31 Timer0 .............................................................................. 131 16-bit Mode Timer Reads and Writes ...................... 133 Associated Registers ............................................... 133 Clock Source Edge Select (T0SE Bit) ..................... 133 Clock Source Select (T0CS Bit) ............................... 133 Operation ................................................................. 133 Overflow Interrupt .................................................... 133 Prescaler. See Prescaler, Timer0 Timer0 and Timer1 External Clock Requirements .......................................................... 327 Timer1 .............................................................................. 135 16-bit Read/Write Mode ........................................... 138 Associated Registers ............................................... 139 Operation ................................................................. 136 Oscillator ...........................................................135, 137 Overflow Interrupt .............................................135, 138 Special Event Trigger (CCP) ............................138, 152 TMR1H Register ...................................................... 135 TMR1L Register ....................................................... 135 Use as a Real-Time Clock ....................................... 138 Timer2 .............................................................................. 141 Associated Registers ............................................... 142 Operation ................................................................. 141 Postscaler. See Postscaler, Timer2 PR2 Register ....................................................141, 154 Prescaler. See Prescaler, Timer2 SSP Clock Shift ................................................141, 142 TMR2 Register ......................................................... 141 TMR2 to PR2 Match Interrupt ...................141, 142, 154 Timer3 .............................................................................. 143 Associated Registers ............................................... 145 Operation ................................................................. 144 Oscillator ...........................................................143, 145 Overflow Interrupt .............................................143, 145 Special Event Trigger (CCP) ................................... 145 TMR3H Register ...................................................... 143 TMR3L Register ....................................................... 143
S
SCI. See USART SCK .................................................................................. 157 SDI ................................................................................... 157 SDO ................................................................................. 157 Serial Clock, SCK ............................................................. 157 Serial Communication Interface. See USART Serial Data In, SDI ........................................................... 157 Serial Data Out, SDO ....................................................... 157 Serial Peripheral Interface. See SPI SETF ................................................................................ 293 Slave Select, SS .............................................................. 157 SLEEP .............................................................. 239, 252, 294 Software Simulator (MPLAB SIM) .................................... 302 Special Event Trigger. See Compare Special Features of the CPU ............................................ 239 Configuration Registers .................................... 241-249 Special Function Registers ................................................ 47 Map ............................................................................ 50 SPI Serial Clock .............................................................. 157 Serial Data In ........................................................... 157 Serial Data Out ......................................................... 157 Slave Select ............................................................. 157 SPI Mode ................................................................. 157 SPI Master/Slave Connection .......................................... 161 SPI Module Associated Registers ............................................... 165 Bus Mode Compatibility ........................................... 165 Effects of a RESET .................................................. 165 Master/Slave Connection ......................................... 161 Slave Mode .............................................................. 163 SLEEP Operation ..................................................... 165
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PIC18FXX20
Timer4 .............................................................................. 147 Associated Registers ............................................... 148 Operation ................................................................. 147 Postscaler. See Postscaler, Timer4 PR4 Register ............................................................ 147 Prescaler. See Prescaler, Timer4 SSP Clock Shift ........................................................ 148 TMR4 Register ......................................................... 147 TMR4 to PR4 Match Interrupt .......................... 147, 148 Timing Diagrams A/D Conversion ........................................................ 340 Acknowledge Sequence .......................................... 190 Baud Rate Generator with Clock Arbitration ......................................................... 184 BRG Reset Due to SDA Arbitration During START Condition ............................................. 193 Brown-out Reset (BOR) ........................................... 326 Bus Collision During a Repeated START Condition (Case 1) ........................................... 194 Bus Collision During a Repeated START Condition (Case 2) ........................................... 194 Bus Collision During a START Condition (SCL = 0) ......................................................... 193 Bus Collision During a STOP Condition (Case 1) ........................................................... 195 Bus Collision During a STOP Condition (Case 2) ........................................................... 195 Bus Collision During START Condition (SDA only) ........................................................ 192 Bus Collision for Transmit and Acknowledge ........... 191 Capture/Compare/PWM (All CCP Modules) ............ 328 CLKO and I/O .......................................................... 323 Clock Synchronization ............................................. 177 Clock/Instruction Cycle .............................................. 44 Example SPI Master Mode (CKE = 0) ..................... 330 Example SPI Master Mode (CKE = 1) ..................... 331 Example SPI Slave Mode (CKE = 0) ....................... 332 Example SPI Slave Mode (CKE = 1) ....................... 333 External Clock (All Modes except PLL) .................... 322 External Memory Bus for SLEEP (Microprocessor Mode) ...................................... 77 External Memory Bus for TBLRD (Extended Microcontroller Mode) ........................................ 76 External Memory Bus for TBLRD (Microprocessor Mode) ...................................... 76 I2C Bus Data ............................................................ 334 I2C Bus START/STOP Bits ...................................... 334 I2C Master Mode (7 or 10-bit Transmission) ............ 188 I2C Master Mode (7-bit Reception) .......................... 189 I2C Master Mode First START Bit Timing ................ 185 I2C Slave Mode (10-bit Reception, SEN = 0) .......................................................... 174 I2C Slave Mode (10-bit Reception, SEN = 1) .......................................................... 179 I2C Slave Mode (10-bit Transmission) ..................... 175 I2C Slave Mode (7-bit Reception, SEN = 0) ............. 172 I2C Slave Mode (7-bit Reception, SEN = 1) ............. 178 I2C Slave Mode (7-bit Transmission) ....................... 173 Low Voltage Detect .................................................. 236 Master SSP I2C Bus Data ........................................ 336 Master SSP I2C Bus START/STOP Bits .................. 336 Parallel Slave Port (PIC18F8X20) ........................... 329 Program Memory Read ............................................ 324 Program Memory Write ............................................ 325 PWM Output ............................................................ 154 Repeat START Condition ........................................ 186 RESET, Watchdog Timer (WDT), Oscillator Start-up Timer (OST) and Power-up Timer (PWRT) ................................................. 326 Slave Mode General Call Address Sequence (7 or 10-bit Address Mode) .............................. 180 Slave Synchronization ............................................. 163 Slow Rise Time (MCLR Tied to VDD via 1 kOhm Resistor) ............................................... 38 SPI Mode (Master Mode) ......................................... 162 SPI Mode (Slave Mode with CKE = 0) ..................... 164 SPI Mode (Slave Mode with CKE = 1) ..................... 164 STOP Condition Receive or Transmit Mode ............ 190 Synchronous Reception (Master Mode, SREN) ............................................................. 210 Synchronous Transmission ..................................... 209 Synchronous Transmission (Through TXEN) .......... 209 Time-out Sequence on POR w/PLL Enabled (MCLR Tied to VDD via 1 kOhm Resistor) ......... 38 Time-out Sequence on Power-up (MCLR Not Tied to VDD) Case 1 ............................................................... 37 Case 2 ............................................................... 37 Time-out Sequence on Power-up (MCLR Tied to VDD via 1 kOhm Resistor) ............................. 37 Timer0 and Timer1 External Clock .......................... 327 Timing for Transition Between Timer1 and OSC1 (HS with PLL) .......................................... 27 Transition Between Timer1 and OSC1 (HS, XT, LP) ...................................................... 26 Transition Between Timer1 and OSC1 (RC, EC) ............................................................ 27 Transition from OSC1 to Timer1 Oscillator ................ 26 USART Asynchronous Reception ............................ 207 USART Asynchronous Transmission ...................... 205 USART Asynchronous Transmission (Back to Back) ................................................. 205 USART Synchronous Receive (Master/Slave) ................................................. 338 USART Synchronous Transmission (Master/Slave) ................................................. 338 Wake-up from SLEEP via Interrupt .......................... 253 TRISE Register PSPMODE Bit ...................................................111, 128 TSTFSZ ........................................................................... 299 Two-Word Instructions Example Cases .......................................................... 46 TXSTA Register BRGH Bit ................................................................. 200
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PIC18FXX20
U
Universal Synchronous Asynchronous Receiver Transmitter. See USART USART Asynchronous Mode ................................................ 204 Associated Registers, Receive ........................ 207 Associated Registers, Transmit ....................... 205 Receiver ........................................................... 206 Setting up 9-bit Mode with Address Detect ...... 206 Transmitter ....................................................... 204 Baud Rate Generator (BRG) .................................... 200 Associated Registers ....................................... 200 Baud Rate Error, Calculating ........................... 200 Baud Rate Formula .......................................... 200 Baud Rates for Asynchronous Mode (BRGH = 0) .............................................. 202 Baud Rates for Asynchronous Mode (BRGH = 1) .............................................. 203 Baud Rates for Synchronous Mode ................. 201 High Baud Rate Select (BRGH Bit) .................. 200 Sampling .......................................................... 200 Serial Port Enable (SPEN Bit) .................................. 197 Synchronous Master Mode ...................................... 208 Associated Registers, Reception ..................... 210 Associated Registers, Transmit ....................... 208 Reception ......................................................... 210 Transmission .................................................... 208 Synchronous Slave Mode ........................................ 211 Associated Registers, Receive ........................ 212 Associated Registers, Transmit ....................... 211 Reception ......................................................... 212 Transmission .................................................... 211 USART Synchronous Receive Requirements .................. 338 USART Synchronous Transmission Requirements ......... 338
V
Voltage Reference Specifications .................................... 317
W
Wake-up from SLEEP ...............................................239, 252 Using Interrupts ....................................................... 252 Watchdog Timer (WDT) ............................................239, 250 Associated Registers ............................................... 251 Control Register ....................................................... 250 Postscaler ................................................................ 251 Programming Considerations .................................. 250 RC Oscillator ............................................................ 250 Time-out Period ....................................................... 250 WCOL .............................................................................. 185 WCOL Status Flag .................................... 185, 186, 187, 190 WDT Postscaler ............................................................... 250 WWW, On-Line Support ...................................................... 5
X
XORLW ............................................................................ 299 XORWF ........................................................................... 300
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ON-LINE SUPPORT
Microchip provides on-line support on the Microchip World Wide Web site. The web site is used by Microchip as a means to make files and information easily available to customers. To view the site, the user must have access to the Internet and a web browser, such as Netscape(R) or Microsoft(R) Internet Explorer. Files are also available for FTP download from our FTP site.
SYSTEMS INFORMATION AND UPGRADE HOT LINE
The Systems Information and Upgrade Line provides system users a listing of the latest versions of all of Microchip's development systems software products. Plus, this line provides information on how customers can receive the most current upgrade kits.The Hot Line Numbers are: 1-800-755-2345 for U.S. and most of Canada, and 1-480-792-7302 for the rest of the world. 092002
Connecting to the Microchip Internet Web Site
The Microchip web site is available at the following URL: www.microchip.com The file transfer site is available by using an FTP service to connect to: ftp://ftp.microchip.com The web site and file transfer site provide a variety of services. Users may download files for the latest Development Tools, Data Sheets, Application Notes, User's Guides, Articles and Sample Programs. A variety of Microchip specific business information is also available, including listings of Microchip sales offices, distributors and factory representatives. Other data available for consideration is: * Latest Microchip Press Releases * Technical Support Section with Frequently Asked Questions * Design Tips * Device Errata * Job Postings * Microchip Consultant Program Member Listing * Links to other useful web sites related to Microchip Products * Conferences for products, Development Systems, technical information and more * Listing of seminars and events
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DS39609A-page 361
PIC18FXX20
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150. Please list the following information, and use this outline to provide us with your comments about this document. To: RE: Technical Publications Manager Reader Response Total Pages Sent ________
From: Name Company Address City / State / ZIP / Country Telephone: (_______) _________ - _________ Application (optional): Would you like a reply? Device: PIC18FXX20 Questions: 1. What are the best features of this document? Y N Literature Number: DS39609A FAX: (______) _________ - _________
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
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PIC18FXX20
PIC18FXX20 PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO. Device
-
X Temperature Range
/XX Package
XXX Pattern
Examples: a) PIC18LF6620 - I/PT 301 = Industrial temp., TQFP package, Extended VDD limits, QTP pattern #301. PIC18F8720 - I/PT = Industrial temp., TQFP package, normal VDD limits. PIC18F8620 - E/PT = Extended temp., TQFP package, standard VDD limits.
Device
PIC18FXX20(1), PIC18FXX20T(2); VDD range 4.2V to 5.5V PIC18LFXX20(1), PIC18LFXX20T(2); VDD range 2.0V to 5.5V I E PT = = = -40C to +85C (Industrial) -40C to +125C (Extended) TQFP (Thin Quad Flatpack)
b) c)
Temperature Range Package Pattern
Note 1: F LF 2: T
= Standard Voltage Range = Extended Voltage Range = in tape and reel
QTP, SQTP, Code or Special Requirements (blank otherwise)
Sales and Support
Data Sheets Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following: 1. 2. 3. Your local Microchip sales office The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277 The Microchip Worldwide Site (www.microchip.com)
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using. New Customer Notification System Register on our web site (www.microchip.com/cn) to receive the most current information on our products.
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DS39609A-page 363
WORLDWIDE SALES AND SERVICE
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12/05/02
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