View PIC16F685-IMLQTP_552776.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

PIC16F631/677/685/687/689/690 Data Sheet
20-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology
(c) 2007 Microchip Technology Inc.
DS41262D
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in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.
Trademarks The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, KEELOQ logo, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC, and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, Linear Active Thermistor, Migratable Memory, MXDEV, MXLAB, PS logo, SEEVAL, SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. 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) 2007, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper.
Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona, Gresham, Oregon and Mountain View, California. The Company's quality system processes and procedures are for its PIC(R) MCUs and dsPIC(R) DSCs, KEELOQ(R) code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip's quality system for the design and manufacture of development systems is ISO 9001:2000 certified.
DS41262D-page ii
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
20-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology
High-Performance RISC CPU:
* Only 35 instructions to learn: - All single-cycle instructions except branches * Operating speed: - DC - 20 MHz oscillator/clock input - DC - 200 ns instruction cycle * Interrupt capability * 8-level deep hardware stack * Direct, Indirect and Relative Addressing modes
Low-Power Features:
* Standby Current: - 50 nA @ 2.0V, typical * Operating Current: - 11 A @ 32 kHz, 2.0V, typical - 220 A @ 4 MHz, 2.0V, typical * Watchdog Timer Current: - <1 A @ 2.0V, typical
Peripheral Features: Special Microcontroller Features:
* Precision Internal Oscillator: - Factory calibrated to 1% - Software selectable frequency range of 8 MHz to 32 kHz - Software tunable - Two-Speed Start-up mode - Crystal fail detect for critical applications - Clock mode switching during operation for power savings * Power-Saving Sleep mode * Wide operating voltage range (2.0V-5.5V) * Industrial and Extended Temperature range * Power-on Reset (POR) * Power-up Timer (PWRTE) and Oscillator Start-up Timer (OST) * Brown-out Reset (BOR) with software control option * Enhanced low-current Watchdog Timer (WDT) with on-chip oscillator (software selectable nominal 268 seconds with full prescaler) with software enable * Multiplexed Master Clear/Input pin * Programmable code protection * High Endurance Flash/EEPROM cell: - 100,000 write Flash endurance - 1,000,000 write EEPROM endurance - Flash/Data EEPROM retention: > 40 years * Enhanced USART module: - Supports RS-485, RS-232 and LIN 2.0 - Auto-Baud Detect - Auto-wake-up on Start bit * 17 I/O pins and 1 input only pin: - High current source/sink for direct LED drive - Interrupt-on-Change pin - Individually programmable weak pull-ups - Ultra Low-Power Wake-up (ULPWU) * Analog Comparator module with: - Two analog comparators - Programmable on-chip voltage reference (CVREF) module (% of VDD) - Comparator inputs and outputs externally accessible - SR Latch mode - Timer 1 Gate Sync Latch - Fixed 0.6V VREF * A/D Converter: - 10-bit resolution and 12 channels * Timer0: 8-bit timer/counter with 8-bit programmable prescaler * Enhanced Timer1: - 16-bit timer/counter with prescaler - External Timer1 Gate (count enable) - Option to use OSC1 and OSC2 in LP mode as Timer1 oscillator if INTOSC mode selected * Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler * Enhanced Capture, Compare, PWM+ module: - 16-bit Capture, max resolution 12.5 ns - Compare, max resolution 200 ns - 10-bit PWM with 1, 2 or 4 output channels, programmable "dead time", max frequency 20 kHz - PWM output steering control * Synchronous Serial Port (SSP): - SPI mode (Master and Slave) * I2CTM (Master/Slave modes): - I2CTM address mask * In-Circuit Serial ProgrammingTM (ICSPTM) via two pins
(c) 2007 Microchip Technology Inc.
DS41262D-page 1
PIC16F631/677/685/687/689/690
Program Memory Device Flash (words) PIC16F631 PIC16F677 PIC16F685 PIC16F687 PIC16F689 PIC16F690 1024 2048 4096 2048 4096 4096 SRAM EEPROM (bytes) (bytes) 64 128 256 128 256 256 128 256 256 256 256 256 18 18 18 18 18 18 Data Memory I/O 10-bit A/D Comparators (ch) -- 12 12 12 12 12 2 2 2 2 2 2 Timers 8/16-bit 1/1 1/1 2/1 1/1 1/1 2/1 SSP ECCP+ EUSART
No Yes No Yes Yes Yes
No No Yes No No Yes
No No No Yes Yes Yes
PIC16F631 Pin Diagram
20-pin PDIP, SOIC, SSOP VDD RA5/T1CKI/OSC1/CLKIN RA4/T1G/OSC2/CLKOUT RA3/MCLR/VPP RC5 RC4/C2OUT RC3/C12IN3RC6 RC7 RB7 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 VSS RA0/C1IN+/ICSPDAT/ULPWU RA1/C12IN0-/ICSPCLK RA2/T0CKI/INT/C1OUT RC0/C2IN+ RC1/C12IN1RC2/C12IN2RB4 RB5 RB6
TABLE 1:
I/O RA0 RA1 RA2 RA3 RA4 RA5 RB4 RB5 RB6 RB7 RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7 -- -- Note 1: Pin 19 18 17 4 3 2 13 12 11 10 16 15 14 7 6 5 8 9 1 20
PIC16F631 PIN SUMMARY
Analog AN0/ULPWU AN1 -- -- -- -- -- -- -- -- AN4 AN5 AN6 AN7 -- -- -- -- -- -- Comparators C1IN+ C12IN0C1OUT -- -- -- -- -- -- -- C2IN+ C12IN1C12IN2C12IN3C2OUT -- -- -- -- -- Timers -- -- T0CKI -- T1G T1CKI -- -- -- -- -- -- -- -- -- -- -- -- -- -- Interrupt IOC IOC IOC/INT IOC IOC IOC IOC IOC IOC IOC -- -- -- -- -- -- -- -- -- -- Pull-up Y Y Y Y(1) Y Y Y Y Y Y -- -- -- -- -- -- -- -- -- -- Basic ICSPDAT ICSPCLK -- MCLR/VPP OSC2/CLKOUT OSC1/CLKIN -- -- -- -- -- -- -- -- -- -- -- -- VDD VSS
Pull-up enabled only with external MCLR configuration.
PIC16F631
DS41262D-page 2
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
PIC16F677 Pin Diagram
20-pin PDIP, SOIC, SSOP VDD RA5/T1CKI/OSC1/CLKIN RA4/AN3/T1G/OSC2/CLKOUT RA3/MCLR/VPP RC5 RC4/C2OUT RC3/AN7C12IN3RC6/AN8/SS RC7/AN9/SDO RB7 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 VSS RA0/AN0/C1IN+/ICSPDAT/ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RC0/AN4/C2IN+ RC1/AN5/C12IN1RC2/AN6/C12IN2RB4/AN10/SDI/SDA RB5/AN11 RB6/SCK/SCL
TABLE 2:
I/O RA0 RA1 RA2 RA3 RA4 RA5 RB4 RB5 RB6 RB7 RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7 -- -- Note 1: Pin 19 18 17 4 3 2 13 12 11 10 16 15 14 7 6 5 8 9 1 20
PIC16F677 PIN SUMMARY
Analog AN0/ULPWU AN1/VREF AN2 -- AN3 -- AN10 AN11 -- -- AN4 AN5 AN6 AN7 -- -- AN8 AN9 -- -- Comparators C1IN+ C12IN0C1OUT -- -- -- -- -- -- -- C2IN+ C12IN1C12IN2C12IN3C2OUT -- -- -- -- -- Timers -- -- T0CKI -- T1G T1CKI -- -- -- -- -- -- -- -- -- -- -- -- -- -- SSP -- -- -- -- -- -- SDI/SDA -- SCL/SCK -- -- -- -- -- -- -- SS SDO -- -- Interrupt IOC IOC IOC/INT IOC IOC IOC IOC IOC IOC IOC -- -- -- -- -- -- -- -- -- -- Pull-up Y Y Y Y(1) Y Y Y Y Y Y -- -- -- -- -- -- -- -- -- -- Basic ICSPDAT ICSPCLK -- MCLR/VPP OSC2/CLKOUT OSC1/CLKIN -- -- -- -- -- -- -- -- -- -- -- -- VDD VSS
Pull-up activated only with external MCLR configuration.
(c) 2007 Microchip Technology Inc.
PIC16F677
DS41262D-page 3
PIC16F631/677/685/687/689/690
PIC16F685 Pin Diagram
20-pin PDIP, SOIC, SSOP VDD RA5/T1CKI/OSC1/CLKIN RA4/AN3/T1G/OSC2/CLKOUT RA3/MCLR/VPP RC5/CCP1/P1A RC4/C2OUT/P1B RC3/AN7/C12IN3-/P1C RC6/AN8 RC7/AN9 RB7 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11
VSS RA0/AN0/C1IN+/ICSPDAT/ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RC0/AN4/C2IN+ RC1/AN5/C12IN1RC2/AN6/C12IN2-/P1D RB4/AN10 RB5/AN11 RB6
TABLE 3:
I/O RA0 RA1 RA2 RA3 RA4 RA5 RB4 RB5 RB6 RB7 RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7 -- -- Note 1: Pin 19 18 17 4 3 2 13 12 11 10 16 15 14 7 6 5 8 9 1 20
PIC16F685 PIN SUMMARY
Analog AN0/ULPWU AN1/VREF AN2 -- AN3 -- AN10 AN11 -- -- AN4 AN5 AN6 AN7 -- -- AN8 AN9 -- -- Comparators C1IN+ C12IN0C1OUT -- -- -- -- -- -- -- C2IN+ C12IN1C12IN2C12IN3C2OUT -- -- -- -- -- Timers -- -- T0CKI -- T1G T1CKI -- -- -- -- -- -- -- -- -- -- -- -- -- -- ECCP -- -- -- -- -- -- -- -- -- -- -- -- P1D P1C P1B CCP1/P1A -- -- -- -- Interrupt IOC IOC IOC/INT IOC IOC IOC IOC IOC IOC IOC -- -- -- -- -- -- -- -- -- -- Pull-up Y Y Y Y(1) Y Y Y Y Y Y -- -- -- -- -- -- -- -- -- -- Basic ICSPDAT ICSPCLK -- MCLR/VPP OSC2/CLKOUT OSC1/CLKIN -- -- -- -- -- -- -- -- -- -- -- -- VDD VSS
Pull-up activated only with external MCLR configuration.
PIC16F685
DS41262D-page 4
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
PIC16F687/689 Pin Diagram
20-pin PDIP, SOIC, SSOP VDD RA5/T1CKI/OSC1/CLKIN RA4/AN3/T1G/OSC2/CLKOUT RA3/MCLR/VPP RC5 RC4/C2OUT RC3/AN7/C12IN3RC6/AN8/SS RC7/AN9/SDO RB7/TX/CK 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 VSS RA0/AN0/C1IN+/ICSPDAT/ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RC0/AN4/C2IN+ RC1/AN5/C12IN1RC2/AN6/C12IN2RB4/AN10/SDI/SDA RB5/AN11/RX/DT RB6/SCK/SCL
TABLE 4:
I/O RA0 RA1 RA2 RA3 RA4 RA5 RB4 RB5 RB6 RB7 RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7 -- -- Pin 19 18 17 4 3 2 13 12 11 10 16 15 14 7 6 5 8 9 1 20
PIC16F687/689 PIN SUMMARY
Analog AN0/ULPWU AN1/VREF AN2 -- AN3 -- AN10 AN11 -- -- AN4 AN5 AN6 AN7 -- -- AN8 AN9 -- -- Comparators C1IN+ C12IN0C1OUT -- -- -- -- -- -- -- C2IN+ C12IN1C12IN2C12IN3C2OUT -- -- -- -- -- Timers -- -- T0CKI -- T1G T1CKI -- -- -- -- -- -- -- -- -- -- -- -- -- -- EUSART -- -- -- -- -- -- -- RX/DT -- TX/CK -- -- -- -- -- -- -- -- -- -- SSP -- -- -- -- -- -- SDI/SDA -- SCL/SCK -- -- -- -- -- -- -- SS SDO -- -- Interrupt Pull-up IOC IOC IOC/INT IOC IOC IOC IOC IOC IOC IOC -- -- -- -- -- -- -- -- -- -- Y Y Y Y(1) Y Y Y Y Y Y -- -- -- -- -- -- -- -- -- -- MCLR/VPP OSC2/CLKOUT OSC1/CLKIN -- -- -- -- -- -- -- -- -- -- -- -- VDD VSS Basic ICSPDAT ICSPCLK
Note 1: Pull-up activated only with external MCLR configuration.
(c) 2007 Microchip Technology Inc.
PIC16F687/689
DS41262D-page 5
PIC16F631/677/685/687/689/690
PIC16F690 Pin Diagram (PDIP, SOIC, SSOP)
20-pin PDIP, SOIC, SSOP VDD RA5/T1CKI/OSC1/CLKIN RA4/AN3/T1G/OSC2/CLKOUT RA3/MCLR/VPP RC5/CCP1/P1A RC4/C2OUT/P1B RC3/AN7/C12IN3-/P1C RC6/AN8/SS RC7/AN9/SDO RB7/TX/CK 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 VSS RA0/AN0/C1IN+/ICSPDAT/ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RC0/AN4/C2IN+ RC1/AN5/C12IN1RC2/AN6/C12IN2-/P1D RB4/AN10/SDI/SDA RB5/AN11/RX/DT RB6/SCK/SCL
TABLE 5:
I/O RA0 RA1 RA2 RA3 RA4 RA5 RB4 RB5 RB6 RB7 RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7 -- -- Pin 19 18 17 4 3 2 13 12 11 10 16 15 14 7 6 5 8 9 1 20
PIC16F690 PIN SUMMARY
Analog AN0/ULPWU AN1/VREF AN2 -- AN3 -- AN10 AN11 -- -- AN4 AN5 AN6 AN7 -- -- AN8 AN9 -- -- Comparators Timers C1IN+ C12IN0C1OUT -- -- -- -- -- -- -- C2IN+ C12IN1C12IN2C12IN3C2OUT -- -- -- -- -- -- -- T0CKI -- T1G T1CKI -- -- -- -- -- -- -- -- -- -- -- -- -- -- ECCP -- -- -- -- -- -- -- -- -- -- -- -- P1D P1C P1B CCP1/P1A -- -- -- -- TX/CK -- -- -- -- -- -- -- -- -- -- EUSART -- -- -- -- -- -- -- RX/DT SSP -- -- -- -- -- -- SDI/SDA -- SCL/SCK -- -- -- -- -- -- -- SS SDO -- -- Interrupt IOC IOC IOC/INT IOC IOC IOC IOC IOC IOC IOC -- -- -- -- -- -- -- -- -- -- Pull-up Y Y Y Y(1) Y Y Y Y Y Y -- -- -- -- -- -- -- -- -- -- MCLR/VPP OSC2/CLKOUT OSC1/CLKIN -- -- -- -- -- -- -- -- -- -- -- -- VDD VSS Basic ICSPDAT ICSPCLK
Note 1: Pull-up activated only with external MCLR configuration.
PIC16F690
DS41262D-page 6
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
PIC16F690 Pin Diagram (QFN)
20-pin QFN
RA0/AN0/C1IN+/ICSPDAT/ULPWU 16 15 14 PIC16F631/677/ 685/687/689/690 13 12 11 10 6 7 8 9 RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
20
19
18
VDD
RA3/MCLR/VPP RC5/CCP1/P1A
(1) (1)
1 2 3 4 5
17
VSS
RA1/AN1/C12IN0-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RC0/AN4/C2IN+ RC1/AN5/C12IN1RC2/AN6/C12IN2-/P1D(1)
RC4/C2OUT/P1B
RC3/AN7/C12IN3-/P1C(1) RC6/AN8/SS
(2)
RC7/AN9/SDO(2)
(3)
RB6/SCK/SCL(2)
RB5/AN11/RX/DT(3)
Note 1: 2: 3:
CCP1/P1A, P1B, P1C and P1D are available on PIC16F685/PIC16F690 only. SS, SDO, SDI/SDA and SCL/SCK are available on PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. RX/DT and TX/CK are available on PIC16F687/PIC16F689/PIC16F690 only.
(c) 2007 Microchip Technology Inc.
RB4/AN10/SDI/SDA(2)
RB7/TX/CK
DS41262D-page 7
PIC16F631/677/685/687/689/690
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 9 2.0 Memory Organization ................................................................................................................................................................. 25 3.0 Oscillator Module (With Fail-Safe Clock Monitor)....................................................................................................................... 47 4.0 I/O Ports ..................................................................................................................................................................................... 59 5.0 Timer0 Module ........................................................................................................................................................................... 81 6.0 Timer1 Module with Gate Control............................................................................................................................................... 84 7.0 Timer2 Module ........................................................................................................................................................................... 91 8.0 Comparator Module.................................................................................................................................................................... 93 9.0 Analog-to-Digital Converter (ADC) Module .............................................................................................................................. 107 10.0 Data EEPROM and Flash Program Memory Control ............................................................................................................... 119 11.0 Enhanced Capture/Compare/PWM Module ............................................................................................................................. 127 12.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 149 13.0 SSP Module Overview ............................................................................................................................................................. 175 14.0 Special Features of the CPU .................................................................................................................................................... 193 15.0 Instruction Set Summary .......................................................................................................................................................... 213 16.0 Development Support............................................................................................................................................................... 223 17.0 Electrical Specifications............................................................................................................................................................ 227 18.0 DC and AC Characteristics Graphs and Tables ....................................................................................................................... 255 19.0 Packaging Information.............................................................................................................................................................. 275 Appendix A: Data Sheet Revision History.......................................................................................................................................... 281 Appendix B: Migrating from other PIC(R) Devices ............................................................................................................................... 281
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@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
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at: http://www.microchip.com You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page. The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
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) When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are using.
Customer Notification System
Register on our web site at www.microchip.com to receive the most current information on all of our products.
DS41262D-page 8
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
1.0 DEVICE OVERVIEW
Block Diagrams and pinout descriptions of the devices are as follows: * * * * * PIC16F631 (Figure 1-1, Table 1-1) PIC16F677 (Figure 1-2, Table 1-2) PIC16F685 (Figure 1-3, Table 1-3) PIC16F687/PIC16F689 (Figure 1-4, Table 1-4) PIC16F690 (Figure 1-5, Table 1-5) The PIC16F631/677/685/687/689/690 devices are covered by this data sheet. They are available in 20-pin PDIP, SOIC, TSSOP and QFN packages.
FIGURE 1-1:
PIC16F631 BLOCK DIAGRAM
INT Configuration 13 Program Counter Flash 1K x 14 Program Memory 8-Level Stack (13-bit) RAM 64 bytes File Registers RAM Addr 9 Addr MUX PORTB RA0 RA1 RA2 RA3 RA4 RA5 Data Bus 8 PORTA
Program 14 Bus
Instruction Reg Direct Addr 7 8 Indirect Addr
FSR Reg STATUS Reg 8 PORTC 3 Power-up Timer Instruction Decode and Control OSC1/CLKI OSC2/CLKO Timing Generation Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset Internal Oscillator Block MCLR VDD ULPWU T0CKI VSS T1G T1CKI 8 W Reg ALU MUX
RB4 RB5 RB6 RB7
RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7
C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT EEDAT 128 Bytes Data EEPROM
Ultra Low-Power Wake-up
Timer0
Timer1
EEADR 8
2 Analog Comparators and Reference
(c) 2007 Microchip Technology Inc.
DS41262D-page 9
PIC16F631/677/685/687/689/690
FIGURE 1-2: PIC16F677 BLOCK DIAGRAM
INT Configuration 13 Program Counter Flash 2K x 14 Program Memory 8-Level Stack (13-bit) RAM 128 bytes File Registers RAM Addr 9 Addr MUX Instruction Reg Direct Addr 7 8 Indirect Addr RB4 RB5 RB6 RB7 PORTB RA0 RA1 RA2 RA3 RA4 RA5 Data Bus 8 PORTA
Program 14 Bus
FSR Reg STATUS Reg 8 PORTC 3 Power-up Timer Instruction Decode and Control OSC1/CLKI OSC2/CLKO Timing Generation Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset Internal Oscillator Block MCLR VDD ULPWU T0CKI VSS T1G T1CKI 8 W Reg ALU MUX
RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7
SDI/ SCK/ SDO SDA SCL SS
Ultra Low-Power Wake-up
Timer0
Timer1
Synchronous Serial Port
AN8 AN9 AN10 AN11 EEDAT 2 Analog Comparators and Reference 8 256 Bytes Data EEPROM EEADR
Analog-To-Digital Converter
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
DS41262D-page 10
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 1-3: PIC16F685 BLOCK DIAGRAM
INT Configuration 13 Program Counter Flash 4K x 14 Program Memory 8-Level Stack (13-bit) RAM 256 bytes File Registers RAM Addr 9 Addr MUX Instruction Reg Direct Addr 7 8 Indirect Addr RB4 RB5 RB6 RB7 PORTB RA0 RA1 RA2 RA3 RA4 RA5 Data Bus 8 PORTA
Program 14 Bus
FSR Reg STATUS Reg 8 PORTC 3 Power-up Timer Instruction Decode and Control OSC1/CLKI OSC2/CLKO Timing Generation Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset Internal Oscillator Block MCLR VDD ULPWU T0CKI VSS T1G T1CKI 8 W Reg ALU MUX
RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7
CCP1/ P1A P1B P1C P1D
Ultra Low-Power Wake-up
Timer0
Timer1
Timer2
ECCP+
AN8 AN9 AN10 AN11 EEDAT 2 Analog Comparators and Reference 8 256 Bytes Data EEPROM EEADR
Analog-To-Digital Converter
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
(c) 2007 Microchip Technology Inc.
DS41262D-page 11
PIC16F631/677/685/687/689/690
FIGURE 1-4: PIC16F687/PIC16F689 BLOCK DIAGRAM
INT Configuration 13 Program Counter Flash 2K(1)/4K x 14 Program Memory 8-Level Stack (13-bit) RAM 128(1)/256 bytes File Registers RAM Addr 9 Addr MUX Instruction Reg Direct Addr 7 8 Indirect Addr RB4 RB5 RB6 RB7 PORTB RA0 RA1 RA2 RA3 RA4 RA5 Data Bus 8 PORTA
Program 14 Bus
FSR Reg STATUS Reg 8 PORTC 3 Power-up Timer Instruction Decode and Control OSC1/CLKI OSC2/CLKO Timing Generation Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset Internal Oscillator Block MCLR VDD ULPWU T0CKI VSS T1G T1CKI TX/CK RX/DT 8 W Reg ALU MUX
RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7
SDI/ SCK/ SDO SDA SCL SS
Ultra Low-Power Wake-up
Timer0
Timer1
EUSART
Synchronous Serial Port
AN8 AN9 AN10 AN11 EEDAT 2 Analog Comparators and Reference 8 256 Bytes Data EEPROM EEADR
Analog-To-Digital Converter
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT Note 1: PIC16F687 only.
DS41262D-page 12
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 1-5: PIC16F690 BLOCK DIAGRAM
INT Configuration 13 Program Counter Flash 4k x 14 Program Memory 8-Level Stack (13-bit) RAM 256 bytes File Registers RAM Addr 9 Addr MUX Instruction Reg Direct Addr 7 8 Indirect Addr RB4 RB5 RB6 RB7 PORTB RA0 RA1 RA2 RA3 RA4 RA5 Data Bus 8 PORTA
Program 14 Bus
FSR Reg STATUS Reg 8 PORTC 3 Power-up Timer Instruction Decode and Control OSC1/CLKI OSC2/CLKO Timing Generation Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset Internal Oscillator Block MCLR VDD ULPWU T0CKI T1G T1CKI VSS TX/CK RX/DT CCP1/ P1A 8 W Reg ALU MUX
RC0 RC1 RC2 RC3 RC4 RC5 RC6 RC7
P1B P1C P1D
SDI/ SCK/ SDO SDA SCL SS
Ultra Low-Power Wake-up
Timer0
Timer1
Timer2
EUSART
ECCP+
Synchronous Serial Port
AN8 AN9 AN10 AN11 EEDAT 2 Analog Comparators and Reference 8 256 Bytes Data EEPROM EEADR
Analog-To-Digital Converter
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
(c) 2007 Microchip Technology Inc.
DS41262D-page 13
PIC16F631/677/685/687/689/690
TABLE 1-1: PINOUT DESCRIPTION - PIC16F631
Function RA0 C1IN+ ICSPDAT ULPWU RA1/C12IN0-/ICSPCLK RA1 C12IN0ICSPCLK RA2/T0CKI/INT/C1OUT RA2 T0CKI INT C1OUT RA3/MCLR/VPP RA3 MCLR VPP RA4/T1G/OSC2/CLKOUT RA4 T1G OSC2 CLKOUT RA5/T1CKI/OSC1/CLKIN RA5 T1CKI OSC1 CLKIN RB4 RB5 RB6 RB7 RC0/C2IN+ RC1/C12IN1RC2/C12IN2RC3/C12IN3RC4/C2OUT RC5 Legend: RB4 RB5 RB6 RB7 RC0 C2IN+ RC1 C12IN1RC2 C12IN2RC3 C12IN3RC4 C2OUT RC5 AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL AN ST AN TTL AN ST ST ST ST -- TTL ST HV TTL ST -- -- TTL ST XTAL ST TTL TTL TTL TTL ST AN ST AN ST AN ST AN ST -- ST Output Type Description Name RA0/C1IN+/ICSPDAT/ULPWU
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- Comparator C1 non-inverting input. Ultra Low-Power Wake-up input. CMOS ICSPTM Data I/O. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- Comparator C1 or C2 inverting input. ICSPTM clock.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- -- -- -- Timer0 clock input. External interrupt pin. General purpose input. Individually controlled interrupt-onchange. Master Clear with internal pull-up. Programming voltage.
CMOS Comparator C1 output.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- XTAL Timer1 gate input. Crystal/Resonator.
CMOS FOSC/4 output. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- -- Timer1 clock input. Crystal/Resonator. External clock input/RC oscillator connection.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS General purpose I/O. -- -- -- -- Comparator C2 non-inverting input. Comparator C1 or C2 inverting input. Comparator C1 or C2 inverting input. Comparator C1 or C2 inverting input. CMOS General purpose I/O. CMOS General purpose I/O. CMOS General purpose I/O. CMOS General purpose I/O. CMOS Comparator C2 output. CMOS General purpose I/O.
CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
DS41262D-page 14
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 1-1: PINOUT DESCRIPTION - PIC16F631 (CONTINUED)
Function RC6 RC7 VSS VDD AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type ST ST Power Power Output Type CMOS General purpose I/O. CMOS General purpose I/O. -- -- Ground reference. Positive supply. Description Name RC6 RC7 VSS VDD Legend:
CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
(c) 2007 Microchip Technology Inc.
DS41262D-page 15
PIC16F631/677/685/687/689/690
TABLE 1-2: PINOUT DESCRIPTION - PIC16F677
Function RA0 AN0 C1IN+ ICSPDAT ULPWU RA1/AN1/C12IN0-/VREF/ ICSPCLK RA1 AN1 C12IN0VREF ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RA2 AN2 T0CKI INT C1OUT RA3/MCLR/VPP RA3 MCLR VPP RA4/AN3/T1G/OSC2/CLKOUT RA4 AN3 T1G OSC2 CLKOUT RA5/T1CKI/OSC1/CLKIN RA5 T1CKI OSC1 CLKIN RB4/AN10/SDI/SDA RB4 AN10 SDI SDA RB5/AN11 RB5 AN11 RB6/SCK/SCL RB6 SCK SCL Legend: AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL AN AN ST AN TTL AN AN AN ST ST AN ST ST -- TTL ST HV TTL AN ST -- -- TTL ST XTAL ST TTL AN ST ST TTL AN TTL ST ST Output Type Description
Name RA0/AN0/C1IN+/ICSPDAT/ ULPWU
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- -- A/D Channel 0 input. Comparator C1 non-inverting input. Ultra Low-Power Wake-up input.
CMOS ICSPTM Data I/O. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- -- -- A/D Channel 1 input. Comparator C1 or C2 inverting input. External Voltage Reference for A/D. ICSPTM clock.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- -- -- -- -- A/D Channel 2 input. Timer0 clock input. External interrupt pin. General purpose input. Individually controlled interrupt-onchange. Master Clear with internal pull-up. Programming voltage.
CMOS Comparator C1 output.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- XTAL A/D Channel 3 input. Timer1 gate input. Crystal/Resonator.
CMOS FOSC/4 output. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- -- Timer1 clock input. Crystal/Resonator. External clock input/RC oscillator connection.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- -- OD A/D Channel 10 input. SPI data input. I2CTM data input/output.
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. -- A/D Channel 11 input. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS SPI clock. OD I2CTM clock.
CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
DS41262D-page 16
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 1-2: PINOUT DESCRIPTION - PIC16F677 (CONTINUED)
Function RB7 RC0 AN4 C2IN+ RC1/AN5/C12IN1RC1 AN5 C12IN1RC2/AN6/C12IN2RC2 AN6 C12IN2RC3/AN7/C12IN3RC3 AN7 C12IN3RC4/C2OUT RC5 RC6/AN8/SS RC4 C2OUT RC5 RC6 AN8 SS RC7/AN9/SDO RC7 AN9 SDO VSS VDD Legend: VSS VDD AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL ST AN AN ST AN AN ST AN AN ST AN AN ST -- ST ST AN ST ST AN -- Power Power Output Type Description Name RB7 RC0/AN4/C2IN+
CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS General purpose I/O. -- -- -- -- -- -- -- -- A/D Channel 4 input. Comparator C2 non-inverting input. A/D Channel 5 input. Comparator C1 or C2 inverting input. A/D Channel 6 input. Comparator C1 or C2 inverting input. A/D Channel 7 input. Comparator C1 or C2 inverting input.
CMOS General purpose I/O.
CMOS General purpose I/O.
CMOS General purpose I/O.
CMOS General purpose I/O. CMOS Comparator C2 output. CMOS General purpose I/O. CMOS General purpose I/O. -- -- -- -- -- A/D Channel 8 input. Slave Select input. A/D Channel 9 input. Ground reference. Positive supply.
CMOS General purpose I/O. CMOS SPI data output.
CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
(c) 2007 Microchip Technology Inc.
DS41262D-page 17
PIC16F631/677/685/687/689/690
TABLE 1-3: PINOUT DESCRIPTION - PIC16F685
Name RA0/AN0/C1IN+/ICSPDAT/ ULPWU Function RA0 AN0 C1IN+ ICSPDAT ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA1 AN1 C12IN0VREF ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RA2 AN2 T0CKI INT C1OUT RA3/MCLR/VPP RA3 MCLR VPP RA4/AN3/T1G/OSC2/CLKOUT RA4 AN3 T1G OSC2 CLKOUT RA5/T1CKI/OSC1/CLKIN RA5 T1CKI OSC1 CLKIN RB4/AN10 RB4 AN10 RB5/AN11 RB5 AN11 RB6 RB7 RC0/AN4/C2IN+ RB6 RB7 RC0 AN4 C2IN+ Legend: AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL AN AN TTL AN TTL AN AN AN ST ST AN ST ST -- TTL ST HV TTL AN ST -- -- TTL ST XTAL ST TTL AN TTL AN TTL TTL ST AN AN Output Type Description
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- A/D Channel 0 input. Comparator C1 positive input. Ultra Low-Power Wake-up input.
CMOS ICSPTM Data I/O. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- -- A/D Channel 1 input. Comparator C1 or C2 negative input. External Voltage Reference for A/D. ICSPTM clock.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- -- -- -- A/D Channel 2 input. Timer0 clock input.
External interrupt pin.
General purpose input. Individually controlled interrupt-onchange. Master Clear with internal pull-up. Programming voltage.
CMOS Comparator C1 output.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- XTAL A/D Channel 3 input. Timer1 gate input. Crystal/Resonator.
CMOS FOSC/4 output. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- Timer1 clock input. Crystal/Resonator. External clock input/RC oscillator connection.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- A/D Channel 10 input. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- A/D Channel 11 input. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. CMOS General purpose I/O. -- -- A/D Channel 4 input. Comparator C2 positive input.
CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
DS41262D-page 18
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 1-3: PINOUT DESCRIPTION - PIC16F685 (CONTINUED)
Name RC1/AN5/C12IN1Function RC1 AN5 C12IN1RC2/AN6/C12IN2-/P1D RC2 AN6 C12IN2P1D RC3/AN7/C12IN3-/P1C RC3 AN7 C12IN3P1C RC4/C2OUT/P1B RC4 C2OUT P1B RC5/CCP1/P1A RC5 CCP1 P1A RC6/AN8 RC7/AN9 VSS VDD Legend: RC6 AN8 RC7 AN9 VSS VDD AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type ST AN AN ST AN AN -- ST AN AN -- ST -- -- ST ST ST ST AN ST AN Power Power Output Type CMOS General purpose I/O. -- -- -- -- A/D Channel 5 input. Comparator C1 or C2 negative input. A/D Channel 6 input. Comparator C1 or C2 negative input. Description
CMOS General purpose I/O.
CMOS PWM output. CMOS General purpose I/O. -- -- A/D Channel 7 input. Comparator C1 or C2 negative input.
CMOS PWM output. CMOS General purpose I/O. CMOS Comparator C2 output. CMOS PWM output. CMOS General purpose I/O. CMOS Capture/Compare input. CMOS PWM output. CMOS General purpose I/O. -- -- -- -- A/D Channel 8 input. A/D Channel 9 input. Ground reference. Positive supply. CMOS General purpose I/O.
CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
(c) 2007 Microchip Technology Inc.
DS41262D-page 19
PIC16F631/677/685/687/689/690
TABLE 1-4: PINOUT DESCRIPTION - PIC16F687/PIC16F689
Name RA0/AN0/C1IN+/ICSPDAT/ ULPWU Function RA0 AN0 C1IN+ ICSPDAT ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA1 AN1 C12IN0VREF ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RA2 AN2 T0CKI INT C1OUT RA3/MCLR/VPP RA3 MCLR VPP RA4/AN3/T1G/OSC2/CLKOUT RA4 AN3 T1G OSC2 CLKOUT RA5/T1CKI/OSC1/CLKIN RA5 T1CKI OSC1 CLKIN RB4/AN10/SDI/SDA RB4 AN10 SDI SDA RB5/AN11/RX/DT RB5 AN11 RX DT Legend: AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL AN AN TTL AN TTL AN AN AN ST ST AN ST ST -- TTL ST HV TTL AN ST -- -- TTL ST XTAL ST TTL AN ST ST TTL AN ST ST Output Type Description
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- A/D Channel 0 input. Comparator C1 positive input. Ultra Low-Power Wake-up input.
CMOS ICSPTM Data I/O. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- -- A/D Channel 1 input. Comparator C1 or C2 negative input. External Voltage Reference for A/D. ICSPTM clock.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- -- -- -- A/D Channel 2 input. Timer0 clock input. External Interrupt. General purpose input. Individually controlled interrupt-on-change. Master Clear with internal pull-up. Programming voltage.
CMOS Comparator C1 output.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- XTAL A/D Channel 3 input. Timer1 gate input. Crystal/Resonator.
CMOS FOSC/4 output. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- Timer1 clock input. Crystal/Resonator. External clock input/RC oscillator connection.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- OD A/D Channel 10 input. SPI data input. I2CTM data input/output.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- A/D Channel 11 input. EUSART asynchronous input.
CMOS EUSART synchronous data.
CMOS = CMOS compatible input or output OD = Open Drain ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
DS41262D-page 20
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 1-4: PINOUT DESCRIPTION - PIC16F687/PIC16F689 (CONTINUED)
Name RB6/SCK/SCL Function RB6 SCK SCL RB7/TX/CK RB7 TX CK RC0/AN4/C2IN+ RC0 AN4 C2IN+ RC1/AN5/C12IN1RC1 AN5 C12IN1RC2/AN6/C12IN2RC2 AN6 C12IN2RC3/AN7/C12IN3RC3 AN7 C12IN3RC4/C2OUT RC5 RC6/AN8/SS RC4 C2OUT RC5 RC6 AN8 SS RC7/AN9/SDO RC7 AN9 SDO VSS VDD Legend: VSS VDD AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL ST ST TTL -- ST ST AN AN ST AN AN ST AN AN ST AN AN ST -- ST ST AN ST ST AN -- Power Power Output Type Description
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. CMOS SPI clock. OD I2CTM clock. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. CMOS EUSART asynchronous output. CMOS EUSART synchronous clock. CMOS General purpose I/O. -- -- -- -- -- -- -- -- A/D Channel 4 input. Comparator C2 positive input. A/D Channel 5 input. Comparator C1 or C2 negative input. A/D Channel 6 input. Comparator C1 or C2 negative input. A/D Channel 7 input. Comparator C1 or C2 negative input.
CMOS General purpose I/O.
CMOS General purpose I/O.
CMOS General purpose I/O.
CMOS General purpose I/O. CMOS Comparator C2 output. CMOS General purpose I/O. CMOS General purpose I/O. -- -- -- -- -- A/D Channel 8 input. Slave Select input. A/D Channel 9 input. Ground reference. Positive supply.
CMOS General purpose I/O. CMOS SPI data output.
CMOS = CMOS compatible input or output OD = Open Drain ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
(c) 2007 Microchip Technology Inc.
DS41262D-page 21
PIC16F631/677/685/687/689/690
TABLE 1-5: PINOUT DESCRIPTION - PIC16F690
Name RA0/AN0/C1IN+/ICSPDAT/ ULPWU Function RA0 AN0 C1IN+ ICSPDAT ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA1 AN1 C12IN0VREF ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RA2 AN2 T0CKI INT C1OUT RA3/MCLR/VPP RA3 MCLR VPP RA4/AN3/T1G/OSC2/CLKOUT RA4 AN3 T1G OSC2 CLKOUT RA5/T1CKI/OSC1/CLKIN RA5 T1CKI OSC1 CLKIN RB4/AN10/SDI/SDA RB4 AN10 SDI SDA RB5/AN11/RX/DT RB5 AN11 RX DT Legend: AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL AN AN TTL AN TTL AN AN AN ST ST AN ST ST -- TTL ST HV TTL AN ST -- -- TTL ST XTAL ST TTL AN ST ST TTL AN ST ST Output Type Description
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- A/D Channel 0 input. Comparator C1 positive input. Ultra Low-Power Wake-up input.
CMOS ICSPTM Data I/O. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- -- A/D Channel 1 input. Comparator C1 or C2 negative input. External Voltage Reference for A/D. ICSPTM clock.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- -- -- -- A/D Channel 2 input. Timer0 clock input. External interrupt. General purpose input. Individually controlled interrupt-onchange. Master Clear with internal pull-up. Programming voltage.
CMOS Comparator C1 output.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- XTAL A/D Channel 3 input. Timer1 gate input. Crystal/Resonator.
CMOS FOSC/4 output. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- -- Timer1 clock input. Crystal/Resonator. External clock input/RC oscillator connection.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- OD A/D Channel 10 input. SPI data input. I2CTM data input/output.
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. -- -- A/D Channel 11 input. EUSART asynchronous input.
CMOS EUSART synchronous data.
CMOS = CMOS compatible input or output OD = Open Drain ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
DS41262D-page 22
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 1-5: PINOUT DESCRIPTION - PIC16F690 (CONTINUED)
Name RB6/SCK/SCL Function RB6 SCK SCL RB7/TX/CK RB7 TX CK RC0/AN4/C2IN+ RC0 AN4 C2IN+ RC1/AN5/C12IN1RC1 AN5 C12IN1RC2/AN6/C12IN2-/P1D RC2 AN6 C12IN2P1D RC3/AN7/C12IN3-/P1C RC3 AN7 C12IN3P1C RC4/C2OUT/P1B RC4 C2OUT P1B RC5/CCP1/P1A RC5 CCP1 P1A RC6/AN8/SS RC6 AN8 SS RC7/AN9/SDO RC7 AN9 SDO VSS VDD Legend: VSS VDD AN = Analog input or output TTL = TTL compatible input HV = High Voltage Input Type TTL ST ST TTL -- ST ST AN AN ST AN AN ST AN AN -- ST AN AN -- ST -- -- ST ST ST ST AN ST ST AN -- Power Power Output Type Description
CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. CMOS SPI clock. OD I2CTM clock. CMOS General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up. CMOS EUSART asynchronous output. CMOS EUSART synchronous clock. CMOS General purpose I/O. -- -- -- -- -- -- A/D Channel 4 input. Comparator C2 positive input. A/D Channel 5 input. Comparator C1 or C2 negative input. A/D Channel 6 input. Comparator C1 or C2 negative input.
CMOS General purpose I/O.
CMOS General purpose I/O.
CMOS PWM output. CMOS General purpose I/O. -- -- A/D Channel 7 input. Comparator C1 or C2 negative input.
CMOS PWM output. CMOS General purpose I/O. CMOS Comparator C2 output. CMOS PWM output. CMOS General purpose I/O. CMOS Capture/Compare input. CMOS PWM output. CMOS General purpose I/O. -- -- -- -- -- A/D Channel 8 input. Slave Select input. A/D Channel 9 input. Ground reference. Positive supply.
CMOS General purpose I/O. CMOS SPI data output.
CMOS = CMOS compatible input or output OD = Open Drain ST = Schmitt Trigger input with CMOS levels XTAL = Crystal
(c) 2007 Microchip Technology Inc.
DS41262D-page 23
PIC16F631/677/685/687/689/690
NOTES:
DS41262D-page 24
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
2.0
2.1
MEMORY ORGANIZATION
Program Memory Organization
FIGURE 2-2:
PROGRAM MEMORY MAP AND STACK FOR THE PIC16F685/689/690
PC<12:0>
The PIC16F631/677/685/687/689/690 has a 13-bit program counter capable of addressing an 8K x 14 program memory space. Only the first 1K x 14 (0000h-03FFh) is physically implemented for the PIC16F631, the first 2K x 14 (0000h-07FFh) for the PIC16F677/PIC16F687, and the first 4K x 14 (0000h-0FFFh) for the PIC16F685/PIC16F689/ PIC16F690. Accessing a location above these boundaries will cause a wraparound. The Reset vector is at 0000h and the interrupt vector is at 0004h (see Figures 2-1 through 2-3).
CALL, RETURN RETFIE, RETLW
13
Stack Level 1 Stack Level 2
Stack Level 8 Reset Vector
0000h
FIGURE 2-1:
PROGRAM MEMORY MAP AND STACK FOR THE PIC16F631
PC<12:0>
Interrupt Vector
0004h 0005h
On-chip Program Memory 13
CALL, RETURN RETFIE, RETLW
0FFFh 1000h
Stack Level 1 Stack Level 2
Access 0-FFFh 1FFFh
Stack Level 8 Reset Vector
0000h
Interrupt Vector
0004h 0005h
On-chip Program Memory 03FFh 0400h Access 0-3FFh 1FFFh
(c) 2007 Microchip Technology Inc.
DS41262D-page 25
PIC16F631/677/685/687/689/690
FIGURE 2-3: PROGRAM MEMORY MAP AND STACK FOR THE PIC16F677/PIC16F687
PC<12:0> CALL, RETURN RETFIE, RETLW 13
2.2
Data Memory Organization
Stack Level 1 Stack Level 2
Stack Level 8 Reset Vector
0000h
The data memory (see Figures 2-6 through 2-8) is partitioned into four banks which contain the General Purpose Registers (GPR) and the Special Function Registers (SFR). The Special Function Registers are located in the first 32 locations of each bank. The General Purpose Registers, implemented as static RAM, are located in the last 96 locations of each Bank. Register locations F0h-FFh in Bank 1, 170h-17Fh in Bank 2 and 1F0h-1FFh in Bank 3 point to addresses 70h-7Fh in Bank 0. The actual number of General Purpose Resisters (GPR) in each Bank depends on the device. Details are shown in Figures 2-4 through 2-8. All other RAM is unimplemented and returns `0' when read. RP<1:0> of the STATUS register are the bank select bits: RP1 0 0 RP0 0 1 0 1 Bank 0 is selected Bank 1 is selected Bank 2 is selected Bank 3 is selected
Interrupt Vector
0004h 0005h
On-chip Program Memory 07FFh 0800h Access 0-7FFh 1FFFh
1 1
2.2.1
GENERAL PURPOSE REGISTER FILE
The register file is organized as 128 x 8 in the PIC16F687 and 256 x 8 in the PIC16F685/PIC16F689/PIC16F690. Each register is accessed, either directly or indirectly, through the File Select Register (FSR) (see Section 2.4 "Indirect Addressing, INDF and FSR Registers").
2.2.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers are registers used by the CPU and peripheral functions for controlling the desired operation of the device (see Tables 2-1 through 2-4). These registers are static RAM. The special registers can be classified into two sets: core and peripheral. The Special Function Registers associated with the "core" are described in this section. Registers related to the operation of peripheral features are described in the section of that peripheral feature.
DS41262D-page 26
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 2-4: PIC16F631 SPECIAL FUNCTION REGISTERS
File Address Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 1Dh 1Eh 1Fh 20h 3Fh 40h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8Ah 8Bh 8Ch 8Dh 8Eh 8Fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Ch 9Dh 9Eh 9Fh A0h Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC File Address 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10Ah 10Bh 10Ch 10Dh 10Eh 10Fh 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh 120h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18Ah 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 19Dh 19Eh 19Fh 1A0h
PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON
PCLATH INTCON PIE1 PIE2 PCON OSCCON OSCTUNE
PCLATH INTCON EEDAT EEADR
PCLATH INTCON EECON1 EECON2(1)
WPUA IOCA WDTCON
WPUB IOCB VRCON CM1CON0 CM2CON0 CM2CON1
ANSEL
SRCON
General Purpose Registers 64 Bytes Bank 0
6Fh 70h 7Fh
accesses 70h-7Fh Bank 1
EFh F0h FFh
accesses 70h-7Fh Bank 2
16Fh 170h 17Fh
accesses 70h-7Fh Bank 3
1EFh 1F0h 1FFh
Note 1:
Unimplemented data memory locations, read as `0'. Not a physical register.
(c) 2007 Microchip Technology Inc.
DS41262D-page 27
PIC16F631/677/685/687/689/690
FIGURE 2-5: PIC16F677 SPECIAL FUNCTION REGISTERS
File Address Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 1Dh 1Eh 1Fh 20h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8Ah 8Bh 8Ch 8Dh 8Eh 8Fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Ch 9Dh 9Eh 9Fh A0h Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC File Address 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10Ah 10Bh 10Ch 10Dh 10Eh 10Fh 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh 120h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18Ah 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 19Dh 19Eh 19Fh 1A0h
PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON
PCLATH INTCON PIE1 PIE2 PCON OSCCON OSCTUNE
PCLATH INTCON EEDAT EEADR
PCLATH INTCON EECON1 EECON2(1)
SSPBUF SSPCON
SSPADD(2) SSPSTAT WPUA IOCA WDTCON
WPUB IOCB VRCON CM1CON0 CM2CON0 CM2CON1
ADRESH ADCON0
ADRESL ADCON1 General Purpose Register 32 Bytes
ANSEL ANSELH
SRCON
General Purpose Register 96 Bytes 7Fh Bank 0
BFh C0h EFh F0h FFh 16Fh 170h 17Fh 1EFh 1F0h 1FFh
accesses 70h-7Fh Bank 1
accesses 70h-7Fh Bank 2
accesses 70h-7Fh Bank 3
Note 1: 2:
Unimplemented data memory locations, read as `0'. Not a physical register. Address 93h also accesses the SSP Mask (SSPMSK) register under certain conditions. See Registers 13-2 and 13-3 for more details.
DS41262D-page 28
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 2-6: PIC16F685 SPECIAL FUNCTION REGISTERS
File Address Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 1Dh 1Eh 1Fh 20h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8Ah 8Bh 8Ch 8Dh 8Eh 8Fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Ch 9Dh 9Eh 9Fh A0h Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC File Address 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10Ah 10Bh 10Ch 10Dh 10Eh 10Fh 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh 120h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18Ah 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 19Dh 19Eh 19Fh 1A0h
PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON TMR2 T2CON
PCLATH INTCON PIE1 PIE2 PCON OSCCON OSCTUNE PR2
PCLATH INTCON EEDAT EEADR EEDATH EEADRH
PCLATH INTCON EECON1 EECON2(1)
CCPR1L CCPR1H CCP1CON
WPUA IOCA WDTCON
WPUB IOCB VRCON CM1CON0 CM2CON0 CM2CON1
PWM1CON ECCPAS ADRESH ADCON0
ADRESL ADCON1
ANSEL ANSELH
PSTRCON SRCON
General Purpose Register 96 Bytes 7Fh Bank 0
General Purpose Register 80 Bytes accesses 70h-7Fh Bank 1 EFh F0h FFh
General Purpose Register 80 Bytes accesses 70h-7Fh Bank 2 16Fh 170h 17Fh accesses 70h-7Fh Bank 3 1F0h 1FFh
Note 1:
Unimplemented data memory locations, read as `0'. Not a physical register.
(c) 2007 Microchip Technology Inc.
DS41262D-page 29
PIC16F631/677/685/687/689/690
FIGURE 2-7: PIC16F687/PIC16F689 SPECIAL FUNCTION REGISTERS
File Address Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 1Dh 1Eh 1Fh 20h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8Ah 8Bh 8Ch 8Dh 8Eh 8Fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Ch 9Dh 9Eh 9Fh A0h Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC File Address 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10Ah 10Bh 10Ch 10Dh 10Eh 10Fh 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh 120h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18Ah 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 19Dh 19Eh 19Fh 1A0h
PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON
PCLATH INTCON PIE1 PIE2 PCON OSCCON OSCTUNE
PCLATH INTCON EEDAT EEADR EEDATH(3) EEADRH(3)
PCLATH INTCON EECON1 EECON2(1)
SSPBUF SSPCON
RCSTA TXREG RCREG
SSPADD(2) SSPSTAT WPUA IOCA WDTCON TXSTA SPBRG SPBRGH BAUDCTL
WPUB IOCB VRCON CM1CON0 CM2CON0 CM2CON1
ADRESH ADCON0
ADRESL ADCON1 General Purpose Register 32 Bytes 48 Bytes (PIC16F689 only) accesses 70h-7Fh Bank 1
ANSEL ANSELH General Purpose Register 80 Bytes (PIC16F689 only) accesses 70h-7Fh Bank 2
SRCON
General Purpose Register 96 Bytes 7Fh Bank 0 Note 1: 2: 3:
BFh C0h EFh F0h FFh
170h 17Fh
accesses 70h-7Fh Bank 3
1F0h 1FFh
Unimplemented data memory locations, read as `0'. Not a physical register. Address 93h also accesses the SSP Mask (SSPMSK) register under certain conditions. See Registers 13-2 and 13-3 for more details. PIC16F689 only.
DS41262D-page 30
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 2-8: PIC16F690 SPECIAL FUNCTION REGISTERS
File Address Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 1Dh 1Eh 1Fh 20h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8Ah 8Bh 8Ch 8Dh 8Eh 8Fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Ch 9Dh 9Eh 9Fh A0h Indirect addr. (1) TMR0 PCL STATUS FSR PORTA PORTB PORTC File Address 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10Ah 10Bh 10Ch 10Dh 10Eh 10Fh 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh 120h Indirect addr. (1) OPTION_REG PCL STATUS FSR TRISA TRISB TRISC File Address 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18Ah 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 19Dh 19Eh 19Fh 1A0h
PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON TMR2 T2CON SSPBUF SSPCON CCPR1L CCPR1H CCP1CON RCSTA TXREG RCREG PWM1CON ECCPAS ADRESH ADCON0
PCLATH INTCON PIE1 PIE2 PCON OSCCON OSCTUNE PR2 SSPADD(2) SSPSTAT WPUA IOCA WDTCON TXSTA SPBRG SPBRGH BAUDCTL
PCLATH INTCON EEDAT EEADR EEDATH EEADRH
PCLATH INTCON EECON1 EECON2(1)
WPUB IOCB VRCON CM1CON0 CM2CON0 CM2CON1
ADRESL ADCON1
ANSEL ANSELH
PSTRCON SRCON
General Purpose Register 96 Bytes 7Fh Bank 0
General Purpose Register 80 Bytes accesses 70h-7Fh Bank 1 EFh F0h FFh
General Purpose Register 80 Bytes accesses 70h-7Fh Bank 2 16Fh 170h 17Fh accesses 70h-7Fh Bank 3 1F0h 1FFh
Note 1: 2:
Unimplemented data memory locations, read as `0'. Not a physical register. Address 93h also accesses the SSP Mask (SSPMSK) register under certain conditions. See Registers 13-2 and 13-3 for more details.
(c) 2007 Microchip Technology Inc.
DS41262D-page 31
PIC16F631/677/685/687/689/690
TABLE 2-1:
Addr Bank 0 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch 1Dh 1Eh 1Fh INDF TMR0 PCL STATUS FSR PORTA(7) PORTB(7) PORTC(7) -- -- PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON TMR2(3) T2CON(3) SSPBUF(5) SSPCON
(5, 6)
PIC16F631/677/685/687/689/690 SPECIAL FUNCTION REGISTERS SUMMARY BANK 0
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Page
Name
Addressing this location uses contents of FSR to address data memory (not a physical register) Timer0 Module Register Program Counter's (PC) Least Significant Byte IRP RP1 RP0 TO PD Z DC C
xxxx xxxx xxxx xxxx 0000 0000 0001 1xxx xxxx xxxx
44,201 81,201 44,201 36,201 44,201 59,201 69,201 76,201 -- -- 44,201 38,201 41,201 42,201 86,201 86,201 88,201 91,201 92,201 178,201 177,201 128,201 128,201 127,201 159,201 151 154 -- 144,201 141,201 115,201 113,201
Indirect Data Memory Address Pointer -- RB7 RC7 -- RB6 RC6 RA5 RB5 RC5 RA4 RB4 RC4 RA3 -- RC3 RA2 -- RC2 RA1 -- RC1 RA0 -- RC0
--xx xxxx xxxx ---xxxx xxxx -- --
Unimplemented Unimplemented -- GIE -- OSFIF -- PEIE ADIF
(4)
-- T0IE RCIF
(2)
Write Buffer for upper 5 bits of Program Counter INTE TXIF
(2)
---0 0000 RABIF(1) 0000 000x -000 0000 0000 ---xxxx xxxx xxxx xxxx
RABIE SSPIF --
(5)
T0IF CCP1IF --
(3)
INTF TMR2IF --
(3)
TMR1IF --
C2IF
C1IF
EEIF
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 T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS
TMR1ON 0000 0000 0000 0000
Timer2 Module Register -- TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1
T2CKPS0 -000 0000 xxxx xxxx
Synchronous Serial Port Receive Buffer/Transmit Register WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0
0000 0000 xxxx xxxx xxxx xxxx
CCPR1L(3) CCPR1H(3) CCP1CON(3) RCSTA
(2)
Capture/Compare/PWM Register 1 (LSB) Capture/Compare/PWM Register 1 (MSB) P1M1 SPEN P1M0 RX9 DC1B1 SREN DC1B0 CREN CCP1M3 ADDEN CCP1M2 FERR CCP1M1 OERR CCP1M0 RX9D
0000 0000 0000 000x 0000 0000 0000 0000 --
TXREG(2) RCREG(2) -- PWM1CON(3) ECCPAS(3) ADRESH(4) ADCON0(4)
EUSART Transmit Data Register EUSART Receive Data Register Unimplemented PRSEN PDC6 PDC5 ECCPAS1 PDC4 ECCPAS0 PDC3 PSSAC1 PDC2 PSSAC0 PDC1 PSSBD1 PDC0 PSSBD0
0000 0000 0000 0000 xxxx xxxx
ECCPASE ECCPAS2
A/D Result Register High Byte ADFM VCFG CHS3 CHS2 CHS1 CHS0 GO/DONE ADON
0000 0000
Legend: Note 1: 2: 3: 4: 5: 6: 7:
- = Unimplemented locations read as `0', u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented MCLR and WDT Reset do not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the mismatch exists. PIC16F687/PIC16F689/PIC16F690 only. PIC16F685/PIC16F690 only. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only. PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. When SSPCON register bits SSPM<3:0> = 1001, any reads or writes to the SSPADD SFR address are accessed through the SSPMSK register. See Registers 13-2 and 13-3 for more detail. Port pins with analog functions controlled by the ANSEL and ANSELH registers will read `0' immediately after a Reset even though the data latches are either undefined (POR) or unchanged (other Resets).
DS41262D-page 32
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 2-2:
Addr Bank 1 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8Ah 8Bh 8Ch 8Dh 8Eh 8Fh 90h 91h 92h 93h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Ch 9Dh 9Eh 9Fh INDF OPTION_REG PCL STATUS FSR TRISA TRISB TRISC -- -- PCLATH INTCON PIE1 PIE2 PCON OSCCON OSCTUNE -- PR2(3) SSPADD(5, 7) SSPMSK
(5, 7)
PIC16F631/677/685/687/689/690 SPECIAL FUNCTION REGISTERS SUMMARY BANK 1
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Page
Name
Addressing this location uses contents of FSR to address data memory (not a physical register) RABPU INTEDG T0CS T0SE PSA PS2 PS1 PS0
xxxx xxxx 1111 1111 0000 0000
44,201 37,201 44,201 36,201 44,201 59,201 70,202 76,201 -- -- 44,201 38,201 39,202 40,202 43,202 48,202 52,202 -- 91,202 184,202 187,202 176,202 62,202 62,202 209,202 158,202 161,202 161,202 160,202 -- -- 115,202 114,202
Program Counter's (PC) Least Significant Byte IRP RP1 RP0 TO PD Z DC C
0001 1xxx xxxx xxxx
Indirect Data Memory Address Pointer -- TRISB7 TRISC7 -- TRISB6 TRISC6 TRISA5 TRISB5 TRISC5 TRISA4 TRISB4 TRISC4 TRISA3 -- TRISC3 TRISA2 -- TRISC2 TRISA1 -- TRISC1 TRISA0 -- TRISC0
--11 1111 1111 ---1111 1111 -- --
Unimplemented Unimplemented -- GIE -- OSFIE -- -- -- Unimplemented Timer2 Period Register Synchronous Serial Port (I2C mode) Address Register MSK7 SMP -- -- -- CSRC BRG7 BRG15 ABDOVF MSK6 CKE -- -- -- TX9 BRG6 BRG14 RCIDL MSK5 D/A WPUA5 IOCA5 -- TXEN BRG5 BRG13 -- MSK4 P WPUA4 IOCA4 WDTPS3 SYNC BRG4 BRG12 SCKP MSK3 S -- IOCA3 WDTPS2 SENDB BRG3 BRG11 BRG16 MSK2 R/W WPUA2 IOCA2 WDTPS1 BRGH BRG2 BRG10 -- MSK1 UA WPUA1 IOCA1 WDTPS0 TRMT BRG1 BRG9 WUE MSK0 BF WPUA0 IOCA0 SWDTEN TX9D BRG0 BRG8 ABDEN -- PEIE ADIE
(4)
-- T0IE RCIE
(2)
Write Buffer for the upper 5 bits of the Program Counter INTE TXIE
(2)
---0 0000 0000 000x -000 0000 0000 -----01 --qq -110 q000 ---0 0000 -- 1111 1111 0000 0000 1111 1111 0000 0000 --11 -111 --00 0000 ---0 1000 0000 0010 0000 0000 0000 0000 01-0 0-00 -- -- xxxx xxxx
RABIE SSPIE -- -- OSTS TUN3
(5)
T0IF CCP1IE -- -- HTS TUN2
(3)
INTF TMR2IE -- POR LTS TUN1
(3)
RABIF(1) TMR1IE -- BOR SCS TUN0
C2IE -- IRCF2 --
C1IE
EEIE
ULPWUE SBOREN IRCF1 -- IRCF0 TUN4
SSPSTAT(5) WPUA(6) IOCA WDTCON TXSTA(2) SPBRG(2) SPBRGH(2) BAUDCTL(2) -- -- ADRESL(4) ADCON1(4)
Unimplemented Unimplemented A/D Result Register Low Byte -- ADCS2 ADCS1 ADCS0 -- -- -- --
-000 ----
Legend: Note 1: 2: 3: 4: 5: 6: 7:
- = Unimplemented locations read as `0', u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented MCLR and WDT Reset do not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the mismatch exists. PIC16F687/PIC16F689/PIC16F690 only. PIC16F685/PIC16F690 only. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only. PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. RA3 pull-up is enabled when pin is configured as MCLR in Configuration Word. Accessible only when SSPCON register bits SSPM<3:0> = 1001.
(c) 2007 Microchip Technology Inc.
DS41262D-page 33
PIC16F631/677/685/687/689/690
TABLE 2-3:
Addr Bank 2 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h INDF TMR0 PCL STATUS FSR PORTA(4) PORTB(4) PORTC(4) -- -- Addressing this location uses contents of FSR to address data memory (not a physical register) Timer0 Module Register Program Counter's (PC) Least Significant Byte IRP RP1 RP0 TO PD Z DC C xxxx xxxx xxxx xxxx 0000 0000 0001 1xxx xxxx xxxx RA4 RB4 RC4 RA3 -- RC3 RA2 -- RC2 RA1 -- RC1 RA0 -- RC0 --xx xxxx xxxx ---xxxx xxxx -- -- -- PEIE EEDAT6 EEADR6 -- -- -- T0IE EEDAT5 EEADR5 Write Buffer for the upper 5 bits of the Program Counter INTE EEDAT4 EEADR4 RABIE EEDAT3 EEADR3 EEDATH3 T0IF EEDAT2 EEADR2 EEDATH2 INTF EEDAT1 EEADR1 EEDATH1 RABIF(1) EEDAT0 EEADR0 ---0 0000 0000 000x 0000 0000 0000 0000 44,201 81,201 44,201 36,201 44,201 59,201 69,201 76,201 -- -- 44,201 38,201 120,202 120,202 120,202 120,202 -- -- -- -- -- 70,202 70,202 -- 106,202 98,202 99,202 101,202 -- -- 61,202 115,202 Name
PIC16F631/677/685/687/689/690 SPECIAL FUNCTION REGISTERS SUMMARY BANK 2
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Page
Indirect Data Memory Address Pointer -- RB7 RC7 Unimplemented Unimplemented -- GIE EEDAT7 EEADR7(3) -- -- Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented WPUB7 IOCB7 -- WPUB6 IOCB6 WPUB5 IOCB5 WPUB4 IOCB4 -- -- -- -- -- -- -- -- -- RB6 RC6 RA5 RB5 RC5
10Ah PCLATH 10Bh INTCON 10Ch EEDAT 10Dh EEADR 10Eh EEDATH(2) 10Fh EEADRH 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh -- -- -- -- -- WPUB IOCB
(2)
EEDATH5 EEDATH4 -- --
EEDATH0 --00 0000
EEADRH3 EEADRH2 EEADRH1 EEADRH0 ---- 0000 -- -- -- -- -- 1111 ---0000 -----
Unimplemented C1VREN C1ON C2ON MC1OUT C2VREN C1OUT C2OUT MC2OUT VRR C1OE C2OE -- VP6EN C1POL C2POL -- VR3 -- -- -- VR2 C1R C2R -- VR1 C1CH1 C2CH1 T1GSS VR0 C1CH0 C2CH0 C2SYNC
VRCON CM1CON0 CM2CON0 CM2CON1 -- -- ANSEL ANSELH(3)
0000 0000 0000 -000 0000 -000 00-- --10 -- --
Unimplemented Unimplemented ANS7 -- ANS6 -- ANS5 -- ANS4 -- ANS3(3) ANS11 ANS2(3) ANS10 ANS1 ANS9 ANS0 ANS8
1111 1111 ---- 1111
Legend: Note 1: 2: 3: 4:
- = Unimplemented locations read as `0', u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented MCLR and WDT Reset does not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the mismatch exists. PIC16F685/PIC16F689/PIC16F690 only. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only. Port pins with analog functions controlled by the ANSEL and ANSELH registers will read `0' immediately after a Reset even though the data latches are either undefined (POR) or unchanged (other Resets).
DS41262D-page 34
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 2-4:
Addr Bank 3 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18Ah 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 19Dh 19Eh 19Fh Legend: Note 1: 2: INDF OPTION_REG PCL STATUS FSR TRISA TRISB TRISC -- -- PCLATH INTCON EECON1 EECON2 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- PSTRCON(2) SRCON -- Addressing this location uses contents of FSR to address data memory (not a physical register) xxxx xxxx RABPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 0000 0000 PD Z DC C 0001 1xxx xxxx xxxx TRISA3 -- TRISC3 TRISA2 -- TRISC2 TRISA1 -- TRISC1 TRISA0 -- TRISC0 --11 1111 1111 ---1111 1111 -- -- -- PEIE -- -- T0IE -- Write Buffer for the upper 5 bits of the Program Counter INTE -- RABIE WRERR T0IF WREN INTF WR RABIF(1) RD ---0 0000 0000 000x x--- x000 ---- ----- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- SR0 -- C1SEN STRSYNC C2REN STRD PULSS STRC PULSR STRB -- STRA -- ---0 0001 0000 00--- 44,201 37,201 44,201 36,201 44,201 59,201 70,202 76,202 -- -- 44,201 38,201 121,202 119,202 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 145,202 103,202 -- Name
PIC16F631/677/685/687/689/690 SPECIAL FUNCTION REGISTERS SUMMARY BANK 3
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Page
Program Counter's (PC) Least Significant Byte IRP RP1 RP0 TO
Indirect Data Memory Address Pointer -- TRISB7 TRISC7 -- TRISB6 TRISC6 TRISA5 TRISB5 TRISC5 TRISA4 TRISB4 TRISC4
Unimplemented Unimplemented -- GIE EEPGD(2)
EEPROM Control Register 2 (not a physical register) Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented Unimplemented -- SR1
Unimplemented
- = Unimplemented locations read as `0', u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented MCLR and WDT Reset does not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the mismatch exists. PIC16F685/PIC16F690 only.
(c) 2007 Microchip Technology Inc.
DS41262D-page 35
PIC16F631/677/685/687/689/690
2.2.2.1 STATUS Register
The STATUS register, shown in Register 2-1, contains: * the arithmetic status of the ALU * the Reset status * the bank select bits for data memory (GPR and SFR) The STATUS register can be the destination for any instruction, like any other register. If the STATUS register is the destination for an instruction that affects the Z, DC or C bits, then the write to these three bits is disabled. These bits are set or cleared according to the device logic. Furthermore, the TO and PD bits are not writable. 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 and MOVWF instructions are used to alter the STATUS register, because these instructions do not affect any Status bits. For other instructions not affecting any Status bits, see Section 15.0 "Instruction Set Summary" Note 1: The C and DC bits operate as a Borrow and Digit Borrow out bit, respectively, in subtraction. See the SUBLW and SUBWF instructions for examples.
REGISTER 2-1:
R/W-0 IRP bit 7 Legend: R = Readable bit -n = Value at POR bit 7
STATUS: STATUS REGISTER
R/W-0 RP1 R/W-0 RP0 R-1 TO R-1 PD R/W-x Z R/W-x DC(1) R/W-x C(1) bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
IRP: Register Bank Select bit (used for indirect addressing) 1 = Bank 2, 3 (100h-1FFh) 0 = Bank 0, 1 (00h-FFh) RP<1:0>: Register Bank Select bits (used for direct addressing) 00 = Bank 0 (00h-7Fh) 01 = Bank 1 (80h-FFh) 10 = Bank 2 (100h-17Fh) 11 = Bank 3 (180h-1FFh) TO: Time-out bit 1 = After power-up, CLRWDT instruction or SLEEP instruction 0 = A WDT time-out occurred PD: Power-down bit 1 = After power-up or by the CLRWDT instruction 0 = By execution of the SLEEP instruction 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 (ADDWF, ADDLW,SUBLW,SUBWF instructions)(1) 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 C: Carry/Borrow bit(1) (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1) 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 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-order or low-order bit of the source register.
bit 6-5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1:
DS41262D-page 36
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
2.2.2.2 OPTION Register
Note: To achieve a 1:1 prescaler assignment for Timer0, assign the prescaler to the WDT by setting PSA bit of the OPTION register to `1'. See Section 6.3 "Timer1 Prescaler". The OPTION register, shown in Register 2-2, is a readable and writable register, which contains various control bits to configure: * * * * Timer0/WDT prescaler External RA2/INT interrupt Timer0 Weak pull-ups on PORTA/PORTB
REGISTER 2-2:
R/W-1 RABPU bit 7 Legend: R = Readable bit -n = Value at POR bit 7
OPTION_REG: OPTION REGISTER
R/W-1 INTEDG R/W-1 T0CS R/W-1 T0SE R/W-1 PSA R/W-1 PS2 R/W-1 PS1 R/W-1 PS0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
RABPU: PORTA/PORTB Pull-up Enable bit 1 = PORTA/PORTB pull-ups are disabled 0 = PORTA/PORTB pull-ups are enabled by individual PORT latch values INTEDG: Interrupt Edge Select bit 1 = Interrupt on rising edge of RA2/INT pin 0 = Interrupt on falling edge of RA2/INT pin T0CS: Timer0 Clock Source Select bit 1 = Transition on RA2/T0CKI pin 0 = Internal instruction cycle clock (FOSC/4) T0SE: Timer0 Source Edge Select bit 1 = Increment on high-to-low transition on RA2/T0CKI pin 0 = Increment on low-to-high transition on RA2/T0CKI pin PSA: Prescaler Assignment bit 1 = Prescaler is assigned to the WDT 0 = Prescaler is assigned to the Timer0 module PS<2:0>: Prescaler Rate Select bits
Bit Value 000 001 010 011 100 101 110 111 Timer0 Rate 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 WDT Rate 1:1 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128
bit 6
bit 5
bit 4
bit 3
bit 2-0
(c) 2007 Microchip Technology Inc.
DS41262D-page 37
PIC16F631/677/685/687/689/690
2.2.2.3 INTCON Register
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, GIE of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. The INTCON register, shown in Register 2-3, is a readable and writable register, which contains the various enable and flag bits for TMR0 register overflow, PORTA change and external RA2/AN2/T0CKI/INT/C1OUT pin interrupts.
REGISTER 2-3:
R/W-0 GIE bit 7 Legend: R = Readable bit -n = Value at POR bit 7
INTCON: INTERRUPT CONTROL REGISTER
R/W-0 PEIE R/W-0 T0IE R/W-0 INTE R/W-0 RABIE(1,3) R/W-0 T0IF(2) R/W-0 INTF R/W-x RABIF bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
GIE: Global Interrupt Enable bit 1 = Enables all unmasked interrupts 0 = Disables all interrupts PEIE: Peripheral Interrupt Enable bit 1 = Enables all unmasked peripheral interrupts 0 = Disables all peripheral interrupts T0IE: Timer0 Overflow Interrupt Enable bit 1 = Enables the Timer0 interrupt 0 = Disables the Timer0 interrupt INTE: RA2/INT External Interrupt Enable bit 1 = Enables the RA2/INT external interrupt 0 = Disables the RA2/INT external interrupt RABIE: PORTA/PORTB Change Interrupt Enable bit(1,3) 1 = Enables the PORTA/PORTB change interrupt 0 = Disables the PORTA/PORTB change interrupt T0IF: Timer0 Overflow Interrupt Flag bit(2) 1 = TMR0 register has overflowed (must be cleared in software) 0 = TMR0 register did not overflow INTF: RA2/INT External Interrupt Flag bit 1 = The RA2/INT external interrupt occurred (must be cleared in software) 0 = The RA2/INT external interrupt did not occur RABIF: PORTA/PORTB Change Interrupt Flag bit 1 = When at least one of the PORTA or PORTB general purpose I/O pins changed state (must be cleared in software) 0 = None of the PORTA or PORTB general purpose I/O pins have changed state IOCA or IOCB register must also be enabled. T0IF bit is set when Timer0 rolls over. Timer0 is unchanged on Reset and should be initialized before clearing T0IF bit. Includes ULPWU interrupt.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1: 2: 3:
DS41262D-page 38
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
2.2.2.4 PIE1 Register
Note: Bit PEIE of the INTCON register must be set to enable any peripheral interrupt. The PIE1 register contains the interrupt enable bits, as shown in Register 2-4.
REGISTER 2-4:
U-0
--
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0 ADIE
(5)
R/W-0 RCIE
(3)
R/W-0 TXIE
(3)
R/W-0 SSPIE
(4)
R/W-0 CCP1IE
(2)
R/W-0 TMR2IE
(1)
R/W-0 TMR1IE bit 0
bit 7 Legend: R = Readable bit -n = Value at POR bit 7 bit 6 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' ADIE: A/D Converter (ADC) Interrupt Enable bit(5) 1 = Enables the ADC interrupt 0 = Disables the ADC interrupt RCIE: EUSART Receive Interrupt Enable bit(3) 1 = Enables the EUSART receive interrupt 0 = Disables the EUSART receive interrupt TXIE: EUSART Transmit Interrupt Enable bit(5) 1 = Enables the EUSART transmit interrupt 0 = Disables the EUSART transmit interrupt SSPIE: Synchronous Serial Port (SSP) Interrupt Enable bit(4) 1 = Enables the SSP interrupt 0 = Disables the SSP interrupt CCP1IE: CCP1 Interrupt Enable bit(2) 1 = Enables the CCP1 interrupt 0 = Disables the CCP1 interrupt TMR2IE: Timer2 to PR2 Match Interrupt Enable bit(1) 1 = Enables the Timer2 to PR2 match interrupt 0 = Disables the Timer2 to PR2 match interrupt TMR1IE: Timer1 Overflow Interrupt Enable bit 1 = Enables the Timer1 overflow interrupt 0 = Disables the Timer1 overflow interrupt PIC16F685/PIC16F690 only. PIC16F685/PIC16F689/PIC16F690 only. PIC16F687/PIC16F689/PIC16F690 only. PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only.
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1: 2: 3: 4: 5:
(c) 2007 Microchip Technology Inc.
DS41262D-page 39
PIC16F631/677/685/687/689/690
2.2.2.5 PIE2 Register
Note: Bit PEIE of the INTCON register must be set to enable any peripheral interrupt. The PIE2 register contains the interrupt enable bits, as shown in Register 2-5.
REGISTER 2-5:
R/W-0 OSFIE bit 7 Legend: R = Readable bit -n = Value at POR bit 7
PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
R/W-0 C2IE R/W-0 C1IE R/W-0 EEIE U-0 -- U-0 -- U-0 -- U-0 -- bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
OSFIE: Oscillator Fail Interrupt Enable bit 1 = Enables oscillator fail interrupt 0 = Disables oscillator fail interrupt C2IE: Comparator C2 Interrupt Enable bit 1 = Enables Comparator C2 interrupt 0 = Disables Comparator C2 interrupt C1IE: Comparator C1 Interrupt Enable bit 1 = Enables Comparator C1 interrupt 0 = Disables Comparator C1 interrupt EEIE: EE Write Operation Interrupt Enable bit 1 = Enables write operation interrupt 0 = Disables write operation interrupt Unimplemented: Read as `0'
bit 6
bit 5
bit 4
bit 3-0
DS41262D-page 40
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
2.2.2.6 PIR1 Register
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, GIE of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. The PIR1 register contains the interrupt flag bits, as shown in Register 2-6.
REGISTER 2-6:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7 bit 6
PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1
R/W-0 ADIF(5) R-0 RCIF(3) R-0 TXIF(3) R/W-0 SSPIF(4) R/W-0 CCP1IF(2) R/W-0 TMR2IF(1) R/W-0 TMR1IF bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' ADIF: A/D Converter Interrupt Flag bit(5) 1 = A/D conversion complete (must be cleared in software) 0 = A/D conversion has not completed or has not been started RCIF: EUSART Receive Interrupt Flag bit(3) 1 = The EUSART receive buffer is full (cleared by reading RCREG) 0 = The EUSART receive buffer is not full TXIF: EUSART Transmit Interrupt Flag bit(3) 1 = The EUSART transmit buffer is empty (cleared by writing to TXREG) 0 = The EUSART transmit buffer is full SSPIF: Synchronous Serial Port (SSP) Interrupt Flag bit(4) 1 = The Transmission/Reception is complete (must be cleared in software) 0 = Waiting to Transmit/Receive CCP1IF: CCP1 Interrupt Flag bit(2) 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: Timer2 to PR2 Interrupt Flag bit(1) 1 = A Timer2 to PR2 match occurred (must be cleared in software) 0 = No Timer2 to PR2 match occurred TMR1IF: Timer1 Overflow Interrupt Flag bit 1 = The TMR1 register overflowed (must be cleared in software) 0 = The TMR1 register did not overflow PIC16F685/PIC16F690 only. PIC16F685/PIC16F689/PIC16F690 only. PIC16F687/PIC16F689/PIC16F690 only. PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only.
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1: 2: 3: 4: 5:
(c) 2007 Microchip Technology Inc.
DS41262D-page 41
PIC16F631/677/685/687/689/690
2.2.2.7 PIR2 Register
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, GIE of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. The PIR2 register contains the interrupt flag bits, as shown in Register 2-7.
REGISTER 2-7:
R/W-0 OSFIF bit 7 Legend: R = Readable bit -n = Value at POR bit 7
PIR2: PERIPHERAL INTERRUPT REQUEST REGISTER 2
R/W-0 C2IF R/W-0 C1IF R/W-0 EEIF U-0 -- U-0 -- U-0 -- U-0 -- bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
OSFIF: Oscillator Fail Interrupt Flag bit 1 = System oscillator failed, clock input has changed to INTOSC (must be cleared in software) 0 = System clock operating C2IF: Comparator C2 Interrupt Flag bit 1 = Comparator output (C2OUT bit) has changed (must be cleared in software) 0 = Comparator output (C2OUT bit) has not changed C1IF: Comparator C1 Interrupt Flag bit 1 = Comparator output (C1OUT bit) has changed (must be cleared in software) 0 = Comparator output (C1OUT bit) has not changed EEIF: EE Write Operation Interrupt Flag bit 1 = Write operation completed (must be cleared in software) 0 = Write operation has not completed or has not started Unimplemented: Read as `0'
bit 6
bit 5
bit 4
bit 3-0
DS41262D-page 42
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
2.2.2.8 PCON Register
The Power Control (PCON) register (see Register 2-8) contains flag bits to differentiate between a: * * * * Power-on Reset (POR) Brown-out Reset (BOR) Watchdog Timer Reset (WDT) External MCLR Reset
The PCON register also controls the Ultra Low-Power Wake-up and software enable of the BOR.
REGISTER 2-8:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5
PCON: POWER CONTROL REGISTER
U-0 -- R/W-0 ULPWUE R/W-1 SBOREN(1) U-0 -- U-0 -- R/W-0 POR R/W-x BOR bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' ULPWUE: Ultra Low-Power Wake-up Enable bit 1 = Ultra Low-Power Wake-up enabled 0 = Ultra Low-Power Wake-up disabled SBOREN: Software BOR Enable bit(1) 1 = BOR enabled 0 = BOR disabled Unimplemented: Read as `0' POR: Power-on Reset Status bit 1 = No Power-on Reset 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 = No Brown-out Reset occurred 0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs) BOREN<1:0> = 01 in the Configuration Word register for this bit to control the BOR.
bit 4
bit 3-2 bit 1
bit 0
Note 1:
(c) 2007 Microchip Technology Inc.
DS41262D-page 43
PIC16F631/677/685/687/689/690
2.3 PCL and PCLATH
2.3.2 STACK
The Program Counter (PC) is 13 bits wide. The low byte comes from the PCL register, which is a readable and writable register. The high byte (PC<12:8>) is not directly readable or writable and comes from PCLATH. On any Reset, the PC is cleared. Figure 2-9 shows the two situations for the loading of the PC. The upper example in Figure 2-9 shows how the PC is loaded on a write to PCL (PCLATH<4:0> PCH). The lower example in Figure 2-9 shows how the PC is loaded during a CALL or GOTO instruction (PCLATH<4:3> PCH). The PIC16F631/677/685/687/689/690 devices have an 8-level x 13-bit wide hardware stack (see Figures 2-2 and 2-3). The stack space is not part of either program or data space and the Stack Pointer is not readable or writable. The PC is PUSHed onto the stack when a CALL instruction is executed or an interrupt causes a branch. The stack is POPed in the event of a RETURN, RETLW or a RETFIE instruction execution. PCLATH is not affected by a PUSH or POP operation. The stack operates as a circular buffer. This means that after the stack has been PUSHed eight times, the ninth push overwrites the value that was stored from the first push. The tenth push overwrites the second push (and so on). Note 1: There are no Status bits to indicate stack overflow or stack underflow conditions. 2: There are no instructions/mnemonics called PUSH or POP. These are actions that occur from the execution of the CALL, RETURN, RETLW and RETFIE instructions or the vectoring to an interrupt address.
FIGURE 2-9:
PCH 12 PC 5 8 7
LOADING OF PC IN DIFFERENT SITUATIONS
PCL 0 Instruction with PCL as Destination ALU Result
PCLATH<4:0>
8
PCLATH PCH 12 PC 2 PCLATH<4:3> 11 OPCODE<10:0> PCLATH 11 10 8 7 PCL 0 GOTO, CALL
2.4
Indirect Addressing, INDF and FSR Registers
The INDF register is not a physical register. Addressing the INDF register will cause indirect addressing. Indirect addressing is possible by using the INDF register. Any instruction using the INDF register actually accesses data pointed to by the File Select Register (FSR). Reading INDF itself indirectly will produce 00h. Writing to the INDF register indirectly results in a no operation (although Status bits may be affected). An effective 9-bit address is obtained by concatenating the 8-bit FSR and the IRP bit of the STATUS register, as shown in Figure 2-10. A simple program to clear RAM location 20h-2Fh using indirect addressing is shown in Example 2-1.
2.3.1
MODIFYING PCL
Executing any instruction with the PCL register as the destination simultaneously causes the Program Counter PC<12:8> bits (PCH) to be replaced by the contents of the PCLATH register. This allows the entire contents of the program counter to be changed by writing the desired upper 5 bits to the PCLATH register. When the lower 8 bits are written to the PCL register, all 13 bits of the program counter will change to the values contained in the PCLATH register and those being written to the PCL register. A computed GOTO is accomplished by adding an offset to the program counter (ADDWF PCL). Care should be exercised when jumping into a look-up table or program branch table (computed GOTO) by modifying the PCL register. Assuming that PCLATH is set to the table start address, if the table length is greater than 255 instructions or if the lower 8 bits of the memory address rolls over from 0xFF to 0x00 in the middle of the table, then PCLATH must be incremented for each address rollover that occurs between the table beginning and the target location within the table. For more information refer to Application Note AN556, "Implementing a Table Read" (DS00556).
EXAMPLE 2-1:
MOVLW MOVWF NEXT CLRF INCF BTFSS GOTO CONTINUE
INDIRECT ADDRESSING
0x20 FSR INDF FSR FSR,4 NEXT ;initialize pointer ;to RAM ;clear INDF register ;inc pointer ;all done? ;no clear next ;yes continue
DS41262D-page 44
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 2-10: DIRECT/INDIRECT ADDRESSING PIC16F631/677/685/687/689/690
Indirect Addressing 0 IRP 7 File Select Register 0 Direct Addressing RP1 RP0 6 From Opcode
Bank Select
Location Select 00 00h 01 10 11
Bank Select 180h
Location Select
Data Memory
7Fh Bank 0 Bank 1 Bank 2 Bank 3
1FFh
For memory map detail, see Figures 2-6, 2-7 and 2-8.
(c) 2007 Microchip Technology Inc.
DS41262D-page 45
PIC16F631/677/685/687/689/690
NOTES:
DS41262D-page 46
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
3.0
3.1
OSCILLATOR MODULE (WITH FAIL-SAFE CLOCK MONITOR)
Overview
The Oscillator module can be configured in one of eight clock modes. 1. 2. 3. 4. 5. 6. 7. 8. EC - External clock with I/O on OSC2/CLKOUT. LP - 32 kHz Low-Power Crystal mode. XT - Medium Gain Crystal or Ceramic Resonator Oscillator mode. HS - High Gain Crystal or Ceramic Resonator mode. RC - External Resistor-Capacitor (RC) with FOSC/4 output on OSC2/CLKOUT. RCIO - External Resistor-Capacitor (RC) with I/O on OSC2/CLKOUT. INTOSC - Internal oscillator with FOSC/4 output on OSC2 and I/O on OSC1/CLKIN. INTOSCIO - Internal oscillator with I/O on OSC1/CLKIN and OSC2/CLKOUT.
The Oscillator module has a wide variety of clock sources and selection features that allow it to be used in a wide range of applications while maximizing performance and minimizing power consumption. Figure 3-1 illustrates a block diagram of the Oscillator module. Clock sources can be configured from external oscillators, quartz crystal resonators, ceramic resonators and Resistor-Capacitor (RC) circuits. In addition, the system clock source can be configured from one of two internal oscillators, with a choice of speeds selectable via software. Additional clock features include: * Selectable system clock source between external or internal via software. * Two-Speed Start-up mode, which minimizes latency between external oscillator start-up and code execution. * Fail-Safe Clock Monitor (FSCM) designed to detect a failure of the external clock source (LP, XT, HS, EC or RC modes) and switch automatically to the internal oscillator.
Clock Source modes are configured by the FOSC<2:0> bits in the Configuration Word register (CONFIG). The internal clock can be generated from two internal oscillators. The HFINTOSC is a calibrated highfrequency oscillator. The LFINTOSC is an uncalibrated low-frequency oscillator.
FIGURE 3-1:
PIC(R) MCU CLOCK SOURCE BLOCK DIAGRAM
FOSC<2:0> (Configuration Word Register) SCS<0> (OSCCON Register)
External Oscillator OSC2 Sleep OSC1
LP, XT, HS, RC, RCIO, EC MUX INTOSC
IRCF<2:0> (OSCCON Register) 8 MHz Internal Oscillator 4 MHz 2 MHz Postscaler 101 100 500 kHz 250 kHz 125 kHz LFINTOSC 31 kHz 31 kHz 011 010 001 000 MUX 1 MHz HFINTOSC 8 MHz 111 110
System Clock (CPU and Peripherals)
Power-up Timer (PWRT) Watchdog Timer (WDT) Fail-Safe Clock Monitor (FSCM)
(c) 2007 Microchip Technology Inc.
DS41262D-page 47
PIC16F631/677/685/687/689/690
3.2 Oscillator Control
The Oscillator Control (OSCCON) register (Figure 3-1) controls the system clock and frequency selection options. The OSCCON register contains the following bits: * Frequency selection bits (IRCF) * Frequency Status bits (HTS, LTS) * System clock control bits (OSTS, SCS)
REGISTER 3-1:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7 bit 6-4
OSCCON: OSCILLATOR CONTROL REGISTER
R/W-1 IRCF2 R/W-1 IRCF1 R/W-0 IRCF0 R-1 OSTS(1) R-0 HTS R-0 LTS R/W-0 SCS bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' IRCF<2:0>: Internal Oscillator Frequency Select bits 111 = 8 MHz 110 = 4 MHz (default) 101 = 2 MHz 100 = 1 MHz 011 = 500 kHz 010 = 250 kHz 001 = 125 kHz 000 = 31 kHz (LFINTOSC) OSTS: Oscillator Start-up Time-out Status bit(1) 1 = Device is running from the external clock defined by FOSC<2:0> of the CONFIG register 0 = Device is running from the internal oscillator (HFINTOSC or LFINTOSC) HTS: HFINTOSC Status bit (High Frequency - 8 MHz to 125 kHz) 1 = HFINTOSC is stable 0 = HFINTOSC is not stable LTS: LFINTOSC Stable bit (Low Frequency - 31 kHz) 1 = LFINTOSC is stable 0 = LFINTOSC is not stable SCS: System Clock Select bit 1 = Internal oscillator is used for system clock 0 = Clock source defined by FOSC<2:0> of the CONFIG register Bit resets to `0' with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe mode is enabled.
bit 3
bit 2
bit 1
bit 0
Note 1:
DS41262D-page 48
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
3.3 Clock Source Modes 3.4
3.4.1
External Clock Modes
OSCILLATOR START-UP TIMER (OST)
Clock Source modes can be classified as external or internal. * External Clock modes rely on external circuitry for the clock source. Examples are: Oscillator modules (EC mode), quartz crystal resonators or ceramic resonators (LP, XT and HS modes) and Resistor-Capacitor (RC) mode circuits. * Internal clock sources are contained internally within the Oscillator module. The Oscillator module has two internal oscillators: the 8 MHz High-Frequency Internal Oscillator (HFINTOSC) and the 31 kHz Low-Frequency Internal Oscillator (LFINTOSC). The system clock can be selected between external or internal clock sources via the System Clock Select (SCS) bit of the OSCCON register. See Section 3.6 "Clock Switching" for additional information.
If the Oscillator module is configured for LP, XT or HS modes, the Oscillator Start-up Timer (OST) counts 1024 oscillations from OSC1. This occurs following a Power-on Reset (POR) and when the Power-up Timer (PWRT) has expired (if configured), or a wake-up from Sleep. During this time, the program counter does not increment and program execution is suspended. The OST ensures that the oscillator circuit, using a quartz crystal resonator or ceramic resonator, has started and is providing a stable system clock to the Oscillator module. When switching between clock sources, a delay is required to allow the new clock to stabilize. These oscillator delays are shown in Table 3-1. In order to minimize latency between external oscillator start-up and code execution, the Two-Speed Clock Start-up mode can be selected (see Section 3.7 "TwoSpeed Clock Start-up Mode").
TABLE 3-1:
Switch From Sleep/POR Sleep/POR
OSCILLATOR DELAY EXAMPLES
Switch To LFINTOSC HFINTOSC EC, RC EC, RC LP, XT, HS HFINTOSC Frequency 31 kHz 125 kHz to 8 MHz DC - 20 MHz DC - 20 MHz 32 kHz to 20 MHz 125 kHz to 8 MHz Oscillator Delay Oscillator Warm-up Delay (TWARM) 2 cycles 1 cycle of each 1024 Clock Cycles (OST) 1 s (approx.)
LFINTOSC (31 kHz) Sleep/POR LFINTOSC (31 kHz)
3.4.2
EC MODE
FIGURE 3-2:
The External Clock (EC) mode allows an externally generated logic level as the system clock source. When operating in this mode, an external clock source is connected to the OSC1 input and the OSC2 is available for general purpose I/O. Figure 3-2 shows the pin connections for EC mode. The Oscillator Start-up Timer (OST) is disabled when EC mode is selected. Therefore, there is no delay in operation after a Power-on Reset (POR) or wake-up from Sleep. Because the PIC(R) MCU design is fully static, stopping the external clock input will have the effect of halting the device while leaving all data intact. Upon restarting the external clock, the device will resume operation as if no time had elapsed.
EXTERNAL CLOCK (EC) MODE OPERATION
OSC1/CLKIN PIC(R) MCU I/O OSC2/CLKOUT(1)
Clock from Ext. System
Note 1:
Alternate pin functions are listed in the Section 1.0 "Device Overview".
(c) 2007 Microchip Technology Inc.
DS41262D-page 49
PIC16F631/677/685/687/689/690
3.4.3 LP, XT, HS MODES
The LP, XT and HS modes support the use of quartz crystal resonators or ceramic resonators connected to OSC1 and OSC2 (Figure 3-3). The mode selects a low, medium or high gain setting of the internal inverteramplifier to support various resonator types and speed. LP Oscillator mode selects the lowest gain setting of the internal inverter-amplifier. LP mode current consumption is the least of the three modes. This mode is designed to drive only 32.768 kHz tuning-fork type crystals (watch crystals). XT Oscillator mode selects the intermediate gain setting of the internal inverter-amplifier. XT mode current consumption is the medium of the three modes. This mode is best suited to drive resonators with a medium drive level specification. HS Oscillator mode selects the highest gain setting of the internal inverter-amplifier. HS mode current consumption is the highest of the three modes. This mode is best suited for resonators that require a high drive setting. Figure 3-3 and Figure 3-4 show typical circuits for quartz crystal and ceramic resonators, respectively. Note 1: Quartz crystal characteristics vary according to type, package and manufacturer. The user should consult the manufacturer data sheets for specifications and recommended application. 2: Always verify oscillator performance over the VDD and temperature range that is expected for the application. 3: For oscillator design assistance, reference the following Microchip Applications Notes: * AN826, "Crystal Oscillator Basics and Crystal Selection for rfPIC(R) and PIC(R) Devices" (DS00826) * AN849, "Basic PIC(R) Oscillator Design" (DS00849) * AN943, "Practical PIC(R) Oscillator Analysis and Design" (DS00943) * AN949, "Making Your Oscillator Work" (DS00949)
FIGURE 3-4:
FIGURE 3-3:
QUARTZ CRYSTAL OPERATION (LP, XT OR HS MODE)
PIC(R) MCU
C1 OSC1/CLKIN
CERAMIC RESONATOR OPERATION (XT OR HS MODE)
PIC(R) MCU
OSC1/CLKIN To Internal Logic RP(3) RF(2) Sleep
C1 Quartz Crystal
To Internal Logic RF(2) Sleep
C2 Ceramic RS(1) Resonator OSC2/CLKOUT
OSC2/CLKOUT
C2
RS(1)
Note 1:
A series resistor (RS) may be required for ceramic resonators with low drive level.
Note 1: 2:
A series resistor (RS) may be required for quartz crystals with low drive level. The value of RF varies with the Oscillator mode selected (typically between 2 M to 10 M).
2: The value of RF varies with the Oscillator mode selected (typically between 2 M to 10 M). 3: An additional parallel feedback resistor (RP) may be required for proper ceramic resonator operation.
DS41262D-page 50
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
3.4.4 EXTERNAL RC MODES
3.5
Internal Clock Modes
The external Resistor-Capacitor (RC) modes support the use of an external RC circuit. This allows the designer maximum flexibility in frequency choice while keeping costs to a minimum when clock accuracy is not required. There are two modes: RC and RCIO. In RC mode, the RC circuit connects to OSC1. OSC2/ CLKOUT outputs the RC oscillator frequency divided by 4. This signal may be used to provide a clock for external circuitry, synchronization, calibration, test or other application requirements. Figure 3-5 shows the external RC mode connections.
The Oscillator module has two independent, internal oscillators that can be configured or selected as the system clock source. 1. The HFINTOSC (High-Frequency Internal Oscillator) is factory calibrated and operates at 8 MHz. The frequency of the HFINTOSC can be user-adjusted via software using the OSCTUNE register (Register 3-2). The LFINTOSC (Low-Frequency Internal Oscillator) is uncalibrated and operates at 31 kHz.
2.
FIGURE 3-5:
VDD REXT
EXTERNAL RC MODES
PIC(R) MCU
The system clock speed can be selected via software using the Internal Oscillator Frequency Select bits IRCF<2:0> of the OSCCON register. The system clock can be selected between external or internal clock sources via the System Clock Selection (SCS) bit of the OSCCON register. See Section 3.6 "Clock Switching" for more information.
OSC1/CLKIN CEXT VSS FOSC/4 or I/O(2) OSC2/CLKOUT(1)
Internal Clock
3.5.1
INTOSC AND INTOSCIO MODES
Recommended values: 10 k REXT 100 k, <3V 3 k REXT 100 k, 3-5V CEXT > 20 pF, 2-5V Note 1: 2: Alternate pin functions are listed in the Section 1.0 "Device Overview". Output depends upon RC or RCIO Clock mode.
The INTOSC and INTOSCIO modes configure the internal oscillators as the system clock source when the device is programmed using the oscillator selection or the FOSC<2:0> bits in the Configuration Word register (CONFIG). In INTOSC mode, OSC1/CLKIN is available for general purpose I/O. OSC2/CLKOUT outputs the selected internal oscillator frequency divided by 4. The CLKOUT signal may be used to provide a clock for external circuitry, synchronization, calibration, test or other application requirements. In INTOSCIO mode, OSC1/CLKIN and OSC2/CLKOUT are available for general purpose I/O.
In RCIO mode, the RC circuit is connected to OSC1. OSC2 becomes an additional general purpose I/O pin. The RC oscillator frequency is a function of the supply voltage, the resistor (REXT) and capacitor (CEXT) values and the operating temperature. Other factors affecting the oscillator frequency are: * threshold voltage variation * component tolerances * packaging variations in capacitance The user also needs to take into account variation due to tolerance of external RC components used.
3.5.2
HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is a factory calibrated 8 MHz internal clock source. The frequency of the HFINTOSC can be altered via software using the OSCTUNE register (Register 3-2). The output of the HFINTOSC connects to a postscaler and multiplexer (see Figure 3-1). One of seven frequencies can be selected via software using the IRCF<2:0> bits of the OSCCON register. See Section 3.5.4 "Frequency Select Bits (IRCF)" for more information. The HFINTOSC is enabled by selecting any frequency between 8 MHz and 125 kHz by setting the IRCF<2:0> bits of the OSCCON register 000. Then, set the System Clock Source (SCS) bit of the OSCCON register to `1' or enable Two-Speed Start-up by setting the IESO bit in the Configuration Word register (CONFIG) to `1'. The HF Internal Oscillator (HTS) bit of the OSCCON register indicates whether the HFINTOSC is stable or not.
(c) 2007 Microchip Technology Inc.
DS41262D-page 51
PIC16F631/677/685/687/689/690
3.5.2.1 OSCTUNE Register
The HFINTOSC is factory calibrated but can be adjusted in software by writing to the OSCTUNE register (Register 3-2). The default value of the OSCTUNE register is `0'. The value is a 5-bit two's complement number. When the OSCTUNE register is modified, the HFINTOSC frequency will begin shifting to the new frequency. Code execution continues during this shift. There is no indication that the shift has occurred. OSCTUNE does not affect the LFINTOSC frequency. Operation of features that depend on the LFINTOSC clock source frequency, such as the Power-up Timer (PWRT), Watchdog Timer (WDT), Fail-Safe Clock Monitor (FSCM) and peripherals, are not affected by the change in frequency.
REGISTER 3-2:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-5 bit 4-0
OSCTUNE: OSCILLATOR TUNING REGISTER
U-0 -- U-0 -- R/W-0 TUN4 R/W-0 TUN3 R/W-0 TUN2 R/W-0 TUN1 R/W-0 TUN0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' TUN<4:0>: Frequency Tuning bits 01111 = Maximum frequency 01110 = * * * 00001 = 00000 = Oscillator module is running at the calibrated frequency. 11111 = * * * 10000 = Minimum frequency
DS41262D-page 52
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
3.5.3 LFINTOSC 3.5.5
The Low-Frequency Internal Oscillator (LFINTOSC) is an uncalibrated 31 kHz internal clock source. The output of the LFINTOSC connects to a postscaler and multiplexer (see Figure 3-1). Select 31 kHz, via software, using the IRCF<2:0> bits of the OSCCON register. See Section 3.5.4 "Frequency Select Bits (IRCF)" for more information. The LFINTOSC is also the frequency for the Power-up Timer (PWRT), Watchdog Timer (WDT) and Fail-Safe Clock Monitor (FSCM). The LFINTOSC is enabled by selecting 31 kHz (IRCF<2:0> bits of the OSCCON register = 000) as the system clock source (SCS bit of the OSCCON register = 1), or when any of the following are enabled: * Two-Speed Start-up IESO bit of the Configuration Word register = 1 and IRCF<2:0> bits of the OSCCON register = 000 * Power-up Timer (PWRT) * Watchdog Timer (WDT) * Fail-Safe Clock Monitor (FSCM) The LF Internal Oscillator (LTS) bit of the OSCCON register indicates whether the LFINTOSC is stable or not.
HFINTOSC AND LFINTOSC CLOCK SWITCH TIMING
When switching between the LFINTOSC and the HFINTOSC, the new oscillator may already be shut down to save power (see Figure 3-6). If this is the case, there is a delay after the IRCF<2:0> bits of the OSCCON register are modified before the frequency selection takes place. The LTS and HTS bits of the OSCCON register will reflect the current active status of the LFINTOSC and HFINTOSC oscillators. The timing of a frequency selection is as follows: 1. 2. 3. 4. 5. IRCF<2:0> bits of the OSCCON register are modified. If the new clock is shut down, a clock start-up delay is started. Clock switch circuitry waits for a falling edge of the current clock. CLKOUT is held low and the clock switch circuitry waits for a rising edge in the new clock. CLKOUT is now connected with the new clock. LTS and HTS bits of the OSCCON register are updated as required. Clock switch is complete.
6.
See Figure 3-1 for more details. If the internal oscillator speed selected is between 8 MHz and 125 kHz, there is no start-up delay before the new frequency is selected. This is because the old and new frequencies are derived from the HFINTOSC via the postscaler and multiplexer. Start-up delay specifications are located in the oscillator tables of Section 17.0 "Electrical Specifications".
3.5.4
FREQUENCY SELECT BITS (IRCF)
The output of the 8 MHz HFINTOSC and 31 kHz LFINTOSC connects to a postscaler and multiplexer (see Figure 3-1). The Internal Oscillator Frequency Select bits IRCF<2:0> of the OSCCON register select the frequency output of the internal oscillators. One of eight frequencies can be selected via software: * * * * * * * * 8 MHz 4 MHz (Default after Reset) 2 MHz 1 MHz 500 kHz 250 kHz 125 kHz 31 kHz (LFINTOSC) Note: Following any Reset, the IRCF<2:0> bits of the OSCCON register are set to `110' and the frequency selection is set to 4 MHz. The user can modify the IRCF bits to select a different frequency.
(c) 2007 Microchip Technology Inc.
DS41262D-page 53
PIC16F631/677/685/687/689/690
FIGURE 3-6: INTERNAL OSCILLATOR SWITCH TIMING
HFINTOSC HFINTOSC
LFINTOSC (FSCM and WDT disabled)
Start-up Time
2-cycle Sync
Running
LFINTOSC IRCF <2:0> System Clock 0 =0
HFINTOSC HFINTOSC
LFINTOSC (Either FSCM or WDT enabled)
2-cycle Sync
Running
LFINTOSC IRCF <2:0> System Clock
0
=0
LFINTOSC LFINTOSC
HFINTOSC
LFINTOSC turns off unless WDT or FSCM is enabled
Start-up Time
2-cycle Sync
Running
HFINTOSC IRCF <2:0> System Clock =0 1/40
DS41262D-page 54
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
3.6 Clock Switching
The system clock source can be switched between external and internal clock sources via software using the System Clock Select (SCS) bit of the OSCCON register. When the Oscillator module is configured for LP, XT or HS modes, the Oscillator Start-up Timer (OST) is enabled (see Section 3.4.1 "Oscillator Start-up Timer (OST)"). The OST will suspend program execution until 1024 oscillations are counted. Two-Speed Start-up mode minimizes the delay in code execution by operating from the internal oscillator as the OST is counting. When the OST count reaches 1024 and the OSTS bit of the OSCCON register is set, program execution switches to the external oscillator.
3.6.1
SYSTEM CLOCK SELECT (SCS) BIT
The System Clock Select (SCS) bit of the OSCCON register selects the system clock source that is used for the CPU and peripherals. * When the SCS bit of the OSCCON register = 0, the system clock source is determined by configuration of the FOSC<2:0> bits in the Configuration Word register (CONFIG). * When the SCS bit of the OSCCON register = 1, the system clock source is chosen by the internal oscillator frequency selected by the IRCF<2:0> bits of the OSCCON register. After a Reset, the SCS bit of the OSCCON register is always cleared. Note: Any automatic clock switch, which may occur from Two-Speed Start-up or Fail-Safe Clock Monitor, does not update the SCS bit of the OSCCON register. The user can monitor the OSTS bit of the OSCCON register to determine the current system clock source.
3.7.1
TWO-SPEED START-UP MODE CONFIGURATION
Two-Speed Start-up mode is configured by the following settings: * IESO (of the Configuration Word register) = 1; Internal/External Switchover bit (Two-Speed Startup mode enabled). * SCS (of the OSCCON register) = 0. * FOSC<2:0> bits in the Configuration Word register (CONFIG) configured for LP, XT or HS mode. Two-Speed Start-up mode is entered after: * Power-on Reset (POR) and, if enabled, after Power-up Timer (PWRT) has expired, or * Wake-up from Sleep. If the external clock oscillator is configured to be anything other than LP, XT or HS mode, then Twospeed Start-up is disabled. This is because the external clock oscillator does not require any stabilization time after POR or an exit from Sleep.
3.6.2
OSCILLATOR START-UP TIME-OUT STATUS (OSTS) BIT
The Oscillator Start-up Time-out Status (OSTS) bit of the OSCCON register indicates whether the system clock is running from the external clock source, as defined by the FOSC<2:0> bits in the Configuration Word register (CONFIG), or from the internal clock source. In particular, OSTS indicates that the Oscillator Start-up Timer (OST) has timed out for LP, XT or HS modes.
3.7.2
1. 2.
TWO-SPEED START-UP SEQUENCE
3.7
Two-Speed Clock Start-up Mode
3. 4. 5. 6. 7.
Two-Speed Start-up mode provides additional power savings by minimizing the latency between external oscillator start-up and code execution. In applications that make heavy use of the Sleep mode, Two-Speed Start-up will remove the external oscillator start-up time from the time spent awake and can reduce the overall power consumption of the device. This mode allows the application to wake-up from Sleep, perform a few instructions using the INTOSC as the clock source and go back to Sleep without waiting for the primary oscillator to become stable. Note: Executing a SLEEP instruction will abort the oscillator start-up time and will cause the OSTS bit of the OSCCON register to remain clear.
Wake-up from Power-on Reset or Sleep. Instructions begin execution by the internal oscillator at the frequency set in the IRCF<2:0> bits of the OSCCON register. OST enabled to count 1024 clock cycles. OST timed out, wait for falling edge of the internal oscillator. OSTS is set. System clock held low until the next falling edge of new clock (LP, XT or HS mode). System clock is switched to external clock source.
(c) 2007 Microchip Technology Inc.
DS41262D-page 55
PIC16F631/677/685/687/689/690
3.7.3 CHECKING TWO-SPEED CLOCK STATUS
Checking the state of the OSTS bit of the OSCCON register will confirm if the microcontroller is running from the external clock source, as defined by the FOSC<2:0> bits in the Configuration Word register (CONFIG), or the internal oscillator.
FIGURE 3-7:
TWO-SPEED START-UP
HFINTOSC T TOST OSC1 0 1 1022 1023
OSC2 Program Counter PC - N PC PC + 1
System Clock
DS41262D-page 56
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
3.8 Fail-Safe Clock Monitor
3.8.3 FAIL-SAFE CONDITION CLEARING
The Fail-Safe Clock Monitor (FSCM) allows the device to continue operating should the external oscillator fail. The FSCM can detect oscillator failure any time after the Oscillator Start-up Timer (OST) has expired. The FSCM is enabled by setting the FCMEN bit in the Configuration Word register (CONFIG). The FSCM is applicable to all external Oscillator modes (LP, XT, HS, EC, RC and RCIO). The Fail-Safe condition is cleared after a Reset, executing a SLEEP instruction or toggling the SCS bit of the OSCCON register. When the SCS bit is toggled, the OST is restarted. While the OST is running, the device continues to operate from the INTOSC selected in OSCCON. When the OST times out, the Fail-Safe condition is cleared and the device will be operating from the external clock source. The Fail-Safe condition must be cleared before the OSFIF flag can be cleared.
FIGURE 3-8:
FSCM BLOCK DIAGRAM
Clock Monitor Latch S Q
3.8.4
RESET OR WAKE-UP FROM SLEEP
External Clock
LFINTOSC Oscillator 31 kHz (~32 s)
/ 64 488 Hz (~2 ms)
R
Q
The FSCM is designed to detect an oscillator failure after the Oscillator Start-up Timer (OST) has expired. The OST is used after waking up from Sleep and after any type of Reset. The OST is not used with the EC or RC Clock modes so that the FSCM will be active as soon as the Reset or wake-up has completed. When the FSCM is enabled, the Two-Speed Start-up is also enabled. Therefore, the device will always be executing code while the OST is operating. Note:
Clock Failure Detected
Sample Clock
3.8.1
FAIL-SAFE DETECTION
The FSCM module detects a failed oscillator by comparing the external oscillator to the FSCM sample clock. The sample clock is generated by dividing the LFINTOSC by 64. See Figure 3-8. Inside the fail detector block is a latch. The external clock sets the latch on each falling edge of the external clock. The sample clock clears the latch on each rising edge of the sample clock. A failure is detected when an entire halfcycle of the sample clock elapses before the primary clock goes low.
Due to the wide range of oscillator start-up times, the Fail-Safe circuit is not active during oscillator start-up (i.e., after exiting Reset or Sleep). After an appropriate amount of time, the user should check the OSTS bit of the OSCCON register to verify the oscillator start-up and that the system clock switchover has successfully completed.
3.8.2
FAIL-SAFE OPERATION
When the external clock fails, the FSCM switches the device clock to an internal clock source and sets the bit flag OSFIF of the PIR2 register. Setting this flag will generate an interrupt if the OSFIE bit of the PIE2 register is also set. The device firmware can then take steps to mitigate the problems that may arise from a failed clock. The system clock will continue to be sourced from the internal clock source until the device firmware successfully restarts the external oscillator and switches back to external operation. The internal clock source chosen by the FSCM is determined by the IRCF<2:0> bits of the OSCCON register. This allows the internal oscillator to be configured before a failure occurs.
(c) 2007 Microchip Technology Inc.
DS41262D-page 57
PIC16F631/677/685/687/689/690
FIGURE 3-9:
Sample Clock System Clock Output Clock Monitor Output (Q) Failure Detected OSCFIF Oscillator Failure
FSCM TIMING DIAGRAM
Test Note:
Test
Test
The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in this example have been chosen for clarity.
TABLE 3-2:
Name CONFIG(2) OSCCON OSCTUNE PIE1 PIR1 Legend: Note 1: 2:
SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES
Bit 7 CPD -- -- -- -- Bit 6 CP IRCF2 -- ADIE ADIF Bit 5 MCLRE IRCF1 -- RCIE RCIF Bit 4 PWRTE IRCF0 TUN4 TXIE TXIF Bit 3 WDTE OSTS TUN3 SSPIE SSPIF Bit 2 FOSC2 HTS TUN2 CCP1IE CCP1IF Bit 1 FOSC1 LTS TUN1 TMR2IE TMR2IF Bit 0 FOSC0 SCS TUN0 TMR1IE TMR1IF Value on POR, BOR -- -110 x000 ---0 0000 -000 0000 -000 0000 Value on all other Resets(1) -- -110 x000 ---u uuuu -000 0000 -000 0000
x = unknown, u = unchanged, - = unimplemented locations read as `0'. Shaded cells are not used by oscillators. Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation. See Configuration Word register (Register 14-1) for operation of all register bits.
DS41262D-page 58
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.0 I/O PORTS
There are as many as eighteen general purpose I/O pins available. Depending on which peripherals are enabled, some or all of the pins may not be available as general purpose I/O. In general, when a peripheral is enabled, the associated pin may not be used as a general purpose I/O pin. port pins are read, this value is modified and then written to the PORT data latch. RA3 reads `0' when MCLRE = 1. The TRISA register controls the PORTA pin output drivers, even when they are being used as analog inputs. The user should ensure the bits in the TRISA register are maintained set when using them as analog inputs. I/O pins configured as analog input always read `0'. Note: The ANSEL register must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read `0'.
4.1
PORTA and the TRISA Registers
PORTA is a 6-bit wide, bidirectional port. The corresponding data direction register is TRISA (Register 4-2). Setting a TRISA bit (= 1) will make the corresponding PORTA pin an input (i.e., disable the output driver). Clearing a TRISA bit (= 0) will make the corresponding PORTA pin an output (i.e., enables output driver and puts the contents of the output latch on the selected pin). The exception is RA3, which is input only and its TRIS bit will always read as `1'. Example 4-1 shows how to initialize PORTA. Reading the PORTA register (Register 4-1) reads the status of the pins, whereas writing to it will write to the PORT latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the
EXAMPLE 4-1:
BCF BCF CLRF BSF CLRF BSF BCF MOVLW MOVWF BCF STATUS,RP0 STATUS,RP1 PORTA STATUS,RP1 ANSEL STATUS,RP0 STATUS,RP1 0Ch TRISA STATUS,RP0
INITIALIZING PORTA
;Bank 0 ; ;Init PORTA ;Bank 2 ;digital I/O ;Bank 1 ; ;Set RA<3:2> as inputs ;and set RA<5:4,1:0> ;as outputs ;Bank 0
REGISTER 4-1:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5-0
PORTA: PORTA REGISTER
U-0 -- R/W-x RA5 R/W-x RA4 R-x RA3 R/W-x RA2 R/W-x RA1 R/W-x RA0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' RA<5:0>: PORTA I/O Pin bit 1 = Port pin is > VIH 0 = Port pin is < VIL
REGISTER 4-2:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5-0
TRISA: PORTA TRI-STATE REGISTER
U-0 -- R/W-1 TRISA5 R/W-1 TRISA4 R-1 TRISA3 R/W-1 TRISA2 R/W-1 TRISA1 R/W-1 TRISA0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' TRISA<5:0>: PORTA Tri-State Control bit 1 = PORTA pin configured as an input (tri-stated) 0 = PORTA pin configured as an output TRISA<3> always reads `1'. TRISA<5:4> always reads `1' in XT, HS and LP Oscillator modes.
Note 1: 2:
(c) 2007 Microchip Technology Inc.
DS41262D-page 59
PIC16F631/677/685/687/689/690
4.2 Additional Pin Functions
4.2.3 INTERRUPT-ON-CHANGE
Every PORTA pin on this device family has an interrupt-on-change option and a weak pull-up option. RA0 also has an Ultra Low-Power Wake-up option. The next three sections describe these functions. Each PORTA pin is individually configurable as an interrupt-on-change pin. Control bits IOCAx enable or disable the interrupt function for each pin. Refer to Register 4-6. The interrupt-on-change is disabled on a Power-on Reset. For enabled interrupt-on-change pins, the values are compared with the old value latched on the last read of PORTA. The `mismatch' outputs of the last read are OR'd together to set the PORTA Change Interrupt Flag bit (RABIF) in the INTCON register (Register 2-6). This interrupt can wake the device from Sleep. The user, in the Interrupt Service Routine, clears the interrupt by: a) b) Any read or write of PORTA. This will end the mismatch condition, then, Clear the flag bit RABIF.
4.2.1
ANSEL AND ANSELH REGISTERS
The ANSEL and ANSELH registers are used to disable the input buffers of I/O pins, which allow analog voltages to be applied to those pins without causing excessive current. Setting the ANSx bit of a corresponding pin will cause all digital reads of that pin to return `0' and also permit analog functions of that pin to operate correctly. The state of the ANSx bit has no effect on the digital output function of its corresponding pin. A pin with the TRISx bit clear and ANSx bit set will operate as a digital output, together with the analog input function of that pin. Pins with the ANSx bit set always read `0', which can cause unexpected behavior when executing read or write operations on the port due to the read-modify-write sequence of all such operations.
4.2.2
WEAK PULL-UPS
Each of the PORTA pins, except RA3, has an individually configurable internal weak pull-up. Control bits WPUAx enable or disable each pull-up. Refer to Register 4-4. Each 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 by the RABPU bit of the OPTION register. A weak pull-up is automatically enabled for RA3 when configured as MCLR and disabled when RA3 is an I/O. There is no software control of the MCLR pull-up.
A mismatch condition will continue to set flag bit RABIF. Reading PORTA will end the mismatch condition and allow flag bit RABIF to be cleared. The latch holding the last read value is not affected by a MCLR nor BOR Reset. After these Resets, the RABIF flag will continue to be set if a mismatch is present. Note: If a change on the I/O pin should occur when the read operation is being executed (start of the Q2 cycle), then the RABIF interrupt flag may not get set.
DS41262D-page 60
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 4-3:
R/W-1 ANS7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ANSEL: ANALOG SELECT REGISTER
R/W-1 ANS6 R/W-1 ANS5 R/W-1 ANS4 R/W-1 ANS3 R/W-1 ANS2 R/W-1 ANS1 R/W-1 ANS0 bit 0
ANS<7:0>: Analog Select bits Analog select between analog or digital function on pins AN<7:0>, respectively. 1 = Analog input. Pin is assigned as analog input(1). 0 = Digital I/O. Pin is assigned to port or special function. Setting a pin to an analog input automatically disables the digital input circuitry, weak pull-ups and interrupt-on-change if available. The corresponding TRIS bit must be set to Input mode in order to allow external control of the voltage on the pin.
Note 1:
REGISTER 4-4:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-4 bit 3-0
ANSELH: ANALOG SELECT HIGH REGISTER(2)
U-0 -- U-0 -- U-0 -- R/W-1 ANS11 R/W-1 ANS10 R/W-1 ANS9 R/W-1 ANS8 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' ANS<11:8>: Analog Select bits Analog select between analog or digital function on pins AN<7:0>, respectively. 1 = Analog input. Pin is assigned as analog input(1). 0 = Digital I/O. Pin is assigned to port or special function. Setting a pin to an analog input automatically disables the digital input circuitry, weak pull-ups and interrupt-on-change if available. The corresponding TRIS bit must be set to Input mode in order to allow external control of the voltage on the pin. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only.
Note 1:
2:
(c) 2007 Microchip Technology Inc.
DS41262D-page 61
PIC16F631/677/685/687/689/690
REGISTER 4-5:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5-4 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
WPUA: PORTA REGISTER
U-0 -- R/W-1 WPUA5 R/W-1 WPUA4 U-0 -- R/W-1 WPUA2 R/W-1 WPUA1 R/W-1 WPUA0 bit 0
Unimplemented: Read as `0' WPUA<5:4>: Weak Pull-up Register bit 1 = Pull-up enabled 0 = Pull-up disabled Unimplemented: Read as `0' WPUA<2:0>: Weak Pull-up Register bit 1 = Pull-up enabled 0 = Pull-up disabled Global RABPU bit of the OPTION register must be enabled for individual pull-ups to be enabled. The weak pull-up device is automatically disabled if the pin is in Output mode (TRISA = 0). The RA3 pull-up is enabled when configured as MCLR and disabled as an I/O in the Configuration Word. WPUA<5:4> always reads `1' in XT, HS and LP Oscillator modes.
bit 3 bit 2-0
Note 1: 2: 3: 4:
REGISTER 4-6:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5-0
IOCA: INTERRUPT-ON-CHANGE PORTA REGISTER
U-0 -- R/W-0 IOCA5 R/W-0 IOCA4 R/W-0 IOCA3 R/W-0 IOCA2 R/W-0 IOCA1 R/W-0 IOCA0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' IOCA<5:0>: Interrupt-on-change PORTA Control bit 1 = Interrupt-on-change enabled 0 = Interrupt-on-change disabled Global Interrupt Enable (GIE) must be enabled for individual interrupts to be recognized. IOCA<5:4> always reads `1' in XT, HS and LP Oscillator modes.
Note 1: 2:
DS41262D-page 62
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.2.4 ULTRA LOW-POWER WAKE-UP
The Ultra Low-Power Wake-up (ULPWU) on RA0 allows a slow falling voltage to generate an interrupt-on-change on RA0 without excess current consumption. The mode is selected by setting the ULPWUE bit of the PCON register. This enables a small current sink, which can be used to discharge a capacitor on RA0. Follow these steps to use this feature: a) b) c) d) e) Charge the capacitor on RA0 by configuring the RA0 pin to output (= 1). Configure RA0 as an input. Enable interrupt-on-change for RA0. Set the ULPWUE bit of the PCON register to begin the capacitor discharge. Execute a SLEEP instruction. A series resistor between RA0 and the external capacitor provides overcurrent protection for the RA0/AN0/C1IN+/ICSPDAT/ULPWU pin and can allow for software calibration of the time-out (see Figure 4-1). A timer can be used to measure the charge time and discharge time of the capacitor. The charge time can then be adjusted to provide the desired interrupt delay. This technique will compensate for the affects of temperature, voltage and component accuracy. The Ultra Low-Power Wake-up peripheral can also be configured as a simple Programmable Low-Voltage Detect or temperature sensor. Note: For more information, refer to Application Note AN879, "Using the Microchip Ultra Low-Power Wake-up Module" (DS00879).
When the voltage on RA0 drops below VIL, an interrupt will be generated which will cause the device to wake-up and execute the next instruction. If the GIE bit of the INTCON register is set, the device will then call the interrupt vector (0004h). See Section 4.4.2 "Interrupt-on-change" and Section 14.3.3 "PORTA/PORTB Interrupt" for more information. This feature provides a low-power technique for periodically waking up the device from Sleep. The time-out is dependent on the discharge time of the RC circuit on RA0. See Example 4-2 for initializing the Ultra Low-Power Wake-up module.
EXAMPLE 4-2:
BCF BCF BSF BSF BCF BSF BCF BCF CALL BSF BSF BSF MOVLW MOVWF BCF SLEEP
ULTRA LOW-POWER WAKE-UP INITIALIZATION
;Bank 0 ; ;Set RA0 data latch ;Bank 2 ;RA0 to digital I/O ;Bank 1 ; ;Output high to ;charge capacitor ;Enable ULP Wake-up ;Select RA0 IOC ;RA0 to input ;Enable interrupt ;and clear flag ;Bank 0 ;Wait for IOC
STATUS,RP0 STATUS,RP1 PORTA,0 STATUS,RP1 ANSEL,0 STATUS,RP0 STATUS,RP1 TRISA,0 CapDelay PCON,ULPWUE IOCA,0 TRISA,0 B'10001000' INTCON STATUS,RP0
(c) 2007 Microchip Technology Inc.
DS41262D-page 63
PIC16F631/677/685/687/689/690
4.2.5 PIN DESCRIPTIONS AND DIAGRAMS 4.2.5.1 RA0/AN0/C1IN+/ICSPDAT/ULPWU
Each PORTA pin is multiplexed with other functions. The pins and their combined functions are briefly described here. For specific information about individual functions such as the comparator or the A/D Converter (ADC), refer to the appropriate section in this data sheet. Figure 4-2 shows the diagram for this pin. The RA0/AN0/C1IN+/ICSPDAT/ULPWU pin is configurable to function as one of the following: * * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) an analog input to Comparator C1 In-Circuit Serial ProgrammingTM data an analog input for the Ultra Low-Power Wake-up
FIGURE 4-1:
BLOCK DIAGRAM OF RA0
Analog(1) Input Mode VDD Data Bus D WR WPUDA RD WPUDA Q Weak RABPU CK Q
VDD
D WR PORTA
Q I/O Pin
CK Q
VSS
+ D WR TRISA RD TRISA RD PORTA D WR IOCA RD IOCA Q Q D EN Q D EN Interrupt-on-Change Q3 Q IULP 0 Analog(1) Input Mode 1 VSS ULPWUE
VT
CK Q
CK Q
RD PORTA To Comparator To A/D Converter(2)
Note
1: 2:
ANSEL determines Analog Input mode. Not implemented on PIC16F631.
DS41262D-page 64
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.2.5.2 RA1/AN1/C12IN0-/VREF/ICSPCLK 4.2.5.3 RA2/AN2/T0CKI/INT/C1OUT
Figure 4-2 shows the diagram for this pin. The RA1/AN1/C12IN0-/VREF/ICSPCLK pin is configurable to function as one of the following: * * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) an analog input to Comparator C1 or C2 a voltage reference input for the ADC In-Circuit Serial Programming clock Figure 4-3 shows the diagram for this pin. The RA2/AN2/T0CKI/INT/C1OUT pin is configurable to function as one of the following: * * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) the clock input for TMR0 an external edge triggered interrupt a digital output from Comparator C1
FIGURE 4-2:
Data Bus WR WPUA RD WPUA
BLOCK DIAGRAM OF RA1
Analog(1) Input Mode VDD Weak RABPU
FIGURE 4-3:
Data Bus WR WPUA RD WPUA
BLOCK DIAGRAM OF RA2
Analog(1) Input Mode VDD Weak RABPU C1OUT Enable
D
Q
D CK
Q Q
CK Q
D WR PORTA
Q
VDD WR PORTA I/O Pin
D CK
Q Q C1OUT 1 0
VDD
CK Q
I/O Pin
D WR TRISA RD TRISA RD PORTA D WR IOCA RD IOCA
Q VSS Analog(1) Input Mode RD TRISA RD PORTA Q Q D EN Q D EN Q3 WR IOCA RD IOCA WR TRISA
D CK
Q Q Analog(1) Input Mode VSS
CK Q
D CK
Q Q Q EN Q D EN Q3 D
CK Q
Interrupt-onChange RD PORTA To Comparator To A/D Converter(2) Note 1: 2: ANSEL determines Analog Input mode. Not implemented on PIC16F631.
Interrupt-onChange
RD PORTA
To TMR0 To INT To A/D Converter(2)
Note
1: 2:
ANSEL determines Analog Input mode. Not implemented on PIC16F631.
(c) 2007 Microchip Technology Inc.
DS41262D-page 65
PIC16F631/677/685/687/689/690
4.2.5.4 RA3/MCLR/VPP 4.2.5.5 RA4/AN3/T1G/OSC2/CLKOUT
Figure 4-4 shows the diagram for this pin. The RA3/MCLR/VPP pin is configurable to function as one of the following: * a general purpose input * as Master Clear Reset with weak pull-up Figure 4-5 shows the diagram for this pin. The RA4/AN3/T1G/OSC2/CLKOUT pin is configurable to function as one of the following: * * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) a TMR1 gate input a crystal/resonator connection a clock output
FIGURE 4-4:
BLOCK DIAGRAM OF RA3
VDD MCLRE Weak
FIGURE 4-5:
Input Pin Data Bus D CK Q Q
BLOCK DIAGRAM OF RA4
Analog(3) Input Mode
Data Bus
Reset VSS
MCLRE
RD TRISA RD PORTA D WR IOCA RD IOCA CK Q
CLK(1) Modes VDD Weak
MCLRE
VSS
WR WPUA RD WPUA
RABPU Oscillator Circuit OSC1 CLKOUT Enable D Q Q CLKOUT Enable VSS D Q Q INTOSC/ RC/EC(2) CLKOUT Enable Analog Input Mode FOSC/4 1 0 I/O Pin VDD
Q Q
D EN Q3
Q
D EN WR PORTA
Interrupt-onChange
CK
RD PORTA
WR TRISA RD TRISA RD PORTA
CK
D WR IOCA RD IOCA CK
Q Q Q EN Q D EN Q3 D
Interrupt-onChange
RD PORTA To T1G To A/D Converter(4) Note 1: CLK modes are XT, HS, LP, LPTMR1 and CLKOUT Enable. 2: With CLKOUT option. 3: ANSEL determines Analog Input mode. 4: Not implemented on PIC16F631.
DS41262D-page 66
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.2.5.6 RA5/T1CKI/OSC1/CLKIN
Figure 4-6 shows the diagram for this pin. The RA5/T1CKI/OSC1/CLKIN pin is configurable to function as one of the following: * * * * a general purpose I/O a TMR1 clock input a crystal/resonator connection a clock input
FIGURE 4-6:
BLOCK DIAGRAM OF RA5
INTOSC Mode
TMR1LPEN(1) VDD Weak
Data Bus WR WPUA RD WPUA
D CK
Q Q RABPU Oscillator Circuit OSC2
D WR PORTA CK
Q Q
VDD
I/O Pin D WR TRISA RD TRISA RD PORTA D WR IOCA RD IOCA Q D EN Interrupt-onChange RD PORTA To TMR1 or CLKGEN CK Q Q Q EN Q3 D CK Q Q INTOSC Mode (2) VSS
Note
1: Timer1 LP Oscillator enabled. 2: When using Timer1 with LP oscillator, the Schmitt Trigger is bypassed.
(c) 2007 Microchip Technology Inc.
DS41262D-page 67
PIC16F631/677/685/687/689/690
TABLE 4-1:
Name ADCON0 ANSEL CM1CON0 INTCON IOCA OPTION_REG PORTA SSPCON T1CON TRISA WPUA Legend:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Bit 7 ADFM ANS7 C1ON GIE -- RABPU -- WCOL T1GINV -- -- Bit 6 VCFG ANS6 C1OUT PEIE -- INTEDG -- SSPOV TMR1GE -- -- Bit 5 CHS3 ANS5 C1OE T0IE IOCA5 T0CS RA5 SSPEN Bit 4 CHS2 ANS4 C1POL INTE IOCA4 T0SE RA4 CKP Bit 3 CHS1 ANS3 -- RABIE IOCA3 PSA RA3 SSPM3 Bit 2 CHS0 ANS2 C1R T0IF IOCA2 PS2 RA2 SSPM2 T1SYNC TRISA2 WPUA2 Bit 1 GO/DONE ANS1 C1CH1 INTF IOCA1 PS1 RA1 SSPM1 TMR1CS TRISA1 WPUA1 Bit 0 ADON ANS0 C1CH0 RABIF IOCA0 PS0 RA0 SSPM0 TMR1ON TRISA0 WPUA0 Value on POR, BOR 0000 0000 1111 1111 0000 -000 0000 000x --00 0000 1111 1111 --xx xxxx 0000 0000 0000 0000 --11 1111 --11 -111 Value on all other Resets 0000 0000 1111 1111 0000 -000 0000 000x --00 0000 1111 1111 --uu uuuu 0000 0000 uuuu uuuu --11 1111 --11 -111
T1CKPS1 T1CKPS0 T1OSCEN TRISA5 WPUA5 TRISA4 WPUA4 TRISA3 --
x = unknown, u = unchanged, - = unimplemented locations read as `0'. Shaded cells are not used by PORTA.
DS41262D-page 68
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.3 PORTB and TRISB Registers
4.4.1 WEAK PULL-UPS
PORTB is a 4-bit wide, bidirectional port. The corresponding data direction register is TRISB (Register 4-6). 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., enable the output driver and put the contents of the output latch on the selected pin). Example 4-3 shows how to initialize PORTB. Reading the PORTB register (Register 4-5) reads the status of the pins, whereas writing to it will write to the PORT latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the port pins are read, this value is modified and then written to the PORT data latch. The TRISB register controls the PORTB pin output drivers, even when they are being used as analog inputs. The user should ensure the bits in the TRISB register are maintained set when using them as analog inputs. I/O pins configured as analog input always read `0'. Each of the PORTB pins has an individually configurable internal weak pull-up. Control bits WPUB<7:4> enable or disable each pull-up (see Register 4-9). Each weak pull up is automatically turned off when the port pin is configured as an output. All pull-ups are disabled on a Power-on Reset by the RABPU bit of the OPTION register.
4.4.2
INTERRUPT-ON-CHANGE
Four of the PORTB pins are individually configurable as an interrupt-on-change pin. Control bits IOCB<7:4> enable or disable the interrupt function for each pin. Refer to Register 4-10. The interrupt-on-change feature is disabled on a Power-on Reset. For enabled interrupt-on-change pins, the present value is compared with the old value latched on the last read of PORTB to determine which bits have changed or mismatch the old value. The `mismatch' outputs are OR'd together to set the PORTB Change Interrupt flag bit (RABIF) in the INTCON register (Register 2-3). This interrupt can wake the device from Sleep. The user, in the Interrupt Service Routine, clears the interrupt by: a) b) Any read or write of PORTB. This will end the mismatch condition. Clear the flag bit RABIF.
EXAMPLE 4-3:
BCF BCF CLRF BSF MOVLW MOVWF BCF STATUS,RP0 STATUS,RP1 PORTB STATUS,RP0 FFh TRISB STATUS,RP0
INITIALIZING PORTB
;Bank 0 ; ;Init PORTB ;Bank 1 ;Set RB<7:4> as inputs ; ;Bank 0
Note:
The ANSELH register must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read `0'.
A mismatch condition will continue to set flag bit RABIF. Reading or writing PORTB will end the mismatch condition and allow flag bit RABIF to be cleared. The latch holding the last read value is not affected by a MCLR nor Brown-out Reset. After these Resets, the RABIF flag will continue to be set if a mismatch is present. Note: If a change on the I/O pin should occur when the read operation is being executed (start of the Q2 cycle), then the RABIF interrupt flag may not get set. Furthermore, since a read or write on a port affects all bits of that port, care must be taken when using multiple pins in Interrupt-on-Change mode. Changes on one pin may not be seen while servicing changes on another pin.
4.4
Additional PORTB Pin Functions
PORTB pins RB<7:4> on the device family device have an interrupt-on-change option and a weak pull-up option. The following three sections describe these PORTB pin functions.
REGISTER 4-7:
R/W-x RB7 bit 7
PORTB: PORTB REGISTER
R/W-x RB6 R/W-x RB5 R/W-x RB4 U-0 -- U-0 -- U-0 -- U-0 -- 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
bit 7-4
RB<7:4>: PORTB I/O Pin bit 1 = Port pin is > VIH 0 = Port pin is < VIL Unimplemented: Read as `0'
bit 3-0
(c) 2007 Microchip Technology Inc.
DS41262D-page 69
PIC16F631/677/685/687/689/690
REGISTER 4-8:
R/W-1 TRISB7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-4 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
TRISB: PORTB TRI-STATE REGISTER
R/W-1 TRISB6 R/W-1 TRISB5 R/W-1 TRISB4 U-0 -- U-0 -- U-0 -- U-0 -- bit 0
TRISB<7:4>: PORTB Tri-State Control bit 1 = PORTB pin configured as an input (tri-stated) 0 = PORTB pin configured as an output Unimplemented: Read as `0'
bit 3-0
REGISTER 4-9:
R/W-1 WPUB7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-4
WPUB: WEAK PULL-UP PORTB REGISTER
R/W-1 WPUB6 R/W-1 WPUB5 R/W-1 WPUB4 U-0 -- U-0 -- U-0 -- U-0 -- bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
WPUB<7:4>: Weak Pull-up Register bit 1 = Pull-up enabled 0 = Pull-up disabled Unimplemented: Read as `0' Global RABPU bit of the OPTION register must be enabled for individual pull-ups to be enabled. The weak pull-up device is automatically disabled if the pin is in Output mode (TRISB<7:4> = 0). 2:
bit 3-0 Note 1:
REGISTER 4-10:
R/W-0 IOCB7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-4
IOCB: INTERRUPT-ON-CHANGE PORTB REGISTER
R/W-0 IOCB6 R/W-0 IOCB5 R/W-0 IOCB4 U-0 -- U-0 -- U-0 -- U-0 -- bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
IOCB<7:4>: Interrupt-on-Change PORTB Control bit 1 = Interrupt-on-change enabled 0 = Interrupt-on-change disabled Unimplemented: Read as `0'
bit 3-0
DS41262D-page 70
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.4.3 PIN DESCRIPTIONS AND DIAGRAMS 4.4.3.1 RB4/AN10/SDI/SDA
Each PORTB pin is multiplexed with other functions. The pins and their combined functions are briefly described here. For specific information about individual functions such as the SSP, I2CTM or interrupts, refer to the appropriate section in this data sheet. Figure 4-7 shows the diagram for this pin. The RB4/AN10/SDI/SDA(1) pin is configurable to function as one of the following: * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) a SPI data I/O an I2C data I/O Note 1: SDI and SDA are available on PIC16F687/PIC16F689/PIC16F690 only.
FIGURE 4-7:
Data Bus WR WPUB RD WPUB D Q
BLOCK DIAGRAM OF RB4
Analog(1) Input Mode VDD Weak RABPU
CK Q
D WR PORTB
Q
CK Q
SSPEN SSPSR 1 0
1 0
VDD
I/O Pin
D WR TRISB RD TRISB RD PORTB D WR IOCB RD IOCB CK
Q Q
From 0 1 SSP VSS
1 0
Analog(1) Input Mode
Q Q D EN Q D ST EN Q3
CK Q
Interrupt-onChange RD PORTB To SSPSR To A/D Converter(2)
Available on PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. Note 1: 2: ANSEL determines Analog Input mode. Not implemented on PIC16F631.
(c) 2007 Microchip Technology Inc.
DS41262D-page 71
PIC16F631/677/685/687/689/690
4.4.3.2 RB5/AN11/RX/DT FIGURE 4-8:
Data Bus WR WPUB RD WPUB
BLOCK DIAGRAM OF RB5
Analog(1) Input Mode VDD Weak RABPU SYNC SPEN
Figure 4-8 shows the diagram for this pin. The RB5/AN11/RX/DT(1,2) pin is configurable to function as one of the following: * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) an asynchronous serial input a synchronous serial data I/O Note 1: RX and DT are available on PIC16F687/PIC16F689/PIC16F690 only. 2: AN11 is not implemented on PIC16F631.
D
Q
CK Q
D WR PORTB
Q
CK Q
EUSART DT 0 1
1 0
VDD
D WR TRISB RD TRISB RD PORTB D WR IOCB RD IOCB
Q
From EUSART 0 1 0 1 Analog(1) Input Mode VSS
I/O Pin
CK Q
Q Q D EN Q D ST EN Q3
CK Q
Interrupt-onChange RD PORTB To EUSART RX/DT To A/D Converter(2)
Available on PIC16F687/PIC16F689/PIC16F690 only. Note 1: 2: ANSEL determines Analog Input mode. Not implemented on PIC16F631.
DS41262D-page 72
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.4.3.3 RB6/SCK/SCL FIGURE 4-9:
Data Bus WR WPUB RD WPUB D Q
BLOCK DIAGRAM OF RB6
VDD Weak RABPU
Figure 4-9 shows the diagram for this pin. The RB6/SCK/SCL(1) pin is configurable to function as one of the following: * a general purpose I/O * a SPI clock * an I2CTM clock Note 1: SCK and SCL are available PIC16F677/PIC16F687/PIC16F689/ PIC16F690 only. on
CK Q
D WR PORTB
Q
SSPEN SSP Clock 0 1 0 1 From SSP 0 1
1 0
VDD
CK Q
I/O Pin
D WR TRISB RD TRISB RD PORTB D WR IOCB RD IOCB CK
Q Q
VSS
Q Q D EN Q D ST EN Q3
CK Q
Interrupt-onChange RD PORTB To SSPSR Available on PIC16F677/PIC16F687/PIC16F689/PIC16F690 only.
(c) 2007 Microchip Technology Inc.
DS41262D-page 73
PIC16F631/677/685/687/689/690
4.4.3.4 RB7/TX/CK FIGURE 4-10:
Data Bus WR WPUB RD WPUB D Q
BLOCK DIAGRAM OF RB7
VDD Weak RABPU SPEN
Figure 4-10 shows the diagram for this pin. The RB7/TX/CK(1) pin is configurable to function as one of the following: * a general purpose I/O * an asynchronous serial output * a synchronous clock I/O Note 1: TX and CK are available on PIC16F687/PIC16F689/PIC16F690 only.
CK Q
TXEN SYNC EUSART CK 0 1 EUSART TX 1 0 1 0 0 1 D WR TRISB RD TRISB RD PORTB D WR IOCB RD IOCB Q Q D EN Q D EN Interrupt-onChange RD PORTB Available on PIC16F687/PIC16F689/PIC16F690 only. Q3 Q `1' 1 0
1 0
D WR PORTB
Q
VDD
CK Q
I/O Pin
CK Q
VSS
CK Q
DS41262D-page 74
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 4-2:
Name IOCB INTCON PORTB TRISB WPUB Bit 7 IOCB7 GIE RB7
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Bit 6 IOCB6 PEIE RB6 Bit 5 IOCB5 T0IE RB5 Bit 4 IOCB4 INTE RB4 Bit 3 -- RABIE -- -- -- Bit 2 -- T0IF -- -- -- Bit 1 -- INTF -- -- -- Bit 0 -- RABIF -- -- -- Value on POR, BOR Value on all other Resets
0000 ---- 0000 ---0000 000x 0000 000x xxxx ---- uuuu ---1111 ---- 1111 ---1111 ---- 1111 ----
TRISB7 TRISB6 TRISB5 TRISB4 WPUB7 WPUB6 WPUB5 WPUB4
Legend: x = unknown, u = unchanged, -- = unimplemented read as `0'. Shaded cells are not used by PORTB.
(c) 2007 Microchip Technology Inc.
DS41262D-page 75
PIC16F631/677/685/687/689/690
4.5 PORTC and TRISC Registers
PORTC is a 8-bit wide, bidirectional port. The corresponding data direction register is TRISC (Register 4-10). 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., enable the output driver and put the contents of the output latch on the selected pin). Example 4-4 shows how to initialize PORTC. Reading the PORTC register (Register 4-9) reads the status of the pins, whereas writing to it will write to the PORT latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the port pins are read, this value is modified and then written to the PORT data latch. The TRISC register controls the PORTC pin output drivers, even when they are being used as analog inputs. The user should ensure the bits in the TRISC register are maintained set when using them as analog inputs. I/O pins configured as analog input always read `0'. Note: The ANSEL and ANSELH registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read `0'.
EXAMPLE 4-4:
BCF BCF CLRF BSF CLRF BSF BCF MOVLW MOVWF BCF STATUS,RP0 STATUS,RP1 PORTC STATUS,RP1 ANSEL STATUS,RP0 STATUS,RP1 0Ch TRISC STATUS,RP0
INITIALIZING PORTC
;Bank 0 ; ;Init PORTC ;Bank 2 ;digital I/O ;Bank 1 ; ;Set RC<3:2> as inputs ;and set RC<5:4,1:0> ;as outputs ;Bank 0
REGISTER 4-11:
R/W-0 RC7
PORTC: PORTC REGISTER
R/W-x RC6 R/W-x RC5 R/W-x RC4 R/W-x RC3 R/W-x RC2 R/W-x RC1 R/W-x RC0
bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 0
RC<7:0>: PORTC General Purpose I/O Pin bit 1 = Port pin is > VIH 0 = Port pin is < VIL
REGISTER 4-12:
R/W-1
TRISC7
TRISC: PORTC TRI-STATE REGISTER
R/W-1
TRISC6
R/W-1
TRISC5
R/W-1
TRISC4
R-1
TRISC3
R/W-1
TRISC2
R/W-1
TRISC1
R/W-1
TRISC0
bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
bit 0
TRISC<7:0>: PORTC Tri-State Control bit 1 = PORTC pin configured as an input (tri-stated) 0 = PORTC pin configured as an output
DS41262D-page 76
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.5.1 RC0/AN4/C2IN+ 4.5.3 RC2/AN6/C12IN2-/P1D
The RC0 is configurable to function as one of the following: * a general purpose I/O * an analog input for the ADC (except PIC16F631) * an analog input to Comparator C2 The RC2/AN6/P1D(1) is configurable to function as one of the following: * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) a PWM output an analog input to Comparator C1 or C2 Note 1: P1D is available on PIC16F685/PIC16F690 only.
4.5.2
RC1/AN5/C12IN1-
The RC1 is configurable to function as one of the following: * a general purpose I/O * an analog input for the ADC * an analog input to Comparator C1 or C2
4.5.4
RC3/AN7/C12IN3-/P1C
The RC3/AN7/P1C(1) is configurable to function as one of the following: * * * * * a general purpose I/O an analog input for the ADC (except PIC16F631) a PWM output a PWM output an analog input to Comparator C1 or C2 Note 1: P1C is available on PIC16F685/PIC16F690 only.
I/O Pin
FIGURE 4-11:
Data Bus
BLOCK DIAGRAM OF RC0 AND RC1
D WR PORTC CK
Q Q
VDD
D WR TRISC RD TRISC RD PORTC CK
Q Q Analog Input Mode(1) VSS
FIGURE 4-12:
Data Bus
BLOCK DIAGRAM OF RC2 AND RC3
CCP1OUT Enable
D WR PORTC To Comparators To A/D Converter(2) WR TRISC RD TRISC RD PORTC D CK CK
Q Q CCP1OUT 1 0
1 0
VDD
I/O Pin
Q Q Analog Input Mode(1) VSS
Note
1: 2:
ANSEL determines Analog Input mode. Not implemented on PIC16F631.
To Comparators To A/D Converter(2) Available on PIC16F685/PIC16F690 only. Note 1: 2: ANSEL determines Analog Input mode. Not implemented on PIC16F631.
(c) 2007 Microchip Technology Inc.
DS41262D-page 77
PIC16F631/677/685/687/689/690
4.5.5 RC4/C2OUT/P1B 4.5.6 RC5/CCP1/P1A
The RC4/C2OUT/P1B(1, 2) is configurable to function as one of the following: * a general purpose I/O * a digital output from Comparator C2 * a PWM output Note 1: Enabling both C2OUT and P1B will cause a conflict on RC4 and create unpredictable results. Therefore, if C2OUT is enabled, the ECCP+ can not be used in Half-Bridge or Full-Bridge mode and vise-versa. 2: P1B is available on PIC16F685/PIC16F690 only. The RC5/CCP1/P1A(1) is configurable to function as one of the following: * a general purpose I/O * a digital input/output for the Enhanced CCP * a PWM output Note 1: CCP1 and P1A are available PIC16F685/PIC16F690 only. on
FIGURE 4-14:
Data bus
BLOCK DIAGRAM OF RC5
CCP1OUT Enable
D
Q Q CCP1OUT 1 0 0 1
VDD
FIGURE 4-13:
C2OUT EN CCP1OUT EN C2OUT EN C2OUT CCP1OUT EN CCP1OUT Data Bus D WR PORTC Q
BLOCK DIAGRAM OF RC4
WR PORTC
CK
I/O Pin
D VDD WR TRISC RD TRISC I/O Pin RD PORTC CK
Q Q VSS
1 0
1 0
CK Q
VSS
To Enhanced CCP
D WR TRISC RD TRISC RD PORTC
Q
Available on PIC16F685/PIC16F690 only.
CK Q
Available on PIC16F685/PIC16F690 only.
DS41262D-page 78
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
4.5.7 RC6/AN8/SS 4.5.8 RC7/AN9/SDO
The RC6/AN8/SS(1,2) is configurable to function as one of the following: * a general purpose I/O * an analog input for the ADC (except PIC16F631) * a slave select input Note 1: SS is available on PIC16F687/PIC16F689/PIC16F690 only. 2: AN8 is not implemented on PIC16F631. The RC7/AN9/SDO(1,2) is configurable to function as one of the following: * a general purpose I/O * an analog input for the ADC (except PIC16F631) * a serial data output Note 1: SDO is available on PIC16F687/ PIC16F689/PIC16F690 only. 2: AN9 is not implemented on PIC16F631.
FIGURE 4-15:
Data Bus
BLOCK DIAGRAM OF RC6
FIGURE 4-16:
BLOCK DIAGRAM OF RC7
PORT/SDO Select
D WR PORTC CK
Q Q
VDD
Data Bus SDO D I/O Pin WR PORTC CK Q Q I/O Pin D WR TRISC RD TRISC CK Q Q Analog Input Mode(1) VSS 1 0
1 0
VDD
D WR TRISC RD TRISC RD PORTC CK
Q Q Analog Input Mode(1) VSS
To SS Input To A/D Converter(2) Available on PIC16F685/PIC16F690 only. Note 1: 2: ANSEL determines Analog Input mode. Not implemented on PIC16F631.
RD PORTC To A/D Converter(2)
Available on PIC16F685/PIC16F690 only. Note 1: 2: ANSEL determines Analog Input mode. Not implemented on PIC16F631.
(c) 2007 Microchip Technology Inc.
DS41262D-page 79
PIC16F631/677/685/687/689/690
TABLE 4-3:
Name ANSEL ANSELH CCP1CON(2) CM2CON0 CM2CON1 PORTC PSTRCON SRCON SSPCON(1) TRISC VRCON Legend: Note 1: 2:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Bit 7 ANS7 -- P1M1 C2ON Bit 6 ANS6 -- P1M0 C2OUT MC2OUT RC6 -- SR0 SSPOV TRISC6 C2VREN Bit 5 ANS5 -- DC1B1 C2OE -- RC5 -- C1SEN SSPEN TRISC5 VRR Bit 4 ANS4 -- DC1B0 C2POL -- RC4 STRSYNC C2REN CKP TRISC4 VP6EN Bit 3 ANS3 ANS11 CCP1M3 -- -- RC3 STRD PULSS SSPM3 TRISC3 VR3 Bit 2 ANS2 ANS10 CCP1M2 C2R -- RC2 STRC PULSR SSPM2 TRISC2 VR2 Bit 1 ANS1 ANS9 CCP1M1 C2CH1 T1GSS RC1 STRB -- SSPM1 TRISC1 VR1 Bit 0 ANS0 ANS8 CCP1M0 C2CH0 C2SYNC RC0 STRA -- SSPM0 TRISC0 VR0 Value on POR, BOR 1111 1111 ---- 1111 0000 0000 0000 -000 00-- --10 xxxx xxxx ---0 0001 0000 00-0000 0000 1111 1111 0000 0000 Value on all other Resets 1111 1111 ---- 1111 0000 0000 0000 -000 00-- --10 uuuu uuuu ---0 0001 0000 00-0000 0000 1111 1111 0000 0000
MC1OUT RC7 -- SR1 WCOL TRISC7 C1VREN
x = unknown, u = unchanged, - = unimplemented locations read as `0'. Shaded cells are not used by PORTC. PIC16F687/PIC16F689/PIC16F690 only. PIC16F685/PIC16F690 only.
DS41262D-page 80
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
5.0 TIMER0 MODULE
5.1 Timer0 Operation
The Timer0 module is an 8-bit timer/counter with the following features: * * * * * 8-bit timer/counter register (TMR0) 8-bit prescaler (shared with Watchdog Timer) Programmable internal or external clock source Programmable external clock edge selection Interrupt on overflow When used as a timer, the Timer0 module can be used as either an 8-bit timer or an 8-bit counter.
5.1.1
8-BIT TIMER MODE
When used as a timer, the Timer0 module will increment every instruction cycle (without prescaler). Timer mode is selected by clearing the T0CS bit of the OPTION register to `0'. When TMR0 is written, the increment is inhibited for two instruction cycles immediately following the write. Note: The value written to the TMR0 register can be adjusted, in order to account for the two instruction cycle delay when TMR0 is written.
Figure 5-1 is a block diagram of the Timer0 module.
5.1.2
8-BIT COUNTER MODE
When used as a counter, the Timer0 module will increment on every rising or falling edge of the T0CKI pin. The incrementing edge is determined by the T0SE bit of the OPTION register. Counter mode is selected by setting the T0CS bit of the OPTION register to `1'.
FIGURE 5-1:
FOSC/4
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
Data Bus 0 1 1 T0CKI pin T0SE T0CS 1 8 0 0 8-bit Prescaler PSA Set Flag bit T0IF on Overflow Sync 2 cycles TMR0 8
WDTE SWDTEN
PSA
PS<2:0> 16-bit Prescaler 31 kHz INTOSC Watchdog Timer WDTPS<3:0>
Note 1: 2: 3: T0SE, T0CS, PSA, PS<2:0> are bits in the OPTION register. SWDTEN and WDTPS<3:0> are bits in the WDTCON register. WDTE bit is in the Configuration Word register.
1 WDT Time-out 0
16 PSA
(c) 2007 Microchip Technology Inc.
DS41262D-page 81
PIC16F631/677/685/687/689/690
5.1.3 SOFTWARE PROGRAMMABLE PRESCALER
A single software programmable prescaler is available for use with either Timer0 or the Watchdog Timer (WDT), but not both simultaneously. The prescaler assignment is controlled by the PSA bit of the OPTION register. To assign the prescaler to Timer0, the PSA bit must be cleared to a `0'. There are 8 prescaler options for the Timer0 module ranging from 1:2 to 1:256. The prescale values are selectable via the PS<2:0> bits of the OPTION register. In order to have a 1:1 prescaler value for the Timer0 module, the prescaler must be assigned to the WDT module. The prescaler is not readable or writable. When the prescaler is assigned to the Timer0 module, all instructions writing to the TMR0 register will clear the prescaler. When the prescaler is assigned to WDT, a CLRWDT instruction will clear the prescaler along with the WDT. When changing the prescaler assignment from the WDT to the Timer0 module, the following instruction sequence must be executed (see Example 5-2).
EXAMPLE 5-2:
CLRWDT
CHANGING PRESCALER (WDT TIMER0)
;Clear WDT and ;prescaler BANKSEL OPTION_REG ; MOVLW b'11110000' ;Mask TMR0 select and ANDWF OPTION_REG,W ; prescaler bits IORLW b'00000011' ;Set prescale to 1:16 MOVWF OPTION_REG ;
5.1.4
TIMER0 INTERRUPT
5.1.3.1
Switching Prescaler Between Timer0 and WDT Modules
Timer0 will generate an interrupt when the TMR0 register overflows from FFh to 00h. The T0IF interrupt flag bit of the INTCON register is set every time the TMR0 register overflows, regardless of whether or not the Timer0 interrupt is enabled. The T0IF bit must be cleared in software. The Timer0 interrupt enable is the T0IE bit of the INTCON register. Note: The Timer0 interrupt cannot wake the processor from Sleep since the timer is frozen during Sleep.
As a result of having the prescaler assigned to either Timer0 or the WDT, it is possible to generate an unintended device Reset when switching prescaler values. When changing the prescaler assignment from Timer0 to the WDT module, the instruction sequence shown in Example 5-1, must be executed.
5.1.5
USING TIMER0 WITH AN EXTERNAL CLOCK
EXAMPLE 5-1:
BANKSEL CLRWDT CLRF BANKSEL BSF CLRWDT MOVLW ANDWF IORLW MOVWF TMR0 TMR0
CHANGING PRESCALER (TIMER0 WDT)
; ;Clear WDT ;Clear TMR0 and ; prescaler ; ;Select WDT ; ; ;Mask prescaler ; bits ;Set WDT prescaler ; to 1:32
When Timer0 is in Counter mode, the synchronization of the T0CKI input and the Timer0 register is accomplished by sampling the prescaler output on the Q2 and Q4 cycles of the internal phase clocks. Therefore, the high and low periods of the external clock source must meet the timing requirements as shown in Section 17.0 "Electrical Specifications".
OPTION_REG OPTION_REG,PSA
b'11111000' OPTION_REG,W b'00000101' OPTION_REG
DS41262D-page 82
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 5-1:
R/W-1 RABPU bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
OPTION_REG: OPTION REGISTER
R/W-1 INTEDG R/W-1 T0CS R/W-1 T0SE R/W-1 PSA R/W-1 PS2 R/W-1 PS1 R/W-1 PS0 bit 0
RABPU: PORTA/PORTB Pull-up Enable bit 1 = PORTA/PORTB pull-ups are disabled 0 = PORTA/PORTB pull-ups are enabled by individual PORT latch values INTEDG: Interrupt Edge Select bit 1 = Interrupt on rising edge of INT pin 0 = Interrupt on falling edge of INT pin T0CS: TMR0 Clock Source Select bit 1 = Transition on T0CKI pin 0 = Internal instruction cycle clock (FOSC/4) T0SE: TMR0 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: Prescaler Assignment bit 1 = Prescaler is assigned to the WDT 0 = Prescaler is assigned to the Timer0 module PS<2:0>: Prescaler Rate Select bits
BIT VALUE 000 001 010 011 100 101 110 111 TMR0 RATE 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 WDT RATE 1:1 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128
bit 6
bit 5
bit 4
bit 3
bit 2-0
Note 1:
A dedicated 16-bit WDT postscaler is available. See Section 14.5 "Watchdog Timer (WDT)" for more information.
TABLE 5-1:
Name INTCON TMR0 TRISA
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0
Bit 7 GIE Bit 6 PEIE Bit 5 T0IE T0CS Bit 4 INTE T0SE Bit 3 RABIE PSA Bit 2 T0IF PS2 Bit 1 INTF PS1 Bit 0 Value on POR, BOR Value on all other Resets
RABIF 0000 0000 0000 0000 PS0 1111 1111 1111 1111 xxxx xxxx uuuu uuuu
OPTION_REG RABPU INTEDG -- --
Timer0 Module Register
TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111
Legend: - = Unimplemented locations, read as `0', u = unchanged, x = unknown. Shaded cells are not used by the Timer0 module.
(c) 2007 Microchip Technology Inc.
DS41262D-page 83
PIC16F631/677/685/687/689/690
6.0 TIMER1 MODULE WITH GATE CONTROL
6.1 Timer1 Operation
The Timer1 module is a 16-bit incrementing counter which is accessed through the TMR1H:TMR1L register pair. Writes to TMR1H or TMR1L directly update the counter. When used with an internal clock source, the module is a timer. When used with an external clock source, the module can be used as either a timer or counter.
The Timer1 module is a 16-bit timer/counter with the following features: * * * * * * * * * * * 16-bit timer/counter register pair (TMR1H:TMR1L) Programmable internal or external clock source 3-bit prescaler Optional LP oscillator Synchronous or asynchronous operation Timer1 gate (count enable) via comparator or T1G pin Interrupt on overflow Wake-up on overflow (external clock, Asynchronous mode only) Time base for the Capture/Compare function (PIC16F685/PIC16F690 only) Special Event Trigger (with ECCP) (PIC16F685/PIC16F690 only) Comparator output synchronization to Timer1 clock
6.2
Clock Source Selection
The TMR1CS bit of the T1CON register is used to select the clock source. When TMR1CS = 0, the clock source is FOSC/4. When TMR1CS = 1, the clock source is supplied externally.
Clock Source FOSC/4 T1CKI pin T1LPOSC
T1OSCEN x 0 1
FOSC Mode xxx xxx LP or INTOSCIO
TMR1CS 0 1 1
Figure 6-1 is a block diagram of the Timer1 module.
FIGURE 6-1:
TIMER1 BLOCK DIAGRAM
TMR1GE TMR1ON Set flag bit TMR1IF on Overflow To C2 Comparator module Timer1 Clock EN 0 Synchronized clock input
T1GINV
TMR1(1) TMR1H TMR1L
1
Oscillator
OSC1/T1CKI
* 1 FOSC/4 Internal Clock
T1SYNC Prescaler 1, 2, 4, 8 0 2 T1CKPS<1:0> TMR1CS 1 Synchronize det
(2)
OSC2/T1G
T1OSCEN FOSC = 100 FOSC = 000 T1GSS Sleep SYNCC2OUT 0
* Note 1: 2:
ST Buffer is low power type when using LP osc, or high speed type when using T1CKI. Timer1 register increments on rising edge. Synchronize does not operate while in Sleep.
DS41262D-page 84
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
6.2.1 INTERNAL CLOCK SOURCE
When the internal clock source is selected the TMR1H:TMR1L register pair will increment on multiples of FOSC as determined by the Timer1 prescaler. TRISA5 and TRISA4 bits are set when the Timer1 oscillator is enabled. RA5 and RA4 bits read as `0' and TRISA5 and TRISA4 bits read as `1'. Note: The oscillator requires a start-up and stabilization time before use. Thus, T1OSCEN should be set and a suitable delay observed prior to enabling Timer1.
6.2.2
EXTERNAL CLOCK SOURCE
When the external clock source is selected, the Timer1 module may work as a timer or a counter. When counting, Timer1 is incremented on the rising edge of the external clock input T1CKI. In addition, the Counter mode clock can be synchronized to the microcontroller system clock or run asynchronously. If an external clock oscillator is needed (and the microcontroller is using the INTOSC without CLKOUT), Timer1 can use the LP oscillator as a clock source. Note: In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge after any one or more of the following conditions: * * * * Timer1 enabled after POR reset Write to TMR1H or TMR1L Timer1 is disabled Timer1 is disabled (TMR1ON 0) when T1CKI is high then Timer1 is enabled (TMR1ON=1) when T1CKI is low.
6.5
Timer1 Operation in Asynchronous Counter Mode
If control bit T1SYNC of the T1CON register is set, the external clock input is not synchronized. The timer increments asynchronously to the internal phase clocks. If external clock source is selected then the timer will continue to run during Sleep and can generate an interrupt on overflow, which will wake-up the processor. However, special precautions in software are needed to read/write the timer (see Section 6.5.1 "Reading and Writing Timer1 in Asynchronous Counter Mode"). Note: When switching from synchronous to asynchronous operation, it is possible to skip an increment. When switching from asynchronous to synchronous operation, it is possible to produce an additional increment.
Note:
See Figure 6-2
6.5.1
6.3
Timer1 Prescaler
READING AND WRITING TIMER1 IN ASYNCHRONOUS COUNTER MODE
Timer1 has four prescaler options allowing 1, 2, 4 or 8 divisions of the clock input. The T1CKPS bits of the T1CON register control the prescale counter. The prescale counter is not directly readable or writable; however, the prescaler counter is cleared upon a write to TMR1H or TMR1L.
Reading TMR1H or TMR1L while the timer is running from an external asynchronous clock will ensure a valid read (taken care of in hardware). However, the user should keep in mind that reading the 16-bit timer in two 8-bit values itself, poses certain problems, since the timer may overflow between the reads. For writes, it is recommended that the user simply stop the timer and write the desired values. A write contention may occur by writing to the timer registers, while the register is incrementing. This may produce an unpredictable value in the TMR1H:TMR1L register pair.
6.4
Timer1 Oscillator
A low-power 32.768 kHz crystal oscillator is built-in between pins OSC1 (input) and OSC2 (amplifier output). The oscillator is enabled by setting the T1OSCEN control bit of the T1CON register. The oscillator will continue to run during Sleep. The Timer1 oscillator is shared with the system LP oscillator. Thus, Timer1 can use this mode only when the primary system clock is derived from the internal oscillator or when the oscillator is in the LP mode. The user must provide a software time delay to ensure proper oscillator start-up.
6.6
Timer1 Gate
Timer1 gate source is software configurable to be the T1G pin or the output of Comparator C2. This allows the device to directly time external events using T1G or analog events using Comparator C2. See the CM2CON1 register (Register 8-3) for selecting the Timer1 gate source. This feature can simplify the software for a Delta-Sigma A/D converter and many other applications. For more information on Delta-Sigma A/D converters, see the Microchip web site (www.microchip.com).
(c) 2007 Microchip Technology Inc.
DS41262D-page 85
PIC16F631/677/685/687/689/690
Note: TMR1GE bit of the T1CON register must be set to use either T1G or C2OUT as the Timer1 gate source. See the CM2CON1 register (Register 8-3) for more information on selecting the Timer1 gate source. In Compare mode, an event is triggered when the value CCPR1H:CCPR1L register pair matches the value in the TMR1H:TMR1L register pair. This event can be a Special Event Trigger. For more information, see Section 11.0 "Enhanced Capture/Compare/PWM Module".
Timer1 gate can be inverted using the T1GINV bit of the T1CON register, whether it originates from the T1G pin or Comparator C2 output. This configures Timer1 to measure either the active-high or active-low time between events.
6.10
ECCP Special Event Trigger
6.7
Timer1 Interrupt
When the ECCP is configured to trigger a special event, the trigger will clear the TMR1H:TMR1L register pair. This special event does not cause a Timer1 interrupt. The ECCP module may still be configured to generate a ECCP interrupt. In this mode of operation, the CCPR1H:CCPR1L register pair becomes the period register for Timer1. Timer1 should be synchronized to the FOSC to utilize the Special Event Trigger. Asynchronous operation of Timer1 can cause a Special Event Trigger to be missed. In the event that a write to TMR1H or TMR1L coincides with a Special Event Trigger from the ECCP, the write will take precedence. For more information, see Section 11.2.4 "Special Event Trigger".
The Timer1 register pair (TMR1H:TMR1L) increments to FFFFh and rolls over to 0000h. When Timer1 rolls over, the Timer1 interrupt flag bit of the PIR1 register is set. To enable the interrupt on rollover, you must set these bits: * * * * TMR1ON bit of the T1CON register TMR1IE bit of the PIE1 register PEIE bit of the INTCON register GIE bit of the INTCON register
The interrupt is cleared by clearing the TMR1IF bit in the Interrupt Service Routine. Note: The TMR1H:TTMR1L register pair and the TMR1IF bit should be cleared before enabling interrupts.
6.11
Comparator Synchronization
6.8
Timer1 Operation During Sleep
The same clock used to increment Timer1 can also be used to synchronize the comparator output. This feature is enabled in the Comparator module. When using the comparator for Timer1 gate, the comparator output should be synchronized to Timer1. This ensures Timer1 does not miss an increment if the comparator changes. For more information, see Section 8.8.2 "Synchronizing Comparator C2 output to Timer1".
Timer1 can only operate during Sleep when setup in Asynchronous Counter mode. In this mode, an external crystal or clock source can be used to increment the counter. To set up the timer to wake the device: * * * * * * TMR1ON bit of the T1CON register must be set TMR1IE bit of the PIE1 register must be set PEIE bit of the INTCON register must be set T1SYNC bit of the T1CON register must be set TMR1CS bit of the T1CON register must be set T1OSCEN bit of the T1CON register (can be set)
The device will wake-up on an overflow and execute the next instructions. If the GIE bit of the INTCON register is set, the device will call the Interrupt Service Routine (0004h).
6.9
ECCP Capture/Compare Time Base
The ECCP module uses the TMR1H:TMR1L register pair as the time base when operating in Capture or Compare mode. In Capture mode, the value in the TMR1H:TMR1L register pair is copied into the CCPR1H:CCPR1L register pair on a configured event.
DS41262D-page 86
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 6-2:
T1CKI = 1 when TMR1 Enabled
TIMER1 INCREMENTING EDGE
T1CKI = 0 when TMR1 Enabled Note 1: 2: Arrows indicate counter increments. In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock.
(c) 2007 Microchip Technology Inc.
DS41262D-page 87
PIC16F631/677/685/687/689/690
6.12 Timer1 Control Register
The Timer1 Control register (T1CON), shown in Register 6-1, is used to control Timer1 and select the various features of the Timer1 module.
REGISTER 6-1:
R/W-0 T1GINV bit 7 Legend: R = Readable bit -n = Value at POR bit 7
(1)
T1CON: TIMER 1 CONTROL REGISTER
R/W-0 R/W-0
(2)
R/W-0 T1CKPS0
R/W-0 T1OSCEN
R/W-0 T1SYNC
R/W-0 TMR1CS
R/W-0 TMR1ON bit 0
TMR1GE
T1CKPS1
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
T1GINV: Timer1 Gate Invert bit(1) 1 = Timer1 gate is active high (Timer1 counts when gate is high) 0 = Timer1 gate is active low (Timer1 counts when gate is low) TMR1GE: Timer1 Gate Enable bit(2) If TMR1ON = 0: This bit is ignored If TMR1ON = 1: 1 = Timer1 is on if Timer1 gate is not active 0 = Timer1 is on T1CKPS<1:0>: 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: LP Oscillator Enable Control bit If INTOSC without CLKOUT oscillator is active: 1 = LP oscillator is enabled for Timer1 clock 0 = LP oscillator is off Else: This bit is ignored T1SYNC: Timer1 External Clock Input Synchronization Control bit TMR1CS = 1: 1 = Do not synchronize external clock input 0 = Synchronize external clock input TMR1CS = 0: This bit is ignored. Timer1 uses the internal clock TMR1CS: Timer1 Clock Source Select bit 1 = External clock from T1CKI pin (on the rising edge) 0 = Internal clock (FOSC/4) TMR1ON: Timer1 On bit 1 = Enables Timer1 0 = Stops Timer1 T1GINV bit inverts the Timer1 gate logic, regardless of source. TMR1GE bit must be set to use either T1G pin or C2OUT, as selected by the T1GSS bit of the CM2CON1 register, as a Timer1 gate source.
bit 6
bit 5-4
bit 3
bit 2
bit 1
bit 0
Note 1: 2:
DS41262D-page 88
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 6-1:
Name CM2CON1 INTCON PIE1 PIR1 TMR1H TMR1L T1CON Legend: Bit 7 MC1OUT GIE
SUMMARY OF REGISTERS ASSOCIATED WITH TIMER1
Bit 6 MC2OUT PEIE Bit 5 -- T0IE Bit 4 -- INTE Bit 3 -- RABIE Bit 2 -- T0IF Bit 1 T1GSS INTF Bit 0 C2SYNC RABIF Value on POR, BOR ---- --10 0000 0000 Value on all other Resets ---- --10 0000 0000
-- --
ADIE ADIF
RCIE RCIF
TXIE TXIF
SSPIE SSPIF
CCP1IE CCP1IF
TMR2IE TMR2IF
TMR1IE TMR1IF
-000 0000 -000 0000
xxxx xxxx xxxx xxxx
-000 0000 -000 0000
uuuu uuuu uuuu uuuu uuuu uuuu
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register Holding Register for the Least Significant Byte of the 16-bit TMR1 Register T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON
0000 0000
x = unknown, u = unchanged, -- = unimplemented, read as `0'. Shaded cells are not used by the Timer1 module.
(c) 2007 Microchip Technology Inc.
DS41262D-page 89
PIC16F631/677/685/687/689/690
NOTES:
DS41262D-page 90
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
7.0 TIMER2 MODULE
The Timer2 module is an eight-bit timer with the following features: * * * * * 8-bit timer register (TMR2) 8-bit period register (PR2) Interrupt on TMR2 match with PR2 Software programmable prescaler (1:1, 1:4, 1:16) Software programmable postscaler (1:1 to 1:16) The TMR2 and PR2 registers are both fully readable and writable. On any Reset, the TMR2 register is set to 00h and the PR2 register is set to FFh. Timer2 is turned on by setting the TMR2ON bit in the T2CON register to a `1'. Timer2 is turned off by clearing the TMR2ON bit to a `0'. The Timer2 prescaler is controlled by the T2CKPS bits in the T2CON register. The Timer2 postscaler is controlled by the TOUTPS bits in the T2CON register. The prescaler and postscaler counters are cleared when: * A write to TMR2 occurs. * A write to T2CON occurs. * Any device Reset occurs (Power-on Reset, MCLR Reset, Watchdog Timer Reset or Brown-out Reset). Note: TMR2 is not cleared when T2CON is written.
See Figure 7-1 for a block diagram of Timer2.
7.1
Timer2 Operation
The clock input to the Timer2 module is the system instruction clock (FOSC/4). The clock is fed into the Timer2 prescaler, which has prescale options of 1:1, 1:4 or 1:16. The output of the prescaler is then used to increment the TMR2 register. The values of TMR2 and PR2 are constantly compared to determine when they match. TMR2 will increment from 00h until it matches the value in PR2. When a match occurs, two things happen: * TMR2 is reset to 00h on the next increment cycle. * The Timer2 postscaler is incremented The match output of the Timer2/PR2 comparator is fed into the Timer2 postscaler. The postscaler has postscale options of 1:1 to 1:16 inclusive. The output of the Timer2 postscaler is used to set the TMR2IF interrupt flag bit in the PIR1 register.
FIGURE 7-1:
TIMER2 BLOCK DIAGRAM
TMR2 Output Sets Flag bit TMR2IF
FOSC/4
Prescaler 1:1, 1:4, 1:16 2 T2CKPS<1:0>
TMR2
Reset
Comparator EQ PR2
Postscaler 1:1 to 1:16 4 TOUTPS<3:0>
(c) 2007 Microchip Technology Inc.
DS41262D-page 91
PIC16F631/677/685/687/689/690
REGISTER 7-1:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7 bit 6-3 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
T2CON: TIMER 2 CONTROL REGISTER(1)
R/W-0 R/W-0 TOUTPS2 R/W-0 TOUTPS1 R/W-0 TOUTPS0 R/W-0 TMR2ON R/W-0 T2CKPS1 R/W-0 T2CKPS0 bit 0
TOUTPS3
Unimplemented: Read as `0' TOUTPS<3:0>: Timer2 Output Postscaler Select bits 0000 = 1:1 Postscaler 0001 = 1:2 Postscaler 0010 = 1:3 Postscaler 0011 = 1:4 Postscaler 0100 = 1:5 Postscaler 0101 = 1:6 Postscaler 0110 = 1:7 Postscaler 0111 = 1:8 Postscaler 1000 = 1:9 Postscaler 1001 = 1:10 Postscaler 1010 = 1:11 Postscaler 1011 = 1:12 Postscaler 1100 = 1:13 Postscaler 1101 = 1:14 Postscaler 1110 = 1:15 Postscaler 1111 = 1:16 Postscaler TMR2ON: Timer2 On bit 1 = Timer2 is on 0 = Timer2 is off T2CKPS<1:0>: Timer2 Clock Prescale Select bits 00 = Prescaler is 1 01 = Prescaler is 4 1x = Prescaler is 16 PIC16F685/PIC16F690 only.
bit 2
bit 1-0
Note 1:
TABLE 7-1:
Name INTCON PIE1 PIR1 PR2 TMR2 T2CON Legend: Note 1: Bit 7 GIE -- --
SUMMARY OF ASSOCIATED TIMER2(1) REGISTERS
Bit 6 PEIE ADIE ADIF Bit 5 T0IE RCIE RCIF Bit 4 INTE TXIE TXIF Bit 3 RABIE SSPIE SSPIF Bit 2 T0IF CCP1IE CCP1IF Bit 1 INTF TMR2IE TMR2IF Bit 0 RABIF TMR1IE TMR1IF Value on POR, BOR 0000 000x -000 0000 -000 0000 1111 1111 0000 0000 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 Value on all other Resets 0000 000x -000 0000 -000 0000 1111 1111 0000 0000 -000 0000
Timer2 Module Period Register Holding Register for the 8-bit TMR2 Register -- TOUTPS3 TOUTPS2 TOUTPS1
x = unknown, u = unchanged, -- = unimplemented read as `0'. Shaded cells are not used for Timer2 module. PIC16F685/PIC16F690 only.
DS41262D-page 92
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
8.0 COMPARATOR MODULE
FIGURE 8-1:
VIN+ VIN-
SINGLE COMPARATOR
+ - Output
Comparators are used to interface analog circuits to a digital circuit by comparing two analog voltages and providing a digital indication of their relative magnitudes. The comparators are very useful mixed signal building blocks because they provide analog functionality independent of program execution. The Analog Comparator module includes the following features: * * * * * * * * * * * Independent comparator control Programmable input selection Comparator output is available internally/externally Programmable output polarity Interrupt-on-change Wake-up from Sleep PWM shutdown Timer1 gate (count enable) Output synchronization to Timer1 clock input SR Latch Programmable and fixed voltage reference Note: Only Comparator C2 can be linked to Timer1.
VINVIN+
Output
Note:
The black areas of the output of the comparator represents the uncertainty due to input offsets and response time.
8.1
Comparator Overview
A single comparator is shown in Figure 8-1 along with the relationship between the analog input levels and the digital output. When the analog voltage at VIN+ is less than the analog voltage at VIN-, the output of the comparator is a digital low level. When the analog voltage at VIN+ is greater than the analog voltage at VIN-, the output of the comparator is a digital high level.
(c) 2007 Microchip Technology Inc.
DS41262D-page 93
PIC16F631/677/685/687/689/690
FIGURE 8-2: COMPARATOR C1 SIMPLIFIED BLOCK DIAGRAM
C1CH<1:0> 2 D C12IN0C12IN1C12IN2C12IN30 1 MUX 2 3 C1ON(1) C1R C1IN+ FixedRef CVREF C1VREN 0 MUX 1 0 MUX 1 C1VIN- C1VIN+ C1 + C1POL Note 1: 2: 3: When C1ON = 0, the C1 comparator will produce a `0' output to the XOR Gate. Q1 and Q3 are phases of the four-phase system clock (FOSC). Q1 is held high during Sleep mode. C1OUT C1OUT (to SR latch) Q1 EN Q C1POL To Data Bus RD_CM1CON0 Set C1IF D Q3*RD_CM1CON0 Q EN CL NRESET
To other peripherals
FIGURE 8-3:
COMPARATOR C2 SIMPLIFIED BLOCK DIAGRAM
C2POL D Q1 EN Q To Data Bus RD_CM2CON0 Set C2IF 2 D C2ON(1) C2VINC2VIN+ C2 C2OUT C2SYNC C2POL D Q Q3*RD_CM2CON0 Q EN CL NRESET
C2CH<1:0>
C12IN0C12IN1C2IN2C2IN3-
0 1 MUX 2 3
C2R C2IN+ FixedRef CVREF C2VREN 0 MUX 1 0 MUX 1
0 MUX 1
SYNCC2OUT to Timer1 Gate, SR latch and other peripherals
From TMR1 Clock
Note 1: 2: 3:
When C2ON = 0, the C2 comparator will produce a `0' output to the XOR Gate. Q1 and Q3 are phases of the four-phase system clock (FOSC). Q1 is held high during Sleep mode.
DS41262D-page 94
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
8.2 Comparator Control
8.2.4
Each comparator has a separate control and Configuration register: CM1CON0 for Comparator C1 and CM2CON0 for Comparator C2. In addition, Comparator C2 has a second control register, CM2CON1, for controlling the interaction with Timer1 and simultaneous reading of both comparator outputs. The CM1CON0 and CM2CON0 registers (see Registers 8-1 and 8-2, respectively) contain the control and Status bits for the following: * * * * * Enable Input selection Reference selection Output selection Output polarity
COMPARATOR OUTPUT SELECTION
The output of the comparator can be monitored by reading either the CxOUT bit of the CMxCON0 register or the MCxOUT bit of the CM2CON1 register. In order to make the output available for an external connection, the following conditions must be true: * CxOE bit of the CMxCON0 register must be set * Corresponding TRIS bit must be cleared * CxON bit of the CMxCON0 register must be set Note 1: The CxOE bit overrides the PORT data latch. Setting the CxON has no impact on the port override. 2: The internal output of the comparator is latched with each instruction cycle. Unless otherwise specified, external outputs are not latched.
8.2.1
COMPARATOR ENABLE 8.2.5
Setting the CxON bit of the CMxCON0 register enables the comparator for operation. Clearing the CxON bit disables the comparator resulting in minimum current consumption.
COMPARATOR OUTPUT POLARITY
8.2.2
COMPARATOR INPUT SELECTION
The CxCH<1:0> bits of the CMxCON0 register direct one of four analog input pins to the comparator inverting input. Note: To use CxIN+ and C12INx- pins as analog inputs, the appropriate bits must be set in the ANSEL register and the corresponding TRIS bits must also be set to disable the output drivers.
Inverting the output of the comparator is functionally equivalent to swapping the comparator inputs. The polarity of the comparator output can be inverted by setting the CxPOL bit of the CMxCON0 register. Clearing the CxPOL bit results in a non-inverted output. Table 8-1 shows the output state versus input conditions, including polarity control.
TABLE 8-1:
COMPARATOR OUTPUT STATE VS. INPUT CONDITIONS
CxPOL 0 0 1 1 CxOUT 0 1 1 0
Input Condition CxVIN- > CxVIN+ CxVIN- < CxVIN+ CxVIN- > CxVIN+ CxVIN- < CxVIN+
8.2.3
COMPARATOR REFERENCE SELECTION
Setting the CxR bit of the CMxCON0 register directs an internal voltage reference or an analog input pin to the non-inverting input of the comparator. See Section 8.9 "Comparator SR Latch" for more information on the Internal Voltage Reference module.
8.3
Comparator Response Time
The comparator output is indeterminate for a period of time after the change of an input source or the selection of a new reference voltage. This period is referred to as the response time. The response time of the comparator differs from the settling time of the voltage reference. Therefore, both of these times must be considered when determining the total response time to a comparator input change. See the Comparator and Voltage Reference Specifications in Section 17.0 "Electrical Specifications" for more details.
(c) 2007 Microchip Technology Inc.
DS41262D-page 95
PIC16F631/677/685/687/689/690
8.4 Comparator Interrupt Operation
FIGURE 8-4:
The comparator interrupt flag can be set whenever there is a change in the output value of the comparator. Changes are recognized by means of a mismatch circuit which consists of two latches and an exclusiveor gate (see Figure 8-2 and Figure 8-3). One latch is updated with the comparator output level when the CMxCON0 register is read. This latch retains the value until the next read of the CMxCON0 register or the occurrence of a Reset. The other latch of the mismatch circuit is updated on every Q1 system clock. A mismatch condition will occur when a comparator output change is clocked through the second latch on the Q1 clock cycle. At this point the two mismatch latches have opposite output levels which is detected by the exclusive-or gate and fed to the interrupt circuitry. The mismatch condition persists until either the CMxCON0 register is read or the comparator output returns to the previous state. Note 1: A write operation to the CMxCON0 register will also clear the mismatch condition because all writes include a read operation at the beginning of the write cycle. 2: Comparator interrupts will operate correctly regardless of the state of CxOE. The comparator interrupt is set by the mismatch edge and not the mismatch level. This means that the interrupt flag can be reset without the additional step of reading or writing the CMxCON0 register to clear the mismatch registers. When the mismatch registers are cleared, an interrupt will occur upon the comparator's return to the previous state, otherwise no interrupt will be generated. Software will need to maintain information about the status of the comparator output, as read from the CMxCON0 register, or CM2CON1 register, to determine the actual change that has occurred. The CxIF bit of the PIR1 register is the comparator interrupt flag. This bit must be reset in software by clearing it to `0'. Since it is also possible to write a '1' to this register, an interrupt can be generated. The CxIE bit of the PIE1 register and the PEIE and GIE bits of the INTCON register must all be set to enable comparator interrupts. If any of these bits are cleared, the interrupt is not enabled, although the CxIF bit of the PIR1 register will still be set if an interrupt condition occurs. Note 1: If a change in the CMxCON0 register (CxOUT) should occur when a read operation is being executed (start of the Q2 cycle), then the CxIF of the PIR1 register interrupt flag may not get set. 2: When either comparator is first enabled, bias circuitry in the Comparator module may cause an invalid output from the comparator until the bias circuitry is stable. Allow about 1 s for bias settling then clear the mismatch condition and interrupt flags before enabling comparator interrupts.
COMPARATOR INTERRUPT TIMING W/O CMxCON0 READ
Q1 Q3 CxIN+ Cxout Set CxIF (edge) CxIF reset by software TRT
FIGURE 8-5:
COMPARATOR INTERRUPT TIMING WITH CMxCON0 READ
Q1 Q3 CxIN+ Cxout Set CxIF (edge) CxIF cleared by CMxCON0 read reset by software TRT
DS41262D-page 96
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
8.5 Operation During Sleep
The comparator, if enabled before entering Sleep mode, remains active during Sleep. The additional current consumed by the comparator is shown separately in the Section 17.0 "Electrical Specifications". If the comparator is not used to wake the device, power consumption can be minimized while in Sleep mode by turning off the comparator. Each comparator is turned off by clearing the CxON bit of the CMxCON0 register. A change to the comparator output can wake-up the device from Sleep. To enable the comparator to wake the device from Sleep, the CxIE bit of the PIE1 register and the PEIE bit of the INTCON register must be set. The instruction following the Sleep instruction always executes following a wake from Sleep. If the GIE bit of the INTCON register is also set, the device will then execute the Interrupt Service Routine.
8.6
Effects of a Reset
A device Reset forces the CMxCON0 and CM2CON1 registers to their Reset states. This forces both comparators and the voltage references to their OFF states.
(c) 2007 Microchip Technology Inc.
DS41262D-page 97
PIC16F631/677/685/687/689/690
REGISTER 8-1:
R/W-0 C1ON bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
CM1CON0: COMPARATOR C1 CONTROL REGISTER 0
R-0 C1OUT R/W-0 C1OE R/W-0 C1POL U-0 -- R/W-0 C1R R/W-0 C1CH1 R/W-0 C1CH0 bit 0
C1ON: Comparator C1 Enable bit 1 = Comparator C1 is enabled 0 = Comparator C1 is disabled C1OUT: Comparator C1 Output bit If C1POL = 1 (inverted polarity): C1OUT = 0 when C1VIN+ > C1VINC1OUT = 1 when C1VIN+ < C1VINIf C1POL = 0 (non-inverted polarity): C1OUT = 1 when C1VIN+ > C1VINC1OUT = 0 when C1VIN+ < C1VINC1OE: Comparator C1 Output Enable bit 1 = C1OUT is present on the C1OUT pin(1) 0 = C1OUT is internal only C1POL: Comparator C1 Output Polarity Select bit 1 = C1OUT logic is inverted 0 = C1OUT logic is not inverted Unimplemented: Read as `0' C1R: Comparator C1 Reference Select bit (non-inverting input) 1 = C1VIN+ connects to C1VREF output 0 = C1VIN+ connects to C1IN+ pin C1CH<1:0>: Comparator C1 Channel Select bit 00 = C1VIN- of C1 connects to C12IN0- pin 01 = C1VIN- of C1 connects to C12IN1- pin 10 = C1VIN- of C1 connects to C12IN2- pin 11 = C1VIN- of C1 connects to C12IN3- pin Comparator output requires the following three conditions: C1OE = 1, C1ON = 1 and corresponding PORT TRIS bit = 0.
bit 6
bit 5
bit 4
bit 3 bit 2
bit 1-0
Note 1:
DS41262D-page 98
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 8-2:
R/W-0 C2ON bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
CM2CON0: COMPARATOR C2 CONTROL REGISTER 0
R-0 C2OUT R/W-0 C2OE R/W-0 C2POL U-0 -- R/W-0 C2R R/W-0 C2CH1 R/W-0 C2CH0 bit 0
C2ON: Comparator C2 Enable bit 1 = Comparator C2 is enabled 0 = Comparator C2 is disabled C2OUT: Comparator C2 Output bit If C2POL = 1 (inverted polarity): C2OUT = 0 when C2VIN+ > C2VINC2OUT = 1 when C2VIN+ < C2VINIf C2POL = 0 (non-inverted polarity): C2OUT = 1 when C2VIN+ > C2VINC2OUT = 0 when C2VIN+ < C2VINC2OE: Comparator C2 Output Enable bit 1 = C2OUT is present on C2OUT pin(1) 0 = C2OUT is internal only C1POL: Comparator C1 Output Polarity Select bit 1 = C1OUT logic is inverted 0 = C1OUT logic is not inverted Unimplemented: Read as `0' C2R: Comparator C2 Reference Select bits (non-inverting input) 1 = C2VIN+ connects to C2VREF 0 = C2VIN+ connects to C2IN+ pin C2CH<1:0>: Comparator C2 Channel Select bits 00 = C2VIN- of C2 connects to C12IN0- pin 01 = C2VIN- of C2 connects to C12IN1- pin 10 = C2VIN- of C2 connects to C12IN2- pin 11 = C2VIN- of C2 connects to C12IN3- pin Comparator output requires the following three conditions: C2OE = 1, C2ON = 1 and corresponding PORT TRIS bit = 0.
bit 6
bit 5
bit 4
bit 3 bit 2
bit 1-0
Note 1:
(c) 2007 Microchip Technology Inc.
DS41262D-page 99
PIC16F631/677/685/687/689/690
8.7 Analog Input Connection Considerations
Note 1: When reading a PORT register, all pins configured as analog inputs will read as a `0'. Pins configured as digital inputs will convert as an analog input, according to the 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.
A simplified circuit for an analog input is shown in Figure 8-6. Since the analog input pins share their connection with a digital input, they have reverse biased ESD protection 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 latch-up may occur. A maximum source impedance of 10 k is recommended for the analog sources. Also, any external component connected to an analog input pin, such as a capacitor or a Zener diode, should have very little leakage current to minimize inaccuracies introduced.
FIGURE 8-6:
ANALOG INPUT MODEL
VDD
Rs < 10K AIN VA CPIN 5 pF
VT 0.6V
RIC To ADC Input
VT 0.6V
ILEAKAGE 500 nA
Vss Legend: CPIN = Input Capacitance ILEAKAGE = Leakage Current at the pin due to various junctions RIC = Interconnect Resistance = Source Impedance RS = Analog Voltage VA VT = Threshold Voltage
DS41262D-page 100
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
8.8 Additional Comparator Features
8.8.2
There are three additional comparator features: * Timer1 count enable (gate) * Synchronizing output with Timer1 * Simultaneous read of comparator outputs
SYNCHRONIZING COMPARATOR C2 OUTPUT TO TIMER1
8.8.1
COMPARATOR C2 GATING TIMER1
This feature can be used to time the duration or interval of analog events. Clearing the T1GSS bit of the CM2CON1 register will enable Timer1 to increment based on the output of Comparator C2. This requires that Timer1 is on and gating is enabled. See Section 6.0 "Timer1 Module with Gate Control" for details. It is recommended to synchronize the comparator with Timer1 by setting the C2SYNC bit when the comparator is used as the Timer1 gate source. This ensures Timer1 does not miss an increment if the comparator changes during an increment.
The Comparator C2 output can be synchronized with Timer1 by setting the C2SYNC bit of the CM2CON1 register. When enabled, the C2 output is latched on the falling edge of the Timer1 clock source. If a prescaler is used with Timer1, the comparator output is latched after the prescaling function. To prevent a race condition, the comparator output is latched on the falling edge of the Timer1 clock source and Timer1 increments on the rising edge of its clock source. See the Comparator Block Diagram (Figure 8-3) and the Timer1 Block Diagram (Figure 6-1) for more information.
8.8.3
SIMULTANEOUS COMPARATOR OUTPUT READ
The MC1OUT and MC2OUT bits of the CM2CON1 register are mirror copies of both comparator outputs. The ability to read both outputs simultaneously from a single register eliminates the timing skew of reading separate registers.
Note 1: Obtaining the status of C1OUT or C2OUT by reading CM2CON1 does not affect the comparator interrupt mismatch registers.
REGISTER 8-3:
R-0 MC1OUT bit 7 Legend: R = Readable bit -n = Value at POR bit 7 bit 6 bit 5-2 bit 1
CM2CON1: COMPARATOR C2 CONTROL REGISTER 1
R-0 MC2OUT U-0 -- U-0 -- U-0 -- U-0 -- R/W-1 T1GSS R/W-0 C2SYNC bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
MC1OUT: Mirror Copy of C1OUT bit MC2OUT: Mirror Copy of C2OUT bit Unimplemented: Read as `0' T1GSS: Timer1 Gate Source Select bit(1) 1 = Timer1 gate source is T1G 0 = Timer1 gate source is SYNCC2OUT. C2SYNC: Comparator C2 Output Synchronization bit(2) 1 = Output is synchronous to falling edge of Timer1 clock 0 = Output is asynchronous Refer to Section 6.6 "Timer1 Gate". Refer to Figure 8-3.
bit 0
Note 1: 2:
(c) 2007 Microchip Technology Inc.
DS41262D-page 101
PIC16F631/677/685/687/689/690
8.9 Comparator SR Latch
8.9.2 LATCH OUTPUT
The SR Latch module provides additional control of the comparator outputs. The module consists of a single SR latch and output multiplexers. The SR latch can be set, reset or toggled by the comparator outputs. The SR latch may also be set or reset, independent of comparator output, by control bits in the SRCON control register. The SR latch output multiplexers select whether the latch outputs or the comparator outputs are directed to the I/O port logic for eventual output to a pin. The SR<1:0> bits of the SRCON register control the latch output multiplexers and determine four possible output configurations. In these four configurations, the CxOUT I/O port logic is connected to: * * * * C1OUT and C2OUT C1OUT and SR latch Q C2OUT and SR latch Q SR latch Q and Q
8.9.1
LATCH OPERATION
The latch is a Set-Reset latch that does not depend on a clock source. Each of the Set and Reset inputs are active-high. Each latch input is connected to a comparator output and a software controlled pulse generator. The latch can be set by C1OUT or the PULSS bit of the SRCON register. The latch can be reset by C2OUT or the PULSR bit of the SRCON register. The latch is reset-dominant, therefore, if both Set and Reset inputs are high, the latch will go to the Reset state. Both the PULSS and PULSR bits are self resetting which means that a single write to either of the bits is all that is necessary to complete a latch set or reset operation.
After any Reset, the default output configuration is the unlatched C1OUT and C2OUT mode. This maintains compatibility with devices that do not have the SR latch feature. The applicable TRIS bits of the corresponding ports must be cleared to enable the port pin output drivers. Additionally, the CxOE comparator output enable bits of the CMxCON0 registers must be set in order to make the comparator or latch outputs available on the output pins. The latch configuration enable states are completely independent of the enable states for the comparators.
FIGURE 8-7:
SR LATCH SIMPLIFIED BLOCK DIAGRAM
SR0 C1OE
PULSS
Pulse Gen(2)
C1OUT (from comparator) C1SEN
S
Q
0 MUX 1
C1OUT pin(3)
SR Latch(1) SYNCC2OUT (from comparator) C2REN R Q 1 MUX 0 SR1
C2OE
C2OUT pin(3)
PULSR
Pulse Gen(2)
Note 1: 2: 3:
If R = 1 and S = 1 simultaneously, Q = 0, Q = 1 Pulse generator causes a 1/2 Q-state (1 Tosc) pulse width. Output shown for reference only. See I/O port pin block diagram for more detail.
DS41262D-page 102
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 8-4:
R/W-0 SR1(2) bit 7 Legend: R = Readable bit -n = Value at POR bit 7 S = Bit is set only W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
SRCON: SR LATCH CONTROL REGISTER
R/W-0 SR0(2) R/W-0 C1SEN R/W-0 C2REN R/S-0 PULSS R/S-0 PULSR U-0 -- U-0 -- bit 0
SR1: SR Latch Configuration bit(2) 1 = C2OUT pin is the latch Q output 0 = C2OUT pin is the C2 comparator output SR0: SR Latch Configuration bits(2) 1 = C1OUT pin is the latch Q output 0 = C1OUT pin is the Comparator C1 output C1SEN: C1 Set Enable bit 1 = C1 comparator output sets SR latch 0 = C1 comparator output has no effect on SR latch C2REN: C2 Reset Enable bit 1 = C2 comparator output resets SR latch 0 = C2 comparator output has no effect on SR latch PULSS: Pulse the SET Input of the SR Latch bit 1 = Triggers pulse generator to set SR latch. Bit is immediately reset by hardware. 0 = Does not trigger pulse generator PULSR: Pulse the Reset Input of the SR Latch bit 1 = Triggers pulse generator to reset SR latch. Bit is immediately reset by hardware. 0 = Does not trigger pulse generator Unimplemented: Read as `0' The CxOUT bit in the CMxCON0 register will always reflect the actual comparator output (not the level on the pin), regardless of the SR latch operation. To enable an SR latch output to the pin, the appropriate CxOE and TRIS bits must be properly configured.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1-0 Note 1: 2:
(c) 2007 Microchip Technology Inc.
DS41262D-page 103
PIC16F631/677/685/687/689/690
8.10 Comparator Voltage Reference
8.10.3 OUTPUT CLAMPED TO VSS
The comparator voltage reference module provides an internally generated voltage reference for the comparators. The following features are available: * * * * * Independent from Comparator operation Two 16-level voltage ranges Output clamped to VSS Ratiometric with VDD Fixed Reference (0.6) The CVREF output voltage can be set to VSS with no power consumption by configuring VRCON as follows: * VREN = 0 * VRR = 1 * VR<3:0> = 0000 This allows the comparator to detect a zero-crossing while not consuming additional CVREF module current.
The VRCON register (Register 8-5) controls the Voltage Reference module shown in Figure 8-8.
8.10.4
OUTPUT RATIOMETRIC TO VDD
8.10.1
INDEPENDENT OPERATION
The comparator voltage reference is independent of the comparator configuration. Setting the VREN bit of the VRCON register will enable the voltage reference.
The comparator voltage reference is VDD derived and therefore, the CVREF output changes with fluctuations in VDD. The tested absolute accuracy of the Comparator Voltage Reference can be found in Section 17.0 "Electrical Specifications".
8.10.2
OUTPUT VOLTAGE SELECTION
The CVREF voltage reference has 2 ranges with 16 voltage levels in each range. Range selection is controlled by the VRR bit of the VRCON register. The 16 levels are set with the VR<3:0> bits of the VRCON register.
The CVREF output voltage is determined by the following
equations:
EQUATION 8-1:
CVREF OUTPUT VOLTAGE
VRR = 1 (low range): CVREF = (VR<3:0>/24) x VDD VRR = 0 (high range): CVREF = (VDD/4) + (VR<3:0> x VDD/32) The full range of VSS to VDD cannot be realized due to the construction of the module. See Figure 8-8.
DS41262D-page 104
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
8.10.5 FIXED VOLTAGE REFERENCE 8.10.7
The fixed voltage reference is independent of VDD, with a nominal output voltage of 0.6V. This reference can be enabled by setting the VP6EN bit of the VRCON register to `1'. This reference is always enabled when the HFINTOSC oscillator is active.
VOLTAGE REFERENCE SELECTION
Multiplexers on the output of the Voltage Reference module enable selection of either the CVREF or fixed voltage reference for use by the comparators. Setting the C1VREN bit of the VRCON register enables current to flow in the CVREF voltage divider and selects the CVREF voltage for use by C1. Clearing the C1VREN bit selects the fixed voltage for use by C1. Setting the C2VREN bit of the VRCON register enables current to flow in the CVREF voltage divider and selects the CVREF voltage for use by C2. Clearing the C2VREN bit selects the fixed voltage for use by C2. When both the C1VREN and C2VREN bits are cleared, current flow in the CVREF voltage divider is disabled minimizing the power drain of the voltage reference peripheral.
8.10.6
FIXED VOLTAGE REFERENCE STABILIZATION PERIOD
When the Fixed Voltage Reference module is enabled, it will require some time for the reference and its amplifier circuits to stabilize. The user program must include a small delay routine to allow the module to settle. See the electrical specifications section for the minimum delay requirement.
FIGURE 8-8:
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
16 Stages 8R R R R R
VDD 8R 16-1 Analog MUX VRR
CVREF To Comparators and ADC module VR<3:0>(1) C1VREN C2VREN VP6EN Sleep HFINTOSC enable FixedRef To Comparators and ADC module 0.6V EN Fixed Voltage Reference
Note 1:
Care should be taken to ensure VREF remains within the comparator common mode input range. See Section 17.0 "Electrical Specifications" for more detail.
(c) 2007 Microchip Technology Inc.
DS41262D-page 105
PIC16F631/677/685/687/689/690
REGISTER 8-5:
R/W-0 C1VREN bit 7 Legend: R = Readable bit -n = Value at POR bit 7 S = Bit is set only W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
VRCON: VOLTAGE REFERENCE CONTROL REGISTER
R/W-0 C2VREN R/W-0 VRR R/W-0 VP6EN R/S-0 VR3 R/S-0 VR2 U-0 VR1 U-0 VR0 bit 0
C1VREN: Comparator C1 Voltage Reference Enable bit 1 = CVREF circuit powered on and routed to C1VREF input of Comparator C1 0 = 0.6 Volt constant reference routed to C1VREF input of Comparator C1 C2VREN: Comparator C2 Voltage Reference Enable bit 1 = CVREF circuit powered on and routed to C2VREF input of Comparator C2 0 = 0.6 Volt constant reference routed to C2VREF input of Comparator C2 VRR: Comparator Voltage Reference CVREF Range Selection bit 1 = Low Range 0 = High Range VP6EN: 0.6V Reference Enable bit 1 = Enabled 0 = Disabled VR<3:0>: Comparator Voltage Reference CVREF Value Selection 0 VR<3:0> 15 When VRR = 1: CVREF = (VR<3:0>/24) * VDD When VRR = 0: CVREF = VDD/4 + (VR<3:0>/32) * VDD
bit 6
bit 5
bit 4
bit 3-0
TABLE 8-2:
SUMMARY OF REGISTERS ASSOCIATED WITH THE COMPARATOR AND VOLTAGE REFERENCE MODULES
Bit 7 ANS7 C1ON C2ON Bit 6 ANS6 C1OUT C2OUT MC2OUT PEIE C2IE C2IF -- RC6 -- SR0 -- TRISC6 C2VREN Bit 5 ANS5 C1OE C2OE -- T0IE C1IE C1IF RA5 RC5 BGST C1SEN Bit 4 ANS4 C1POL C2POL -- INTE EEIE EEIF RA4 RC4 VRBB C2REN Bit 3 ANS3 -- -- -- RABIE -- -- RA3 RC3 VREN PULSS Bit 2 ANS2 C1R C2R -- T0IF -- -- RA2 RC2 VROE PULSR Bit 1 ANS1 C1CH1 C2CH1 T1GSS INTF -- -- RA1 RC1 CVROE -- TRISA1 TRISC1 VR1 Bit 0 ANS0 C1CH0 C2CH0 C2SYNC RABIF -- -- RA0 RC0 -- -- TRISA0 TRISC0 VR0 Value on POR, BOR 1111 1111 0000 -000 0000 -000 00-- --10 0000 000x 0000 ---0000-----xx xxxx xxxx xxxx --00 0000000 00---11 1111 1111 1111 0000 0000 Value on all other Resets 1111 1111 0000 0000 0000 -000 00-- --10 0000 000x 0000 ---0000-----uu uuuu uuuu uuuu --00 0000000 00---11 1111 1111 1111 0000 0000
Name ANSEL CM1CON0 CM2CON0 CM2CON1 INTCON PIE2 PIR2 PORTA PORTC REFCON SRCON TRISA TRISC VRCON Legend:
MC1OUT GIE OSFIE OSFIF -- RC7 -- SR1 -- TRISC7 C1VREN
TRISA5 TRISA4 TRISA3 TRISA2 TRISC5 TRISC4 TRISC3 TRISC2 VRR VP6EN VR3 VR2
x = unknown, u = unchanged, - = unimplemented, read as `0'. Shaded cells are not used for comparator.
DS41262D-page 106
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
9.0 ANALOG-TO-DIGITAL CONVERTER (ADC) MODULE
Figure 9-1 shows the block diagram of the ADC.
The Analog-to-Digital Converter (ADC) allows conversion of an analog input signal to a 10-bit binary representation of that signal. This device uses analog inputs, which are multiplexed into a single sample and hold circuit. The output of the sample and hold is connected to the input of the converter. The converter generates a 10-bit binary result via successive approximation and stores the conversion result into the ADC result registers (ADRESL and ADRESH). Note: The ADC module applies to PIC16F677/ PIC16F685/PIC16F687/PIC16F689/ PIC16F690 devices only.
The ADC voltage reference is software selectable to either VDD or a voltage applied to the external reference pins. The ADC can generate an interrupt upon completion of a conversion. This interrupt can be used to wake-up the device from Sleep.
FIGURE 9-1:
ADC BLOCK DIAGRAM
VDD VCFG = 0 VREF VCFG = 1
RA0/AN0/C1IN+/ICSPDAT/ULPWU RA1/AN1/C12IN0-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RA4/AN3/T1G/OSC2/CLKOUT RC0/AN4/C2IN+ RC1/AN5/C12IN1RC2/AN6/C12IN2-/P1D(1) RC3/AN7/C12IN3-/P1C(1) RC6/AN8/SS RC7/AN9/SDO
(2) (2)
ADC GO/DONE ADFM ADON VSS ADRESH 10 0 = Left Justify 1 = Right Justify 10 ADRESL
RB4/AN10/SDI/SDA(2) RB5/AN11/RX/DT(2) CVREF VP6 Reference
CHS
Note 1: 2: 3:
P1C and P1D available on PIC16F685/PIC16F690 only. SS, SDO, SDA, RX and DT available on PIC16F677/PIC16F687/PIC16F689/PIC16F690 only. ADC module applies to the PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 devices only.
(c) 2007 Microchip Technology Inc.
DS41262D-page 107
PIC16F631/677/685/687/689/690
9.1 ADC Configuration
9.1.3
ADC VOLTAGE REFERENCE
When configuring and using the ADC the following functions must be considered: * * * * * * Port configuration Channel selection ADC voltage reference selection ADC conversion clock source Interrupt control Results formatting
The VCFG bit of the ADCON0 register provides control of the positive voltage reference. The positive voltage reference can be either VDD or an external voltage source. The negative voltage reference is always connected to the ground reference.
9.1.4
CONVERSION CLOCK
The source of the conversion clock is software selectable via the ADCS bits of the ADCON1 register. There are seven possible clock options: * * * * * * * FOSC/2 FOSC/4 FOSC/8 FOSC/16 FOSC/32 FOSC/64 FRC (dedicated internal oscillator)
9.1.1
PORT CONFIGURATION
The ADC can be used to convert both analog and digital signals. When converting analog signals, the I/O pin should be configured for analog by setting the associated TRIS and ANSEL bits. See the corresponding port section for more information. Note: Analog voltages on any pin that is defined as a digital input may cause the input buffer to conduct excess current.
9.1.2
CHANNEL SELECTION
The time to complete one bit conversion is defined as TAD. One full 10-bit conversion requires 11 TAD periods as shown in Figure 9-2. For correct conversion, the appropriate TAD specification must be met. See A/D conversion requirements in Section 17.0 "Electrical Specifications" for more information. Table 9-1 gives examples of appropriate ADC clock selections. Note: Unless using the FRC, any changes in the system clock frequency will change the ADC clock frequency, which may adversely affect the ADC result.
The CHS bits of the ADCON0 register determine which channel is connected to the sample and hold circuit. When changing channels, a delay is required before starting the next conversion. Refer to Section 9.2 "ADC Operation" for more information.
DS41262D-page 108
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 9-1: ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES (VDD > 3.0V)
Device Frequency (FOSC) 20 MHz 100 ns 200 ns
(2) (2)
ADC Clock Period (TAD) ADC Clock Source FOSC/2 FOSC/4 FOSC/8 FOSC/16 FOSC/32 FOSC/64 FRC Legend: Note 1: 2: 3: 4: ADCS<2:0> 000 100 001 101 010 110 x11
8 MHz 250 ns 500 ns
(2) (2)
4 MHz 500 ns 1.0 s
(2) (2)
1 MHz 2.0 s 4.0 s 8.0 s(3) 16.0 s(3) 32.0 s(3) 64.0 s(3) 2-6 s(1,4)
400 ns(2) 800 ns(2) 1.6 s 3.2 s 2-6 s(1,4)
1.0 s(2) 2.0 s 4.0 s 8.0 s(3) 2-6 s(1,4)
2.0 s 4.0 s 8.0 s 2-6
(3)
16.0 s(3) s(1,4)
Shaded cells are outside of recommended range. The FRC source has a typical TAD time of 4 s for VDD > 3.0V. These values violate the minimum required TAD time. For faster conversion times, the selection of another clock source is recommended. When the device frequency is greater than 1 MHz, the FRC clock source is only recommended if the conversion will be performed during Sleep.
FIGURE 9-2:
ANALOG-TO-DIGITAL CONVERSION TAD CYCLES
TCY to TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Conversion Starts Holding Capacitor is disconnected from analog input (typically 100 ns) Set GO/DONE bit ADRESH and ADRESL registers are loaded, GO bit is cleared, ADIF bit is set, Holding capacitor is connected to analog input
9.1.5
INTERRUPTS
The ADC module allows for the ability to generate an interrupt upon completion of an Analog-to-Digital conversion. The ADC interrupt flag is the ADIF bit in the PIR1 register. The ADC interrupt enable is the ADIE bit in the PIE1 register. The ADIF bit must be cleared in software. Note: The ADIF bit is set at the completion of every conversion, regardless of whether or not the ADC interrupt is enabled.
This interrupt can be generated while the device is operating or while in Sleep. If the device is in Sleep, the interrupt will wake-up the device. Upon waking from Sleep, the next instruction following the SLEEP instruction is always executed. If the user is attempting to wake-up from Sleep and resume in-line code execution, the global interrupt must be disabled. If the global interrupt is enabled, execution will switch to the interrupt service routine. Please see Section 9.1.5 "Interrupts" for more information.
(c) 2007 Microchip Technology Inc.
DS41262D-page 109
PIC16F631/677/685/687/689/690
9.1.6 RESULT FORMATTING
The 10-bit A/D conversion result can be supplied in two formats, left justified or right justified. The ADFM bit of the ADCON0 register controls the output format. Figure 9-3 shows the two output formats.
FIGURE 9-3:
10-BIT A/D CONVERSION RESULT FORMAT
ADRESH ADRESL LSB bit 0 10-bit A/D Result bit 7 bit 0 Unimplemented: Read as `0' LSB bit 0 bit 7 10-bit A/D Result bit 0
(ADFM = 0)
MSB bit 7
(ADFM = 1) bit 7 Unimplemented: Read as `0'
MSB
DS41262D-page 110
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
9.2
9.2.1
ADC Operation
STARTING A CONVERSION
9.2.5
SPECIAL EVENT TRIGGER
To enable the ADC module, the ADON bit of the ADCON0 register must be set to a `1'. Setting the GO/ DONE bit of the ADCON0 register to a `1' will start the Analog-to-Digital conversion. Note: The GO/DONE bit should not be set in the same instruction that turns on the ADC. Refer to Section 9.2.6 "A/D Conversion Procedure".
An ECCP Special Event Trigger allows periodic ADC measurements without software intervention. When this trigger occurs, the GO/DONE bit is set by hardware and the Timer1 counter resets to zero. Using the Special Event Trigger does not assure proper ADC timing. It is the user's responsibility to ensure that the ADC timing requirements are met. See Section 11.0 "Enhanced Capture/Compare/ PWM Module" for more information.
9.2.6 9.2.2 COMPLETION OF A CONVERSION
When the conversion is complete, the ADC module will: * Clear the GO/DONE bit * Set the ADIF flag bit * Update the ADRESH:ADRESL registers with new conversion result
A/D CONVERSION PROCEDURE
This is an example procedure for using the ADC to perform an Analog-to-Digital conversion: 1. Configure Port: * Disable pin output driver (See TRIS register) * Configure pin as analog Configure the ADC module: * Select ADC conversion clock * Configure voltage reference * Select ADC input channel * Select result format * Turn on ADC module Configure ADC interrupt (optional): * Clear ADC interrupt flag * Enable ADC interrupt * Enable peripheral interrupt * Enable global interrupt(1) Wait the required acquisition time(2). Start conversion by setting the GO/DONE bit. Wait for ADC conversion to complete by one of the following: * Polling the GO/DONE bit * Waiting for the ADC interrupt (interrupts enabled) Read ADC Result Clear the ADC interrupt flag (required if interrupt is enabled).
2.
9.2.3
TERMINATING A CONVERSION
If a conversion must be terminated before completion, the GO/DONE bit can be cleared in software. The ADRESH:ADRESL registers will not be updated with the partially complete Analog-to-Digital conversion sample. Instead, the ADRESH:ADRESL register pair will retain the value of the previous conversion. Additionally, a 2 TAD delay is required before another acquisition can be initiated. Following this delay, an input acquisition is automatically started on the selected channel. Note: A device Reset forces all registers to their Reset state. Thus, the ADC module is turned off and any pending conversion is terminated.
3.
4. 5. 6.
9.2.4
ADC OPERATION DURING SLEEP
7. 8.
The ADC module can operate during Sleep. This requires the ADC clock source to be set to the FRC option. When the FRC clock source is selected, the ADC waits one additional instruction before starting the conversion. This allows the SLEEP instruction to be executed, which can reduce system noise during the conversion. If the ADC interrupt is enabled, the device will wake-up from Sleep when the conversion completes. If the ADC interrupt is disabled, the ADC module is turned off after the conversion completes, although the ADON bit remains set. When the ADC clock source is something other than FRC, a SLEEP instruction causes the present conversion to be aborted and the ADC module is turned off, although the ADON bit remains set.
Note 1: The global interrupt can be disabled if the user is attempting to wake-up from Sleep and resume in-line code execution. 2: See Section 9.3 Requirements". "A/D Acquisition
(c) 2007 Microchip Technology Inc.
DS41262D-page 111
PIC16F631/677/685/687/689/690
EXAMPLE 9-1: A/D CONVERSION
;This code block configures the ADC ;for polling, Vdd reference, Frc clock ;and AN0 input. ; ;Conversion start & polling for completion ; are included. ; BANKSEL ADCON1 ; MOVLW B'01110000' ;ADC Frc clock MOVWF ADCON1 ; BANKSEL TRISA ; BSF TRISA,0 ;Set RA0 to input BANKSEL ANSEL ; BSF ANSEL,0 ;Set RA0 to analog BANKSEL ADCON0 ; MOVLW B'10000001' ;Right justify, MOVWF ADCON0 ; Vdd Vref, AN0, On CALL SampleTime ;Acquisiton delay BSF ADCON0,GO ;Start conversion BTFSC ADCON0,GO ;Is conversion done? GOTO $-1 ;No, test again BANKSEL ADRESH ; MOVF ADRESH,W ;Read upper 2 bits MOVWF RESULTHI ;store in GPR space BANKSEL ADRESL ; MOVF ADRESL,W ;Read lower 8 bits MOVWF RESULTLO ;Store in GPR space
9.2.7
ADC REGISTER DEFINITIONS
The following registers are used to control the operation of the ADC.
DS41262D-page 112
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 9-1:
R/W-0 ADFM bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ADCON0: A/D CONTROL REGISTER 0
R/W-0 VCFG 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
ADFM: A/D Conversion Result Format Select bit 1 = Right justified 0 = Left justified VCFG: Voltage Reference bit 1 = VREF pin 0 = VDD CHS<3:0>: Analog Channel Select bits 0000 = AN0 0001 = AN1 0010 = AN2 0011 = AN3 0100 = AN4 0101 = AN5 0110 = AN6 0111 = AN7 1000 = AN8 1001 = AN9 1010 = AN10 1011 = AN11 1100 = CVREF 1101 = 0.6V Reference 1110 = Reserved. Do not use. 1111 = Reserved. Do not use. GO/DONE: A/D Conversion Status bit 1 = A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle. This bit is automatically cleared by hardware when the A/D conversion has completed. 0 = A/D conversion completed/not in progress ADON: ADC Enable bit 1 = ADC is enabled 0 = ADC is disabled and consumes no operating current
bit 6
bit 5-2
bit 1
bit 0
(c) 2007 Microchip Technology Inc.
DS41262D-page 113
PIC16F631/677/685/687/689/690
REGISTER 9-2:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7 bit 6-4 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ADCON1: A/D CONTROL REGISTER 1
R/W-0 ADCS2 R/W-0 ADCS1 R/W-0 ADCS0 U-0 -- U-0 -- U-0 -- U-0 -- bit 0
Unimplemented: Read as `0' ADCS<2:0>: A/D Conversion Clock Select bits 000 = FOSC/2 001 = FOSC/8 010 = FOSC/32 x11 = FRC (clock derived from a dedicated internal oscillator = 500 kHz max) 100 = FOSC/4 101 = FOSC/16 110 = FOSC/64 Unimplemented: Read as `0'
bit 3-0
DS41262D-page 114
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 9-3:
R/W-x ADRES9 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 0
R/W-x ADRES8 R/W-x ADRES7 R/W-x ADRES6 R/W-x ADRES5 R/W-x ADRES4 R/W-x ADRES3 R/W-x ADRES2 bit 0
ADRES<9:2>: ADC Result Register bits Upper 8 bits of 10-bit conversion result
REGISTER 9-4:
R/W-x ADRES1 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5-0
ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 0
R/W-x ADRES0 R/W-x -- R/W-x -- R/W-x -- R/W-x -- R/W-x -- R/W-x -- bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ADRES<1:0>: ADC Result Register bits Lower 2 bits of 10-bit conversion result Reserved: Do not use.
REGISTER 9-5:
R/W-x -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-2 bit 1-0
ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 1
R/W-x -- R/W-x -- R/W-x -- R/W-x -- R/W-x -- R/W-x ADRES9 R/W-x ADRES8 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Reserved: Do not use. ADRES<9:8>: ADC Result Register bits Upper 2 bits of 10-bit conversion result
REGISTER 9-6:
R/W-x ADRES7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0
ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 1
R/W-x ADRES6 R/W-x ADRES5 R/W-x ADRES4 R/W-x ADRES3 R/W-x ADRES2 R/W-x ADRES1 R/W-x ADRES0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ADRES<7:0>: ADC Result Register bits Lower 8 bits of 10-bit conversion result
(c) 2007 Microchip Technology Inc.
DS41262D-page 115
PIC16F631/677/685/687/689/690
9.3 A/D Acquisition Requirements
For the ADC 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 9-4. 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), see Figure 9-4. The maximum recommended impedance for analog sources is 10 k. As the source impedance is decreased, the acquisition time may be decreased. After the analog input channel is selected (or changed), an A/D acquisition must be done before the conversion can be started. To calculate the minimum acquisition time, Equation 9-1 may be used. This equation assumes that 1/2 LSb error is used (1024 steps for the ADC). The 1/2 LSb error is the maximum error allowed for the ADC to meet its specified resolution.
EQUATION 9-1: Assumptions:
ACQUISITION TIME EXAMPLE Temperature = 50C and external impedance of 10k 5.0V VDD
TACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient = TAMP + TC + TCOFF = 5s + TC + [ ( Temperature - 25C ) ( 0.05s/C ) ] The value for TC can be approximated with the following equations:
1VAPPLIED 1 - ----------- = VCHOLD 2047
--------- RC VAPPLIED 1 - e = VCHOLD -------- 1RC VAPPLIED 1 - e = VAPPLIED 1 - ----------- 2047 - Tc - TC
;[1] VCHOLD charged to within 1/2 lsb
;[2] VCHOLD charge response to VAPPLIED
;combining [1] and [2]
Solving for TC:
TC = - CHOLD ( RIC + RSS + RS ) ln(1/2047) = - 10pF ( 1k + 7k + 10k ) ln(0.0004885) = 1.37 s
Therefore: TACQ = 5S + 1.37S + [ ( 50C- 25C ) ( 0.05S/C ) ] = 7.67S
Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out. 2: The charge holding capacitor (CHOLD) is not discharged after each conversion. 3: The maximum recommended impedance for analog sources is 10 k. This is required to meet the pin leakage specification.
DS41262D-page 116
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 9-4: ANALOG INPUT MODEL
VDD Rs VA ANx CPIN 5 pF VT = 0.6V RIC 1k I LEAKAGE 500 nA Sampling Switch SS Rss
VT = 0.6V
CHOLD = 10 pF VSS/VREF-
Legend: CPIN = Input Capacitance = Threshold Voltage VT I LEAKAGE = Leakage current at the pin due to various junctions RIC = Interconnect Resistance SS = Sampling Switch CHOLD = Sample/Hold Capacitance
6V 5V VDD 4V 3V 2V
RSS
5 6 7 8 9 10 11 Sampling Switch (k)
FIGURE 9-5:
ADC TRANSFER FUNCTION
Full-Scale Range
3FFh 3FEh 3FDh ADC Output Code 3FCh 3FBh Full-Scale Transition 1 LSB ideal
004h 003h 002h 001h 000h 1 LSB ideal
Analog Input Voltage
VSS/VREF-
Zero-Scale Transition
VDD/VREF+
(c) 2007 Microchip Technology Inc.
DS41262D-page 117
PIC16F631/677/685/687/689/690
TABLE 9-2:
Name ADCON0 ADCON1 ANSEL ANSELH ADRESH ADRESL INTCON PIE1 PIR1 PORTA PORTB PORTC TRISA TRISB TRISC Legend: Bit 7 ADFM -- ANS7 --
SUMMARY OF ASSOCIATED ADC REGISTERS
Bit 6 VCFG ADCS2 ANS6 -- Bit 5 CHS3 ADCS1 ANS5 -- Bit 4 CHS2 ADCS0 ANS4 -- Bit 3 CHS1 -- ANS3 ANS11 Bit 2 CHS0 -- ANS2 ANS10 Bit 1 GO/DONE -- ANS1 ANS9 Bit 0 ADON -- ANS0 ANS8 Value on POR, BOR 0000 0000 -000 ---1111 1111 ---- 1111 xxxx xxxx xxxx xxxx INTE TXIE TXIF RA4 RB4 RC4 TRISA4 TRISB4 TRISC4 RABIE SSPIE SSPIF RA3 -- RC3 TRISA3 -- TRISC3 T0IF CCP1IE CCP1IF RA2 -- RC2 TRISA2 -- TRISC2 INTF TMR2IE TMR2IF RA1 -- RC1 TRISA1 -- TRISC1 RABIF TMR1IE TMR1IF RA0 -- RC0 TRISA0 -- TRISC0 0000 000x -000 0000 -000 0000 --xx xxxx xxxx ---xxxx xxxx --11 1111 1111 ---1111 1111 Value on all other Resets 0000 0000 -000 ---1111 1111 ---- 1111 uuuu uuuu uuuu uuuu 0000 000x -000 0000 -000 0000 --uu uuuu uuuu ---uuuu uuuu --11 1111 1111 ---1111 1111
A/D Result Register High Byte A/D Result Register Low Byte GIE -- -- -- RB7 RC7 -- TRISB7 TRISC7 PEIE ADIE ADIF -- RB6 RC6 -- TRISB6 TRISC6 T0IE RCIE RCIF RA5 RB5 RC5 TRISA5 TRISB5 TRISC5
x = unknown, u = unchanged, -- = unimplemented read as `0'. Shaded cells are not used for ADC module.
DS41262D-page 118
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
10.0 DATA EEPROM AND FLASH PROGRAM MEMORY CONTROL
10.1 EEADR and EEADRH Registers
The EEADR and EEADRH registers can address up to a maximum of 256 bytes of data EEPROM or up to a maximum of 4K words of program EEPROM. When selecting a program address value, the MSB of the address is written to the EEADRH register and the LSB is written to the EEADR register. When selecting a data address value, only the LSB of the address is written to the EEADR register.
Data EEPROM memory is readable and writable and the Flash program memory (PIC16F685/PIC16F689/ PIC16F690 only) is readable during normal operation (full VDD range). These memories are not directly mapped in the register file space. Instead, they are indirectly addressed through the Special Function Registers (SFRs). There are six SFRs used to access these memories: * * * * * * EECON1 EECON2 EEDAT EEDATH (PIC16F685/PIC16F689/PIC16F690 only) EEADR EEADRH (PIC16F685/PIC16F689/PIC16F690 only)
10.1.1
EECON1 AND EECON2 REGISTERS
EECON1 is the control register for EE memory accesses. Control bit EEPGD (PIC16F685/PIC16F689/PIC16F690) determines if the access will be a program or data memory access. When clear, as it is when reset, any subsequent operations will operate on the data memory. When set, any subsequent operations will operate on the program memory. Program memory can only be read. Control bits RD and WR initiate read and write, respectively. These bits cannot be cleared, only set, in software. They are cleared in hardware at completion of the read or write operation. The inability to clear the WR bit in software prevents the accidental, premature termination of a write operation. The WREN bit, when set, will allow a write operation to data EEPROM. On power-up, the WREN bit is clear. The WRERR bit is set when a write operation is interrupted by a MCLR or a WDT Time-out Reset during normal operation. In these situations, following Reset, the user can check the WRERR bit and rewrite the location. Interrupt flag bit EEIF of the PIR2 register is set when write is complete. It must be cleared in the software. EECON2 is not a physical register. Reading EECON2 will read all `0's. The EECON2 register is used exclusively in the data EEPROM write sequence.
When interfacing the data memory block, EEDAT holds the 8-bit data for read/write, and EEADR holds the address of the EEDAT location being accessed. These devices, except for the PIC16F631, have 256 bytes of data EEPROM with an address range from 0h to 0FFh. The PIC16F631 has 128 bytes of data EEPROM with an address range from 0h to 07Fh. When accessing the program memory block of the PIC16F685/PIC16F689/PIC16F690 devices, the EEDAT and EEDATH registers form a 2-byte word that holds the 14-bit data for read/write, and the EEADR and EEADRH registers form a 2-byte word that holds the 12-bit address of the EEPROM location being read. These devices (PIC16F685/PIC16F689/PIC16F690) have 4K words of program EEPROM with an address range from 0h to 0FFFh. The program memory allows one-word reads. The EEPROM data memory allows byte read and write. 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/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. When the device is code-protected, the CPU may continue to read and write the data EEPROM memory and read the program memory. When code-protected, the device programmer can no longer access data or program memory.
(c) 2007 Microchip Technology Inc.
DS41262D-page 119
PIC16F631/677/685/687/689/690
REGISTER 10-1:
R/W-0 EEDAT7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
EEDAT: EEPROM DATA REGISTER
R/W-0 R/W-0 EEDAT5 R/W-0 EEDAT4 R/W-0 EEDAT3 R/W-0 EEDAT2 R/W-0 EEDAT1 R/W-0 EEDAT0 bit 0
EEDAT6
EEDAT<7:0>: 8 Least Significant Address bits to Write to or Read from data EEPROM or Read from program memory
REGISTER 10-2:
R/W-0 EEADR7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-0 Note 1:
(1)
EEADR: EEPROM ADDRESS REGISTER
R/W-0 R/W-0 EEADR5 R/W-0 EEADR4 R/W-0 EEADR3 R/W-0 EEADR2 R/W-0 EEADR1 R/W-0 EEADR0 bit 0
EEADR6
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
EEADR<7:0>: 8 Least Significant Address bits for EEPROM Read/Write Operation(1) or Read from program memory PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only.
REGISTER 10-3:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6 bit 5-0 Note 1:
EEDATH: EEPROM DATA HIGH BYTE REGISTER(1)
U-0 -- R/W-0 EEDATH5 R/W-0 EEDATH4 R/W-0 EEDATH3 R/W-0 EEDATH2 R/W-0 EEDATH1 R/W-0 EEDATH0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' EEDATH<5:0>: 6 Most Significant Data bits from program memory PIC16F685/PIC16F689/PIC16F690 only.
REGISTER 10-4:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-4 bit 3-0 Note 1:
EEADRH: EEPROM ADDRESS HIGH BYTE REGISTER(1)
U-0 -- U-0 -- U-0 -- R/W-0 EEADRH3 R/W-0 EEADRH2 R/W-0 EEADRH1 R/W-0 EEADRH0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' EEADRH<3:0>: Specifies the 4 Most Significant Address bits or high bits for program memory reads PIC16F685/PIC16F689/PIC16F690 only.
DS41262D-page 120
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 10-5:
R/W-x EEPGD(1) bit 7 Legend: S = Bit can only be set R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
EECON1: EEPROM CONTROL REGISTER
U-0 -- U-0 -- U-0 -- R/W-x WRERR R/W-0 WREN R/S-0 WR R/S-0 RD bit 0
EEPGD: Program/Data EEPROM Select bit(1) 1 = Accesses program memory 0 = Accesses data memory Unimplemented: Read as `0' WRERR: EEPROM Error Flag bit 1 = A write operation is prematurely terminated (any MCLR Reset, any WDT Reset during normal operation or BOR Reset) 0 = The write operation completed WREN: EEPROM Write Enable bit 1 = Allows write cycles 0 = Inhibits write to the data EEPROM WR: Write Control bit EEPGD = 1: This bit is ignored EEPGD = 0: 1 = Initiates a write cycle (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 data EEPROM is complete RD: Read Control bit 1 = Initiates a memory read (the RD is cleared in hardware and can only be set, not cleared, in software.) 0 = Does not initiate a memory read PIC16F685/PIC16F689/PIC16F690 only.
bit 6-4 bit 3
bit 2
bit 1
bit 0
Note 1:
(c) 2007 Microchip Technology Inc.
DS41262D-page 121
PIC16F631/677/685/687/689/690
10.1.2 READING THE DATA EEPROM MEMORY 10.1.3 WRITING TO THE DATA EEPROM MEMORY
To read a data memory location, the user must write the address to the EEADR register, clear the EEPGD control bit of the EECON1 register, and then set control bit RD. The data is available at the very next cycle, in the EEDAT register; therefore, it can be read in the next instruction. EEDAT will hold this value until another read or until it is written to by the user (during a write operation). To write an EEPROM data location, the user must first write the address to the EEADR register and the data to the EEDAT register. Then the user must follow a specific sequence to initiate the write for each byte. The write will not initiate if the above sequence is not followed exactly (write 55h to EECON2, write AAh to EECON2, then set WR bit) for each byte. Interrupts should be disabled during this code segment. Additionally, the WREN bit in EECON1 must be set to enable write. This mechanism prevents accidental writes to data EEPROM due to errant (unexpected) code execution (i.e., lost programs). The user should keep the WREN bit clear at all times, except when updating EEPROM. The WREN bit is not cleared by hardware. After a write sequence has been initiated, clearing the WREN bit will not affect this write cycle. The WR bit will be inhibited from being set unless the WREN bit is set. At the completion of the write cycle, the WR bit is cleared in hardware and the EE Write Complete Interrupt Flag bit (EEIF) is set. The user can either enable this interrupt or poll this bit. EEIF must be cleared by software.
EXAMPLE 10-1:
DATA EEPROM READ
BANKSEL EEADR ; MOVF DATA_EE_ADDR, W; MOVWF EEADR ;Data Memory ;Address to read BANKSEL EECON1 ; BCF EECON1, EEPGD ;Point to DATA memory BSF EECON1, RD ;EE Read BANKSEL EEDAT ; MOVF EEDAT, W ;W = EEDAT BCF STATUS, RP1 ;Bank 0
EXAMPLE 10-2:
BANKSEL MOVF MOVWF MOVF MOVWF BANKSEL BCF BSF BCF BTFSC GOTO MOVLW MOVWF MOVLW MOVWF BSF BSF
DATA EEPROM WRITE
EEADR ; DATA_EE_ADDR, W; EEADR ;Data Memory Address to write DATA_EE_DATA, W; EEDAT ;Data Memory Value to write EECON1 ; EECON1, EEPGD ;Point to DATA memory EECON1, WREN ;Enable writes INTCON, INTCON, $-2 55h EECON2 AAh EECON2 EECON1, INTCON, GIE GIE ;Disable INTs. ;SEE AN576 ; ;Write 55h ; ;Write AAh ;Set WR bit to begin write ;Enable INTs. ;Wait for interrupt to signal write complete (optional) ;Disable writes ;Bank 0
Required Sequence
WR GIE
SLEEP BCF EECON1, WREN BANKSEL 0x00
DS41262D-page 122
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
10.1.4 READING THE FLASH PROGRAM MEMORY (PIC16F685/PIC16F689/ PIC16F690)
EEDAT and EEDATH registers will hold this value until another read or until it is written to by the user. Note 1: The two instructions following a program memory read are required to be NOPs. This prevents the user from executing a two-cycle instruction on the next instruction after the RD bit is set. 2: If the WR bit is set when EEPGD = 1, it will be immediately reset to `0' and no operation will take place.
To read a program memory location, the user must write the Least and Most Significant address bits to the EEADR and EEADRH registers, set the EEPGD control bit of the EECON1 register, and then set control bit RD. Once the read control bit is set, the program memory Flash controller will use the second instruction cycle to read the data. This causes the second instruction immediately following the "BSF EECON1,RD" instruction to be ignored. The data is available in the very next cycle, in the EEDAT and EEDATH registers; therefore, it can be read as two bytes in the following instructions.
EXAMPLE 10-3:
BANKSEL MOVF MOVWF MOVF MOVWF BANKSEL BSF BSF NOP NOP ; BANKSEL MOVF MOVWF MOVF MOVWF BANKSEL
FLASH PROGRAM READ
; ; ;MS Byte of Program Address to read ; ;LS Byte of Program Address to read ; ;Point to PROGRAM memory ;EE Read ;First instruction after BSF EECON1,RD executes normally ;Any instructions here are ignored as program ;memory is read in second cycle after BSF EECON1,RD
Required Sequence
EEADR MS_PROG_EE_ADDR, W EEADRH LS_PROG_EE_ADDR, W EEADR EECON1 EECON1, EEPGD EECON1, RD
;
EEDAT EEDAT, W LOWPMBYTE EEDATH, W HIGHPMBYTE 0x00
; ;W = LS Byte of Program Memory ; ;W = MS Byte of Program EEDAT ; ;Bank 0
(c) 2007 Microchip Technology Inc.
DS41262D-page 123
PIC16F631/677/685/687/689/690
FIGURE 10-1: FLASH PROGRAM MEMORY READ CYCLE EXECUTION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Flash ADDR
PC
PC + 1
EEADRH,EEADR
PC + 3 PC+3
PC + 4
PC + 5
Flash Data
INSTR (PC)
INSTR (PC + 1)
EEDATH,EEDAT
INSTR (PC + 3)
INSTR (PC + 4)
INSTR(PC - 1) executed here
BSF EECON1,RD executed here
INSTR(PC + 1) executed here
Forced NOP executed here
INSTR(PC + 3) executed here
INSTR(PC + 4) executed here
RD bit
EEDATH EEDAT Register
EERHLT
DS41262D-page 124
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
10.2 Write Verify
Depending on the application, good programming practice may dictate that the value written to the data EEPROM should be verified (see Example 10-4) to the desired value to be written. When the data memory is code-protected, only the CPU is able to read and write data to the data EEPROM. It is recommended to code-protect the program memory when code-protecting data memory. This prevents anyone from programming zeroes over the existing code (which will execute as NOPs) to reach an added routine, programmed in unused program memory, which outputs the contents of data memory. Programming unused locations in program memory to `0' will also help prevent data memory code protection from becoming breached.
EXAMPLE 10-4:
BANKSEL EEDAT MOVF EEDAT, W
WRITE VERIFY
; ;EEDAT not changed ;from previous write ; ;YES, Read the ;value written ; ; ;Is data the same ;No, handle error ;Yes, continue ;Bank 0
BANKSEL EECON1 BSF EECON1, RD BANKSEL XORWF BTFSS GOTO : BANKSEL EEDAT EEDAT, W STATUS, Z WRITE_ERR 0x00
10.2.1
USING THE DATA EEPROM
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). When variables in one section change frequently, while variables in another section do not change, it is possible to exceed the total number of write cycles to the EEPROM (specification D124) without exceeding the total number of write cycles to a single byte (specifications D120 and D120A). If this is the case, then a refresh of the array must be performed. For this reason, variables that change infrequently (such as constants, IDs, calibration, etc.) should be stored in Flash program memory.
10.3
Protection Against Spurious Write
There are conditions when the user 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, WREN is cleared. Also, the Power-up Timer (64 ms duration) prevents EEPROM write. The write initiate sequence and the WREN bit together help prevent an accidental write during: * Brown-out * Power Glitch * Software Malfunction
10.4
Data EEPROM Operation During Code-Protect
Data memory can be code-protected by programming the CPD bit in the Configuration Word register (Register 14-1) to `0'.
(c) 2007 Microchip Technology Inc.
DS41262D-page 125
PIC16F631/677/685/687/689/690
TABLE 10-1:
Name EECON1 EECON2 EEADR EEADRH(1) EEDAT EEDATH(1) INTCON PIE2 PIR2 Legend: Note 1: 2:
SUMMARY OF REGISTERS ASSOCIATED WITH DATA EEPROM
Bit 6 -- Bit 5 -- Bit 4 -- Bit 3 WRERR Bit 2 WREN Bit 1 WR Bit 0 RD Value on POR, BOR x--- x000 ---- ---EEADR2 EEADRH2 EEDAT2 EEDATH2 T0IF -- -- EEADR1 EEADRH1 EEDAT1 EEDATH1 INTF -- -- EEADR0 EEADRH0 EEDAT0 EEDATH0 RABIF -- -- 0000 0000 ---- 0000 0000 0000 --00 0000 0000 0000 0000 ---0000 ---Value on all other Resets 0--- q000 ---- ---0000 0000 ---- 0000 0000 0000 --00 0000 0000 0000 0000 ---0000 ----
Bit 7 EEPGD(1)
EEPROM Control Register 2 (not a physical register) EEADR7(2) EEADR6 -- EEDAT7 -- GIE OSFIE OSFIF -- EEDAT6 -- PEIE C2IE C2IF EEADR5 -- EEDAT5 EEDATH5 T0IE C1IE C1IF EEADR4 -- EEDAT4 EEDATH4 INTE EEIE EEIF EEADR3 EEADRH3 EEDAT3 EEDATH3 RABIE -- --
x = unknown, u = unchanged, -- = unimplemented read as `0', q = value depends upon condition. Shaded cells are not used by data EEPROM module. PIC16F685/PIC16F689/PIC16F690 only. PIC16F677/PIC16F685/PIC16F687/PIC16F689/PIC16F690 only.
DS41262D-page 126
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.0 ENHANCED CAPTURE/COMPARE/PWM MODULE
Table 11-1 shows the timer resources required by the ECCP module.
TABLE 11-1:
The Enhanced Capture/Compare/PWM module is a peripheral which allows the user to time and control different events. In Capture mode, the peripheral allows the timing of the duration of an event. The Compare mode allows the user to trigger an external event when a predetermined amount of time has expired. The PWM mode can generate a Pulse-Width Modulated signal of varying frequency and duty cycle.
ECCP MODE - TIMER RESOURCES REQUIRED
Timer Resource Timer1 Timer1 Timer2
ECCP Mode Capture Compare PWM
REGISTER 11-1:
R/W-0 P1M1 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-6
CCP1CON: ENHANCED CCP1 CONTROL REGISTER
R/W-0 P1M0 R/W-0 DC1B1 R/W-0 DC1B0 R/W-0 CCP1M3 R/W-0 CCP1M2 R/W-0 CCP1M1 R/W-0 CCP1M0 bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
P1M<1:0>: PWM Output Configuration bits If CCP1M<3:2> = 00, 01, 10: xx = P1A assigned as Capture/Compare input; P1B, P1C, P1D assigned as port pins If CCP1M<3:2> = 11: 00 = Single output; P1A modulated; P1B, P1C, P1D assigned as port pins 01 = Full-Bridge output forward; P1D modulated; P1A active; P1B, P1C inactive 10 = Half-Bridge output; P1A, P1B modulated with dead-band control; P1C, P1D assigned as port pins 11 = Full-Bridge output reverse; P1B modulated; P1C active; P1A, P1D inactive DC1B<1:0>: PWM Duty Cycle Least Significant bits Capture mode: Unused. Compare mode: Unused. PWM mode: These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L. CCP1M<3:0>: ECCP Mode Select bits 0000 = Capture/Compare/PWM off (resets ECCP module) 0001 = Unused (reserved) 0010 = Compare mode, toggle output on match (CCP1IF bit is set) 0011 = Unused (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, set output on match (CCP1IF bit is set) 1001 = Compare mode, clear output on match (CCP1IF bit is set) 1010 = Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin is unaffected) 1011 = Compare mode, trigger special event (CCP1IF bit is set; CCP1 resets TMR1 or TMR2, and starts an A/D conversion, if the ADC module is enabled) 1100 = PWM mode; P1A, P1C active-high; P1B, P1D active-high 1101 = PWM mode; P1A, P1C active-high; P1B, P1D active-low 1110 = PWM mode; P1A, P1C active-low; P1B, P1D active-high 1111 = PWM mode; P1A, P1C active-low; P1B, P1D active-low
bit 5-4
bit 3-0
(c) 2007 Microchip Technology Inc.
DS41262D-page 127
PIC16F631/677/685/687/689/690
11.1 Capture Mode
11.1.2 TIMER1 MODE SELECTION
In Capture mode, CCPR1H:CCPR1L captures the 16-bit value of the TMR1 register when an event occurs on pin CCP1. An event is defined as one of the following and is configured by the CCP1M<3:0> bits of the CCP1CON register: * * * * Every falling edge Every rising edge Every 4th rising edge Every 16th rising edge Timer1 must be running in Timer mode or Synchronized Counter mode for the CCP module to use the capture feature. In Asynchronous Counter mode, the capture operation may not work.
11.1.3
SOFTWARE INTERRUPT
When a capture is made, the Interrupt Request Flag bit CCP1IF of the PIR1 register is set. The interrupt flag must be cleared in software. If another capture occurs before the value in the CCPR1H, CCPR1L register pair is read, the old captured value is overwritten by the new captured value (see Figure 11-1).
When the Capture mode is changed, a false capture interrupt may be generated. The user should keep the CCP1IE interrupt enable bit of the PIE1 register clear to avoid false interrupts. Additionally, the user should clear the CCP1IF interrupt flag bit of the PIR1 register following any change in operating mode.
11.1.4
CCP PRESCALER
11.1.1
CCP1 PIN CONFIGURATION
In Capture mode, the CCP1 pin should be configured as an input by setting the associated TRIS control bit. Note: If the CCP1 pin is configured as an output, a write to the port can cause a capture condition.
There are four prescaler settings specified by the CCP1M<3:0> bits of the CCP1CON register. Whenever the CCP module is turned off, or the CCP module is not in Capture mode, the prescaler counter is cleared. Any Reset will clear the prescaler counter. Switching from one capture prescaler to another does not clear the prescaler and may generate a false interrupt. To avoid this unexpected operation, turn the module off by clearing the CCP1CON register before changing the prescaler (see Example 11-1).
FIGURE 11-1:
CAPTURE MODE OPERATION BLOCK DIAGRAM
Set Flag bit CCP1IF (PIR1 register)
EXAMPLE 11-1:
BANKSEL CCP1CON CLRF MOVLW
CHANGING BETWEEN CAPTURE PRESCALERS
Prescaler / 1, 4, 16 CCP1 pin
CCPR1H and Edge Detect Capture Enable TMR1H
CCPR1L
MOVWF
TMR1L
;Set Bank bits to point ;to CCP1CON CCP1CON ;Turn CCP module off NEW_CAPT_PS ;Load the W reg with ; the new prescaler ; move value and CCP ON CCP1CON ;Load CCP1CON with this ; value
CCP1CON<3:0> System Clock (FOSC)
DS41262D-page 128
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.2 Compare Mode
11.2.2 TIMER1 MODE SELECTION
In Compare mode, the 16-bit CCPR1 register value is constantly compared against the TMR1 register pair value. When a match occurs, the CCP module may: * * * * * Toggle the CCP1 output Set the CCP1 output Clear the CCP1 output Generate a Special Event Trigger Generate a Software Interrupt In Compare mode, Timer1 must be running in either Timer mode or Synchronized Counter mode. The compare operation may not work in Asynchronous Counter mode.
11.2.3
SOFTWARE INTERRUPT MODE
The action on the pin is based on the value of the CCP1M<3:0> control bits of the CCP1CON register. All Compare modes can generate an interrupt.
When Generate Software Interrupt mode is chosen (CCP1M<3:0> = 1010), the CCP module does not assert control of the CCP1 pin (see the CCP1CON register).
11.2.4
SPECIAL EVENT TRIGGER
FIGURE 11-2:
COMPARE MODE OPERATION BLOCK DIAGRAM
CCP1CON<3:0> Mode Select Set CCP1IF Interrupt Flag (PIR1) 4 CCPR1H CCPR1L
When Special Event Trigger mode is chosen (CCP1M<3:0> = 1011), the CCP module does the following: * Resets Timer1 * Starts an ADC conversion if ADC is enabled The CCP module does not assert control of the CCP1 pin in this mode (see the CCP1CON register). The Special Event Trigger output of the CCP occurs immediately upon a match between the TMR1H, TMR1L register pair and the CCPR1H, CCPR1L register pair. The TMR1H, TMR1L register pair is not reset until the next rising edge of the Timer1 clock. This allows the CCPR1H, CCPR1L register pair to effectively provide a 16-bit programmable period register for Timer1. Note 1: The Special Event Trigger from the CCP module does not set interrupt flag bit TMR1IF of the PIR1 register. 2: Removing the match condition by changing the contents of the CCPR1H and CCPR1L register pair, between the clock edge that generates the Special Event Trigger and the clock edge that generates the Timer1 Reset, will preclude the Reset from occurring.
CCP1 Pin Q S R TRIS Output Enable
Output Logic
Match
Comparator TMR1H TMR1L
Special Event Trigger Special Event Trigger will: * Clear TMR1H and TMR1L registers. * NOT set interrupt flag bit TMR1IF of the PIR1 register. * Set the GO/DONE bit to start the ADC conversion.
11.2.1
CCP1 PIN CONFIGURATION
The user must configure the CCP1 pin as an output by clearing the associated TRIS bit. Note: Clearing the CCP1CON register will force the CCP1 compare output latch to the default low level. This is not the port I/O data latch.
(c) 2007 Microchip Technology Inc.
DS41262D-page 129
PIC16F631/677/685/687/689/690
11.3 PWM Mode
The PWM mode generates a Pulse-Width Modulated signal on the CCP1 pin. The duty cycle, period and resolution are determined by the following registers: * * * * PR2 T2CON CCPR1L CCP1CON The PWM output (Figure 11-4) has a time base (period) and a time that the output stays high (duty cycle).
FIGURE 11-4:
Period Pulse Width
CCP PWM OUTPUT
TMR2 = PR2 TMR2 = CCPR1L:CCP1CON<5:4>
In Pulse-Width Modulation (PWM) mode, the CCP module produces up to a 10-bit resolution PWM output on the CCP1 pin. Since the CCP1 pin is multiplexed with the PORT data latch, the TRIS for that pin must be cleared to enable the CCP1 pin output driver. Note: Clearing the CCP1CON register will relinquish CCP1 control of the CCP1 pin.
TMR2 = 0
Figure 11-3 shows a simplified block diagram of PWM operation. Figure 11-4 shows a typical waveform of the PWM signal. For a step-by-step procedure on how to set up the CCP module for PWM operation, see Section 11.3.7 "Setup for PWM Operation".
FIGURE 11-3:
SIMPLIFIED PWM BLOCK DIAGRAM
CCP1CON<5:4>
Duty Cycle Registers CCPR1L
CCPR1H(2) (Slave) CCP1 Comparator
(1)
R S
Q
TMR2
TRIS Comparator Clear Timer2, toggle CCP1 pin and latch duty cycle
PR2
Note 1:
2:
The 8-bit timer TMR2 register is concatenated with the 2-bit internal system clock (FOSC), or 2 bits of the prescaler, to create the 10-bit time base. In PWM mode, CCPR1H is a read-only register.
DS41262D-page 130
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.3.1 PWM PERIOD EQUATION 11-2: PULSE WIDTH
The PWM period is specified by the PR2 register of Timer2. The PWM period can be calculated using the formula of Equation 11-1. Pulse Width = ( CCPR1L:CCP1CON<5:4> ) * TOSC * (TMR2 Prescale Value)
EQUATION 11-1:
PWM PERIOD EQUATION 11-3: DUTY CYCLE RATIO
PWM Period = [ ( PR2 ) + 1 ] * 4 * TOSC * (TMR2 Prescale Value) 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 the PWM duty cycle = 0%, the pin will not be set.) * The PWM duty cycle is latched from CCPR1L into CCPR1H. Note: The Timer2 postscaler (see Section 7.1 "Timer2 Operation") is not used in the determination of the PWM frequency.
) Duty Cycle Ratio = ( CCPR1L:CCP1CON<5:4> ---------------------------------------------------------------------4 ( PR2 + 1 ) The CCPR1H register and a 2-bit internal latch are used to double buffer the PWM duty cycle. This double buffering is essential for glitchless PWM operation. The 8-bit timer TMR2 register is concatenated with either the 2-bit internal system clock (FOSC), or 2 bits of the prescaler, to create the 10-bit time base. The system clock is used if the Timer2 prescaler is set to 1:1. When the 10-bit time base matches the CCPR1H and 2-bit latch, then the CCP1 pin is cleared (see Figure 11-3).
11.3.2
PWM DUTY CYCLE
11.3.3
PWM RESOLUTION
The PWM duty cycle is specified by writing a 10-bit value to multiple registers: CCPR1L register and DC1B<1:0> bits of the CCP1CON register. The CCPR1L contains the eight MSbs and the DC1B<1:0> bits of the CCP1CON register contain the two LSbs. CCPR1L and DC1B<1:0> bits of the CCP1CON register can be written to at any time. The duty cycle value is not latched into CCPR1H until after the period completes (i.e., a match between PR2 and TMR2 registers occurs). While using the PWM, the CCPR1H register is read-only. Equation 11-2 is used to calculate the PWM pulse width. Equation 11-3 is used to calculate the PWM duty cycle ratio.
The resolution determines the number of available duty cycles for a given period. For example, a 10-bit resolution will result in 1024 discrete duty cycles, whereas an 8-bit resolution will result in 256 discrete duty cycles. The maximum PWM resolution is 10 bits when PR2 is 255. The resolution is a function of the PR2 register value as shown by Equation 11-4.
EQUATION 11-4:
PWM RESOLUTION
Resolution = log [ 4 ( PR2 + 1 ) ] bits ----------------------------------------log ( 2 )
Note:
If the pulse width value is greater than the period the assigned PWM pin(s) will remain unchanged.
TABLE 11-2:
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
1.22 kHz 16 0xFF 10 4.88 kHz 4 0xFF 10 19.53 kHz 1 0xFF 10 78.12 kHz 1 0x3F 8 156.3 kHz 1 0x1F 7 208.3 kHz 1 0x17 6.6
PWM Frequency Timer Prescale (1, 4, 16) PR2 Value Maximum Resolution (bits)
TABLE 11-3:
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz)
1.22 kHz 16 0x65 8 4.90 kHz 4 0x65 8 19.61 kHz 1 0x65 8 76.92 kHz 1 0x19 6 153.85 kHz 1 0x0C 5 200.0 kHz 1 0x09 5
PWM Frequency Timer Prescale (1, 4, 16) PR2 Value Maximum Resolution (bits)
(c) 2007 Microchip Technology Inc.
DS41262D-page 131
PIC16F631/677/685/687/689/690
11.3.4 OPERATION IN SLEEP MODE
In Sleep mode, the TMR2 register will not increment and the state of the module will not change. If the CCP1 pin is driving a value, it will continue to drive that value. When the device wakes up, TMR2 will continue from its previous state.
11.3.5
CHANGES IN SYSTEM CLOCK FREQUENCY
The PWM frequency is derived from the system clock frequency. Any changes in the system clock frequency will result in changes to the PWM frequency. See Section 3.0 "Oscillator Module (With Fail-Safe Clock Monitor)" for additional details.
11.3.6
EFFECTS OF RESET
Any Reset will force all ports to Input mode and the CCP registers to their Reset states.
11.3.7
SETUP FOR PWM OPERATION
The following steps should be taken when configuring the CCP module for PWM operation: 1. 2. 3. Disable the PWM pin (CCP1) output driver by setting the associated TRIS bit. Set the PWM period by loading the PR2 register. Configure the CCP module for the PWM mode by loading the CCP1CON register with the appropriate values. Set the PWM duty cycle by loading the CCPR1L register and DC1B<1:0> bits of the CCP1CON register. Configure and start Timer2: * Clear the TMR2IF interrupt flag bit of the PIR1 register. * Set the Timer2 prescale value by loading the T2CKPS bits of the T2CON register. * Enable Timer2 by setting the TMR2ON bit of the T2CON register. Enable PWM output after a new PWM cycle has started: * Wait until Timer2 overflows (TMR2IF bit of the PIR1 register is set). * Enable the CCP1 pin output driver by clearing the associated TRIS bit.
4.
5.
6.
DS41262D-page 132
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4 PWM (Enhanced Mode)
The Enhanced PWM Mode can generate a PWM signal on up to four different output pins with up to 10-bits of resolution. It can do this through four different PWM Output modes: * * * * Single PWM Half-Bridge PWM Full-Bridge PWM, Forward mode Full-Bridge PWM, Reverse mode The PWM outputs are multiplexed with I/O pins and are designated P1A, P1B, P1C and P1D. The polarity of the PWM pins is configurable and is selected by setting the CCP1M bits in the CCP1CON register appropriately. Table 11-4 shows the pin assignments for each Enhanced PWM mode. Figure 11-5 shows an example of a simplified block diagram of the Enhanced PWM module. Note: To prevent the generation of an incomplete waveform when the PWM is first enabled, the ECCP module waits until the start of a new PWM period before generating a PWM signal.
To select an Enhanced PWM mode, the P1M bits of the CCP1CON register must be set appropriately.
FIGURE 11-5:
Duty Cycle Registers CCPR1L
EXAMPLE SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODE
DC1B<1:0> P1M<1:0> 2 CCP1M<3:0> 4
CCP1/P1A TRIS CCPR1H (Slave) P1B R Q Output Controller P1C TMR2 (1) S P1D Clear Timer2, toggle PWM pin and latch duty cycle PWM1CON TRIS TRIS TRIS
CCP1/P1A
P1B
Comparator
P1C
Comparator
P1D
PR2
Note
1:
The 8-bit timer TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit time base.
Note 1: The TRIS register value for each PWM output must be configured appropriately. 2: Clearing the CCP1CON register will relinquish ECCP control of all PWM output pins. 3: Any pin not used by an Enhanced PWM mode is available for alternate pin functions
TABLE 11-4:
ECCP Mode Single Half-Bridge
EXAMPLE PIN ASSIGNMENTS FOR VARIOUS PWM ENHANCED MODES
P1M<1:0> 00 10 01 11 CCP1/P1A Yes
(1)
P1B Yes(1) Yes Yes Yes
P1C Yes(1) No Yes Yes
P1D Yes(1) No Yes Yes
Yes Yes Yes
Full-Bridge, Forward Full-Bridge, Reverse Note 1:
Pulse Steering enables outputs in Single mode.
(c) 2007 Microchip Technology Inc.
DS41262D-page 133
PIC16F631/677/685/687/689/690
FIGURE 11-6: EXAMPLE PWM (ENHANCED MODE) OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE)
Signal 0 Pulse Width Period 00 (Single Output) P1A Modulated Delay(1) P1A Modulated 10 (Half-Bridge) P1B Modulated P1A Active (Full-Bridge, Forward) P1B Inactive P1C Inactive P1D Modulated P1A Inactive (Full-Bridge, Reverse) P1B Modulated P1C Active P1D Inactive Relationships: * Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value) * Pulse Width = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 Prescale Value) * Delay = 4 * TOSC * (PWM1CON<6:0>) Note 1: Dead-band delay is programmed using the PWM1CON register (Section 11.4.6 "Programmable Dead-Band Delay mode"). Delay(1) PR2+1
P1M<1:0>
01
11
DS41262D-page 134
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 11-7:
P1M<1:0>
EXAMPLE ENHANCED PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
Signal 0 Pulse Width Period PR2+1
00
(Single Output)
P1A Modulated P1A Modulated Delay(1) Delay(1)
10
(Half-Bridge)
P1B Modulated P1A Active
01
(Full-Bridge, Forward)
P1B Inactive P1C Inactive P1D Modulated P1A Inactive
11
(Full-Bridge, Reverse)
P1B Modulated P1C Active P1D Inactive
Relationships: * Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value) * Pulse Width = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 Prescale Value) * Delay = 4 * TOSC * (PWM1CON<6:0>) Note 1: Dead-band delay is programmed using the PWM1CON register (Section 11.4.6 "Programmable Dead-Band Delay mode").
(c) 2007 Microchip Technology Inc.
DS41262D-page 135
PIC16F631/677/685/687/689/690
11.4.1 HALF-BRIDGE MODE
In Half-Bridge mode, two pins are used as outputs to drive push-pull loads. The PWM output signal is output on the CCP1/P1A pin, while the complementary PWM output signal is output on the P1B pin (see Figure 11-6). This mode can be used for Half-Bridge applications, as shown in Figure 11-9, or for Full-Bridge applications, where four power switches are being modulated with two PWM signals. In Half-Bridge mode, the programmable dead-band delay can be used to prevent shoot-through current in Half-Bridge power devices. The value of the PDC<6:0> bits of the PWM1CON register sets the number of instruction cycles before the output is driven active. If the value is greater than the duty cycle, the corresponding output remains inactive during the entire cycle. See Section 11.4.6 "Programmable Dead-Band Delay mode" for more details of the dead-band delay operations. Since the P1A and P1B outputs are multiplexed with the PORT data latches, the associated TRIS bits must be cleared to configure P1A and P1B as outputs.
FIGURE 11-8:
EXAMPLE OF HALF-BRIDGE PWM OUTPUT
Period
Period Pulse Width P1A(2) td P1B(2)
(1)
td
(1)
(1)
td = Dead-Band Delay Note 1: 2: At this time, the TMR2 register is equal to the PR2 register. Output signals are shown as active-high.
FIGURE 11-9:
EXAMPLE OF HALF-BRIDGE APPLICATIONS
Standard Half-Bridge Circuit ("Push-Pull") FET Driver P1A
+ Load
FET Driver P1B
+ -
Half-Bridge Output Driving a Full-Bridge Circuit V+
FET Driver P1A Load
FET Driver
FET Driver P1B
FET Driver
DS41262D-page 136
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4.2 FULL-BRIDGE MODE
In Full-Bridge mode, all four pins are used as outputs. An example of Full-Bridge application is shown in Figure 11-10. In the Forward mode, pin CCP1/P1A is driven to its active state, pin P1D is modulated, while P1B and P1C will be driven to their inactive state as shown in Figure 11-11. In the Reverse mode, P1C is driven to its active state, pin P1B is modulated, while P1A and P1D will be driven to their inactive state as shown Figure 11-11. P1A, P1B, P1C and P1D outputs are multiplexed with the PORT data latches. The associated TRIS bits must be cleared to configure the P1A, P1B, P1C and P1D pins as outputs.
FIGURE 11-10:
EXAMPLE OF FULL-BRIDGE APPLICATION
V+
FET Driver P1A
QA
QC
FET Driver
P1B FET Driver
Load FET Driver
P1C
QB
QD
VP1D
(c) 2007 Microchip Technology Inc.
DS41262D-page 137
PIC16F631/677/685/687/689/690
FIGURE 11-11:
Forward Mode Period P1A(2) Pulse Width P1B(2)
EXAMPLE OF FULL-BRIDGE PWM OUTPUT
P1C(2)
P1D(2)
(1) (1)
Reverse Mode Period Pulse Width P1A
(2)
P1B(2) P1C(2)
P1D(2)
(1) (1)
Note 1: 2:
At this time, the TMR2 register is equal to the PR2 register. Output signal is shown as active-high.
DS41262D-page 138
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4.2.1 Direction Change in Full-Bridge Mode
In the Full-Bridge mode, the P1M1 bit in the CCP1CON register allows users to control the forward/reverse direction. When the application firmware changes this direction control bit, the module will change to the new direction on the next PWM cycle. A direction change is initiated in software by changing the P1M1 bit of the CCP1CON register. The following sequence occurs four Timer2 cycles prior to the end of the current PWM period: * The modulated outputs (P1B and P1D) are placed in their inactive state. * The associated unmodulated outputs (P1A and P1C) are switched to drive in the opposite direction. * PWM modulation resumes at the beginning of the next period. See Figure 11-12 for an illustration of this sequence. The Full-Bridge mode does not provide dead-band delay. As one output is modulated at a time, dead-band delay is generally not required. There is a situation where dead-band delay is required. This situation occurs when both of the following conditions are true: 1. 2. The direction of the PWM output changes when the duty cycle of the output is at or near 100%. The turn off time of the power switch, including the power device and driver circuit, is greater than the turn on time.
Figure 11-13 shows an example of the PWM direction changing from forward to reverse, at a near 100% duty cycle. In this example, at time t1, the output P1A and P1D become inactive, while output P1C becomes active. Since the turn off time of the power devices is longer than the turn on time, a shoot-through current will flow through power devices QC and QD (see Figure 11-10) for the duration of `t'. The same phenomenon will occur to power devices QA and QB for PWM direction change from reverse to forward. If changing PWM direction at high duty cycle is required for an application, two possible solutions for eliminating the shoot-through current are: 1. 2. Reduce PWM duty cycle for one PWM period before changing directions. Use switch drivers that can drive the switches off faster than they can drive them on.
Other options to prevent shoot-through current may exist.
FIGURE 11-12:
Signal
EXAMPLE OF PWM DIRECTION CHANGE
Period(1) Period
P1A (Active-High) P1B (Active-High) P1C (Active-High)
(2)
Pulse Width
P1D (Active-High) Pulse Width Note 1: 2: The direction bit P1M1 of the CCP1CON register is written any time during the PWM cycle. When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle. The modulated P1B and P1D signals are inactive at this time. The length of this time is four Timer2 counts.
(c) 2007 Microchip Technology Inc.
DS41262D-page 139
PIC16F631/677/685/687/689/690
FIGURE 11-13: EXAMPLE OF PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
Forward Period t1 Reverse Period
P1A P1B P1C
PW
P1D
PW TON
External Switch C TOFF External Switch D Potential Shoot-Through Current T = TOFF - TON
Note 1: 2: 3:
All signals are shown as active-high. TON is the turn on delay of power switch QC and its driver. TOFF is the turn off delay of power switch QD and its driver.
11.4.3
START-UP CONSIDERATIONS
When any PWM mode is used, the application hardware must use the proper external pull-up and/or pull-down resistors on the PWM output pins. Note: When the microcontroller is released from Reset, all of the I/O pins are in the high-impedance state. The external circuits must keep the power switch devices in the OFF state until the microcontroller drives the I/O pins with the proper signal levels or activates the PWM output(s).
The CCP1M<1:0> bits of the CCP1CON register allow the user to choose whether the PWM output signals are active-high or active-low for each pair of PWM output pins (P1A/P1C and P1B/P1D). The PWM output polarities must be selected before the PWM pin output drivers are enabled. Changing the polarity configuration while the PWM pin output drivers are enabled is not recommended since it may result in damage to the application circuits. The P1A, P1B, P1C and P1D output latches may not be in the proper states when the PWM module is initialized. Enabling the PWM pin output drivers at the same time as the Enhanced PWM modes may cause damage to the application circuit. The Enhanced PWM modes must be enabled in the proper Output mode and complete a full PWM cycle before enabling the PWM pin output drivers. The completion of a full PWM cycle is indicated by the TMR2IF bit of the PIR1 register being set as the second PWM period begins.
DS41262D-page 140
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4.4 ENHANCED PWM AUTO-SHUTDOWN MODE
The PWM mode supports an Auto-Shutdown mode that will disable the PWM outputs when an external shutdown event occurs. Auto-Shutdown mode places the PWM output pins into a predetermined state. This mode is used to help prevent the PWM from damaging the application. The auto-shutdown sources are selected using the ECCPASx bits of the ECCPAS register. A shutdown event may be generated by: * * * * A logic `0' on the INT pin Comparator C1 Comparator C2 Setting the ECCPASE bit in firmware A shutdown condition is indicated by the ECCPASE (Auto-Shutdown Event Status) bit of the ECCPAS register. If the bit is a `0', the PWM pins are operating normally. If the bit is a `1', the PWM outputs are in the shutdown state. When a shutdown event occurs, two things happen: The ECCPASE bit is set to `1'. The ECCPASE will remain set until cleared in firmware or an auto-restart occurs (see Section 11.4.5 "Auto-Restart Mode"). The enabled PWM pins are asynchronously placed in their shutdown states. The PWM output pins are grouped into pairs [P1A/P1C] and [P1B/P1D]. The state of each pin pair is determined by the PSSAC and PSSBD bits of the ECCPAS register. Each pin pair may be placed into one of three states: * Drive logic `1' * Drive logic `0' * Tri-state (high-impedance)
REGISTER 11-2:
U-0 ECCPASE bit 7 Legend: R = Readable bit -n = Value at POR bit 7
ECCPAS: ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN CONTROL REGISTER
U-0 R/W-0 ECCPAS1 R/W-0 ECCPAS0 R/W-0 PSSAC1 R/W-0 PSSAC0 R/W-0 PSSBD1 R/W-0 PSSBD0 bit 0
ECCPAS2
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
ECCPASE: ECCP Auto-Shutdown Event Status bit 1 = A shutdown event has occurred; ECCP outputs are in shutdown state 0 = ECCP outputs are operating ECCPAS<2:0>: ECCP Auto-shutdown Source Select bits 000 = Auto-Shutdown is disabled 001 = Comparator C1 output change 010 = Comparator C2 output change(1) 011 = Either Comparator C1 or C2 change 100 = VIL on INT pin 101 = VIL on INT pin or Comparator C1 change 110 = VIL on INT pin or Comparator C2 change 111 = VIL on INT pin or Comparator C1 or C2 change PSSACn: Pins P1A and P1C Shutdown State Control bits 00 = Drive pins P1A and P1C to `0' 01 = Drive pins P1A and P1C to `1' 1x = Pins P1A and P1C tri-state PSSBDn: Pins P1B and P1D Shutdown State Control bits 00 = Drive pins P1B and P1D to `0' 01 = Drive pins P1B and P1D to `1' 1x = Pins P1B and P1D tri-state If C2SYNC is enabled, the shutdown will be delayed by Timer1.
bit 6-4
bit 3-2
bit 1-0
Note 1:
(c) 2007 Microchip Technology Inc.
DS41262D-page 141
PIC16F631/677/685/687/689/690
Note 1: The auto-shutdown condition is a level-based signal, not an edge-based signal. As long as the level is present, the auto-shutdown will persist. 2: Writing to the ECCPASE bit is disabled while an auto-shutdown condition persists. 3: Once the auto-shutdown condition has been removed and the PWM restarted (either through firmware or auto-restart) the PWM signal will always restart at the beginning of the next PWM period.
FIGURE 11-14:
PWM AUTO-SHUTDOWN WITH FIRMWARE RESTART (PRSEN = 0)
PWM Period
Shutdown Event ECCPASE bit PWM Activity Normal PWM Start of PWM Period ECCPASE Cleared by Shutdown Shutdown Firmware PWM Event Occurs Event Clears Resumes
11.4.5
AUTO-RESTART MODE
The Enhanced PWM can be configured to automatically restart the PWM signal once the auto-shutdown condition has been removed. Auto-restart is enabled by setting the PRSEN bit in the PWM1CON register. If auto-restart is enabled, the ECCPASE bit will remain set as long as the auto-shutdown condition is active. When the auto-shutdown condition is removed, the ECCPASE bit will be cleared via hardware and normal operation will resume.
FIGURE 11-15:
PWM AUTO-SHUTDOWN WITH AUTO-RESTART ENABLED (PRSEN = 1)
PWM Period
Shutdown Event ECCPASE bit PWM Activity Normal PWM Start of PWM Period Shutdown Shutdown Event Occurs Event Clears PWM Resumes
DS41262D-page 142
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4.6 PROGRAMMABLE DEAD-BAND DELAY MODE FIGURE 11-16:
In Half-Bridge applications where all power switches are modulated at the PWM frequency, the power switches normally require more time to turn off than to turn on. If both the upper and lower power switches are switched at the same time (one turned on, and the other turned off), both switches may be on for a short period of time until one switch completely turns off. During this brief interval, a very high current (shoot-through current) will flow through both power switches, shorting the bridge supply. To avoid this potentially destructive shoot-through current from flowing during switching, turning on either of the power switches is normally delayed to allow the other switch to completely turn off. In Half-Bridge mode, a digitally programmable dead-band delay is available to avoid shoot-through current from destroying the bridge power switches. The delay occurs at the signal transition from the non-active state to the active state. See Figure 11-8 for illustration. The lower seven bits of the associated PWM1CON register (Register 11-3) sets the delay period in terms of microcontroller instruction cycles (TCY or 4 TOSC).
EXAMPLE OF HALF-BRIDGE PWM OUTPUT
Period
Period Pulse Width P1A(2) td P1B(2)
(1)
td
(1)
(1)
td = Dead-Band Delay Note 1: 2: At this time, the TMR2 register is equal to the PR2 register. Output signals are shown as active-high.
FIGURE 11-17:
EXAMPLE OF HALF-BRIDGE APPLICATIONS
V+
Standard Half-Bridge Circuit ("Push-Pull") FET Driver P1A
+ V Load
FET Driver P1B
+ V -
V-
(c) 2007 Microchip Technology Inc.
DS41262D-page 143
PIC16F631/677/685/687/689/690
REGISTER 11-3:
R/W-0 PRSEN bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
PWM1CON: ENHANCED PWM CONTROL REGISTER
R/W-0 PDC6 R/W-0 PDC5 R/W-0 PDC4 R/W-0 PDC3 R/W-0 PDC2 R/W-0 PDC1 R/W-0 PDC0 bit 0
PRSEN: PWM Restart Enable bit 1 = Upon auto-shutdown, the ECCPASE bit clears automatically once the shutdown event goes away; the PWM restarts automatically 0 = Upon auto-shutdown, ECCPASE must be cleared in software to restart the PWM PDC<6:0>: PWM Delay Count bits PDCn = Number of FOSC/4 (4 * TOSC) cycles between the scheduled time when a PWM signal should transition active and the actual time it transitions active Bit resets to `0' with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe mode is enabled.
bit 6-0
Note 1:
DS41262D-page 144
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4.7 PULSE STEERING MODE
Note: The associated TRIS bits must be set to output (`0') to enable the pin output driver in order to see the PWM signal on the pin. In Single Output mode, pulse steering allows any of the PWM pins to be the modulated signal. Additionally, the same PWM signal can be simultaneously available on multiple pins. Once the Single Output mode is selected (CCP1M<3:2> = 11 and P1M<1:0> = 00 of the CCP1CON register), the user firmware can bring out the same PWM signal to one, two, three or four output pins by setting the appropriate STR bits of the PSTRCON register, as shown in Figure 11-18.
While the PWM Steering mode is active, CCP1M<1:0> bits of the CCP1CON register select the PWM output polarity for the P1 pins. The PWM auto-shutdown operation also applies to PWM Steering mode as described in Section 11.4.4 "Enhanced PWM Auto-shutdown mode". An auto-shutdown event will only affect pins that have PWM outputs enabled.
REGISTER 11-4:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-5 bit 4
PSTRCON: PULSE STEERING CONTROL REGISTER(1)
U-0 -- U-0 -- R/W-0 STRSYNC R/W-0 STRD R/W-0 STRC R/W-0 STRB R/W-1 STRA bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
Unimplemented: Read as `0' STRSYNC: Steering Sync bit 1 = Output steering update occurs on next PWM period 0 = Output steering update occurs at the beginning of the instruction cycle boundary STRD: Steering Enable bit D 1 = P1D pin has the PWM waveform with polarity control from CCP1M<1:0> 0 = P1D pin is assigned to port pin STRC: Steering Enable bit C 1 = P1C pin has the PWM waveform with polarity control from CCP1M<1:0> 0 = P1C pin is assigned to port pin STRB: Steering Enable bit B 1 = P1B pin has the PWM waveform with polarity control from CCP1M<1:0> 0 = P1B pin is assigned to port pin STRA: Steering Enable bit A 1 = P1A pin has the PWM waveform with polarity control from CCP1M<1:0> 0 = P1A pin is assigned to port pin The PWM Steering mode is available only when the CCP1CON register bits CCP1M<3:2> = 11 and P1M<1:0> = 00.
bit 3
bit 2
bit 1
bit 0
Note 1:
(c) 2007 Microchip Technology Inc.
DS41262D-page 145
PIC16F631/677/685/687/689/690
FIGURE 11-18:
STRA P1A Signal CCP1M1 PORT Data STRB CCP1M0 PORT Data STRC CCP1M1 PORT Data STRD CCP1M0 PORT Data 1 0 TRIS Note 1: Port outputs are configured as shown when the CCP1CON register bits P1M<1:0> = 00 and CCP1M<3:2> = 11. Single PWM output requires setting at least one of the STRx bits. 1 0 TRIS 1 0 TRIS P1A pin 1 0
SIMPLIFIED STEERING BLOCK DIAGRAM
TRIS
P1B pin
P1C pin
P1D pin
2:
DS41262D-page 146
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
11.4.7.1 Steering Synchronization
The STRSYNC bit of the PSTRCON register gives the user two selections of when the steering event will happen. When the STRSYNC bit is `0', the steering event will happen at the end of the instruction that writes to the PSTRCON register. In this case, the output signal at the P1 pins may be an incomplete PWM waveform. This operation is useful when the user firmware needs to immediately remove a PWM signal from the pin. When the STRSYNC bit is `1', the effective steering update will happen at the beginning of the next PWM period. In this case, steering on/off the PWM output will always produce a complete PWM waveform. Figures 11-19 and 11-20 illustrate the timing diagrams of the PWM steering depending on the STRSYNC setting.
FIGURE 11-19:
EXAMPLE OF STEERING EVENT AT END OF INSTRUCTION (STRSYNC = 0)
PWM Period
PWM STRn
P1
PORT Data P1n = PWM
PORT Data
FIGURE 11-20:
EXAMPLE OF STEERING EVENT AT BEGINNING OF INSTRUCTION (STRSYNC = 1)
PWM
STRn
P1
PORT Data P1n = PWM
PORT Data
(c) 2007 Microchip Technology Inc.
DS41262D-page 147
PIC16F631/677/685/687/689/690
TABLE 11-5:
Name CCP1CON CM1CON0 CM2CON0 CM2CON1 CCPR1L CCPR1H ECCPAS INTCON PIE1 PIR1 PSTRCON PWM1CON T1CON T2CON TMR1L TMR1H TMR2 TRISC
SUMMARY OF REGISTERS ASSOCIATED WITH CAPTURE, COMPARE AND PWM
Bit 6 P1M0 C1OUT C2OUT Bit 5 DC1B1 C1OE C2OE -- Bit 4 DC1B0 C1POL C2POL -- Bit 3 CCP1M3 -- -- -- Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets
Bit 7 P1M1 C1ON C2ON
CCP1M2 CCP1M1 CCP1M0 0000 0000 0000 0000 C1R C2R -- C1CH1 C2CH1 T1GSS C1CH0 C2CH0 0000 -000 0000 -000 0000 -000 0000 -000 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu
MC1OUT MC2OUT
C2SYNC 00-- --10 00-- --10
Capture/Compare/PWM Register 1 Low Byte Capture/Compare/PWM Register 1 High Byte ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 GIE -- -- -- PRSEN T1GINV -- PEIE ADIE ADIF -- PDC6 T0IE RCIE RCIF -- PDC5 INTE TXIE TXIF STRSYNC PDC4 PSSAC1 RABIE SSPIE SSPIF STRD PDC3 PSSAC0 T0IF CCP1IE CCP1IF STRC PDC2 PSSBD1 INTF TMR2IE TMR2IF STRB PDC1 RABIF TMR1IE TMR1IF STRA PDC0
PSSBD0 0000 0000 0000 0000 0000 0000 0000 0000 -000 0000 -000 0000 -000 0000 -000 0000 ---0 0001 ---0 0001 0000 0000 0000 0000
TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR1CS TMR1ON 0000 0000 uuuu uuuu xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu 0000 0000 0000 0000 TRISC0 1111 1111 1111 1111
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
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 Timer2 Module Register TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1
Legend: - = Unimplemented locations, read as `0', u = unchanged, x = unknown. Shaded cells are not used by the Capture, Compare and PWM.
DS41262D-page 148
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.0 ENHANCED UNIVERSAL SYNCHRONOUS ASYNCHRONOUS RECEIVER TRANSMITTER (EUSART)
The EUSART module includes the following capabilities: * * * * * * * * * * Full-duplex asynchronous transmit and receive Two-character input buffer One-character output buffer Programmable 8-bit or 9-bit character length Address detection in 9-bit mode Input buffer overrun error detection Received character framing error detection Half-duplex synchronous master Half-duplex synchronous slave Programmable clock polarity in synchronous modes
The Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) module is a serial I/O communications peripheral. It contains all the clock generators, shift registers and data buffers necessary to perform an input or output serial data transfer independent of device program execution. The EUSART, also known as a Serial Communications Interface (SCI), can be configured as a full-duplex asynchronous system or half-duplex synchronous system. Full-Duplex mode is useful for communications with peripheral systems, such as CRT terminals and personal computers. Half-Duplex Synchronous mode is intended for communications with peripheral devices, such as A/D or D/A integrated circuits, serial EEPROMs or other microcontrollers. These devices typically do not have internal clocks for baud rate generation and require the external clock signal provided by a master synchronous device.
The EUSART module implements the following additional features, making it ideally suited for use in Local Interconnect Network (LIN) bus systems: * Automatic detection and calibration of the baud rate * Wake-up on Break reception * 13-bit Break character transmit Block diagrams of the EUSART transmitter and receiver are shown in Figure 12-1 and Figure 12-2.
FIGURE 12-1:
EUSART TRANSMIT BLOCK DIAGRAM
Data Bus TXIE Interrupt TXREG Register 8 MSb (8) LSb TX/CK pin Pin Buffer and Control TXIF
***
Transmit Shift Register (TSR)
0
TXEN Baud Rate Generator TRMT FOSC /n n +1 Multiplier SYNC SPBRGH SPBRG BRGH BRG16 x4 x16 x64 0 0 0 TX9D TX9 SPEN
BRG16
1X00 X110 X101
(c) 2007 Microchip Technology Inc.
DS41262D-page 149
PIC16F631/677/685/687/689/690
FIGURE 12-2: EUSART RECEIVE BLOCK DIAGRAM
SPEN CREN OERR RCIDL
RX/DT pin Pin Buffer and Control Baud Rate Generator FOSC Data Recovery
MSb Stop (8) 7
RSR Register
LSb 0 Start
***
RX9
1
/n
BRG16 +1 Multiplier SYNC SPBRGH SPBRG BRGH BRG16 x4 x16 x64 0 0 0 1X00 X110 X101
n
FERR
RX9D
RCREG Register 8 Data Bus RCIF RCIE
FIFO
Interrupt
The operation of the EUSART module is controlled through three registers: * Transmit Status and Control (TXSTA) * Receive Status and Control (RCSTA) * Baud Rate Control (BAUDCTL) These registers are detailed in Register 12-1, Register 12-2 and Register 12-3, respectively.
DS41262D-page 150
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.1 EUSART Asynchronous Mode
Note 1: When the SPEN bit is set, the RX/DT I/O pin is automatically configured as an input, regardless of the state of the corresponding TRIS bit and whether or not the EUSART receiver is enabled. The RX/DT pin data can be read via a normal PORT read but PORT latch data output is precluded. 2: The TXIF transmitter interrupt flag is set when the TXEN enable bit is set. The EUSART transmits and receives data using the standard non-return-to-zero (NRZ) format. NRZ is implemented with two levels: a VOH mark state which represents a `1' data bit, and a VOL space state which represents a `0' data bit. NRZ refers to the fact that consecutively transmitted data bits of the same value stay at the output level of that bit without returning to a neutral level between each bit transmission. An NRZ transmission port idles in the mark state. Each character transmission consists of one Start bit followed by eight or nine data bits and is always terminated by one or more Stop bits. The Start bit is always a space and the Stop bits are always marks. The most common data format is 8 bits. Each transmitted bit persists for a period of 1/(Baud Rate). An on-chip dedicated 8-bit/16-bit Baud Rate Generator is used to derive standard baud rate frequencies from the system oscillator. See Table 12-5 for examples of baud rate configurations. The EUSART transmits and receives the LSb first. The EUSART's transmitter and receiver are functionally independent, but share the same data format and baud rate. Parity is not supported by the hardware, but can be implemented in software and stored as the ninth data bit.
12.1.1.2
Transmitting Data
12.1.1
EUSART ASYNCHRONOUS TRANSMITTER
A transmission is initiated by writing a character to the TXREG register. If this is the first character, or the previous character has been completely flushed from the TSR, the data in the TXREG is immediately transferred to the TSR register. If the TSR still contains all or part of a previous character, the new character data is held in the TXREG until the Stop bit of the previous character has been transmitted. The pending character in the TXREG is then transferred to the TSR in one TCY immediately following the Stop bit transmission. The transmission of the Start bit, data bits and Stop bit sequence commences immediately following the transfer of the data to the TSR from the TXREG.
12.1.1.3
Transmit Interrupt Flag
The EUSART transmitter block diagram is shown in Figure 12-1. The heart of the transmitter is the serial Transmit Shift Register (TSR), which is not directly accessible by software. The TSR obtains its data from the transmit buffer, which is the TXREG register.
12.1.1.1
Enabling the Transmitter
The EUSART transmitter is enabled for asynchronous operations by configuring the following three control bits: * TXEN = 1 * SYNC = 0 * SPEN = 1 All other EUSART control bits are assumed to be in their default state. Setting the TXEN bit of the TXSTA register enables the transmitter circuitry of the EUSART. Clearing the SYNC bit of the TXSTA register configures the EUSART for asynchronous operation. Setting the SPEN bit of the RCSTA register enables the EUSART and automatically configures the TX/CK I/O pin as an output. If the TX/CK pin is shared with an analog peripheral the analog I/O function must be disabled by clearing the corresponding ANSEL bit.
The TXIF interrupt flag bit of the PIR1 register is set whenever the EUSART transmitter is enabled and no character is being held for transmission in the TXREG. In other words, the TXIF bit is only clear when the TSR is busy with a character and a new character has been queued for transmission in the TXREG. The TXIF flag bit is not cleared immediately upon writing TXREG. TXIF becomes valid in the second instruction cycle following the write execution. Polling TXIF immediately following the TXREG write will return invalid results. The TXIF bit is read-only, it cannot be set or cleared by software. The TXIF interrupt can be enabled by setting the TXIE interrupt enable bit of the PIE1 register. However, the TXIF flag bit will be set whenever the TXREG is empty, regardless of the state of TXIE enable bit. To use interrupts when transmitting data, set the TXIE bit only when there is more data to send. Clear the TXIE interrupt enable bit upon writing the last character of the transmission to the TXREG.
(c) 2007 Microchip Technology Inc.
DS41262D-page 151
PIC16F631/677/685/687/689/690
12.1.1.4 TSR Status 12.1.1.6
1.
Asynchronous Transmission Set-up:
The TRMT bit of the TXSTA register indicates the status of the TSR register. This is a read-only bit. The TRMT bit is set when the TSR register is empty and is cleared when a character is transferred to the TSR register from the TXREG. The TRMT bit remains clear until all bits have been shifted out of the TSR register. No interrupt logic is tied to this bit, so the user has to poll this bit to determine the TSR status. Note: The TSR register is not mapped in data memory, so it is not available to the user.
2. 3.
12.1.1.5
Transmitting 9-Bit Characters
4.
The EUSART supports 9-bit character transmissions. When the TX9 bit of the TXSTA register is set the EUSART will shift 9 bits out for each character transmitted. The TX9D bit of the TXSTA register is the ninth, and Most Significant, data bit. When transmitting 9-bit data, the TX9D data bit must be written before writing the 8 Least Significant bits into the TXREG. All nine bits of data will be transferred to the TSR shift register immediately after the TXREG is written. A special 9-bit Address mode is available for use with multiple receivers. See Section 12.1.2.7 "Address Detection" for more information on the Address mode.
5.
6. 7.
Initialize the SPBRGH, SPBRG register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 12.3 "EUSART Baud Rate Generator (BRG)"). Enable the asynchronous serial port by clearing the SYNC bit and setting the SPEN bit. If 9-bit transmission is desired, set the TX9 control bit. A set ninth data bit will indicate that the 8 Least Significant data bits are an address when the receiver is set for address detection. Enable the transmission by setting the TXEN control bit. This will cause the TXIF interrupt bit to be set. If interrupts are desired, set the TXIE interrupt enable bit. An interrupt will occur immediately provided that the GIE and PEIE bits of the INTCON register are also set. If 9-bit transmission is selected, the ninth bit should be loaded into the TX9D data bit. Load 8-bit data into the TXREG register. This will start the transmission.
FIGURE 12-3:
Write to TXREG BRG Output (Shift Clock) RC4/C2OUT/TX/CK 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
1 TCY
TRMT bit (Transmit Shift Reg. Empty Flag)
Word 1 Transmit Shift Reg
FIGURE 12-4:
Write to TXREG BRG Output (Shift Clock) RC4/C2OUT/TX/CK pin TXIF bit (Interrupt Reg. Flag) TRMT bit (Transmit Shift Reg. Empty Flag)
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Word 1 Word 2
Start bit 1 TCY
bit 0
bit 1 Word 1
bit 7/8
Stop bit
Start bit Word 2
bit 0
1 TCY Word 1 Transmit Shift Reg. Word 2 Transmit Shift Reg.
Note:
This timing diagram shows two consecutive transmissions.
DS41262D-page 152
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 12-1:
Name BAUDCTL INTCON PIE1 PIR1 RCREG RCSTA SPBRG SPBRGH TRISB TXREG TXSTA Legend:
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Bit 6 RCIDL PEIE ADIE ADIF RX9 BRG6 BRG14 TRISB6 TX9 Bit 5 -- T0IE RCIE RCIF SREN BRG5 BRG13 TRISB5 TXEN Bit 4 SCKP INTE TXIE TXIF CREN BRG4 BRG12 TRISB4 SYNC SENDB BRGH TRMT TX9D Bit 3 BRG16 RABIE SSPIE SSPIF ADDEN BRG3 BRG11 Bit 2 -- T0IF CCP1IE CCP1IF FERR BRG2 BRG10 Bit 1 WUE INTF TMR2IE TMR2IF OERR BRG1 BRG9 Bit 0 ABDEN RABIF TMR1IE TMR1IF RX9D BRG0 BRG8 Value on POR, BOR 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010
Bit 7 ABDOVF GIE -- -- SPEN BRG7 BRG15 TRISB7 CSRC
EUSART Receive Data Register
EUSART Transmit Data Register
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for Asynchronous Transmission.
(c) 2007 Microchip Technology Inc.
DS41262D-page 153
PIC16F631/677/685/687/689/690
12.1.2 EUSART ASYNCHRONOUS RECEIVER 12.1.2.2 Receiving Data
The Asynchronous mode would typically be used in RS-232 systems. The receiver block diagram is shown in Figure 12-2. The data is received on the RX/DT pin 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 serial Receive Shift Register (RSR) operates at the bit rate. When all 8 or 9 bits of the character have been shifted in, they are immediately transferred to a two character First-In-First-Out (FIFO) memory. The FIFO buffering allows reception of two complete characters and the start of a third character before software must start servicing the EUSART receiver. The FIFO and RSR registers are not directly accessible by software. Access to the received data is via the RCREG register. The receiver data recovery circuit initiates character reception on the falling edge of the first bit. The first bit, also known as the Start bit, is always a zero. The data recovery circuit counts one-half bit time to the center of the Start bit and verifies that the bit is still a zero. If it is not a zero then the data recovery circuit aborts character reception, without generating an error, and resumes looking for the falling edge of the Start bit. If the Start bit zero verification succeeds then the data recovery circuit counts a full bit time to the center of the next bit. The bit is then sampled by a majority detect circuit and the resulting `0' or `1' is shifted into the RSR. This repeats until all data bits have been sampled and shifted into the RSR. One final bit time is measured and the level sampled. This is the Stop bit, which is always a `1'. If the data recovery circuit samples a `0' in the Stop bit position then a framing error is set for this character, otherwise the framing error is cleared for this character. See Section 12.1.2.4 "Receive Framing Error" for more information on framing errors. Immediately after all data bits and the Stop bit have been received, the character in the RSR is transferred to the EUSART receive FIFO and the RCIF interrupt flag bit of the PIR1 register is set. The top character in the FIFO is transferred out of the FIFO by reading the RCREG register. Note: If the receive FIFO is overrun, no additional characters will be received until the overrun condition is cleared. See Section 12.1.2.5 "Receive Overrun Error" for more information on overrun errors.
12.1.2.1
Enabling the Receiver
The EUSART receiver is enabled for asynchronous operation by configuring the following three control bits: * CREN = 1 * SYNC = 0 * SPEN = 1 All other EUSART control bits are assumed to be in their default state. Setting the CREN bit of the RCSTA register enables the receiver circuitry of the EUSART. Clearing the SYNC bit of the TXSTA register configures the EUSART for asynchronous operation. Setting the SPEN bit of the RCSTA register enables the EUSART and automatically configures the RX/DT I/O pin as an input. If the RX/DT pin is shared with an analog peripheral the analog I/O function must be disabled by clearing the corresponding ANSEL bit. Note: When the SPEN bit is set the TX/CK I/O pin is automatically configured as an output, regardless of the state of the corresponding TRIS bit and whether or not the EUSART transmitter is enabled. The PORT latch is disconnected from the output driver so it is not possible to use the TX/CK pin as a general purpose output.
12.1.2.3
Receive Interrupts
The RCIF interrupt flag bit of the PIR1 register is set whenever the EUSART receiver is enabled and there is an unread character in the receive FIFO. The RCIF interrupt flag bit is read-only, it cannot be set or cleared by software. RCIF interrupts are enabled by setting the following bits: * RCIE interrupt enable bit of the PIE1 register * PEIE peripheral interrupt enable bit of the INTCON register * GIE global interrupt enable bit of the INTCON register The RCIF interrupt flag bit will be set when there is an unread character in the FIFO, regardless of the state of interrupt enable bits.
DS41262D-page 154
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.1.2.4 Receive Framing Error 12.1.2.7 Address Detection
Each character in the receive FIFO buffer has a corresponding framing error status bit. A framing error indicates that a Stop bit was not seen at the expected time. The framing error status is accessed via the FERR bit of the RCSTA register. The FERR bit represents the status of the top unread character in the receive FIFO. Therefore, the FERR bit must be read before reading the RCREG. The FERR bit is read-only and only applies to the top unread character in the receive FIFO. A framing error (FERR = 1) does not preclude reception of additional characters. It is not necessary to clear the FERR bit. Reading the next character from the FIFO buffer will advance the FIFO to the next character and the next corresponding framing error. The FERR bit can be forced clear by clearing the SPEN bit of the RCSTA register which resets the EUSART. Clearing the CREN bit of the RCSTA register does not affect the FERR bit. A framing error by itself does not generate an interrupt. Note: If all receive characters in the receive FIFO have framing errors, repeated reads of the RCREG will not clear the FERR bit. A special Address Detection mode is available for use when multiple receivers share the same transmission line, such as in RS-485 systems. Address detection is enabled by setting the ADDEN bit of the RCSTA register. Address detection requires 9-bit character reception. When address detection is enabled, only characters with the ninth data bit set will be transferred to the receive FIFO buffer, thereby setting the RCIF interrupt bit. All other characters will be ignored. Upon receiving an address character, user software determines if the address matches its own. Upon address match, user software must disable address detection by clearing the ADDEN bit before the next Stop bit occurs. When user software detects the end of the message, determined by the message protocol used, software places the receiver back into the Address Detection mode by setting the ADDEN bit.
12.1.2.5
Receive Overrun Error
The receive FIFO buffer can hold two characters. An overrun error will be generated If a third character, in its entirety, is received before the FIFO is accessed. When this happens the OERR bit of the RCSTA register is set. The characters already in the FIFO buffer can be read but no additional characters will be received until the error is cleared. The error must be cleared by either clearing the CREN bit of the RCSTA register or by resetting the EUSART by clearing the SPEN bit of the RCSTA register.
12.1.2.6
Receiving 9-bit Characters
The EUSART supports 9-bit character reception. When the RX9 bit of the RCSTA register is set the EUSART will shift 9 bits into the RSR for each character received. The RX9D bit of the RCSTA register is the ninth and Most Significant data bit of the top unread character in the receive FIFO. When reading 9-bit data from the receive FIFO buffer, the RX9D data bit must be read before reading the 8 Least Significant bits from the RCREG.
(c) 2007 Microchip Technology Inc.
DS41262D-page 155
PIC16F631/677/685/687/689/690
12.1.2.8
1.
Asynchronous Reception Set-up:
12.1.2.9
9-bit Address Detection Mode Set-up
2.
3.
4. 5. 6.
7.
8.
9.
Initialize the SPBRGH, SPBRG register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 12.3 "EUSART Baud Rate Generator (BRG)"). Enable the serial port by setting the SPEN bit. The SYNC bit must be clear for asynchronous operation. If interrupts are desired, set the RCIE interrupt enable bit and set the GIE and PEIE bits of the INTCON register. If 9-bit reception is desired, set the RX9 bit. Enable reception by setting the CREN bit. The RCIF interrupt flag bit will be set when a character is transferred from the receive shift register to the receive buffer. An interrupt will be generated if the RCIE interrupt enable bit was also set. Read the RCSTA register to get the error flags and, if 9-bit data reception is enabled, the ninth data bit. Get the received 8 Least Significant data bits from the receive buffer by reading the RCREG register. If an overrun occurred, clear the OERR flag by clearing the CREN receiver enable bit.
This mode would typically be used in RS-485 systems. To set up an Asynchronous Reception with Address Detect Enable: 1. Initialize the SPBRGH, SPBRG register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 12.3 "EUSART Baud Rate Generator (BRG)"). 2. Enable the serial port by setting the SPEN bit. The SYNC bit must be clear for asynchronous operation. 3. If interrupts are desired, set the RCIE interrupt enable bit and set the GIE and PEIE bits of the INTCON register. 4. Enable 9-bit reception by setting the RX9 bit. 5. Enable address detection by setting the ADDEN bit. 6. Enable reception by setting the CREN bit. 7. The RCIF interrupt flag bit will be set when a character with the ninth bit set is transferred from the receive shift register to the receive buffer. An interrupt will be generated if the RCIE interrupt enable bit was also set. 8. Read the RCSTA register to get the error flags. The ninth data bit will always be set. 9. Get the received 8 Least Significant data bits from the receive buffer by reading the RCREG register. Software determines if this is the device's address. 10. If an overrun occurred, clear the OERR flag by clearing the CREN receiver enable bit. 11. If the device has been addressed, clear the ADDEN bit to allow all received data into the receive buffer and generate interrupts.
FIGURE 12-5:
RX/DT pin Rcv Shift Reg Rcv Buffer Reg RCIDL Read Rcv Buffer Reg RCREG RCIF (Interrupt Flag) OERR bit CREN
ASYNCHRONOUS RECEPTION
Start bit bit 0 bit 1 bit 7/8 Stop bit Start bit bit 0 bit 7/8 Stop bit Start bit bit 7/8 Stop bit
Word 1 RCREG
Word 2 RCREG
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.
DS41262D-page 156
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 12-2:
Name BAUDCTL INTCON PIE1 PIR1 RCREG RCSTA SPBRG SPBRGH TRISB TXREG TXSTA Legend:
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Bit 6 RCIDL PEIE ADIE ADIF RX9 BRG6 BRG14 TRISB6 TX9 Bit 5 -- T0IE RCIE RCIF SREN BRG5 BRG13 TRISB5 TXEN Bit 4 SCKP INTE TXIE TXIF CREN BRG4 BRG12 TRISB4 SYNC SENDB BRGH TRMT TX9D Bit 3 BRG16 RABIE SSPIE SSPIF ADDEN BRG3 BRG11 Bit 2 -- T0IF CCP1IE CCP1IF FERR BRG2 BRG10 Bit 1 WUE INTF TMR2IE TMR2IF OERR BRG1 BRG9 Bit 0 ABDEN RABIF TMR1IE TMR1IF RX9D BRG0 BRG8 Value on POR, BOR 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010
Bit 7 ABDOVF GIE -- -- SPEN BRG7 BRG15 TRISB7 CSRC
EUSART Receive Data Register
EUSART Transmit Data Register
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for Asynchronous Reception.
(c) 2007 Microchip Technology Inc.
DS41262D-page 157
PIC16F631/677/685/687/689/690
12.2 Clock Accuracy with Asynchronous Operation
The first (preferred) method uses the OSCTUNE register to adjust the INTOSC output. Adjusting the value in the OSCTUNE register allows for fine resolution changes to the system clock source. See Section 3.5 "Internal Clock Modes" for more information. The other method adjusts the value in the Baud Rate Generator. This can be done automatically with the Auto-Baud Detect feature (see Section 12.3.1 "Auto-Baud Detect"). There may not be fine enough resolution when adjusting the Baud Rate Generator to compensate for a gradual change in the peripheral clock frequency.
The factory calibrates the internal oscillator block output (INTOSC). However, the INTOSC frequency may drift as VDD or temperature changes, and this directly affects the asynchronous baud rate. Two methods may be used to adjust the baud rate clock, but both require a reference clock source of some kind.
REGISTER 12-1:
R/W-0 CSRC bit 7 Legend: R = Readable bit -n = Value at POR bit 7
TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-0 TX9 R/W-0 TXEN
(1)
R/W-0 SYNC
R/W-0 SENDB
R/W-0 BRGH
R-1 TRMT
R/W-0 TX9D bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
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) 1 = Transmit enabled 0 = Transmit disabled SYNC: EUSART Mode Select bit 1 = Synchronous mode 0 = Asynchronous mode SENDB: Send Break Character bit Asynchronous mode: 1 = Send Sync Break on next transmission (cleared by hardware upon completion) 0 = Sync Break transmission completed Synchronous mode: Don't care 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: Ninth bit of Transmit Data Can be address/data bit or a parity bit. SREN/CREN overrides TXEN in Sync mode.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1:
DS41262D-page 158
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 12-2:
R/W-0 SPEN bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
RCSTA: RECEIVE STATUS AND CONTROL REGISTER(1)
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 (held in Reset) 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, enable interrupt and load 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 Asynchronous mode 8-bit (RX9 = 0): Don't care 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: Ninth bit of Received Data This can be address/data bit or a parity bit and must be calculated by user firmware.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
(c) 2007 Microchip Technology Inc.
DS41262D-page 159
PIC16F631/677/685/687/689/690
REGISTER 12-3:
R-0 ABDOVF bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
BAUDCTL: BAUD RATE CONTROL REGISTER
R-1 RCIDL U-0 -- R/W-0 SCKP R/W-0 BRG16 U-0 -- R/W-0 WUE R/W-0 ABDEN bit 0
ABDOVF: Auto-Baud Detect Overflow bit Asynchronous mode: 1 = Auto-baud timer overflowed 0 = Auto-baud timer did not overflow Synchronous mode: Don't care RCIDL: Receive Idle Flag bit Asynchronous mode: 1 = Receiver is Idle 0 = Start bit has been received and the receiver is receiving Synchronous mode: Don't care Unimplemented: Read as `0' SCKP: Synchronous Clock Polarity Select bit Asynchronous mode: 1 = Transmit inverted data to the RB7/TX/CK pin 0 = Transmit non-inverted data to the RB7/TX/CK pin Synchronous mode: 1 = Data is clocked on rising edge of the clock 0 = Data is clocked on falling edge of the clock BRG16: 16-bit Baud Rate Generator bit 1 = 16-bit Baud Rate Generator is used 0 = 8-bit Baud Rate Generator is used Unimplemented: Read as `0' WUE: Wake-up Enable bit Asynchronous mode: 1 = Receiver is waiting for a falling edge. No character will be received byte RCIF will be set. WUE will automatically clear after RCIF is set. 0 = Receiver is operating normally Synchronous mode: Don't care ABDEN: Auto-Baud Detect Enable bit Asynchronous mode: 1 = Auto-Baud Detect mode is enabled (clears when auto-baud is complete) 0 = Auto-Baud Detect mode is disabled Synchronous mode: Don't care
bit 6
bit 5 bit 4
bit 3
bit 2 bit 1
bit 0
DS41262D-page 160
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.3 EUSART Baud Rate Generator (BRG)
If the system clock is changed during an active receive operation, a receive error or data loss may result. To avoid this problem, check the status of the RCIDL bit to make sure that the receive operation is Idle before changing the system clock.
The Baud Rate Generator (BRG) is an 8-bit or 16-bit timer that is dedicated to the support of both the asynchronous and synchronous EUSART operation. By default, the BRG operates in 8-bit mode. Setting the BRG16 bit of the BAUDCTL register selects 16-bit mode. The SPBRGH, SPBRG register pair determines the period of the free running baud rate timer. In Asynchronous mode the multiplier of the baud rate period is determined by both the BRGH bit of the TXSTA register and the BRG16 bit of the BAUDCTL register. In Synchronous mode, the BRGH bit is ignored. Table 12-3 contains the formulas for determining the baud rate. Example 12-1 provides a sample calculation for determining the baud rate and baud rate error. Typical baud rates and error values for various asynchronous modes have been computed for your convenience and are shown in Table 12-3. It may be advantageous to use the high baud rate (BRGH = 1), or the 16-bit BRG (BRG16 = 1) to reduce the baud rate error. The 16-bit BRG mode is used to achieve slow baud rates for fast oscillator frequencies. Writing a new value to the SPBRGH, SPBRG register pair causes the BRG timer to be reset (or cleared). This ensures that the BRG does not wait for a timer overflow before outputting the new baud rate.
EXAMPLE 12-1:
CALCULATING BAUD RATE ERROR
For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG:
FOSC Desired Baud Rate = -------------------------------------------------------------------64 ( [SPBRGH:SPBRG] + 1 )
Solving for SPBRGH:SPBRG:
FOSC -------------------------------------------Desired Baud Rate X = --------------------------------------------- - 1 64 16000000 ----------------------9600 = ----------------------- - 1 64 = [ 25.042 ] = 25 16000000Calculated Baud Rate = -------------------------64 ( 25 + 1 ) = 9615 Calc. Baud Rate - Desired Baud RateError = ------------------------------------------------------------------------------------------Desired Baud Rate ( 9615 - 9600 ) = ---------------------------------- = 0.16% 9600
TABLE 12-3:
SYNC 0 0 0 0 1 1 Legend:
BAUD RATE FORMULAS
BRG/EUSART Mode BRG16 0 0 1 1 0 1 BRGH 0 1 0 1 x x 8-bit/Asynchronous 8-bit/Asynchronous FOSC/[16 (n+1)] 16-bit/Asynchronous 16-bit/Asynchronous 8-bit/Synchronous 16-bit/Synchronous FOSC/[4 (n+1)] FOSC/[64 (n+1)] Baud Rate Formula
Configuration Bits
x = Don't care, n = value of SPBRGH, SPBRG register pair
TABLE 12-4:
Name BAUDCTL RCSTA SPBRG SPBRGH TXSTA Legend:
REGISTERS ASSOCIATED WITH THE BAUD RATE GENERATOR
Bit 6 RCIDL RX9 BRG6 BRG14 TX9 Bit 5 -- SREN BRG5 BRG13 TXEN Bit 4 SCKP CREN BRG4 BRG12 SYNC Bit 3 BRG16 ADDEN BRG3 BRG11 SENDB Bit 2 -- FERR BRG2 BRG10 BRGH Bit 1 WUE OERR BRG1 BRG9 TRMT Bit 0 ABDEN RX9D BRG0 BRG8 TX9D Value on POR, BOR 01-0 0-00 0000 000x 0000 0000 0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x 0000 0000 0000 0000 0000 0010
Bit 7 ABDOVF SPEN BRG7 BRG15 CSRC
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for the Baud Rate Generator.
(c) 2007 Microchip Technology Inc.
DS41262D-page 161
PIC16F631/677/685/687/689/690
TABLE 12-5: BAUD RATES FOR ASYNCHRONOUS MODES
SYNC = 0, BRGH = 0, BRG16 = 0 BAUD RATE FOSC = 20.000 MHz Actual Rate -- 1221 2404 9470 10417 19.53k -- -- % Error -- 1.73 0.16 -1.36 0.00 1.73 -- -- SPBRG value (decimal) -- 255 129 32 29 15 -- -- FOSC = 18.432 MHz Actual Rate -- 1200 2400 9600 10286 19.20k 57.60k -- % Error -- 0.00 0.00 0.00 -1.26 0.00 0.00 -- SPBRG value (decimal) -- 239 119 29 27 14 7 -- FOSC = 11.0592 MHz Actual Rate -- 1200 2400 9600 10165 19.20k 57.60k -- % Error -- 0.00 0.00 0.00 -2.42 0.00 0.00 -- SPBRG value (decimal) -- 143 71 17 16 8 2 -- FOSC = 8.000 MHz Actual Rate -- 1202 2404 9615 10417 -- -- -- % Error -- 0.16 0.16 0.16 0.00 -- -- -- SPBRG value (decimal) -- 103 51 12 11 -- -- --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
SYNC = 0, BRGH = 0, BRG16 = 0 BAUD RATE FOSC = 4.000 MHz Actual Rate 300 1202 2404 -- 10417 -- -- -- % Error 0.16 0.16 0.16 -- 0.00 -- -- -- SPBRG value (decimal) 207 51 25 -- 5 -- -- -- FOSC = 3.6864 MHz Actual Rate 300 1200 2400 9600 -- 19.20k 57.60k -- % Error 0.00 0.00 0.00 0.00 -- 0.00 0.00 -- SPBRG value (decimal) 191 47 23 5 -- 2 0 -- FOSC = 2.000 MHz Actual Rate 300 1202 2404 -- 10417 -- -- -- % Error 0.16 0.16 0.16 -- 0.00 -- -- -- SPBRG value (decimal) 103 25 12 -- 2 -- -- -- FOSC = 1.000 MHz Actual Rate 300 1202 -- -- -- -- -- -- % Error 0.16 0.16 -- -- -- -- -- -- SPBRG value (decimal) 51 12 -- -- -- -- -- --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
SYNC = 0, BRGH = 1, BRG16 = 0 BAUD RATE FOSC = 20.000 MHz Actual Rate -- -- -- 9615 10417 19.23k 56.82k 113.64k % Error -- -- -- 0.16 0.00 0.16 -1.36 -1.36 SPBRG value (decimal) -- -- -- 129 119 64 21 10 FOSC = 18.432 MHz Actual Rate -- -- -- 9600 10378 19.20k 57.60k 115.2k % Error -- -- -- 0.00 -0.37 0.00 0.00 0.00 SPBRG value (decimal) -- -- -- 119 110 59 19 9 FOSC = 11.0592 MHz Actual Rate -- -- -- 9600 10473 19.20k 57.60k 115.2k % Error -- -- -- 0.00 0.53 0.00 0.00 0.00 SPBRG value (decimal) -- -- -- 71 65 35 11 5 FOSC = 8.000 MHz Actual Rate -- -- 2404 9615 10417 19231 55556 -- % Error -- -- 0.16 0.16 0.00 0.16 -3.55 -- SPBRG value (decimal) -- -- 207 51 47 25 8 --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
DS41262D-page 162
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 12-5: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 0 BAUD RATE FOSC = 4.000 MHz Actual Rate -- 1202 2404 9615 10417 19.23k -- -- % Error -- 0.16 0.16 0.16 0.00 0.16 -- -- SPBRG value (decimal) -- 207 103 25 23 12 -- -- FOSC = 3.6864 MHz Actual Rate -- 1200 2400 9600 10473 19.2k 57.60k 115.2k % Error -- 0.00 0.00 0.00 0.53 0.00 0.00 0.00 SPBRG value (decimal) -- 191 95 23 21 11 3 1 FOSC = 2.000 MHz Actual Rate -- 1202 2404 9615 10417 -- -- -- % Error -- 0.16 0.16 0.16 0.00 -- -- -- SPBRG value (decimal) -- 103 51 12 11 -- -- -- FOSC = 1.000 MHz Actual Rate 300 1202 2404 -- 10417 -- -- -- % Error 0.16 0.16 0.16 -- 0.00 -- -- -- SPBRG value (decimal) 207 51 25 -- 5 -- -- --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
SYNC = 0, BRGH = 0, BRG16 = 1 BAUD RATE FOSC = 20.000 MHz Actual Rate 300.0 1200 2399 9615 10417 19.23k 56.818 113.636 % Error -0.01 -0.03 -0.03 0.16 0.00 0.16 -1.36 -1.36 SPBRG value (decimal) 4166 1041 520 129 119 64 21 10 FOSC = 18.432 MHz Actual Rate 300.0 1200 2400 9600 10378 19.20k 57.60k 115.2k % Error 0.00 0.00 0.00 0.00 -0.37 0.00 0.00 0.00 SPBRG value (decimal) 3839 959 479 119 110 59 19 9 FOSC = 11.0592 MHz Actual Rate 300.0 1200 2400 9600 10473 19.20k 57.60k 115.2k % Error 0.00 0.00 0.00 0.00 0.53 0.00 0.00 0.00 SPBRG value (decimal) 2303 575 287 71 65 35 11 5 FOSC = 8.000 MHz Actual Rate 299.9 1199 2404 9615 10417 19.23k 55556 -- % Error -0.02 -0.08 0.16 0.16 0.00 0.16 -3.55 -- SPBRG value (decimal) 1666 416 207 51 47 25 8 --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
SYNC = 0, BRGH = 0, BRG16 = 1 BAUD RATE FOSC = 4.000 MHz Actual Rate 300.1 1202 2404 9615 10417 19.23k -- -- % Error 0.04 0.16 0.16 0.16 0.00 0.16 -- -- SPBRG value (decimal) 832 207 103 25 23 12 -- -- FOSC = 3.6864 MHz Actual Rate 300.0 1200 2400 9600 10473 19.20k 57.60k 115.2k % Error 0.00 0.00 0.00 0.00 0.53 0.00 0.00 0.00 SPBRG value (decimal) 767 191 95 23 21 11 3 1 FOSC = 2.000 MHz Actual Rate 299.8 1202 2404 9615 10417 -- -- -- % Error -0.108 0.16 0.16 0.16 0.00 -- -- -- SPBRG value (decimal) 416 103 51 12 11 -- -- -- FOSC = 1.000 MHz Actual Rate 300.5 1202 2404 -- 10417 -- -- -- % Error 0.16 0.16 0.16 -- 0.00 -- -- -- SPBRG value (decimal) 207 51 25 -- 5 -- -- --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
(c) 2007 Microchip Technology Inc.
DS41262D-page 163
PIC16F631/677/685/687/689/690
TABLE 12-5: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1 BAUD RATE FOSC = 20.000 MHz Actual Rate 300.0 1200 2400 9597 10417 19.23k 57.47k 116.3k % Error 0.00 -0.01 0.02 -0.03 0.00 0.16 -0.22 0.94 SPBRG value (decimal) 16665 4166 2082 520 479 259 86 42 FOSC = 18.432 MHz Actual Rate 300.0 1200 2400 9600 10425 19.20k 57.60k 115.2k % Error 0.00 0.00 0.00 0.00 0.08 0.00 0.00 0.00 SPBRG value (decimal) 15359 3839 1919 479 441 239 79 39 FOSC = 11.0592 MHz Actual Rate 300.0 1200 2400 9600 10433 19.20k 57.60k 115.2k % Error 0.00 0.00 0.00 0.00 0.16 0.00 0.00 0.00 SPBRG value (decimal) 9215 2303 1151 287 264 143 47 23 FOSC = 8.000 MHz Actual Rate 300.0 1200 2401 9615 10417 19.23k 57.14k 117.6k % Error 0.00 -0.02 0.04 0.16 0 0.16 -0.79 2.12 SPBRG value (decimal) 6666 1666 832 207 191 103 34 16
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1 BAUD RATE FOSC = 4.000 MHz Actual Rate 300.0 1200 2398 9615 10417 19.23k 58.82k 111.1k % Error 0.01 0.04 0.08 0.16 0.00 0.16 2.12 -3.55 SPBRG value (decimal) 3332 832 416 103 95 51 16 8 FOSC = 3.6864 MHz Actual Rate 300.0 1200 2400 9600 10473 19.20k 57.60k 115.2k % Error 0.00 0.00 0.00 0.00 0.53 0.00 0.00 0.00 SPBRG value (decimal) 3071 767 383 95 87 47 15 7 FOSC = 2.000 MHz Actual Rate 299.9 1199 2404 9615 10417 19.23k 55.56k -- % Error -0.02 -0.08 0.16 0.16 0.00 0.16 -3.55 -- SPBRG value (decimal) 1666 416 207 51 47 25 8 -- FOSC = 1.000 MHz Actual Rate 300.1 1202 2404 9615 10417 19.23k -- -- % Error 0.04 0.16 0.16 0.16 0.00 0.16 -- -- SPBRG value (decimal) 832 207 103 25 23 12 -- --
300 1200 2400 9600 10417 19.2k 57.6k 115.2k
DS41262D-page 164
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.3.1 AUTO-BAUD DETECT
The EUSART module supports automatic detection and calibration of the baud rate. In the Auto-Baud Detect (ABD) mode, the clock to the BRG is reversed. Rather than the BRG clocking the incoming RX signal, the RX signal is timing the BRG. The Baud Rate Generator is used to time the period of a received 55h (ASCII "U") which is the Sync character for the LIN bus. The unique feature of this character is that it has five rising edges including the Stop bit edge. Setting the ABDEN bit of the BAUDCTL register starts the auto-baud calibration sequence (Figure 12-6). While the ABD sequence takes place, the EUSART state machine is held in Idle. On the first rising edge of the receive line, after the Start bit, the SPBRG begins counting up using the BRG counter clock as shown in Table 12-6. The fifth rising edge will occur on the RX pin at the end of the eighth bit period. At that time, an accumulated value totaling the proper BRG period is left in the SPBRGH, SPBRG register pair, the ABDEN bit is automatically cleared and the RCIF interrupt flag is set. The value in the RCREG needs to be read to clear the RCIF interrupt. RCREG content should be discarded. When calibrating for modes that do not use the SPBRGH register the user can verify that the SPBRG register did not overflow by checking for 00h in the SPBRGH register. The BRG auto-baud clock is determined by the BRG16 and BRGH bits as shown in Table 12-6. During ABD, both the SPBRGH and SPBRG registers are used as a 16-bit counter, independent of the BRG16 bit setting. While calibrating the baud rate period, the SPBRGH and SPBRG registers are clocked at 1/8th the BRG base clock rate. The resulting byte measurement is the average bit time when clocked at full speed. Note 1: If the WUE bit is set with the ABDEN bit, auto-baud detection will occur on the byte following the Break character (see Section 12.3.2 "Auto-Wake-up on Break"). 2: It is up to the user to determine that the incoming character baud rate is within the range of the selected BRG clock source. Some combinations of oscillator frequency and EUSART baud rates are not possible. 3: During the auto-baud process, the auto-baud counter starts counting at 1. Upon completion of the auto-baud sequence, to achieve maximum accuracy, subtract 1 from the SPBRGH:SPBRG register pair.
TABLE 12-6:
BRG16 0 0 1 1 Note: BRGH 0 1 0 1
BRG COUNTER CLOCK RATES
BRG Base Clock FOSC/64 FOSC/16 FOSC/16 FOSC/4 BRG ABD Clock FOSC/512 FOSC/128 FOSC/128 FOSC/32
During the ABD sequence, SPBRG and SPBRGH registers are both used as a 16-bit counter, independent of BRG16 setting.
FIGURE 12-6:
BRG Value RX pin
AUTOMATIC BAUD RATE CALIBRATION
XXXXh 0000h Edge #1 bit 1 Edge #2 bit 3 Edge #3 bit 5 Edge #4 bit 7 001Ch Edge #5 Stop bit
Start
bit 0
bit 2
bit 4
bit 6
BRG Clock Set by User ABDEN bit RCIDL RCIF bit (Interrupt) Read RCREG SPBRG SPBRGH Note 1: XXh XXh The ABD sequence requires the EUSART module to be configured in Asynchronous mode. 1Ch 00h Auto Cleared
(c) 2007 Microchip Technology Inc.
DS41262D-page 165
PIC16F631/677/685/687/689/690
12.3.2 AUTO-WAKE-UP ON BREAK 12.3.2.1 Special Considerations
During Sleep mode, all clocks to the EUSART are suspended. Because of this, the Baud Rate Generator is inactive and a proper character reception cannot be performed. The Auto-Wake-up feature allows the controller to wake-up due to activity on the RX/DT line. This feature is available only in Asynchronous mode. The Auto-Wake-up feature is enabled by setting the WUE bit of the BAUDCTL register. Once set, the normal receive sequence on RX/DT is disabled, and the EUSART remains in an Idle state, monitoring for a wake-up event independent of the CPU mode. A wake-up event consists of a high-to-low transition on the RX/DT line. (This coincides with the start of a Sync Break or a wake-up signal character for the LIN protocol.) The EUSART module generates an RCIF interrupt coincident with the wake-up event. The interrupt is generated synchronously to the Q clocks in normal CPU operating modes (Figure 12-7), and asynchronously if the device is in Sleep mode (Figure 12-8). The interrupt condition is cleared by reading the RCREG register. The WUE bit is automatically cleared by the low-to-high transition on the RX line at the end of the Break. This signals to the user that the Break event is over. At this point, the EUSART module is in Idle mode waiting to receive the next character. Break Character To avoid character errors or character fragments during a wake-up event, the wake-up character must be all zeros. When the wake-up is enabled the function works independent of the low time on the data stream. If the WUE bit is set and a valid non-zero character is received, the low time from the Start bit to the first rising edge will be interpreted as the wake-up event. The remaining bits in the character will be received as a fragmented character and subsequent characters can result in framing or overrun errors. Therefore, the initial character in the transmission must be all `0's. This must be 10 or more bit times, 13-bit times recommended for LIN bus, or any number of bit times for standard RS-232 devices. Oscillator Startup Time Oscillator start-up time must be considered, especially in applications using oscillators with longer start-up intervals (i.e., LP, XT or HS/PLL mode). The Sync Break (or wake-up signal) character must be of sufficient length, and be followed by a sufficient interval, to allow enough time for the selected oscillator to start and provide proper initialization of the EUSART. WUE Bit The wake-up event causes a receive interrupt by setting the RCIF bit. The WUE bit is cleared in hardware by a rising edge on RX/DT. The interrupt condition is then cleared in software by reading the RCREG register and discarding its contents. To ensure that no actual data is lost, check the RCIDL bit to verify that a receive operation is not in process before setting the WUE bit. If a receive operation is not occurring, the WUE bit may then be set just prior to entering the Sleep mode.
FIGURE 12-7:
OSC1
AUTO-WAKE-UP BIT (WUE) TIMING DURING NORMAL OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Bit set by user WUE bit RX/DT Line RCIF Auto Cleared
Cleared due to User Read of RCREG The EUSART remains in Idle while the WUE bit is set.
Note 1:
DS41262D-page 166
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 12-8:
OSC1 Bit Set by User WUE bit RX/DT Line RCIF Sleep Command Executed Note 1: 2: Sleep Ends Note 1 Cleared due to User Read of RCREG Auto Cleared
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4
Q1Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4
If the wake-up event requires long oscillator warm-up time, the automatic clearing of the WUE bit can occur while the stposc signal is still active. This sequence should not depend on the presence of Q clocks. The EUSART remains in Idle while the WUE bit is set.
12.3.3
BREAK CHARACTER SEQUENCE
12.3.4
RECEIVING A BREAK CHARACTER
The EUSART module has the capability of sending the special Break character sequences that are required by the LIN bus standard. A Break character consists of a Start bit, followed by 12 `0' bits and a Stop bit. To send a Break character, set the SENDB and TXEN bits of the TXSTA register. The Break character transmission is then initiated by a write to the TXREG. The value of data written to TXREG will be ignored and all `0's will be transmitted. The SENDB bit is automatically reset by hardware after the corresponding Stop bit is sent. This allows the user to preload the transmit FIFO with the next transmit byte following the Break character (typically, the Sync character in the LIN specification). The TRMT bit of the TXSTA register indicates when the transmit operation is active or Idle, just as it does during normal transmission. See Figure 12-9 for the timing of the Break character sequence.
The Enhanced EUSART module can receive a Break character in two ways. The first method to detect a Break character uses the FERR bit of the RCSTA register and the Received data as indicated by RCREG. The Baud Rate Generator is assumed to have been initialized to the expected baud rate. A Break character has been received when; * RCIF bit is set * FERR bit is set * RCREG = 00h The second method uses the Auto-Wake-up feature described in Section 12.3.2 "Auto-Wake-up on Break". By enabling this feature, the EUSART will sample the next two transitions on RX/DT, cause an RCIF interrupt, and receive the next data byte followed by another interrupt. Note that following a Break character, the user will typically want to enable the Auto-Baud Detect feature. For both methods, the user can set the ABDEN bit of the BAUDCTL register before placing the EUSART in Sleep mode.
12.3.3.1
Break and Sync Transmit Sequence
The following sequence will start a message frame header made up of a Break, followed by an auto-baud Sync byte. This sequence is typical of a LIN bus master. 1. 2. 3. 4. 5. Configure the EUSART for the desired mode. Set the TXEN and SENDB bits to enable the Break sequence. Load the TXREG with a dummy character to initiate transmission (the value is ignored). Write `55h' to TXREG to load the Sync character into the transmit FIFO buffer. After the Break has been sent, the SENDB bit is reset by hardware and the Sync character is then transmitted.
When the TXREG becomes empty, as indicated by the TXIF, the next data byte can be written to TXREG.
(c) 2007 Microchip Technology Inc.
DS41262D-page 167
PIC16F631/677/685/687/689/690
FIGURE 12-9:
Write to TXREG BRG Output (Shift Clock) TX (pin) Start bit bit 0 bit 1 Break TXIF bit (Transmit interrupt Flag) TRMT bit (Transmit Shift Reg. Empty Flag) bit 11 Stop bit
SEND BREAK CHARACTER SEQUENCE
Dummy Write
SENDB Sampled Here
SENDB
(send Break control bit)
Auto Cleared
DS41262D-page 168
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.4 EUSART Synchronous Mode
Synchronous serial communications are typically used in systems with a single master and one or more slaves. The master device contains the necessary circuitry for baud rate generation and supplies the clock for all devices in the system. Slave devices can take advantage of the master clock by eliminating the internal clock generation circuitry. There are two signal lines in Synchronous mode: a bidirectional data line and a clock line. Slaves use the external clock supplied by the master to shift the serial data into and out of their respective receive and transmit shift registers. Since the data line is bidirectional, synchronous operation is half-duplex only. Half-duplex refers to the fact that master and slave devices can receive and transmit data but not both simultaneously. The EUSART can operate as either a master or slave device. Start and Stop bits are not used in synchronous transmissions. the clock Idle state as high. When the SCKP bit is set, the data changes on the falling edge of each clock. Clearing the SCKP bit sets the Idle state as low. When the SCKP bit is cleared, the data changes on the rising edge of each clock.
12.4.1.3
Synchronous Master Transmission
Data is transferred out of the device on the RX/DT pin. The RX/DT and TX/CK pin output drivers are automatically enabled when the EUSART is configured for synchronous master transmit operation. A transmission is initiated by writing a character to the TXREG register. If the TSR still contains all or part of a previous character the new character data is held in the TXREG until the last bit of the previous character has been transmitted. If this is the first character, or the previous character has been completely flushed from the TSR, the data in the TXREG is immediately transferred to the TSR. The transmission of the character commences immediately following the transfer of the data to the TSR from the TXREG. Each data bit changes on the leading edge of the master clock and remains valid until the subsequent leading clock edge. Note: The TSR register is not mapped in data memory, so it is not available to the user.
12.4.1
SYNCHRONOUS MASTER MODE
The following bits are used to configure the EUSART for Synchronous Master operation: * * * * * SYNC = 1 CSRC = 1 SREN = 0 (for transmit); SREN = 1 (for receive) CREN = 0 (for transmit); CREN = 1 (for receive) SPEN = 1
12.4.1.4
1.
Synchronous Master Transmission Set-up:
Setting the SYNC bit of the TXSTA register configures the device for synchronous operation. Setting the CSRC bit of the TXSTA register configures the device as a master. Clearing the SREN and CREN bits of the RCSTA register ensures that the device is in the Transmit mode, otherwise the device will be configured to receive. Setting the SPEN bit of the RCSTA register enables the EUSART. If the RX/DT or TX/CK pins are shared with an analog peripheral the analog I/O functions must be disabled by clearing the corresponding ANSEL bits.
2. 3. 4. 5. 6. 7. 8.
12.4.1.1
Master Clock
Synchronous data transfers use a separate clock line, which is synchronous with the data. A device configured as a master transmits the clock on the TX/CK line. The TX/CK pin is automatically configured as an output when the EUSART is configured for synchronous transmit operation. Serial data bits change on the leading edge to ensure they are valid at the trailing edge of each clock. One clock cycle is generated for each data bit. Only as many clock cycles are generated as there are data bits.
Initialize the SPBRGH, SPBRG register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 12.3 "EUSART Baud Rate Generator (BRG)"). Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC. Disable Receive mode by clearing bits SREN and CREN. Enable Transmit mode by setting the TXEN bit. If 9-bit transmission is desired, set the TX9 bit. If interrupts are desired, set the TXIE, GIE and PEIE interrupt enable bits. If 9-bit transmission is selected, the ninth bit should be loaded in the TX9D bit. Start transmission by loading data to the TXREG register.
12.4.1.2
Clock Polarity
A clock polarity option is provided for Microwire compatability. Clock polarity is selected with the SCKP bit of the BAUDCTL register. Setting the SCKP bit sets
(c) 2007 Microchip Technology Inc.
DS41262D-page 169
PIC16F631/677/685/687/689/690
FIGURE 12-10: SYNCHRONOUS TRANSMISSION
RX/DT pin TX/CK pin (SCKP = 0) TX/CK pin (SCKP = 1) Write to TXREG Reg TXIF bit (Interrupt Flag) TRMT bit Write Word 1
bit 0
bit 1 Word 1
bit 2
bit 7
bit 0
bit 1 Word 2
bit 7
Write Word 2
TXEN bit Note:
`1' Sync Master mode, SPBRG = 0, continuous transmission of two 8-bit words.
`1'
FIGURE 12-11:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
RX/DT pin bit 0 bit 1 bit 2 bit 6 bit 7
TX/CK pin Write to TXREG reg
TXIF bit
TRMT bit
TXEN bit
TABLE 12-7:
Name BAUDCTL INTCON PIE1 PIR1 RCREG RCSTA SPBRG SPBRGH TRISB TXREG TXSTA Legend:
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Bit 6 RCIDL PEIE ADIE ADIF RX9 BRG6 BRG14 TRISB6 TX9 Bit 5 -- T0IE RCIE RCIF SREN BRG5 BRG13 TRISB5 TXEN Bit 4 SCKP INTE TXIE TXIF CREN BRG4 BRG12 TRISB4 SYNC SENDB BRGH TRMT TX9D Bit 3 BRG16 RABIE SSPIE SSPIF ADDEN BRG3 BRG11 Bit 2 -- T0IF CCP1IE CCP1IF FERR BRG2 BRG10 Bit 1 WUE INTF TMR2IE TMR2IF OERR BRG1 BRG9 Bit 0 ABDEN RABIF TMR1IE TMR1IF RX9D BRG0 BRG8 Value on POR, BOR 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010
Bit 7 ABDOVF GIE -- -- SPEN BRG7 BRG15 TRISB7 CSRC
EUSART Receive Data Register
EUSART Transmit Data Register
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for Synchronous Master Transmission.
DS41262D-page 170
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.4.1.5 Synchronous Master Reception 12.4.1.8
1. Data is received at the RX/DT pin. The RX/DT and TX/CK pin output drivers are automatically disabled when the EUSART is configured for synchronous master receive operation. In Synchronous mode, reception is enabled by setting either the Single Receive Enable bit (SREN of the RCSTA register) or the Continuous Receive Enable bit (CREN of the RCSTA register). When SREN is set and CREN is clear, only as many clock cycles are generated as there are data bits in a single character. The SREN bit is automatically cleared at the completion of one character. When CREN is set, clocks are continuously generated until CREN is cleared. If CREN is cleared in the middle of a character the CK clock stops immediately and the partial character is discarded. If SREN and CREN are both set, then SREN is cleared at the completion of the first character and CREN takes precedence. To initiate reception, set either SREN or CREN. Data is sampled at the RX/DT pin on the trailing edge of the TX/CK clock pin and is shifted into the Receive Shift Register (RSR). When a complete character is received into the RSR, the RCIF bit is set and the character is automatically transferred to the two character receive FIFO. The Least Significant eight bits of the top character in the receive FIFO are available in RCREG. The RCIF bit remains set as long as there are un-read characters in the receive FIFO.
Synchronous Master Reception Set-up:
Initialize the SPBRGH, SPBRG register pair for the appropriate baud rate. Set or clear the BRGH and BRG16 bits, as required, to achieve the desired baud rate. 2. Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC. 3. Ensure bits CREN and SREN are clear. 4. If using interrupts, set the GIE and PEIE bits of the INTCON register and set RCIE. 5. If 9-bit reception is desired, set bit RX9. 6. Start reception by setting the SREN bit or for continuous reception, set the CREN bit. 7. Interrupt flag bit RCIF will be set when reception of a character is complete. An interrupt will be generated if the enable bit RCIE was set. 8. Read the RCSTA 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 RCREG register. 10. If an overrun error occurs, clear the error by either clearing the CREN bit of the RCSTA register or by clearing the SPEN bit which resets the EUSART.
12.4.1.6
Receive Overrun Error
The receive FIFO buffer can hold two characters. An overrun error will be generated if a third character, in its entirety, is received before RCREG is read to access the FIFO. When this happens the OERR bit of the RCSTA register is set. Previous data in the FIFO will not be overwritten. The two characters in the FIFO buffer can be read, however, no additional characters will be received until the error is cleared. The OERR bit can only be cleared by clearing the overrun condition. If the overrun error occurred when the SREN bit is set and CREN is clear then the error is cleared by reading RCREG. If the overrun occurred when the CREN bit is set then the error condition is cleared by either clearing the CREN bit of the RCSTA register or by clearing the SPEN bit which resets the EUSART.
12.4.1.7
Receiving 9-bit Characters
The EUSART supports 9-bit character reception. When the RX9 bit of the RCSTA register is set the EUSART will shift 9-bits into the RSR for each character received. The RX9D bit of the RCSTA register is the ninth, and Most Significant, data bit of the top unread character in the receive FIFO. When reading 9-bit data from the receive FIFO buffer, the RX9D data bit must be read before reading the 8 Least Significant bits from the RCREG.
(c) 2007 Microchip Technology Inc.
DS41262D-page 171
PIC16F631/677/685/687/689/690
FIGURE 12-12:
RX/DT pin TX/CK pin (SCKP = 0) TX/CK pin (SCKP = 1) Write to bit SREN SREN bit CREN bit RCIF bit (Interrupt) Read RXREG Note: Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0. `0' `0'
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
TABLE 12-8:
Name BAUDCTL INTCON PIE1 PIR1 RCREG RCSTA SPBRG SPBRGH TRISB TXREG TXSTA Legend:
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
Bit 6 RCIDL PEIE ADIE ADIF RX9 BRG6 BRG14 TRISB6 TX9 Bit 5 -- T0IE RCIE RCIF SREN BRG5 BRG13 TRISB5 TXEN Bit 4 SCKP INTE TXIE TXIF CREN BRG4 BRG12 TRISB4 SYNC SENDB BRGH TRMT TX9D Bit 3 BRG16 RABIE SSPIE SSPIF ADDEN BRG3 BRG11 Bit 2 -- T0IF CCP1IE CCP1IF FERR BRG2 BRG10 Bit 1 WUE INTF TMR2IE TMR2IF OERR BRG1 BRG9 Bit 0 ABDEN RABIF TMR1IE TMR1IF RX9D BRG0 BRG8 Value on POR, BOR 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010
Bit 7 ABDOVF GIE -- -- SPEN BRG7 BRG15 TRISB7 CSRC
EUSART Receive Data Register
EUSART Transmit Data Register
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for Synchronous Master Reception.
DS41262D-page 172
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
12.4.2 SYNCHRONOUS SLAVE MODE
The following bits are used to configure the EUSART for Synchronous slave operation: * * * * * SYNC = 1 CSRC = 0 SREN = 0 (for transmit); SREN = 1 (for receive) CREN = 0 (for transmit); CREN = 1 (for receive) SPEN = 1 If two words are written to the TXREG and then the SLEEP instruction is executed, the following will occur: 1. 2. 3. 4. The first character will immediately transfer to the TSR register and transmit. The second word will remain in TXREG register. The TXIF bit will not be set. After the first character has been shifted out of TSR, the TXREG register will transfer the second character to the TSR and the TXIF bit will now be set. If the PEIE and TXIE bits are set, the interrupt will wake the device from Sleep and execute the next instruction. If the GIE bit is also set, the program will call the interrupt service routine.
Setting the SYNC bit of the TXSTA register configures the device for synchronous operation. Clearing the CSRC bit of the TXSTA register configures the device as a slave. Clearing the SREN and CREN bits of the RCSTA register ensures that the device is in the Transmit mode, otherwise the device will be configured to receive. Setting the SPEN bit of the RCSTA register enables the EUSART. If the RX/DT or TX/CK pins are shared with an analog peripheral the analog I/O functions must be disabled by clearing the corresponding ANSEL bits.
5.
12.4.2.2
1. 2. 3.
Synchronous Slave Transmission Set-up:
12.4.2.1
EUSART Synchronous Slave Transmit
The operation of the Synchronous Master and Slave modes are identical (see Section 12.4.1.3 "Synchronous Master Transmission"), except in the case of the Sleep mode.
4. 5. 6. 7.
Set the SYNC and SPEN bits and clear the CSRC bit. Clear the CREN and SREN bits. If using interrupts, ensure that the GIE and PEIE bits of the INTCON register are set and set the TXIE bit. If 9-bit transmission is desired, set the TX9 bit. Enable transmission by setting the TXEN bit. If 9-bit transmission is selected, insert the Most Significant bit into the TX9D bit. Start transmission by writing the Least Significant 8 bits to the TXREG register.
TABLE 12-9:
Name BAUDCTL INTCON PIE1 PIR1 RCREG RCSTA SPBRG SPBRGH TRISB TXREG TXSTA Legend:
REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Bit 6 RCIDL PEIE ADIE ADIF RX9 BRG6 BRG14 TRISB6 TX9 Bit 5 -- T0IE RCIE RCIF SREN BRG5 BRG13 TRISB5 TXEN Bit 4 SCKP INTE TXIE TXIF CREN BRG4 BRG12 TRISB4 SYNC SENDB BRGH TRMT TX9D Bit 3 BRG16 RABIE SSPIE SSPIF ADDEN BRG3 BRG11 Bit 2 -- T0IF CCP1IE CCP1IF FERR BRG2 BRG10 Bit 1 WUE INTF TMR2IE TMR2IF OERR BRG1 BRG9 Bit 0 ABDEN RABIF TMR1IE TMR1IF RX9D BRG0 BRG8 Value on POR, BOR 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010
Bit 7 ABDOVF GIE -- -- SPEN BRG7 BRG15 TRISB7 CSRC
EUSART Receive Data Register
EUSART Transmit Data Register
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for Synchronous Slave Transmission.
(c) 2007 Microchip Technology Inc.
DS41262D-page 173
PIC16F631/677/685/687/689/690
12.4.2.3 EUSART Synchronous Slave Reception 12.4.2.4
1. 2.
Synchronous Slave Reception Set-up:
The operation of the Synchronous Master and Slave modes is identical (Section 12.4.1.5 "Synchronous Master Reception"), with the following exceptions: * Sleep * CREN bit is always set, therefore the receiver is never Idle * SREN bit, which is a "don't care" in Slave mode A character may be received while in Sleep mode by setting the CREN bit prior to entering Sleep. Once the word is received, the RSR register will transfer the data to the RCREG register. If the RCIE enable bit is set, the interrupt generated will wake the device from Sleep and execute the next instruction. If the GIE bit is also set, the program will branch to the interrupt vector.
3. 4. 5.
6.
7. 8.
Set the SYNC and SPEN bits and clear the CSRC bit. If using interrupts, ensure that the GIE and PEIE bits of the INTCON register are set and set the RCIE bit. If 9-bit reception is desired, set the RX9 bit. Set the CREN bit to enable reception. The RCIF bit will be set when reception is complete. An interrupt will be generated if the RCIE bit was set. If 9-bit mode is enabled, retrieve the Most Significant bit from the RX9D bit of the RCSTA register. Retrieve the 8 Least Significant bits from the receive FIFO by reading the RCREG register. If an overrun error occurs, clear the error by either clearing the CREN bit of the RCSTA register or by clearing the SPEN bit which resets the EUSART.
TABLE 12-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name BAUDCTL INTCON PIE1 PIR1 RCREG RCSTA SPBRG SPBRGH TRISB TXREG TXSTA Legend: Bit 7 ABDOVF GIE -- -- SPEN BRG7 BRG15 TRISB7 CSRC Bit 6 RCIDL PEIE ADIE ADIF RX9 BRG6 BRG14 TRISB6 TX9 Bit 5 -- T0IE RCIE RCIF SREN BRG5 BRG13 TRISB5 TXEN Bit 4 SCKP INTE TXIE TXIF CREN BRG4 BRG12 TRISB4 SYNC SENDB BRGH TRMT TX9D Bit 3 BRG16 RABIE SSPIE SSPIF ADDEN BRG3 BRG11 Bit 2 -- T0IF CCP1IE CCP1IF FERR BRG2 BRG10 Bit 1 WUE INTF TMR2IE TMR2IF OERR BRG1 BRG9 Bit 0 ABDEN RABIF TMR1IE TMR1IF RX9D BRG0 BRG8 Value on POR, BOR 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010 Value on all other Resets 01-0 0-00 0000 000x -000 0000 -000 0000 0000 0000 0000 000x 0000 0000 0000 0000 1111 ---0000 0000 0000 0010
EUSART Receive Data Register
EUSART Transmit Data Register
x = unknown, - = unimplemented read as `0'. Shaded cells are not used for Synchronous Slave Reception.
DS41262D-page 174
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
13.0 SSP MODULE OVERVIEW
FIGURE 13-1:
The Synchronous Serial Port (SSP) module is a serial interface used to communicate with other peripheral or microcontroller devices. These peripheral devices may be serial EEPROMs, shift registers, display drivers, A/D converters, etc. The SSP module can operate in one of two modes: * Serial Peripheral Interface (SPI) * Inter-Integrated Circuit (I2CTM) Refer to Application Note AN578, "Use of the SSP Module in the Multi-Master Environment" (DS00578).
SSPSR Reg SDI/SDA SDO bit 0 Shift Clock
SSP BLOCK DIAGRAM (SPI MODE)
Internal Data Bus Read SSPBUF Reg Write
13.1
SPI Mode
This section contains register definitions and operational characteristics of the SPI module. The SPI mode allows 8 bits of data to be synchronously transmitted and received simultaneously. To accomplish communication, typically three pins are used: * Serial Data Out (SDO) * Serial Data In (SDI) * Serial Clock (SCK) Additionally, a fourth pin may be used when in a Slave mode of operation: * Slave Select (SS) Note 1: When the SPI is in Slave mode with SS pin control enabled (SSPM<3:0> bits of the SSPCON register = 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 = 1, then the SS pin control must be enabled. 3: When the SPI is in Slave mode with SS pin control enabled (SSPM<3:0> bits of the SSPCON register = 0100), the state of the SS pin can affect the state read back from the TRISC<4> bit. The peripheral OE signal from the SSP module into PORTC controls the state that is read back from the TRISC<4> bit (see Section 17.0 "Electrical Specifications" for information on PORTC). If read-write-modify instructions, such as BSF, are performed on the TRISC register while the SS pin is high, this will cause the TRISC<7> bit to be set, thus disabling the SDO output.
Peripheral OE
SS Control Enable SS Edge Select 2 Clock Select SSPM<3:0> 4 Edge Select SCK/ SCL TRISB<6> TMR2 Output 2 Prescaler TCY 4, 16, 64
(c) 2007 Microchip Technology Inc.
DS41262D-page 175
PIC16F631/677/685/687/689/690
REGISTER 13-1:
R/W-0 SMP bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
SSPSTAT: SYNC SERIAL PORT STATUS REGISTER(1)
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
SMP: SPI Data Input Sample Phase bit SPI Master mode: 1 = Input data sampled at end of data output time 0 = Input data sampled at middle of data output time (Microwire) SPI Slave mode: SMP must be cleared when SPI is used in Slave mode I2 CTM mode: This bit must be maintained clear CKE: SPI Clock Edge Select bit SPI mode, CKP = 0: 1 = Data transmitted on rising edge of SCK (Microwire alternate) 0 = Data transmitted on falling edge of SCK SPI mode, CKP = 1: 1 = Data transmitted on falling edge of SCK (Microwire default) 0 = Data transmitted on rising edge of SCK I2 C mode: This bit must be maintained clear D/A: DATA/ADDRESS bit (I2C mode only) 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 (I2C mode only) This bit is cleared when the SSP module is disabled, or when the Start bit is detected last. SSPEN is cleared. 1 = Indicates that a Stop bit has been detected last (this bit is `0' on Reset) 0 = Stop bit was not detected last S: Start bit (I2C mode only) This bit is cleared when the SSP module is disabled, or when the Stop bit is detected last. SSPEN is cleared. 1 = Indicates that a Start bit has been detected last (this bit is `0' on Reset) 0 = Start bit was not detected last R/W: READ/WRITE bit Information (I2C mode only) 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 ACK bit. 1 = Read 0 = Write UA: Update Address bit (10-bit I2C 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 Receive (SPI and I2 C modes): 1 = Receive complete, SSPBUF is full 0 = Receive not complete, SSPBUF is empty Transmit (I2 C mode only): 1 = Transmit in progress, SSPBUF is full 0 = Transmit complete, SSPBUF is empty PIC16F687/PIC16F689/PIC16F690 only.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1:
DS41262D-page 176
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 13-2:
R/W-0 WCOL bit 7 Legend: R = Readable bit -n = Value at POR bit 7 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
SSPCON: SYNC SERIAL PORT CONTROL REGISTER(1)
R/W-0 SSPOV R/W-0 SSPEN R/W-0 CKP R/W-0 SSPM3(2) R/W-0 SSPM2(2) R/W-0 SSPM1(2) R/W-0 SSPM0(2) bit 0
WCOL: Write Collision Detect bit 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 In SPI 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. In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the SSPBUF register. 0 = No overflow In I2 CTM mode: 1 = A byte is received while the SSPBUF register is still holding the previous byte. SSPOV is a "don't care" in Transmit mode. SSPOV must be cleared in software in either mode. 0 = No overflow
bit 6
bit 5
SSPEN: Synchronous Serial Port Enable bit In SPI mode: 1 = Enables serial port and configures SCK, SDO and SDI as serial port pins 0 = Disables serial port and configures these pins as I/O port pins In I2 C mode: 1 = Enables the serial port and configures the SDA and SCL pins as serial port pins 0 = Disables serial port and configures these pins as I/O port pins In both modes, when enabled, these pins must be properly configured as input or output.
bit 4
CKP: Clock Polarity Select bit In SPI mode: 1 = Idle state for clock is a high level (Microwire default) 0 = Idle state for clock is a low level (Microwire alternate) In I2 C mode: SCK release control 1 = Enable clock 0 = Holds clock low (clock stretch). (Used to ensure data setup time.)
bit 3-0
SSPM<3:0>: Synchronous Serial Port Mode Select bits 0000 = SPI Master mode, clock = FOSC/4 0001 = SPI Master mode, clock = FOSC/16 0010 = SPI Master mode, clock = FOSC/64 0011 = SPI Master mode, clock = TMR2 output/2 0100 = SPI Slave mode, clock = SCK pin. SS pin control enabled. 0101 = SPI Slave mode, clock = SCK pin. SS pin control disabled. SS can be used as I/O pin. 0110 = I2C Slave mode, 7-bit address 0111 = I2C Slave mode, 10-bit address 1000 = Reserved 1001 = Load SSPMSK register at SSPADD SFR address(2) 1010 = Reserved 1011 = I2C Firmware Controlled Master mode (slave IDLE) 1100 = Reserved 1101 = Reserved 1110 = I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled 1111 = I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled PIC16F687/PIC16F689/PIC16F690 only. When this mode is selected, any reads or writes to the SSPADD SFR address actually accesses the SSPMSK register.
Note 1: 2:
(c) 2007 Microchip Technology Inc.
DS41262D-page 177
PIC16F631/677/685/687/689/690
13.2 Operation
When initializing the SPI, several options need to be specified. This is done by programming the appropriate control bits (SSPCON<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 SSP 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 eight bits of data have been received, that byte is moved to the SSPBUF register. Then, the Buffer Full Status bit BF of the SSPSTAT register, 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 of the SSPCON register, 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 of the SSPSTAT register 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 SSP 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 13-1 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 SSP Status register (SSPSTAT) indicates the various status conditions.
EXAMPLE 13-1:
BSF BCF BTFSS GOTO BCF MOVF MOVWF MOVF MOVWF
LOADING THE SSPBUF (SSPSR) REGISTER
;Bank 1 ; ;Has data been received(transmit complete)? ;No ;Bank 0 ;WREG reg = contents of SSPBUF ;Save in user RAM, if data is meaningful ;W reg = contents of TXDATA ;New data to xmit
LOOP
STATUS,RP0 STATUS,RP1 SSPSTAT, BF LOOP STATUS,RP0 SSPBUF, W RXDATA TXDATA, W SSPBUF
DS41262D-page 178
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
13.3 Enabling SPI I/O 13.4 Typical Connection
To enable the serial port, SSP Enable bit SSPEN of the SSPCON register 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 TRISB and TRISC registers) appropriately programmed. That is: * SDI is automatically controlled by the SPI module * SDO must have TRISC<7> bit cleared * SCK (Master mode) must have TRISB<6> bit cleared * SCK (Slave mode) must have TRISB<6> bit set * SS must have TRISC<6> bit set Any serial port function that is not desired may be overridden by programming the corresponding data direction (TRISB and TRISC) registers to the opposite value. Figure 13-2 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 13-2:
SPI MASTER/SLAVE CONNECTION
SPI Master SSPM<3:0> = 00xxb SDO Serial Input Buffer (SSPBUF) SDI
SPI Slave SSPM<3:0> = 010xb
Serial Input Buffer (SSPBUF)
Shift Register (SSPSR) MSb LSb
SDI
SDO MSb
Shift Register (SSPSR) LSb
SCK Processor 1
Serial Clock
SCK Processor 2
(c) 2007 Microchip Technology Inc.
DS41262D-page 179
PIC16F631/677/685/687/689/690
13.5 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 13-2) 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 of the SSPCON register. This then, would give waveforms for SPI communication as shown in Figure 13-3, Figure 13-5 and Figure 13-6, 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 (PIC16F685/PIC16F690 only)
This allows a maximum data rate (at 40 MHz) of 10 Mbps. Figure 13-3 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 13-3:
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
bit 7 bit 7
bit 6 bit 6
bit 5 bit 5
bit 4 bit 4
bit 3 bit 3
bit 2 bit 2
bit 1 bit 1
bit 0 bit 0
bit 7
bit 0
bit 7
bit 0
Next Q4 Cycle after Q2
DS41262D-page 180
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
13.6 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. 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.
13.7
Slave Select Synchronization
The SS pin allows a Synchronous Slave mode. The SPI must be in Slave mode with SS pin control enabled (SSPCON<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, the SDO pin is no longer driven,
FIGURE 13-4:
SS
SLAVE SYNCHRONIZATION WAVEFORM
SCK (CKP = 0 CKE = 0) SCK (CKP = 1 CKE = 0)
Write to SSPBUF
SDO
bit 7
bit 6
bit 7
bit 0
SDI (SMP = 0) Input Sample (SMP = 0) SSPIF Interrupt Flag SSPSR to SSPBUF
bit 0 bit 7 bit 7
Next Q4 Cycle after Q2
(c) 2007 Microchip Technology Inc.
DS41262D-page 181
PIC16F631/677/685/687/689/690
FIGURE 13-5:
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 Next Q4 Cycle after Q2 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)
bit 7
bit 0
FIGURE 13-6:
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)
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
bit 7
bit 0
Next Q4 Cycle after Q2
DS41262D-page 182
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
13.8 Sleep Operation 13.10 Bus Mode Compatibility
Table 13-1 shows the compatibility between the standard SPI modes and the states of the CKP and CKE control bits. 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 SSP interrupt flag bit will be set and if enabled, will wake the device from Sleep.
TABLE 13-1:
SPI BUS MODES
Control Bits State CKP 0 0 1 1 CKE 1 0 1 0
Standard SPI Mode Terminology 0, 0 0, 1 1, 0 1, 1
13.9
Effects of a Reset
A Reset disables the SSP module and terminates the current transfer.
There is also a SMP bit which controls when the data is sampled.
TABLE 13-2:
Address
REGISTERS ASSOCIATED WITH SPI OPERATION(1)
Bit 7 GIE
--
Name
Bit 6 PEIE ADIF SSPOV TRISB6 ADIE CKE
Bit 5 T0IE RCIF SSPEN TRISB5 RCIE D/A
Bit 4 INTE TXIF CKP TRISB4 TXIE P
Bit 3 RABIE SSPIF SSPM3
--
Bit 2 T0IF
Bit 1 INTF
Bit 0 RABIF
Value on POR, BOR 0000 000x -000 0000 xxxx xxxx 0000 0000 1111 ---1111 1111 -000 0000 0000 0000
Value on all other Resets 0000 000x -000 0000 uuuu uuuu 0000 0000 1111 ---1111 1111 -000 0000 0000 0000
0Bh/8Bh/ INTCON 10Bh/18Bh 0Ch 13h 14h 86h/186h 87h/187h 8Ch 94h Legend:
Note 1:
PIR1 SSPBUF SSPCON TRISB TRISC PIE1 SSPSTAT
CCP1IF TMR2IF TMR1IF SSPM2
--
Synchronous Serial Port Receive Buffer/Transmit Register WCOL TRISB7
--
SSPM1
--
SSPM0
--
TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 SSPIE S CCP1IE TMR2IE TMR1IE R/W UA BF SMP
x = unknown, u = unchanged, - = unimplemented, read as `0'. Shaded cells are not used by the SSP in SPI mode.
PIC16F687/PIC16F689/PIC16F690 only.
(c) 2007 Microchip Technology Inc.
DS41262D-page 183
PIC16F631/677/685/687/689/690
13.11 SSP I2C Operation
The SSP module in I2C mode, fully implements all slave functions, except general call support, and provides interrupts on Start and Stop bits in hardware to facilitate firmware implementations of the master functions. The SSP module implements the Standard mode specifications, as well as 7-bit and 10-bit addressing. Two pins are used for data transfer. These are the RB6/ SCK/SCL pin, which is the clock (SCL), and the RB4/ AN10/SDI/SDA pin, which is the data (SDA). The SSP module functions are enabled by setting SSP enable bit SSPEN (SSPCON<5>). The SSPCON register allows control of the I2C operation. Four mode selection bits (SSPCON<3:0>) allow one of the following I2C modes to be selected: I2C Slave mode (7-bit address) I2C Slave mode (10-bit address) I2C Slave mode (7-bit address), with Start and Stop bit interrupts enabled to support Firmware Master mode * I2C Slave mode (10-bit address), with Start and Stop bit interrupts enabled to support Firmware Master mode * I2C Start and Stop bit interrupts enabled to support Firmware Master mode; Slave is idle * * * Selection of any I2C 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 TRISB bits. Pull-up resistors must be provided externally to the SCL and SDA pins for proper operation of the I2C module.
FIGURE 13-7:
SSP BLOCK DIAGRAM (I2CTM MODE)
Internal Data Bus
Read RB6/ SCK/ SCL Shift Clock SSPSR Reg RB4/ AN10/ SDI/SDA MSb SSPBUF Reg
Write
13.12 Slave Mode
In Slave mode, the SCL and SDA pins must be configured as inputs (TRISB<6,4> are set). The SSP module will override the input state with the output data when required (slave-transmitter).
LSb Addr Match
Match Detect
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 then load the SSPBUF register with the received value currently in the SSPSR register. There are certain conditions that will cause the SSP module not to give this ACK pulse. They include (either or both): a)
SSPMSK Reg
SSPADD Reg Start and Stop bit Detect Set, Reset S, P bits (SSPSTAT Reg)
b)
The Buffer Full bit BF of the SSPSTAT register was set before the transfer was received. The overflow bit SSPOV of the SSPCON register was set before the transfer was received.
The SSP module has six registers for the I2C operation, which are listed below. SSP Control register (SSPCON) SSP Status register (SSPSTAT) Serial Receive/Transmit Buffer (SSPBUF) SSP Shift register (SSPSR) - Not directly accessible * SSP Address register (SSPADD) * SSP Mask register (SSPMSK) * * * *
In this case, the SSPSR register value is not loaded into the SSPBUF, but bit SSPIF of the PIR1 register is set. Table 13-3 shows the results of when a data transfer byte is received, given the status of bits BF and SSPOV. The shaded cells show the condition where user software did not properly clear the overflow condition. Flag bit BF 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. For high and low times of the I2C specification, as well as the requirements of the SSP module, see Section 17.0 "Electrical Specifications".
DS41262D-page 184
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
13.12.1 ADDRESSING
Once the SSP 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: a) b) c) d) The SSPSR register value is loaded into the SSPBUF register. The buffer full bit, BF is set. An ACK pulse is generated. SSP interrupt flag bit, SSPIF of the PIR1 register is set (interrupt is generated if enabled) on the falling edge of the ninth SCL pulse. The sequence of events for 10-bit address is as follows, with steps 7-9 for 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.
In 10-bit Address mode, two address bytes need to be received by the slave (Figure 13-8). 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 `1111 0 A9 A8 0', where A9 and A8 are the two MSbs of the address.
TABLE 13-3:
DATA TRANSFER RECEIVED BYTE ACTIONS
SSPSR SSPBUF Yes No No No Generate ACK Pulse Yes No No No Set bit SSPIF (SSP Interrupt occurs if enabled) Yes Yes Yes Yes
Status Bits as Data Transfer is Received BF 0 1 1 0 Note: SSPOV 0 0 1 1
Shaded cells show the conditions where the user software did not properly clear the overflow condition.
(c) 2007 Microchip Technology Inc.
DS41262D-page 185
PIC16F631/677/685/687/689/690
13.12.2 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. When the address byte overflow condition exists, then no Acknowledge (ACK) pulse is given. An overflow condition is defined as either bit BF of the SSPSTAT register is set, or bit SSPOV of the SSPCON register is set. This is an error condition due to the user's firmware. An SSP interrupt is generated for each data transfer byte. Flag bit SSPIF of the PIR1 register must be cleared in software. The SSPSTAT register is used to determine the status of the byte.
FIGURE 13-8:
I2CTM WAVEFORMS FOR RECEPTION (7-BIT ADDRESS)
R/W = 0 Receiving Address ACK Receiving Data D7 D6 D5 D4 D3 D2 D1 D0 8 9 1 2 3 4 5 6 7 8 9 ACK Receiving Data ACK D7 D6 D5 D4 D3 D2 D1 D0 1 2 3 4 5 6 7 8 9 P
SDA
A7 A6 A5 A4 A3 A2 A1 1 2 3 4 5 6 7
SCL
S
SSPIF (PIR1<3>)
Cleared in software
Bus Master terminates transfer
BF (SSPSTAT<0>)
SSPBUF register is read
SSPOV (SSPCON<6>) Bit SSPOV is set because the SSPBUF register is still full. ACK is not sent.
DS41262D-page 186
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
13.12.3 SSP MASK REGISTER
An SSP Mask (SSPMSK) register is available in I2C Slave mode as a mask for the value held in the SSPSR register during an address comparison operation. A zero (`0') bit in the SSPMSK register has the effect of making the corresponding bit in the SSPSR register a `don't care'. This register is reset to all `1's upon any Reset condition and, therefore, has no effect on standard SSP operation until written with a mask value. This register must be initiated prior to setting SSPM<3:0> bits to select the I2C Slave mode (7-bit or 10-bit address). This register can only be accessed when the appropriate mode is selected by bits (SSPM<3:0> of SSPCON). The SSP Mask register is active during: * 7-bit Address mode: address compare of A<7:1>. * 10-bit Address mode: address compare of A<7:0> only. The SSP mask has no effect during the reception of the first (high) byte of the address.
REGISTER 13-3:
R/W-1 MSK7 bit 7 Legend: R = Readable bit -n = Value at POR bit 7-1
SSPMSK: SSP MASK REGISTER(1)
R/W-1 MSK6 R/W-1 MSK5 R/W-1 MSK4 R/W-1 MSK3 R/W-1 MSK2 R/W-1 MSK1 R/W-1 MSK0(2) bit 0
W = Writable bit `1' = Bit is set
U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
MSK<7:1>: Mask bits 1 = The received address bit n is compared to SSPADD to detect I2C address match 0 = The received address bit n is not used to detect I2C address match MSK<0>: Mask bit for I2C Slave mode, 10-bit Address(2) I2C Slave mode, 10-bit Address (SSPM<3:0> = 0111): 1 = The received address bit 0 is compared to SSPADD<0> to detect I2C address match 0 = The received address bit 0 is not used to detect I2C address match
bit 0
Note 1: When SSPCON bits SSPM<3:0> = 1001, any reads or writes to the SSPADD SFR address are accessed through the SSPMSK register. The SSPEN bit of the SSPCON register should be zero when accessing the SSPMSK register. 2: In all other SSP modes, this bit has no effect.
(c) 2007 Microchip Technology Inc.
DS41262D-page 187
FIGURE 13-9:
DS41262D-page 188
Clock is held low until update of SSPADD has taken place Receive Data Byte ACK D7 D6 D5 D4 D3 D2 D1 D0 Receive Data Byte ACK D7 D6 D5 D4 D3 D2 D1 D0 Receive Second Byte of Address ACK A7 A6 A5 A4 A3 A2 A1 A0 1 4 6 1 5 6 7 4 5 6 7 1 2 3 4 5 7 8 2 3 2 3 8 9 9 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
Clock is held low until update of SSPADD has taken place
SDA
Receive First Byte of Address R/W = 0 ACK 1 1 1 1 0 A9 A8 0
SCL
S
1
2
3
4
5
6
7
8
9
SSPIF
(PIR1<3>)
Cleared in software
BF (SSPSTAT<0>)
SSPBUF is written with contents of SSPSR
SSPOV (SSPCON<6>)
PIC16F631/677/685/687/689/690
UA (SSPSTAT<1>) Cleared by hardware when SSPADD is updated with high byte of address
I2CTM SLAVE MODE TIMING (RECEPTION, 10-BIT ADDRESS)
UA is set indicating that the SSPADD needs to be updated
(c) 2007 Microchip Technology Inc.
CKP
(CKP does not reset to `0' when SEN = 0)
PIC16F631/677/685/687/689/690
13.12.4 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 RB6/SCK/SCL is held low. The transmit data must be loaded into the SSPBUF register, which also loads the SSPSR register. Then, pin RB6/SCK/SCL should be enabled by setting bit CKP (SSPCON<4>). The master must monitor the SCL pin prior to asserting another clock pulse. The slave devices may be holding off the master by stretching the clock. 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 13-10). An SSP interrupt is generated for each data transfer byte. Flag bit SSPIF must be cleared in software, and the SSPSTAT register is used to determine the status of the byte. Flag bit SSPIF is set on the falling edge of the ninth clock pulse. As a slave-transmitter, the ACK pulse from the master receiver is latched on the rising edge of the ninth SCL input pulse. If the SDA line was high (not ACK), then the data transfer is complete. When the ACK is latched by the slave, the slave logic is reset (resets SSPSTAT register) and the slave then monitors for another occurrence of the Start bit. If the SDA line was low (ACK), the transmit data must be loaded into the SSPBUF register, which also loads the SSPSR register. Then pin RB6/SCK/SCL should be enabled by setting bit CKP.
FIGURE 13-10:
I2CTM WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)
Receiving Address R/W = 1 A1 ACK D7 D6 D5 D4 Transmitting Data D3 D2 D1 D0 ACK
SDA
A7
A6
A5
A4
A3
A2
SCL
S
1 2 Data in sampled
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
SSPIF (PIR1<3>) BF (SSPSTAT<0>)
Cleared in software
SSPBUF is written in software CKP (SSPCON<4>)
From SSP Interrupt Service Routine
Set bit after writing to SSPBUF (the SSPBUF must be written to before the CKP bit can be set)
(c) 2007 Microchip Technology Inc.
DS41262D-page 189
FIGURE 13-11:
DS41262D-page 190
1 4 6 1 4 5 6 7 8 5 6 7 1 2 3 4 5 7 8 2 3 2 3 8 9 9 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
SDA
Clock is held low until Clock is held low until update of SSPADD has update of SSPADD has taken place taken place R/W = 0 Receive Second Byte of Address Receive First Byte of Address Receive Data Byte Receive Data Byte ACK ACK ACK ACK A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 1 1 1 1 0 A9 A8 0 D7 D6 D5 D4 D3 D2 D1 D0
SCL
S
1
2
3
4
5
6
7
8
9
SSPIF
(PIR1<3>)
Cleared in software
BF (SSPSTAT<0>)
SSPBUF is written with contents of SSPSR
SSPOV (SSPCON<6>)
PIC16F631/677/685/687/689/690
UA (SSPSTAT<1>)
UA is set indicating that the SSPADD needs to be updated
I2CTM SLAVE MODE TIMING (TRANSMISSION, 10-BIT ADDRESS)
(c) 2007 Microchip Technology Inc.
CKP
(CKP does not reset to `0' when SEN = 0)
PIC16F631/677/685/687/689/690
13.13 Master Mode
Master mode of operation is supported in firmware using 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 SSP module is disabled. The Stop (P) and Start (S) bits will toggle based on the Start and Stop conditions. Control of the I2C bus may be taken when the P bit is set or the bus is idle and both the S and P bits are clear. In Master mode, the SCL and SDA lines are manipulated by clearing the corresponding TRISB<6,4> bit(s). The output level is always low, irrespective of the value(s) in PORTB<6,4>. So when transmitting data, a `1' data bit must have the TRISB<4> bit set (input) and a `0' data bit must have the TRISB<4> bit cleared (output). The same scenario is true for the SCL line with the TRISB<6> bit. Pull-up resistors must be provided externally to the SCL and SDA pins for proper operation of the I2C module. The following events will cause the SSP Interrupt Flag bit, SSPIF, to be set (SSP Interrupt will occur if enabled): * Start condition * Stop condition * Data transfer byte transmitted/received Master mode of operation can be done with either the Slave mode idle (SSPM<3:0> = 1011), or with the Slave active. When both Master and Slave modes are enabled, the software needs to differentiate the source(s) of the interrupt.
13.14 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 SSP module is disabled. The Stop (P) and Start (S) bits will toggle based on the Start and Stop conditions. Control of the I2C bus may be taken when bit P (SSPSTAT<4>) is set, or the bus is idle and 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 to see if the signal level is the expected output level. This check only needs to be done when a high level is output. If a high level is expected and a low level is present, the device needs to release the SDA and SCL lines (set TRISB<6,4>). There are two stages where this arbitration can be lost, these are: * Address Transfer * Data Transfer When the slave logic is enabled, the slave continues to receive. If arbitration was lost during the address transfer stage, communication to the device may be in progress. If addressed, an ACK pulse will be generated. If arbitration was lost during the data transfer stage, the device will need to re-transfer the data at a later time.
13.14.1
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 deasserted SCL. This ensures that a write to the CKP bit will not violate the minimum high time requirement for SCL (see Figure 13-12).
(c) 2007 Microchip Technology Inc.
DS41262D-page 191
PIC16F631/677/685/687/689/690
FIGURE 13-12: 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 deasserts clock
WR SSPCON
TABLE 13-4:
Addr Name
REGISTERS ASSOCIATED WITH I2CTM OPERATION(1)
Bit 7 GIE -- Bit 6 PEIE ADIF Bit 5 T0IE RCIF Bit 4 INTE TXIF Bit 3 RABIE SSPIF Bit 2 T0IF CCP1IF Bit 1 INTF TMR2IF Bit 0 RABIF TMR1IF Value on POR, BOR 0000 000x -000 0000 xxxx xxxx SSPM2 -- MSK2 R/W CCP1IE SSPM1 -- MSK1 UA TMR2IF SSPM0 -- MSK0 BF TMR1IF 0000 0000 1111 ---1111 1111 0000 0000 -000 0000 Value on all other Resets 0000 000x -000 0000 uuuu uuuu 0000 0000 1111 ---1111 1111 0000 0000 -000 0000
0Bh/8Bh/ INTCON 10Bh/18Bh 0Ch 13h 14h 86h 93h 94h 8Ch Legend: Note 1: 2: 3: PIR1 SSPBUF SSPCON TRISB SSPMSK(2) SSPSTAT PIE1
Synchronous Serial Port Receive Buffer/Transmit Register WCOL TRISB7 MSK7 SMP(3) -- SSPOV TRISB6 MSK6 CKE(3) ADIE SSPEN TRISB5 MSK5 D/A RCIE CKP TRISB4 MSK4 P TXIE SSPM3 -- MSK3 S SSPIE
- = Unimplemented locations, read as `0', u = unchanged, x = unknown. Shaded cells are not used by the SSP module. PIC16F687/PIC16F689/PIC16F690 only. SSPMSK register (Register 13-3) can be accessed by reading or writing to SSPADD register with bits SSPM<3:0> = 1001. See Registers 13-2 and 13-3 for more details. Maintain these bits clear.
DS41262D-page 192
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
14.0 SPECIAL FEATURES OF THE CPU
The PIC16F631/677/685/687/689/690 have a host of features intended to maximize system reliability, minimize cost through elimination of external components, provide power saving features and offer code protection. These features are: * Reset - Power-on Reset (POR) - Power-up Timer (PWRT) - Oscillator Start-up Timer (OST) - Brown-out Reset (BOR) * Interrupts * Watchdog Timer (WDT) * Oscillator selection * Sleep * Code protection * ID Locations * In-Circuit Serial Programming The PIC16F631/677/685/687/689/690 have 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 of 64 ms (nominal) on power-up only, designed to keep the part in Reset while the power supply stabilizes. There is also circuitry to reset the device if a brown-out occurs, which can use the Powerup Timer to provide at least a 64 ms Reset. With these three functions-on-chip, most applications need no external Reset circuitry. The 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 * An interrupt Several oscillator options are also made available to allow the part to fit the application. The INTOSC option saves system cost while the LP crystal option saves power. A set of Configuration bits are used to select various options (see Register 14-2).
(c) 2007 Microchip Technology Inc.
DS41262D-page 193
PIC16F631/677/685/687/689/690
14.1 Configuration Bits
The Configuration bits can be programmed (read as `0'), or left unprogrammed (read as `1') to select various device configurations as shown in Register 14-2. These bits are mapped in program memory location 2007h. Note: Address 2007h is beyond the user program memory space. It belongs to the special configuration memory space (2000h3FFFh), which can be accessed only during programming. See "PIC12F6XX/16F6XX Memory Programming Specification" (DS41204) for more information.
DS41262D-page 194
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 14-1:
Reserved bit 13
CONFIG: CONFIGURATION WORD REGISTER
Reserved FCMEN IESO BOREN1(1) BOREN0(1) CPD(2 bit 7
CP(3) bit 6
MCLRE(4)
PWRTE
WDTE
FOSC2
FOSC1
FOSC0 bit 0
Legend: R = Readable bit -n = Value at POR W = Writable bit `1' = Bit is set P = Programmable' `0' = Bit is cleared U = Unimplemented bit, read as `0' x = Bit is unknown
bit 13-12 bit 11
Reserved: Reserved bits. Do Not Use. FCMEN: Fail-Safe Clock Monitor Enabled bit 1 = Fail-Safe Clock Monitor is enabled 0 = Fail-Safe Clock Monitor is disabled IESO: Internal External Switchover bit 1 = Internal External Switchover mode is enabled 0 = Internal External Switchover mode is disabled BOREN<1:0>: Brown-out Reset Selection bits(1) 11 = BOR enabled 10 = BOR enabled during operation and disabled in Sleep 01 = BOR controlled by SBOREN bit of the PCON register 00 = BOR disabled CPD: Data Code Protection bit(2) 1 = Data memory code protection is disabled 0 = Data memory code protection is enabled CP: Code Protection bit(2) 1 = Program memory code protection is disabled 0 = Program memory code protection is enabled MCLRE: MCLR Pin Function Select bit(3) 1 = MCLR pin function is MCLR 0 = MCLR pin function is digital input, MCLR internally tied to VDD PWRTE: Power-up Timer Enable bit 1 = PWRT disabled 0 = PWRT enabled WDTE: Watchdog Timer Enable bit 1 = WDT enabled 0 = WDT disabled FOSC<2:0>: Oscillator Selection bits 111 = RC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN 110 = RCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN 101 = INTOSC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN 100 = INTOSCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN 011 = EC: I/O function on RA4/OSC2/CLKOUT pin, CLKIN on RA5/OSC1/CLKIN 010 = HS oscillator: High-speed crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN 001 = XT oscillator: Crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN 000 = LP oscillator: Low-power crystal on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
bit 10
bit 9-8
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
Note
1: 2: 3: 4:
Enabling Brown-out Reset does not automatically enable Power-up Timer. The entire data EEPROM will be erased when the code protection is turned off. The entire program memory will be erased when the code protection is turned off. When MCLR is asserted in INTOSC or RC mode, the internal clock oscillator is disabled.
(c) 2007 Microchip Technology Inc.
DS41262D-page 195
PIC16F631/677/685/687/689/690
14.2 Reset
The PIC16F631/677/685/687/689/690 differentiates between various kinds of Reset: a) b) c) d) e) f) Power-on Reset (POR) WDT Reset during normal operation WDT Reset during Sleep MCLR Reset during normal operation MCLR Reset during Sleep Brown-out Reset (BOR) They are not affected by a WDT Wake-up since this is viewed as the resumption of normal operation. TO and PD bits are set or cleared differently in different Reset situations, as indicated in Table 14-2. These bits are used in software to determine the nature of the Reset. See Table 14-4 for a full description of Reset states of all registers. A simplified block diagram of the On-Chip Reset Circuit is shown in Figure 14-1. The MCLR Reset path has a noise filter to detect and ignore small pulses. See Section 17.0 "Electrical Specifications" for pulse-width specifications.
Some registers are not affected in any Reset condition; their status is unknown on POR and unchanged in any other Reset. Most other registers are reset to a "Reset state" on: * * * * * Power-on Reset MCLR Reset MCLR Reset during Sleep WDT Reset Brown-out Reset (BOR)
FIGURE 14-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External Reset
MCLR/VPP pin Sleep WDT Module VDD Rise Detect VDD Brown-out(1) Reset Power-on Reset BOREN SBOREN WDT Time-out Reset
S
OST/PWRT OST 10-bit Ripple Counter OSC1/ CLKI pin PWRT LFINTOSC 11-bit Ripple Counter R Q Chip_Reset
Enable PWRT Enable OST
Note
1:
Refer to the Configuration Word register (Register 14-1).
DS41262D-page 196
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
14.2.1 POWER-ON RESET (POR) FIGURE 14-2:
The on-chip POR circuit holds the chip in Reset until VDD has reached a high enough level for proper operation. A maximum rise time for VDD is required. See Section 17.0 "Electrical Specifications" for details. If the BOR is enabled, the maximum rise time specification does not apply. The BOR circuitry will keep the device in Reset until VDD reaches VBOR (see Section 14.2.4 "Brown-out Reset (BOR)"). Note: The POR circuit does not produce an internal Reset when VDD declines. To re-enable the POR, VDD must reach Vss for a minimum of 100 s.
RECOMMENDED MCLR CIRCUIT
PIC16F685
VDD R1 1 k (or greater) MCLR C1 0.1 F (optional, not critical)
When the device starts normal operation (exits the Reset condition), device operating parameters (i.e., 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. For additional information, refer to Application Note AN607, "Power-up Trouble Shooting" (DS00607).
14.2.3
POWER-UP TIMER (PWRT)
14.2.2
MCLR
PIC16F631/677/685/687/689/690 has a noise filter in the MCLR Reset path. The filter will detect and ignore small pulses. It should be noted that a WDT Reset does not drive MCLR pin low. The behavior of the ESD protection on the MCLR pin has been altered from early devices of this family. Voltages applied to the pin that exceed its specification can result in both MCLR Resets and excessive current beyond the device specification during the ESD event. For this reason, Microchip recommends that the MCLR pin no longer be tied directly to VDD. The use of an RC network, as shown in Figure 14-2, is suggested. An internal MCLR option is enabled by clearing the MCLRE bit in the Configuration Word register. When MCLRE = 0, the Reset signal to the chip is generated internally. When the MCLRE = 1, the RA3/MCLR pin becomes an external Reset input. In this mode, the RA3/MCLR pin has a weak pull-up to VDD.
The Power-up Timer provides a fixed 64 ms (nominal) time-out on power-up only, from POR or Brown-out Reset. The Power-up Timer operates from the 31 kHz LFINTOSC oscillator. For more information, see Section 3.5 "Internal Clock Modes". The chip is kept in Reset as long as PWRT is active. The PWRT delay allows the VDD to rise to an acceptable level. A Configuration bit, PWRTE, can disable (if set) or enable (if cleared or programmed) the Power-up Timer. The Power-up Timer should be enabled when Brown-out Reset is enabled, although it is not required. The Power-up Timer delay will vary from chip-to-chip and vary due to: * VDD variation * Temperature variation * Process variation See DC parameters for details (Section 17.0 "Electrical Specifications").
(c) 2007 Microchip Technology Inc.
DS41262D-page 197
PIC16F631/677/685/687/689/690
14.2.4 BROWN-OUT RESET (BOR)
The BOREN0 and BOREN1 bits in the Configuration Word register select one of four BOR modes. Two modes have been added to allow software or hardware control of the BOR enable. When BOREN<1:0> = 01, the SBOREN bit (PCON<4>) enables/disables the BOR allowing it to be controlled in software. By selecting BOREN<1:0>, the BOR is automatically disabled in Sleep to conserve power and enabled on wake-up. In this mode, the SBOREN bit is disabled. See Register 14-2 for the Configuration Word definition. If VDD falls below VBOR for greater than parameter (TBOR) (see Section 17.0 "Electrical Specifications"), the Brown-out situation will reset the device. This will occur regardless of VDD slew rate. A Reset is not insured to occur if VDD falls below VBOR for less than parameter (TBOR). On any Reset (Power-on, Brown-out Reset, Watchdog Timer, etc.), the chip will remain in Reset until VDD rises above VBOR (see Figure 14-3). The Power-up Timer will now be invoked, if enabled and will keep the chip in Reset an additional 64 ms. Note: The Power-up Timer is enabled by the PWRTE bit in the Configuration Word register.
If VDD drops below VBOR while the Power-up Timer is running, the chip will go back into a Brown-out Reset and the Power-up Timer will be re-initialized. Once VDD rises above VBOR, the Power-up Timer will execute a 64 ms Reset.
FIGURE 14-3:
VDD
BROWN-OUT SITUATIONS
VBOR
Internal Reset VDD
64 ms(1)
VBOR < 64 ms
Internal Reset
64 ms(1)
VDD
VBOR
Internal Reset Note 1: 64 ms delay only if PWRTE bit is programmed to `0'.
64 ms(1)
DS41262D-page 198
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
14.2.5 TIME-OUT SEQUENCE 14.2.6
On power-up, the time-out sequence is as follows: first, PWRT time-out is invoked after POR has expired, then OST is activated after the PWRT time-out has expired. The total time-out will vary based on oscillator configuration and PWRTE bit status. For example, in EC mode with PWRTE bit erased (PWRT disabled), there will be no time-out at all. Figures 14-4, 14-5 and 14-6 depict time-out sequences. The device can execute code from the INTOSC while OST is active by enabling Two-Speed Start-up or Fail-Safe Monitor (see Section 3.7.2 "Two-speed Start-up Sequence" and Section 3.8 "Fail-Safe Clock Monitor"). Since the time-outs occur from the POR pulse, if MCLR is kept low long enough, the time-outs will expire. Then, bringing MCLR high will begin execution immediately (see Figure 14-5). This is useful for testing purposes or to synchronize more than one PIC16F631/677/685/ 687/689/690 device operating in parallel. Table 14-5 shows the Reset conditions for some special registers, while Table 14-4 shows the Reset conditions for all the registers.
POWER CONTROL (PCON) REGISTER
The Power Control register PCON (address 8Eh) has two Status bits to indicate what type of Reset that last occurred. Bit 0 is BOR (Brown-out Reset). BOR is unknown on Power-on Reset. It must then be set by the user and checked on subsequent Resets to see if BOR = 0, indicating that a Brown-out has occurred. The BOR Status bit is a "don't care" and is not necessarily predictable if the brown-out circuit is disabled (BOREN<1:0> = 00 in the Configuration Word register). Bit 1 is POR (Power-on Reset). It is a `0' on Power-on Reset and unaffected otherwise. The user must write a `1' to this bit following a Power-on Reset. On a subsequent Reset, if POR is `0', it will indicate that a Power-on Reset has occurred (i.e., VDD may have gone too low). For more information, see Section 4.2.4 "Ultra LowPower Wake-up" and Section 14.2.4 "Brown-out Reset (BOR)".
TABLE 14-1:
TIME-OUT IN VARIOUS SITUATIONS
Power-up Brown-out Reset PWRTE = 0 TPWRT + 1024 * TOSC TPWRT TPWRT PWRTE = 1 1024 * TOSC -- -- Wake-up from Sleep 1024 * TOSC -- --
Oscillator Configuration PWRTE = 0 XT, HS, LP LP, T1OSCIN = 1 RC, EC, INTOSC TPWRT + 1024 * TOSC TPWRT TPWRT PWRTE = 1 1024 * TOSC -- --
TABLE 14-2:
POR 0 u u u u u x 0 u u u u
STATUS/PCON BITS AND THEIR SIGNIFICANCE
TO 1 1 0 0 u 1 PD 1 1 u 0 u 0 Power-on Reset Brown-out Reset WDT Reset WDT Wake-up MCLR Reset during normal operation MCLR Reset during Sleep Condition
BOR
Legend: u = unchanged, x = unknown
TABLE 14-3:
Name
SUMMARY OF REGISTERS ASSOCIATED WITH BROWN-OUT
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR --01 --qq 0001 1xxx Value on all other Resets --0u --uu 000q quuu
PCON STATUS Legend: Note 1:
-- IRP
-- RP1
ULPWUE RPO
SBOREN TO
-- PD
-- Z
POR DC
BOR C
u = unchanged, x = unknown, - = unimplemented bit, reads as `0', q = value depends on condition. Shaded cells are not used by BOR. Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
(c) 2007 Microchip Technology Inc.
DS41262D-page 199
PIC16F631/677/685/687/689/690
FIGURE 14-4: TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 1
VDD MCLR Internal POR TPWRT PWRT Time-out
TOST
OST Time-out
Internal Reset
FIGURE 14-5:
TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 2
VDD MCLR Internal POR TPWRT PWRT Time-out
TOST
OST Time-out
Internal Reset
FIGURE 14-6:
VDD MCLR Internal POR
TIME-OUT SEQUENCE ON POWER-UP (MCLR WITH VDD)
TPWRT PWRT Time-out
TOST
OST Time-out
Internal Reset
DS41262D-page 200
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 14-4: INITIALIZATION CONDITION FOR REGISTER
MCLR Reset WDT Reset Brown-out Reset(1) uuuu uuuu xxxx xxxx uuuu uuuu 0000 0000 000q quuu(4) uuuu uuuu --uu uuuu uuuu ---uuuu uuuu ---0 0000 0000 000u -000 0000 0000 ---uuuu uuuu uuuu uuuu uuuu uuuu 0000 0000 -000 0000 uuuu uuuu 0000 0000 uuuu uuuu uuuu uuuu 0000 0000 0000 000x 0000 0000 0000 0000 0000 0000 0000 0000 uuuu uuuu 0000 0000 1111 1111 --11 1111 Wake-up from Sleep through Interrupt Wake-up from Sleep through WDT Time-out uuuu uuuu uuuu uuuu uuuu uuuu PC + 1(3) uuuq quuu(4) uuuu uuuu --uu uuuu uuuu ---uuuu uuuu ---u uuuu uuuu uuuu(2) -uuu uuuu(2) uuuu ----(2) uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu -uuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu --uu uuuu
Register
Address
Power-on Reset
W INDF TMR0 PCL STATUS FSR PORTA PORTB PORTC PCLATH INTCON PIR1 PIR2 TMR1L TMR1H T1CON TMR2 T2CON SSPBUF SSPCON CCPR1L CCPR1H CCP1CON RCSTA TXREG RCREG PWM1CON ECCPAS ADRESH ADCON0 OPTION_REG TRISA Legend: Note 1: 2: 3: 4: 5: 6:
-- 00h/80h/ 100h/180h 01h/101h 02h/82h/ 102h/182h 03h/83h/ 103h/183h 04h/84h/ 104h184h 05h/105h 06h/106h 07h/107h 0Ah/8Ah/ 10Ah/18Ah 0Bh/8Bh/ 10Bh/18Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Ch 1Dh 1Eh 1Fh 81h/181h 85h/185h
xxxx xxxx xxxx xxxx xxxx xxxx 0000 0000 0001 1xxx xxxx xxxx --xx xxxx xxxx ---xxxx xxxx ---0 0000 0000 000x -000 0000 0000 ---xxxx xxxx xxxx xxxx 0000 0000 0000 0000 -000 0000 xxxx xxxx 0000 0000 xxxx xxxx xxxx xxxx 0000 0000 0000 000x 0000 0000 0000 0000 0000 0000 0000 0000 xxxx xxxx 0000 0000 1111 1111 --11 1111
u = unchanged, x = unknown, -- = unimplemented bit, reads as `0', q = value depends on condition. If VDD goes too low, Power-on Reset will be activated and registers will be affected differently. One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up). When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h). See Table 14-5 for Reset value for specific condition. If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u. Accessible only when SSPM<3:0> = 1001.
(c) 2007 Microchip Technology Inc.
DS41262D-page 201
PIC16F631/677/685/687/689/690
TABLE 14-4: INITIALIZATION CONDITION FOR REGISTER (CONTINUED)
MCLR Reset WDT Reset (Continued) Brown-out Reset(1) 1111 ---1111 1111 -000 0000 0000 -----0u --uq1, 5) -110 q000 ---u uuuu 1111 1111 1111 1111 1111 1111 1111 1111 --11 -111 --00 0000 ---0 1000 0000 0010 0000 0000 0000 0000 01-0 0-00 uuuu uuuu -000 ---0000 0000 0000 0000 --00 0000 ---- 0000 1111 ---0000 ---0000 0000 0000 -000 0000 -000 00-- --10 1111 1111 ---- 1111 u--- q000 ---- ------0 0001 0000 00-Wake-up from Sleep through Interrupt Wake-up from Sleep through WDT Time-out uuuu ---uuuu uuuu -uuu uuuu uuuu uuuu --uu --uu -uuu uuuu ---u uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu uuuu --uu uuuu ---u uuuu uuuu uuuu uuuu uuuu uuuu uuuu uu-u u-uu uuuu uuuu -uuu ---uuuu uuuu uuuu uuuu --uu uuuu ---- uuuu uuuu ---uuuu ---uuuu uuuu uuuu -uuu uuuu -uuu uu-- --uu uuuu uuuu ---- uuuu ---- uuuu ---- ------u uuuu uuuu uu--
Register
Address
Power-on Reset
TRISB TRISC PIE1 PIE2 PCON OSCCON OSCTUNE PR2 SSPADD SSPMSK(6) SSPSTAT WPUA IOCA WDTCON TXSTA SPBRG SPBRGH BAUDCTL ADRESL ADCON1 EEDAT EEADR EEDATH EEADRH WPUB IOCB VRCON CM1CON0 CM2CON0 CM2CON1 ANSEL ANSELH EECON1 EECON2 PSTRCON SRCON Legend: Note 1: 2: 3: 4: 5: 6:
86h/186h 87h/187h 8Ch 8Dh 8Eh 8Fh 90h 92h 93h 93h 94h 95h 96h 97h 98h 99h 9Ah 9Bh 9Eh 9Fh 10Ch 10Dh 10Eh 10Fh 115h 116h 118h 119h 11Ah 11Bh 11Eh 11Fh 18Ch 18Dh 19Dh 19EH
1111 ---1111 1111 -000 0000 0000 -----01 --0x -110 q000 ---0 0000 1111 1111 0000 0000 ---- ---0000 0000 --11 -111 --00 0000 ---0 1000 0000 0010 0000 0000 0000 0000 01-0 0-00 xxxx xxxx -000 ---0000 0000 0000 0000 --00 0000 ---- 0000 1111 ---0000 ---0000 0000 0000 -000 0000 -000 00-- --00 1111 1111 ---- 1111 x--- x000 ---- ------0 0001 0000 00--
u = unchanged, x = unknown, -- = unimplemented bit, reads as `0', q = value depends on condition. If VDD goes too low, Power-on Reset will be activated and registers will be affected differently. One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up). When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h). See Table 14-5 for Reset value for specific condition. If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u. Accessible only when SSPM<3:0> = 1001.
DS41262D-page 202
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 14-5: INITIALIZATION CONDITION FOR SPECIAL REGISTERS
Condition Power-on Reset MCLR Reset during normal operation MCLR Reset during Sleep WDT Reset WDT Wake-up Brown-out Reset Interrupt Wake-up from Sleep Program Counter 000h 000h 000h 000h PC + 1 000h PC + 1
(1)
Status Register 0001 1xxx 000u uuuu 0001 0uuu 0000 uuuu uuu0 0uuu 0001 1uuu uuu1 0uuu
PCON Register --01 --0x --0u --uu --0u --uu --0u --uu --uu --uu --01 --u0 --uu --uu
Legend: u = unchanged, x = unknown, -- = unimplemented bit, reads as `0'. Note 1: When the wake-up is due to an interrupt and Global Interrupt Enable bit, GIE, is set, the PC is loaded with the interrupt vector (0004h) after execution of PC + 1.
(c) 2007 Microchip Technology Inc.
DS41262D-page 203
PIC16F631/677/685/687/689/690
14.3 Interrupts
When an interrupt is serviced: * The GIE is cleared to disable any further interrupt. * The return address is pushed onto the stack. * The PC is loaded with 0004h. For external interrupt events, such as the INT pin, PORTA/PORTB change interrupts, the interrupt latency will be three or four instruction cycles. The exact latency depends upon when the interrupt event occurs (see Figure 14-8). The latency is the same for one or two-cycle instructions. Once in the Interrupt Service Routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. The interrupt flag bit(s) must be cleared in software before re-enabling interrupts to avoid multiple interrupt requests. Note 1: Individual interrupt flag bits are set, regardless of the status of their corresponding mask bit or the GIE bit. 2: When an instruction that clears the GIE bit is executed, any interrupts that were pending for execution in the next cycle are ignored. The interrupts, which were ignored, are still pending to be serviced when the GIE bit is set again. For additional information on Timer1, Timer2, comparators, A/D, data EEPROM, EUSART, SSP or Enhanced CCP modules, refer to the respective peripheral section. The PIC16F631/677/685/687/689/690 have multiple sources of interrupt: * * * * * * * * * * * External Interrupt RA2/INT TMR0 Overflow Interrupt PORTA/PORTB Change Interrupts 2 Comparator Interrupts A/D Interrupt (except PIC16F631) Timer1 Overflow Interrupt Timer2 Match Interrupt (PIC16F685/PIC16F690 only) EEPROM Data Write Interrupt Fail-Safe Clock Monitor Interrupt Enhanced CCP Interrupt (PIC16F685/PIC16F690 only) EUSART Receive and Transmit interrupts (PIC16F687/PIC16F689/PIC16F690 only)
The Interrupt Control register (INTCON) and Peripheral Interrupt Request Register 1 (PIR1) record individual interrupt requests in flag bits. The INTCON register also has individual and global interrupt enable bits. A Global Interrupt Enable bit, GIE (INTCON<7>), enables (if set) all unmasked interrupts, or disables (if cleared) all interrupts. Individual interrupts can be disabled through their corresponding enable bits in the INTCON, PIE1 and PIE2 registers, respectively. GIE is cleared on Reset. The Return from Interrupt instruction, RETFIE, exits the interrupt routine, as well as sets the GIE bit, which re-enables unmasked interrupts. The following interrupt flags are contained in the INTCON register: * INT Pin Interrupt * PORTA/PORTB Change Interrupts * TMR0 Overflow Interrupt The peripheral interrupt flags are contained in the PIR1 and PIR2 registers. The corresponding interrupt enable bits are contained in PIE1 and PIE2 registers. The following interrupt flags are contained in the PIR1 register: * * * * * * * A/D Interrupt EUSART Receive and Transmit Interrupts Timer1 Overflow Interrupt Synchronous Serial Port (SSP) Interrupt Enhanced CCP1 Interrupt Timer1 Overflow Interrupt Timer2 Match Interrupt
14.3.1
RA2/INT INTERRUPT
External interrupt on RA2/INT pin is edge-triggered; either rising if the INTEDG bit (OPTION_REG<6>) is set, or falling, if the INTEDG bit is clear. When a valid edge appears on the RA2/INT pin, the INTF bit (INTCON<1>) is set. This interrupt can be disabled by clearing the INTE control bit (INTCON<4>). The INTF bit must be cleared in software in the Interrupt Service Routine before re-enabling this interrupt. The RA2/INT interrupt can wake-up the processor from Sleep, if the INTE bit was set prior to going into Sleep. The status of the GIE bit decides whether or not the processor branches to the interrupt vector following wake-up (0004h). See Section 14.6 "Power-Down Mode (Sleep)" for details on Sleep and Figure 14-10 for timing of wake-up from Sleep through RA2/INT interrupt. Note: The ANSEL and CM2CON0 registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read `0'.
The following interrupt flags are contained in the PIR2 register: * Fail-Safe Clock Monitor Interrupt * 2 Comparator Interrupts * EEPROM Data Write Interrupt
DS41262D-page 204
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
14.3.2 TMR0 INTERRUPT 14.3.3 PORTA/PORTB INTERRUPT
An overflow (FFh 00h) in the TMR0 register will set the T0IF (INTCON<2>) bit. The interrupt can be enabled/disabled by setting/clearing T0IE (INTCON<5>) bit. See Section 5.0 "Timer0 Module" for operation of the Timer0 module. An input change on PORTA or PORTB change sets the RABIF (INTCON<0>) bit. The interrupt can be enabled/ disabled by setting/clearing the RABIE (INTCON<3>) bit. Plus, individual pins can be configured through the IOCA or IOCB registers. Note: If a change on the I/O pin should occur when the read operation is being executed (start of the Q2 cycle), then the RABIF interrupt flag may not get set. See Section 4.2.3 "Interrupt-on-change" for more information.
FIGURE 14-7:
IOC-RA0 IOCA0 IOC-RA1 IOCA1 IOC-RA2 IOCA2 IOC-RA3 IOCA3 IOC-RA4 IOCA4 IOC-RA5 IOCA5 IOC-RB4 IOCB4 IOC-RB5 IOCB5 IOC-RB6 IOCB6 IOC-RB7 IOCB7
INTERRUPT LOGIC
SSPIF SSPIE TXIF TXIE RCIF RCIE TMR2IF TMR2IE TMR1IF TMR1IE C1IF C1IE C2IF C2IE ADIF ADIE EEIF EEIE Note 1: OSFIF OSFIE CCP1IF CCP1IE Some peripherals depend upon the system clock for operation. Since the system clock is suspended during Sleep, these peripherals will not wake the part from Sleep. See Section 14.6.1 "Wake-up from Sleep". T0IF T0IE INTF INTE RABIF RABIE PEIE GIE Wake-up (If in Sleep mode)(1) Interrupt to CPU
(c) 2007 Microchip Technology Inc.
DS41262D-page 205
PIC16F631/677/685/687/689/690
FIGURE 14-8:
Q1 OSC1 CLKOUT (3)
(4)
INT PIN INTERRUPT TIMING
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
INT pin INTF flag (INTCON<1>) GIE bit (INTCON<7>) INSTRUCTION FLOW PC Instruction Fetched Instruction Executed Note 1: 2: 3: 4: 5:
(1) (5)
(1)
Interrupt Latency (2)
PC
PC + 1 Inst (PC + 1)
PC + 1 --
0004h Inst (0004h)
0005h Inst (0005h) Inst (0004h)
Inst (PC)
Inst (PC - 1)
Inst (PC)
Dummy Cycle
Dummy Cycle
INTF flag is sampled here (every Q1). Asynchronous interrupt latency = 3-4 TCY. Synchronous latency = 3 TCY, where TCY = instruction cycle time. Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction. CLKOUT is available only in INTOSC and RC Oscillator modes. For minimum width of INT pulse, refer to AC specifications in Section 17.0 "Electrical Specifications". INTF is enabled to be set any time during the Q4-Q1 cycles.
TABLE 14-6:
Name INTCON PIE1 PIE2 PIR1 PIR2 Legend:
SUMMARY OF INTERRUPT REGISTERS
Bit 7 GIE -- Bit 6 PEIE ADIE C2IE ADIF C2IF Bit 5 T0IE RCIE C1IE RCIF C1IF Bit 4 INTE TXIE EEIE TXIF EEIF Bit 3 RABIE SSPIE -- SSPIF -- Bit 2 T0IF CCP1IE -- CCP1IF -- Bit 1 INTF TMR2IE -- TMR2IF -- Bit 0 RABIF TMR1IE -- TMR1IF -- Value on POR, BOR 0000 000x -000 0000 0000 ----000 0000 0000 ---Value on all other Resets 0000 000x -000 0000 0000 ----000 0000 0000 ----
OSFIE -- OSFIF
x = unknown, u = unchanged, -- = unimplemented read as `0', q = value depends upon condition. Shaded cells are not used by the Interrupt module.
DS41262D-page 206
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
14.4 Context Saving During Interrupts
During an interrupt, only the return PC value is saved on the stack. Typically, users may wish to save key registers during an interrupt (e.g., W and STATUS registers). This must be implemented in software. Since the upper 16 bytes of all GPR banks are common in the PIC16F631/677/685/687/689/690 (see Figures 2-2 and 2-3), temporary holding registers, W_TEMP and STATUS_TEMP, should be placed in here. These 16 locations do not require banking and therefore, make it easier to context save and restore. The same code shown in Example 14-1 can be used to: * * * * * Store the W register Store the STATUS register Execute the ISR code Restore the Status (and Bank Select Bit register) Restore the W register Note: The PIC16F631/677/685/687/689/690 normally does not require saving the PCLATH. However, if computed GOTO's are used in the ISR and the main code, the PCLATH must be saved and restored in the ISR.
EXAMPLE 14-1:
MOVWF SWAPF CLRF MOVWF
:
SAVING STATUS AND W REGISTERS IN RAM
;Copy ;Swap ;bank ;Save
W_TEMP STATUS,W STATUS STATUS_TEMP
W to TEMP register status to be saved into W 0, regardless of current bank, Clears IRP,RP1,RP0 status to bank zero STATUS_TEMP register
:(ISR) : SWAPF STATUS_TEMP,W MOVWF SWAPF SWAPF STATUS W_TEMP,F W_TEMP,W
;Insert user code here
;Swap STATUS_TEMP register into W
;(sets bank to original state)
;Move W into STATUS register ;Swap W_TEMP ;Swap W_TEMP into W
(c) 2007 Microchip Technology Inc.
DS41262D-page 207
PIC16F631/677/685/687/689/690
14.5
* * * * *
Watchdog Timer (WDT)
14.5.2
WDT CONTROL
The WDT has the following features: Operates from the LFINTOSC (31 kHz) Contains a 16-bit prescaler Shares an 8-bit prescaler with Timer0 Time-out period is from 1 ms to 268 seconds Configuration bit and software controlled
The WDTE bit is located in the Configuration Word register. When set, the WDT runs continuously. When the WDTE bit in the Configuration Word register is set, the SWDTEN bit of the WDTCON register has no effect. If WDTE is clear, then the SWDTEN bit can be used to enable and disable the WDT. Setting the bit will enable it and clearing the bit will disable it. The PSA and PS<2:0> bits of the OPTION register have the same function as in previous versions of the PIC16F631/677/685/687/689/690 Family of microcontrollers. See Section 5.0 "Timer0 Module" for more information.
WDT is cleared under certain conditions described in Table 14-7.
14.5.1
WDT OSCILLATOR
The WDT derives its time base from the 31 kHz LFINTOSC. The LTS bit of the OSCCON register does not reflect that the LFINTOSC is enabled. The value of WDTCON is `---0 1000' on all Resets. This gives a nominal time base of 17 ms. Note: When the Oscillator Start-up Timer (OST) is invoked, the WDT is held in Reset, because the WDT Ripple Counter is used by the OST to perform the oscillator delay count. When the OST count has expired, the WDT will begin counting (if enabled).
FIGURE 14-9:
WATCHDOG TIMER BLOCK DIAGRAM
From TMR0 Clock Source 0 Prescaler(1) 16-bit WDT Prescaler 1 8 PSA
PS<2:0> To TMR0 0 1 PSA
31 kHz LFINTOSC Clock
WDTPS<3:0>
WDTE from the Configuration Word Register SWDTEN from WDTCON WDT Time-out
Note
1:
This is the shared Timer0/WDT prescaler. See Section 5.4 "Prescaler" for more information.
TABLE 14-7:
WDTE = 0
WDT STATUS
Conditions WDT Cleared
CLRWDT Command Oscillator Fail Detected Exit Sleep + System Clock = T1OSC, EXTRC, INTOSC, EXTCLK Exit Sleep + System Clock = XT, HS, LP Cleared until the end of OST
DS41262D-page 208
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
REGISTER 14-2:
U-0 -- bit 7 Legend: R = Readable bit -n = Value at POR bit 7-5 bit 4-1 W = Writable bit `1' = Bit is set U = Unimplemented bit, read as `0' `0' = Bit is cleared x = Bit is unknown
WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0 -- U-0 -- R/W-0 WDTPS3 R/W-1 WDTPS2 R/W-0 WDTPS1 R/W-0 WDTPS0 R/W-0 SWDTEN(1) bit 0
Unimplemented: Read as `0' WDTPS<3:0>: Watchdog Timer Period Select bits Bit Value = Prescale Rate 0000 = 1:32 0001 = 1:64 0010 = 1:128 0011 = 1:256 0100 = 1:512 (Reset value) 0101 = 1:1024 0110 = 1:2048 0111 = 1:4096 1000 = 1:8192 1001 = 1:16384 1010 = 1:32768 1011 = 1:65536 1100 = reserved 1101 = reserved 1110 = reserved 1111 = reserved SWDTEN: Software Enable or Disable the Watchdog Timer bit(1) 1 = WDT is turned on 0 = WDT is turned off (Reset value)
bit 0
Note 1: If WDTE Configuration bit = 1, then WDT is always enabled, irrespective of this control bit. If WDTE Configuration bit = 0, then it is possible to turn WDT on/off with this control bit.
TABLE 14-8:
Name CONFIG(1) WDTCON Legend: Note 1:
SUMMARY OF WATCHDOG TIMER REGISTER
Bit 7 CPD -- Bit 6 CP -- Bit 5 MCLRE T0CS -- Bit 4 PWRTE T0SE Bit 3 WDTE PSA Bit 2 FOSC2 PS2 Bit 1 FOSC1 PS1 Bit 0 FOSC0 PS0 Value on POR, BOR -- 1111 1111 Value on all other Resets -- 1111 1111 ---0 1000
OPTION_REG RABPU INTEDG
WDTPS3 WDTPS2 WSTPS1 WDTPS0 SWDTEN ---0 1000
Shaded cells are not used by the Watchdog Timer. See Register 14-1 for operation of all Configuration Word register bits.
(c) 2007 Microchip Technology Inc.
DS41262D-page 209
PIC16F631/677/685/687/689/690
14.6 Power-Down Mode (Sleep)
The Power-down mode is entered by executing a SLEEP instruction. If the Watchdog Timer is enabled: * * * * * WDT will be cleared but keeps running. PD bit in the STATUS register is cleared. TO bit is set. Oscillator driver is turned off. I/O ports maintain the status they had before SLEEP was executed (driving high, low or highimpedance). When the SLEEP instruction is being executed, the next instruction (PC + 1) is prefetched. For the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). Wake-up occurs 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, then branches to the interrupt address (0004h). In cases where the execution of the instruction following SLEEP is not desirable, the user should have a NOP after the SLEEP instruction. Note: If the global interrupts are disabled (GIE is cleared), but any interrupt source has both its interrupt enable bit and the corresponding interrupt flag bits set, the device will immediately wake-up from Sleep. The SLEEP instruction is completely executed.
For lowest current consumption in this mode, all I/O pins should be either at VDD or VSS, with no external circuitry drawing current from the I/O pin and the comparators and CVREF should be disabled. I/O pins that are highimpedance inputs should be pulled 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 pullups on PORTA should be considered. The MCLR pin must be at a logic high level. Note: It should be noted that a Reset generated by a WDT time-out does not drive MCLR pin low.
The WDT is cleared when the device wakes up from Sleep, regardless of the source of wake-up.
14.6.2
WAKE-UP USING INTERRUPTS
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 the interrupt occurs before the execution of a SLEEP instruction, the SLEEP instruction will complete as a NOP. Therefore, the WDT and WDT prescaler and postscaler (if enabled) will not be cleared, the TO bit will not be set and the PD bit will not be cleared. * If the interrupt 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 prescaler and postscaler (if enabled) 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.
14.6.1
WAKE-UP FROM SLEEP
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 RA2/INT pin, PORTA change or a peripheral interrupt.
The first event will cause a device Reset. The two latter events are considered a continuation of program execution. The TO and PD bits in the STATUS register can be used to determine the cause of device Reset. The PD bit, which is set on power-up, is cleared when Sleep is invoked. TO bit is cleared if WDT Wake-up occurred. The following peripheral interrupts can wake the device from Sleep: 1. 2. 3. 4. 5. 6. 7. 8. TMR1 interrupt. Timer1 must be operating as an asynchronous counter. ECCP Capture mode interrupt. A/D conversion (when A/D clock source is FRC). EEPROM write operation completion. Comparator output changes state. Interrupt-on-change. External Interrupt from INT pin. EUSART Break detect, I2C slave.
Other peripherals cannot generate interrupts since during Sleep, no on-chip clocks are present.
DS41262D-page 210
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 14-10: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 TOST(2) Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 OSC1 CLKOUT(4) INT pin INTF flag (INTCON<1>) GIE bit (INTCON<7>) Instruction Flow PC Instruction Fetched Instruction Executed Note 1: 2: 3: 4: Processor in Sleep Interrupt Latency (3)
PC Inst(PC) = Sleep Inst(PC - 1)
PC + 1 Inst(PC + 1) Sleep
PC + 2
PC + 2 Inst(PC + 2) Inst(PC + 1)
PC + 2
0004h Inst(0004h)
0005h Inst(0005h) Inst(0004h)
Dummy Cycle
Dummy Cycle
XT, HS or LP Oscillator mode assumed. TOST = 1024 TOSC (drawing not to scale). This delay does not apply to EC and RC Oscillator modes. GIE = 1 assumed. In this case after wake-up, the processor jumps to 0004h. If GIE = 0, execution will continue in-line. CLKOUT is not available in XT, HS, LP or EC Oscillator modes, but shown here for timing reference.
14.7
Code Protection
If the code protection bit(s) have not been programmed, the on-chip program memory can be read out using ICSPTM for verification purposes. Note: The entire data EEPROM and Flash program memory will be erased when the code protection is switched from on to off. See the "PIC12F6XX/16F6XX Memory Programming Specification" (DS41204) for more information.
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. The device is placed into a Program/Verify mode by holding the RA0/AN0/C1IN+/ICSPDAT/ULPWU and RA1/AN1/C12IN-/VREF/ICSPCLK pins low, while raising the MCLR (VPP) pin from VIL to VIHH. See the "PIC12F6XX/16F6XX Memory Programming Specification" (DS41204) for more information. RA0 becomes the programming data and RA1 becomes the programming clock. Both RA0 and RA1 are Schmitt Trigger inputs in this mode. After Reset, to place the device into Program/Verify mode, the Program Counter (PC) is at location 00h. A 6-bit command is then supplied to the device. Depending on the command, 14 bits of program data are then supplied to or from the device, depending on whether the command was a load or a read. For complete details of serial programming, please refer to the "PIC12F6XX/16F6XX Memory Programming Specification" (DS41204). A typical In-Circuit Serial Programming connection is shown in Figure 14-11.
14.8
ID Locations
Four memory locations (2000h-2003h) are designated as ID locations where the user can store checksum or other code identification numbers. These locations are not accessible during normal execution but are readable and writable during Program/Verify mode. Only the Least Significant 7 bits of the ID locations are used.
14.9
In-Circuit Serial Programming
The PIC16F631/677/685/687/689/690 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 * programming voltage
(c) 2007 Microchip Technology Inc.
DS41262D-page 211
PIC16F631/677/685/687/689/690
FIGURE 14-11: TYPICAL IN-CIRCUIT SERIAL PROGRAMMING CONNECTION
To Normal Connections External Connector Signals +5V 0V VPP CLK Data I/O * PIC16F631/677/ 685/687/689/690 VDD VSS RA3/MCLR/VPP RA1 RA0
*
*
*
To Normal Connections * Isolation devices (as required)
DS41262D-page 212
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
15.0 INSTRUCTION SET SUMMARY
TABLE 15-1:
Field
f W b k x
The PIC16F690 instruction set is highly orthogonal and is comprised of three basic categories: * Byte-oriented operations * Bit-oriented operations * Literal and control operations Each PIC16 instruction is a 14-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 formats for each of the categories is presented in Figure 15-1, while the various opcode fields are summarized in Table 15-1. Table 15-2 lists the instructions recognized by the MPASMTM assembler. For byte-oriented instructions, `f' represents a file register designator and `d' represents a destination designator. The file register designator specifies which file register is to be used by the instruction. The destination designator specifies where the result of the operation is to be placed. If `d' is zero, the result is placed in the W register. If `d' is one, the result is placed in the file register specified in the instruction. For bit-oriented instructions, `b' represents a bit field designator, which selects the bit affected by the operation, while `f' represents the address of the file in which the bit is located. For literal and control operations, `k' represents an 8-bit or 11-bit constant, or literal value. One instruction cycle consists of four oscillator periods; for an oscillator frequency of 4 MHz, this gives a normal instruction execution time of 1 s. All instructions are executed within a single instruction cycle, unless a conditional test is true, or the program counter is changed as a result of an instruction. When this occurs, the execution takes two instruction cycles, with the second cycle executed as a NOP. All instruction examples use the format `0xhh' to represent a hexadecimal number, where `h' signifies a hexadecimal digit.
OPCODE FIELD DESCRIPTIONS
Description
Register file address (0x00 to 0x7F) Working register (accumulator) Bit address within an 8-bit file register Literal field, constant data or label Don't care location (= 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. Destination select; d = 0: store result in W, d = 1: store result in file register f. Default is d = 1. Program Counter Time-out bit Carry bit Digit carry bit Zero bit Power-down bit
d
PC TO C DC Z PD
FIGURE 15-1:
GENERAL FORMAT FOR INSTRUCTIONS
0
Byte-oriented file register operations 13 876 OPCODE d f (FILE #) d = 0 for destination W d = 1 for destination f f = 7-bit file register address Bit-oriented file register operations 13 10 9 76 OPCODE b (BIT #) f (FILE #) b = 3-bit bit address f = 7-bit file register address Literal and control operations General 13 OPCODE 8 7 k (literal)
0
15.1
Read-Modify-Write Operations
0
Any instruction that specifies a file register as part of the instruction performs a Read-Modify-Write (RMW) operation. The register is read, the data is modified, and the result is stored according to either the instruction, or the destination designator `d'. A read operation is performed on a register even if the instruction writes to that register. For example, a CLRF PORTA instruction will read PORTA, clear all the data bits, then write the result back to PORTA. This example would have the unintended consequence of clearing the condition that set the RAIF flag.
k = 8-bit immediate value CALL and GOTO instructions only 13 11 OPCODE 10 k (literal) 0
k = 11-bit immediate value
(c) 2007 Microchip Technology Inc.
DS41262D-page 213
PIC16F631/677/685/687/689/690
TABLE 15-2:
Mnemonic, Operands
PIC16F684 INSTRUCTION SET
14-Bit Opcode Description Cycles MSb BYTE-ORIENTED FILE REGISTER OPERATIONS LSb Status Affected Notes
ADDWF ANDWF CLRF CLRW COMF DECF DECFSZ INCF INCFSZ IORWF MOVF MOVWF NOP RLF RRF SUBWF SWAPF XORWF
f, d f, d f - f, d f, d f, d f, d f, d f, d f, d f - f, d f, d f, d f, d f, d
Add W and f AND W with f Clear f Clear W Complement f Decrement f Decrement f, Skip if 0 Increment f Increment f, Skip if 0 Inclusive OR W with f Move f Move W to f No Operation Rotate Left f through Carry Rotate Right f through Carry Subtract W from f Swap nibbles in f Exclusive OR W with f
1 1 1 1 1 1 1(2) 1 1(2) 1 1 1 1 1 1 1 1 1
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0111 0101 0001 0001 1001 0011 1011 1010 1111 0100 1000 0000 0000 1101 1100 0010 1110 0110
dfff dfff lfff 0xxx dfff dfff dfff dfff dfff dfff dfff lfff 0xx0 dfff dfff dfff dfff dfff
ffff ffff ffff xxxx ffff ffff ffff ffff ffff ffff ffff ffff 0000 ffff ffff ffff ffff ffff
C, DC, Z Z Z Z Z Z Z Z Z
1, 2 1, 2 2 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2 1, 2
C C C, DC, Z Z
1, 2 1, 2 1, 2 1, 2 1, 2
BIT-ORIENTED FILE REGISTER OPERATIONS BCF BSF BTFSC BTFSS ADDLW ANDLW CALL CLRWDT GOTO IORLW MOVLW RETFIE RETLW RETURN SLEEP SUBLW XORLW Note 1: f, b f, b f, b f, b k k k - k k k - k - - k k Bit Clear f Bit Set f Bit Test f, Skip if Clear Bit Test f, Skip if Set Add literal and W AND literal with W Call Subroutine Clear Watchdog Timer Go to address Inclusive OR literal with W Move literal to W Return from interrupt Return with literal in W Return from Subroutine Go into Standby mode Subtract W from literal Exclusive OR literal with W 1 1 1 (2) 1 (2) 1 1 2 1 2 1 1 2 2 2 1 1 1 01 01 01 01 00bb 01bb 10bb 11bb bfff bfff bfff bfff ffff ffff ffff ffff C, DC, Z Z TO, PD Z 1, 2 1, 2 3 3
LITERAL AND CONTROL OPERATIONS 11 11 10 00 10 11 11 00 11 00 00 11 11 111x 1001 0kkk 0000 1kkk 1000 00xx 0000 01xx 0000 0000 110x 1010 kkkk kkkk kkkk 0110 kkkk kkkk kkkk 0000 kkkk 0000 0110 kkkk kkkk kkkk kkkk kkkk 0100 kkkk kkkk kkkk 1001 kkkk 1000 0011 kkkk kkkk
TO, PD C, DC, Z Z
2: 3:
When an I/O register is modified as a function of itself (e.g., MOVF GPIO, 1), 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'. If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared if assigned to the Timer0 module. If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP.
DS41262D-page 214
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
15.2
ADDLW Syntax: Operands: Operation: Status Affected: Description:
Instruction Descriptions
Add literal and W [ label ] ADDLW 0 k 255 (W) + k (W) C, DC, Z The contents of the W register are added to the eight-bit literal `k' and the result is placed in the W register. Operation: Status Affected: Description: k BCF Syntax: Operands: Bit Clear f [ label ] BCF 0 f 127 0b7 0 (f) None Bit `b' in register `f' is cleared. f,b
ADDWF Syntax: Operands: Operation: Status Affected: Description:
Add W and f [ label ] ADDWF 0 f 127 d [0,1] (W) + (f) (destination) C, DC, Z Add the contents of the W register with register `f'. If `d' is `0', the result is stored in the W register. If `d' is `1', the result is stored back in register `f'. f,d
BSF Syntax: Operands: Operation: Status Affected: Description:
Bit Set f [ label ] BSF 0 f 127 0b7 1 (f) None Bit `b' in register `f' is set. f,b
ANDLW Syntax: Operands: Operation: Status Affected: Description:
AND literal with W [ label ] ANDLW 0 k 255 (W) .AND. (k) (W) Z The contents of W register are AND'ed with the eight-bit literal `k'. The result is placed in the W register. k
BTFSC Syntax: Operands: Operation: Status Affected: Description:
Bit Test f, Skip if Clear [ label ] BTFSC f,b 0 f 127 0b7 skip if (f) = 0 None If bit `b' in register `f' is `1', the next instruction is executed. If bit `b' in register `f' is `0', the next instruction is discarded, and a NOP is executed instead, making this a two-cycle instruction.
ANDWF Syntax: Operands: Operation: Status Affected: Description:
AND W with f [ label ] ANDWF 0 f 127 d [0,1] (W) .AND. (f) (destination) Z AND the W register with register `f'. If `d' is `0', the result is stored in the W register. If `d' is `1', the result is stored back in register `f'. f,d
(c) 2007 Microchip Technology Inc.
DS41262D-page 215
PIC16F631/677/685/687/689/690
BTFSS Syntax: Operands: Operation: Status Affected: Description: Bit Test f, Skip if Set [ label ] BTFSS f,b 0 f 127 0b<7 skip if (f) = 1 None If bit `b' in register `f' is `0', the next instruction is executed. If bit `b' is `1', then the next instruction is discarded and a NOP is executed instead, making this a two-cycle instruction. Status Affected: Description: CLRWDT Syntax: Operands: Operation: Clear Watchdog Timer [ label ] CLRWDT None 00h WDT 0 WDT prescaler, 1 TO 1 PD TO, PD CLRWDT instruction resets the Watchdog Timer. It also resets the prescaler of the WDT. Status bits TO and PD are set.
CALL Syntax: Operands: Operation:
Call Subroutine [ label ] CALL k 0 k 2047 (PC)+ 1 TOS, k PC<10:0>, (PCLATH<4:3>) PC<12:11> None Call Subroutine. First, return address (PC + 1) is pushed onto the stack. The eleven-bit immediate address is loaded into PC bits <10:0>. The upper bits of the PC are loaded from PCLATH. CALL is a two-cycle instruction.
COMF Syntax: Operands: Operation: Status Affected: Description:
Complement f [ label ] COMF 0 f 127 d [0,1] (f) (destination) Z 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'. f,d
Status Affected: Description:
CLRF Syntax: Operands: Operation: Status Affected: Description:
Clear f [ label ] CLRF 0 f 127 00h (f) 1Z Z The contents of register `f' are cleared and the Z bit is set. f
DECF Syntax: Operands: Operation: Status Affected: Description:
Decrement f [ label ] DECF f,d 0 f 127 d [0,1] (f) - 1 (destination) Z Decrement register `f'. If `d' is `0', the result is stored in the W register. If `d' is `1', the result is stored back in register `f'.
CLRW Syntax: Operands: Operation: Status Affected: Description:
Clear W [ label ] CLRW None 00h (W) 1Z Z W register is cleared. Zero bit (Z) is set.
DS41262D-page 216
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
DECFSZ Syntax: Operands: Operation: Status Affected: Description: Decrement f, Skip if 0 [ label ] DECFSZ f,d 0 f 127 d [0,1] (f) - 1 (destination); skip if result = 0 None The contents of register `f' are decremented. If `d' is `0', the result is placed in the W register. If `d' is `1', the result is placed back in register `f'. If the result is `1', the next instruction is executed. If the result is `0', then a NOP is executed instead, making it a two-cycle instruction. INCFSZ Syntax: Operands: Operation: Status Affected: Description: Increment f, Skip if 0 [ label ] INCFSZ f,d 0 f 127 d [0,1] (f) + 1 (destination), skip if result = 0 None The contents of register `f' are incremented. If `d' is `0', the result is placed in the W register. If `d' is `1', the result is placed back in register `f'. If the result is `1', the next instruction is executed. If the result is `0', a NOP is executed instead, making it a two-cycle instruction.
GOTO Syntax: Operands: Operation: Status Affected: Description:
Unconditional Branch [ label ] GOTO k 0 k 2047 k PC<10:0> PCLATH<4:3> PC<12:11> None GOTO is an unconditional branch. The eleven-bit immediate value is loaded into PC bits <10:0>. The upper bits of PC are loaded from PCLATH<4:3>. GOTO is a two-cycle instruction.
IORLW Syntax: Operands: Operation: Status Affected: Description:
Inclusive OR literal with W [ label ] IORLW k 0 k 255 (W) .OR. k (W) Z The contents of the W register are OR'ed with the eight-bit literal `k'. The result is placed in the W register.
INCF Syntax: Operands: Operation: Status Affected: Description:
Increment f [ label ] INCF f,d 0 f 127 d [0,1] (f) + 1 (destination) Z The contents of register `f' are incremented. If `d' is `0', the result is placed in the W register. If `d' is `1', the result is placed back in register `f'.
IORWF Syntax: Operands: Operation: Status Affected: Description:
Inclusive OR W with f [ label ] IORWF f,d 0 f 127 d [0,1] (W) .OR. (f) (destination) Z Inclusive OR the W register with register `f'. If `d' is `0', the result is placed in the W register. If `d' is `1', the result is placed back in register `f'.
(c) 2007 Microchip Technology Inc.
DS41262D-page 217
PIC16F631/677/685/687/689/690
MOVF Syntax: Operands: Operation: Status Affected: Description: Move f [ label ] MOVF f,d 0 f 127 d [0,1] (f) (dest) Z The contents of register `f' is moved to a destination dependent upon the status of `d'. If d = 0, destination is W register. If d = 1, the destination is file register `f' itself. d = 1 is useful to test a file register since status flag Z is affected. 1 1
MOVF FSR, 0
MOVWF Syntax: Operands: Operation: Status Affected: Description: Words: Cycles: Example:
Move W to f [ label ] (W) (f) None Move data from W register to register `f'. 1 1 MOVW F OPTION MOVWF f 0 f 127
Words: Cycles: Example:
Before Instruction OPTION = W = After Instruction OPTION = W =
0xFF 0x4F 0x4F 0x4F
After Instruction W= value in FSR register Z=1
MOVLW Syntax: Operands: Operation: Status Affected: Description:
Move literal to W [ label ] k (W) None The eight-bit literal `k' is loaded into W register. The "don't cares" will assemble as `0's. 1 1
MOVLW 0x5A
NOP Syntax: Operands: Operation: Status Affected: Description: Words: Cycles: Example:
No Operation [ label ] None No operation None No operation. 1 1
NOP
MOVLW k
NOP
0 k 255
Words: Cycles: Example:
After Instruction W=
0x5A
DS41262D-page 218
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
RETFIE Syntax: Operands: Operation: Status Affected: Description: Return from Interrupt [ label ] None TOS PC, 1 GIE None Return from Interrupt. Stack is POPed and Top-of-Stack (TOS) is loaded in the PC. Interrupts are enabled by setting Global Interrupt Enable bit, GIE (INTCON<7>). This is a two-cycle instruction. 1 2
RETFIE
RETLW Syntax: Operands: Operation: Status Affected: Description:
Return with literal in W [ label ] RETLW k 0 k 255 k (W); TOS PC None The W register is loaded with the eight-bit literal `k'. The program counter is loaded from the top of the stack (the return address). This is a two-cycle instruction. 1 2 CALL TABLE;W contains table ;offset value * ;W now has * ;table value * * ADDWF PC ;W = offset RETLW k1 ;Begin table RETLW k2 ; * * * RETLW kn ;End of table Before Instruction W = 0x07 After Instruction W = value of k8
RETFIE
Words: Cycles: Example:
Words: Cycles: Example:
After Interrupt PC = GIE =
TABLE TOS 1
RETURN Syntax: Operands: Operation: Status Affected: Description:
Return from Subroutine [ label ] None TOS PC None Return from subroutine. The stack is POPed and the top of the stack (TOS) is loaded into the program counter. This is a two-cycle instruction. RETURN
(c) 2007 Microchip Technology Inc.
DS41262D-page 219
PIC16F631/677/685/687/689/690
RLF Syntax: Operands: Operation: Status Affected: Description: Rotate Left f through Carry [ label ] 0 f 127 d [0,1] See description below C 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 the W register. If `d' is `1', the result is stored back in register `f'.
C Register f
SLEEP Syntax: Operands: Operation:
Enter Sleep mode [ label ] SLEEP None 00h WDT, 0 WDT prescaler, 1 TO, 0 PD TO, PD The power-down Status bit, PD is cleared. Time-out Status bit, TO is set. Watchdog Timer and its prescaler are cleared. The processor is put into Sleep mode with the oscillator stopped.
RLF
f,d
Status Affected: Description:
Words: Cycles: Example:
1 1
RLF REG1,0 REG1 C = = = = = 1110 0110 0 1110 0110 1100 1100 1
Before Instruction
After Instruction
REG1 W C
RRF Syntax: Operands: Operation: Status Affected: Description:
Rotate Right f through Carry [ label ] RRF f,d 0 f 127 d [0,1] See description below C 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 the W register. If `d' is `1', the result is placed back in register `f'.
C Register f
SUBLW Syntax: Operands: Operation: Description:
Subtract W from literal [ label ] SUBLW k 0 k 255 k - (W) (W) The W register is subtracted (2's complement method) from the eight-bit literal `k'. The result is placed in the W register. C=0 C=1 DC = 0 DC = 1 W>k Wk W<3:0> > k<3:0> W<3:0> k<3:0>
Status Affected: C, DC, Z
DS41262D-page 220
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
SUBWF Syntax: Operands: Operation: Description: Subtract W from f [ label ] SUBWF f,d 0 f 127 d [0,1] (f) - (W) (destination) Subtract (2's complement method) W register from register `f'. If `d' is `0', the result is stored in the W register. If `d' is `1', the result is stored back in register `f'. C=0 C=1 DC = 0 DC = 1 W>f Wf W<3:0> > f<3:0> W<3:0> f<3:0> XORLW Syntax: Operands: Operation: Status Affected: Description: Exclusive OR literal with W [ label ] XORLW k 0 k 255 (W) .XOR. k (W) Z The contents of the W register are XOR'ed with the eight-bit literal `k'. The result is placed in the W register.
Status Affected: C, DC, Z
SWAPF Syntax: Operands: Operation: Status Affected: Description:
Swap Nibbles in f [ label ] SWAPF f,d 0 f 127 d [0,1] (f<3:0>) (destination<7:4>), (f<7:4>) (destination<3:0>) None The upper and lower nibbles of register `f' are exchanged. If `d' is `0', the result is placed in the W register. If `d' is `1', the result is placed in register `f'.
XORWF Syntax: Operands: Operation: Status Affected: Description:
Exclusive OR W with f [ label ] XORWF 0 f 127 d [0,1] (W) .XOR. (f) (destination) Z Exclusive OR the contents of the W register with register `f'. If `d' is `0', the result is stored in the W register. If `d' is `1', the result is stored back in register `f'. f,d
(c) 2007 Microchip Technology Inc.
DS41262D-page 221
PIC16F631/677/685/687/689/690
NOTES:
DS41262D-page 222
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
16.0 DEVELOPMENT SUPPORT
16.1
The PIC(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 C18 and MPLAB C30 C Compilers - MPLINKTM Object Linker/ MPLIBTM Object Librarian - MPLAB ASM30 Assembler/Linker/Library * Simulators - MPLAB SIM Software Simulator * Emulators - MPLAB ICE 2000 In-Circuit Emulator - MPLAB REAL ICETM In-Circuit Emulator * In-Circuit Debugger - MPLAB ICD 2 * Device Programmers - PICSTART(R) Plus Development Programmer - MPLAB PM3 Device Programmer - PICkitTM 2 Development Programmer * Low-Cost Demonstration and Development Boards and Evaluation Kits
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) operating system-based application that contains: * A single graphical interface to all 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 * Visual device initializer for easy register initialization * Mouse over variable inspection * Drag and drop variables from source to watch windows * Extensive on-line help * Integration of select third party tools, such as HI-TECH Software C Compilers and IAR C Compilers The MPLAB IDE allows you to: * Edit your source files (either assembly or C) * One touch assemble (or compile) and download to PIC MCU emulator and simulator tools (automatically updates all project information) * Debug using: - Source files (assembly or C) - 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 increased flexibility and power.
(c) 2007 Microchip Technology Inc.
DS41262D-page 223
PIC16F631/677/685/687/689/690
16.2 MPASM Assembler 16.5
The MPASM Assembler is a full-featured, universal macro assembler for all PIC 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 contain 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
MPLAB ASM30 Assembler, Linker and Librarian
MPLAB ASM30 Assembler produces relocatable machine code from symbolic assembly language for dsPIC30F devices. MPLAB C30 C Compiler uses the assembler to produce its 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
16.6 16.3 MPLAB C18 and MPLAB C30 C Compilers
MPLAB SIM Software Simulator
The MPLAB C18 and MPLAB C30 Code Development Systems are complete ANSI C compilers for Microchip's PIC18 and PIC24 families of microcontrollers and the dsPIC30 and dsPIC33 family of digital signal controllers. 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.
The MPLAB SIM Software Simulator allows code development in a PC-hosted environment by simulating the PIC MCUs and dsPIC(R) DSCs on an instruction level. On any given instruction, the data areas can be examined or modified and stimuli can be applied from a comprehensive stimulus controller. Registers can be logged to files for further run-time analysis. The trace buffer and logic analyzer display extend the power of the simulator to record and track program execution, actions on I/O, most peripherals and internal registers. The MPLAB SIM Software Simulator fully supports symbolic debugging using the MPLAB C18 and MPLAB C30 C Compilers, and the MPASM and MPLAB ASM30 Assemblers. The software simulator offers the flexibility to develop and debug code outside of the hardware laboratory environment, making it an excellent, economical software development tool.
16.4
MPLINK Object Linker/ MPLIB Object Librarian
The MPLINK Object Linker combines relocatable objects created by the MPASM Assembler and the MPLAB C18 C Compiler. It can link relocatable objects from precompiled libraries, using directives from a linker script. The MPLIB Object Librarian manages the creation and modification of library files of precompiled 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
DS41262D-page 224
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
16.7 MPLAB ICE 2000 High-Performance In-Circuit Emulator 16.9 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 PIC MCUs and can be used to develop for these and other PIC MCUs and dsPIC DSCs. 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 costeffective, 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, and 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 PIC devices.
The MPLAB ICE 2000 In-Circuit Emulator is intended to provide the product development engineer with a complete microcontroller design tool set for PIC 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 architecture of the MPLAB ICE 2000 In-Circuit Emulator allows expansion to support new PIC 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(R) 32-bit operating system were chosen to best make these features available in a simple, unified application.
16.10 MPLAB PM3 Device Programmer
The MPLAB PM3 Device Programmer is a universal, CE compliant device programmer with programmable voltage verification at VDDMIN and VDDMAX for maximum reliability. It features a large LCD display (128 x 64) for menus and error messages and a modular, detachable socket assembly to support various package types. The ICSPTM cable assembly is included as a standard item. In Stand-Alone mode, the MPLAB PM3 Device Programmer can read, verify and program PIC devices without a PC connection. It can also set code protection in this mode. The MPLAB PM3 connects to the host PC via an RS-232 or USB cable. The MPLAB PM3 has high-speed communications and optimized algorithms for quick programming of large memory devices and incorporates an SD/MMC card for file storage and secure data applications.
16.8
MPLAB REAL ICE In-Circuit Emulator System
MPLAB REAL ICE In-Circuit Emulator System is Microchip's next generation high-speed emulator for Microchip Flash DSC(R) and MCU devices. It debugs and programs PIC(R) and dsPIC(R) Flash microcontrollers with the easy-to-use, powerful graphical user interface of the MPLAB Integrated Development Environment (IDE), included with each kit. The MPLAB REAL ICE probe is connected to the design engineer's PC using a high-speed USB 2.0 interface and is connected to the target with either a connector compatible with the popular MPLAB ICD 2 system (RJ11) or with the new high speed, noise tolerant, lowvoltage differential signal (LVDS) interconnection (CAT5). MPLAB REAL ICE is field upgradeable through future firmware downloads in MPLAB IDE. In upcoming releases of MPLAB IDE, new devices will be supported, and new features will be added, such as software breakpoints and assembly code trace. MPLAB REAL ICE offers significant advantages over competitive emulators including low-cost, full-speed emulation, real-time variable watches, trace analysis, complex breakpoints, a ruggedized probe interface and long (up to three meters) interconnection cables.
(c) 2007 Microchip Technology Inc.
DS41262D-page 225
PIC16F631/677/685/687/689/690
16.11 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 PIC devices in DIP packages 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.
16.13 Demonstration, Development and Evaluation Boards
A wide variety of demonstration, development and evaluation boards for various PIC MCUs and dsPIC DSCs allows quick application development on fully functional systems. Most boards include prototyping areas for adding custom circuitry and provide application firmware and source code for examination and modification. The boards support a variety of features, including LEDs, temperature sensors, switches, speakers, RS-232 interfaces, LCD displays, potentiometers and additional EEPROM memory. The demonstration and development boards can be used in teaching environments, for prototyping custom circuits and for learning about various microcontroller applications. In addition to the PICDEMTM and dsPICDEMTM demonstration/development board series of circuits, Microchip has a line of evaluation kits and demonstration software for analog filter design, KEELOQ(R) security ICs, CAN, IrDA(R), PowerSmart(R) battery management, SEEVAL(R) evaluation system, Sigma-Delta ADC, flow rate sensing, plus many more. Check the Microchip web page (www.microchip.com) and the latest "Product Selector Guide" (DS00148) for the complete list of demonstration, development and evaluation kits.
16.12 PICkit 2 Development Programmer
The PICkitTM 2 Development Programmer is a low-cost programmer and selected Flash device debugger with an easy-to-use interface for programming many of Microchip's baseline, mid-range and PIC18F families of Flash memory microcontrollers. The PICkit 2 Starter Kit includes a prototyping development board, twelve sequential lessons, software and HI-TECH's PICCTM Lite C compiler, and is designed to help get up to speed quickly using PIC(R) microcontrollers. The kit provides everything needed to program, evaluate and develop applications using Microchip's powerful, mid-range Flash memory family of microcontrollers.
DS41262D-page 226
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
17.0 ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings()
Ambient temperature under bias..........................................................................................................-40 to +125C Storage temperature ........................................................................................................................ -65C to +150C Voltage on VDD with respect to VSS ................................................................................................... -0.3V to +6.5V Voltage on MCLR with respect to Vss ............................................................................................... -0.3V to +13.5V Voltage on all other pins with respect to VSS ........................................................................... -0.3V to (VDD + 0.3V) Total power dissipation(1) ............................................................................................................................... 800 mW 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 PORTA, PORTB and PORTC (combined) ............................................................ 200 mA Maximum current sourced PORTA, PORTB and PORTC (combined)............................................................ 200 mA Note 1: Power dissipation is calculated as follows: PDIS = VDD x {IDD - IOH} + {(VDD - VOH) x IOH} + (VOL x IOL).
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.
Note:
Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up. Thus, a series resistor of 50-100 should be used when applying a "low" level to the MCLR pin, rather than pulling this pin directly to VSS.
(c) 2007 Microchip Technology Inc.
DS41262D-page 227
PIC16F631/677/685/687/689/690
FIGURE 17-1: PIC16F631/677/685/687/689/690 VOLTAGE-FREQUENCY GRAPH, -40C TA +125C
5.5 5.0 4.5 VDD (V) 4.0 3.5 3.0 2.5 2.0 0 8 10 Frequency (MHz) Note 1: The shaded region indicates the permissible combinations of voltage and frequency. 20
FIGURE 17-2:
HFINTOSC FREQUENCY ACCURACY OVER DEVICE VDD AND TEMPERATURE
125 5% 85 Temperature (C)
60
2%
25
1%
0
2.0
2.5
3.0
3.5
4.0 VDD (V)
4.5
5.0
5.5
DS41262D-page 228
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
17.1 DC Characteristics: PIC16F631/677/685/687/689/690-I (Industrial) PIC16F631/677/685/687/689/690-E (Extended)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Min 2.0 2.0 3.0 4.5 1.5 -- Typ Max Units -- -- -- -- -- VSS 5.5 5.5 5.5 5.5 -- -- V V V V V V Conditions FOSC < = 8 MHz: HFINTOSC, EC FOSC < = 4 MHz FOSC < = 10 MHz FOSC < = 20 MHz Device in Sleep mode See Section 14.2.1 "Power-on Reset (POR)" for details.
DC CHARACTERISTICS Param No. D001 D001C D001D D002* D003 VDR VPOR 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
Sym VDD
Characteristic Supply Voltage
D004*
SVDD
0.05
--
--
V/ms See Section 14.2.1 "Power-on Reset (POR)" for details.
* These parameters are characterized but not tested. 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: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
(c) 2007 Microchip Technology Inc.
DS41262D-page 229
PIC16F631/677/685/687/689/690
17.2 DC Characteristics: PIC16F631/677/685/687/689/690-I (Industrial)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Conditions Device Characteristics Supply Current (IDD)(1, 2) Min -- -- -- D011* -- -- -- D012 -- -- -- D013* -- -- -- D014 -- -- -- D015 -- -- -- D016* -- -- -- D017 -- -- -- D018 -- -- -- D019 Legend: Note 1: 2: -- -- Typ 9 18 35 140 220 380 260 420 0.8 130 215 360 220 375 0.65 8 16 31 340 500 0.8 410 700 1.30 230 400 0.63 2.6 2.8 Max TBD TBD TBD 240 380 550 360 650 1.1 220 360 520 340 550 1.0 20 40 65 450 700 1.2 650 950 1.65 400 680 1.1 3.25 3.35 Units VDD A A A A A A A A mA A A A A A mA A A A A A mA A A mA A A mA mA mA 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 4.5 5.0 FOSC = 20 MHz HS Oscillator mode FOSC = 4 MHz EXTRC mode(3) FOSC = 8 MHz HFINTOSC mode FOSC = 4 MHz HFINTOSC mode FOSC = 31 kHz LFINTOSC mode FOSC = 4 MHz EC Oscillator mode FOSC = 1 MHz EC Oscillator mode FOSC = 4 MHz XT Oscillator mode FOSC = 1 MHz XT Oscillator mode Note FOSC = 32 kHz LP Oscillator mode
DC CHARACTERISTICS Param No. D010
3: 4:
5:
TBD = To Be Determined Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. 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 disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 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.
DS41262D-page 230
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
17.2 DC Characteristics: PIC16F631/677/685/687/689/690-I (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial Conditions Device Characteristics Power-down Base Current(IPD)(2) Min -- -- -- -- D021 -- -- -- D022 D023 -- -- -- -- -- D024 -- -- -- D024a* -- -- -- D025 -- -- -- D026 D027 Legend: Note 1: 2: -- -- -- -- Typ 0.15 0.20 0.35 90 1.0 2.0 3.0 42 85 32 60 120 30 45 75 39 59 98 4.0 4.6 6.0 0.30 0.36 TBD TBD Max 1.2 1.5 1.8 500 2.2 4.0 7.0 60 122 45 78 160 36 55 95 47 72 124 TBD TBD TBD 1.6 1.9 TBD TBD Units VDD A A A nA A A A A A A A A A A A A A A A A A A A A A 2.0 3.0 5.0 3.0 2.0 3.0 5.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 3.0 5.0 3.0 5.0 A/D Current(1), no conversion in progress VP6 Current T1OSC Current CVREF Current(1) (low range) CVREF Current(1) (high range) Comparator Current(1), both comparators enabled BOR Current(1) -40C TA +25C WDT Current(1) Note WDT, BOR, Comparators, VREF and T1OSC disabled DC CHARACTERISTICS Param No. D020
3: 4:
5:
TBD = To Be Determined Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. 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 disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 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.
(c) 2007 Microchip Technology Inc.
DS41262D-page 231
PIC16F631/677/685/687/689/690
17.3 DC Characteristics: PIC16F631/677/685/687/689/690-E (Extended)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C for extended Conditions Device Characteristics Supply Current (IDD)(1, 2) Min -- -- -- D011E* -- -- -- D012E -- -- -- D013E* -- -- -- D014E -- -- -- D015E -- -- -- D016E* -- -- -- D017E -- -- -- D018E -- -- -- D019E Legend: Note 1: 2: -- -- Typ 9 18 35 140 220 380 260 420 0.8 130 215 360 220 375 0.65 8 16 31 340 500 0.8 410 700 1.30 230 400 0.63 2.6 2.8 Max TBD TBD TBD 240 380 550 360 650 1.1 220 360 520 340 550 1.0 20 40 65 450 700 1.2 650 950 1.65 400 680 1.1 3.25 3.35 Units VDD A A A A A A A A mA A A A A A mA A A A A A mA A A mA A A mA mA mA 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 4.5 5.0 FOSC = 20 MHz HS Oscillator mode FOSC = 4 MHz EXTRC mode(3) FOSC = 8 MHz HFINTOSC mode FOSC = 4 MHz HFINTOSC mode FOSC = 31 kHz LFINTOSC mode FOSC = 4 MHz EC Oscillator mode FOSC = 1 MHz EC Oscillator mode FOSC = 4 MHz XT Oscillator mode FOSC = 1 MHz XT Oscillator mode Note FOSC = 32 kHz LP Oscillator mode
DC CHARACTERISTICS Param No. D010E
3: 4:
5:
TBD = To Be Determined Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. 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 disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 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.
DS41262D-page 232
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
17.3 DC Characteristics: PIC16F631/677/685/687/689/690-E (Extended)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C for extended Conditions Device Characteristics Power-down Base Current(IPD)(2) Min -- -- -- -- D021E -- -- -- D022E D023E -- -- -- -- -- D024E -- -- -- D024AE* -- -- -- D025E -- -- -- D026E D027E Legend: Note 1: 2: -- -- -- -- Typ 0.15 0.20 0.35 90 1.0 2.0 3.0 42 85 32 60 120 30 45 75 39 59 98 4.0 4.6 6.0 0.30 0.36 TBD TBD Max 1.2 1.5 1.8 500 2.2 4.0 7.0 60 122 45 78 160 36 55 95 47 72 124 TBD TBD TBD 1.6 1.9 TBD TBD Units VDD A A A nA A A A A A A A A A A A A A A A A A A A A A 2.0 3.0 5.0 3.0 2.0 3.0 5.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 2.0 3.0 5.0 3.0 5.0 3.0 5.0 A/D Current(1), no conversion in progress VP6 Current T1OSC Current CVREF Current(1) (low range) CVREF Current(1) (high range) Comparator Current(1), both comparators enabled BOR Current(1) -40C TA +25C WDT Current(1) Note WDT, BOR, Comparators, VREF and T1OSC disabled DC CHARACTERISTICS Param No. D020E
3: 4:
5:
TBD = To Be Determined Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. 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 disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 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.
(c) 2007 Microchip Technology Inc.
DS41262D-page 233
PIC16F631/677/685/687/689/690
17.4 DC Characteristics: PIC16F631/677/685/687/689/690-I (Industrial) PIC16F631/677/685/687/689/690-E (Extended)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Characteristic Input Low Voltage I/O Port: D030 D030A D031 D032 D033 D033A VIH D040 D040A D041 D042 D043 D043A D043B IIL D060 D061 D063 D070* D080 VOH D090 * Note 1: 2: 3: 4: 5: IPUR VOL with Schmitt Trigger buffer MCLR OSC1 (XT and LP modes) OSC1 (HS mode) OSC1 (RC mode) Input Leakage Current(2) I/O ports MCLR(3) OSC1 PORTA Weak Pull-up Current Output Low Voltage(5) I/O ports Output High I/O ports Voltage(5) VDD - 0.7 -- -- V IOH = -3.0 mA, VDD = 4.5V (Ind.) -- -- 0.6 V IOL = 8.5 mA, VDD = 4.5V (Ind.) -- -- -- 50 0.1 0.1 0.1 250 1 5 5 400 A A A A VSS VPIN VDD, Pin at high-impedance VSS VPIN VDD VSS VPIN VDD, XT, HS and LP oscillator configuration VDD = 5.0V, VPIN = VSS with Schmitt Trigger buffer MCLR, OSC1 (RC mode)(1) OSC1 (XT and LP modes) OSC1 (HS mode) Input High Voltage I/O Ports: with TTL buffer 2.0 0.25 VDD + 0.8 0.8 VDD 0.8 VDD 1.6 0.7 VDD 0.9 VDD -- -- -- -- -- -- -- -- VDD VDD VDD VDD VDD VDD VDD V V V V V V V (Note 1) 4.5V VDD 5.5V 2.0V VDD 4.5V 2.0V VDD 5.5V with TTL buffer Vss Vss Vss VSS VSS VSS -- -- -- -- -- -- 0.8 0.15 VDD 0.2 VDD 0.2 VDD 0.3 0.3 VDD V V V V V V 4.5V VDD 5.5V 2.0V VDD 4.5V 2.0V VDD 5.5V Min Typ Max Units Conditions
DC CHARACTERISTICS Param No.
Sym VIL
These parameters are characterized but not tested. Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external clock in RC mode. Negative current is defined as current sourced by the pin. 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. See Section 10.2.1 "Using the Data EEPROM" for additional information. Including OSC2 in CLKOUT mode.
DS41262D-page 234
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
17.4 DC Characteristics: PIC16F631/677/685/687/689/690-I (Industrial) PIC16F631/677/685/687/689/690-E (Extended) (Continued)
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +85C for industrial -40C TA +125C for extended Characteristic Ultra Low-Power Wake-up Current Min -- Typ 200 Max -- Units nA Conditions See Application Note AN879, "Using the Microchip Ultra Low-Power Wake-up Module" (DS00879)
DC CHARACTERISTICS Param No. D100
Sym IULP
Capacitive Loading Specs on Output Pins D101* COSC2 OSC2 pin -- -- 15 pF In XT, HS and LP modes when external clock is used to drive OSC1
D101A* CIO D120 D120A D121 ED ED VDRW
All I/O pins Data EEPROM Memory Byte Endurance Byte Endurance VDD for Read/Write
-- 100K 10K VMIN
-- 1M 100K --
50 -- -- 5.5
pF E/W E/W V -40C TA +85C +85C TA +125C Using EECON1 to read/write VMIN = Minimum operating voltage
D122 D123 D124
TDEW TRETD TREF
Erase/Write Cycle Time Characteristic Retention Number of Total Erase/Write Cycles before Refresh(4) Program Flash Memory Cell Endurance Cell Endurance VDD for Read VDD for Erase/Write Erase/Write cycle time Characteristic Retention
-- 40 1M
5 -- 10M
6 -- --
ms Year Provided no other specifications are violated E/W -40C TA +85C
D130 D130A D131 D132 D133 D134
EP ED VPR VPEW TPEW TRETD *
10K 1K VMIN 4.5 -- 40
100K 10K -- -- 2 --
-- -- 5.5 5.5 2.5 --
E/W E/W V V ms
-40C TA +85C +85C TA +125C VMIN = Minimum operating voltage
Year Provided no other specifications are violated
Note 1: 2: 3: 4: 5:
These parameters are characterized but not tested. Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external clock in RC mode. Negative current is defined as current sourced by the pin. 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. See Section 10.2.1 "Using the Data EEPROM" for additional information. Including OSC2 in CLKOUT mode.
(c) 2007 Microchip Technology Inc.
DS41262D-page 235
PIC16F631/677/685/687/689/690
17.5 Thermal Considerations
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C Param No. TH01 JA Sym Characteristic Thermal Resistance Junction to Ambient Typ 62.4 85.2 108.1 40 28.1 24.2 32.2 2.5 150 -- -- Units C/W C/W C/W C/W C/W C/W C/W C/W C W W Conditions
TH02
TH03 TH04 TH05 TH06 TH07 Note 1: 2: 3:
20-pin PDIP package 20-pin SOIC package 20-pin SSOP package 20-pin QFN 4x4mm package JC Thermal Resistance 20-pin PDIP package Junction to Case 20-pin SOIC package 20-pin SSOP package 20-pin QFN 4x4mm package TDIE Die Temperature For derated power calculations PD Power Dissipation PD = PINTERNAL + PI/O PINTERNAL Internal Power Dissipation PINTERNAL = IDD x VDD (NOTE 1) PI/O I/O Power Dissipation -- W PI/O = (IOL * VOL) + (IOH * (VDD - VOH)) PDER Derated Power -- W PDER = PDMAX (TDIE - TA)/JA (NOTE 2, 3) IDD is current to run the chip alone without driving any load on the output pins. TA = Ambient Temperature. Maximum allowable power dissipation is the lower value of either the absolute maximum total power dissipation or derated power.
DS41262D-page 236
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
17.6 Timing Parameter Symbology
The timing parameter symbols have been created with one of the following formats: 1. TppS2ppS 2. TppS T F Frequency Lowercase letters (pp) and their meanings: pp cc CCP1 ck CLKOUT 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 (High-impedance) L Low
T
Time
osc rd rw sc ss t0 t1 wr
OSC1 RD RD or WR SCK SS T0CKI T1CKI WR
P R V Z
Period Rise Valid High-impedance
FIGURE 17-3:
LOAD CONDITIONS
Load Condition
Pin
CL
VSS
Legend: CL =
50 pF 15 pF
for all pins for OSC2 output
(c) 2007 Microchip Technology Inc.
DS41262D-page 237
PIC16F631/677/685/687/689/690
17.7 AC Characteristics: PIC16F631/677/685/687/689/690 (Industrial, Extended)
CLOCK TIMING
Q4 Q1 Q2 Q3 Q4 Q1
FIGURE 17-4:
OSC1/CLKIN OS02 OS04 OS03 OSC2/CLKOUT (LP,XT,HS Modes) OS04
OSC2/CLKOUT (CLKOUT Mode)
TABLE 17-1:
CLOCK OSCILLATOR TIMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C Param No. OS01 Sym FOSC Characteristic External CLKIN Frequency(1) Min DC DC DC DC Oscillator Frequency(1) -- 0.1 1 DC OS02 TOSC External CLKIN Period(1) 27 250 50 50 Oscillator Period(1) -- 250 50 250 OS03 OS04* TCY TOSH, TOSL TOSR, TOSF * Note 1: Instruction Cycle Time(1) External CLKIN High, External CLKIN Low External CLKIN Rise, External CLKIN Fall 200 2 100 20 OS05* 0 0 0 Typ -- -- -- -- 32.768 -- -- -- -- -- -- -- 30.5 -- -- -- TCY -- -- -- -- -- -- Max 37 4 20 20 -- 4 20 4 -- 10,000 1,000 -- DC -- -- -- Units kHz MHz MHz MHz kHz MHz MHz MHz s ns ns ns s ns ns ns ns s ns ns ns ns ns Conditions LP Oscillator mode XT Oscillator mode HS Oscillator mode EC Oscillator mode LP Oscillator mode XT Oscillator mode HS Oscillator mode RC Oscillator mode LP Oscillator mode XT Oscillator mode HS Oscillator mode EC Oscillator mode LP Oscillator mode XT Oscillator mode HS Oscillator mode RC Oscillator mode TCY = 4/FOSC LP oscillator XT oscillator HS oscillator LP oscillator XT oscillator HS oscillator
These parameters are characterized but not tested. Data in "Typ" column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. Instruction cycle period (TCY) equals four times the input oscillator time base period. 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 OSC1 pin. When an external clock input is used, the `max' cycle time limit is `DC' (no clock) for all devices.
DS41262D-page 238
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 17-2: OSCILLATOR PARAMETERS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. OS06 OS07 OS08 Sym TWARM TSC HFOSC Characteristic Internal Oscillator Switch when running(3) Fail-Safe Sample Clock Period(1) Internal Calibrated HFINTOSC Frequency(2) Freq Tolerance -- -- 1% 2% 5% Min -- -- 7.92 7.84 7.60 Typ -- 21 8.0 8.0 8.0 Max 2 -- 8.08 8.16 8.40 Units TOSC ms MHz MHz MHz Conditions Slowest clock LFINTOSC/64 VDD = 3.5V, 25C 2.5V VDD 5.5V, 0C TA +85C 2.0V VDD 5.5V, -40C TA +85C (Ind.), -40C TA +125C (Ext.)
OS09* OS10*
LFOSC
Internal Uncalibrated LFINTOSC Frequency
-- -- -- --
15 5.5 3.5 3
31 12 7 6
45 24 14 11
kHz s s s VDD = 2.0V, -40C to +85C VDD = 3.0V, -40C to +85C VDD = 5.0V, -40C to +85C
TIOSC ST HFINTOSC Oscillator Wake-up from Sleep Start-up Time *
Note 1:
2: 3:
These parameters are characterized but not tested. Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. Instruction cycle period (TCY) equals four times the input oscillator time base period. 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 pin. When an external clock input is used, the `max' cycle time limit is `DC' (no clock) for all devices. To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the device as possible. 0.1 F and 0.01 F values in parallel are recommended. By design.
(c) 2007 Microchip Technology Inc.
DS41262D-page 239
PIC16F631/677/685/687/689/690
FIGURE 17-5:
Cycle
CLKOUT AND I/O TIMING
Write Q4 Fetch Q1 Read Q2 Execute Q3
FOSC OS11 CLKOUT OS19 OS13 I/O pin (Input) OS15 I/O pin (Output) Old Value OS18, OS19 OS14 New Value OS17 OS20 OS21 OS16 OS18 OS12
TABLE 17-3:
CLKOUT AND I/O TIMING PARAMETERS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. OS11 OS12 OS13 OS14 OS15 OS16 OS17 OS18 OS19 OS20* OS21* * Note 1: 2: Sym TOSH2CKL TOSH2CKH TCKL2IOV TIOV2CKH TOSH2IOV TOSH2IOI TIOV2OSH TIOR TIOF TINP TRAP Characteristic FOSC to CLKOUT (1) FOSC to CLKOUT
(1)
Min -- -- -- TOSC + 200 ns -- 50 20 -- -- -- -- 25 TCY
Typ -- -- -- -- 50 -- -- 15 40 28 15 -- --
Max 70 72 20 -- 70* -- -- 72 32 55 30 -- --
Units ns ns ns ns ns ns ns ns ns ns ns
Conditions VDD = 5.0V VDD = 5.0V
CLKOUT to port out
valid(1) CLKOUT(1)
Port input valid before
FOSC (Q1 cycle) to port out valid FOSC (Q2 cycle) to port input invalid (I/O in hold time) Port input valid to FOSC (Q2 cycle) (I/O in setup time) Port output rise time(2) Port output fall time(2) INT pin input high or low time PORTA interrupt-on-change new input level time
VDD = 5.0V VDD = 5.0V
VDD = 2.0V VDD = 5.0V VDD = 2.0V VDD = 5.0V
These parameters are characterized but not tested. Data in "Typ" column is at 5.0V, 25C unless otherwise stated. Measurements are taken in RC mode where CLKOUT output is 4 x TOSC. Includes OSC2 in CLKOUT mode.
DS41262D-page 240
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 17-6: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP TIMER TIMING
VDD MCLR Internal POR 33 PWRT Time-out OSC Start-up Time 32 30
Internal Reset(1) Watchdog Timer Reset(1) 34 I/O pins
Note 1: Asserted low.
31 34
FIGURE 17-7:
VDD
BROWN-OUT RESET TIMING AND CHARACTERISTICS
VBOR
VBOR + VHYST
(Device in Brown-out Reset)
(Device not in Brown-out Reset)
37
Reset (due to BOR) *
33*
64 ms delay only if PWRTE bit in the Configuration Word register is programmed to `0'.
(c) 2007 Microchip Technology Inc.
DS41262D-page 241
PIC16F631/677/685/687/689/690
TABLE 17-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER AND BROWN-OUT RESET PARAMETERS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. 30 31 32 33* 34* Sym TMCL TWDT TOST TPWRT TIOZ Characteristic MCLR Pulse Width (low) Watchdog Timer Time-out Period (No Prescaler) Oscillation Start-up Timer Period(1, 2) Power-up Timer Period I/O High-impedance from MCLR Low or Watchdog Timer Reset Brown-out Reset Voltage Brown-out Reset Hysteresis Brown-out Reset Minimum Detection Period Min 2 5 10 10 -- 40 -- Typ -- -- 17 17 1024 65 -- Max -- -- 25 30 -- 140 2.0 Units s s ms ms Conditions VDD = 5V, -40C to +85C VDD = 5V VDD = 5V, -40C to +85C VDD = 5V
TOSC (NOTE 3) ms s
35 36* 37*
VBOR VHYST TBOR
2.0 -- 100
-- 50 --
2.2 -- --
V mV s
(NOTE 4) VDD VBOR
* These parameters are characterized but not tested. Data in "Typ" column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. 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 pin. When an external clock input is used, the `max' cycle time limit is `DC' (no clock) for all devices. 2: By design. 3: Period of the slower clock. 4: To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the device as possible. 0.1 F and 0.01 F values in parallel are recommended.
DS41262D-page 242
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 17-8: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI 40 41
42
T1CKI 45 47 46 49
TMR0 or TMR1
TABLE 17-5:
TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. 40* 41* 42* Sym TT0H TT0L TT0P Characteristic T0CKI High Pulse Width T0CKI Low Pulse Width T0CKI Period No Prescaler With Prescaler No Prescaler With Prescaler Min 0.5 TCY + 20 10 0.5 TCY + 20 10 Greater of: 20 or TCY + 40 N 0.5 TCY + 20 15 30 0.5 TCY + 20 15 30 Greater of: 30 or TCY + 40 N 60 -- 2 TOSC Typ -- -- -- -- -- Max -- -- -- -- -- Units ns ns ns ns ns N = prescale value (2, 4, ..., 256) Conditions
45*
TT1H
T1CKI High Synchronous, No Prescaler Time Synchronous, with Prescaler Asynchronous T1CKI Low Time Synchronous, No Prescaler Synchronous, with Prescaler Asynchronous
-- -- -- -- -- -- --
-- -- -- -- -- -- --
ns ns ns ns ns ns ns N = prescale value (1, 2, 4, 8)
46*
TT1L
47*
TT1P
T1CKI Input Synchronous Period Asynchronous
-- 32.768 --
-- -- 7 TOSC
ns kHz -- Timers in Sync mode
48 49*
FT1
Timer1 Oscillator Input Frequency Range (oscillator enabled by setting bit T1OSCEN)
TCKEZTMR1 Delay from External Clock Edge to Timer Increment *
These parameters are characterized but not tested. Data in "Typ" column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested.
(c) 2007 Microchip Technology Inc.
DS41262D-page 243
PIC16F631/677/685/687/689/690
FIGURE 17-9: CAPTURE/COMPARE/PWM TIMINGS (ECCP)
CCP1 (Capture mode)
CC01 CC03 Note: Refer to Figure 17-3 for load conditions.
CC02
TABLE 17-6:
CAPTURE/COMPARE/PWM REQUIREMENTS (ECCP)
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. CC01* CC02* CC03* Sym TccL TccH TccP Characteristic CCP1 Input Low Time CCP1 Input High Time CCP1 Input Period No Prescaler With Prescaler No Prescaler With Prescaler Min 0.5TCY + 20 20 0.5TCY + 20 20 3TCY + 40 N Typ -- -- -- -- -- Max -- -- -- -- -- Units ns ns ns ns ns N = prescale value (1, 4 or 16) Conditions
* These parameters are characterized but not tested. Data in "Typ" column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested.
DS41262D-page 244
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 17-7: COMPARATOR SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C 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* 10* Units mV V db ns s Comments Comparator Specifications Param. No. CM01 CM02 CM03 CM04 CM05 * Note 1: Sym VOS VCM CMRR TRT
TMC2COV Comparator Mode Change to Output Valid
These parameters are characterized but not tested. Response time measured with one comparator input at (VDD - 1.5)/2 while the other input transitions from VSS to VDD - 1.5V.
TABLE 17-8:
COMPARATOR VOLTAGE REFERENCE (CVREF) SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C Param No. CV01* CV02* CV03* CV04* Sym CLSB CACC CR CST Characteristics Step Size(2) Absolute Accuracy Unit Resistor Value (R) Settling Time(1) Min -- -- -- -- -- -- Typ VDD/24 VDD/32 -- -- 2k -- Max -- -- 1/4 1/2 -- 10 Units V V LSb LSb s Comments Low Range (VRR = 1) High Range (VRR = 0) Low Range (VRR = 1) High Range (VRR = 0)
* These parameters are characterized but not tested. Data in "Typ" column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Settling time measured while VRR = 1 and VR<3:0> transitions from `0000' to `1111'. 2: See Section 8.10 "Comparator Voltage Reference" for more information.
TABLE 17-9:
VOLTAGE (VR) REFERENCE SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C Min TBD -- -- -- Typ 0.6 150 200 10 Max TBD TBD -- 100* Units V ppm/C V/V s Comments
VR Voltage Reference Specifications Param No. VR01 VR02 VR03 VR04 Symbol VROUT TCVOUT Characteristics VR voltage output Voltage drift temperature coefficient Voltage drift with respect to VDD regulation Settling Time
VROUT/ VDD
TSTABLE
Legend: TBD = To Be Determined * These parameters are characterized but not tested.
(c) 2007 Microchip Technology Inc.
DS41262D-page 245
PIC16F631/677/685/687/689/690
FIGURE 17-10: EUSART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RB7/TX/CK pin RB5/AN11/RX/DT pin 120 Note:
121
121
122
Refer to Figure 17-3 for load conditions.
TABLE 17-10: EUSART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param. No. 120 121 122 Symbol Characteristic Min -- -- -- Max 40 20 20 Units ns ns ns Conditions
TCKH2DTV SYNC XMIT (Master & Slave) Clock high to data-out valid TCKRF Clock out rise time and fall time (Master mode) TDTRF Data-out rise time and fall time
FIGURE 17-11:
EUSART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
RC4/C2OUT/TX/CK pin RC5/RX/DT pin
125
126 Note: Refer to Figure 17-3 for load conditions.
TABLE 17-11: EUSART SYNCHRONOUS RECEIVE REQUIREMENTS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param. No. 125 126 Symbol Characteristic Min Max Units Conditions
TDTV2CKL SYNC RCV (Master & Slave) Data-hold before CK (DT hold time) TCKL2DTL Data-hold after CK (DT hold time)
10 15
-- --
ns ns
DS41262D-page 246
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 17-12:
SS 70 SCK (CKP = 0) 71 72
SPI MASTER MODE TIMING (CKE = 0, SMP = 0)
78
79
SCK (CKP = 1) 79 78
80 SDO MSb 75, 76 SDI MSb In 74 73 Note: Refer to Figure 17-3 for load conditions. bit 6 - - - -1
bit 6 - - - - - -1
LSb
LSb In
FIGURE 17-13:
SS
SPI MASTER MODE TIMING (CKE = 1, SMP = 1)
81 SCK (CKP = 0) 71 73 SCK (CKP = 1) 80 78 72 79
SDO
MSb 75, 76
bit 6 - - - - - -1
LSb
SDI
MSb In 74
bit 6 - - - -1
LSb In
Note: Refer to Figure 17-3 for load conditions.
(c) 2007 Microchip Technology Inc.
DS41262D-page 247
PIC16F631/677/685/687/689/690
FIGURE 17-14:
SS 70 SCK (CKP = 0) 71 72 83
SPI SLAVE MODE TIMING (CKE = 0)
78
79
SCK (CKP = 1) 79 78
80 SDO MSb 75, 76 SDI MSb In 74 73 Note: Refer to Figure 17-3 for load conditions. bit 6 - - - -1
bit 6 - - - - - -1
LSb 77 LSb In
FIGURE 17-15:
SPI SLAVE MODE TIMING (CKE = 1)
82
SS
SCK (CKP = 0)
70 83 71 72
SCK (CKP = 1) 80
SDO
MSb 75, 76
bit 6 - - - - - -1
LSb 77
SDI
MSb In 74
bit 6 - - - -1
LSb In
Note: Refer to Figure 17-3 for load conditions.
DS41262D-page 248
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 17-12: SPI MODE REQUIREMENTS
Param No. 70* 71* 72* 73* 74* 75* 76* 77* 78* 79* 80* 81* 82* 83* Symbol Characteristic Min TCY TCY + 20 TCY + 20 100 100 -- -- -- 10 -- -- -- 3.0-5.5V 2.0-5.5V -- -- Tcy -- 1.5TCY + 40 3.0-5.5V 2.0-5.5V Typ -- -- -- -- -- 10 25 10 -- 10 25 10 -- -- -- -- -- Max Units Conditions -- -- -- -- -- 25 50 25 50 25 50 25 50 145 -- 50 -- ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
TSSL2SCH, SS to SCK or SCK input TSSL2SCL TSCH TSCL SCK input high time (Slave mode) SCK input low time (Slave mode)
TDIV2SCH, Setup time of SDI data input to SCK edge TDIV2SCL TSCH2DIL, TSCL2DIL TDOR TDOF TSSH2DOZ TSCR TSCF Hold time of SDI data input to SCK edge SDO data output rise time SDO data output fall time SS to SDO output high-impedance SCK output rise time (Master mode) SCK output fall time (Master mode) 3.0-5.5V 2.0-5.5V
TSCH2DOV, SDO data output valid after TSCL2DOV SCK edge
TDOV2SCH, SDO data output setup to SCK edge TDOV2SCL TSSL2DOV SDO data output valid after SS edge TSCH2SSH, SS after SCK edge TSCL2SSH
* These parameters are characterized but not tested. Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested.
FIGURE 17-16:
I2CTM BUS START/STOP BITS TIMING
SCL 90 SDA
91 92
93
Start Condition Note: Refer to Figure 17-3 for load conditions.
Stop Condition
(c) 2007 Microchip Technology Inc.
DS41262D-page 249
PIC16F631/677/685/687/689/690
TABLE 17-13: I2CTM BUS START/STOP BITS REQUIREMENTS
Param No. 90* 91* 92* 93 * Symbol TSU:STA THD:STA TSU:STO Characteristic Start condition Setup time Start condition Hold time Stop condition Setup time THD:STO Stop condition Hold 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 Min 4700 600 4000 600 4700 600 4000 600 Typ -- -- -- -- -- -- -- -- Max Units -- -- -- -- -- -- -- -- ns ns ns ns Conditions Only relevant for Repeated Start condition After this period, the first clock pulse is generated
These parameters are characterized but not tested.
FIGURE 17-17:
I2CTM BUS DATA TIMING
103 100 101 102
SCL
90 91
106
107 92
SDA In 110 109 SDA Out Note: Refer to Figure 17-3 for load conditions. 109
DS41262D-page 250
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
TABLE 17-14: I2CTM BUS DATA REQUIREMENTS
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 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode 100 kHz mode 400 kHz mode Min 4.0 0.6 1.5TCY 4.7 1.3 1.5TCY -- 20 + 0.1CB -- 20 + 0.1CB 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 10-400 pF Only relevant for Repeated Start condition After this period the first clock pulse is generated CB is specified to be from 10-400 pF s s Device must operate at a minimum of 1.5 MHz Device must operate at a minimum of 10 MHz Units s s Conditions Device must operate at a minimum of 1.5 MHz Device 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
Start condition hold 100 kHz mode time 400 kHz mode Data input hold time 100 kHz mode 400 kHz mode 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
CB * Note 1: 2:
Bus capacitive loading
These parameters are characterized but not tested. 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. A Fast mode (400 kHz) I2C bus device can be used in a Standard mode (100 kHz) 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.
(c) 2007 Microchip Technology Inc.
DS41262D-page 251
PIC16F631/677/685/687/689/690
TABLE 17-15: A/D CONVERTER (ADC) CHARACTERISTICS:
Standard Operating Conditions (unless otherwise stated) Operating temperature -40C TA +125C Param Sym No. AD01 AD02 AD03 AD04 AD04A AD07 EGN Gain Error Reference Voltage(3) AD06 VREF AD06A AD07 AD08 VAIN ZAIN NR EIL EDL EOFF Characteristic Resolution Integral Error Differential Error Offset Error Min -- -- -- -- -- -- 2.2 2.5 VSS -- Typ -- -- -- -- 1.5 -- -- Max 10 bits 1 1 1 -- 1 -- VDD VREF 10 Units bit LSb VREF = 5.12V LSb No missing codes to 10 bits VREF = 5.12V LSb VREF = 5.12V LSb (PIC16F677 only) LSb VREF = 5.12V V Absolute minimum to ensure 1 LSb accuracy V k Conditions
Full-Scale Range Recommended Impedance of Analog Voltage Source VREF Input Current(3)
-- --
AD09* IREF
10 --
-- --
1000 50
A A
During VAIN acquisition. Based on differential of VHOLD to VAIN. During A/D conversion cycle
* These parameters are characterized but not tested. 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: Total Absolute Error includes integral, differential, offset and gain errors. 2: The A/D conversion result never decreases with an increase in the input voltage and has no missing codes. 3: ADC VREF is from external VREF or VDD pin, whichever is selected as reference input. 4: When ADC is off, it will not consume any current other than leakage current. The power-down current specification includes any such leakage from the ADC module.
DS41262D-page 252
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 17-18: A/D CONVERSION TIMING (NORMAL MODE)
1 TCY 131 130 A/D CLK A/D Data ADRES ADIF GO Sample Note 1: 132 Sampling Stopped 9 8 OLD_DATA 7 6 3 2 1 0 NEW_DATA 1 TCY DONE BSF ADCON0, GO 134 Q4
(TOSC/2)(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.
TABLE 17-16: A/D CONVERSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. 130 130 Sym TAD TAD Characteristic A/D Clock Period A/D Internal RC Oscillator Period Conversion Time (not including Acquisition Time)(1) Acquisition Time Min 1.5 3.0* 3.0* 2.0* 131 TCNV -- Typ -- -- 6.0 4.0 11 Max -- -- 9.0* 6.0* -- Units s s s s TAD Conditions TOSC-based, VREF 2.5V TOSC-based, VREF full range ADCS<1:0> = 11 (RC mode) At VDD = 2.5V At VDD = 5.0V Set GO bit to new data in A/D Result register
132
TACQ
(2)
11.5 --
-- --
s s The minimum time is the amplifier settling time. This may be used if the "new" input voltage has not changed by more than 1 LSb (i.e., 4.1 mV @ 4.096V) from the last sampled voltage (as stored on CHOLD). 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.
5*
134
TGO
Q4 to A/D Clock Start
--
TOSC/2
--
--
* These parameters are characterized but not tested. 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: ADRESH and ADRESL registers may be read on the following TCY cycle. 2: See Table 9-1 for minimum conditions.
(c) 2007 Microchip Technology Inc.
DS41262D-page 253
PIC16F631/677/685/687/689/690
FIGURE 17-19: A/D CONVERSION TIMING (SLEEP MODE)
BSF ADCON0, GO 134 Q4 130 A/D CLK A/D Data ADRES ADIF GO Sample 132 Sampling Stopped 9 8 7 6 3 2 1 0 NEW_DATA 1 TCY DONE
(TOSC/2 + TCY)(1)
131
1 TCY
OLD_DATA
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.
TABLE 17-17: A/D CONVERSION REQUIREMENTS (SLEEP MODE)
Standard Operating Conditions (unless otherwise stated) Operating Temperature -40C TA +125C Param No. 130 Sym TAD Characteristic A/D Internal RC Oscillator Period Conversion Time (not including Acquisition Time)(1) Acquisition Time Min Typ Max Units s s TAD Conditions ADCS<1:0> = 11 (RC mode) At VDD = 2.5V At VDD = 5.0V
3.0* 2.0* --
6.0 4.0 11
9.0* 6.0* --
131
TCNV
132
TACQ
(2)
11.5 --
-- --
s s The minimum time is the amplifier settling time. This may be used if the "new" input voltage has not changed by more than 1 LSb (i.e., 4.1 mV @ 4.096V) from the last sampled voltage (as stored on CHOLD). 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.
5*
134
TGO
Q4 to A/D Clock Start
--
TOSC/2 + TCY
--
--
* These parameters are characterized but not tested. 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: ADRES register may be read on the following TCY cycle. 2: See Table 9-1 for minimum conditions.
DS41262D-page 254
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
18.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES
The graphs and tables provided in this section are for design guidance and are not tested. In some graphs or tables, the data presented are outside specified operating range (i.e., outside specified VDD range). This is for information only and devices are ensured to operate properly only within the specified range. Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore, outside the warranted range.
"Typical" represents the mean of the distribution at 25C. "Maximum" or "minimum" represents (mean + 3) or (mean - 3) respectively, where is a standard deviation, over each temperature range. FIGURE 18-1:
3.5 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
TYPICAL IDD vs. FOSC OVER VDD (EC MODE)
3.0
5.5V 5.0V
2.5
IDD (mA)
2.0
4.0V
1.5
3.0V
1.0
2.0V
0.5
0.0 1 MHz 2 MHz 4 MHz 6 MHz 8 MHz 10 MHz FOSC 12 MHz 14 MHz 16 MHz 18 MHz 20 MHz
(c) 2007 Microchip Technology Inc.
DS41262D-page 255
PIC16F631/677/685/687/689/690
FIGURE 18-2:
4.0 3.5 3.0 2.5 IDD (mA) 4.0V 2.0 1.5 1.0 0.5 0.0 1 MHz 2 MHz 4 MHz 6 MHz 8 MHz 10 MHz FOSC 12 MHz 14 MHz 16 MHz 18 MHz 20 MHz 3.0V Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) 5.5V 5.0V
MAXIMUM IDD vs. FOSC OVER VDD (EC MODE) EC Mode
2.0V
FIGURE 18-3:
4.0 3.5 3.0
TYPICAL IDD vs. FOSC OVER VDD (HS MODE)
Typical IDD vs FOSC Over Vdd HS Mode
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
5.5V 5.0V
2.5 IDD (mA) 2.0 1.5 1.0 0.5 0.0 4 MHz 10 MHz FOSC 16 MHz 4.0V 3.5V 3.0V
4.5V
20 MHz
DS41262D-page 256
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-4: MAXIMUM IDD vs. FOSC OVER VDD (HS MODE)
Maximum IDD vs FOSC Over Vdd HS Mode 5.0 4.5 4.0 3.5 IDD (mA) 3.0 2.5 2.0 1.5 1.0 0.5 0.0 4 MHz 10 MHz FOSC 16 MHz 20 MHz 4.0V 3.5V 3.0V Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) 5.5V 5.0V 4.5V
FIGURE 18-5:
900 800 700 600 IDD (A) 500
TYPICAL IDD vs. VDD OVER FOSC (XT MODE)
XT Mode
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
4 MHz 400 300 1 MHz 200 100 0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 257
PIC16F631/677/685/687/689/690
FIGURE 18-6: MAXIMUM IDD vs. VDD OVER FOSC (XT MODE)
XT Mode 1,400 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
1,200
1,000
IDD (A)
800 4 MHz 600
400
1 MHz
200
0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
FIGURE 18-7:
800 700 600 500 IDD (A) 400 300
TYPICAL IDD vs. VDD OVER FOSC (EXTRC MODE) EXTRC Mode
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
4 MHz
1 MHz 200 100 0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
DS41262D-page 258
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-8:
1,400 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
MAXIMUM IDD vs. VDD OVER FOSC (EXTRC MODE)
EXTRC Mode
1,200
1,000 4 MHz
IDD (A)
800
600
400
1 MHz
200
0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
FIGURE 18-9:
80 70 60 50 IDD (A) 40 30
IDD vs. VDD OVER FOSC (LFINTOSC MODE, 31 kHz)
LFINTOSC Mode, 31KHZ
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
Maximum
Typical 20 10 0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 259
PIC16F631/677/685/687/689/690
FIGURE 18-10:
1,600 1,400 1,200 1,000 IDD (A) 800 3.0V 600 400 200 0 125 kHz 250 kHz 500 kHz 1 MHz FOSC 2 MHz 4 MHz 8 MHz 2.0V Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) 5.5V 5.0V
TYPICAL IDD vs. FOSC OVER VDD (HFINTOSC MODE) HFINTOSC
4.0V
FIGURE 18-11:
2,000 1,800 1,600 1,400 1,200 IDD (A) 1,000
MAXIMUM IDD vs. FOSC OVER VDD (HFINTOSC MODE)
HFINTOSC
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
5.5V 5.0V
4.0V
3.0V 800 600 400 200 0 125 kHz 250 kHz 500 kHz 1 MHz FOSC 2 MHz 4 MHz 8 MHz 2.0V
DS41262D-page 260
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-12:
0.45 0.40 0.35 0.30 IPD (A) 0.25 0.20 0.15 0.10 0.05 0.0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
TYPICAL IPD vs. VDD (SLEEP MODE, ALL PERIPHERALS DISABLED)
Typical (Sleep Mode all Peripherals Disabled)
FIGURE 18-13:
18.0 16.0 14.0
MAXIMUM IPD vs. VDD (SLEEP MODE, ALL PERIPHERALS DISABLED)
Maximum (Sleep Mode all Peripherals Disabled)
Typical: Statistical Mean @25C Maximum: Mean + 3 Case Temp) + 3 Maximum: Mean (Worst (-40C to 125C) Max. 125C
12.0 IPD (A) 10.0 8.0 6.0 4.0 2.0 0.0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5 Max. 85C
(c) 2007 Microchip Technology Inc.
DS41262D-page 261
PIC16F631/677/685/687/689/690
FIGURE 18-14:
180 160 140 120 IPD (A) 100 Typical 80 60 40 20 0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
COMPARATOR IPD vs. VDD (BOTH COMPARATORS ENABLED)
Maximum
FIGURE 18-15:
160
BOR IPD vs. VDD OVER TEMPERATURE
140
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
120
100 IPD (A) Maximum 80 Typical 60
40
20
0 2.5 3.0 3.5 4.0 VDD (V) 4.5 5.0 5.5
DS41262D-page 262
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-16:
3.0 Typical: Statistical Mean @25C Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
TYPICAL WDT IPD vs. VDD OVER TEMPERATURE
Typical
2.5
2.0 IPD (A)
1.5
1.0
0.5
0.0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
FIGURE 18-17:
25.0
MAXIMUM WDT IPD vs. VDD OVER TEMPERATURE
Maximum
20.0 Max. 125C 15.0 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
IPD (A)
10.0
5.0
Max. 85C
0.0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 263
PIC16F631/677/685/687/689/690
FIGURE 18-18:
30 28 26 24 22 Time (ms) 20 Typical 18 16 14 Minimum 12 10 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) Max. (125C) Max. (85C)
WDT PERIOD vs. VDD OVER TEMPERATURE
FIGURE 18-19:
30 28 26
WDT PERIOD vs. TEMPERATURE OVER VDD (5.0V)
Vdd = 5V
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) Maximum
24 22 Time (ms) 20 Typical 18 16 Minimum 14 12 10 -40C 25C Temperature (C) 85C 125C
DS41262D-page 264
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-20:
140 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
CVREF IPD vs. VDD OVER TEMPERATURE (HIGH RANGE)
High Range
120
100 Max. 125C IPD (A) 80 Max. 85C 60 Typical 40
20
0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
FIGURE 18-21:
180 160 140 120
CVREF IPD vs. VDD OVER TEMPERATURE (LOW RANGE)
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
Max. 125C IPD (A) 100 Max. 85C 80 Typical 60 40 20 0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 265
PIC16F631/677/685/687/689/690
FIGURE 18-22: VOL vs. IOL OVER TEMPERATURE (VDD = 3.0V)
(VDD = 3V, -40xC TO 125xC)
0.8 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
0.7
Max. 125C
0.6
0.5 VOL (V)
Max. 85C
0.4
0.3
Typical 25C
0.2 Min. -40C 0.1
0.0 5.0 5.5 6.0 6.5 7.0 7.5 IOL (mA) 8.0 8.5 9.0 9.5 10.0
FIGURE 18-23:
0.45
VOL vs. IOL OVER TEMPERATURE (VDD = 5.0V)
0.40
Typical: Statistical Mean @25C Typical: Statistical Case @25xC Maximum: Mean (Worst Mean Temp) + 3 Maximum: Meas + 3 to 125xC) (-40xC (-40C to 125C)
Max. 125C Max. 85C
0.35
0.30
VOL (V)
0.25 Typ. 25C 0.20
0.15
Min. -40C
0.10
0.05
0.00 5.0 5.5 6.0 6.5 7.0 7.5 IOL (mA) 8.0 8.5 9.0 9.5 10.0
DS41262D-page 266
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-24:
3.5
VOH vs. IOH OVER TEMPERATURE (VDD = 3.0V)
3.0 Max. -40C Typ. 25C
2.5
Min. 125C 2.0 VOH (V) 1.5 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) 1.0 0.5 0.0 0.0 -0.5 -1.0 -1.5 -2.0 IOH (mA) -2.5 -3.0 -3.5 -4.0
FIGURE 18-25:
5.5
VOH vs. IOH OVER TEMPERATURE TO 125xC) (VDD = 5V, -40xC (VDD = 5.0V)
5.0 Max. -40C
Typ. 25C 4.5 VOH (V) Min. 125C
4.0
3.5
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
3.0 0.0 -0.5 -1.0 -1.5 -2.0 -2.5 IOH (mA) -3.0 -3.5 -4.0 -4.5 -5.0
(c) 2007 Microchip Technology Inc.
DS41262D-page 267
PIC16F631/677/685/687/689/690
FIGURE 18-26:
1.7 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C) Max. -40C 1.3 VIN (V) Typ. 25C 1.1 Min. 125C 0.9
TTL INPUT THRESHOLD VIN vs. VDD OVER TEMPERATURE
(TTL Input, -40xC TO 125xC)
1.5
0.7
0.5 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
FIGURE 18-27:
SCHMITT TRIGGER INPUT THRESHOLD VIN vs. VDD OVER TEMPERATURE
(ST Input, -40xC TO 125xC)
4.0 VIH Max. 125C 3.5 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
VIH Min. -40C
3.0
VIN (V)
2.5
2.0 VIL Max. -40C 1.5 VIL Min. 125C
1.0
0.5 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
DS41262D-page 268
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-28:
1000 900 800 Response Time (nS) 700 600 500 400 300 200 100 0 2.0 2.5 VDD (V) 4.0 5.5 Typ. 25C Min. -40C Note: VCM = VDD - 1.5V)/2 V+ input = VCM V- input = Transition from VCM + 100MV to VCM - 20MV Max. 125C
COMPARATOR RESPONSE TIME (RISING EDGE)
531 806
Max. 85C
FIGURE 18-29:
1000 900 800 700 Response Time (nS) 600 500 400 300 200 100 0 Note:
COMPARATOR RESPONSE TIME (FALLING EDGE)
Max. 125C
VCM = VDD - 1.5V)/2 V+ input = VCM V- input = Transition from VCM - 100MV to VCM + 20MV
Max. 85C
Typ. 25C Min. -40C
2.0
2.5 VDD (V)
4.0
5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 269
PIC16F631/677/685/687/689/690
FIGURE 18-30:
45,000 40,000 35,000 30,000 Frequency (Hz) 25,000 20,000 15,000 10,000 5,000 0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5 Min. 85C Min. 125C Typ. 25C
LFINTOSC FREQUENCY vs. VDD OVER TEMPERATURE (31 kHz)
LFINTOSC 31Khz
Max. -40C
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
FIGURE 18-31:
8
ADC CLOCK PERIOD vs. VDD OVER TEMPERATURE
125C 6 85C
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
Time (s)
4
25C
-40C 2
0 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
DS41262D-page 270
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-32:
16 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
TYPICAL HFINTOSC START-UP TIMES vs. VDD OVER TEMPERATURE
14 85C 12 25C 10 Time (s) -40C 8
6
4
2
0 2.0
2.5
3.0
3.5 VDD (V)
4.0
4.5
5.0
5.5
FIGURE 18-33:
25
MAXIMUM HFINTOSC START-UP TIMES vs. VDD OVER TEMPERATURE
-40C to +85C
20
Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
Time (s)
15 85C 25C 10 -40C
5
0 2.0
2.5
3.0
3.5 VDD (V)
4.0
4.5
5.0
5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 271
PIC16F631/677/685/687/689/690
FIGURE 18-34:
10 9 8 7 85C Time (s) 6 25C 5 -40C 4 3 2 1 0 2.0 Typical: Statistical Mean @25C Maximum: Mean (Worst Case Temp) + 3 (-40C to 125C)
MINIMUM HFINTOSC START-UP TIMES vs. VDD OVER TEMPERATURE
-40C to +85C
2.5
3.0
3.5 VDD (V)
4.0
4.5
5.0
5.5
FIGURE 18-35:
5 4 3 Change from Calibration (%) 2 1 0 -1 -2 -3 -4 -5 2.0
TYPICAL HFINTOSC FREQUENCY CHANGE vs. VDD (25C)
2.5
3.0
3.5 VDD (V)
4.0
4.5
5.0
5.5
DS41262D-page 272
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
FIGURE 18-36:
5 4 3 Change from Calibration (%) 2 1 0 -1 -2 -3 -4 -5 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
TYPICAL HFINTOSC FREQUENCY CHANGE OVER DEVICE VDD (85C)
FIGURE 18-37:
5 4 3 Change from Calibration (%) 2 1 0 -1 -2 -3 -4 -5 2.0
TYPICAL HFINTOSC FREQUENCY CHANGE vs. VDD (125C)
2.5
3.0
3.5 VDD (V)
4.0
4.5
5.0
5.5
(c) 2007 Microchip Technology Inc.
DS41262D-page 273
PIC16F631/677/685/687/689/690
FIGURE 18-38:
5 4 3 Change from Calibration (%) 2 1 0 -1 -2 -3 -4 -5 2.0 2.5 3.0 3.5 VDD (V) 4.0 4.5 5.0 5.5
TYPICAL HFINTOSC FREQUENCY CHANGE vs. VDD (-40C)
DS41262D-page 274
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
19.0
19.1
PACKAGING INFORMATION
Package Marking Information
20-Lead PDIP
XXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXX YYWWNNN
Example
PIC16F685-I/P e3 0510017
20-Lead SOIC (7.50 mm)
XXXXXXXXXXXXXX XXXXXXXXXXXXXX XXXXXXXXXXXXXX YYWWNNN
Example
PIC16F685-I /SO e3 0510017
20-Lead SSOP XXXXXXXXXXX XXXXXXXXXXX YYWWNNN
Example PIC16F687 -I/SS e3 0510017
20-Lead QFN
Example
XXXXXX XXXXXX YWWNNN
16F690 -I/ML e3 510017
Legend: XX...X Y YY WW NNN
e3
*
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 Pb-free JEDEC designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package.
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.
(c) 2007 Microchip Technology Inc.
DS41262D-page 275
PIC16F631/677/685/687/689/690
19.2 Package Details
The following sections give the technical details of the packages.
20-Lead Plastic Dual In-Line (P) - 300 mil Body [PDIP]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging
N
NOTE 1
E1
1
2
3 D E
A
A2 L A1 b1 b e
Units Dimension Limits Number of Pins Pitch Top to Seating Plane Molded Package Thickness Base to Seating Plane Shoulder to Shoulder Width Molded Package Width Overall Length Tip to Seating Plane Lead Thickness Upper Lead Width Lower Lead Width Overall Row Spacing N e A A2 A1 E E1 D L c b1 b eB - .115 .015 .300 .240 .980 .115 .008 .045 .014 - MIN INCHES NOM 20 .100 BSC - .130 - .310 .250 1.030 .130 .010 .060 .018 - .210 .195 - .325 .280 1.060 .150 .015 .070 .022 MAX
c
eB
.430 Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Significant Characteristic. 3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" per side. 4. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. Microchip Technology Drawing C04-019B
DS41262D-page 276
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
20-Lead Plastic Small Outline (SO) - Wide, 7.50 mm Body [SOIC]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging
D N
E E1 NOTE 1 123 b h A A2 c e h
L A1 L1
Units Dimension Limits Number of Pins Pitch Overall Height Molded Package Thickness Standoff Overall Width Molded Package Width Overall Length Chamfer (optional) Foot Length Footprint Foot Angle Lead Thickness Lead Width Mold Draft Angle Top Mold Draft Angle Bottom N e A A2 A1 E E1 D h L L1 c b 0 0.20 0.31 5 5 0.25 0.40 - 2.05 0.10 MIN
MILLIMETERS NOM 20 1.27 BSC - - - 10.30 BSC 7.50 BSC 12.80 BSC - - 1.40 REF - - - - - 8 0.33 0.51 15 0.75 1.27 2.65 - 0.30 MAX
15 Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Significant Characteristic. 3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side. 4. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. Microchip Technology Drawing C04-094B
(c) 2007 Microchip Technology Inc.
DS41262D-page 277
PIC16F631/677/685/687/689/690
20-Lead Plastic Shrink Small Outline (SS) - 5.30 mm Body [SSOP]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging
D N
E E1
NOTE 1 12 b e
A
A2
c
A1 L1
Units Dimension Limits Number of Pins Pitch Overall Height Molded Package Thickness Standoff Overall Width Molded Package Width Overall Length Foot Length Footprint Lead Thickness Foot Angle Lead Width N e A A2 A1 E E1 D L L1 c b 0.09 0 0.22 - 1.65 0.05 7.40 5.00 6.90 0.55 MIN MILLIMETERS NOM 20 0.65 BSC - 1.75 - 7.80 5.30 7.20 0.75 1.25 REF - 4 - 0.25 8 0.38 2.00 1.85 - 8.20 5.60 7.50 0.95 MAX
L
Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.20 mm per side. 3. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. Microchip Technology Drawing C04-072B
DS41262D-page 278
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
20-Lead Plastic Quad Flat, No Lead Package (ML) - 4x4x0.9 mm Body [QFN]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging
D EXPOSED PAD D2
e E2 2 1 E 2 1 K N TOP VIEW NOTE 1 N BOTTOM VIEW L b
A A3 A1
Units Dimension Limits Number of Pins Pitch Overall Height Standoff Contact Thickness Overall Width Exposed Pad Width Overall Length Exposed Pad Length Contact Width Contact Length Contact-to-Exposed Pad N e A A1 A3 E E2 D D2 b L K 2.60 0.18 0.30 0.20 2.60 0.80 0.00 MIN MILLIMETERS NOM 20 0.50 BSC 0.90 0.02 0.20 REF 4.00 BSC 2.70 4.00 BSC 2.70 0.25 0.40 - 2.80 0.30 0.50 - 2.80 1.00 0.05 MAX
Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Package is saw singulated. 3. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. Microchip Technology Drawing C04-126B
(c) 2007 Microchip Technology Inc.
DS41262D-page 279
PIC16F631/677/685/687/689/690
NOTES:
DS41262D-page 280
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
APPENDIX A: DATA SHEET REVISION HISTORY APPENDIX B: MIGRATING FROM OTHER PIC(R) DEVICES
Revision A (March 2005)
This is a new data sheet.
This discusses some of the issues in migrating from other PIC devices to the PIC16F6XX Family of devices.
Revision B (May 2006)
Added 631/677 part numbers; Added pin summary tables after pin diagrams; Incorporated Golden Chapters.
B.1
PIC16F676 to PIC16F685
FEATURE COMPARISON
PIC16F676 20 MHz 1024 64 10-bit 128 1/1 8 Y RA0/1/2/4/5 PIC16F685 20 MHz 4096 128 10-bit 256 2/1 8 Y RA0/1/2/4/5, MCLR 2 Y Y Y Y 31 kHz-8 MHz Y Feature
TABLE B-1:
Max Operating Speed Max Program Memory (Words) SRAM (bytes) A/D Resolution Data EEPROM (Bytes) Timers (8/16-bit) Oscillator Modes Brown-out Reset Internal Pull-ups
Revision C (July 2006)
Revised Section 4.2.1, ANSEL and ANSELH Registers; Register 4-3, ANSEL Analog Select; Added Register 4-4, ANSELH Analog Select High; Section 11.3.2, Revised CCP1<1:0> to DC1B<1:0>; Section 11.3.7, Number 4 - Revised CCP1 to DC1B; Figure 115, Revised CCP1 to DC1B; Table 11-4, Revised P1M to P1M<1:0>; Section 12.3.1, Revised Paragraph 3; Revised Note 2; Revised Figure 12-6 Title.
Revision D (February 2007)
Removed Preliminary status; Changed PICmicro to PIC; Replaced Dev. Tool Section; Replaced Package Drawings.
Interrupt-on-change Comparator ECCP+ Ultra Low-Power Wake-up Extended WDT Software Control Option of WDT/BOR INTOSC Frequencies Clock Switching Note:
RA0/1/2/3/4/5 RA0/1/2/3/4/5 1 N N N N 4 MHz N
This device has been designed to perform to the parameters of its data sheet. It has been tested to an electrical specification designed to determine its conformance with these parameters. Due to process differences in the manufacture of this device, this device may have different performance characteristics than its earlier version. These differences may cause this device to perform differently in your application than the earlier version of this device.
(c) 2007 Microchip Technology Inc.
DS41262D-page 281
PIC16F631/677/685/687/689/690
NOTES:
DS41262D-page 282
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
INDEX
A
A/D Specifications............................................ 252, 253, 254 Absolute Maximum Ratings .............................................. 227 AC Characteristics Industrial and Extended ............................................ 238 Load Conditions ........................................................ 237 ACK pulse ......................................................................... 184 ADC .................................................................................. 107 Acquisition Requirements ......................................... 116 Associated registers.................................................. 118 Block Diagram........................................................... 107 Calculating Acquisition Time..................................... 116 Channel Selection..................................................... 108 Configuration............................................................. 108 Configuring Interrupt ................................................. 111 Conversion Clock...................................................... 108 Conversion Procedure .............................................. 111 Internal Sampling Switch (RSS) Impedance.............. 116 Interrupts................................................................... 109 Operation .................................................................. 111 Operation During Sleep ............................................ 111 Port Configuration ..................................................... 108 Reference Voltage (VREF)......................................... 108 Result Formatting...................................................... 110 Source Impedance.................................................... 116 Special Event Trigger................................................ 111 Starting an A/D Conversion ...................................... 110 ADCON0 Register............................................................. 113 ADCON1 Register............................................................. 114 ADRESH Register (ADFM = 0) ......................................... 115 ADRESH Register (ADFM = 1) ......................................... 115 ADRESL Register (ADFM = 0).......................................... 115 ADRESL Register (ADFM = 1).......................................... 115 Analog Input Connection Considerations.......................... 100 Analog-to-Digital Converter. See ADC ANSEL Register .................................................................. 61 ANSELH Register ............................................................... 61 Assembler MPASM Assembler................................................... 224 PIC16F685 ................................................................. 11 PIC16F687/689 .......................................................... 12 PIC16F690 ................................................................. 13 PWM (Enhanced) ..................................................... 133 RA0 Pins..................................................................... 64 RA1 Pins..................................................................... 65 RA2 Pin ...................................................................... 65 RA3 Pin ...................................................................... 66 RA4 Pin ...................................................................... 66 RA5 Pin ...................................................................... 67 RB4 Pin ...................................................................... 71 RB5 Pin ...................................................................... 72 RB6 Pin ...................................................................... 73 RB7 Pin ...................................................................... 74 RC0 and RC1 Pins ..................................................... 77 RC2 and RC3 Pins ..................................................... 77 RC4 Pin ...................................................................... 78 RC5 Pin ...................................................................... 78 RC6 Pin ...................................................................... 79 RC7 Pin ...................................................................... 79 Resonator Operation .................................................. 50 SSP (I2C Mode)........................................................ 184 SSP (SPI Mode) ....................................................... 175 Timer1 ........................................................................ 84 Timer2 ........................................................................ 91 TMR0/WDT Prescaler ................................................ 81 Watchdog Timer (WDT)............................................ 208 Break Character (12-bit) Transmit and Receive ............... 167 Brown-out Reset (BOR).................................................... 198 Associated ................................................................ 199 Specifications ........................................................... 242 Timing and Characteristics ....................................... 241
C
C Compilers MPLAB C18.............................................................. 224 MPLAB C30.............................................................. 224 Capture Module. See Enhanced Capture/Compare/ PWM(ECCP) Capture/Compare/PWM (CCP) Associated registers w/ Capture/Compare/PWM ..... 148 Capture Mode........................................................... 128 CCPx Pin Configuration............................................ 128 Compare Mode......................................................... 129 CCPx Pin Configuration.................................... 129 Software Interrupt Mode ........................... 128, 129 Special Event Trigger ....................................... 129 Timer1 Mode Selection............................. 128, 129 Prescaler .................................................................. 128 PWM Mode............................................................... 130 Duty Cycle ........................................................ 131 Effects of Reset ................................................ 132 Example PWM Frequencies and Resolutions, 20 MHZ ................................ 131 Example PWM Frequencies and Resolutions, 8 MHz .................................. 131 Operation in Sleep Mode.................................. 132 Setup for Operation .......................................... 132 System Clock Frequency Changes .................. 132 PWM Period ............................................................. 131 Setup for PWM Operation ........................................ 132 CCPxCON (Enhanced) Register ...................................... 127 CKE bit ............................................................................. 176 CKP bit ............................................................................. 177
B
BAUDCTL Register ........................................................... 160 BF bit................................................................................. 176 Block Diagrams (CCP) Capture Mode Operation ............................... 128 ADC .......................................................................... 107 ADC Transfer Function ............................................. 117 Analog Input Model ........................................... 100, 117 CCP PWM................................................................. 130 Clock Source............................................................... 47 Comparator C1 ........................................................... 94 Comparator C2 ........................................................... 94 Compare ................................................................... 129 Crystal Operation ........................................................ 50 EUSART Receive ..................................................... 150 EUSART Transmit .................................................... 149 External RC Mode....................................................... 51 Fail-Safe Clock Monitor (FSCM) ................................. 57 In-Circuit Serial Programming Connections.............. 212 Interrupt Logic ........................................................... 205 On-Chip Reset Circuit ............................................... 196 PIC16F631.................................................................... 9 PIC16F677.................................................................. 10
(c) 2007 Microchip Technology Inc.
DS41262D-page 283
PIC16F631/677/685/687/689/690
Clock Accuracy with Asynchronous Operation ................. 158 Clock Sources External Modes ........................................................... 49 EC ....................................................................... 49 HS ....................................................................... 50 LP........................................................................ 50 OST..................................................................... 49 RC....................................................................... 51 XT ....................................................................... 50 Internal Modes ............................................................ 51 Frequency Selection ........................................... 53 HFINTOSC.......................................................... 51 HFINTOSC/LFINTOSC Switch Timing ............... 53 INTOSC .............................................................. 51 INTOSCIO........................................................... 51 LFINTOSC .......................................................... 53 Clock Switching................................................................... 55 CM1CON0 Register ............................................................ 98 CM2CON0 Register ............................................................ 99 CM2CON1 Register .......................................................... 101 Code Examples A/D Conversion ......................................................... 112 Assigning Prescaler to Timer0 .................................... 82 Assigning Prescaler to WDT ....................................... 82 Changing Between Capture Prescalers .................... 128 Indirect Addressing ..................................................... 44 Initializing PORTA ....................................................... 59 Initializing PORTB ....................................................... 69 Initializing PORTC....................................................... 76 Loading the SSPBUF (SSPSR) Register .................. 178 Saving STATUS and W Registers in RAM ............... 207 Ultra Low-Power Wake-up Initialization ...................... 63 Write Verify ............................................................... 125 Code Protection ................................................................ 211 Comparator C2OUT as T1 Gate ................................................... 101 Operation .................................................................... 93 Operation During Sleep .............................................. 97 Response Time ........................................................... 95 Synchronizing COUT w/Timer1 ................................ 101 Comparator Module ............................................................ 93 Associated registers.................................................. 106 C1 Output State Versus Input Conditions ................... 95 Comparator Voltage Reference (CVREF) Response Time ........................................................... 95 Comparator Voltage Reference (CVREF) .......................... 104 Effects of a Reset........................................................ 97 Specifications ............................................................ 245 Comparators C2OUT as T1 Gate ..................................................... 85 Effects of a Reset........................................................ 97 Specifications ............................................................ 245 Compare Module. See Enhanced Capture/ Compare/PWM (ECCP) CONFIG Register.............................................................. 195 Configuration Bits.............................................................. 194 CPU Features ................................................................... 193 Customer Change Notification Service ............................. 289 Customer Notification Service........................................... 289 Customer Support ............................................................. 289 Reading .................................................................... 122 Writing ...................................................................... 122 Data Memory ...................................................................... 26 Data/Address bit (D/A)...................................................... 176 DC Characteristics Extended .................................................................. 232 Extended and Industrial ............................................ 234 Industrial ................................................................... 230 Industrial and Extended ............................................ 229 Development Support ....................................................... 223 Device Overview................................................................... 9
E
ECCP. See Enhanced Capture/Compare/PWM ECCPAS Register............................................................. 141 EEADR Register ............................................................... 120 EEADR Registers ............................................................. 119 EEADRH Registers........................................................... 119 EECON1 Register..................................................... 119, 121 EECON2 Register............................................................. 119 EEDAT Register ............................................................... 120 EEDATH Register............................................................. 120 EEPROM Data Memory Avoiding Spurious Write ........................................... 125 Write Verify ............................................................... 125 Effects of Reset PWM mode ............................................................... 132 Electrical Specifications .................................................... 227 Enhanced Capture/Compare/PWM .................................. 127 Enhanced Capture/Compare/PWM (ECCP) Enhanced PWM Mode.............................................. 133 Auto-Restart ..................................................... 142 Auto-shutdown.................................................. 141 Direction Change in Full-Bridge Output Mode.. 139 Full-Bridge Application...................................... 137 Full-Bridge Mode .............................................. 137 Half-Bridge Application ..................................... 136 Half-Bridge Application Examples .................... 143 Half-Bridge Mode.............................................. 136 Output Relationships (Active-High and Active-Low)............................................... 134 Output Relationships Diagram.......................... 135 Programmable Dead Band Delay..................... 143 Shoot-through Current ...................................... 143 Start-up Considerations .................................... 140 Specifications ........................................................... 244 Timer Resources ...................................................... 127 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) .............................. 149 Errata .................................................................................... 8 EUSART ........................................................................... 149 Associated Registers Baud Rate Generator ....................................... 161 Asynchronous Mode ................................................. 151 12-bit Break Transmit and Receive .................. 167 Associated Registers Receive .................................................... 157 Transmit.................................................... 153 Auto-Wake-up on Break ................................... 166 Baud Rate Generator (BRG) ............................ 161 Clock Accuracy................................................. 158 Receiver ........................................................... 154 Setting up 9-bit Mode with Address Detect ...... 156 Transmitter ....................................................... 151 Baud Rate Generator (BRG) Auto Baud Rate Detect..................................... 165
D
D/A bit ............................................................................... 176 Data EEPROM Memory .................................................... 119 Associated Registers ................................................ 126 Code Protection ........................................................ 125
DS41262D-page 284
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
Baud Rate Error, Calculating ............................ 161 Baud Rates, Asynchronous Modes .................. 162 Formulas ........................................................... 161 High Baud Rate Select (BRGH Bit) .................. 161 Synchronous Master Mode ....................................... 169 Associated Registers Receive..................................................... 172 Transmit.................................................... 170 Reception.......................................................... 171 Requirements, Synchronous Receive .............. 246 Requirements, Synchronous Transmission ...... 246 Timing Diagram, Synchronous Receive ........... 246 Timing Diagram, Synchronous Transmission ... 246 Transmission .................................................... 169 Synchronous Slave Mode ......................................... 173 Associated Registers Receive..................................................... 174 Transmit.................................................... 173 Reception.......................................................... 174 Transmission .................................................... 173 GOTO ....................................................................... 217 INCF ......................................................................... 217 INCFSZ..................................................................... 217 IORLW ...................................................................... 217 IORWF...................................................................... 217 MOVF ....................................................................... 218 MOVLW .................................................................... 218 MOVWF.................................................................... 218 NOP.......................................................................... 218 RETFIE..................................................................... 219 RETLW ..................................................................... 219 RETURN................................................................... 219 RLF........................................................................... 220 RRF .......................................................................... 220 SLEEP ...................................................................... 220 SUBLW..................................................................... 220 SUBWF..................................................................... 221 SWAPF..................................................................... 221 XORLW .................................................................... 221 XORWF .................................................................... 221 Summary Table ........................................................ 214 INTCON Register................................................................ 38 Inter-Integrated Circuit (I2C). See I2C Mode Internal Oscillator Block INTOSC Specifications ................................................... 239 Internal Sampling Switch (RSS) Impedance ..................... 116 Internet Address ............................................................... 289 Interrupts .......................................................................... 204 ADC .......................................................................... 111 Associated Registers................................................ 206 Context Saving ......................................................... 207 Interrupt-on-Change ................................................... 60 Interrupt-on-change .................................................... 69 PORTA/PORTB Interrupt-on-Change ...................... 205 RA2/INT.................................................................... 204 TMR0........................................................................ 205 TMR1.......................................................................... 86 INTOSC Specifications ..................................................... 239 IOCA Register..................................................................... 62 IOCB Register..................................................................... 70
F
Fail-Safe Clock Monitor....................................................... 57 Fail-Safe Condition Clearing ....................................... 57 Fail-Safe Detection ..................................................... 57 Fail-Safe Operation..................................................... 57 Reset or Wake-up from Sleep..................................... 57 Firmware Instructions........................................................ 213 Flash Program Memory .................................................... 119 Fuses. See Configuration Bits
G
General Purpose Register File............................................ 26
I
I2C Mode Addressing ................................................................ 185 Associated Registers ................................................ 192 Master Mode ............................................................. 191 Mode Selection ......................................................... 184 Multi-Master Mode .................................................... 191 Operation .................................................................. 184 Reception.................................................................. 186 Slave Mode SCL and SDA pins ............................................ 184 Transmission............................................................. 189 ID Locations ...................................................................... 211 In-Circuit Serial Programming (ICSP) ............................... 211 Indirect Addressing, INDF and FSR registers ..................... 44 Instruction Format ............................................................. 213 Instruction Set ................................................................... 213 ADDLW ..................................................................... 215 ADDWF..................................................................... 215 ANDLW ..................................................................... 215 ANDWF..................................................................... 215 BCF........................................................................... 215 BSF ........................................................................... 215 BTFSC ...................................................................... 215 BTFSS ...................................................................... 216 CALL ......................................................................... 216 CLRF......................................................................... 216 CLRW ....................................................................... 216 CLRWDT................................................................... 216 COMF ....................................................................... 216 DECF ........................................................................ 216 DECFSZ.................................................................... 217
L
Load Conditions................................................................ 237
M
MCLR ............................................................................... 197 Internal...................................................................... 197 Memory Organization ......................................................... 25 Data ............................................................................ 26 Program...................................................................... 25 Microchip Internet Web Site.............................................. 289 Migrating from other PIC Devices..................................... 281 MPLAB ASM30 Assembler, Linker, Librarian ................... 224 MPLAB ICD 2 In-Circuit Debugger ................................... 225 MPLAB ICE 2000 High-Performance Universal In-Circuit Emulator.................................................... 225 MPLAB ICE 4000 High-Performance Universal In-Circuit Emulator.................................................... 225 MPLAB Integrated Development Environment Software.. 223 MPLAB PM3 Device Programmer .................................... 225 MPLINK Object Linker/MPLIB Object Librarian ................ 224
(c) 2007 Microchip Technology Inc.
DS41262D-page 285
PIC16F631/677/685/687/689/690
O
OPCODE Field Descriptions ............................................. 213 OPTION Register .......................................................... 37, 83 OSCCON Register .............................................................. 48 Oscillator Associated registers.............................................. 58, 89 Oscillator Module ................................................................ 47 EC ............................................................................... 47 HFINTOSC.................................................................. 47 HS ............................................................................... 47 INTOSC ...................................................................... 47 INTOSCIO................................................................... 47 LFINTOSC .................................................................. 47 LP................................................................................ 47 RC ............................................................................... 47 RCIO ........................................................................... 47 XT ............................................................................... 47 Oscillator Parameters........................................................ 239 Oscillator Specifications .................................................... 238 Oscillator Start-up Timer (OST) Specifications ............................................................ 242 Oscillator Switching Fail-Safe Clock Monitor............................................... 57 Two-Speed Clock Start-up .......................................... 55 OSCTUNE Register ............................................................ 52 Interrupt-on-change .................................................... 69 Pin Descriptions and Diagrams .................................. 71 RB4............................................................................. 71 RB5............................................................................. 72 RB6............................................................................. 73 RB7............................................................................. 74 Registers .................................................................... 69 PORTB Register ................................................................. 69 PORTC ............................................................................... 76 Associated registers ................................................... 80 P1A/P1B/P1C/P1D.See Enhanced Capture/ Compare/PWM+ (ECCP+) ................................. 76 RC0 ............................................................................ 77 RC1 ............................................................................ 77 RC2 ............................................................................ 77 RC3 ............................................................................ 77 RC4 ............................................................................ 78 RC5 ............................................................................ 78 RC6 ............................................................................ 79 RC7 ............................................................................ 79 Registers .................................................................... 76 Specifications ........................................................... 240 PORTC Register................................................................. 76 Power-Down Mode (Sleep)............................................... 210 Power-on Reset (POR)..................................................... 197 Power-up Timer (PWRT) .................................................. 197 Specifications ........................................................... 242 Prescaler Shared WDT/Timer0................................................... 82 Switching Prescaler Assignment ................................ 82 Program Memory ................................................................ 25 Map and Stack...................................................... 25, 26 Programming, Device Instructions .................................... 213 PSTRCON Register.......................................................... 145 Pulse Steering .................................................................. 145 PWM (ECCP Module) Pulse Steering .......................................................... 145 Steering Synchronization.......................................... 147 PWM Mode. See Enhanced Capture/Compare/PWM ...... 133 PWMxCON Register ......................................................... 144
P
P (Stop) bit ........................................................................ 176 P1A/P1B/P1C/P1D.See Enhanced Capture/ Compare/PWM (ECCP) ............................................ 133 Packaging ......................................................................... 275 Marking ..................................................................... 275 PDIP Details.............................................................. 276 PCL and PCLATH ............................................................... 44 Stack ........................................................................... 44 PCON Register ........................................................... 43, 199 PICkit 2 Development Programmer .................................. 226 PICSTART Plus Development Programmer ..................... 226 PIE1 Register ...................................................................... 39 PIE2 Register ...................................................................... 40 Pin Diagram ...................................................... 2, 3, 4, 5, 6, 7 PIR1 Register...................................................................... 41 PIR2 Register...................................................................... 42 PORTA Additional Pin Functions ............................................. 60 ANSEL Register.................................................. 60 ANSELH Register ............................................... 60 Interrupt-on-Change............................................ 60 Ultra Low-Power Wake-up ............................ 60, 63 Weak Pull-Up ...................................................... 60 Associated Registers .................................................. 68 Pin Descriptions and Diagrams................................... 64 RA0 ............................................................................. 64 RA1 ............................................................................. 65 RA2 ............................................................................. 65 RA3 ............................................................................. 66 RA4 ............................................................................. 66 RA5 ............................................................................. 67 Registers ..................................................................... 59 Specifications ............................................................ 240 PORTA Register ................................................................. 59 PORTB Additional Pin Functions ............................................. 69 Weak Pull-Up ...................................................... 69 Associated Registers .................................................. 75
R
R/W bit .............................................................................. 176 RCREG............................................................................. 156 RCSTA Register ............................................................... 159 Reader Response............................................................. 290 Read-Modify-Write Operations ......................................... 213 Receive Overflow Indicator bit (SSPOV) .......................... 177 Register RCREG Register ...................................................... 165 Registers ADCON0 (ADC Control 0) ........................................ 113 ADCON1 (ADC Control 1) ........................................ 114 ADRESH (ADC Result High) with ADFM = 0) .......... 115 ADRESH (ADC Result High) with ADFM = 1) .......... 115 ADRESL (ADC Result Low) with ADFM = 0)............ 115 ADRESL (ADC Result Low) with ADFM = 1)............ 115 ANSEL (Analog Select) .............................................. 61 ANSELH (Analog Select High) ................................... 61 BAUDCTL (Baud Rate Control) ................................ 160 CCPxCON (Enhanced CCPx Control)...................... 127 CM1CON0 (C1 Control).............................................. 98 CM2CON0 (C2 Control).............................................. 99 CM2CON1 (C2 Control)............................................ 101 CONFIG (Configuration Word) ................................. 195 ECCPAS (Enhanced CCP Auto-shutdown Control) . 141
DS41262D-page 286
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
EEADR (EEPROM Address) .................................... 120 EECON1 (EEPROM Control 1)................................. 121 EEDAT (EEPROM Data) .......................................... 120 EEDATH (EEPROM Data)........................................ 120 INTCON (Interrupt Control)......................................... 38 IOCA (Interrupt-on-Change PORTA) .......................... 62 IOCB (Interrupt-on-Change PORTB) .......................... 70 OPTION_REG (OPTION) ..................................... 37, 83 OSCCON (Oscillator Control) ..................................... 48 OSCTUNE (Oscillator Tuning) .................................... 52 PCON (Power Control Register) ................................. 43 PCON (Power Control) ............................................. 199 PIE1 (Peripheral Interrupt Enable 1)........................... 39 PIE2 (Peripheral Interrupt Enable 2)........................... 40 PIR1 (Peripheral Interrupt Register 1) ........................ 41 PIR2 (Peripheral Interrupt Request 2) ........................ 42 PORTA........................................................................ 59 PORTB........................................................................ 69 PORTC ....................................................................... 76 PSTRCON (Pulse Steering Control) ......................... 145 PWMxCON (Enhanced PWM Control) ..................... 144 RCSTA (Receive Status and Control)....................... 159 Reset Values............................................................. 201 Reset Values (special registers) ............................... 203 Special Function Register Map PIC16F677.......................................................... 28 PIC16F685.................................................... 27, 29 PIC16F687/689................................................... 30 PIC16F690.......................................................... 31 Special Function Registers ......................................... 26 Special Register Summary Bank 0................................................................. 32 Bank 1................................................................. 33 Bank 2................................................................. 34 Bank 3................................................................. 35 SRCON (SR Latch Control) ...................................... 103 SSPCON (Sync Serial Port Control) Register........... 177 SSPMSK (SSP Mask)............................................... 187 SSPSTAT (Sync Serial Port Status) Register........... 176 STATUS...................................................................... 36 T1CON........................................................................ 88 T2CON........................................................................ 92 TRISA (Tri-State PORTA)........................................... 59 TRISB (Tri-State PORTB)........................................... 70 TRISC (Tri-State PORTC) .......................................... 76 TXSTA (Transmit Status and Control) ...................... 158 VRCON (Voltage Reference Control) ....................... 106 WDTCON (Watchdog Timer Control) ....................... 209 WPUA (Weak Pull-Up PORTA) .................................. 62 WPUB (Weak Pull-up PORTB) ................................... 70 Reset................................................................................. 196 Revision History ................................................................ 281 SPI Mode .................................................................. 175, 181 Associated Registers................................................ 183 Bus Mode Compatibility ............................................ 183 Effects of a Reset ..................................................... 183 Enabling SPI I/O ....................................................... 179 Master Mode............................................................. 180 Master/Slave Connection ......................................... 179 Serial Clock (SCK pin) .............................................. 175 Serial Data In (SDI pin)............................................. 175 Serial Data Out (SDO pin) ........................................ 175 Slave Select.............................................................. 175 Slave Select Synchronization ................................... 181 Sleep Operation........................................................ 183 SPI Clock.................................................................. 180 Typical Connection ................................................... 179 SRCON Register .............................................................. 103 SSP Overview SPI Master/Slave Connection................................... 179 SSP I2C Operation ........................................................... 184 Slave Mode............................................................... 184 SSP Module Clock Synchronization and the CKP Bit ................... 191 SPI Master Mode...................................................... 180 SPI Slave Mode........................................................ 181 SSPBUF ................................................................... 180 SSPSR ..................................................................... 180 SSPCON Register ............................................................ 177 SSPEN bit......................................................................... 177 SSPM bits ......................................................................... 177 SSPMSK Register ............................................................ 187 SSPOV bit ........................................................................ 177 SSPSTAT Register ........................................................... 176 STATUS Register ............................................................... 36 Synchronous Serial Port Enable bit (SSPEN) .................. 177 Synchronous Serial Port Mode Select bits (SSPM).......... 177 Synchronous Serial Port. See SSP
T
T1CON Register ................................................................. 88 T2CON Register ................................................................. 92 Thermal Considerations.................................................... 236 Time-out Sequence .......................................................... 199 Timer0 ................................................................................ 81 Associated Registers.................................................. 83 External Clock ............................................................ 82 Interrupt ...................................................................... 83 Operation.............................................................. 81, 84 Specifications ........................................................... 243 T0CKI ......................................................................... 82 Timer1 ................................................................................ 84 Associated registers ................................................... 89 Asynchronous Counter Mode ..................................... 85 Reading and Writing ........................................... 85 Interrupt ...................................................................... 86 Modes of Operation .................................................... 84 Operation During Sleep .............................................. 86 Oscillator..................................................................... 85 Prescaler .................................................................... 85 Specifications ........................................................... 243 Timer1 Gate Inverting Gate ..................................................... 86 Selecting Source ........................................ 85, 101 Synchronizing COUT w/Timer1 ........................ 101 TMR1H Register......................................................... 84 TMR1L Register ......................................................... 84
S
S (Start) bit ........................................................................ 176 Shoot-through Current ...................................................... 143 Slave Select Synchronization ........................................... 181 Sleep ................................................................................. 210 Wake-up.................................................................... 210 Wake-up Using Interrupts ......................................... 210 SMP bit ............................................................................. 176 Software Simulator (MPLAB SIM)..................................... 224 SPBRG ............................................................................. 161 SPBRGH ........................................................................... 161 Special Event Trigger........................................................ 111 Special Function Registers ................................................. 26
(c) 2007 Microchip Technology Inc.
DS41262D-page 287
PIC16F631/677/685/687/689/690
Timer2 Associated registers.................................................... 92 Timers Timer1 T1CON................................................................ 88 Timer2 T2CON................................................................ 92 Timing Diagrams A/D Conversion ......................................................... 253 A/D Conversion (Sleep Mode) .................................. 254 Asynchronous Reception .......................................... 156 Asynchronous Transmission ..................................... 152 Asynchronous Transmission (Back to Back) ............ 152 Auto Wake-up Bit (WUE) During Normal Operation . 166 Auto Wake-up Bit (WUE) During Sleep .................... 167 Automatic Baud Rate Calculator ............................... 165 Brown-out Reset (BOR) ............................................ 241 Brown-out Reset Situations ...................................... 198 CLKOUT and I/O....................................................... 240 Clock Synchronization .............................................. 192 Clock Timing ............................................................. 238 Comparator Output ..................................................... 93 Enhanced Capture/Compare/PWM (ECCP) ............. 244 EUSART Synchronous Receive (Master/Slave) ....... 246 EUSART Synchronous Transmission (Master/Slave)................................................... 246 Fail-Safe Clock Monitor (FSCM) ................................. 58 Full-Bridge PWM Output ........................................... 138 Half-Bridge PWM Output .................................. 136, 143 I2C Bus Data ............................................................. 250 I2C Bus Start/Stop Bits.............................................. 249 I2C Reception (7-bit Address) ................................... 186 I2C Slave Mode (Transmission, 10-bit Address) ....... 190 I2C Slave Mode with SEN = 0 (Reception, 10-bit Address).................................................. 188 I2C Transmission (7-bit Address) .............................. 189 INT Pin Interrupt........................................................ 206 Internal Oscillator Switch Timing................................. 54 PWM Auto-shutdown Auto-restart Enabled ......................................... 142 Firmware Restart .............................................. 142 PWM Direction Change ............................................ 139 PWM Direction Change at Near 100% Duty Cycle ... 140 PWM Output (Active-High)........................................ 134 PWM Output (Active-Low) ........................................ 135 Reset, WDT, OST and Power-up Timer ................... 241 Send Break Character Sequence ............................. 168 Slave Synchronization .............................................. 181 SPI Master Mode (CKE = 1, SMP = 1) ..................... 247 SPI Mode (Master Mode) .......................................... 180 SPI Mode (Slave Mode with CKE = 0) ...................... 182 SPI Mode (Slave Mode with CKE = 1) ...................... 182 SPI Slave Mode (CKE = 0) ....................................... 248 SPI Slave Mode (CKE = 1) ....................................... 248 Synchronous Reception (Master Mode, SREN) ....... 172 Synchronous Transmission....................................... 170 Synchronous Transmission (Through TXEN) ........... 170 Time-out Sequence Case 1............................................................... 200 Case 2............................................................... 200 Case 3............................................................... 200 Timer0 and Timer1 External Clock ........................... 243 Timer1 Incrementing Edge.......................................... 87 Two Speed Start-up .................................................... 56 Wake-up from Interrupt ............................................. 211 Timing Parameter Symbology .......................................... 237 Timing Requirements I2C Bus Data............................................................. 251 I2C Bus Start/Stop Bits ............................................. 250 SPI Mode .................................................................. 249 TRISA Registers .................................................................... 59 TRISA Register................................................................... 59 TRISB Registers .................................................................... 69 TRISB Register................................................................... 70 TRISC Registers .................................................................... 76 TRISC Register................................................................... 76 Two-Speed Clock Start-up Mode........................................ 55 TXREG ............................................................................. 151 TXSTA Register................................................................ 158 BRGH Bit .................................................................. 161
U
UA..................................................................................... 176 Ultra Low-Power Wake-up.............. 14, 16, 18, 20, 22, 60, 63 Update Address bit, UA .................................................... 176
V
Voltage Reference (VR) Specifications ........................................................... 245 Voltage Reference. See Comparator Voltage Reference (CVREF) Voltage References Associated registers ................................................. 106 VP6 Stabilization ...................................................... 105 VRCON Register .............................................................. 106 VREF. SEE ADC Reference Voltage
W
Wake-up on Break ............................................................ 166 Wake-up Using Interrupts ................................................. 210 Watchdog Timer (WDT).................................................... 208 Associated registers ................................................. 209 Clock Source ............................................................ 208 Modes ....................................................................... 208 Period ....................................................................... 208 Specifications ........................................................... 242 WCOL bit .......................................................................... 177 WDTCON Register ........................................................... 209 WPUA Register................................................................... 62 WPUB Register................................................................... 70 Write Collision Detect bit (WCOL) .................................... 177 WWW Address ................................................................. 289 WWW, On-Line Support ....................................................... 8
DS41262D-page 288
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
THE MICROCHIP WEB SITE
Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site contains the following information: * Product Support - Data sheets and errata, application notes and sample programs, design resources, user's guides and hardware support documents, latest software releases and archived software * General Technical Support - Frequently Asked Questions (FAQ), technical support requests, online discussion groups, Microchip consultant program member listing * Business of Microchip - Product selector and ordering guides, latest Microchip press releases, listing of seminars and events, listings of Microchip sales offices, distributors and factory representatives
CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels: * * * * * Distributor or Representative Local Sales Office Field Application Engineer (FAE) Technical Support Development Systems Information Line
Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document. Technical support is available through the web site at: http://support.microchip.com
CUSTOMER CHANGE NOTIFICATION SERVICE
Microchip's customer notification service helps keep customers current on Microchip products. Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest. To register, access the Microchip web site at www.microchip.com, click on Customer Change Notification and follow the registration instructions.
(c) 2007 Microchip Technology Inc.
DS41262D-page 289
PIC16F631/677/685/687/689/690
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? Y N Literature Number: DS41262D FAX: (______) _________ - _________
Device: PIC16F631/677/685/687/689/690 Questions:
1. What are the best features of this document?
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?
DS41262D-page 290
(c) 2007 Microchip Technology Inc.
PIC16F631/677/685/687/689/690
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) b) Device: PIC16F631(1), PIC16F677(1), PIC16F685(1), PIC16F687(1), PIC16F689(1), PIC16F690(1); VDD range 2.0V to 5.5V c) PIC16F685 - I/ML 301 = Industrial temp., QFN package, QTP pattern #301. PIC16F689 - I/SO = Industrial temp., SOIC package. PIC16F690T - T/E/SS = Extended temp., SSOP package.
Temperature Range:
I E
= -40C to +85C = -40C to +125C
(Industrial) (Extended)
Package:
ML P SO SS
= = = =
QFN (Quad Flat, no lead) PDIP SOIC SSOP Note 1: T = in tape and reel SSOP, SOIC and QFN packages only.
Pattern:
QTP, SQTP, Code or Special Requirements (blank otherwise)
(c) 2007 Microchip Technology Inc.
DS41262D-page 291
WORLDWIDE SALES AND SERVICE
AMERICAS
Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: http://support.microchip.com Web Address: www.microchip.com Atlanta Duluth, GA Tel: 678-957-9614 Fax: 678-957-1455 Boston Westborough, MA Tel: 774-760-0087 Fax: 774-760-0088 Chicago Itasca, IL Tel: 630-285-0071 Fax: 630-285-0075 Dallas Addison, TX Tel: 972-818-7423 Fax: 972-818-2924 Detroit Farmington Hills, MI Tel: 248-538-2250 Fax: 248-538-2260 Kokomo Kokomo, IN Tel: 765-864-8360 Fax: 765-864-8387 Los Angeles Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 Santa Clara Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445 Toronto Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509
ASIA/PACIFIC
Asia Pacific Office Suites 3707-14, 37th Floor Tower 6, The Gateway Habour City, Kowloon Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 Australia - Sydney Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 China - Beijing Tel: 86-10-8528-2100 Fax: 86-10-8528-2104 China - Chengdu Tel: 86-28-8665-5511 Fax: 86-28-8665-7889 China - Fuzhou Tel: 86-591-8750-3506 Fax: 86-591-8750-3521 China - Hong Kong SAR Tel: 852-2401-1200 Fax: 852-2401-3431 China - Qingdao Tel: 86-532-8502-7355 Fax: 86-532-8502-7205 China - Shanghai Tel: 86-21-5407-5533 Fax: 86-21-5407-5066 China - Shenyang Tel: 86-24-2334-2829 Fax: 86-24-2334-2393 China - Shenzhen Tel: 86-755-8203-2660 Fax: 86-755-8203-1760 China - Shunde Tel: 86-757-2839-5507 Fax: 86-757-2839-5571 China - Wuhan Tel: 86-27-5980-5300 Fax: 86-27-5980-5118 China - Xian Tel: 86-29-8833-7250 Fax: 86-29-8833-7256
ASIA/PACIFIC
India - Bangalore Tel: 91-80-4182-8400 Fax: 91-80-4182-8422 India - New Delhi Tel: 91-11-4160-8631 Fax: 91-11-4160-8632 India - Pune Tel: 91-20-2566-1512 Fax: 91-20-2566-1513 Japan - Yokohama Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Korea - Gumi Tel: 82-54-473-4301 Fax: 82-54-473-4302 Korea - Seoul Tel: 82-2-554-7200 Fax: 82-2-558-5932 or 82-2-558-5934 Malaysia - Penang Tel: 60-4-646-8870 Fax: 60-4-646-5086 Philippines - Manila Tel: 63-2-634-9065 Fax: 63-2-634-9069 Singapore Tel: 65-6334-8870 Fax: 65-6334-8850 Taiwan - Hsin Chu Tel: 886-3-572-9526 Fax: 886-3-572-6459 Taiwan - Kaohsiung Tel: 886-7-536-4818 Fax: 886-7-536-4803 Taiwan - Taipei Tel: 886-2-2500-6610 Fax: 886-2-2508-0102 Thailand - Bangkok Tel: 66-2-694-1351 Fax: 66-2-694-1350
EUROPE
Austria - Wels Tel: 43-7242-2244-39 Fax: 43-7242-2244-393 Denmark - Copenhagen Tel: 45-4450-2828 Fax: 45-4485-2829 France - Paris Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 Germany - Munich Tel: 49-89-627-144-0 Fax: 49-89-627-144-44 Italy - Milan Tel: 39-0331-742611 Fax: 39-0331-466781 Netherlands - Drunen Tel: 31-416-690399 Fax: 31-416-690340 Spain - Madrid Tel: 34-91-708-08-90 Fax: 34-91-708-08-91 UK - Wokingham Tel: 44-118-921-5869 Fax: 44-118-921-5820
12/08/06
DS41262D-page 292
(c) 2007 Microchip Technology Inc.

▲Up To Search▲

Price & Availability of PIC16F685-IMLQTP

	To Download PIC16F685-IMLQTP Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .