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CP3CN23 Connectivity Processor with Bluetooth and Dual CAN Interfaces
PRELIMINARY
MAY 2004
CP3CN23 Reprogrammable Connectivity Processor with Dual CAN Interfaces
1.0 General Description
trade-off between battery size and operating time for handheld and portable applications. In addition to providing the features needed for the next generation of embedded products, the CP3CN23 is backed up by the software resources designers need for rapid time-tomarket, including an operating system, peripheral drivers, reference designs, and an integrated development environment. National Semiconductor offers a complete and industryproven application development environment for CP3CN23 applications, including the IAR Embedded Workbench, iSYSTEM winIDEA and iC3000 Active Emulator, and Application Software. The CP3CN23 connectivity processor combines high performance with the massive integration needed for embedded applications. A powerful RISC core with on-chip SRAM and Flash memory provides high computing bandwidth, hardware communications peripherals provide high-I/O bandwidth, and an external bus provides system expandability. On-chip communications peripherals include: dual CAN controllers, Microwire/Plus, SPI, ACCESS.bus, quad UART, 12-bit A/D converter, and Advanced Audio Interface (AAI). Additional on-chip peripherals include Random Number Generator (RNG), DMA controller, CVSD/PCM conversion module, Timing and Watchdog Unit, Versatile Timer Unit, Multi-Function Timer, and Multi-Input Wake-Up (MIWU) unit. Hand-held devices can be both smaller and lower in cost for maximum consumer appeal. The low voltage and advanced power-saving modes achieve new design points in the
Block Diagram
Clock Generator
12 MHz and 32 kHz Oscillator
PLL and Clock Generator
Power-on-Reset
CR16C CPU Core
256K Bytes Flash Program Memory
8K Bytes Flash Data
32K Bytes Static RAM
Dual CAN 2.0B Controller
Serial Debug Interface
CPU Core Bus
Bus Interface Unit
DMA Controller
Peripheral Bus Controller
Interrupt Control Unit
CVSD/PCM Converter
Power Management
Timing and Watchdog Unit
Random Number Generator
Peripheral Bus
GPIO
Audio Interface
Microwiire/ SPI
Quad UART
ACCESS .bus
Versatile Timer Unit
Muti-Function Timer
Multi-Input Wake-Up
8-Channel 12-bit ADC
DS310
TRI-STATE is a registered trademark of National Semiconductor Corporation.
(c)2004 National Semiconductor Corporation
www.national.com
CP3CN23
Table of Contents
1.0 2.0 3.0 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Device Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 CR16C CPU Core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Input/Output Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bus Interface Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Control Unit (ICU). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multi-Input Wake-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CAN Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quad UART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Advanced Audio interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CVSD/PCM Conversion Module. . . . . . . . . . . . . . . . . . . . . . . . . . . 12-bit Analog to Digital Converter. . . . . . . . . . . . . . . . . . . . . . . . . . Random Number Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microwire/SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ACCESS.bus Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multi-Function Timer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timing and Watchdog Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . Versatile Timer Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Triple Clock and Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DMA Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Serial Debug Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Development Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4 4 4 4 4 5 5 5 5 5 5 6 6 6 6 6 6 6 7 7 7
17.0
CAN Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 17.10 17.11 17.12 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Basic CAN Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Message Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Acceptance Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Receive Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Transmit Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Time Stamp Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 CAN Controller Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 System Start-Up and Multi-Input Wake-Up. . . . . . . . . . . . . . . . . 113 Usage Hint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Audio Interface Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Audio Interface Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bit Clock Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frame Clock Generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Audio Interface Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Communication Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Audio Interface Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PCM Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CVSD Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PCM to CVSD Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CVSD to PCM Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DMA Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Freeze. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CVSD/PCM Converter Registers . . . . . . . . . . . . . . . . . . . . . . . . Functional Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . UART Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . UART Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baud Rate Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microwire Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Master Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microwire Interface Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . ACB Protocol Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ACB Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . ACCESS.bus Interface Registers . . . . . . . . . . . . . . . . . . . . . . . . Usage Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TWM Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer T0 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TWM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Programming Procedure . . . . . . . . . . . . . . . . . . . . . . Timer Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer I/O Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 116 119 119 119 121 124 131 131 132 132 132 132 132 133 133 136 136 141 145 148 150 151 151 152 154 156 158 162 165 165 166 166 168 169 170 175 175 176
18.0
Advanced Audio Interface . . . . . . . . . . . . . . . . . . . . 116
18.1 18.2 18.3 18.4 18.5 18.6 18.7
19.0
CVSD/PCM Conversion Module . . . . . . . . . . . . . . . 131
19.1 19.2 19.3 19.4 19.5 19.6 19.7 19.8 19.9
4.0 5.0
Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 CPU Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1 5.2 5.3 5.4 5.5 5.6 5.7 General-Purpose Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dedicated Address Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . Processor Status Register (PSR) . . . . . . . . . . . . . . . . . . . . . . . . . Configuration Register (CFG). . . . . . . . . . . . . . . . . . . . . . . . . . . . Addressing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stacks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instruction Set. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operating Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bus Interface Unit (BIU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bus Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BIU Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait and Hold States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 15 16 17 18 19 19 24 25 25 25 28
20.0
UART Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
20.1 20.2 20.3 20.4
6.0
Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.1 6.2 6.3 6.4 6.5
21.0
Microwire/SPI Interface . . . . . . . . . . . . . . . . . . . . . . 148
21.1 21.2 21.3 21.4 21.5
7.0
System Configuration Registers . . . . . . . . . . . . . . . 29
7.1 7.2 7.3 Module Configuration Register (MCFG) . . . . . . . . . . . . . . . . . . . . 29 Module Status Register (MSTAT). . . . . . . . . . . . . . . . . . . . . . . . . 30 Software Reset Register (SWRESET) . . . . . . . . . . . . . . . . . . . . . 30 Flash Memory Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Memory Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Information Block Words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Memory Interface Registers . . . . . . . . . . . . . . . . . . . . . . . . Channel Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transfer Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Software DMA Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DMA Controller Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . Non-Maskable Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maskable Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Controller Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maskable Interrupt Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nested Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Crystal Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Main Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Slow Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PLL Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . System Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Auxiliary Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clock and Reset Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Active Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Save Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Idle Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Halt Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . High-Frequency Oscillator and PLL Control . . . . . . . . . . . . . . . . . Power Management Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . Switching Between Power Modes . . . . . . . . . . . . . . . . . . . . . . . . 31 31 32 34 35 41 41 42 43 43 43 47 47 47 50 50 52 53 53 53 54 54 54 54 54 56 56 57 57 57 57 59
22.0
ACCESS.bus Interface . . . . . . . . . . . . . . . . . . . . . . . 154
22.1 22.2 22.3 22.4
8.0
Flash Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.1 8.2 8.3 8.4 8.5
23.0
Timing and Watchdog Module . . . . . . . . . . . . . . . . 165
23.1 23.2 23.3 23.4 23.5
9.0
DMA Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.1 9.2 9.3 9.4 9.5 9.6
24.0
Multi-Function Timer . . . . . . . . . . . . . . . . . . . . . . . . 169
24.1 24.2 24.3 24.4 24.5
10.0
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.1 10.2 10.3 10.4 10.5
25.0 26.0 27.0 28.0
Versatile Timer Unit (VTU) . . . . . . . . . . . . . . . . . . . . 179
25.1 25.2 VTU Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 VTU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
11.0
Triple Clock and Reset . . . . . . . . . . . . . . . . . . . . . . . 51
11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9
Register Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Register Bit Fields . . . . . . . . . . . . . . . . . . . . . . . . . . 202 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . 212
28.1 28.2 28.3 28.4 28.5 28.6 28.7 28.8 28.9 28.10 28.11 28.12 28.13 28.14 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Memory On-Chip Programming . . . . . . . . . . . . . . . . . . . . Output Signal Levels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clock and Reset Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . UART Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I/O Port Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Advanced Audio Interface (AAI) Timing . . . . . . . . . . . . . . . . . . . Microwire/SPI Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ACCESS.bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multi-Function Timer (MFT) Timing . . . . . . . . . . . . . . . . . . . . . . Versatile Timing Unit (VTU) Timing . . . . . . . . . . . . . . . . . . . . . . External Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 212 213 214 215 215 217 218 219 221 226 229 230 231
12.0
Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . 56
12.1 12.2 12.3 12.4 12.5 12.6 12.7
29.0 30.0 31.0
Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
29.1 29.2 LQFP-128 Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 LQFP-144 Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
13.0 14.0 15.0
Multi-Input Wake-Up . . . . . . . . . . . . . . . . . . . . . . . . . 61
13.1 13.2 14.1 14.2 15.1 15.2 15.3 15.4 15.5 Multi-Input Wake-Up Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Programming Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Port Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Open-Drain Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Touchscreen Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Operation in Power-Saving Modes . . . . . . . . . . . . . . . . . . . Freeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 73 75 75 75
Input/Output Ports. . . . . . . . . . . . . . . . . . . . . . . . . . . 67 12-Bit Analog to Digital Converter . . . . . . . . . . . . . . 71
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . 245
16.0
Random Number Generator (RNG) . . . . . . . . . . . . . 80
16.1 16.2 Freeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Random Number Generator Register Set . . . . . . . . . . . . . . . . . . 81
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2
CP3CN23
2.0
Features
Extensive Power and Clock Management Support On-chip Phase Locked Loop Support for multiple clock options Dual clock and reset Power-down modes
CPU Features
Fully static RISC processor core, capable of operating from 0 to 24 MHz with zero wait/hold states Minimum 41.7 ns instruction cycle time with a 24-MHz internal clock frequency, based on a 12-MHz external input Flexible I/O 47 independently vectored peripheral interrupts Up to 56 general-purpose I/O pins (shared with on-chip peripheral I/O) On-Chip Memory Programmable I/O pin characteristics: TRI-STATE out256K bytes reprogrammable Flash program memory put, push-pull output, weak pull-up input, high-imped8K bytes Flash data memory ance input 32K bytes of static RAM data memory Schmitt triggers on general-purpose inputs Addresses up to 12M bytes of external memory Multi-Input Wake-Up (MIWU) capability Broad Range of Hardware Communications Peripherals Power Supply ACCESS.bus serial bus (compatible with Philips I2C bus) I/O port operation at 2.5V to 3.3V Dual CAN interface with 15 message buffers conforming Core logic operation at 2.5V to CAN specification 2.0B active On-chip power-on reset 8/16-bit SPI, Microwire/Plus serial interface Four-channel Universal Asynchronous Receiver/Trans- Temperature Range mitter (UART), one channel has USART capability -40C to +85C (Industrial) Advanced Audio Interface (AAI) to connect to external 8/ Packages 13-bit PCM Codecs as well as to ISDN-Controllers LQFP-128, LQFP-144 through the IOM-2 interface (slave only) CVSD/PCM converter supporting one bidirectional audio Complete Development Environment connection Pre-integrated hardware and software support for rapid General-Purpose Hardware Peripherals prototyping and production Integrated environment 12-bit A/D Converter (ADC) Project manager Dual 16-bit Multi-Function Timer (MFT) Multi-file C source editor Versatile Timer Unit with four subsystems (VTU) High-level C source debugger Four-channel DMA controller Comprehensive, integrated, one-stop technical support Timing and Watchdog Unit Random Number Generator peripheral
CP3CN23 Connectivity Processor Selection Guide NSID CP3CN23G18NEP CP3CN23G18NEPNOPB CP3CN23G18NEPX CP3CN23G18NEPXNOPB CP3CN23Y98NEP CP3CN23Y98NEPNOPB CP3CN23Y98NEPX CP3CN23Y98NEPXNOPB Speed Temp. Range (MHz) 24 24 24 24 24 24 24 24 -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C Program Flash (Kbytes) 256 256 256 256 256 256 256 256 Data Flash (Kbytes) 8 8 8 8 8 8 8 8 SRAM (Kbytes) 32 32 32 32 32 32 32 32 External Address Lines 0 0 0 0 23 23 23 23 I/Os 56 56 56 56 50 50 50 50 Package Type LQFP-128 LQFP-128 LQFP-128 LQFP-128 LQFP-144 LQFP-144 LQFP-144 LQFP-144
NEP - Erased part (serial number in Information Block 1); X - Tape and reel; NOPB - No lead solder
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CP3CN23
3.0
Device Overview
3.3 INPUT/OUTPUT PORTS
The device has up to 50 software-configurable I/O pins, organized into seven ports called Port B, Port C, Port E, Port G, Port H, Port I, and Port J. Each pin can be configured to operate as a general-purpose input or general-purpose output. In addition, many I/O pins can be configured to operate as inputs or outputs for on-chip peripheral modules such as the UART, timers, or Microwire/SPI interface. The I/O pin characteristics are fully programmable. Each pin can be configured to operate as a TRI-STATE output, pushpull output, weak pull-up input, or high-impedance input.
The CP3CN23 connectivity processor is a complete microcomputer with all system timing, interrupt logic, program memory, data memory, and I/O ports included on-chip, making it well-suited to a wide range of embedded applications. The block diagram on page 1 shows the major on-chip components of the CP3CN23 devices.
3.1
CR16C CPU CORE
The CP3CN23 device implements the CR16C CPU core module. The high performance of the CPU core results from the implementation of a pipelined architecture with a twobytes-per-cycle pipelined system bus. As a result, the CPU can support a peak execution rate of one instruction per clock cycle. For more information, please refer to the CR16C Programmer's Reference Manual (document number 424521772101, which may be downloaded from National's web site at http://www.national.com).
3.4
BUS INTERFACE UNIT
The Bus Interface Unit (BIU) controls access to internal/external memory and I/O. It determines the configured parameters for bus access (such as the number of wait states for memory access) and issues the appropriate bus signals for each requested access. The BIU uses a set of control registers to determine how many wait states and hold states are used when accessing Flash program memory and the I/O area. At start-up, the configuration registers are set for slowest possible memory access. To achieve fastest possible program execution, appropriate values must be programmed. These settings vary with the clock frequency and the type of off-chip device being accessed.
3.2
MEMORY
The CP3CN23 devices support a uniform linear address space of up to 16 megabytes. Three types of on-chip memory occupy specific regions within this address space, along with any external memory: 256K bytes of Flash program memory 8K bytes of Flash data memory 32K bytes of static RAM Up to 12M bytes of external memory (144-pin devices) The 256K bytes of Flash program memory are used to store the application program and real-time operating system. The Flash memory has security features to prevent unintentional programming and to prevent unauthorized access to the program code. This memory can be programmed with an external programming unit or with the device installed in the application system (in-system programming).
3.5
INTERRUPT CONTROL UNIT (ICU)
The ICU receives interrupt requests from internal and external sources and generates interrupts to the CPU. An interrupt is an event that temporarily stops the normal flow of program execution and causes a separate interrupt handler to be executed. After the interrupt is serviced, CPU execution continues with the next instruction in the program following the point of interruption.
The 8K bytes of Flash data memory are used for non-vola- Interrupts from the timers, UARTs, Microwire/SPI interface, tile storage of data entered by the end-user, such as config- and Multi-Input Wake-Up, are all maskable interrupts; they uration settings. can be enabled or disabled by software. There are 47 The 32K bytes of static RAM are used for temporary storage maskable interrupts, assigned to 47 linear priority levels. of data and for the program stack and interrupt stack. Read and write operations can be byte-wide or word-wide, depending on the instruction executed by the CPU. The highest-priority interrupt is the Non-Maskable Interrupt (NMI), which is generated by a signal received on the NMI input pin.
Up to 12M bytes of external memory can be added on an 3.6 MULTI-INPUT WAKE-UP external bus. The external bus is only available on devices The two Multi-Input Wake-Up (MIWU) modules can be used in 144-pin packages. for two purposes: to provide inputs for waking up (exiting) For Flash program and data memory, the device internally from the Halt, Idle, or Power Save mode, and to provide gengenerates the necessary voltages for programming. No ad- eral-purpose edge-triggered maskable interrupts to the levditional power supply is required. el-sensitive interrupt control unit (ICU) inputs. Each 16channel module generates four programmable interrupts to the ICU, for a total of 8 ICU inputs generated from 32 MIWU inputs. Channels can be individually enabled or disabled, and programmed to respond to positive or negative edges.
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CP3CN23
3.7
CAN INTERFACE
3.11
Two CAN modules provide Full CAN 2.0B class, CAN serial bus interface for applications that require a high-speed (up to 1 Mbits per second) or a low-speed interface with CAN bus master capability. The data transfer between CAN and the CPU is established by 15 memory-mapped message buffers, which can be individually configured as receive or transmit buffers. An incoming message is filtered by two masks, one for the first 14 message buffers and another one for the 15th message buffer to provide a basic CAN path. A priority decoder allows any buffer to have the highest or lowest transmit priority. Remote transmission requests can be processed automatically by automatic reconfiguration to a receiver after transmission or by automated transmit scheduling upon reception. In addition, a time stamp counter (16bits wide) is provided to support real-time applications. The CAN modules are fast core bus peripherals, which allow single-cycle byte or word read/write access. A set of diagnostic features (such as loopback, listen only, and error identification) support the development with the CAN module and provide a sophisticated error management tool. The CAN receivers can trigger a wake-up condition out of the low-power modes through the Multi-Input Wake-Up module.
12-BIT ANALOG TO DIGITAL CONVERTER
This device contains an 8-channel, multiplexed input, successive approximation, 12-bit Analog-to-Digital Converter. It supports both Single Ended and Differential modes of operation. The integrated 12-bit ADC provides the following features: 8-channel, multiplexed input 4 differential channels Single-ended and differential external filtering capability 12-bit resolution; 11-bit accuracy 15-microsecond conversion time Support for 4-wire touchscreen applications External start trigger Programmable start delay after start trigger Poll or interrupt on done The ADC is compatible with 4-wire resistive touchscreen applications and is intended to provide the resolution necessary to support handwriting recognition. Low-ohmic touchscreen drivers are provided internally on the ADC[3:0] pins. Pendown detection is also provided. The ADC provides several options for the voltage reference source. The positive reference can be ADVCC (internal), VREFP, ADC0, or ADC3. The negative reference can be ADVCC (internal), ADC1, or ADC2.
3.8
QUAD UART
Four UART modules support a wide range of programmable Two specific analog channel selection modes are supportbaud rates and data formats, parity generation, and several ed. These are as follows: error detection schemes. The baud rate is generated onAllow any specific channel to be selected at one time. chip, under software control. One UART channel supports The A/D Converter performs the specific conversion rehardware flow control, DMA, and USART capability (synquested and stops. chronous mode). Allow any differential channel pair to be selected at one The UARTs offer a wake-up condition from the low-power time. The A/D Converter performs the specific differential modes using the Multi-Input Wake-Up module. conversion requested and stops.
3.9
ADVANCED AUDIO INTERFACE
The audio interface provides a serial synchronous, full-duplex interface to CODECs and similar serial devices. Transmit and receive paths operate asynchronously with respect to each other. Each path uses three signals for communication: shift clock, frame synchronization, and data.
In both Single-Ended and Differential modes, there is the capability to connect the analog multiplexer output and A/D converter input to external pins. This provides the ability to externally connect a common filter/signal conditioning circuit for the A/D Converter.
3.12
RANDOM NUMBER GENERATOR
When the receiver and transmitter use separate shift clocks RNG peripheral for use in Trusted Computer Peripheral Apand frame sync signals, the interface operates in its asyn- plications (TCPA) to improve the authenticity, integrity, and chronous mode. Alternatively, the transmit and receive path privacy of Internet-based communication and commerce. can share the same shift clock and frame sync signals for synchronous mode operation.
3.10
CVSD/PCM CONVERSION MODULE
The CVSD/PCM module performs conversion between CVSD data and PCM data, in which the CVSD encoding is as defined in the Bluetooth specification and the PCM data can be 8-bit -Law, 8-bit A-Law, or 13-bit to 16-bit Linear.
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CP3CN23
3.13
MICROWIRE/SPI
3.17
VERSATILE TIMER UNIT
The Microwire/SPI (MWSPI) interface module supports synchronous serial communications with other devices that conform to Microwire or Serial Peripheral Interface (SPI) specifications. It supports 8-bit and 16-bit data transfers.
The Versatile Timer Unit (VTU) module contains four independent timer subsystems, each operating in either dual 8bit PWM configuration, as a single 16-bit PWM timer, or a 16-bit counter with two input capture channels. Each of the The Microwire interface allows several devices to communi- four timer subsystems offer an 8-bit clock prescaler to accate over a single system consisting of four wires: serial in, commodate a wide range of frequencies. serial out, shift clock, and slave enable. At any given time, 3.18 TRIPLE CLOCK AND RESET the Microwire interface operates as the master or a slave. The Microwire interface supports the full set of slave select The Triple Clock and Reset module generates a high-speed main System Clock from an external crystal network. It also for multi-slave implementation. provides the main system reset signal and a power-on reset In master mode, the shift clock is generated on-chip under function. software control. In slave mode, a wake-up out of a lowpower mode may be triggered using the Multi-Input Wake- This module generates a slow System Clock (32.768 kHz) from an optional external crystal network. The Slow Clock is Up module. used for operating the device in a low-power mode. The 3.14 ACCESS.BUS INTERFACE 32.768 kHz external crystal network is optional, because The ACCESS.bus interface module (ACB) is a two-wire se- the low speed System Clock can be derived from the highrial interface compatible with the ACCESS.bus physical lay- speed clock by a prescaler. Also, two independent clocks dier. It is also compatible with Intel's System Management vided down from the high speed clock are available on outBus (SMBus) and Philips' I2C bus. The ACB module can be put pins. configured as a bus master or slave, and it can maintain bi- The Triple Clock and Reset module provides the clock sigdirectional communications with both multiple master and nals required for the operation of the various CP3CN23 onslave devices. chip modules. From external crystal networks, it generates The ACCESS.bus receiver can trigger a wake-up condition the Main Clock, which can be scaled up to 24 MHz from an out of the low-power modes through the Multi-Input Wake- external 12 MHz input clock, and a 32.768 kHz secondary System Clock. The 12 MHz external clock is primarily used Up module. as the reference frequency for the on-chip PLL. The clock 3.15 MULTI-FUNCTION TIMER for modules which require a fixed clock rate (e.g. the CVSD/ The Multi-Function Timer (MFT) module contains a pair of PCM transcoder) is also generated through prescalers from 16-bit timer/counter registers. Each timer/counter unit can the 12 MHz clock. The PLL may be used to drive the highspeed System Clock through a prescaler. Alternatively, the be configured to operate in any of the following modes: high speed System Clock can be derived directly from the -- Processor-Independent Pulse Width Modulation 12 MHz Main Clock. (PWM) mode: Generates pulses of a specified width and duty cycle and provides a general-purpose timer/ In addition, this module generates the device reset by using reset input signals coming from an external reset and varicounter. -- Dual Input Capture mode: Measures the elapsed time ous on-chip modules. between occurrences of external event and provides 3.19 POWER MANAGEMENT a general-purpose timer/counter. -- Dual Independent Timer mode: Generates system The Power Management Module (PMM) improves the effitiming signals or counts occurrences of external ciency of the device by changing the operating mode and power consumption to match the required level of activity. events. -- Single Input Capture and Single Timer mode: Provides one external event counter and one system timer. The device can operate in any of four power modes: -- Active: The device operates at full speed using the high-frequency clock. All device functions are fully operational. -- Power Save: The device operates at reduced speed using the Slow Clock. The CPU and some modules can continue to operate at this low speed. -- Idle: The device is inactive except for the Power Management Module and Timing and Watchdog Module, which continue to operate using the Slow Clock. -- Halt: The device is inactive but still retains its internal state (RAM and register contents).
3.16
TIMING AND WATCHDOG MODULE
The Timing and Watchdog Module (TWM) contains a RealTime timer and a Watchdog unit. The Real-Time Clock Timing function can be used to generate periodic real-time based system interrupts. The timer output is one of 16 inputs to the Multi-Input Wake-Up module which can be used to exit from a power-saving mode. The Watchdog unit is designed to detect the application program getting stuck in an infinite loop resulting in loss of program control or "runaway" programs. When the watchdog triggers, it resets the device. The TWM is clocked by the low-speed System Clock.
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CP3CN23
3.20
DMA CONTROLLER
3.21
SERIAL DEBUG INTERFACE
The Direct Memory Access Controller (DMAC) can speed up data transfer between memory and I/O devices or between two memories, relative to data transfers performed directly by the CPU. A method called cycle-stealing allows the CPU and the DMAC to share the CPU bus efficiently. The DMAC implements four independent DMA channels. DMA requests from a primary and a secondary source are recognized for each DMA channel, as well as a software DMA request issued directly by the CPU. Table 1 shows the DMA channel assignment on the CP3CN23 architecture. The following on-chip modules can assert a DMA request to the DMAC: * * * * CR16C (Software DMA request) USART Advanced Audio Interface CVSD/PCM Converter
The Serial Debug Interface module (SDI module) provides a JTAG-based serial link to an external debugger, for example running on a PC. In addition, the SDI module integrates an on-chip debug module, which allows the user to set up to eight hardware breakpoints on instruction execution and data transfer. The SDI module can act as a CPU bus master to access all memory mapped resources, such as RAM and peripherals. Therefore it also allows for fast program code download into the on-chip Flash program memory using the JTAG interface.
3.22
DEVELOPMENT SUPPORT
Table 1 shows how the four DMA channels are assigned to the modules listed above. Table 1 Channel DMA Channel Assignment Peripheral Reserved UART0 UART0 Unused AAI CVSD/PCM AAI CVSD/PCM Transaction Read/Write Read Write N/A Read Read Write Write
In addition to providing the features needed for the next generation of embedded products, the CP3CN23 devices are backed up by the software resources designers need for rapid product development, including an operating system, peripheral drivers, reference designs, and an integrated development environment. National Semiconductor offers a complete and industryproven application development environment for CP3CN23 applications, including the IAR Embedded Workbench, iSYSTEM winIDEA and iC3000 Active Emulator, and Application Software. See your National Semiconductor sales representative for current information on availability and features of emulation equipment and evaluation boards.
Primary/ Secondary Primary
0 Secondary Primary 1 Secondary Primary 2 Secondary Primary 3 Secondary
The interface can handle data words of either 8- or 16-bit length and data frames can consist of up to four slots. In the normal mode of operation, the interface only transfers one word at a periodic rate. In the network mode, the interface transfers multiple words at a periodic rate. The periodic rate is also called a data frame and each word within one frame is called a slot. The beginning of each new data frame is marked by the frame sync signal.
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CP3CN23
4.0
Signal Descriptions
X1CKI/BBCLK X1CKO X2CKI X2CKO
1 1 1
12 MHz Crystal or Ext. Clock 32.768 kHz Crystal
PB[7:0] PC[7:0]
8 8
12 MHz Crystal GPIO or Ext. Clock 32.768 kHz Crystal
1 1 1
X1CKI/BBCLK X1CKO X2CKI X2CKO AVCC AGND ADVCC ADGND VCC GND IOVCC IOGND RESET TMS TDI TDO TCK RDY ENV0 ENV1 ENV2 PG7/TA
Power Supply
1 6 6 15 14
AVCC AGND ADVCC ADGND VCC GND IOVCC IOGND RESET TMS TDI TDO TCK RDY ENV0 ENV1 ENV2 PG7/TA
CP3CN23 (LQFP-128)
PGO PG1 PG3 PG4 PG5 PE0/RXD0 PE1/TXD0 PE2/RTS PE3/CTS PE4/CKX/TB PH0/RXD1/WUI11 PH1/TXD1/WUI12 GPIO
Power Supply
1 6 6 10 11
CP3CN23 (LQFP-144)
PB[7:0] PC[7:0] A[22:0] SEL0 SEL1 SEL2 SELIO WR0 WR1 RD
8 8 23
External Bus Interface
PGO PG1 PG3 PG4 PG5 PE0/RXD0 PE1/TXD0 PE2/RTS PE3/CTS PE4/CKX/TB PH0/RXD1/WUI11 PH1/TXD1/WUI12 GPIO
Chip Reset
Chip Reset
JTAG I/F to Debugger/ Programmer
JTAG I/F to Debugger/ Programmer UART0
UART0
Mode Selection
UART0/MFT Mode Selection UART1/MIWU MFT UART2/MIWU
UART0/MFT UART1/MIWU
MFT
ADC/ Touchscreen
ACCESS.bus
PH2/RXD1/WUI13 ADC0/TSX+ PH3/TXD1/WUI14 ADC1/TSY+ PH4/RXD1/WUI15 ADC2/TSXPH5/TXD1/WUI16 ADC3/TSYADC4/MUXOUT0 ADC5/MUXOUT1 PF0/MSK/TIO1 ADC6 PF1/MDIDO/TIO2 ADC7/ADCIN PF2/MDODO/TIO3 PJ7/ASYNC/ PF3/MWCS/TIO4 WUI9 VREFP PF4/SCK/TIO5 PF5/SFS/TIO6 PF6/STD/TIO7 SDA PF7/SRD/TIO8 SCL PE5/SRFS/NMI PH6/CAN0RX/ WUI17 PH7/CAN0TX PE6/CAN1RX PE7/CAN1TX PG2/SRCLK PJ0/WUI18 PJ1/WUI19 PJ2/WUI20 PJ3/WUI21 PJ4/WUI22 PJ5/WUI23 PJ6/WUI24 PG6/WUI10
UART3/MIWU ADC/ Touchscreen Microwire/ SPI/ VTU
AAI/ VTU ACCESS.bus AAI/NMI AAI CAN0 bus
PH2/RXD1/WUI13 ADC0/TSX+ PH3/TXD1/WUI14 ADC1/TSY+ PH4/RXD1/WUI15 ADC2/TSXPH5/TXD1/WUI16 ADC3/TSYADC4/MUXOUT0 ADC5/MUXOUT1 PF0/MSK/TIO1 ADC6 PF1/MDIDO/TIO2 ADC7/ADCIN PF2/MDODO/TIO3 PJ7/ASYNC/ PF3/MWCS/TIO4 WUI9 VREFP PF4/SCK/TIO5 PF5/SFS/TIO6 PF6/STD/TIO7 SDA PF7/SRD/TIO8 SCL PE5/SRFS/NMI PH6/CAN0RX/ WUI17 PH7/CAN0TX PE6/CAN1RX PE7/CAN1TX PG2/SRCLK PJ0/WUI18 PG6/WUI10
UART2/MIWU
UART3/MIWU
Microwire/ SPI/ VTU
AAI/ VTU
AAI/NMI AAI
CAN0 bus
MIWU
CAN1 bus
CAN1 bus MIWU
DS307
Figure 1.
CP3CN23 Device SIgnals
Some pins may be enabled as general-purpose I/O-port pins or as alternate functions associated with specific peripherals or interfaces. These pins may be individually configured as port pins, even when the associated peripheral or interface is enabled. Table 2 describes the device signals for the LQFP-128 package. Table 3 describes the device signals for the LQFP-144 package.
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CP3CN23
Table 2 CP3CN23 LQFP-128 Signal Descriptions Name X1CKI X1CKO X2CKI X2CKO RESET ENV0 ENV1 ENV2 TMS TCK TDI TDO RDY VCC GND IOVCC IOGND AVCC AGND ADVCC ADGND SCL SDA ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 ADC6 ADC7 Pins 1 1 1 1 1 1 1 1 1 1 1 1 1 6 6 16 15 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I/O Input Output Input Output Input I/O I/O I/O Input Input Input Output Output Input Input Input Input Input Input Input Input I/O I/O I/O I/O I/O I/O I/O I/O Input Input Primary Function 12 MHz Oscillator Input 12 MHz Oscillator Output 32 kHz Oscillator Input 32 kHz Oscillator Output Chip general reset Special mode select input with internal pull-up during reset Special mode select input with internal pull-up during reset Special mode select input with internal pull-up during reset JTAG Test Mode Select (with internal weak pull-up) JTAG Test Clock Input (with internal weak pull-up) JTAG Test Data Input (with internal weak pull-up) JTAG Test Data Output NEXUS Ready Output 2.5V Core Logic Power Supply Core Ground 2.5-3.3V I/O Power Supply I/O Ground PLL Analog Power Supply PLL Analog Ground ADC Analog Power Supply ADC Analog Ground ACCESS.bus Clock ACCESS.bus Serial Data ADC Input Channel 0 ADC Input Channel 1 ADC Input Channel 2 ADC Input Channel 3 ADC Input Channel 4 ADC Input Channel 5 ADC Input Channel 6 ADC Input Channel 7 Alternate Name BBCLK None None None None PLLCLK CPUCLK SLOWCLK None None None None None None None None None None None None None None None TSX+ TSY+ TSXTSYMUXOUT0 MUXOUT1 None ADCIN Alternate Function BB reference clock for the RF Interface None None None None PLL Clock Output CPU Clock Output Slow Clock Output None None None None None None None None None None None None None None None Touchscreen X+ contact Touchscreen Y+ contact Touchscreen X- contact Touchscreen Y- contact Analog Multiplexer Output 0 Analog Multiplexer Output 1 None ADC Input (in MUX mode)
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CP3CN23
Name VREFP PB[7:0] PC[7:0] PE0 PE1 PE2 PE3 PE4
Pins 1 8 8 1 1 1 1 1
I/O Input I/O I/O I/O I/O I/O I/O I/O
Primary Function ADC Positive Voltage Reference Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O
Alternate Name None None None RXD0 TXD0 RTS CTS CKX TB SRFS None None None
Alternate Function
UART Channel 0 Receive Data Input UART Channel 0 Transmit Data Output UART Channel 0 Ready-To-Send Output UART Channel 0 Clear-To-Send Input UART Channel 0 Clock Input Multi Function Timer Port B AAI Receive Frame Sync Non-Maskable Interrupt Input UART Channel 0 Ready-To-Send Output UART Channel 0 Clear-To-Send Input SPI Shift Clock Versatile Timer Channel 1 SPI Master In Slave Out Versatile Timer Channel 2 SPI Master Out Slave In Versatile Timer Channel 3 SPI Slave Select Input Versatile Timer Channel 4 AAI Clock Versatile Timer Channel 5 AAI Frame Synchronization Versatile Timer Channel 6 AAI Transmit Data Output Versatile Timer Channel 7 AAI Receive Data Input Versatile Timer Channel 8 None None AAI Receive Clock None None None Multi-Input Wake-Up Channel 10 Multi Function Timer Port A
PE5 PE6 PE7 PF0
1 1 1 1
I/O I/O I/O I/O
Generic I/O NMI Generic I/O Generic I/O Generic I/O TIO1 MDIDO CAN1RX CAN1TX MSK
PF1
1
I/O
Generic I/O TIO2 MDODI
PF2
1
I/O
Generic I/O TIO3 MWCS
PF3
1
I/O
Generic I/O TIO4 SCK
PF4
1
I/O
Generic I/O TIO5 SFS
PF5
1
I/O
Generic I/O TIO6 STD
PF6
1
I/O
Generic I/O TIO7 SRD
PF7 PG0 PG1 PG2 PG3 PG4 PG5 PG6 PG7
1 1 1 1 1 1 1 1 1
I/O I/O I/O I/O I/O I/O I/O I/O I/O
Generic I/O TIO8 Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O 10 None None SRCLK None None None WUI10 TA
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CP3CN23
Name
Pins
I/O
Primary Function
Alternate Name RXD1
Alternate Function UART Channel 1 Receive Data Input Multi-Input Wake-Up Channel 11 UART Channel 1 Transmit Data Output Multi-Input Wake-Up Channel 12 UART Channel 2 Receive Data Input Multi-Input Wake-Up Channel 13 UART Channel 2 Transmit Data Output Multi-Input Wake-Up Channel 14 UART Channel 3 Receive Data Input Multi-Input Wake-Up Channel 15 UART Channel 3 Transmit Data Output Multi-Input Wake-Up Channel 16 CAN Receive Input Multi-Input Wake-Up Channel 17 CAN Transmit Output Multi-Input Wake-Up Channel 18 Multi-Input Wake-Up Channel 19 Multi-Input Wake-Up Channel 20 Multi-Input Wake-Up Channel 21 Multi-Input Wake-Up Channel 22 Multi-Input Wake-Up Channel 23 Multi-Input Wake-Up Channel 24 Start convert signal to ADC Multi-Input Wake-Up Channel 9
PH0
1
I/O
Generic I/O WUI11 TXD1
PH1
1
I/O
Generic I/O WUI12 RXD2
PH2
1
I/O
Generic I/O WUI13 TXD2
PH3
1
I/O
Generic I/O WUI14 RXD3
PH4
1
I/O
Generic I/O WUI15 TXD3
PH5
1
I/O
Generic I/O WUI16 CAN0RX
PH6 PH7 PJ0 PJ1 PJ2 PJ3 PJ4 PJ5 PJ6 PJ7
1 1 1 1 1 1 1 1 1 1
I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O
Generic I/O WUI17 Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O WUI9 CAN0TX WUI18 WUI19 WUI20 WUI21 WUI22 WUI23 WUI24 ASYNC
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CP3CN23
Table 3 CP3CN23 LQFP-144 Signal Descriptions Name X1CKI X1CKO X2CKI X2CKO RESET ENV0 ENV1 ENV2 TMS TCK TDI TDO RDY VCC GND IOVCC IOGND AVCC AGND ADVCC ADGND SCL SDA ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 ADC6 ADC7 Pins 1 1 1 1 1 1 1 1 1 1 1 1 1 6 6 10 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I/O Input Output Input Output Input I/O I/O I/O Input Input Input Output Output Input Input Input Input Input Input Input Input I/O I/O I/O I/O I/O I/O I/O I/O Input Input Primary Function 12 MHz Oscillator Input 12 MHz Oscillator Output 32 kHz Oscillator Input 32 kHz Oscillator Output Chip general reset Special mode select input with internal pull-up during reset Special mode select input with internal pull-up during reset Special mode select input with internal pull-up during reset JTAG Test Mode Select (with internal weak pull-up) JTAG Test Clock Input (with internal weak pull-up) JTAG Test Data Input (with internal weak pull-up) JTAG Test Data Output NEXUS Ready Output 2.5V Core Logic Power Supply Core Ground 2.5-3.3V I/O Power Supply I/O Ground PLL Analog Power Supply PLL Analog Ground ADC Analog Power Supply ADC Analog Ground ACCESS.bus Clock ACCESS.bus Serial Data ADC Input Channel 0 ADC Input Channel 1 ADC Input Channel 2 ADC Input Channel 3 ADC Input Channel 4 ADC Input Channel 5 ADC Input Channel 6 ADC Input Channel 7 Alternate Name BBCLK None None None None PLLCLK CPUCLK SLOWCLK None None None None None None None None None None None None None None None TSX+ TSY+ TSXTSYMUXOUT0 MUXOUT1 None ADCIN Alternate Function BB reference clock for the RF Interface None None None None PLL Clock Output CPU Clock Output Slow Clock Output None None None None None None None None None None None None None None None Touchscreen X+ contact Touchscreen Y+ contact Touchscreen X- contact Touchscreen Y- contact Analog Multiplexer Output 0 Analog Multiplexer Output 1 None ADC Input (in MUX mode)
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12
CP3CN23
Name VREFP PB[7:0] PC[7:0] A[22:0] SEL0 SEL1 SEL2 SELIO WR0 WR1 RD PE0 PE1 PE2 PE3 PE4
Pins 1 8 8 23 1 1 1 1 1 1 1 1 1 1 1 1
I/O Input I/O I/O Output Output Output Output Output Output Output Output I/O I/O I/O I/O I/O
Primary Function ADC Positive Voltage Reference Generic I/O Generic I/O External Address Bus Bits 0 to 22 Chip Select for Zone 0 Chip Select for Zone 1 Chip Select for Zone 2 Chip Select for I/O Zone External Memory Write Low Byte External Memory Write High Byte External Memory Read Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O
Alternate Name None D[7:0] D[8:15] None None None None None None None None RXD0 TXD0 RTS CTS CKX TB SRFS None
Alternate Function
External Data Bus Bits 0 to 7 External Data Bus Bits 8 to 15 None None None None None None None None UART0 Receive Data Input UART0 Transmit Data Output UART0 Ready-To-Send Output UART0 Clear-To-Send Input UART0 Clock Input Multi Function Timer Port B AAI Receive Frame Sync Non-Maskable Interrupt Input UART Channel 0 Ready-To-Send Output UART Channel 0 Clear-To-Send Input SPI Shift Clock Versatile Timer Channel 1 SPI Master In Slave Out Versatile Timer Channel 2 SPI Master Out Slave In Versatile Timer Channel 3 SPI Slave Select Input Versatile Timer Channel 4 AAI Clock Versatile Timer Channel 5 AAI Frame Synchronization Versatile Timer Channel 6 AAI Transmit Data Output Versatile Timer Channel 7 AAI Receive Data Input Versatile Timer Channel 8 www.national.com
PE5 PE6 PE7 PF0
1 1 1 1
I/O I/O I/O I/O
Generic I/O NMI Generic I/O Generic I/O Generic I/O TIO1 MDIDO CAN1RX CAN1TX MSK
PF1
1
I/O
Generic I/O TIO2 MDODI
PF2
1
I/O
Generic I/O TIO3 MWCS
PF3
1
I/O
Generic I/O TIO4 SCK
PF4
1
I/O
Generic I/O TIO5 SFS
PF5
1
I/O
Generic I/O TIO6 STD
PF6
1
I/O
Generic I/O TIO7 SRD
PF7
1
I/O
Generic I/O TIO8
13
CP3CN23
Name PG0 PG1 PG2 PG3 PG4 PG5 PG6 PG7 PH0
Pins 1 1 1 1 1 1 1 1 1
I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O
Primary Function Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O Generic I/O
Alternate Name None None SRCLK None None None WUI10 TA RXD1 WUI11 TXD1 None None
Alternate Function
AAI Receive Clock None None None Multi-Input Wake-Up Channel 10 Multi Function Timer Port A UART Channel 1 Receive Data Input Multi-Input Wake-Up Channel 11 UART Channel 1 Transmit Data Output Multi-Input Wake-Up Channel 12 UART Channel 2 Receive Data Input Multi-Input Wake-Up Channel 13 UART Channel 2 Transmit Data Output Multi-Input Wake-Up Channel 14 UART Channel 3 Receive Data Input Multi-Input Wake-Up Channel 15 UART Channel 3 Transmit Data Output Multi-Input Wake-Up Channel 16 CAN Receive Input Multi-Input Wake-Up Channel 17 CAN Transmit Output Multi-Input Wake-Up Channel 18 Start Convert Signal to ADC Multi-Input Wake-Up Channel 9
PH1
1
I/O
Generic I/O WUI12 RXD2
PH2
1
I/O
Generic I/O WUI13 TXD2
PH3
1
I/O
Generic I/O WUI14 RXD3
PH4
1
I/O
Generic I/O WUI15 TXD3
PH5
1
I/O
Generic I/O WUI16 CAN0RX
PH6 PH7 PJ0 PJ7
1 1 1 1
I/O I/O I/O I/O
Generic I/O WUI17 Generic I/O Generic I/O Generic I/O WUI9 CAN0TX WUI18 ASYNC
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CP3CN23
5.0
CPU Architecture
The CP3CN23 uses the CR16C third-generation 16-bit When the CFG.SR bit is clear, register pairs are grouped CompactRISC processor core. The CPU implements a Rein the manner used by native CR16C software: (R1,R0), duced Instruction Set Computer (RISC) architecture that al(R2,R1) ... (R11,R10), (R12_L, R11), R12, R13, RA, SP. lows an effective execution rate of up to one instruction per R12, R13, RA, and SP are 32-bit registers for holding adclock cycle. For a detailed description of the CPU16C archidresses greater than 16 bits. tecture, see the CompactRISC CR16C Programmer's Ref- With the recommended calling convention for the architecerence Manual which is available on the National ture, some of these registers are assigned special hardware Semiconductor web site (http://www.nsc.com). and software functions. Registers R0 to R13 are for generalThe CR16C CPU core includes these internal registers: purpose use, such as holding variables, addresses, or index values. The SP register holds a pointer to the program runGeneral-purpose registers (R0-R13, RA, and SP) Dedicated address registers (PC, ISP, USP, and INT- time stack. The RA register holds a subroutine return address. The R12 and R13 registers are available to hold base BASE) addresses used in the index addressing mode. Processor Status Register (PSR) Configuration Register (CFG) The R0-R11, PSR, and CFG registers are 16 bits wide. The R12, R13, RA, SP, ISP and USP registers are 32 bits wide. The PC register is 24 bits wide. Figure 2 shows the CPU registers.
Dedicated Address Registers 15 0 23 31 PC ISPH ISPL USPH USPL INTBASEH INTBASEL General-Purpose Registers 15 0 R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 RA SP DS004
If a general-purpose register is specified by an operation that is 8 bits long, only the lower byte of the register is used; the upper part is not referenced or modified. Similarly, for word operations on register pairs, only the lower word is used. The upper word is not referenced or modified.
5.2
DEDICATED ADDRESS REGISTERS
The CR16C has four dedicated address registers to implement specific functions: the PC, ISP, USP, and INTBASE registers. 5.2.1 Program Counter (PC) Register
Processor Status Register 15 0 PSR Configuration Register 15 0 CFG
31
The 24-bit value in the PC register points to the first byte of the instruction currently being executed. CR16C instructions are aligned to even addresses, therefore the least significant bit of the PC is always 0. At reset, the PC is initialized to 0 or an optional predetermined value. When a warm reset occurs, value of the PC prior to reset is saved in the (R1,R0) general-purpose register pair. 5.2.2 Interrupt Stack Pointer (ISP)
The 32-bit ISP register points to the top of the interrupt stack. This stack is used by hardware to service exceptions (interrupts and traps). The stack pointer may be accessed Figure 2. CPU Registers as the ISP register for initialization. The interrupt stack can Some register bits are designated as "reserved." Software be located anywhere in the CPU address space. The ISP must write a zero to these bit locations when it writes to the cannot be used for any purpose other than the interrupt register. Read operations from reserved bit locations return stack, which is used for automatic storage of the CPU registers when an exception occurs and restoration of these undefined values. registers when the exception handler returns. The interrupt 5.1 GENERAL-PURPOSE REGISTERS stack grows downward in memory. The least significant bit The CompactRISC CPU features 16 general-purpose regis- and the 8 most significant bits of the ISP register are always ters. These registers are used individually as 16-bit oper- 0. ands or as register pairs for operations on addresses 5.2.3 User Stack Pointer (USP) greater than 16 bits. The USP register points to the top of the user-mode proGeneral-purpose registers are defined as R0 through gram stack. Separate stacks are available for user and suR13, RA, and SP. pervisor modes, to support protection mechanisms for Registers are grouped into pairs based on the setting of multitasking software. The processor mode is controlled by the Short Register bit in the Configuration Register the U bit in the PSR register (which is called PSR.U in the (CFG.SR). When the CFG.SR bit is set, the grouping of shorthand convention). Stack grow downward in memory. If register pairs is upward-compatible with the architecture the USP register points to an illegal address (any address of the earlier CR16A/B CPU cores: (R1,R0), (R2,R1) ... greater than 0x00FF_FFFF) and the USP is used for stack (R11,R10), (R12_L, R11), (R13_L, R12_L), (R14_L, access, an IAD trap is taken. R13_L) and SP. (R14_L, R13_L) is the same as (RA,ERA).
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CP3CN23
5.2.4
Interrupt Base Register (INTBASE)
N
The INTBASE register holds the address of the dispatch table for exceptions. The dispatch table can be located anywhere in the CPU address space. When loading the INTBASE register, bits 31 to 24 and bit 0 must written with 0.
5.3
PROCESSOR STATUS REGISTER (PSR)
E
The PSR provides state information and controls operating modes for the CPU. The format of the PSR is shown below. 15 12 11 10 9 I PE 8 7 6 5 F 4 3 2 1 0
Reserved
0NZ
0UL
TC
C
T
L
U
F
Z
The Carry bit indicates whether a carry or borrow occurred after addition or subtraction. 0 - No carry or borrow occurred. 1 - Carry or borrow occurred. The Trace bit enables execution tracing, in which a Trace trap (TRC) is taken after every instruction. Tracing is automatically disabled during the execution of an exception handler. 0 - Tracing disabled. 1 - Tracing enabled. The Low bit indicates the result of the last comparison operation, with the operands interpreted as unsigned integers. 0 - Second operand greater than or equal to first operand. 1 - Second operand less than first operand. The User Mode bit controls whether the CPU is in user or supervisor mode. In supervisor mode, the SP register is used for stack operations. In user mode, the USP register is used instead. User mode is entered by executing the Jump USR instruction. When an exception is taken, the exception handler automatically begins execution in supervisor mode. The USP register is accessible using the Load Processor Register (LPR/LPRD) instruction in supervisor mode. In user mode, an attempt to access the USP register generates a UND trap. 0 - CPU is executing in supervisor mode. 1 - CPU is executing in user mode. The Flag bit is a general condition flag for signalling exception conditions or distinguishing the results of an instruction, among other thing uses. For example, integer arithmetic instructions use the F bit to indicate an overflow condition after an addition or subtraction operation. The Zero bit is used by comparison operations. In a comparison of integers, the Z bit is set if the two operands are equal. If the operands are unequal, the Z bit is cleared. 0 - Source and destination operands unequal. 1 - Source and destination operands equal.
P
I
The Negative bit indicates the result of the last comparison operation, with the operands interpreted as signed integers. 0 - Second operand greater than or equal to first operand. 1 - Second operand less than first operand. The Local Maskable Interrupt Enable bit enables or disables maskable interrupts. If this bit and the Global Maskable Interrupt Enable (I) bit are both set, all interrupts are enabled. If either of these bits is clear, only the nonmaskable interrupt is enabled. The E bit is set by the Enable Interrupts (EI) instruction and cleared by the Disable Interrupts (DI) instruction. 0 - Maskable interrupts disabled. 1 - Maskable interrupts enabled. The Trace Trap Pending bit is used together with the Trace (T) bit to prevent a Trace (TRC) trap from occurring more than once for one instruction. At the beginning of the execution of an instruction, the state of the T bit is copied into the P bit. If the P bit remains set at the end of the instruction execution, the TRC trap is taken. 0 - No trace trap pending. 1 - Trace trap pending. The Global Maskable Interrupt Enable bit is used to enable or disable maskable interrupts. If this bit and the Local Maskable Interrupt Enable (E) bit are both set, all maskable interrupts are taken. If either bit is clear, only the non-maskable interrupt is taken. Unlike the E bit, the I bit is automatically cleared when an interrupt occurs and automatically set upon completion of an interrupt handler. 0 - Maskable interrupts disabled. 1 - Maskable interrupts enabled.
Bits Z, C, L, N, and F of the PSR are referenced from assembly language by the condition code in conditional branch instructions. A conditional branch instruction may cause a branch in program execution, based on the value of one or more of these PSR bits. For example, one of the Bcond instructions, BEQ (Branch EQual), causes a branch if the PSR.Z bit is set. On reset, bits 0 through 11 of the PSR are cleared, except for the PSR.E bit, which is set. On warm reset, the values of each bit before reset are copied into the R2 general-purpose register. Bits 4 and 8 of the PSR have a constant value of 0. Bits 12 through 15 are reserved. In general, status bits are modified only by specific instructions. Otherwise, status bits maintain their values throughout instructions which do not implicitly affect them.
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CP3CN23
5.4
CONFIGURATION REGISTER (CFG)
The CFG register is used to enable or disable various operating modes and to control optional on-chip caches. Because the CP3CN23 does not have cache memory, the cache control bits in the CFG register are reserved. All CFG bits are cleared on reset. 15 Reserved 10 9 8 7 6 0 5 Reserved 2 1 0 0 0
SR ED 0
ED
SR
The Extended Dispatch bit selects whether the size of an entry in the interrupt dispatch table (IDT) is 16 or 32 bits. Each entry holds the address of the appropriate exception handler. When the IDT has 16-bit entries, and all exception handlers must reside in the first 128K of the address space. The location of the IDT is held in the INTBASE register, which is not affected by the state of the ED bit. 0 - Interrupt dispatch table has 16-bit entries. 1 - Interrupt dispatch table has 32-bit entries. The Short Register bit enables a compatibility mode for the CR16B large model. In the CR16C core, registers R12, R13, and RA are extended to 32 bits. In the CR16B large model, only the lower 16 bits of these registers are used, and these "short registers" are paired together for 32-bit operations. In this mode, the (RA, R13) register pair is used as the extended RA register, and address displacements relative to a single register are supported with offsets of 0 and 14 bits in place of the index addressing with these displacements. 0 - 32-bit registers are used. 1 - 16-bit registers are used (CR16B mode).
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CP3CN23
5.5
ADDRESSING MODES
The CR16C CPU core implements a load/store architecture, in which arithmetic and logical instructions operate on register operands. Memory operands are made accessible in registers using load and store instructions. For efficient implementation of I/O-intensive embedded applications, the architecture also provides a set of bit operations that operate on memory operands. The load and store instructions support these addressing modes: register/pair, immediate, relative, absolute, and index addressing. When register pairs are used, the lower bits are in the lower index register and the upper bits are in the higher index register. When the CFG.SR bit is clear, the 32bit registers R12, R13, RA, and SP are also treated as register pairs. References to register pairs in assembly language use parentheses. With a register pair, the lower numbered register pair must be on the right. For example, jump (r5, r4) load $4(r4,r3), (r6,r5) load $5(r12), (r13) The instruction set supports the following addressing modes: In register/pair mode, the operand is held in a general-purpose register, or in a general-purpose register pair. For example, the following instruction adds the contents of the low byte of register r1 to the contents of the low byte of r2, and places the result in the low byte register r2. The high byte of register r2 is not modified. ADDB R1, R2 Immediate In immediate mode, the operand is a conMode stant value which is encoded in the instruction. For example, the following instruction multiplies the value of r4 by 4 and places the result in r4. MULW $4, R4 Relative Mode In relative mode, the operand is addressed using a relative value (displacement) encoded in the instruction. This displacement is relative to the current Program Counter (PC), a general-purpose register, or a register pair. In branch instructions, the displacement is always relative to the current value of the PC Register. For example, the following instruction causes an unconditional branch to an address 10 ahead of the current PC. BR *+10 Register/Pair Mode Index Mode
In another example, the operand resides in memory. Its address is obtained by adding a displacement encoded in the instruction to the contents of register r5. The address calculation does not modify the contents of register r5. LOADW 12(R5), R6 The following example calculates the address of a source operand by adding a displacement of 4 to the contents of a register pair (r5, r4) and loads this operand into the register pair (r7, r6). r7 receives the high word of the operand, and r6 receives the low word. LOADD 4(r5, r4), (r7, r6) In index mode, the operand address is calculated with a base address held in either R12 or R13. The CFG.SR bit must be clear to use this mode. For relative mode operands, the memory address is calculated by adding the value of a register pair and a displacement to the base address. The displacement can be a 14 or 20-bit unsigned value, which is encoded in the instruction. For absolute mode operands, the memory address is calculated by adding a 20-bit absolute address encoded in the instruction to the base address.
In the following example, the operand address is the sum of the displacement 4, the contents of the register pair (r5,r4), and the base address held in register r12. The word at this address is loaded into register r6. LOADW [r12]4(r5, r4), r6 Absolute Mode In absolute mode, the operand is located in memory, and its address is encoded in the instruction (normally 20 or 24 bits). For example, the following instruction loads the byte at address 4000 into the lower 8 bits of register r6. LOADB 4000, r6 For additional information on the addressing modes, see the CompactRISC CR16C Programmer's Reference Manual.
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CP3CN23
5.6
STACKS
5.7
INSTRUCTION SET
A stack is a last-in, first-out data structure for dynamic storage of data and addresses. A stack consists of a block of memory used to hold the data and a pointer to the top of the stack. As more data is pushed onto a stack, the stack grows downward in memory. The CR16C supports two types of stacks: the interrupt stack and program stacks.
Table 4 lists the operand specifiers for the instruction set, and Table 5 is a summary of all instructions. For each instruction, the table shows the mnemonic and a brief description of the operation performed.
In the mnemonic column, the lower-case letter "i" is used to indicate the type of integer that the instruction operates on, either "B" for byte or "W" for word. For example, the notation 5.6.1 Interrupt Stack ADDi for the "add" instruction means that there are two The processor uses the interrupt stack to save and restore forms of this instruction, ADDB and ADDW, which operate the program state during the exception handling. Hardware on bytes and words, respectively. automatically pushes this data onto the interrupt stack before entering an exception handler. When the exception Similarly, the lower-case string "cond" is used to indicate the handler returns, hardware restores the processor state with type of condition tested by the instruction. For example, the data popped from the interrupt stack. The interrupt stack notation Jcond represents a class of conditional jump instructions: JEQ for Jump on Equal, JNE for Jump on Not pointer is held in the ISP register. Equal, etc. For detailed information on all instructions, see 5.6.2 Program Stack the CompactRISC CR16C Programmer's Reference ManuThe program stack is normally used by software to save and al. restore register values on subroutine entry and exit, hold loTable 4 Key to Operand Specifiers cal and temporary variables, and hold parameters passed between the calling routine and the subroutine. The only Operand Specifier Description hardware mechanisms which operate on the program stack are the PUSH, POP, and POPRET instructions. abs Absolute address 5.6.3 User and Supervisor Stack Pointers disp imm Iposition Rbase Rdest Rindex RPbase, RPbasex RPdest RPlink Rposition Rproc Rprocd RPsrc RPtarget Rsrc, Rsrc1, Rsrc2 To support multitasking operating systems, support is provided for two program stack pointers: a user stack pointer and a supervisor stack pointer. When the PSR.U bit is clear, the SP register is used for all program stack operations. This is the default mode when the user/supervisor protection mechanism is not used, and it is the supervisor mode when protection is used. When the PSR.U bit is set, the processor is in user mode, and the USP register is used as the program stack pointer. User mode can only be entered using the JUSR instruction, which performs a jump and sets the PSR.U bit. User mode is exited when an exception is taken and re-entered when the exception handler returns. In user mode, the LPRD instruction cannot be used to change the state of processor registers (such as the PSR). Displacement (numeric suffix indicates number of bits) Immediate operand (numeric suffix indicates number of bits) Bit position in memory Base register (relative mode) Destination register Index register Base register pair (relative mode) Destination register pair Link register pair Bit position in register 16-bit processor register 32-bit processor register Source register pair Target register pair Source register
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CP3CN23
Table 5 Instruction Set Summary Mnemonic MOVi MOVXB MOVZB MOVXW MOVZW MOVD Operands Rsrc/imm, Rdest Rsrc, Rdest Rsrc, Rdest Rsrc, RPdest Rsrc, RPdest imm, RPdest RPsrc, RPdest ADD[U]i ADDCi ADDD MACQWa MACSWa MACUWa MULi MULSB MULSW MULUW SUBi SUBD SUBCi CMPi CMPD BEQ0i BNE0i ANDi ANDD ORi ORD Scond XORi XORD ASHUi Rsrc/imm, Rdest Rsrc/imm, Rdest RPsrc/imm, RPdest Rsrc1, Rsrc2, RPdest Rsrc1, Rsrc2, RPdest Rsrc1, Rsrc2, RPdest Rsrc/imm, Rdest Rsrc, Rdest Rsrc, RPdest Rsrc, RPdest Rsrc/imm, Rdest RPsrc/imm, RPdest Rsrc/imm, Rdest Rsrc/imm, Rdest RPsrc/imm, RPdest Rsrc, disp Rsrc, disp Rsrc/imm, Rdest RPsrc/imm, RPdest Rsrc/imm, Rdest RPsrc/imm, RPdest Rdest Rsrc/imm, Rdest RPsrc/imm, RPdest Rsrc/imm, Rdest Move Move with sign extension Move with zero extension Move with sign extension Move with zero extension Move immediate to register-pair Move between register-pairs Add Add with carry Add with RP or immediate. Multiply signed Q15: RPdest := RPdest + (Rsrc1 x Rsrc2) Multiply signed and add result: RPdest := RPdest + (Rsrc1 x Rsrc2) Multiply unsigned and add result: RPdest := RPdest + (Rsrc1 x Rsrc2) Multiply: Rdest(8) := Rdest(8) x Rsrc(8)/imm Rdest(16) := Rdest(16) x Rsrc(16)/imm Multiply: Rdest(16) := Rdest(8) x Rsrc(8) Multiply: RPdest := RPdest(16) x Rsrc(16) Multiply: RPdest := RPdest(16) x Rsrc(16); Subtract: (Rdest := Rdest - Rsrc/imm) Subtract: (RPdest := RPdest - RPsrc/imm) Subtract with carry: (Rdest := Rdest - Rsrc/imm) Compare Rdest - Rsrc/imm Compare RPdest - RPsrc/imm Compare Rsrc to 0 and branch if EQUAL Compare Rsrc to 0 and branch if NOT EQUAL Logical AND: Rdest := Rdest & Rsrc/imm Logical AND: RPdest := RPsrc & RPsrc/imm Logical OR: Rdest := Rdest | Rsrc/imm Logical OR: Rdest := RPdest | RPsrc/imm Save condition code as boolean Logical exclusive OR: Rdest := Rdest ^ Rsrc/imm Logical exclusive OR: Rdest := RPdest ^ RPsrc/imm Arithmetic left/right shift Description
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CP3CN23
Table 5 Instruction Set Summary Mnemonic ASHUD LSHi LSHD SBITi Operands Rsrc/imm, RPdest Rsrc/imm, Rdest Rsrc/imm, RPdest Iposition, disp(Rbase) Iposition, disp(RPbase) Iposition, (Rindex)disp(RPbasex) Iposition, abs Iposition, (Rindex)abs CBITi Iposition, disp(Rbase) Iposition, disp(RPbase) Iposition, (Rindex)disp(RPbasex) Iposition, abs Iposition, (Rindex)abs TBIT TBITi Rposition/imm, Rsrc Iposition, disp(Rbase) Iposition, disp(RPbase) Iposition, (Rindex)disp(RPbasex) Iposition, abs Iposition, (Rindex)abs LPR LPRD SPR SPRD Bcond Rsrc, Rproc RPsrc, Rprocd Rproc, Rdest Rprocd, RPdest disp9 disp17 disp24 BAL BR RPlink, disp24 disp9 disp17 disp24 EXCP Jcond JAL vector RPtarget RA, RPtarget, RPlink, RPtarget JUMP JUSR RPtarget RPtarget Jump Jump and set PSR.U Trap (vector) Conditional Jump to a large address Jump and link to a large address Branch and link Branch Load processor register Load double processor register Store processor register Store 32-bit processor register Conditional branch Test a bit in a register Test a bit in memory Clear a bit in memory Description Arithmetic left/right shift Logical left/right shift Logical left/right shift Set a bit in memory (Because this instruction treats the destination as a readmodify-write operand, it not be used to set bits in writeonly registers.)
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CP3CN23
Table 5 Instruction Set Summary Mnemonic RETX PUSH POP POPRET LOADi imm, Rsrc, RA imm, Rdest, RA imm, Rdest, RA disp(Rbase), Rdest abs, Rdest (Rindex)abs, Rdest (Rindex)disp(RPbasex), Rdest disp(RPbase), Rdest LOADD disp(Rbase), Rdest abs, Rdest (Rindex)abs, Rdest (Rindex)disp(RPbasex), Rdest disp(RPbase), Rdest STORi Rsrc, disp(Rbase) Rsrc, disp(RPbase) Rsrc, abs Rsrc, (Rindex)disp(RPbasex) Rsrc, (Rindex)abs STORD RPsrc, disp(Rbase) RPsrc, disp(RPbase) RPsrc, abs RPsrc, (Rindex)disp(RPbasex) RPsrc, (Rindex)abs STOR IMM imm4, disp(Rbase) imm4, disp(RPbase) imm4, (Rindex)disp(RPbasex) imm4, abs imm4, (Rindex)abs LOADM LOADMP STORM imm3 imm3 STORM imm3 Load 1 to 8 registers (R2-R5, R8-R11) from memory starting at (R0) Load 1 to 8 registers (R2-R5, R8-R11) from memory starting at (R1, R0) Store 1 to 8 registers (R2-R5, R8-R11) to memory starting at (R2) Operands Return from exception Push "imm" number of registers on user stack, starting with Rsrc and possibly including RA Restore "imm" number of registers from user stack, starting with Rdest and possibly including RA Restore registers (similar to POP) and JUMP RA Load (register relative) Load (absolute) Load (absolute index relative) Load (register relative index) Load (register pair relative) Load (register relative) Load (absolute) Load (absolute index relative) Load (register pair relative index) Load (register pair relative) Store (register relative) Store (register pair relative) Store (absolute) Store (register pair relative index) Store (absolute index) Store (register relative) Store (register pair relative) Store (absolute) Store (register pair index relative) Store (absolute index relative) Store unsigned 4-bit immediate value extended to operand length in memory Description
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CP3CN23
Table 5 Instruction Set Summary Mnemonic STORMP DI EI EIWAIT NOP WAIT imm3 Operands Description Store 1 to 8 registers (R2-R5, R8-R11) to memory starting at (R7,R6) Disable maskable interrupts Enable maskable interrupts Enable maskable interrupts and wait for interrupt No operation Wait for interrupt
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CP3CN23
6.0
Memory
are reserved and must not be read or written. The BIU zones are regions of the address space that share the same control bits in the Bus Interface Unit (BIU).
The CP3CN23 supports a uniform 16M-byte linear address space. Table 6 lists the types of memory and peripherals that occupy this memory space. Unlisted address ranges
Table 6 CP3CN23 Memory Map Start Address 00 0000h 04 0000h 0D 0000h 0D 2000h 0E 0000h 0E 8000h 0E F000h 0E F140h 0E F200h 0E F320h 10 0000h 40 0000h 80 0000h FF 0000h FF F200h FF F600h FF FB00h FF FC00h End Address 03 FFFFh 0C FFFFh 0D 1FFFh 0D FFFFh 0E 7FFFh 0E EFFFh 0E F13Fh 0E F1FFh 0E F33Fh 0F FFFFh 3F FFFFh 7F FFFFh FE FFFFh FF F1FFh FF F5FFh FF FAFFh FF FBFFh FF FFFFh Size in Bytes 256K 576K 8K 56K 32K 28K 320 192 320 67K 3072K 4096K 8128K 61952 1K 1280 256 1K Description On-chip Flash Program Memory, including Boot Memory Reserved On-chip Flash Data Memory Reserved System RAM Reserved CAN0 Buffers and Registers Reserved CAN1 Buffers and Registers Reserved Reserved External Memory Zone 1 External Memory Zone 2 Reserved Peripherals and Other I/O Ports BIU, DMA, Flash interfaces I/O Expansion Peripherals and Other I/O Ports N/A IN/A I/O Zone N/A Static Zone 1 Static Zone 2 N/A BIU Zone Static Zone 0 (mapped internally in IRE and ERE mode; mapped to the external bus in DEV mode)
6.1
OPERATING ENVIRONMENT
The operating environment controls whether external memory is supported and whether the reset vector jumps to a code space intended to support In-System Programming (ISP). Up to 12M of external memory space is available. The operating mode of the device is controlled by the states on the ENV[2:0] pins at reset and the states of the EMPTY bits in the Protection Word, as shown in Table 7. Internal pullups on the ENV[2:0] pins select IRE mode or ISP mode if these pins are allowed to float. When ENV[2:0] = 111b, IRE mode is selected unless the EMPTY bits in the Protection word indicate that the program flash memory is empty (unprogrammed), in which case ISP mode is selected. When ENV[2:0] = 011b, ERE mode is selected unless the EMPTY bits indicate that the program flash memory is empty, in which case ISP mode is selected. When ENV[2:0] = 110b, ISP mode is selected without regard to the states of the EMPTY bits. See Section 8.4.2 for more details.
In the DEV environment, the on-chip flash memory is disabled, and the corresponding region of the address space is mapped to external memory. DEVINT mode is equivalent to DEV mode but maps static memory zone 0 to the on-chip memory.
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CP3CN23
6.4
Table 7 Operating Environment Selection ENV[2:0] EMPTY 111 011 000 001 110 111 011 No No N/A N/A N/A Yes Yes Operating Environment Internal ROM enabled (IRE) mode External ROM enabled (ERE) mode Development (DEV) mode Development (DEVINT) mode with internal memory In-System-Programming (ISP) mode In-System-Programming (ISP) mode In-System-Programming (ISP) mode
BIU CONTROL REGISTERS
The BIU has a set of control registers that determine how many wait cycles and hold cycles are to be used for accessing memory. During initialization of the system, these registers should be programmed with appropriate values so that the minimum allowable number of cycles is used. This number varies with the clock frequency. There are five BIU control registers, as listed in Table 8. These registers control the bus cycle configuration used for accessing the various on-chip memory types. Table 8 Bus Control Registers Name BCFG IOCFG SZCFG0 SZCFG1 SZCFG2 6.4.1 Address FF F900h FF F902h FF F904h FF F906h FF F908h Description BIU Configuration Register I/O Zone Configuration Register Static Zone 0 Configuration Register Static Zone 1 Configuration Register Static Zone 2 Configuration Register
6.2
BUS INTERFACE UNIT (BIU)
The BIU controls the interface between the CPU core bus and those on-chip modules which are mapped into BIU zones. These on-chip modules are the flash program memory and the I/O zone. The BIU controls the configured parameters for bus access (such as the number of wait states for memory access) and issues the appropriate bus signals for the requested access.
6.3
BUS CYCLES
There are four types of data transfer bus cycles: Normal read Fast read Early write Late write The type of data cycle used in a particular transaction depends on the type of CPU operation (a write or a read), the type of memory or I/O being accessed, and the access type programmed into the BIU control registers (early/late write or normal/fast read). For read operations, a basic normal read takes two clock cycles, and a fast-read bus cycle takes one clock cycle. Normal read bus cycles are enabled by default after reset. For write operations, a basic late-write bus cycle takes two clock cycles, and a basic early-write bus cycle takes three clock cycles. Early-write bus cycles are enabled by default after reset. However, late-write bus cycles are needed for ordinary write operations, so this configuration must be changed by software (see Section 6.4.1). In certain cases, one or more additional clock cycles are added to a bus access cycle. There are two types of additional clock cycles for ordinary memory accesses, called internal wait cycles (TIW) and hold (Thold) cycles. A wait cycle is inserted in a bus cycle just after the memory address has been placed on the address bus. This gives the accessed memory more time to respond to the transaction request. A hold cycle is inserted at the end of a bus cycle. This holds the data on the data bus for an extended number of clock cycles. BIU Configuration Register (BCFG) The BCFG register is a byte-wide, read/write register that selects early-write or late-write bus cycles. At reset, the register is initialized to 07h. The register format is shown below. 7 Reserved 3 2 1 1 1 0 EWR
EWR
The Early Write bit controls write cycle timing. 0 - Late-write operation (2 clock cycles to write). 1 - Early-write operation.
At reset, the BCFG register is initialized to 07h, which selects early-write operation. However, late-write operation is required for normal device operation, so software must change the register value to 06h. Bits 1 and 2 of this register must always be set when writing to this register.
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6.4.2
I/O Zone Configuration Register (IOCFG)
6.4.3
Static Zone 0 Configuration Register (SZCFG0)
The IOCFG register is a word-wide, read/write register that controls the timing and bus characteristics of accesses to the 256-byte I/O Zone memory space (FF FB00h to FF FBFFh). The registers associated with Port B and Port C reside in the I/O memory array. At reset, the register is initialized to 069Fh. The register format is shown below. 7 BW 6 5 4 3 2 WAIT 0
The SZCFG0 register is a word-wide, read/write register that controls the timing and bus characteristics of Zone 0 memory accesses. Zone 0 is used for the on-chip flash memory (including the boot area, program memory, and data memory). At reset, the register is initialized to 069Fh. The register format is shown below. 7 BW 6 WBR 5 RBE 4 3 2 WAIT 0
Reserved
HOLD
HOLD
15 Reserved
10
9 IPST
8 Res. 15 Reserved 12 11 FRE 10 9 8 Res. IPRE IPST
WAIT
HOLD
BW
IPST
The Memory Wait Cycles field specifies the number of TIW (internal wait state) clock cycles added for each memory access, ranging from 000 binary for no additional TIW wait cycles to 111 binary for seven additional TIW wait cycles. The Memory Hold Cycles field specifies the number of Thold clock cycles used for each memory access, ranging from 00b for no Thold cycles to 11b for three Thold clock cycles. The Bus Width bit defines the bus width of the IO Zone. 0 - 8-bit bus width. 1 - 16-bit bus width (default) The Post Idle bit controls whether an idle cycle follows the current bus cycle, when the next bus cycle accesses a different zone. No idle cycles are required for on-chip accesses. 0 - No idle cycle (recommended). 1 - Idle cycle.
WAIT
HOLD
RBE
WBR
BW
FRE
IPST
The Memory Wait field specifies the number of TIW (internal wait state) clock cycles added for each memory access, ranging from 000b for no additional TIW wait cycles to 111b for seven additional TIW wait cycles. These bits are ignored if the SZCFG0.FRE bit is set. The Memory Hold field specifies the number of Thold clock cycles used for each memory access, ranging from 00b for no Thold cycles to 11b for three Thold clock cycles. These bits are ignored if the SZCFG0.FRE bit is set. The Read Burst Enable enables burst cycles on 16-bit reads from 8-bit bus width regions of the address space. Because the flash program memory is required to be 16-bit bus width, the RBE bit is a don't care bit. This bit is ignored when the SZCFG0.FRE bit is set. 0 - Burst read disabled. 1 - Burst read enabled. The Wait on Burst Read bit controls if a wait state is added on burst read transaction. This bit is ignored, when SZCFG0.FRE bit is set or when SZCFG0.RBE is clear. 0 - No TBW on burst read cycles. 1 - One TBW on burst read cycles. The Bus Width bit controls the bus width of the zone. The flash program memory must be configured for 16-bit bus width. 0 - 8-bit bus width. 1 - 16-bit bus width (required). The Fast Read Enable bit controls whether fast read bus cycles are used. A fast read operation takes one clock cycle. A normal read operation takes at least two clock cycles. 0 - Normal read cycles. 1 - Fast read cycles. The Post Idle bit controls whether an idle cycle follows the current bus cycle, when the next bus cycle accesses a different zone. No idle cycles are required for on-chip accesses. 0 - No idle cycle (recommended). 1 - Idle cycle inserted.
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IPRE
The Preliminary Idle bit controls whether an idle cycle is inserted prior to the current bus cycle, when the new bus cycle accesses a different zone. No idle cycles are required for onchip accesses. 0 - No idle cycle (recommended). 1 - Idle cycle inserted. Static Zone 1 Configuration Register (SZCFG1)
IPST
IPRE
6.4.4
The SZCFG1 register is a word-wide, read/write register that controls the timing and bus characteristics for off-chip accesses selected with the SEL1 output signal. At reset, the register is initialized to 069Fh. The register format is shown below. 7 BW 6 WBR 5 RBE 4 3 2 WAIT 0
The Post Idle bit controls whether an idle cycle follows the current bus cycle, when the next bus cycle accesses a different zone. 0 - No idle cycle. 1 - Idle cycle inserted. The Preliminary Idle bit controls whether an idle cycle is inserted prior to the current bus cycle, when the new bus cycle accesses a different zone. 0 - No idle cycle. 1 - Idle cycle inserted. Static Zone 2 Configuration Register (SZCFG2)
6.4.5
The SZCFG2 register is a word-wide, read/write register that controls the timing and bus characteristics for off-chip accesses selected with the SEL2 output signal. At reset, the register is initialized to 069Fh. The register format is shown below. 7 BW 6 WBR 5 RBE 4 3 2 WAIT 0
HOLD
15 Reserved
12
11 FRE
10
9
8 Res.
IPRE IPST
HOLD
WAIT
HOLD
RBE
WBR
BW
FRE
The Memory Wait field specifies the number of TIW (internal wait state) clock cycles added for each memory access, ranging from 000b for no additional TIW wait cycles to 111b for seven additional TIW wait cycles. These bits are ignored if the SZCFG1.FRE bit is set. The Memory Hold field specifies the number of Thold clock cycles used for each memory access, ranging from 00b for no Thold cycles to 11b for three Thold clock cycles. These bits are ignored if the SZCFG1.FRE bit is set. The Read Burst Enable enables burst cycles on 16-bit reads from 8-bit bus width regions of the address space. This bit is ignored when the SZCFG1.FRE bit is set or the SZCFG1.BW is clear. 0 - Burst read disabled. 1 - Burst read enabled. The Wait on Burst Read bit controls if a wait state is added on burst read transaction. This bit is ignored, when SZCFG1.FRE bit is set or when SZCFG1.RBE is clear. 0 - No TBW on burst read cycles. 1 - One TBW on burst read cycles. The Bus Width bit controls the bus width of the zone. 0 - 8-bit bus width. 1 - 16-bit bus width. The Fast Read Enable bit controls whether fast read bus cycles are used. A fast read operation takes one clock cycle. A normal read operation takes at least two clock cycles. 0 - Normal read cycles. 1 - Fast read cycles.
15 Reserved
12
11 FRE
10
9
8 Res.
IPRE IPST
WAIT
HOLD
RBE
WBR
BW
The Memory Wait field specifies the number of TIW (internal wait state) clock cycles added for each memory access, ranging from 000b for no additional TIW wait cycles to 111b for seven additional TIW wait cycles. These bits are ignored if the SZCFG2.FRE bit is set. The Memory Hold field specifies the number of Thold clock cycles used for each memory access, ranging from 00b for no Thold cycles to 11b for three Thold clock cycles. These bits are ignored if the SZCFG2.FRE bit is set. The Read Burst Enable enables burst cycles on 16-bit reads from 8-bit bus width regions of the address space. This bit is ignored when the SZCFG2.FRE bit is set or the SZCFG2.BW is clear. 0 - Burst read disabled. 1 - Burst read enabled. The Wait on Burst Read bit controls if a wait state is added on burst read transaction. This bit is ignored, when SZCFG2.FRE bit is set or when SZCFG2.RBE is clear. 0 - No TBW on burst read cycles. 1 - One TBW on burst read cycles. The Bus Width bit controls the bus width of the zone. 0 - 8-bit bus width. 1 - 16-bit bus width.
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FRE
IPST
IPRE
The Fast Read Enable bit controls whether fast read bus cycles are used. A fast read operation takes one clock cycle. A normal read operation takes at least two clock cycles. 0 - Normal read cycles. 1 - Fast read cycles. The Post Idle bit controls whether an idle cycle follows the current bus cycle, when the next bus cycle accesses a different zone. 0 - No idle cycle. 1 - Idle cycle inserted. The Preliminary Idle bit controls whether an idle cycle is inserted prior to the current bus cycle, when the new bus cycle accesses a different zone. 0 - No idle cycle. 1 - Idle cycle inserted.
6.5
WAIT AND HOLD STATES
The number of wait cycles and hold cycles inserted into a bus cycle depends on whether it is a read or write operation, the type of memory or I/O being accessed, and the control register settings. 6.5.1 Flash Program/Data Memory
When the CPU accesses the Flash program and data memory (address ranges 000000h-03FFFFh and 0E0000h- 0E1FFFh), the number of added wait and hold cycles depends on the type of access and the BIU register settings. In fast-read mode (SZCFG0.FRE=1), a read operation is a single cycle access. This limits the maximum CPU operating frequency to 24 MHz. For a read operation in normal-read mode (SZCFG0.FRE=0), the number of inserted wait cycles is specified in the SZCFG0.WAIT field. The total number of wait cycles is the value in the WAIT field plus 1, so it can range from 1 to 8. The number of inserted hold cycles is specified in the SCCFG0.HOLD field, which can range from 0 to 3. For a write operation in fast read mode (SZCFG0.FRE=1), the number of inserted wait cycles is 1. No hold cycles are used. For a write operation normal read mode (SZCFG0.FRE=0), the number of wait cycles is equal to the value written to the SZCFG0.WAIT field plus 1 (in the late write mode) or 2 (in the early write mode). The number of inserted hold cycles is equal to the value written to the SCCFG0.HOLD field, which can range from 0 to 3. 6.5.2 RAM Memory
Read and write accesses to on-chip RAM is performed within a single cycle, without regard to the BIU settings. The RAM address is in the range of 0E 0000h-0E 7FFFh and 0E 8000h-0E 91FFh. 6.5.3 Access to Peripherals
When the CPU accesses on-chip peripherals in the range of 0E F000h-0E F1FFh and FF 0000h-FF FBFFh, one wait cycle and one preliminary idle cycle is used. No hold cycles are used. The IOCFG register determines the access timing for the address range FF FB00h-FF FBFFh.
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7.0
System Configuration Registers
7.1
The system configuration registers control and provide status for certain aspects of device setup and operation, such as indicating the states sampled from the ENV[2:0] inputs. The system configuration registers are listed in Table 9. Table 9 Name MCFG MSTAT System Configuration Registers Address FF F910h FF F914h Description Module Configuration Register Module Status Register
MODULE CONFIGURATION REGISTER (MCFG)
The MCFG register is a byte-wide, read/write register that selects the clock output features of the device. The register must be written in active mode only, not in power save, HALT, or IDLE mode. However, the register contents are preserved during all power modes. The MCFG register format is shown below. 7 Res. 6 5 4 3 2 1 0
MEM_IO_ MISC_IO_ SCLK MCLK PLLCLK EXI Res. SPEED SPEED OE OE OE OE
EXIOE
The EXIOE bit controls whether the external bus is enabled in the IRE environment for implementing the I/O Zone (FF FB00h-FF FBFFh). 0 - External bus disabled. 1 - External bus enabled. PLLCLKOE The PLLCLKOE bit controls whether the PLL clock is driven on the ENV0/PLLCLK pin. 0 - ENV0/PLLCLK pin is high impedance. 1 - PLL clock driven on the ENV0/PLLCLK pin. MCLKOE The MCLKOE bit controls whether the Main Clock is driven on the ENV1/CPUCLK pin. 0 - ENV1/CPUCLK pin is high impedance. 1 - Main Clock is driven on the ENV1/CPUCLK pin. SCLKOE The SCLKOE bit controls whether the Slow Clock is driven on the ENV2/SLOWCLK pin. 0 - ENV2/SLOWCLK pin is high impedance. 1 - Slow Clock is driven on the ENV2/SLOWCLK pin. MISC_IO_SPEED The MISC_IO_SPEED bit controls the slew rate of the output drivers for the ENV[2:0], RDY, and TDO pins. To minimize noise, the slow slew rate is recommended. 0 - Fast slew rate. 1 - Slow slew rate. MEM_IO_SPEED The MEM_IO_SPEED bit controls the slew rate of the output drivers for the A[22:0], RD, SEL[2:0], SELIO, WR[1:0], PB[7:0], and PC[7:0] pins. Memory speeds for the CP3CN23 are characterized with fast slew rate. Slow slew rate reduces the available memory access time by 5 ns. 0 - Fast slew rate. 1 - Slow slew rate.
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7.2
MODULE STATUS REGISTER (MSTAT)
7.3
The MSTAT register is a byte-wide, read-only register that indicates the general status of the device. The MCFG regis- The SWRESET register is a byte-wide, write-only register ter format is shown below. which provides a mechanism for software to initiate a reset into ISP mode without regard to the status of the EMPTY bits in the flash protection word. This form of reset is only al7 6 5 4 3 2 0 lowed when all of the following conditions are true: ISPRST WDRST Res. DPGMBUSY PGMBUSY OENV2:0 The device is in IRE or ERE mode BOOTAREA is defined (has a value other than 1111b) in the Protection Word (see Section 8.4.2 for more details). OENV2:0 The Operating Environment bits hold the ISPE is set in the flash protection word, indicating that states sampled from the ENV[2:0] input pins there is ISP code in the flash at reset. These states are controlled by external hardware at reset and are held constant in the register until the next reset. PGMBUSY The Flash Programming Busy bit is automatically set when either the program memory or the data memory is being programmed or erased. It is clear when neither of the memories is busy. When this bit is set, software must not attempt to program or erase either of these two memories. This bit is a copy of the FMBUSY bit in the FMSTAT register. 0 - Flash memory is not busy. 1 - Flash memory is busy. DPGMBUSY The Data Flash Programming Busy indicates that the flash data memory is being erased or a pipelined programming sequence is currently ongoing. Software must not attempt to perform any write access to the flash program memory at this time, without also polling the FSMSTAT.FMFULL bit in the flash memory interface. The DPGMBUSY bit is a copy of the FMBUSY bit in the FSMSTAT register. 0 - Flash data memory is not busy. 1 - Flash data memory is busy. WDRST The Watchdog Reset bit indicates that a Watchdog timer reset has occurred. Write a 1 to this bit to clear it. Power-on reset also clears this bit. 0 - No Watchdog timer reset has occurred since this bit was last cleared. 1 - A Watchdog timer reset has occurred since this bit was last cleared. ISPRST The Software ISP Reset bit indicates that a software ISP reset has occurred since the bit was last cleared. This bit is cleared by a SWRESET(CLR) sequence or a power-on reset. 0 - No software ISP reset has occurred since this bit was last cleared. 1 - A software ISP reset has occurred since this bit was last cleared. To initiate a reset under these conditions, it is necessary to write the value E1h to the SWRESET register, followed within 127 clock cycles by the value 3Eh. The reset then follows immediately. This sequence is called SWRESET(ISP). Once the device has been reset into ISP mode by SWRESET(ISP), any subsequent reset (other than internal or external power-on reset) will cause the part to reset into ISP mode because the EMPTY bits in the Protection Word continue to be ignored. A second set of special values written to the SWRESET register will cause a reset out of ISP mode (whether or not the device is currently in ISP mode). This can be used as a simple software reset. In this case, no conditions are checked. To initiate reset out of ISP mode, write the value E1h to the SWRESET register, followed within 127 clock cycles by the value 0Eh. The reset then follows immediately. This sequence is called SWRESET(CLR). This reset also cancels the effect of any previous SWRESET(ISP), so subsequent resets will check the EMPTY bits to determine whether to enter ISP mode. The ISP reset behaves similarly to the Watchdog reset, for example, if the flash interface is busy when reset is asserted, the reset to the clock module is delayed until the flash operations are completed.
SOFTWARE RESET REGISTER (SWRESET)
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8.0
Flash Memory
The flash memory consists of the flash program memory and the flash data memory. The flash program memory is further divided into the Boot Area and the Code Area.
default (after reset) all bits in the FM0WER, FM1WER, and FSM0WER registers are cleared, which disables write access by the CPU to all sections. Write access to a section is A special protection scheme is applied to the lower portion enabled by setting the corresponding write enable bit. After of the flash program memory, called the Boot Area. The completing a programming or erase operation, software Boot Area always starts at address 0 and ranges up to a should clear all write enable bits to protect the flash program programmable end address. The maximum boot area ad- memory against any unintended writes. dress which can be selected is 00 77FFh. The intended use 8.1.2 Global Protection of this area is to hold In-System-Programming (ISP) rouThe WRPROT field in the Protection Word controls global tines or essential application routines. The Boot Area is alwrite protection. The Protection Word is located in a special ways protected against CPU write access, to avoid flash memory outside of the CPU address space. If a majorunintended modifications. ity of the bits in the 3-bit WRPROT field are clear, write proThe Code Area is intended to hold the application code and tection is enabled. Enabling this mode prevents the CPU constant data. The Code Area begins with the next byte af- from writing to flash memory. ter the Boot Area. Table 10 summarizes the properties of The RDPROT field in the Protection Word controls global the regions of flash memory mapped into the CPU address read protection. If a majority of the bits in the 3-bit RDPROT space. field are clear, read protection is enabled. Enabling this Table 10 Flash Memory Areas mode prevents reading by an external debugger through the serial debug interface or by an external flash programmer. Read Area Address Range Write Access CPU read access is not affected by the RDPROT bits. Access
8.2
FLASH MEMORY ORGANIZATION
Boot Area
0-BOOTAREA - 1
Yes
No Write access only if section write enable bit is set and global write protection is disabled. Write access only if section write enable bit is set and global write protection is disabled.
Code BOOTAREA-03 FFFFh Area
Yes
Each of the flash memories are divided into main blocks and information blocks. The main blocks hold the code or data used by application software. The information blocks hold factory parameters, protection settings, and other devicespecific data. The main blocks are mapped into the CPU address space. The information blocks are accessed indirectly through a register-based interface. Separate sets of registers are provided for accessing flash program memory (FM registers) and flash data memory (FSM registers). The flash program memory consists of two main blocks and two data blocks, as shown in Table 11. The flash data memory consists of one main block and one information block. Table 11 Flash Memory Blocks Name Main Block 0 Address Range 00 0000h-01 FFFFh (CPU address space) 000h-07Fh (address register) 02 0000h-03 FFFFh (CPU address space) 080h-0FFh (address register) 0D 0000h-0D 1FFFh (CPU address space) 000h-07Fh (address register) Function Flash Program Memory Function Word, Factory Parameters Flash Program Memory Protection Word, User Data Flash Data Memory User Data
Data Area
0E 0000h-0E 1FFFh
Yes
8.1
FLASH MEMORY PROTECTION
Information Block 0 Main Block 1 Information Block 1 Main Block 2 Information Block 2
The memory protection mechanisms provide both global and section-level protection. Section-level protection against CPU writes is applied to individual 8K-byte sections of the flash program memory and 512-byte sections of the flash data memory. Section-level protection is controlled through read/write registers mapped into the CPU address space. Global write protection is applied at the device level, to disable flash memory writes by the CPU. Global write protection is controlled by the encoding of bits stored in the flash memory array. 8.1.1 Section-Level Protection
Each bit in the Flash Memory Write Enable (FM0WER and FM1WER) registers enables or disables write access to a corresponding section of flash program memory. Write access to the flash data memory is controlled by the bits in the Flash Slave Memory Write Enable (FSM0WER) register. By
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8.2.1
Main Block 0 and 1
8.2.4
Main Block 2
Main Block 0 and Main Block 1 hold the 256K-byte program space, which consists of the Boot Area and Code Area. Each block consists of sixteen 8K-byte sections. Write access by the CPU to Main Block 0 and Main Block 1 is controlled by the corresponding bits in the FM0WER and FM1WER registers, respectively. The least significant bit in each register controls the section at the lowest address. 8.2.2 Information Block 0
Main Block 2 holds the 8K-byte data area, which consists of sixteen 512-byte sections. Write access by the CPU to Main Block 2 is controlled by the corresponding bits in the FSM0WER register. The least significant bit in the register controls the section at the lowest address. 8.2.5 Information Block 2
Information Block 0 contains 128 bytes, of which one 16-bit word has a dedicated function, called the Function Word. The Function Word resides at address 07Eh. The remaining Information Block 0 locations are used to hold factory parameters. Software only has read access to Information Block 0 through a register-based interface. The Function Word and the factory parameters are protected against CPU writes. Table 12 shows the structure of Information Block 0. Table 12 Information Block 0 Name Function Word Other (Used for Factory Parameters) 8.2.3 Address Range 07Eh-07Fh Yes 000h-07Dh No Read Access Write Access
Information Block 2 contains 128 bytes, which can be used to store user data. The CPU can always read Information Block 2. The CPU can write Information Block 2 only when global write protection is disabled. Erasing Information Block 2 also erases Main Block 2.
8.3
FLASH MEMORY OPERATIONS
Flash memory programming (erasing and writing) can be performed on the flash data memory while the CPU is executing out of flash program memory. Although the CPU can execute out of flash data memory, it cannot erase or write the flash program memory while executing from flash data memory. To erase or write the flash program memory, the CPU must be executing from the on-chip static RAM or offchip memory. An erase operation is required before programming. An erase operation sets all of the bits in the erased region. A programming operation clears selected bits. The programming mechanism is pipelined, so that a new write request can be loaded while a previous request is in progress. When the FMFULL bit in the FMSTAT or FSMSTAT register is clear, the pipeline is ready to receive a new request. New requests may be loaded after checking only the FMFULL bit. 8.3.1 Main Block Read
Information Block 1
Information Block 1 contains 128 bytes, of which one 16-bit word has a dedicated function, called the Protection Word. The Protection Word resides at address 0FEh. It controls the global protection mechanisms and the size of the Boot Area. The Protection Word can be written by the CPU, however the changes only become valid after the next device reset. The remaining Information Block 1 locations can be used to store other user data. Erasing Information Block 1 also erases Main Block 1. Table 13 shows the structure of the Information Block 1. Table 13 Information Block 1 Name Protection Word Other (User Data) Address Range 0FEh-0FFh Yes 080h-0FDh Read Access Write Access Write access only if section write enable bit is set and global write protection is disabled.
Read accesses from flash program memory can only occur when the flash program memory is not busy from a previous write or erase operation. Read accesses from the flash data memory can only occur when both the flash program memory and the flash data memory are not busy. Both byte and word read operations are supported. 8.3.2 Information Block Read
Information block data is read through the register-based interface. Only word read operations are supported and the read address must be word-aligned (LSB = 0). The following steps are used to read from an information block: 1. Load the word address in the Flash Memory Information Block Address (FMIBAR) or Flash Slave Memory Information Block Address (FSMIBAR) register. 2. Read the data word by reading out the Flash Memory Information Block Data (FMIBDR) or Flash Slave Memory Information Block Data (FSMIBDR) register.
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8.3.3
Main Block Page Erase
8.3.6
Main Block Write
A flash erase operation sets all of the bits in the erased region. Pages of a main block can be individually erased if their write enable bits are set. This method cannot be used to erase the boot area, if defined. Each page in Main Block 0 and 1 consists of 1024 bytes (512 words). Each page in Main Block 2 consists of 512 bytes (256 words). To erase a page, the following steps are performed: 1. Verify that the Flash Memory Busy (FMBUSY) bit in the FMSTAT or FSMSTAT register is clear. 2. Prevent accesses to the flash memory while erasing is in progress. 3. Set the Page Erase (PER) bit in the FMCTRL or FSMCTRL register. 4. Write to an address within the desired page. 5. Wait until the FMBUSY bit becomes clear again. 6. Check the Erase Error (EERR) bit in the FMSTAT or FSMSTAT register to confirm successful erase of the page. 7. Repeat steps 4 through 6 to erase additional pages. 8. Clear the PER bit. 8.3.4 Main Block Module Erase
Writing is only allowed when global write protection is disabled. Writing by the CPU is only allowed when the write enable bit is set for the sector which contains the word to be written. The CPU cannot write the Boot Area. Only wordwide write access to word-aligned addresses is supported. The following steps are performed to write a word: 1. Verify that the Flash Memory Busy (FMBUSY) bit in the FMSTAT or FSMSTAT register is clear. 2. Prevent accesses to the flash memory while the write is in progress. 3. Set the Program Enable (PE) bit in the FMCTRL or FSMCTRL register. 4. Write a word to the desired word-aligned address. This starts a new pipelined programming sequence. The FMBUSY bit becomes set while the write operation is in progress. The FMFULL bit in the FMSTAT or FSMSTAT register becomes set if a previous write operation is still in progress. 5. Wait until the FMFULL bit becomes clear. 6. Repeat steps 4 and 5 for additional words. 7. Wait until the FMBUSY bit becomes clear again. 8. Check the programming error (PERR) bit in the FMSTAT or FSMSTAT register to confirm successful programming. 9. Clear the Program Enable (PE) bit.
A module erase operation can be used to erase an entire main block. All sections within the block must be enabled for writing. If a boot area is defined in the block, it cannot be erased. The following steps are performed to erase a main 8.3.7 Information Block Write block: 1. Verify that the Flash Memory Busy (FMBUSY) bit in the Writing is only allowed when global write protection is disabled. Writing by the CPU is only allowed when the write enFMSTAT or FSMSTAT register is clear. 2. Prevent accesses to the flash memory while erasing is able bit is set for the sector which contains the word to be written. The CPU cannot write Information Block 0. Only in progress. 3. Set the Module Erase (MER) bit in the FMCTRL or word-wide write access to word-aligned addresses is supported. The following steps are performed to write a word: FSMCTRL register. 4. Write to any address within the desired main block. 5. Wait until the FMBUSY bit becomes clear again. 6. Check the Erase Error (EERR) bit in the FMSTAT or FSMSTAT register to confirm successful erase of the block. 7. Clear the MER bit. 8.3.5 Information Block Module Erase
Erasing an information block also erases the corresponding main block. If a boot area is defined in the main block, neither block can be erased. Page erase is not supported for information blocks. The following steps are performed to erase an information block: 1. Verify that the Flash Memory Busy (FMBUSY) bit in the FMSTAT or FSMSTAT register is clear. 2. Prevent accesses to the flash memory while erasing is in progress. 3. Set the Module Erase (MER) bit in the FMCTRL or FSMCTRL register. 4. Load the FMIBAR or FSMIBAR register with any address within the block, then write any data to the FMIBDR or FSMIBDR register. 5. Wait until the FMBUSY bit becomes clear again. 6. Check the Erase Error (EERR) bit in the FMSTAT or FSMSTAT register to confirm successful erase of the block. 7. Clear the MER bit.
1. Verify that the Flash Memory Busy (FMBUSY) bit in the FMSTAT or FSMSTAT register is clear. 2. Prevent accesses to the flash memory while the write is in progress. 3. Set the Program Enable (PE) bit in the FMCTRL or FSMCTRL register. 4. Write the desired target address into the FMIBAR or FSMIBAR register. 5. Write the data word into the FMIBDR or FSMIBDR register. This starts a new pipelined programming sequence. The FMBUSY bit becomes set while the write operation is in progress. The FMFULL bit in the FMSTAT or FSMSTAT register becomes set if a previous write operation is still in progress. 6. Wait until the FMFULL bit becomes clear. 7. Repeat steps 4 through 6 for additional words. 8. Wait until the FMBUSY bit becomes clear again. 9. Check the programming error (PERR) bit in the FMSTAT or FSMSTAT register to confirm successful programming. 10. Clear the Program Enable (PE) bit.
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8.4
INFORMATION BLOCK WORDS
Two words in the information blocks are dedicated to hold settings that affect the operation of the system: the Function Word in Information Block 0 and the Protection Word in Information Block 1. 8.4.1 Function Word
Table 14 lists all possible boot area encodings. Table 14 Boot Area Encodings BOOT AREA 1111 1110 1101 1100 1011 Size of the Boot Area No Boot Area defined 2K bytes 4K bytes 6K bytes 8K bytes 10K bytes 12K bytes 14K bytes 16K bytes 18K bytes 20K bytes 22K bytes 24K bytes 26K bytes 28K bytes 30K bytes Code Area Start Address 00 0000h 00 0800h 00 1000h 00 1800h 00 2000h 00 2800h 00 3000h 00 3800h 00 4000h 00 4800h 00 5000h 00 5800h 00 6000h 00 6800h 00 7000h 00 7800h
The Function Word resides in the Information Block 0 at address 07Eh. At reset, the Function Word is copied into the FMAR0 register. 15 Reserved 0
8.4.2
Protection Word
1010 1001 1000 0111 0110 0101
The Protection Word resides in Information Block 1 at address 0FEh. At reset, the Protection Word is copied into the FMAR1 register. 15 13 12 10 9 7 6 4 3 1 0
WRPROT RDPROT ISPE
EMPTY
BOOTAREA
BOOTAREA The BOOTAREA field specifies the size of the Boot Area. The Boot Area starts at address 0 and ends at the address specified by this field. The inverted bits of the BOOTAREA field count the number of 2048-byte blocks to be reserved as the Boot Area. The maximum Boot Area size is 30K bytes (address range 0 to 77FFh). The end of the Boot Area defines the start of the Code Area. If the device starts in ISP mode and there is no Boot Area defined EMPTY (encoding 1111b), the device is kept in reset.
0100 0011 0010 0001 0000
ISPE
The EMPTY field indicates whether the flash program memory has been programmed or should be treated as blank. If a majority of the three EMPTY bits are clear, the flash program memory is treated as programmed. If a majority of the EMPTY bits are set, the flash program memory is treated as empty. If the ENV[1:0] inputs (see Section 6.1) are sampled high at reset and the EMPTY bits indicate the flash program memory is empty, the device will begin execution in ISP mode. The device enters ISP mode without regard to the EMPTY status if ENV0 is driven low and ENV1 is driven high. The ISPE field indicates whether the Boot Area is used to hold In-System-Programming routines or user application routines. If a majority of the three ISPE bits are set, the Boot Area is intended to store ISP routines. If majority of the ISPE bits are clear, the Boot Area holds user application routines. Table 15 summarizes all possible EMPTY, ISPE, and Boot Area settings and the corresponding start-up operation for each combination. In DEV mode, the EMPTY bit settings are ignored and the CPU always starts executing from address 0.
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Table 15 CPU Reset Behavior EMPTY ISPE Boot Area Start-Up Operation Device starts in IRE/ ERE mode from Code Area start address Device starts in IRE/ ERE mode from Code Area start address
Table 16 Flash Memory Interface Registers Program Memory FMIBAR FF F940h FMIBDR FF F942h FM0WER FF F944h FM1WER FF F946h FMCTRL FF F94Ch FMSTAT FF F94Eh FMPSR FF F950h FMSTART FF F952h FMTRAN FF F954h FMPROG FF F956h FMPERASE FF F958h FMMERASE0 FF F95Ah FMEND FF F95Eh FMMEND FF F960h FMRCV FF F962h FMAR0 FF F964h FMAR1 FF F966h FMAR2 FF F968h Data Memory FSMIBAR FF F740h FSMIBDR FF F742h FSM0WER FF F744h N/A FSMCTRL FF F74Ch FSMSTAT FF F74Eh FSMPSR FF F750h FSMSTART FF F752h FSMTRAN FF F754h FSMPROG FF F756h FSMPERASE FF F758h FSMMERASE0 FF F75Ah FSMEND FF F75Eh FSMMEND FF F760h FSMRCV FF F762h FSMAR0 FF F764h FSMAR1 FF F766h FSMAR2 FF F768h Description Flash Memory Information Block Address Register Flash Memory Information Block Address Register Flash Memory 0 Write Enable Register Flash Memory 1 Write Enable Register Flash Memory Control Register Flash Memory Status Register Flash Memory Prescaler Register Flash Memory Start Time Reload Register Flash Memory Transition Time Reload Register Flash Memory Programming Time Reload Register Flash Memory Page Erase Time Reload Register Flash Memory Module Erase Time Reload Register 0 Flash Memory End Time Reload Register Flash Memory Module Erase End Time Reload Register Flash Memory Recovery Time Reload Register Flash Memory Auto-Read Register 0 Flash Memory Auto-Read Register 1 Flash Memory Auto-Read Register 2
Not Empty
ISP
Defined
Not Empty
ISP
Not Defined
Not Empty
No ISP
Device starts in IRE/ Don't Care ERE mode from address 0 Defined Not Defined Don't Care Device starts in ISP mode from Code Area start address Device starts in ISP mode and is kept in its reset state
Empty
ISP
Empty Empty RDPROT
ISP No ISP
WRPROT
The RDPROT field controls the global read protection mechanism for the on-chip flash program memory. If a majority of the three RDPROT bits are clear, the flash program memory is protected against read access from the serial debug interface or an external flash programmer. CPU read access is not affected by the RDPROT bits. If a majority of the RDPROT bits are set, read access is allowed. The WRPROT field controls the global write protection mechanism for the on-chip flash program memory. If a majority of the three WRPROT bits are clear, the flash program memory is protected against write access from any source and read access from the serial debug interface. If a majority of the WRPROT bits are set, write access is allowed.
8.5
FLASH MEMORY INTERFACE REGISTERS
There is a separate interface for the program flash and data flash memories. The same set of registers exist in both interfaces. In most cases they are independent of each other, but in some cases the program flash interface controls the interface for both memories, as indicated in the following sections. Table 16 lists the registers.
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8.5.1
Flash Memory Information Block Address Register (FMIBAR/FSMIBAR)
8.5.3
Flash Memory 0 Write Enable Register (FM0WER/FSM0WER)
The FMIBAR register specifies the 8-bit address for read or write access to an information block. Because only word access to the information blocks is supported, the least significant bit (LSB) of the FMIBAR must be 0 (word-aligned). The hardware automatically clears the LSB, without regard to the value written to the bit. The FMIBAR register is cleared after device reset. The CPU bus master has read/write access to this register. 15 Reserved 8 7 IBA 0
The FM0WER register controls section-level write protection for the first half of the flash program memory. The FMS0WER registers controls section-level write protection for the flash data memory. Each data block is divided into 16 8K-byte sections. Each bit in the FM0WER and FSM0WER registers controls write protection for one of these sections. The FM0WER and FSM0WER registers are cleared after device reset, so the flash memory is write protected after reset. The CPU bus master has read/write access to this registers. 15 FM0WE 0
IBA
The Information Block Address field holds the word-aligned address of an information block location accessed during a read or write FM0WEn transaction. The LSB of the IBA field is always clear. Flash Memory Information Block Data Register (FMIBDR/FSMIBDR)
8.5.2
The Flash Memory 0 Write Enable n bits control write protection for a section of a flash memory data block. The address mapping of the register bits is shown below. Bit 0 1-14 15 Logical Address Range 00 0000h-00 1FFFh ... 01 E000h-01 FFFFh
The FMIBDR register holds the 16-bit data for read or write access to an information block. The FMIBDR register is cleared after device reset. The CPU bus master has read/ write access to this register. 15 IBD 0 8.5.4
Flash Memory 1 Write Enable Register (FM1WER)
IBD
The Information Block Data field holds the data word for access to an information block. For write operations the IBD field holds the data word to be programmed into the information block location specified by the IBA address. During a read operation from an information block, the IBD field receives the data word read from the location specified by the IBA address.
The FM1WER register controls write protection for the second half of the program flash memory. The data block is divided into 16 8K-byte sections. Each bit in the FM1WER register controls write protection for one of these sections. The FM1WER register is cleared after device reset, so the flash memory is write protected after reset. The CPU bus master has read/write access to this registers. 15 FM1WE 0
FM1WEn
The Flash Memory 1 Write Enable n bits control write protection for a section of a flash memory data block. The address mapping of the register bits is shown below. Bit 0 1-14 15 Logical Address Range 02 0000h-02 1FFFh ... 03 E000h-03 FFFFh
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8.5.5
Flash Data Memory 0 Write Enable Register (FSM0WER)
DISVRF
The FSM0WER register controls write protection for the flash data memory. The data block is divided into 16 512byte sections. Each bit in the FSM0WER register controls write protection for one of these sections. The FSM0WER register is cleared after device reset, so the flash memory is write protected after reset. The CPU bus master has read/ write access to this registers. 15 FSM0WE 0
IENPROG
FSM0WEn
The Flash Data Memory 0 Write Enable n bits control write protection for a section of a flash PE memory data block. The address mapping of the register bits is shown below. Bit 0 1-14 15 Logical Address Range 0E 0000h-0E 01FFh ... 0E 1E00h-0E 1FFFh PER
8.5.6
Flash Memory Control Register (FMCTRL/ FSMCTRL)
This register controls the basic functions of the Flash program memory. The register is clear after device reset. The CPU bus master has read/write access to this register. 7 6 5 4 3 2 1 0
MER PER PE IENPROG DISVRF Res. CWD LOWPRW
LOWPRW
CWD
The Low Power Mode controls whether flash program memory is operated in low-power mode, which draws less current when data is read. This is accomplished be only accessing MER the flash program memory during the first half of the clock period. The low-power mode must not be used at System Clock frequencies above 25 MHz, otherwise a read access may return undefined data. This bit must not be changed while the flash program memory is busy being programmed or erased. 0 - Normal mode. 1 - Low-power mode. The CPU Write Disable bit controls whether the CPU has write access to flash memory. This bit must not be changed while FMBUSY is set. 0 - The CPU has write access to the flash memory 1 - An external debugging tool is the current "owner" of the flash memory interface, so write accesses by the CPU are inhibited.
The Disable Verify bit controls the automatic verification feature. This bit must not be changed while the flash program memory is busy being programmed or erased. 0 - New flash program memory contents are automatically verified after programming. 1 - Automatic verification is disabled. The Interrupt Enable for Program bit is clear after reset. The flash program and data memories share a single interrupt channel but have independent interrupt enable control bits. 0 - No interrupt request is asserted to the ICU when the FMFULL bit is cleared. 1 - An interrupt request is made when the FMFULL bit is cleared and new data can be written into the write buffer. The Program Enable bit controls write access of the CPU to the flash program memory. This bit must not be altered while the flash program memory is busy being programmed or erased. The PER and MER bits must be clear when this bit is set. 0 - Programming the flash program memory by the CPU is disabled. 1 - Programming the flash program memory is enabled. The Page Erase Enable bit controls whether a a valid write operation triggers an erase operation on a 1024-byte page of flash memory. Page erase operations are only supported for the main blocks, not the information blocks. A page erase operation on an information block is ignored and does not alter the information block. When the PER bit is set, the PE and MER bits must be clear. This bit must not be changed while the flash program memory is busy being programmed or erased. 0 - Page erase mode disabled. Write operations are performed normally. 1 - A valid write operation to a word location in program memory erases the page that contains the word. The Module Erase Enable bit controls whether a valid write operation triggers an erase operation on an entire block of flash memory. If an information block is written in this mode, both the information block and its corresponding main block are erased. When the MER bit is set, the PE and PER bits must be clear. This bit must not be changed while the flash program memory is busy being programmed or erased. 0 - Module erase mode disabled. Write operations are performed normally. 1 - A valid write operation to a word location in a main block erases the block that contains the word. A valid write operation to a word location in an information block erases the block that contains the word and its associated main block.
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8.5.7
Flash Memory Status Register (FMSTAT/ FSMSTAT)
DERR
This register reports the currents status of the on-chip Flash memory. The FLSR register is clear after device reset. The CPU bus master has read/write access to this register. 7 5 4 3 2 1 0
Reserved
DERR FMFULL FMBUSY PERR EERR 8.5.8
The Data Loss Error bit indicates that a buffer overrun has occurred during a programming sequence. After a data loss error occurs, software can clear the DERR bit by writing a 1 to it. Writing a 0 to the DERR bit has no effect. Software must not change this bit while the flash program memory is busy being programmed or erased. 0 - No data loss error occurred. 1 - Data loss error occurred. Flash Memory Prescaler Register (FMPSR/ FSMPSR)
EERR
PERR
FMBUSY
FMFULL
The Erase Error bit indicates whether an error has occurred during a page erase or module (block) erase. After an erase error occurs, software can clear the EERR bit by writing a 1 to it. Writing a 0 to the EERR bit has no effect. Software must not change this bit while the flash program memory is busy being programmed or erased. 0 - The erase operation was successful. 1 - An erase error occurred. The Program Error bit indicates whether an error has occurred during programming. After a programming error occurs, software can clear the PERR bit by writing a 1 to it. Writing a 0 to the PERR bit has no effect. Software must not change this bit while the flash program memory is busy being programmed or erased. 0 - The programming operation was successful. 1 - A programming error occurred. The Flash Memory Busy bit indicates whether the flash memory (either main block or information block) is busy being programmed or erased. During that time, software must not request any further flash memory operations. If such an attempt is made, the CPU is stopped as long as the FMBUSY bit is active. The CPU must not attempt to read from program memory (including instruction fetches) while it is busy. 0 - Flash memory is ready to receive a new erase or programming request. 1 - Flash memory busy with previous erase or programming operation. The Flash Memory Buffer Full bit indicates whether the write buffer for programming is full or not. When the buffer is full, new erase and write requests may not be made. The IENPROG bit can be enabled to trigger an interrupt when the buffer is ready to receive a new request. 0 - Buffer is ready to receive new erase or write requests. 1 - Buffer is full. No new erase or write requests can be accepted.
The FMPSR register is a byte-wide read/write register that selects the prescaler divider ratio. The CPU must not modify this register while an erase or programming operation is in progress (FMBUSY is set). At reset, this register is initialized to 04h if the flash memory is idle. The CPU bus master has read/write access to this register. 7 Reserved 5 4 FTDIV 0
FTDIV 8.5.9
The prescaler divisor scales the frequency of the System Clock by a factor of (FTDIV + 1). Flash Memory Start Time Reload Register (FMSTART/FSMSTART)
The FMSTART/FSMSTART register is a byte-wide read/ write register that controls the program/erase start delay time. Software must not modify this register while a program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to 18h if the flash memory is idle. The CPU bus master has read/write access to this register. 7 FTSTART 0
FTSTART
The Flash Timing Start Delay Count field generates a delay of (FTSTART + 1) prescaler output clocks.
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8.5.10
Flash Memory Transition Time Reload Register (FMTRAN/FSMTRAN)
8.5.13
Flash Memory Module Erase Time Reload Register 0 (FMMERASE0/FSMMERASE0)
The FMTRAN/FMSTRAN register is a byte-wide read/write register that controls some program/erase transition times. Software must not modify this register while program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to 30h if the flash memory is idle. The CPU bus master has read/write access to this register. 7 FTTRAN 0
The FMMERASE0/FSMMERASE0 register is a byte-wide read/write register that controls the module erase pulse width. Software must not modify this register while a program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to EAh if the flash memory is idle. The CPU bus master has read/write access to this register. 7 FTMER 0
FTTRAN
The Flash TIming Transition Count field specifies a delay of (FTTRAN + 1) prescaler output clocks. Flash Memory Programming Time Reload Register (FMPROG/FSMPROG)
FTMER
8.5.11
The Flash Timing Module Erase Pulse Width field specifies a module erase pulse width of 4096 x (FTMER + 1) prescaler output clocks. Flash Memory End Time Reload Register (FMEND/FSMEND)
8.5.14
The FMPROG/FSMPROG register is a byte-wide read/write register that controls the programming pulse width. Software must not modify this register while a program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to 16h if the flash memory is idle. The CPU bus master has read/write access to this register. 7 FTPROG 0
The FMEND/FSMEND register is a byte-wide read/write register that controls the delay time after a program/erase operation. Software must not modify this register while a program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to 18h when the flash memory on the chip is idle. The CPU bus master has read/write access to this register. 7 FTEND 0
FTPROG
The Flash Timing Programming Pulse Width field specifies a programming pulse width of 8 x (FTPROG + 1) prescaler output clocks.
FTEND
8.5.12
Flash Memory Page Erase Time Reload Register (FMPERASE/FSMPERASE) 8.5.15
The Flash Timing End Delay Count field specifies a delay of (FTEND + 1) prescaler output clocks. Flash Memory Module Erase End Time Reload Register (FMMEND/FSMMEND)
The FMPERASE/FSMPERASE register is a byte-wide read/write register that controls the page erase pulse width. Software must not modify this register while a program/ erase operation is in progress (FMBUSY set). At reset, this register is initialized to 04h if the flash memory is idle. The CPU bus master has read/write access to this register. 7 FTPER 0
The FMMEND/FSMMEND register is a byte-wide read/write register that controls the delay time after a module erase operation. Software must not modify this register while a program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to 3Ch if the flash memory is idle. The CPU bus master has read/write access to this register. 7 0 FTMEND
FTPER
The Flash Timing Page Erase Pulse Width field specifies a page erase pulse width of 4096 x (FTPER + 1) prescaler output clocks. FTMEND
The Flash Timing Module Erase End Delay Count field specifies a delay of 8 x (FTMEND + 1) prescaler output clocks.
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8.5.16
Flash Memory Recovery Time Reload Register (FMRCV/FSMRCV)
8.5.18
Flash Memory Auto-Read Register 1 (FMAR1/ FSMAR1)
The FMRCV/FSMRCV register is a byte-wide read/write register that controls the recovery delay time between two flash memory accesses. Software must not modify this register while a program/erase operation is in progress (FMBUSY set). At reset, this register is initialized to 04h if the flash memory is idle. The CPU bus master has read/write access to this register. 7 FTRCV 0
The FMAR1 register contains a copy of the Protection Word from Information Block 1. The Protection Word is sampled at reset. The contents of the FMAR1 register define the current Flash memory protection settings. The CPU bus master has read-only access to this register. The FSMAR1 register has the same value as the FMAR1 register. The format is the same as the format of the Protection Word (see Section 8.4.2). 15 13 12 10 9 7 6 4 3 1 0
WRPROT RDPROT ISPE EMPTY BOOTAREA 1 FTRCV The Flash Timing Recovery Delay Count field specifies a delay of (FTRCV + 1) prescaler output clocks. Flash Memory Auto-Read Register 0 (FMAR0/ FSMAR0)
8.5.19
Flash Memory Auto-Read Register 2 (FMAR2/ FSMAR2)
8.5.17
The FMAR0/FSMAR0 register contains a copy of the Function Word from Information Block 0. The Function Word is sampled at reset. The CPU bus master has read-only access to this register. The FSMAR0 register has the same The FSMAR2 register has the same value as the FMAR2 register. value as the FMAR0 register 15 Reserved 0 7 CADR7:0 0
The FMAR2 register is a word-wide read-only register, which is loaded during reset. It is used to build the Code Area start address. At reset, the CPU executes a branch, using the contents of the FMAR2 register as displacement. The CPU bus master has read-only access to this register.
15 CADR15
14 CADR14:11
11
10 CADR10:8
8
The Code Area Start Address (bits 10:0) contains the lower 11 bits of the Code Area start address. The CADR10:0 field has a fixed value of 0. CADR14:11 The Code Area Start Address (bits 14:11) are loaded during reset with the inverted value of BOOTAREA3:0. CADR15 The Code Area Start Address (bits 15) contains the upper bit of the Code Area start address. The CADR15 field has a fixed value of 0.
CADR10:0
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9.0
DMA Controller
Table 17 DMA Channel Assignment Channel 0 (Primary) 0 (Secondary) 1 (Primary) 1 (Secondary) 2 (Primary) 2 (Secondary) 3 (Primary) 3 (Secondary) Peripheral Reserved USART USART Reserved Audio Interface CVSD/PCM Transcoder Audio Interface CVSD/PCM Transcoder Transaction N/A R W N/A R R W W Register N/A RXBUF TXBUF N/A ARDR0 PCMOUT ATDR0 PCMIN
The DMA Controller (DMAC) has a register-based programming interface, as opposed to an interface based on I/O control blocks. After loading the registers with source and destination addresses, as well as block size and type of operation, a DMAC channel is ready to respond to DMA transfer requests. A request can only come from on-chip peripherals or software, not external peripherals. On receiving a DMA transfer request, if the channel is enabled, the DMAC performs the following operations: 1. Arbitrates to become master of the CPU bus. 2. Determines priority among the DMAC channels, one clock cycle before T1 of the DMAC transfer cycle. (T1 is the first clock cycle of the bus cycle.) Priority among the DMAC channels is fixed in descending order, with Channel 0 having the highest priority. 3. Executes data transfer bus cycle(s) selected by the values held in the control registers of the channel being serviced, and according to the accessed memory address. The DMAC acknowledges the request during the bus cycle that accesses the requesting device. 4. If the transfer of a block is terminated, the DMAC does the following: Updates the termination bits. Generates an interrupt (if enabled). Goes to step 6. 5. If DMRQn is still active, and the Bus Policy is "continuous", returns to step 3. 6. Returns mastership of the CPU bus to the CPU. Each DMAC channel can be programmed for direct (flyby) or indirect (memory-to-memory) data transfers. Once a DMAC transfer cycle is in progress, the next transfer request is sampled when the DMAC acknowledge is de-asserted, then on the rising edge of every clock cycle. The configuration of either address freeze or address update (increment or decrement) is independent of the number of transferred bytes, transfer direction, or number of bytes in each DMAC transfer cycle. All these can be configured for each channel by programming the appropriate control registers. Each DMAC channel has eight control registers. DMAC channels are described hereafter with the suffix n, where n = 0 to 3, representing the channel number in the registernames.
9.2
TRANSFER TYPES
The DMAC uses two data transfer modes, Direct (Flyby) and Indirect (Memory-to-Memory). The choice of mode depends on the required bus performance and whether direct mode is available for the transfer. Indirect mode must be used when the source and destination have differing bus widths, when both the source and destination are in memory, and when the destination does not support direct mode. 9.2.1 Direct (Flyby) Transfers
In direct mode each data item is transferred using a single bus cycle, without reading the data into the DMAC. It provides the fastest transfer rate, but it requires identical source and destination bus widths. The DMAC cannot use Direct cycles between two memory devices. One of the devices must be an I/O device that supports the Direct (Flyby) mechanism, as shown in Figure 3.
Bus State T1 CLK T2 Tidle T1
DMRQ[3:0]
9.1
CHANNEL ASSIGNMENT
ADDR
ADCA
Table 17 shows the assignment of the DMA channels to different tasks. Four channels can be shared by a primary and an secondary function. However, only one source at a time can be enabled. If a channel is used for memory block transfers, other resources must be disabled.
DMACK[3:0]
DS005
Figure 3. Direct DMA Cycle Followed by a CPU Cycle
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Direct mode supports two bus policies: intermittent and continuous. In intermittent mode, the DMAC gives bus mastership back to the CPU after every cycle. In continuous mode, the DMAC remains bus master until the transfer is completed. The maximum bus throughput in intermittent mode is one transfer for every three System Clock cycles. The maximum bus throughput in continuous mode is one transfer for every clock cycle. The I/O device which made the DMA request is called the implied I/O device. The other device can be either memory or another I/O device, and is called the addressed device. Because only one address is required in direct mode, this address is taken from the corresponding ADCAn counter. The DMAC channel generates either a read or a write bus cycle, as controlled by the DMACNTLn.DIR bit. When the DMACNTLn.DIR bit is clear, a read bus cycle from the addressed device is performed, and the data is written to the implied I/O device. When the DMACNTLn.DIR bit is set, a write bus cycle to the addressed device is performed, and the data is read from the implied I/O device. The configuration of either address freeze or address update (increment or decrement) is independent of the number of transferred bytes, transfer direction, or number of bytes in each DMAC transfer cycle. All these can be configured for each channel by programming the appropriate control register. Whether 8 or 16 bits are transferred in each cycle is selected by the DMACNTLn.TCS register bit. After the data item has been transferred, the BLTCn counter is decremented by one. The ADCAn counter is updated according to the INCA and ADA fields in the DMACNTLn register. 9.2.2 Indirect (Memory-To-Memory) Transfers
9.3
OPERATION MODES
The DMAC operates in three different block transfer modes: single transfer, double buffer, and auto-initialize. 9.3.1 Single Transfer Operation
This mode provides the simplest way to accomplish a single block data transfer. Initialization 1. Write the block transfer addresses and byte count into the corresponding ADCAn, ADCBn, and BLTCn counters. 2. Clear the DMACNTLn.OT bit to select non-auto-initialize mode. Clear the DMASTAT.VLD bit by writing a 1 to it. 3. Set the DMACNTLn.CHEN bit to activate the channel and enable it to respond to DMA transfer requests. Termination When the BLTCn counter reaches 0: 1. The transfer operation terminates. 2. The DMASTAT.TC and DMASTAT.OVR bits are set, and the DMASTAT.CHAC bit is cleared. 3. An interrupt is generated if enabled by the DMACNTLn.ETC or DMACNTLn.EOVR bits. The DMACNTLn.CHEN bit must be cleared before loading the DMACNTLn register to avoid prematurely starting a new DMA transfer. 9.3.2 Double Buffer Operation
This mode allows software to set up the next block transfer while the current block transfer proceeds. Initialization 1. Write the block transfer addresses and byte count into the ADCAn, ADCBn, and BLTCn counters. 2. Clear the DMACNTLn.OT bit to select non-auto-initialize mode. Clear the DMASTAT.VLD bit by writing a 1 to it. 3. Set the DMACNTLn.CHEN bit. This activates the channel and enables it to respond to DMA transfer requests. 4. While the current block transfer proceeds, write the addresses and byte count for the next block into the ADRAn, ADRBn, and BLTRn registers. The BLTRn register must be written last, because it sets the DMASTAT.VLD bit which indicates that all the parameters for the next transfer have been updated.
In indirect (memory-to-memory) mode, data transfers use two consecutive bus cycles. The data is first read into a temporary register, and then written to the destination in the following cycle. This mode is slower than the direct (flyby) mode, but it provides support for different source and destination bus widths. Indirect mode must be used for transfers between memory devices. If an intermittent bus policy is used, the maximum throughput is one transfer for every five clock cycles. If a continuous bus policy is used, maximum throughput is one transfer for every two clock cycles.
When the DMACNTLn.DIR bit is 0, the first bus cycle reads data from the source using the ADCAn counter, while the Continuation/Termination second bus cycle writes the data into the destination using When the BLTCn counter reaches 0: the ADCBn counter. When the DMACNTLn.DIR bit is set, the first bus cycle reads data from the source using the AD- 1. The DMASTAT.TC bit is set. CBn counter, while the second bus cycle writes the data into 2. An interrupt is generated if enabled by the DMACNTLn.ETC bit. the destination addressed by the ADCAn counter. 3. The DMAC channel checks the value of the VLD bit. The number of bytes transferred in each cycle is taken from the DMACNTLn.TCS register bit. After the data item has If the DMASTAT.VLD bit is set: been transferred, the BLTCn counter is decremented by 1. The channel copies the ADRAn, ADRBn, and BLTRn one. The ADCAn and ADCBn counters are updated accordvalues into the ADCAn, ADCBn, and BLTCn registers. ing to the INCA, INCB, ADA, and ADB fields in the 2. The DMASTAT.VLD bit is cleared. DMACNTLn register. 3. The next block transfer is started.
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If the DMASTAT.VLD bit is clear: 1. 2. 3. 4. The transfer operation terminates. The channel sets the DMASTAT.OVR bit. The DMASTAT.CHAC bit is cleared. An interrupt is generated if enabled DMACNTLn.EOVR bit.
by
the
The DMACNTLn.CHEN bit must be cleared before loading the DMACNTLn register to avoid prematurely starting a new DMA transfer.
Note: The ADCBn and ADRBn registers are used only in indirect (memory-to-memory) transfer. In direct (flyby) 9.5 DEBUG MODE mode, the DMAC does not use them and therefore does not When the FREEZE signal is active, all DMA operations are copy ADRBn into ADCBn. stopped. They will start again when the FREEZE signal 9.3.3 Auto-Initialize Operation goes inactive. This allows breakpoints to be used in debug This mode allows the DMAC to continuously fill the same systems. memory area without software intervention.
For each channel, use the software DMA transfer request only when the corresponding hardware DMA request is inactive and no terminal count interrupt is pending. Software can poll the DMASTAT.CHAC bit to determine whether the DMA channel is already active. After verifying the DMASTATn.CHAC bit is clear (channel inactive), check the DMASTATn.TC (terminal count) bit. If the TC bit is clear, then no terminal count condition exists and therefore no terminal count interrupt is pending. If the channel is not active and no terminal count interrupt is pending, software may request a DMA transfer.
9.6
DMA CONTROLLER REGISTER SET
Initialization There are four identical sets of DMA controller registers, as 1. Write the block addresses and byte count into the ADlisted in Table 18. CAn, ADCBn, and BLTCn counters, as well as the Table 18 DMA Controller Registers ADRAn, ADRBn, and BLTRn registers. 2. Set the DMACNTLn.OT bit to select auto-initialize Name Address Description mode. 3. Set the DMACNTLn.CHEN bit to activate the channel Device A Address and enable it to respond to DMA transfer requests. ADCA0 FF F800h Counter Register Continuation Device A Address ADRA0 FF F804h When the BLTCn counter reaches 0: Register 1. The contents of the ADRAn, ADRBn, and BLTRn regisDevice B Address ters are copied to the ADCAn, ADCBn, and BLTCn ADCB0 FF F808h Counter Register counters. 2. The DMAC channel checks the value of the DMASDevice B Address ADRB0 FF F80Ch TAT.TC bit. Register If the DMASTAT.TC bit is set: Block Length BLTC0 FF F810h 1. The DMASTAT.OVR bit is set. Counter Register 2. A level interrupt is generated if enabled by the BLTR0 FF F814h Block Length Register DMACNTLn.EOVR bit. 3. The operation is repeated. DMACNTL0 FF F81Ch DMA Control Register If the DMASTAT.TC bit is clear: DMASTAT0 FF F81Eh DMA Status Register 1. The DMASTAT.TC bit is set. 2. A level interrupt is generated if enabled by the Device A Address ADCA1 FF F820h DMACNTLn.ETC bit. Counter Register 3. The DMAC operation is repeated. Device A Address ADRA1 FF F824h Termination Register The DMA transfer is terminated when the Device B Address ADCB1 FF F828h DMACNTLn.CHEN bit is cleared. Counter Register
9.4
SOFTWARE DMA REQUEST
ADRB1 BLTC1 BLTR1 DMACNTL1 DMASTAT1 FF F82Ch FF F830h FF F834h FF F83Ch FF F83Eh
In addition to the hardware requests from I/O devices, a DMA transfer request can also be initiated by software. A software DMA transfer request must be used for block copying between memory devices. When the DMACNTLn.SWRQ bit is set, the corresponding DMA channel receives a DMA transfer request. When the DMACNTLn.SWRQ bit is clear, the software DMA transfer request of the corresponding channel is inactive.
Device B Address Register Block Length Counter Register Block Length Register DMA Control Register DMA Status Register
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Table 18 DMA Controller Registers Name ADCA2 ADRA2 ADCB2 ADRB2 BLTC2 BLTR2 DMACNTL2 DMASTAT2 ADCA3 ADRA3 ADCB3 ADRB3 BLTC3 BLTR3 DMACNTL3 DMASTAT3 9.6.1 Address FF F840h FF F844h FF F848h FF F84Ch FF F850h FF F854h FF F85Ch FF F85Eh FF F860h FF F864h FF F868h FF F86Ch FF F870h FF F874h FF F87Ch FF F87Eh Description Device A Address Counter Register Device A Address Register Device B Address Counter Register Device B Address Register Block Length Counter Register Block Length Register DMA Control Register DMA Status Register Device A Address Counter Register Device A Address Register Device B Address Counter Register Device B Address Register Block Length Counter Register Block Length Register DMA Control Register DMA Status Register
9.6.2
Device A Address Register (ADRAn)
The Device A Address register is a 32-bit, read/write register. It holds the 24-bit starting address of either the next source data block, or the next destination data area, according to the DIR bit in the DMACNTLn register. The upper 8 bits of the ADRAn register are reserved and always clear. 31 24 23 Device A Address 0
Reserved
9.6.3
Device B Address Counter Register (ADCBn)
The Device B Address Counter register is a 32-bit, read/ write register. It holds the current 24-bit address of either the source data item, or the destination location, according to the DIR bit in the CNTLn register. The ADCBn register is updated after each transfer cycle by INCB field of the DMACNTLn register according to ADB bit of the DMACNTLn register. In direct (flyby) mode, this register is not used. The upper 8 bits of the ADCBn register are reserved and always clear. 31 24 23 Device B Address Counter 0
Reserved
9.6.4
Device B Address Register (ADRBn)
The Device B Address register is a 32-bit, read/write register. It holds the 24-bit starting address of either the next source data block or the next destination data area, according to the DIR bit in the CNTLn register. In direct (flyby) mode, this register is not used. The upper 8 bits of the ADCRBn register are reserved and always clear. 31 24 23 Device B Address 0
Reserved
Device A Address Counter Register (ADCAn) 9.6.5 Block Length Counter Register (BLTCn) The Block Length Counter register is a 16-bit, read/write register. It holds the current number of DMA transfers to be executed in the current block. BLTCn is decremented by one after each transfer cycle. A DMA transfer may consist of 1 or 2 bytes, as selected by the DMACNTLn.TCS bit. 15 Block Length Counter Note: 0000h is interpreted as 216-1 transfer cycles. 0
The Device A Address Counter register is a 32-bit, read/ write register. It holds the current 24-bit address of either the source data item or the destination location, depending on the state of the DIR bit in the CNTLn register. The ADA bit of DMACNTLn register controls whether to adjust the pointer in the ADCAn register by the step size specified in the INCA field of DMACNTLn register. The upper 8 bits of the ADCAn register are reserved and always clear. 31 24 23 Device A Address Counter 0
Reserved
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9.6.6
Block Length Register (BLTRn)
DIR
The Block Length register is a 16-bit, read/write register. It holds the number of DMA transfers to be performed for the next block. Writing this register automatically sets the DMASTAT.VLD bit. 15 Block Length Note: 0000h is interpreted as 216-1 transfer cycles. 9.6.7 DMA Control Register (DMACNTLn) BPC 0 OT
The DMA Control register n is a word-wide, read/write register that controls the operation of DMA channel n. This register is cleared at reset. Reserved bits must be written with 0. 7 BPC 6 OT 5 DIR 4 IND 3 2 1 0
TCS EOVR ETC CHEN
15 Res.
14
13
12 ADB
11
10
9
8 SWRQ
INCB
INCA
ADA SWRQ
CHEN
ETC
EOVR
TCS
IND
The Channel Enable bit must be set to enable any DMA operation on this channel. Writing a 1 to this bit starts a new DMA transfer even if it is currently a 1. If all DMACNTLn.CHEN bits are clear, the DMA clock is disabled to reduce power. 0 - Channel disabled. 1 - Channel enabled. If the Enable Interrupt on Terminal Count bit is set, it enables an interrupt when the DMASTAT.TC bit is set. 0 - Interrupt disabled. 1 - Interrupt enabled. If the Enable Interrupt on OVR bit is set, it enables an interrupt when the DMASTAT.OVR bit is set. 0 - Interrupt disabled. 1 - Interrupt enabled. The Transfer Cycle Size bit specifies the number of bytes transferred in each DMA transfer cycle. In direct (fly-by) mode, undefined results occur if the TCS bit is not equal to the addressed memory bus width. 0 - Byte transfers (8 bits per cycle). 1 - Word transfers (16 bits per cycle). The Direct/Indirect Transfer bit specifies the transfer type. 0 - Direct transfer (flyby). 1 - Indirect transfer (memory-to-memory).
ADA
INCA
ADB
INCB
The Transfer Direction bit specifies the direction of the transfer relative to Device A. 0 - Device A (pointed to by the ADCAn register) is the source. In Fly-By mode a read transaction is initialized. 1 - Device A (pointed to by the ADCAn register) is the destination. In Fly-By mode a write transaction is initialized. The Operation Type bit specifies the operation mode of the DMA controller. 0 - Single-buffer mode or double-buffer mode enabled. 1 - Auto-Initialize mode enabled. The Bus Policy Control bit specifies the bus policy applied by the DMA controller. The operation mode can be either intermittent (cycle stealing) or continuous (burst). 0 - Intermittent operation. The DMAC channel relinquishes the bus after each transaction, even if the request is still asserted. 1 - Continuous operation. The DMAC channel n uses the bus continuously as long as the request is asserted. This mode can only be used for software DMA requests. For hardware DMA requests, the BPC bit must be clear. The Software DMA Request bit is written with a 1 to initiate a software DMA request. Writing a 0 to this bit deactivates the software DMA request. The SWRQ bit must only be written when the DMRQ signal for this channel is inactive (DMASTAT.CHAC = 0). 0 - Software DMA request is inactive. 1 - Software DMA request is active. If the Device A Address Control bit is set, it enables updating the Device A address. 0 - ADCAn address unchanged. 1 - ADCAn address incremented or decremented, according to INCA field of DMACNTLn register. The Increment/Decrement ADCAn field specifies the step size for the Device A address increment/decrement. 00 - Increment ADCAn register by 1. 01 - Increment ADCAn register by 2. 10 - Decrement ADCAn register by 1. 11 - Decrement ADCAn register by 2. If the Device B Address Control bit is set, it enables updating the Device B Address. 0 - ADCBn address unchanged. 1 - ADCBn address incremented or decremented, according to INCB field of DMACNTLn register. The Increment/Decrement ADCBn field specifies the step size for the Device B address increment/decrement. 00 - Increment ADCBn register by 1. 01 - Increment ADCBn register by 2. 10 - Decrement ADCBn register by 1. 11 - Decrement ADCBn register by 2.
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9.6.8
DMA Status Register (DMASTAT)
The DMA status register is a byte-wide, read register that holds the status information for the DMA channel n. This register is cleared at reset. The reserved bits always return zero when read. The VLD, OVR and TC bits are sticky (once set by the occurrence of the specific condition, they remain set until explicitly cleared by software). These bits can be individually cleared by writing 1 to the bit positions in the DMASTAT register to be cleared. Writing 0 to these bits has no effect 7 Reserved 4 3 2 1 0 TC
VLD CHAC OVR
TC
OVR
CHAC
VLD
The Terminal Count bit indicates whether the transfer was completed by a terminal count condition (BLTCn Register reached 0). 0 - Terminal count condition did not occur. 1 - Terminal count condition occurred. The behavior of the Channel Overrun bit depends on the operation mode (single buffer, double buffer, or auto-initialize) of the DMA channel. In double-buffered mode (DMACNTLn.OT = 0): The OVR bit is set when the present transfer is completed (BLTCn = 0), but the parameters for the next transfer (address and block length) are not valid (DMASTAT.VLD = 0). In auto-initialize mode (DMACNTLn.OT = 1): The OVR bit is set when the present transfer is completed (BLTCn = 0), and the DMASTAT.TC bit is still set. In single-buffer mode: Operates in the same way as double-buffer mode. In single-buffered mode, the DMASTAT.VLD bit should always be clear, so it will also be set when the DMASTAT.TC bit is set. Therefore, the OVR bit can be ignored in this mode. The Channel Active bit continuously indicates the active or inactive status of the channel, and therefore, it is read only. Data written to the CHAC bit is ignored. 0 - Channel inactive. 1 - Indicates that the channel is active (CHEN bit in the CNTLn register is 1 and BLTCn > 0) The Transfer Parameters Valid bit specifies whether the transfer parameters for the next block to be transferred are valid. Writing the BLTRn register automatically sets this bit. The bit is cleared in the following cases: The present transfer is completed and the ADRAn, ADRBn (indirect mode only), and BLTR registers are copied to the ADCAn, ADCBn (indirect mode only), and BLTCn registers. Writing 1 to the VLD bit.
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10.0 Interrupts
Interrupt vector numbers are always positive, in the range 10h to 3Fh. The IVCT register contains the interrupt vector of the enabled and pending interrupt with the highest priority. The interrupt vector 10h corresponds to IRQ0 and the lowest priority, while the vector 3Fh corresponds to IRQ47 and the highest priority. The CPU performs an interrupt acThe priorities of the maskable interrupts are hardwired and knowledge bus cycle on receiving a maskable interrupt retherefore fixed. The implemented interrupts are named quest from the ICU. During the interrupt acknowledge cycle, IRQ0 through IRQ47, in which IRQ0 has the lowest priority a byte is read from address FF FE00h (IVCT register). The and IRQ47 has the highest priority. (IRQ0 is not implement- byte is used as an index into the Dispatch Table to detered, so IRQ1 is the lowest priority interrupt that normally may mine the address of the interrupt handler. occur.) Because IRQ0 is not connected to any interrupt source, it The Interrupt Control Unit (ICU) receives interrupt requests from internal and external sources and generates interrupts to the CPU. Interrupts from the timers, UARTs, Microwire/ SPI interface, and Multi-Input Wake-Up module are all maskable interrupts. The highest-priority interrupt is the Non-Maskable Interrupt (NMI), which is triggered by a falling edge received on the NMI input pin. 10.2.1 Maskable Interrupt Processing
10.1
NON-MASKABLE INTERRUPTS
The Interrupt Control Unit (ICU) receives the external NMI input and generates the NMI signal driven to the CPU. The NMI input is an asynchronous input with Schmitt trigger characteristics and an internal synchronization circuit, therefore no external synchronizing circuit is needed. The NMI pin triggers an exception on its falling edge. 10.1.1 Non-Maskable Interrupt Processing
would seem that the interrupt vector would never return the value 10h. If it does return a value of 10h, the entry in the dispatch table should point to a default interrupt handler that handles this error condition. One possible condition for this to occur is deassertion of the interrupt before the interrupt acknowledge cycle.
10.3
INTERRUPT CONTROLLER REGISTERS
Table 19 Interrupt Controller Registers Name IVCT Address FF FE00h Description Interrupt Vector Register Non-Maskable Interrupt Status Register External NMI Trap Control and Status Register Interrupt Status Register 0 Interrupt Status Register 1 Interrupt Status Register 2 Interrupt Enable and Mask Register 0 Interrupt Enable and Mask Register 1 Interrupt Enable and Mask Register 2
Table 19 lists the ICU registers.
The CPU performs an interrupt acknowledge bus cycle when beginning to process a non-maskable interrupt. At reset, NMI interrupts are disabled and must remain disabled until software initializes the interrupt table, interrupt base register (INTBASE), and the interrupt mode. The external NMI interrupt is enabled by setting the EXNMI.ENLCK bit and will remain enabled until a reset occurs. Alternatively, the external NMI interrupt can be enabled by setting the EXNMI.EN bit and will remain enabled until an interrupt event or a reset occurs.
NMISTAT
FF FE02h
10.2
MASKABLE INTERRUPTS
EXNMI
FF FE04h
The ICU receives level-triggered interrupt request signals from 47 sources and generates a vectored interrupt to the CPU when required. Priority among the implemented interrupt sources (named IRQ1 through IRQ47) is fixed. The maskable interrupts are globally enabled and disabled by the E bit in the PSR register. The EI and DI instructions are used to set (enable) and clear (disable) this bit. The global maskable interrupt enable bit (I bit in the PSR) must also be set before any maskable interrupts are taken. Each interrupt source can be individually enabled or disabled under software control through the ICU interrupt enable registers and also through interrupt enable bits in the peripherals that request the interrupts. The ICU supports IRQ0, but in the CP3CN23 it is not connected to any interrupt source.
ISTAT0 ISTAT1 ISTAT2 IENAM0 IENAM1 IENAM2
FF FE0Ah FF FE0Ch FF FE20h FF FE0Eh FF FE10h FF FE22h
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10.3.1
Interrupt Vector Register (IVCT)
10.3.3
The IVCT register is a byte-wide read-only register which reports the encoded value of the highest priority maskable interrupt that is both asserted and enabled. The valid range is from 10h to 3Fh. The register is read by the CPU during an interrupt acknowledge bus cycle, and INTVECT is valid during that time. It may contain invalid data while INTVECT is updated. 7 0 6 0 5 INTVECT 0
External NMI Trap Control and Status Register (EXNMI)
The EXNMI register is a byte-wide read/write register. It indicates the current value of the NMI pin and controls the NMI interrupt trap generation based on a falling edge of the NMI pin. TST, EN and ENLCK are cleared on reset. When writing to this register, all reserved bits must be written with 0 for the device to function properly 7 Reserved 3 2 ENLCK 1 PIN 0 EN
INTVECT
The Interrupt Vector field indicates the highest priority interrupt which is both asserted and enabled.
EN
10.3.2
Non-Maskable Interrupt Status Register (NMISTAT)
The NMISTAT register is a byte-wide read-only register. It holds the status of the current pending Non-Maskable Interrupt (NMI) requests. On the CP3CN23, the external NMI input is the only source of NMI interrupts. The NMISTAT register is cleared on reset and each time its contents are read. 7 Reserved 1 0 EXT
EXT
The External NMI request bit indicates whether an external non-maskable interrupt request has occurred. Refer to the description of the EXNMI register below for additional details. 0 - No external NMI request. 1 - External NMI request has occurred.
PIN
ENLCK
The EXNMI trap enable bit is one of two bits that can be used to enable NMI interrupts. The bit is cleared by hardware at reset and whenever the NMI interrupt occurs (EXNMI.EXT set). It is intended for applications where the NMI input toggles frequently but nested NMI traps are not desired. For these applications, the EN bit needs to be re-enabled before exiting the trap handler. When used this way, the ENLCK bit should never be set. The EN bit can be set and cleared by software (software can set this bit only if EXNMI.EXT is cleared), and should only be set after the interrupt base register and the interrupt stack pointer have been set up. 0 - NMI interrupts not enabled by this bit (but may be enabled by the ENLCK bit). 1 - NMI interrupts enabled. The PIN bit indicates the state (non-inverted) on the NMI input pin. This bit is read-only, data written into it is ignored. 0 - NMI pin not asserted. 1 - NMI pin asserted. The EXNMI trap enable lock bit is used to permanently enable NMI interrupts. Only a device reset can clear the ENLCK bit. This allows the external NMI feature to be enabled after the interrupt base register and the interrupt stack pointer have been set up. When the ENLCK bit is set, the EN bit is ignored. 0 - NMI interrupts not enabled by this bit (but may be enabled by the EN bit). 1 - NMI interrupts enabled.
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10.3.4
Interrupt Enable and Mask Register 0 (IENAM0)
10.3.7
Interrupt Status Register 0 (ISTAT0)
The IENAM0 register is a word-wide read/write register which holds bits that individually enable and disable the maskable interrupt sources IRQ1 through IRQ15. The register is initialized to FFFFh at reset. 15 IENA 1 0 Res.
The ISTAT0 register is a word-wide read-only register. It indicates which maskable interrupt inputs to the ICU are active. These bits are not affected by the state of the corresponding IENA bits. 15 IST 1 0 Res.
IENA
Each Interrupt Enable bit enables or disables the corresponding interrupt request IRQ1 through IRQ15, for example IENA15 controls IRQ15. Because IRQ0 is not used, IENA0 is ignored. 0 - Interrupt is disabled. 1 - Interrupt is enabled. Interrupt Enable and Mask Register 1 (IENAM1)
IST
The Interrupt Status bits indicate if a maskable interrupt source is signalling an interrupt request. IST15:1 correspond to IRQ15 to IRQ1 respectively. Because the IRQ0 interrupt is not used, bit 0 always reads back 0. 0 - Interrupt is not active. 1 - Interrupt is active. Interrupt Status Register 1 (ISTAT1)
10.3.5
10.3.8
The IENAM1 register is a word-wide read/write register which holds bits that individually enable and disable the maskable interrupt sources IRQ16 through IRQ31. The register is initialized to FFFFh at reset. 15 IENA 0
The ISTAT1 register is a word-wide read-only register. It indicates which maskable interrupt inputs into the ICU are active. These bits are not affected by the state of the corresponding IENA bits. 15 IST 0
IENA
Each Interrupt Enable bit enables or disables the corresponding interrupt request IRQ16 through IRQ31, for example IENA31 controls IRQ31. 0 - Interrupt is disabled. 1 - Interrupt is enabled. Interrupt Enable and Mask Register 2 (IENAM2)
IST
The Interrupt Status bits indicate if a maskable interrupt source is signalling an interrupt request. IST31:16 correspond to IRQ31 to IRQ16, respectively. 0 - Interrupt is not active. 1 - Interrupt is active. Interrupt Status Register 2 (ISTAT2)
10.3.6
10.3.9
The IENAM2 register is a word-wide read/write register which holds bits that individually enable and disable the maskable interrupt sources IRQ32 through IRQ47. The register is initialized to FFFFh at reset. 15 IENA 0
The ISTAT2 register is a word-wide read-only register. It indicates which maskable interrupt inputs into the ICU are active. These bits are not affected by the state of the corresponding IENA bits. 15 IST 0
IENA
Each Interrupt Enable bit enables or disables the corresponding interrupt request IRQ32 through IRQ47, for example IENA47 controls IRQ47. 0 - Interrupt is disabled. 1 - Interrupt is enabled.
IST
The Interrupt Status bits indicate if a maskable interrupt source is signalling an interrupt request. IST47:32 correspond to IRQ47 to IRQ32, respectively. 0 - Interrupt is not active. 1 - Interrupt is active.
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10.4
MASKABLE INTERRUPT SOURCES
Table 20 shows the interrupts assigned to various on-chip maskable interrupts. The priority of simultaneous maskable interrupts is linear, with IRQ47 having the highest priority. Table 20 Maskable Interrupts Assignment IRQ Number IRQ47 IRQ46 IRQ45 IRQ44 IRQ43 IRQ42 IRQ41 IRQ40 IRQ39 IRQ38 IRQ37 IRQ36 IRQ35 IRQ34 IRQ33 IRQ32 IRQ31 IRQ30 IRQ29 IRQ28 IRQ27 IRQ26 IRQ25 IRQ24 IRQ23 IRQ22 IRQ21 IRQ20 IRQ19 IRQ18 IRQ17 IRQ16 IRQ15 www.national.com Description TWM (Timer 0) Reserved Reserved Reserved Reserved Reserved Reserved Reserved DMA Channel 0 DMA Channel 1 DMA Channel 2 DMA Channel 3 CAN0 Advanced Audio Interface (AAI) UART0 RX CVSD/PCM Converter ACCESS.bus TA (Timer input A) TB (Timer input B) VTUA (VTU Interrupt Request 1) VTUB (VTU Interrupt Request 2) VTUC (VTU Interrupt Request 3) VTUD (VTU Interrupt Request 4) Microwire/SPI RX/TX UART0 TX UART0 CTS CAN1 UART1 RX UART1 TX UART2 RX UART2 TX UART3 RX UART3 TX 50
IRQ Number IRQ14 IRQ13 IRQ12 IRQ11 IRQ10 IRQ9 IRQ8 IRQ7 IRQ6 IRQ5 IRQ4 IRQ3 IRQ2 IRQ1 IRQ0 Reserved ADC (Done)
Description
MIWU Interrupt 0 MIWU Interrupt 1 MIWU Interrupt 2 MIWU Interrupt 3 MIWU Interrupt 4 MIWU Interrupt 5 MIWU Interrupt 6 MIWU Interrupt 7 Reserved Random Number Generator (RNG) Reserved Flash Program/Data Memory Reserved
All reserved interrupt vectors should point to default or error interrupt handlers.
10.5
NESTED INTERRUPTS
Nested NMI interrupts are always enabled. Nested maskable interrupts are disabled by default, however an interrupt handler can allow nested maskable interrupts by setting the I bit in the PSR. The LPR instruction is used to set the I bit. Nesting of specific maskable interrupts can be allowed by disabling interrupts from sources for which nesting is not allowed, before setting the I bit. Individual maskable interrupt sources can be disabled using the IENAM0 and IENAM1 registers. Any number of levels of nested interrupts are allowed, limited only by the available memory for the interrupt stack.
CP3CN23
11.0 Triple Clock and Reset
The Triple Clock and Reset module generates a 12 MHz Main Clock and a 32.768 kHz Slow Clock from external crystal networks or external clock sources. It provides various clock signals for the rest of the chip. It also provides the main system reset signal, a power-on reset function, Main
TWM (Invalid Watchdog Service) Flash Interface (Program/Erase Busy) External Reset
Reset
Clock prescalers to generate two additional low-speed clocks, and a 32-kHz oscillator start-up delay. Figure 4 is block diagram of the Triple Clock and Reset module.
Device Reset Reset Module Stretched Reset
Power-On-Reset Module (POR)
Stop Main Osc. Preset X1CKI
Stop Main Osc
Start-Up-Delay 14-Bit Timer
X1CKO High Frequency Oscillator
Good Main Clock
4-Bit Aux1 Prescaler 4-Bit Aux2 Prescaler
Auxiliary Clock 1
Auxiliary Clock 2
Main Clock
Div. by 2
8-Bit Prescaler Mux Slow Clock
Slow Clock Prescaler
Low Frequency Oscillator
X2CKI
Slow Clock Select Start-Up-Delay 8-Bit Timer Time-out Good Slow Clock
X2CKO
Preset Stop Slow Osc Bypass 32 kHz Osc Fast Clock Prescaler 4-Bit Prescaler Mux System Clock
Fast Clock Select Mux PLL Clock
PLL (x3, x4, or x5) Bypass PLL Good PLL Clock Stop PLL Stop PLL DS006
Figure 4. Triple Clock and Reset Module
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11.1
EXTERNAL CRYSTAL NETWORK
X1CKI
An external crystal network is connected to the X1CKI and X1CKO pins to generate the Main Clock, unless an external clock signal is driven on the X1CKI pin. A similar external crystal network may be used at pins X2CKI and X2CKO for the Slow Clock. If an external crystal network is not used for the Slow Clock, the Slow Clock is generated by dividing the fast Main Clock. The crystal network you choose may require external components different from the ones specified in this datasheet. In this case, consult with National's engineers for the component specifications The crystals and other oscillator components must be placed close to the X1CKI/X1CKO and X2CKI/X2CKO device input pins to keep the printed trace lengths to an absolute minimum. Figure 5 shows the external crystal network for the X1CKI and X1CKO pins. Figure 6 shows the external crystal network for the X2CKI and X2CKO pins. Table 21 shows the component specifications for the main crystal network, and Table 22 shows the component specifications for the 32.768 kHz crystal network.
C1
12 MHz Crystal
X1CKO
C2
GND DS189
Figure 5.
Main Clock External Crystal Network
X2CKI
C1
32.768 kHz Crystal X2CKO
C2
GND DS215
Figure 6.
Slow Clock External Crystal Network
Table 21 Component Values of the High Frequency Crystal Circuit Component Crystal Parameters Resonance Frequency Type Max. Serial Resistance Max. Shunt Capacitance Load Capacitance Capacitance Values 12 MHz 20 ppm AT-Cut 50 7 pF 22 pF 22 pF Tolerance
N/A
Capacitor C1, C2
20%
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Table 22 Component Values of the Low Frequency Crystal Circuit Component Crystal Parameters Resonance Frequency Type Maximum Serial Resistance Maximum Shunt Capacitance Load Capacitance Min. Q factor Capacitor C1, C2 Capacitance Values 32.768 kHz Parallel N-Cut or XY-bar 40 k 2 pF 12.5 pF 40000 25 pF Tolerance
N/A
20%
Choose capacitor component values in the tables to obtain the specified load capacitance for the crystal when combined with the parasitic capacitance of the trace, socket, and package (which can vary from 0 to 8 pF). As a guideline, the load capacitance is: C1 x C2 CL = --------------------- + Cparasitic C1 + C2 C2 > C1 C1 can be trimmed to obtain the desired load capacitance. The start-up time of the 32.768 kHz oscillator can vary from one to six seconds. The long start-up time is due to the high Q value and high serial resistance of the crystal necessary to minimize power consumption in Power Save mode.
the Good Slow Clock signal, which indicates that the Slow Clock is stable. For systems that do not require a reduced power consumption mode, the external crystal network may be omitted for the Slow Clock. In that case, the Slow Clock can be synthesized by dividing the Main Clock by a prescaler factor. The prescaler circuit consists of a fixed divide-by-2 counter and a programmable 8-bit prescaler register. This allows a choice of clock divisors ranging from 2 to 512. The resulting Slow Clock frequency must not exceed 100 kHz.
A software-programmable multiplexer selects either the prescaled Main Clock or the 32.768 kHz oscillator as the Slow Clock. At reset, the prescaled Main Clock is selected, ensuring that the Slow Clock is always present initially. Selection of the 32.768 kHz oscillator as the Slow Clock dis11.2 MAIN CLOCK ables the clock prescaler, which allows the CLK1 oscillator The Main Clock is generated by the 12-MHz high-frequency to be turned off, which reduces power consumption and raoscillator or driven by an external signal (typically the diated emissions. This can be done only if the module deLMX5251 RF chip). It can be stopped by the Power Man- tects a toggling low-speed oscillator. If the low-speed agement Module to reduce power consumption during peri- oscillator is not operating, the prescaler remains available ods of reduced activity. When the Main Clock is restarted, a as the Slow Clock source. 14-bit timer generates a Good Main Clock signal after a 11.4 PLL CLOCK start-up delay of 32,768 clock cycles. This signal is an indiThe PLL Clock is generated by the PLL from the 12 MHz cator that the high-frequency oscillator is stable. Main Clock by applying a multiplication factor of x3, x4, or The Stop Main Osc signal from the Power Management x5. Module stops and starts the high-frequency oscillator. When this signal is asserted, it presets the 14-bit timer to To enable the PLL: 3FFFh and stops the high-frequency oscillator. When the 1. Set the PLL multiplication factor in PRFSC.MODE. signal goes inactive, the high-frequency oscillator starts and 2. Clear the PLL power-down bit CRCTRL.PLLPWD. the 14-bit timer counts down from its preset value. When the timer reaches zero, it stops counting and asserts the Good 3. Clear the high-frequency clock select bit CRCTRL.FCLK. Main Clock signal. 4. Read CRCTRL.FCLK, and go back to step 3 if not clear.
11.3
SLOW CLOCK
The CRCTRL.FCLK bit will be clear only after the PLL has The Slow Clock is necessary for operating the device in restabilized, so software must repeat step 3 until the bit is duced power modes and to provide a clock source for modclear. The clock source can be switched back to the Main ules such as the Timing and Watchdog Module. Clock by setting the CRCTRL.FCLK bit. The Slow Clock operates in a manner similar to the Main The PRSFC register must not be modified while the System Clock. The Stop Slow Osc signal from the Power ManageClock is derived from the PLL Clock. The System Clock ment Module stops and starts the low-frequency (32.768 must be derived from the low-frequency oscillator clock kHz) oscillator. When this signal is asserted, it presets a 6while the MODE field is modified. bit timer to 3Fh and disables the low-frequency oscillator. When the signal goes inactive, the low-frequency oscillator starts, and the 6-bit timer counts down from its preset value. When the timer reaches zero, it stops counting and asserts
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CP3CN23
11.5
SYSTEM CLOCK
The System Clock drives most of the on-chip modules, including the CPU. Typically, it is driven by the Main Clock, but it can also be driven by the PLL. In either case, the clock signal is passed through a programmable divider (scale factors from /1 to /16).
rise time. The time constant also should exceed the stabilization time for the high-frequency oscillator.
11.9
CLOCK AND RESET REGISTERS
Table 23 Clock and Reset Registers Name Address FF FC40h FF FC42h FF FC44h FF FC46h Description Clock and Reset Control Register High Frequency Clock Prescaler Register Low Frequency Clock Prescaler Register Auxiliary Clock Prescaler Register
Table 23 lists the clock and reset registers.
11.6
AUXILIARY CLOCKS
Auxiliary Clock 1 and Auxiliary Clock 2 are generated from Main Clock for use by certain peripherals. Auxiliary Clock 1 is available for the Advanced Audio Interface. Auxiliary Clock 2 is available for the CVSD/PCM transcoder and the 12-bit ADC. The Auxiliary clocks may be configured to keep these peripherals running when the System Clock is slowed down or suspended during low-power modes.
CRCTRL PRSFC PRSSC PRSAC 11.9.1
11.7
POWER-ON RESET
The Power-On Reset circuit generates a system reset signal at power-up and holds the signal active for a period of time to allow the crystal oscillator to stabilize. The circuit detects a power turn-on condition, which presets a 14-bit timer driven by Main Clock to a value of 3FFFh. This preset value is defined in hardware and not programmable. Once oscillation starts and the clock becomes active, the timer starts counting down. When the count reaches zero, the 14-bit timer stops counting and the internal reset signal is deactivated (unless the RESET pin is held low). The circuit sets a power-on reset bit on detection of a poweron condition. The CPU can read this bit to determine whether a reset was caused by a power-up or by the RESET input. Note: The Power-On Reset circuit cannot be used to detect a drop in the supply voltage.
Clock and Reset Control Register (CRCTRL)
The CRCTRL register is a byte-wide read/write register that controls the clock selection and contains the power-on reset status bit. At reset, the CRCTRL register is initialized as described below: 7 6 5 4 3 2 1 0
Reserved
POR ACE2 ACE1 PLLPWD FCLK SCLK
SCLK
11.8
EXTERNAL RESET
The active-low RESET input can be used to reset the device at any time. When the signal goes low, it generates an internal system reset signal that remains active until the RESET FCLK signal goes high again. There is no internal pullup on this input, so it must be driven or pulled high externally for proper device operation. If the VCC power supply has slow rise-time. it may be necessary to use an external reset circuit to insure proper device initialization. Figure 7 shows an example of an external reset circuit.
IOVCC IOVCC R
CP3BT2x
PLLPWD
RESET C GND DS216
Figure 7. External Reset Circuit The value of R should be less than 50K ohms. The RC time constant of the circuit should be 5 times the power supply
The Slow Clock Select bit controls the clock source used for the Slow Clock. 0 - Slow Clock driven by prescaled Main Clock. 1 - Slow Clock driven by 32.768 kHz oscillator. The Fast Clock Select bit selects between the 12 MHz Main Clock and the PLL as the source used for the System Clock. After reset, the Main Clock is selected. Attempting to switch to the PLL while the PLLPWD bit is set (PLL is turned off) is ignored. Attempting to switch to the PLL also has no effect if the PLL output clock has not stabilized. 0 - The System Clock prescaler is driven by the output of the PLL. 1 - The System Clock prescaler is driven by the 12-MHz Main Clock. This is the default after reset. The PLL Power-Down bit controls whether the PLL is active or powered down (Stop PLL signal asserted). When this bit is set, the on-chip PLL stays powered-down. Otherwise it is powered-up or it can be controlled by the Power Management Module, respectively. Before software can power-down the PLL in Active mode by setting the PLLPWD bit, the FCLK bit must be set. Attempting to set the PLLPWD bit while the FCLK bit is clear is ignored. The
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CP3CN23
ACE1
ACE2
POR
FCLK bit cannot be cleared until the PLL clock has stabilized. After reset this bit is set. 0 - PLL is active. 1 - PLL is powered down. When the Auxiliary Clock Enable bit is set and a stable Main Clock is provided, the Auxiliary Clock 1 prescaler is enabled and generates the first Auxiliary Clock. When the ACE1 bit is clear or the Main Clock is not stable, Auxiliary Clock 1 is stopped. Auxiliary Clock 1 is used as the clock input for the Advanced Audio Interface. After reset this bit is clear. 0 - Auxiliary Clock 1 is stopped. 1 - Auxiliary Clock 1 is active if the Main Clock is stable. When the Auxiliary Clock Enable 2 bit is set and a stable Main Clock is provided, the Auxiliary Clock 2 prescaler is enabled and generates Auxiliary Clock 2. When the ACE2 bit is clear or the Main Clock is not stable, the Auxiliary Clock 2 is stopped. Auxiliary Clock 2 is used as the clock input for the CVSD/PCM transcoder and the A/D converter. After reset this bit is clear. 0 - Auxiliary Clock 2 is stopped. 1 - Auxiliary Clock 2 is active if the Main Clock is stable. Power-On-Reset - The Power-On-Reset bit is set when a power-turn-on condition has been detected. This bit can only be cleared by software, not set. Writing a 1 to this bit will be ignored, and the previous value of the bit will be unchanged. 0 - Software cleared this bit. 1 - Software has not cleared his bit since the last reset. High Frequency Clock Prescaler Register (PRSFC)
low-frequency oscillator clock while the MODE field is modified. Output Frequency (from 12 MHz input clock) Reserved Reserved Reserved 36 MHz 48 MHz 60 MHz Reserved Reserved
MODE2:0
Description
000 001 010 011 100 101 110 111 11.9.3
Reserved Reserved Reserved 3x Mode 4x Mode 5x Mode Reserved Reserved
Low Frequency Clock Prescaler Register (PRSSC)
The PRSSC register is a byte-wide read/write register that holds the clock divisor used to generate the Slow Clock from the Main Clock. The register is initialized to B6h at reset. 7 SCDIV 0
SCDIV
11.9.2
The PRSFC register is a byte-wide read/write register that holds the 4-bit clock divisor used to generate the high-frequency clock. In addition, the upper three bits are used to control the operation of the PLL. The register is initialized to 4Fh at reset (except in PROG mode.) 7 Res 6 MODE 4 3 FCDIV 0
The Slow Clock Divisor field specifies a divisor to be used when generating the Slow Clock from the Main Clock. The Main Clock is divided by a value of (2 x (SCDIV + 1)) to obtain the Slow Clock. At reset, the SCDIV register is initialized to B6h, which generates a Slow Clock rate of 32786.89 Hz. This is about 0.5% faster than a Slow Clock generated from an external 32768 Hz crystal network. Auxiliary Clock Prescaler Register (PRSAC)
11.9.4
The PRSAC register is a byte-wide read/write register that holds the clock divisor values for prescalers used to generate the two auxiliary clocks from the Main Clock. The register is initialized to FFh at reset. 4 ACDIV2 3 ACDIV2 0
FCDIV
MODE
7 The Fast Clock Divisor specifies the divisor used to obtain the high-frequency System Clock from the PLL or Main Clock. The divisor is (FCDIV + 1). The PLL MODE field specifies the operation ACDIV1 mode of the on-chip PLL. After reset the MODE bits are initialized to 100b, so the PLL is configured to generate a 48-MHz clock. This register must not be modified when the ACDIV2 System Clock is derived from the PLL Clock. The System Clock must be derived from the
The Auxiliary Clock Divisor 1 field specifies the divisor to be used for generating Auxiliary Clock 1 from the Main Clock. The Main Clock is divided by a value of (ACDIV1 + 1). The Auxiliary Clock Divisor 2 field specifies the divisor to be used for generating Auxiliary Clock 2 from the Main Clock. The Main Clock is divided by a value of (ACDIV2 + 1). www.national.com
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CP3CN23
12.0 Power Management
The Power Management Module (PMM) improves the efficiency of the CP3CN23 by changing the operating mode (and therefore the power consumption) according to the required level of device activity. The device implements four power modes: Active Power Save Idle Halt Table 24 summarizes the differences between power modes: the state of the high-frequency oscillator (on or off), the System Clock source (clock used by most modules), and the clock source used by the Timing and Watchdog Module (TWM). The high-frequency oscillator generates the 12-MHz Main Clock, and the low-frequency oscillator generates a 32.768 kHz clock. The Slow Clock can be driven by the 32.768 kHz clock or a scaled version of the Main Clock. Table 24 Power Mode Operating Summary Mode Active High-Frequency Oscillator On System Clock TWM Clock * The Analog/Digital Converter (ADC) module is not automatically disabled by entering Halt mode, however its clock is stopped so no conversions may be performed in Halt mode. For maximum power savings, software must disable the ADC module before entering Halt mode. A module shown as On/Off in Table 25 may be enabled or disabled by software. A module shown as Active continues to operate even while its clock is suspended, which allows wake-up events to be processed during Idle and Halt modes. The Random Number Generator (RNG) module has two oscillators which operate independently of the rest of the system. For maximum power savings, software must disable these oscillators.
12.1
ACTIVE MODE
Main Clock Slow Clock Slow Clock None None Slow Clock Slow Clock None
Power Save On or Off Idle Halt On or Off Off
In Active mode, the high-frequency oscillator is active and generates the 12-MHz Main Clock. The 32.768 kHz oscillator is active and may be used to generate the Slow Clock. The PLL can be active or inactive, as required. Most on-chip modules are driven by the System Clock. The System Clock can be the PLL Clock after a programmable divider or the 12-MHz Main Clock. The activity of peripheral modules is controlled by their enable bits. Power consumption can be reduced in this mode by selectively disabling modules and by executing the WAIT instruction. When the WAIT instruction is executed, the CPU stops executing new instructions until it receives an interrupt signal. After reset, the CP3CN23 is in Active Mode.
The low-frequency oscillator continues to operate in all four modes and power must be provided continuously to the device power supply pins. In Halt mode, however, Slow Clock does not toggle, and as a result, the TWM timer and Watchdog Module do not operate. For the Power Save and Idle modes, the high-frequency oscillator can be turned on or off under software control, as long as the low-frequency oscillator is used to drive Slow Clock. Table 25 shows the clock sources used by the CP3CN23 device modules and their behavior in each power mode. Table 25 Module Activity Summary Power Mode Module Power Active Save On On On On On/Off On On On Idle Off Halt Off Clock Source System System
12.2
POWER SAVE MODE
In Power Save mode, Slow Clock is used as the System Clock which drives the CPU and most on-chip modules. If Slow Clock is driven by the 32.768 kHz oscillator and no onchip module currently requires the 12-MHz Main Clock, software can disable the high-frequency oscillator to further reduce power consumption. Auxiliary Clocks 1 and 2 can be turned off under software control before switching to a reduced power mode, or they may remain active as long as Main Clock is also active. If the system does not require the PLL output clock, the PLL can be disabled. Alternatively, the Main Clock and the PLL can also be controlled by the Hardware Clock Control function, if enabled. The clock architecture is described in Section 11.0. In Power Save mode, some modules are disabled or their operation is restricted. Other modules, including the CPU, continue to function normally, but operate at a reduced clock rate. Details of each module's activity in Power Save mode are described in each module's descriptions. It is recommended to keep CPU activity at a minimum by executing the WAIT instruction to guarantee low power consumption in the system.
CPU MIWU PMM TWM AAI
Active Active On On
Active Slow Clock Off Off Off Off* Off Slow Clock Aux 1 Clock Aux 2 Clock Aux 2 Clock System
On/Off On/Off On/Off
CVSD/PCM On/Off On/Off On/Off ADC All Others On/Off On/Off On/Off On/Off On/Off Off
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CP3CN23
12.3
IDLE MODE
12.6
POWER MANAGEMENT REGISTERS
In Idle mode, the System Clock is disabled and therefore the Table 26 lists the power management registers. clock is stopped to most modules of the device. The PLL Table 26 Power Management Registers and the high-frequency oscillator may be disabled as controlled by register bits. The low-frequency oscillator remains Name Address Description active. The Power Management Module (PMM) and the Timing and Watchdog Module (TWM) continue to operate Power Management PMMCR FF FC60h off the Slow Clock. Auxiliary Clocks 1 and 2 can be turned Control Register off under software control before switching to a power savPower Management ing mode, or they remain active as long as Main Clock is PMMSR FF FC62h Status Register also active. Alternatively, the 12 MHz Main Clock and the PLL can also be controlled by the Hardware Clock Control function, if enabled. 12.6.1 Power Management Control Register (PMMCR)
12.4
The Power Management Control/Status Register (PMMCR) is a byte-wide, read/write register that controls the operating In Halt mode, all the device clocks, including the System power mode (Active, Power Save, Idle, or Halt) and enables Clock, Main Clock, and Slow Clock, are disabled. The highor disables the high-frequency oscillator in the Power Save frequency oscillator and PLL are turned off. The low-freand Idle modes. At reset, the non-reserved bits of this regquency oscillator continues to operate, however its circuitry ister are cleared. The format of the register is shown below. is optimized to guarantee lowest possible power consumption. This mode allows the device to reach the absolute min7 6 5 4 3 2 1 0 imum power consumption without losing its state (memory, registers, etc.). Reserved DHC DMC WBPSM HALT IDLE PSM
HALT MODE
12.5
HIGH-FREQUENCY OSCILLATOR AND PLL CONTROL
Altogether, two mechanisms control whether the high-frequency oscillator is active, and three mechanisms control whether the PLL is active:
PSM
Disable Bits: The DMC and DHC bits in the PMMCR register may be used to disable the high-frequency oscillator and PLL, respectively, in Power Save and Idle modes. When used to disable the high-frequency oscillator or PLL, the DMC and DHC bits override the HCC mechanism. Power Management Mode: Halt mode disables the high-frequency oscillator and PLL. Active Mode enables them. The DMC and DHC bits and the HCC mechanism IDLE have no effect in Active or Halt mode. PLL Power Down Bit: The PLLPWD bit in the CRCTRL register can be used to disable the PLL in all modes. This bit does not affect the high-frequency oscillator.
If the Power Save Mode bit is clear and the WBPSM bit is clear, writing 1 to the PSM bit causes the device to start the switch to Power Save mode. If the WBPSM bit is set when the PSM bit is written with 1, entry into Power Save mode is delayed until execution of a WAIT instruction. The PSM bit becomes set after the switch to Power Save mode is complete. The PSM bit can be cleared by software, and it can be cleared by hardware when a hardware wake-up event is detected. 0 - Device is not in Power Save mode. 1 - Device is in Power Save mode. The Idle Mode bit indicates whether the device has entered Idle mode. The WBPSM bit must be set to enter Idle mode. When the IDLE bit is written with 1, the device enters IDLE mode at the execution of the next WAIT instruction. The IDLE bit can be set and cleared by software. It is also cleared by the hardware when a hardware wake-up event is detected. 0 - Device is not in Idle mode. 1 - Device is in Idle mode.
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CP3CN23
HALT
WBPSM
The Halt Mode bit indicates whether the de- DMC vice is in Halt mode. Before entering Halt mode, the WBPSM bit must be set. When the HALT bit is written with 1, the device enters the Halt mode at the execution of the next WAIT instruction. When in HALT mode, the PMM stops the System Clock and then turns off the PLL and the high-frequency oscillator. The HALT bit can be set and cleared by software. The Halt mode is exited by a hardware wake-up event. When this signal is set high, the oscillator is started. After the oscillator has stabilized, the HALT bit is cleared by the hardware. DHC 0 - Device is not in Halt mode. 1 - Device is in Halt mode. When the Wait Before Power Save Mode bit is clear, a switch from Active mode to Power Save mode only requires setting the PSM bit. When the WBPSM bit is set, a switch from Active mode to Power Save, Idle, or Halt mode is performed by setting the PSM, IDLE or HALT bit, respectively, and then executing a WAIT instruction. Also, if the DMC or DHC bits are set, the high-frequency oscillator and PLL may be disabled only after a WAIT instruction is executed and the Power Save, Idle, or Halt mode is entered. 0 - Mode transitions may occur immediately. 1 - Mode transitions are delayed until the next WAIT instruction is executed.
The Disable Main Clock bit may be used to disable the high-frequency oscillator in Power Save and Idle modes. In Active mode, the high-frequency oscillator is enabled without regard to the DMC value. In Halt mode, the high-frequency oscillator is disabled without regard to the DMC value. The DMC bit is cleared by hardware when a hardware wakeup event is detected. 0 - High-frequency oscillator is only disabled in Halt mode or when disabled by the HCC mechanism. 1 - High-frequency oscillator is also disabled in Power Save and Idle modes. The Disable High-Frequency (PLL) Clock bit and the CRCTRL.PLLPWD bit may be used to disable the PLL in Power Save and Idle modes. When the DHC bit is clear (and PLLPWD = 0), the PLL is enabled in these modes. If the DHC bit is set, the PLL is disabled in Power Save and Idle mode. In Active mode with the CRCTRL.PLLPWD bit set, the PLL is enabled without regard to the DHC value. In Halt mode, the PLL is disabled without regard to the DMC value. The DHC bit is cleared by hardware when a hardware wake-up event is detected. 0 - PLL is disabled only by entering Halt mode or setting the CRCTRL.PLLPWD bit. 1 - PLL is also disabled in Power Save or Idle mode.
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CP3CN23
12.6.2
Power Management Status Register (PMMSR)
12.7
SWITCHING BETWEEN POWER MODES
The Management Status Register (PMMR) is a byte-wide, read/write register that provides status signals for the various clocks. The reset value of PMSR register bits 0 to 2 depend on the status of the clock sources monitored by the PMM. The upper 5 bits are clear after reset. The format of the register is shown below. 7 Reserved 3 2 1 0 OLC
Switching from a higher to a lower power consumption mode is performed by writing an appropriate value to the Power Management Control/Status Register (PMMCR). Switching from a lower power consumption mode to the Active mode is usually triggered by a hardware interrupt. Figure 8 shows the four power consumption modes and the events that trigger a transition from one mode to another.
Reset WBPSM = 1 & HAL = 1 & T "WAIT" Active Mode WBPSM = 0 & PSM = 1 or WBPSM = 1 & PSM = 1 & "WAIT"
OHC OMC
OLC
OMC
OHC
The Oscillating Low Frequency Clock bit indicates whether the low-frequency oscillator is producing a stable clock. When the low-frequency oscillator is unavailable, the PMM will not switch to Power Save, Idle, or Halt mode. 0 - Low-frequency oscillator is unstable, disabled, or not oscillating. 1 - Low-frequency oscillator is available. The Oscillating Main Clock bit indicates whether the high-frequency oscillator is producing a stable clock. When the high-frequency oscillator is unavailable, the PMM will not switch to Active mode. 0 - High-frequency oscillator is unstable, disabled, or not oscillating. 1 - High-frequency oscillator is available. The Oscillating High Frequency (PLL) Clock bit indicates whether the PLL is producing a stable clock. Because the PMM tests the stability of the PLL clock to qualify power mode state transitions, a stable clock is indicated when the PLL is disabled. This removes the stability of the PLL clock from the test when the PLL is disabled. When the PLL is enabled but unstable, the PMM will not switch to Active mode. 0 - PLL is enabled but unstable. 1 - PLL is stable or disabled (CRCTRL.PLLPWD = 0).
WBPSM = 1 & IDLE = 1 & "WAIT"
Power Save Mode
HW Event
WBPSM = 1 & IDLE = 1 & "WAIT"
Idle Mode IDLE = 1
HW Event
Halt Mode Note: HW Event = MIWU wake-up or NMI
HW Event DS008
Figure 8. Power Mode State Diagram Some of the power-up transitions are based on the occurrence of a wake-up event. An event of this type can be either a maskable interrupt or a non-maskable interrupt (NMI). All of the maskable hardware wake-up events are monitored by the Multi-Input Wake-Up (MIWU) Module, which is active in all modes. Once a wake-up event is detected, it is latched until an interrupt acknowledge cycle occurs or a reset is applied. A wake-up event causes a transition to the Active mode and restores normal clock operation, but does not start execution of the program. It is the interrupt handler associated with the wake-up source (MIWU or NMI) that causes program execution to resume. 12.7.1 Active Mode to Power Save Mode
A transition from Active mode to Power Save mode is performed by writing a 1 to the PMMCR.PSM bit. The transition to Power Save mode is either initiated immediately or at execution of the next WAIT instruction, depending on the state of the PMMCR.WBPSM bit. For an immediate transition to Power Save mode (PMMCR.WBPSM = 0), the CPU continues to operate using the low-frequency clock. The PMMCR.PSM bit becomes set when the transition to the Power Save mode is completed. For a transition at the next WAIT instruction (PMMCR.WBPSM = 1), the CPU continues to operate in Active mode until it executes a WAIT instruction. At execution of the WAIT instruction, the device enters the Power Save mode, and the CPU waits for the next interrupt event. In this case, the PMMCR.PSM bit becomes set when it is written, even before the WAIT instruction is executed.
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CP3CN23
12.7.2
Entering Idle Mode
12.7.6
Wake-Up Transition to Active Mode
Entry into Idle mode is performed by writing a 1 to the PM- A hardware wake-up event switches the device directly from MCR.IDLE bit and then executing a WAIT instruction. The Power Save, Idle, or Halt mode to Active mode. Hardware PMMCR.WBPSM bit must be set before the WAIT instruc- wake-up events are: tion is executed. Idle mode can be entered only from the AcNon-Maskable Interrupt (NMI) tive or Power Save mode. Valid wake-up event on a Multi-Input Wake-Up channel 12.7.3 Disabling the High-Frequency Clock When a wake-up event occurs, the on-chip hardware perWhen the low-frequency oscillator is used to generate the forms the following steps: Slow Clock, power consumption can be reduced further in 1. Clears the PMMCR.DMC bit, which enables the highthe Power Save or Idle mode by disabling the high-frequenfrequency clock (if it was disabled). cy oscillator. This is accomplished by writing a 1 to the PM- 2. Waits for the PMMSR.OMC bit to become set, which inMCR.DHC bit before executing the WAIT instruction that dicates that the high-frequency clock is operating and puts the device in the Power Save or Idle mode. The highis stable. frequency clock is turned off only after the device enters the 3. Clears the PMMCR.DHC bit, which enables the PLL. Power Save or Idle mode. 4. Waits for the PMMSR.OHC bit to become set. The CPU operates on the low-frequency clock in Power 5. Switches the device into Active mode. Save mode. It can turn off the high-frequency clock at any 12.7.7 Power Mode Switching Protection time by writing a 1 to the PMMCR.DHC bit. The high-frequency oscillator is always enabled in Active mode and al- The Power Management Module has several mechanisms ways disabled in Halt mode, without regard to the to protect the device from malfunctions caused by missing or unstable clock signals. PMMCR.DHC bit setting. Immediately after power-up and entry into Active mode, software must wait for the low-frequency clock to become stable before it can put the device in Power Save mode. It should monitor the PMMSR.OLC bit for this purpose. Once this bit is set, Slow Clock is stable and Power Save mode can be entered. 12.7.4 Entering Halt Mode The PMMSR.OHC, PMMSR.OMC, and PMMSR.OLC bits indicate the current status of the PLL, high-frequency oscillator, and low-frequency oscillator, respectively. Software can check the appropriate bit before switching to a power mode that requires the clock. A set status bit indicates an operating, stable clock. A clear status bit indicates a clock that is disabled, not available, or not yet stable. (Except in the case of the PLL, which has a set status bit when disabled.) During a power mode transition, if there is a request to switch to a mode with a clear status bit, the switch is delayed until that bit is set by the hardware.
Entry into Halt mode is accomplished by writing a 1 to the PMMCR.HALT bit and then executing a WAIT instruction. The PMMCR.WBPSM bit must be set before the WAIT instruction is executed. Halt mode can be entered only from Active or Power Save mode. 12.7.5
When the system is built without an external crystal network Software-Controlled Transition to Active Mode for the low-frequency clock, Main Clock is divided by a presA transition from Power Save mode to Active mode can be caler factor to produce the low-frequency clock. In this situaccomplished by either a software command or a hardware ation, Main Clock is disabled only in the Halt mode, and wake-up event. The software method is to write a 0 to the cannot be disabled for the Power Save or Idle mode. PMMCR.PSM bit. The value of the register bit changes only after the transition to the Active mode is completed. Without an external crystal network for the low-frequency clock, the device comes out of Halt or Idle mode and enters If the high-frequency oscillator is disabled for Power Save Active mode with Main Clock driving Slow Clock. operation, the oscillator must be enabled and allowed to sta- Note: For correct operation in the absence of a low-frebilize before the transition to Active mode. To enable the quency crystal, the X2CKI pin must be tied low (not left floathigh-frequency oscillator, software writes a 0 to the PM- ing) so that the hardware can detect the absence of the MCR.DMC bit. Before writing a 0 to the PMMCR.PSM bit, crystal. software must first monitor the PMMSR.OMC bit to determine when the oscillator has stabilized.
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CP3CN23
13.0 Multi-Input Wake-Up
The Multi-Input Wake-Up (MIWU) unit consists of two identical 16-channel modules. Each module can assert a wakeup signal for exiting from a low-power mode, and each can assert an interrupt request on any of four Interrupt Control Unit (ICU) channels assigned to that module. The modules operate independently, so each may assert an interrupt request to the ICU. Together, these modules provide 32 MIWU input channels and 8 interrupt request outputs. Each 16-channel module monitors its inputs for a softwareselectable trigger condition. On detection of a trigger condition, the module generates an interrupt request and if enabled, a wake-up request. A wake-up request can be used by the power management unit to exit the Halt, Idle, or Power Save mode and return to the Active mode. An interrupt request generates an interrupt to the CPU, which allows an interrupt handler to respond to MIWU events. rupt handler. Therefore, setting up the MIWU interrupt handler is essential for any wake-up operation. Each 16-channel module has four interrupt requests that can be routed to the ICU as shown in Figure 9. Each of the 16 channels can be programmed to activate one of these four interrupt requests. The 32 MIWU channels are named WUI0 through WUI31, as shown in Table 27. Each channel can be configured to trigger on rising or falling edges, as determined by the setting in the WK0EDG or WK1EDG register. Each trigger event is latched into the WK0PND or WK1PND register. If a trigger event is enabled by its respective bit in the WK0ENA or WK1ENA register, an active wake-up/interrupt signal is generated. Software can determine which channel has generated the active signal by reading the WK0PND or WK1PND register.
The wake-up event only activates the clocks and CPU, but does not by itself initiate execution of any code. It is the in- The MIWU is active at all times, including the Halt mode. All terrupt request asserted by the MIWU that gets the CPU to device clocks are stopped in this mode. Therefore, detecting start executing code, by jumping to the corresponding inter- an external trigger condition and the subsequent setting of the pending bit are not synchronous to the System Clock.
Peripheral Bus
15
........... WK0IENA WK1IENA
0
WK0ICTL1/WK0ICTL2 WK1ICTL1/WK1ICTL2
WUI0 WUI16
0 4 MIWU Interrupt 3:0 MIWU Interrupt 7:4
Encoder
WUI15 WUI31 WK0EDG WK1EDG
15 WK0PND WK1PND
Wake-Up Signal To Power Mgt
WK0ENA WK1ENA 15 ........... 0 DS218
Figure 9. Multi-Input Wake-Up Module Block Diagram
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13.1
Table 27 MIWU Sources MIWU Channel WUI0 WUI1 WUI2 WUI3 WUI4 WUI5 WUI6 WUI7 WUI8 WUI9 WUI10 WUI11 WUI12 WUI13 WUI14 WUI15 WUI16 WUI17 WUI18 WUI19 WUI20 WUI21 WUI22 WUI23 WUI24 WUI25 WUI26 WUI27 WUI28 WUI29 WUI30 WUI31 Source TWM T0OUT ACCESS.bus CAN0RX MWCS UART0 CTS UART0 RXD Reserved AAI SFS Reserved PJ7 PG6 PH0 PH1 PH2 PH3 PH4 PH5 PH6 PJ0 PJ1 PJ2 PJ3 PJ4 PJ5 PJ6 Reserved UART1 RXD UART2 RXD UART3 RXD Reserved ADC Done CAN1RX
MULTI-INPUT WAKE-UP REGISTERS
Table 28 lists the MIWU registers. Table 28 Multi-Input Wake-Up Registers Name Address Description Wake-Up Edge Detection Register Module 0 Wake-Up Edge Detection Register Module 1 Wake-Up Enable Register Module 0 Wake-Up Enable Register Module 1 Wake-Up Interrupt Control Register 1 Module 0 Wake-Up Interrupt Control Register 1 Module 1 Wake-Up Interrupt Control Register 2 Module 0 Wake-Up Interrupt Control Register 2 Module 1 Wake-Up Pending Register Module 0 Wake-Up Pending Register Module 1 Wake-Up Pending Clear Register Module 0 Wake-Up Pending Clear Register Module 1 Wake-Up Interrupt Enable Register Module 0 Wake-Up Interrupt Enable Register Module 1
WK0EDG
FF FC80h
WK1EDG
FF FCA0h
WK0ENA
FF FC82h
WK1ENA
FF FCA2h
WK0ICTL1
FF FC84h
WK1ICTL1
FF FCA4h
WK0ICTL2
FF FC86h
WK1ICTL2
FF FCA6h
WK0PND
FF FC88h
WK1PND
FF FCA8h
WK0PCL
FF FC8Ah
WK1PCL
FF FCAAh
WK0IENA
FF FC8Ch
WK1IENA
FF FCACh
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13.1.1
Wake-Up Edge Detection Register (WK0EDG)
13.1.4
Wake-Up 1 Enable Register (WK1ENA)
The WK0EDG register is a word-wide read/write register that controls the edge sensitivity of the MIWU channels. The WK0EDG register is cleared upon reset, which configures all channels to be triggered on rising edges. The register format is shown below. 15 WKED 0
The WK1ENA register is a word-wide read/write register that individually enables or disables wake-up events from the MIWU channels. The WK1ENA register is cleared upon reset, which disables all wake-up/interrupt channels. The register format is shown below. 15 WKEN 0
WKED
The Wake-Up Enable bits enable and disable The Wake-Up Edge Detection bits control the WKEN the MIWU channels. The WKEN15:0 bits coredge sensitivity for MIWU channels. The respond to the WUI31:16 channels, respecWKED15:0 bits correspond to the WUI15:0 tively. channels, respectively. 0 - MIWU channel wake-up events disabled. 0 - Triggered on rising edge (low-to-high transition). 1 - MIWU channel wake-up events enabled. 1 - Triggered on falling edge (high-to-low 13.1.5 Wake-Up Interrupt Enable Register (WK0IENA) transition). The WK0IENA register is a word-wide read/write register 13.1.2 Wake-Up 1 Edge Detection Register (WK1EDG) that enables and disables interrupts from the MIWU chanThe WK1EDG register is a word-wide read/write register nels. The register format is shown below. that controls the edge sensitivity of the MIWU channels. The WK1EDG register is cleared upon reset, which configures 15 0 all channels to be triggered on rising edges. The register forWKIEN mat is shown below. 15 WKED 0
WKIEN
WKED
The Wake-Up Edge Detection bits control the edge sensitivity for MIWU channels. The WKED15:0 bits correspond to the WUI31:16 channels, respectively. 0 - Triggered on rising edge (low-to-high transition). 1 - Triggered on falling edge (high-to-low transition). Wake-Up Enable Register (WK0ENA)
The Wake-Up Interrupt Enable bits control whether MIWU channels generate interrupts. The WKIEN15:0 bits correspond to the WUI15:0 channels, respectively. 0 - Interrupt disabled. 1 - Interrupt enabled. Wake-Up 1 Interrupt Enable Register (WK1IENA)
13.1.6
The WK1IENA register is a word-wide read/write register that enables and disables interrupts from the MIWU channels. The register format is shown below. 15 WKIEN 0
13.1.3
The WK0ENA register is a word-wide read/write register that individually enables or disables wake-up events from the MIWU channels. The WK0ENA register is cleared upon reset, which disables all wake-up/interrupt channels. The register format is shown below. 15 WKEN 0
WK1IEN
The Wake-Up Interrupt Enable bits control whether MIWU channels generate interrupts. The WKIEN15:0 bits correspond to the WUI31:16 channels, respectively. 0 - Interrupt disabled. 1 - Interrupt enabled.
WKEN
The Wake-Up Enable bits enable and disable the MIWU channels. The WKEN15:0 bits correspond to the WUI15:0 channels, respectively. 0 - MIWU channel wake-up events disabled. 1 - MIWU channel wake-up events enabled.
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13.1.7
Wake-Up Interrupt Control Register 1 (WK0ICTL1)
13.1.9
Wake-Up Interrupt Control Register 2 (WK0ICTL2)
The WK0ICTL1 register is a word-wide read/write register that selects the interrupt request signal for the associated MIWU channels WUI7:0. At reset, the WK0ICTL1 register is cleared, which selects MIWU Interrupt Request 0 for all eight channels. The register format is shown below. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
The WK0ICTL2 register is a word-wide read/write register that selects the interrupt request signal for the associated MIWU channels WUI15:8. At reset, the WK2ICTL2 register is cleared, which selects MIWU Interrupt Request 0 for all eight channels. The register format is shown below. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
WKIN WKIN WKIN WKIN WKIN WKIN WKIN WKIN TR7 TR6 TR5 TR4 TR3 TR2 TR1 TR0
WKIN WKIN WKIN WKIN WKIN WKIN WKIN WKIN TR15 TR14 TR13 TR12 TR11 TR10 TR9 TR8
WKINTR
The Wake-Up Interrupt Request Select fields WKINTR select which of the four MIWU interrupt requests are activated for the corresponding channel. 00 - Selects MIWU interrupt request 0. 01 - Selects MIWU interrupt request 1. 10 - Selects MIWU interrupt request 2. 11 - Selects MIWU interrupt request 3. Wake-Up 1 Interrupt Control Register 1 (WK1ICTL1)
The Wake-Up Interrupt Request Select fields select which of the four MIWU interrupt requests are activated for the corresponding channel. 00 - Selects MIWU interrupt request 0. 01 - Selects MIWU interrupt request 1. 10 - Selects MIWU interrupt request 2. 11 - Selects MIWU interrupt request 3.
13.1.8
13.1.10 Wake-Up 1 Interrupt Control Register 2 (WK1ICTL2) The WK1ICTL2 register is a word-wide read/write register that selects the interrupt request signal for the associated MIWU channels WUI31:24. At reset, the WK1ICTL2 register is cleared, which selects MIWU Interrupt Request 4 for all eight channels. The register format is shown below. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
The WK1ICTL1 register is a word-wide read/write register that selects the interrupt request signal for the associated MIWU channels WUI23:16. At reset, the WK1ICTL1 register is cleared, which selects MIWU Interrupt Request 4 for all eight channels. The register format is shown below. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
WKIN WKIN WKIN WKIN WKIN WKIN WKIN WKIN TR23 TR22 TR21 TR20 TR19 TR18 TR17 TR16
WKIN WKIN WKIN WKIN WKIN WKIN WKIN WKIN TR31 TR30 TR29 TR28 TR27 TR26 TR25 TR24
WKINTR
The Wake-Up Interrupt Request Select fields WKINTR select which of the four MIWU interrupt requests are activated for the corresponding channel. 00 - Selects MIWU interrupt request 4. 01 - Selects MIWU interrupt request 5. 10 - Selects MIWU interrupt request 6. 11 - Selects MIWU interrupt request 7.
The Wake-Up Interrupt Request Select fields select which of the four MIWU interrupt requests are activated for the corresponding channel. 00 - Selects MIWU interrupt request 4. 01 - Selects MIWU interrupt request 5. 10 - Selects MIWU interrupt request 6. 11 - Selects MIWU interrupt request 7.
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13.1.11 Wake-Up Pending Register (WK0PND) The WK0PND register is a word-wide read/write register in which the Multi-Input Wake-Up module latches any detected trigger conditions. The CPU can only write a 1 to any bit position in this register. If the CPU attempts to write a 0, it has no effect on that bit. To clear a bit in this register, the CPU must use the WK0PCL register. This implementation prevents a potential hardware-software conflict during a read-modify-write operation on the WK0PND register. This register is cleared upon reset. The register format is shown below. 15 WKPD 0
13.1.13 Wake-Up Pending Clear Register (WK0PCL) The WK0PCL register is a word-wide write-only register that lets the CPU clear bits in the WKPND register. Writing a 1 to a bit position in the WKPCL register clears the corresponding bit in the WKPND register. Writing a 0 has no effect. Do not modify this register with instructions that access the register as a read-modify-write operand, such as the bit manipulation instructions. Reading this register location returns undefined data. Therefore, do not use a read-modify-write sequence (such as the SBIT instruction) to set individual bits. Do not attempt to read the register, then perform a logical OR on the register value. Instead, write the mask directly to the register address. The register format is shown below. 15 0 WKCL
WKPD
The Wake-Up Pending bits indicate which MIWU channels have been triggered. The WKPD15:0 bits correspond to the WUI15:0 channels. Writing 1 to a bit sets it. WKCL 0 - Trigger condition did not occur. 1 - Trigger condition occurred.
13.1.12 Wake-Up 1 Pending Register (WK1PND) The WK1PND register is a word-wide read/write register in which the Multi-Input Wake-Up module latches any detected trigger conditions. The CPU can only write a 1 to any bit position in this register. If the CPU attempts to write a 0, it has no effect on that bit. To clear a bit in this register, the CPU must use the WK1PCL register. This implementation prevents a potential hardware-software conflict during a read-modify-write operation on the WK1PND register. This register is cleared upon reset. The register format is shown below. 15 WKPD 0
Writing 1 to a bit clears it. 0 - Writing 0 has no effect. 1 - Writing 1 clears the corresponding bit in the WKPD register.
13.1.14 Wake-Up 1 Pending Clear Register (WK1PCL) The WK1PCL register is a word-wide write-only register that lets the CPU clear bits in the WK1PND register. Writing a 1 to a bit position in the WK1PCL register clears the corresponding bit in the WK1PND register. Writing a 0 has no effect. Do not modify this register with instructions that access the register as a read-modify-write operand, such as the bit manipulation instructions. Reading this register location returns undefined data. Therefore, do not use a read-modify-write sequence (such as the SBIT instruction) to set individual bits. Do not attempt to read the register, then perform a logical OR on the register value. Instead, write the mask directly to the register address. The register format is shown below. 0 WKCL
WKPD
15 The Wake-Up Pending bits indicate which MIWU channels have been triggered. The WKPD15:0 bits correspond to the WUI31:15 channels. Writing 1 to a bit sets it. 0 - Trigger condition did not occur. WKCL 1 - Trigger condition occurred.
Writing 1 to a bit clears it. 0 - Writing 0 has no effect. 1 - Writing 1 clears the corresponding bit in the WK1PD register.
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13.2
PROGRAMMING PROCEDURES
To set up and use the Multi-Input Wake-Up function, use the following procedure. Performing the steps in the order shown will prevent false triggering of a wake-up condition. This same procedure should be used following a reset because the wake-up inputs are left floating, resulting in unknown data on the input pins. 1. Clear the WK0ENA and WK1ENA registers to disable the MIWU channels. 2. Write the WK0EDG and WK1EDG registers to select the desired type of edge sensitivity (clear for rising edge, set for falling edge). 3. Set all bits in the WK0PCL and WK0PCL registers to clear any pending bits in the WK0PND and WK1PND registers. 4. Set up the WK0ICTL1, WK1ICTL1, WK0ICTL2, and WK1ICTL2 registers to define the interrupt request signal used for each channel. 5. Set the bits in the WK0ENA and WK1ENA registers corresponding to the wake-up channels to be activated. To change the edge sensitivity of a wake-up channel, use the following procedure. Performing the steps in the order shown will prevent false triggering of a wake-up/interrupt condition. 1. Clear the WK0ENA or WK1ENA bit associated with the input to be reprogrammed. 2. Write the new value to the corresponding bit position in the WK0EDG or WK1EDG register to reprogram the edge sensitivity of the input. 3. Set the corresponding bit in the WK0PCL or WK1PCL register to clear the pending bit in the WK0PND or WK1PND register. 4. Set the same WK0ENA or WK1ENA bit to re-enable the wake-up function.
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14.0 Input/Output Ports
Each device has up to 50 software-configurable I/O pins, organized into 8-bit ports (not all bits are used in some ports). The ports are named Port B, Port C, Port E, Port F, Port G, Port H, and Port J. In addition to their general-purpose I/O capability, the I/O pins of Ports E, F, G, H, and J have alternate functions for use with on-chip peripheral modules such as the UART or the Multi-Input Wake-Up unit. The alternate functions of all I/O pins are shown in Table 83. Ports B and C are used as the 16-bit data bus when an external bus is enabled (144-pin devices only). This alternate function is selected by enabling the DEV or ERE operating environments, not by programming the port registers. Different pins within the same port can be individually configured to operate in different modes. Figure 10 is a diagram showing the I/O port pin logic. The register bits, multiplexers, and buffers allow the port pin to be configured into the various operating modes. The output buffer is a TRI-STATE buffer with weak pull-up capability. The weak pull-up, if used, prevents the port pin from going to an undefined state when it operates as an input. To reduce power consumption, input buffers configured for general-purpose I/O are only enabled when they are read. When configured for an alternate function, the input buffers are enabled continuously. To minimize power consumption, input signals to enabled buffers must be held within 0.2 volts of the VCC or GND voltage.
The I/O pin characteristics are fully programmable. Each pin can be configured to operate as a TRI-STATE output, push- The electrical characteristics and drive capabilities of the inpull output, weak pull-up input, or high-impedance input. put and output buffers are described in Section 28.0.
D PxALTS Register
Q
D PxALT Register
Q
VCC
D PxWKPU Register
Q
Weak Pull-Up Enable
Alt. A Device Direction Alt. B Device Direction D PxDIR Register Pin Alt. A Device Data Outout Alt. B Device Data Outout D PxDOUT Register Q Data Out Q Output Enable
Alt. A Data Input PxDIN Register Alt. B Data Input 1 Data In Read Strobe Data In
Analog Input
DS190
Figure 10.
I/O Port Pin Logic PxALT: Port alternate function register PxALTS: Port alternate function select register PxDIR: Port direction register PxDIN: Port data input register PxDOUT: Port data output register PxWPU: Port weak pull-up register PxHDRV: Port high drive strength register
14.1
PORT REGISTERS
Each port has an associated set of memory-mapped registers used for controlling the port and for holding the port data:
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Table 29 Port Registers Table 29 Port Registers Name PBALT PBDIR PBDIN PBDOUT PBWPU PBHDRV PBALTS PCALT PCDIR PCDIN PCDOUT PCWPU PCHDRV PCALTS PEALT PEDIR PEDIN PEDOUT PEWPU PEHDRV PEALTS PFALT PFDIR PFDIN PFDOUT PFWPU Address FF FB00h FF FB02h FF FB04h FF FB06h FF FB08h FF FB0Ah FF FB0Ch FF FB10h FF FB12h FF FB14h FF FB16h FF FB18h FF FB1Ah FF FB1Ch FF FCC0h FF FCC2h FF FCC4h FF FCC6h FF FCC8h FF FCCAh FF FCCCh FF FCE0h FF FCE2h FF FCE4h FF FCE6h FF FCE8h Description PFHDRV Port B Alternate Function Register PFALTS Port B Direction Register Port B Data Input Register Port B Data Output Register Port B Weak Pull-Up Register Port B High Drive Strength Register Port B Alternate Function Select Register PGHDRV Port C Alternate Function Register PGALTS Port C Direction Register Port C Data Input Register Port C Data Output Register Port C Weak Pull-Up Register Port C High Drive Strength Register Port C Alternate Function Select Register PHHDRV Port E Alternate Function Register PHALTS Port E Direction Register Port E Data Input Register Port E Data Output Register Port E Weak Pull-Up Register Port E High Drive Strength Register Port E Alternate Function Select Register PJHDRV Port F Alternate Function Register PJALTS Port F Direction Register Port F Data Input Register Port F Data Output Register Port F Weak Pull-Up Register FF F34Ch FF F34Ah PJALT PJDIR PJDIN PJDOUT PJWPU FF F340h FF F342h FF F344h FF F346h FF F348h FF F32Ch FF F32Ah PHALT PHDIR PHDIN PHDOUT PHWPU FF F320h FF F322h FF F324h FF F326h FF F328h FF F30Ch FF F30Ah PGALT PGDIR PGDIN PGDOUT PGWPU FF F300h FF F302h FF F304h FF F306h FF F308h FF FCECh FF FCEAh Name Address Description Port F High Drive Strength Register Port F Alternate Function Select Register Port G Alternate Function Register Port G Direction Register Port G Data Input Register Port G Data Output Register Port G Weak Pull-Up Register Port G High Drive Strength Register Port G Alternate Function Select Register Port H Alternate Function Register Port H Direction Register Port H Data Input Register Port H Data Output Register Port H Weak Pull-Up Register Port H High Drive Strength Register Port H Alternate Function Select Register Port J Alternate Function Register Port J Direction Register Port J Data Input Register Port J Data Output Register Port J Weak Pull-Up Register Port J High Drive Strength Register Port J Alternate Function Select Register
In the descriptions of the ports and port registers, the lowercase letter "x" represents the port designation, either B, C, E, F, G, H, or J. For example, "PxDIR register" means any one of the port direction registers: PBDIR, PCDIR, PEDIR, PFDIR, PGDIR, PHDIR, or PJDIR.
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All of the port registers are byte-wide read/write registers, except for the port data input registers, which are read-only registers. Each register bit controls the function of the corresponding port pin. For example, PGDIR.2 (bit 2 of the PGDIR register) controls the direction of port pin PG2. 14.1.1 Port Alternate Function Register (PxALT)
14.1.3
Port Data Input Register (PxDIN)
The data input register (PxDIN) is a read-only register that returns the current state on each port pin. The CPU can read this register at any time even when the pin is configured as an output. 7 PxDIN 0
The PxALT registers control whether the port pins are used for general-purpose I/O or for their alternate function. Each port pin can be controlled independently.
A clear bit in the alternate function register causes the corThe PxDIN bits indicate the state on the corresponding pin to be used for general-purpose I/O. In this PxDIN responding port pin. configuration, the output buffer is controlled by the direction 0 - Pin is low. register (PxDIR) and the data output register (PxDOUT). 1 - Pin is high. The input buffer is visible to software as the data input register (PxDIN). 14.1.4 Port Data Output Register (PxDOUT) A set bit in the alternate function register (PxALT) causes The data output register (PxDOUT) holds the data to be the corresponding pin to be used for its peripheral I/O funcdriven on output port pins. In this configuration, writing to tion. When the alternate function is selected, the output the register changes the output value. Reading the register buffer data and TRI-STATE configuration are controlled by returns the last value written to the register. signals from the on-chip peripheral device. A reset operation leaves the register contents unchanged. A reset operation clears the port alternate function regisAt power-up, the PxDOUT registers contain unknown valters, which initializes the pins as general-purpose I/O ports. ues. This register must be enabled before the corresponding alternate function is enabled. 7 0 7 PxALT PxDOUT PxALT The PxDOUT bits hold the data to be driven on pins configured as outputs in general-purpose I/O mode. 0 - Drive the pin low. 1 - Drive the pin high. 0 PxDOUT
The PxALT bits control whether the corresponding port pins are general-purpose I/O ports or are used for their alternate function by an on-chip peripheral. 14.1.5 Port Weak Pull-Up Register (PxWPU) 0 - General-purpose I/O selected. 1 - Alternate function selected. The weak pull-up register (PxWPU) determines whether the port pins have a weak pull-up on the output buffer. The pull14.1.2 Port Direction Register (PxDIR) up device, if enabled by the register bit, operates in the genThe port direction register (PxDIR) determines whether eral-purpose I/O mode whenever the port output buffer is each port pin is used for input or for output. A clear bit in this disabled. In the alternate function mode, the pull-ups are alregister causes the corresponding pin to operate as an inways disabled. put, which puts the output buffer in the high-impedance state. A set bit causes the pin to operate as an output, which A reset operation clears the port weak pull-up registers, which disables all pull-ups. enables the output buffer. A reset operation clears the port direction registers, which initializes the pins as inputs. 7 PxDIR 0 PxWPU The PxWPU bits control whether the weak pull-up is enabled. 0 - Weak pull-up disabled. 1 - Weak pull-up enabled. 7 PxWPU 0
PxDIR
The PxDIR bits select the direction of the corresponding port pin. 0 - Input. 1 - Output.
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14.1.6
Port High Drive Strength Register (PxHDRV)
Table 30 Port Pin PF5 PF6 PF7 PG0
Alternate Function Select PxALTS = 0 SFS STD SRD Reserved Reserved Reserved Reserved Reserved Reserved WUI10 TA UART1 RXD1 UART1 TXD1 UART2 RXD2 UART2 TXD2 UART3 RXD3 UART3 TXD3 CAN0RX CAN0TX WUI18 WUI19 WUI20 WUI21 WUI22 WUI23 WUI24 ASYNC PxALTS = 1 TIO6 TIO7 TIO8 Reserved Reserved SRCLK Reserved Reserved Reserved Reserved Reserved WUI11 WUI12 WUI13 WUI14 WUI15 WUI16 WUI17 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved WUI9
The PxHDRV register is a byte-wide, read/write register that controls the slew rate of the corresponding pins. The high drive strength function is enabled when the corresponding bits of the PxHDRV register are set. In both GPIO and alternate function modes, the drive strength function is enabled by the PxHDRV registers. At reset, the PxHDRV registers are cleared, making the ports low speed. 7 PxHDRV 0
PG1 PG2
PxHDRV
The PxHDRV bits control whether output pins are driven with slow or fast slew rate. 0 - Slow slew rate. 1 - Fast slew rate. Port Alternate Function Select Register (PxALTS)
PG3 PG4 PG5 PG6 PG7 PH0 PH1 PH2
14.1.7
The PxALTS register selects which of two alternate functions are selected for the port pin. These bits are ignored unless the corresponding PxALT bits are set. Each port pin can be controlled independently. 7 PxALTS 0
PH3 PH4 PH5
PxALTS
The PxALTS bits select among two alternate functions. Table 30 shows the mapping of the PxALTS bits to the alternate functions. Unused PxALTS bits must be clear. Table 30 Alternate Function Select Port Pin PE0 PE1 PE2 PE3 PE4 PE5 PE6 PE7 PF0 PF1 PF2 PF3 PF4 PxALTS = 0 UART0 RXD0 UART0 TXD0 UART0 RTS UART0 CTS UART0 CKX SRFS CAN1RX CAN1TX MSK MDIDO MDODI MWCS SCK PxALTS = 1 Reserved Reserved Reserved Reserved TB NMI Reserved Reserved TIO1 TIO2 TIO3 TIO4 TIO5
PH6 PH7 PJ0 PJ1 PJ2 PJ3 PJ4 PJ5 PJ6 PJ7
14.2
OPEN-DRAIN OPERATION
A port pin can be configured to operate as an inverting open-drain output buffer. To do this, the CPU must clear the bit in the data output register (PxDOUT) and then use the port direction register (PxDIR) to set the value of the port pin. With the direction register bit set (direction = out), the value zero is forced on the pin. With the direction register bit clear (direction = in), the pin is placed in the TRI-STATE mode. If desired, the internal weak pull-up can be enabled to pull the signal high when the output buffer is in TRISTATE mode.
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15.0 12-Bit Analog to Digital Converter
The integrated 12-bit ADC provides the following features: 8-input analog multiplexer 8 single-ended channels or 4 differential channels External filtering capability 12-bit resolution with 11-bit accuracy Sign bit
MUXOUT0 MUXOUT1 ADCIN
15-microsecond conversion time Support for resistive touchscreen interface Internal or external start trigger Programmable start delay after start trigger Poll or interrupt on done
VREFP AVCC ADC0 ADC1 AGND ADC2 ADC3
Pen-Down Detector ADC0/TSX+ DRV ADC1/TSYDRV ADC2/TSXDRV ADC3/TSY+ DRV ADC4 ADCIN 12 Pen Down ADC7 Wake-Up (WUI30) Input + Multiplexer Int/Ext Multiplexer VREFP + 12-BIT ADC Clock Control Result VREFN PREF_CFG NREF_CFG
TOUCH_CFG
MUX_CFG ADC Clock
ADC_DIV
Start
ADC SEQUENCER
Done
Interrupt (IRQ13)
ASYNC TRIGGER DELAY1
CLKDIV
DELAY2
4-Word FIFO
ADC_CONTROL
ADC_DELAY1
CLKSEL
ADC_DELAY2
ADCRESLT System Bus Interface DS183
System Clock
Auxiliary Clock 2
Figure 11.
Analog to Digital Converter Block Diagram 12-Bit ADC--receives the output of the Internal/External Multiplexer and performs the analog to digital conversion. ADCRESLT Register--makes conversion results from the 12-Bit ADC available to the on-chip bus. The ADCRESLT register includes the software-visible end of a 4word FIFO used to queue conversion results. The configuration of the analog signal paths is controlled by fields in the ADCGCR register. The Input Multiplexer is controlled by the MUX_CFG field. The Internal/External Multiplexer is controlled by the ADCIN bit. The analog multiplexers for selecting the voltage references used by the ADC are controlled by the PREF_CFG and NREF_CFG fields. The low-ohmic drivers used for interface to resistive touchscreens are controlled by the TOUCH_CFG field.
15.1
FUNCTIONAL DESCRIPTION
The ADC module consists of a 12-bit ADC converter and associated state machine, together with analog multiplexers to set up signal paths for sampling and voltage references, logic to control triggering of the converter, and a bus interface. 15.1.1 Data Path
Up to 8 GPIO pins may be configured as 8 singled-ended analog inputs or 4 differential pairs. Analog/digital data passes through four main blocks in the ADC module between the input pins and the CPU bus: Input Multiplexer--an analog multiplexer that selects among the input channels. Internal/External Multiplexer--an analog multiplexer that selects between the output of the Input Multiplexer and the ADCIN external analog input.
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The output of the Input Multiplexer is available externally as the MUXOUT0 and MUXOUT1 signals. In single-ended mode, only MUXOUT0 is used. In differential mode, MUXOUT0 is the positive side and MUXOUT1 is the negative side. The MUXOUT0 and MUXOUT1 outputs and the ADCIN external analog input are provided so that external signal conditioning circuits (such as filters) may be applied to the analog signals before conversion. The MUXOUT0, MUXOUT1, and ADCIN signals are alternate functions of GPIO pins used by the Input Multiplexer, so the number of available analog input channels is reduced when these signals are used. 15.1.2 Operation
one system clock after the ADCRESLT register is read). Total conversion time is around 15 microseconds. The Done signal is also an input to the Multi-Input Wake-Up unit (WUI30). The MIWU input is asserted whenever the FIFO is not empty (but will deassert for one system clock after the ADCRESLT register is read). The wake-up output is provided so that the ADC module can bring the system out of a power-saving mode when a conversion operation is completed. It asserts earlier than the interrupt output. In the pen-down detection mode of the ADC, the wake-up output is ORed with the ADC pen-down detector output, to wake up on a pen-down event. 15.1.3 ADC Clock Generation
The TRIGGER block may be configured to initiate a conversion from either of these sources: External ASYNC Input--an edge on the ASYNC input triggers a conversion. This input may be configured to be sensitive to rising or falling edges, as controlled by the POL bit in the ADCCNTRL register. ADCSTART Register--writing any value to the ADCSTART register triggers a conversion. The TRIGGER block incorporates a glitch filter to suppress transient spikes on the ASYNC input. The TRIGGER block will recognize ASYNC pulse widths of 10 ns or greater. Once a trigger event has been recognized, no further triggering is recognized until the conversion is completed.
The DELAY2 block generates ADC Clock, which is the clock used internally by the ADC module. ADC Clock is derived from either: System Clock--a programmable divider is available to generate the 12 MHz clock required by the ADC from the System Clock. Auxiliary Clock 2--may be used to perform conversions when the System Clock is slowed down or suspended in low-power modes.
The DELAY2 block receives the clock source selected by the CLKSEL bit of the ADCACR register and adds a number of asynchronous incremental delay units specified in the ADC_DELAY2 field of the ADCSCDLY register. This deWhen the ASYNC input is selected as the trigger source, it layed clock (ADC Clock) then drives the TRIGGER, 12-BIT may be configured for automatic or non-automatic mode, as ADC, and ADC SEQUENCER blocks. ADC Clock also controlled by the AUTO bit in the ADCCNTRL register: drives the ADC_DIV clock divider, which generates the Automatic Mode--a conversion is triggered by any clock which drives the DELAY1 block. qualified edge on the ASYNC input (unless a conversion Because the ADCRESLT FIFO is driven by System Clock is already in progress). (not ADC Clock), a conversion result will not propagate to Non-Automatic Mode--before a conversion may be the output of the FIFO when the System Clock is suspendtriggered from the ASYNC input, software must "prime" ed. the TRIGGER block by writing the ADCSTART register. 15.1.4 ADC Voltage References Once the TRIGGER block is primed, a conversion is triggered by any qualified edge on the ASYNC input. After The 12-BIT ADC block has positive and negative voltage the conversion is completed, no additional trigger events reference inputs, VREFP and VREFN. In single-ended will be recognized until software once again primes the mode, only VREFP is used. An analog multiplexer allows selecting an external VREFP pin, the analog supply voltage TRIGGER block by writing the ADCSTART register. AVCC, or the analog inputs ADC0 or ADC1 as the positive Once a trigger event is recognized, the DELAY1 block waits voltage reference, as controlled by the PREF_CFG field of for a programmable delay specified in the ADC_DELAY1 the ADCGCR register. Another analog multiplexer allows field of the ADCSCDLY register. Then, it asserts the Start selecting the analog ground AGND or the analog inputs signal to the ADC SEQUENCER block. ADC2 or ADC3 as the negative voltage reference, as conWhen the Start signal is received, the ADC SEQUENCER trolled by the NREF_CFG field of the ADCGCR register. block initiates the conversion in the 12-Bit ADC. After the conversion is complete, the result is loaded into the FIFO, 15.1.5 Pen-Down Detector and the Done signal is asserted. The ADCRESLT register includes the software-visible end of a 4-word FIFO, which allows up to 4 conversion results to be queued for reading. Reading the ADCRESLT register unloads the FIFO. If the FIFO overflows, a bit is set in the ADCRESLT register, and the most recent conversion data is lost. The Done signal is visible to software as the ADC_DONE bit in the ADCRESLT register. The Done signal is also an input to the interrupt controller (IRQ13). The interrupt will be asserted whenever the FIFO is not empty (but will deassert for www.national.com 72 A pen-down detector is provided on the ADC0 (TSX+) input of the ADC. It consists of a Schmitt-trigger receiver, with a minimum Vil of 0.7V. When pen-down detect mode is enabled by loading 101b into the TOUCH_CFG field of the ADCGCR register, the output of this detector is visible to software in the PEN_DOWN bit of the ADCRESLT register, and this output is ORed with the Done signal to become the wake-up input (WUI30) to the Multi-Input Wake-Up unit.
CP3CN23
15.2
TOUCHSCREEN INTERFACE
15.2.1
Touchscreen Driver Configuration
The ADC provides an interface for 4-wire resistive touchscreens with the resolution necessary for applications such as signature analysis. A typical touchscreen configuration is shown in Figure 12.
An equivalent circuit for the touchscreen interface is shown in Figure 13.
VCC
TSX+/ADC0 TSY+/ADC1 TSX-/ADC2 TSY-/ADC3
6
6 TSY+ TSX+ X Plate RX1 Y Plate RY1 RZ B
To ADC
A
MUXOUT0 ADCIN DS186 TSXTSY6 6
RX2
RY2
Figure 12. Touchscreen Interface
A touchscreen consists of two resistive plates normally separated from each other. The TSX+ and TSX- signals are connected to opposite ends of the X plate, while the TSY+ and TSY- signals are connected to the Y plate. If the pen is DS187 down, the plates will be shorted together at the point of pen contact. The location of the pen is sensed by driving one Figure 13. Touchscreen Driver Equivalent Circuit end of a plate to VCC, driving the opposite end to ground, and sensing the voltage at the point of pen contact using the Low-ohmic drivers are provided to pull the TSX+ and TSY+ signals to VCC and the TSX- and TSY- signals to GND. The other plate. This is done twice, once for each coordinate. on-resistance of these drivers is specified to be 6 ohms. An external RC low-pass filter is used to remove noise couTwo measurements are used to produce one (x,y) position pled to the touchscreen signals from the display drivers. coordinate pair. To measure the x-coordinate, the TSX+ signal is pulled to VCC, the TSX- signal is pulled to GND, and the TSY+ and TSY- signals are undriven. A voltage divider is formed across the X plate, with the center tap of the divider being the point of pen contact, represented in Figure 13 by node A. With TSY+ and TSY- undriven, the voltage at node A can be measured by sampling either of the TSY+ or TSY- signals. This voltage will be proportional to the position of the pen contact on the X plate. The position of the pen contact on the Y plate is measured similarly, by driving the TSY+ signal to VCC, the TSY- signal to GND, and leaving the TSX+ and TSX- signals undriven. The voltage at node B can be sampled from either the TSX+ or TSX- signals. The TOUCH_CFG field of the ADCGCR register specifies the configuration of the drivers, with 010b used to sample node A and 001b used to sample node B. Typically, two consecutive measurements are made of each coordinate so that any interference coupled from the LCD column drivers is averaged out. The plate-to-plate resistance is shown in Figure 13 as RZ. This measurement is used as an indication of the force of pen contact. When 100b is loaded into the TOUCH_CFG field, the TSY+ signal is pulled to VCC and the TSX- signal is pulled to GND, to support measuring RZ.
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15.2.2
Measuring Pen Force
Solving for RY1, the resistance is: B RY1 = RYP x 1 - ------------ 2047 Now that the resistance values RX2 and RY1 are known, it is possible to calculate the value of the plate-to-plate contact resistance, RZ, given the value measured at node C on the TSX+ input in Sample Z mode. Node C is a tap in a resistor-divider network composed of three resistors, such that: C RX2 ------------ = --------------------------------------------2047 RY1 + RZ + RX2 Solving for RZ, the resistance is: 2047 - C RZ = RX2 x ---------------------- - RY1 C The resistance RZ is proportional to the force of pen contact. 15.2.3 Compensation for Driver Resistance
Figure 14 shows equivalent circuits for the driver modes used to measure the X, Y, and Z coordinates, in which Z represents pen force. In this discussion, the ohmic resistance of the drivers is neglected (see Section 15.2.3), and series resistance between the node of interest and the ADC is ignored because it has no significant effect.
VCC
VCC
VCC
RY1
RX1 A RX2
RY1 B RY2
RZ C RX2
Sample X TOUCH_CFG = 001
Sample Y TOUCH_CFG = 010
Sample Z TOUCH_CFG = 100 DS188
Figure 14.
Touchscreen Driver Modes
In the following examples, the ADC is assumed to operate in single-ended mode to produce conversion values between 0 and 2047, however the same principles could be extended to differential mode to recover the full range of the ADC. In Sample X mode, the X plate is driven between VCC and ground, so that a value measured at node A on the TSY+ or TSY- inputs is the center tap of a resistor-divider network. The end-to-end resistance RXP of the X plate is: RXP = RX1 + RX2
Plate resistances between opposite electrodes range from 100 ohms to 1k ohm. Because of the 6-ohm driver resistance, some significant voltage drop will be experienced between, for example, TSX- and AGND. A 200-ohm plate will drop: 6 ---------------------------- x ( AVCC - AGND ) 200 + 6 + 6 With a 2.5V supply, this is 70 mV. A 12-bit ADC has 4096 possible values, so each value covers a range of 610 V at 2.5V. A voltage drop of 70 mV across each of the low-ohmic drivers reduces the number of available ADC values by: 70 mV x 2 -------------------------- = 230 610 uV
This effective loss of resolution can be handled in a number The value measured at node A is proportional to the ratio of ways. between the resistance to ground and the resistance of the 1. The voltages on, for example, TSY+ and TSY- can be X plate: sampled before sampling TSX+ and TSX-. Then, scalA RX2 ing can be applied in software to convert the samples ------------ = -----------2047 RXP to the full (4096-bit) range. This technique will not recover any resolution, however it is worthy of some conSolving for RX2, the resistance is: sideration because touchscreen data is typically A RX2 = RXP x ------------ passed to two applications: 2047 Signature Analysis--only the raw data is required. No absolute positioning is necessary. Similarly, in Sample Y mode the value measured at node B Screen Overlay--for example, for cursor positioning. on the TSX+ or TSX- inputs is proportional to the ratio beIn this application, a scaling or calibration is performed tween the resistance to ground and the resistance RYP of to correctly overlay the touchscreen coordinates onto the Y plate: the display. Because of this calibration, it is not even B RY2 ------------ = -----------necessary to sample TSY+ and TSY-. 2047 RYP 2. The ADC has a positive voltage reference input which Because end-to-end resistance RYP of the Y plate is: can be internally connected to the TSY+ terminal. This means that the number of available ADC values is inRYP = RY1 + RY2 creased to: The previous equation can be rewritten as: 70 mV 4096 - ------------------- = 3981 B RYP - RY1 610 uV ------------ = -----------------------------2047 RYP Software scaling could be applied to this value if required (as with technique 1, above), but no additional resolution is achieved. www.national.com 74
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3. By extension, the ADC negative voltage reference can be internally connected to the TSY- terminal, to recover the full 4096 values. The Global Configuration Register (ADCGCR) provides the flexibility to implement any of these techniques.
15.5
ADC REGISTER SET
Table 31 ADC Registers Name Address FF F3C0h FF F3C2h FF F3C4h FF F3C6h FF F3C8h FF F3CAh Description ADC Global Configuration Register ADC Auxiliary Configuration Register ADC Conversion Control Register ADC Start Conversion Register ADC Start Conversion Delay Register ADC Result Register
Table 31 lists the ADC registers.
15.3
ADC OPERATION IN POWER-SAVING MODES
ADCGCR ADCACR ADCCNTRL ADCSTART ADCSCDLY ADCRESLT
To reduce the level of switching noise in the environment of the ADC, it is possible to operate the CP3CN23 in low-power modes, in which the System Clock is slowed or switched off. Under these conditions, Auxiliary Clock 2 can be selected as the clock source for the ADC module, however conversion results cannot be read by the system while the System Clock is suspended. The expected operation in power-saving modes is therefore: 1. ADC is configured and a conversion is primed or triggered. 2. A power-saving mode is entered. 3. ADC conversion completes and a wake-up signal is asserted to the MIWU unit. 4. Device wakes up and processes the conversion result. To conserve power, the ADC should be disabled before entering a low-power mode if its function is not required.
15.4
FREEZE
The ADC module provides support for an In-System Emulator by means of a special FREEZE input. When FREEZE is asserted the module will exhibit the following specific behavior: The automatic clear-on-read function of the result register (ADCRESLT) is disabled. The FIFO is updated as usual, and an interrupt for a completed conversion can be asserted.
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15.5.1
ADC Global Configuration Register (ADCGCR) MUX_CFG
The ADCGCR register controls the basic operation of the interface. The CPU bus master has read/write access to the ADCGCR register. After reset this register is set to 0000h. 8 7 6 5 4 3 2 1 0
The Multiplexer Configuration field and the DIFF bit configure the analog circuits of the ADC module, as shown in Table 32. Table 32 MUX_CFG Operation Channels Selected (DIFF = 1) + 1 0
TOUCH_CFG
MUX_CFG
DIFF ADCIN CLKEN
MUX_CFG
Channel Selected, (DIFF = 0) 0 1
15
14
13
12
11
10
9 000 001 0 1
MUXOUTEN INTEN Res.
NREF_CFG
PREF_CFG
CLKEN
ADCIN
DIFF
010 2 2 3 The Clock Enable bit controls whether the ADC module is running. When this bit is clear, 011 3 3 2 all ADC clocks are disabled, the ADC analog circuits are in a low-power state, and ADC 100 4 4 5 registers (other than the ADCGCR and AG101 5 5 4 CACR registers) are not writeable. Clearing this bit reinitializes the ADC state machine 110 6 6 7 and cancels any pending trigger event. When 111 7 7 6 this bit is set, the ADC clocks are enabled and the ADC analog circuits are powered up. The converter is operational within 0.25 s of beFor best noise immunity in touchscreen appliing enabled. cations, channel 2 should be used for sam0 - ADC disabled. pling the X plate voltage, and channel 1 1 - ADC enabled. should be used for sampling the Y plate voltThe ADCIN bit selects the source of the ADC age. input. When the bit is clear, the source is the TOUCH_CFG The Touchscreen Configuration field controls 8-channel Input Multiplexer. When the bit is the configuration of the low-ohmic drivers for set, the source is the ADCIN pin. the TSX+, TSX-, TSY+, and TSY- signals, as 0 - ADC input is from 8-channel multiplexer. shown in Table 33. When TOUCH_CFG is 1 - ADC input is from ADCIN pin. 101b, the pen-down detector is enabled. The The Differential Operation Mode bit and the output of the pen-down detector is visible to MUX_CFG field configure the analog circuits software in the PEN_DOWN bit of the ADof the ADC module. When this bit is clear, the SRESLT register, and it is ORed with the ADC module operates in single-ended mode. Done signal to generate the wake-up signal When this bit is set, the ADC operates in difWUI30 passed to the MIWU unit. ferential mode. See Table 32 . 0 - Single-ended mode. 1 - Differential mode. Table 33 TOUCH_CFG Modes ADC2/TSXInactive Inactive Driven Low Inactive Driven Low Inactive Inactive ADC3/TSYInactive Driven Low Inactive Driven Low Inactive Driven Low inactive Mode None Sample Y Sample X Sample Z (1), Pre-Pen Down Sample Z (2) Pen-Down Detect Reserved
TOUCH_CFG 000 001 010 011 100 101 11X
ADC0/TSX+ Inactive Inactive Driven High Driven High Inactive Weakly Pulled High Inactive
ADC1/TSY+ Inactive Driven High Inactive Inactive Driven High Inactive Inactive
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PREF_CFG The Positive Voltage Reference Configuration field specifies the source of the ADC positive voltage reference, according to the following table: PREF_CFG 00 01 10 11 PREF Source Internal (AVCC) VREFP ADC0 ADC1
15.5.2
ADC Auxiliary Configuration Register (ADCACR)
The ADCACR register is used to control the clock configuration and report the status of the ADC module. The CPU bus master has read/write access to the ADCACR register. After reset, this register is clear. 15 14 13 PRM 12 3 2 1 0
CNVT TRG
Reserved
CLKDIV CLKSEL
CLKSEL
NREF_CFG The Negative Voltage Reference Configuration field specifies the source of the ADC negative voltage reference, according to the following table: NREF_CFG 00 01 10 11 NREF source Internal (AGND) Reserved ADC2 ADC3
CLKDIV
The Clock Select bit selects the clock source used by the DELAY2 block to generate the ADC clock. 0 - ADC clock derived from System Clock. 1 - ADC clock derived from Auxiliary Clock 2. The Clock Divisor field specifies the divisor applied to System Clock to generate the 12 MHz clock required by the ADC module. Only the System Clock is affected by this divisor. The divisor is not used when Auxiliary Clock 2 is selected as the clock source. CLKDIV 00 01 10 11 Clock Divisor 1 2 4 Reserved
MUXOUTEN The MUXOUT Enable bit controls whether the output of the Input Multiplexer is available externally. In single-ended mode, the MUXOUT0 pin is active and the MUXOUT1 pin is disabled (TRI-STATE). In differential mode, both MUXOUT0 and MUXOUT1 are PRM active. 0 - MUXOUT0 and MUXOUT1 disabled. 1 - MUXOUT0 and MUXOUT1 enabled. INTEN The Interrupt Enable bit controls whether the ADC interrupt (IRQ13) is enabled. When enabled, the interrupt request is asserted when valid data is available in the ADCRESLT reg- TRG ister. This bit has no effect on the wake_up signal to the MIWU unit (WUI30). 0 - IRQ13 disabled. 1 - IRQ13 enabled. CNVT
The ADC Primed bit is a read-only bit that indicates the ADC has been primed to perform a conversion by writing to the ADCSTART register. The bit is cleared after the conversion is completed. 0 - ADC has not been primed. 1 - ADC has been primed. The ADC Triggered bit is a read-only bit that indicates the ADC has been triggered. The bit is set during any pre-conversion delay. The bit is cleared after the conversion is completed. 0 - ADC has not been triggered. 1 - ADC has been triggered. The ADC Conversion bit is a read-only bit that indicates the ADC has been primed to perform a conversion, a valid internal or external trigger event has occurred, any pre-conversion delay has expired, and the ADC conversion is in progress. The bit is cleared after the conversion is completed. 0 - ADC is not performing a conversion. 1 - ADC conversion is in progress.
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15.5.3
ADC Conversion Control Register (ADCCNTRL)
15.5.4
ADC Start Conversion Register (ADCSTART)
The ADCCNTRL register specifies the trigger conditions for an ADC conversion. 15 Reserved 3 2 1 0 POL
The ADCSTART register is a write-only register used by software to initiate an ADC conversion. Writing any value to this register will cause the ADC to initiate a conversion or prime the ADC to initiate a conversion, as controlled by the ADCCNTRL register. 15.5.5 ADC Start Conversion Delay Register (ADCSCDLY)
AUTO EXT
POL
EXT
AUTO
The ASYNC Polarity bit specifies the polarity of edges which trigger ADC conversions. 0 - ASYNC input is sensitive to rising edges. 1 - ASYNC input is sensitive to falling edges. The External Trigger bit selects whether conversions are triggered by writing the ADCSTART register or activity on the ASYNC input. 0 - ADC conversions triggered by writing to the ADCSTART register. 1 - ADC conversions triggered by qualified edges on ASYNC input. The Automatic bit controls whether automatic mode is enabled, in which any qualified edge on the ASYNC input is recognized as a trigger event. When automatic mode is disabled, the ADC module must be "primed" before a qualified edge on the ASYNC input can trigger a conversion. To prime the ADC module, software must write the ADCSTART register with any value before an edge on the ASYNC input is recognized as a trigger event. After the conversion is completed, the ASYNC input will be ignored until software again writes the ADCSTART register. The AUTO bit is ignored when the EXT bit is 0. 0 - Automatic mode disabled. 1 - Automatic mode enabled.
The ADCSCDLY register controls critical timing parameters for the operation of the ADC module. 15 14 13 5 4 0
ADC_DIV
ADC_DELAY1
ADC_DELAY2
ADC_DELAY2 The ADC Delay 2 field specifies the delay between the ADC module clock source (either System Clock after a programmable divider or Auxiliary Clock 2) and the ADC clock. The range of effective values for this field is 0 to 20. Values above 20 produce the same delay as 20, which is about 42 ns. ADC_DELAY1 The ADC Delay 1 field specifies the number of clock periods by which the trigger event will be delayed before initiating a conversion. The timebase for this delay is the ADC clock (12 MHz) divided by the ADC_DIV divisor. The ADC_DELAY1 field has 9 bits, which corresponds to a maximum delay of 511 clock periods. ADC_DIV The ADC Clock Divisor field specifies the divisor applied to the ADC clock (12 MHz) to generate the clock used to drive the DELAY1 block. A field value of n results in a division ratio of n+1. With a module clock of 12 MHz, the maximum delay which can be provided by ADC_DIV and ADC_DELAY settings is: 1 ------------------- x 4 x 511 = 170 us 12 MHz
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15.5.6
ADC Result Register (ADCRESLT)
The ADCRESLT register includes the software-visible end of a 4-word FIFO. Conversion results are loaded into the FIFO from the 12-bit ADC and unloaded when software reads the ADCRESLT register. The ADCRESLT register is read-only. With the exception of the PEN_DOWN bit, the fields in this register are cleared when the register is read. 11 ADC_RESULT 0
15
14
13
12 SIGN
ADC_DONE ADC_OFLW PEN_DOWN
ADC_RESULT The ADC Result field holds a 12-bit value for the conversion result. If the ADC_DONE bit is clear, there is no valid result in this field, and the field will have a value of 0. The ADC_RESULT field and the SIGN bit together form the software-visible end of the ADC FIFO. SIGN The Sign bit indicates whether the - input has a voltage greater than the + input (differential mode only). For example if ADCGCR.MUX_CFG is 000b, ADC0 is the + input and ADC1 is the - input. If the voltage on ADC0 is greater than the voltage on ADC1, the SIGN bit will be 0; if the voltage on ADC0 is less than the voltage on ADC1, the SIGN bit will be 1. In single-ended mode, this bit always reads as 0. 0 - In differential mode, + input has a voltage greater than the - input. In single-ended mode, this bit is always 0. 1 - In differential mode, - input has a voltage greater than the + input.
PEN_DOWN The Pen-Down bit indicates whether a pendown condition is being sensed. To enable pen-down detection, the TOUCH_CFG field of the ADCGCR register must be loaded with 101b. When pen-down detection is enabled and a pen-down condition is sensed, the PEN_DOWN bit is set. This bit is not carried through the FIFO, so its value represents the current status of the pen-down detector. When pen-down detection is enabled, the signal from the pen-down detector is ORed with the Done signal to generate the wake-up signal (WUI30) passed to the MIWU unit. If pendown detection is not enabled, this bit reads as 0. 0 - No pen-down condition is sensed, or pendown detection is disabled. 1 - Pen-down condition is sensed. ADC_OFLW The ADC FIFO Overflow bit indicates whether the 4-word FIFO behind the ADCRESLT register has overflowed. When this occurs, the most recent conversion result is lost. This bit is cleared when the ADCRESLT register is read. 0 - FIFO overflow has not occurred. 1 - FIFO overflow has occurred. ADC_DONE The ADC Done bit indicates when an ADC conversion has completed. When this bit is set, the data in the ADC_RESULT field is valid. When this bit is clear, there is no valid data in the ADC_RESULT field. The Done bit is cleared when the ADCRESLT register is read, but if there are queued conversion results in the FIFO, the Done bit will become set again after one System Clock period. 0 - No ADC conversion has completed since the ADCRESLT register was last read. 1 - An ADC conversion has completed since the ADCRESLT register was last read.
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16.0 Random Number Generator (RNG)
The RNG unit is a hardware "true random" number generator. When enabled, this unit provides up to 800 random bits per second. The bits are available for reading from a 16-bit register. The RNG unit includes two oscillators which operate independently of the System Clock: When a new 16-bit word of random data is available, it is loaded into the RNGD register. If enabled, an interrupt request (IRQ3) is asserted when the word is available for reading. When software reads the RNGD register, the register is cleared and the interrupt request is deasserted.
The RNGCST register provides control and status bits for Fast Oscillator--a 24 MHz oscillator which drives a lin- the RNG module: ear feedback shift register (LFSR). RNG Enable--enables or disables the RNG oscillators. Slow Oscillator--an unstable oscillator which drives a Interrupt Mask--enables or disables the interrupt when flip-flop for sampling the pseudorandom bitstream from a new word of random data becomes available. the LFSR. This oscillator operates at approximately 115 Data Valid--indicates whether a new word is available. kHz, but it does not have a fixed frequency.
By sampling the pseudorandom bitstream at random intervals, a random bitstream is synthesized. This bitstream is clocked into a 16-bit shift register. A programmable clock divider generates the clock signal for the shift register from the System Clock.
16.1
FREEZE
The RNG module provides support for an In-System Emulator by means of a special FREEZE input. When FREEZE is asserted, the automatic clear-on-read function of the RNDGD register is disabled.
RNGCST Q Enable Fast Osc. (~24 MHz) Clock 31-Bit LFSR D Q Sample Flip-Flop Clock D 16-Bit Shift Register Clock
Slow Osc. (~115 kHz) (Unstable) RNGDIVH/RNGDIVL
RNGD
System Bus
System Clock
Sample Strobe Divider DS185
Figure 15. RNG Module Block Diagram
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16.2
RANDOM NUMBER GENERATOR REGISTER SET
Table 34 RNG Registers Name Address FF F280h FF F282h FF F284h FF F286h Description RNG Control and Status Register RNG Data Register RNG Divisor Register High RNG Divisor Register Low
16.2.2
RNG Data Register (RNGD)
Table 31 lists the RNG registers.
The RNGD register holds random data generated by the RNG module. After reading the register, it is cleared and the DVALID bit of the RNGCST register is cleared. When a new word of valid (random) data becomes available in the RNGD register, the DVALID bit is set and (if enabled) and interrupt request is asserted. 15 RNGD15:0 0
RNGCST RNGD RNGDIVH RNGDIVL 16.2.1
16.2.3
RNG Divisor Register High (RNGDIVH)
This register holds the two most significant bits of the RNGDIV clock divisor. See the description of the RNGDIVL register. 15 Reserved 2 1 0
RNG Control and Status Register (RNGCST) RNGDIV17:16
The RNGCST register provides control and status bits for the RNG module. This register is cleared at reset. 15 Reserved 6 5 IMSK 4 Reserved 2 1 0
16.2.4
RNG Divisor Register Low (RNGDIVL)
DVALID RNGE
This register holds the 16 least significant bits the RNGDIV clock divisor. 15 RNGDIV15:0 0
RNGE
DVALID
IMASK
The Random Number Generator Enable bit enables the operation of the RNG. When this bit is clear, the RNG module is disabled, and both RNG oscillators are suspended. 0 - RNG module disabled. 1 - RNG module enabled. The Data Valid bit indicates whether valid (random) data is available in the RNGD register. This bit is cleared when the RNGD register is read. 0 - RNGD register holds invalid data. 1 - RNGD register holds valid data. The Interrupt Mask bit controls whether an interrupt request (IRQ3) will be asserted when valid (random) data is available in the RNGD register. 0 - RNG interrupt disabled. 1 - RNG interrupt enabled.
The RNGDIV clock divisor is used to generate the sampling strobe for loading random bits into the shift register. The divisor is applied to the System Clock source. The maximum frequency after division is 800 Hz. For example, a System Clock frequency of 24 MHz would require an RNGDIV value of 30,000 (7530h) or greater. The default RNGDIV value is 0000 83D6h.
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17.0 CAN Module
Each of the two CAN modules provides a Full CAN class, CAN (Controller Area Network) serial bus interface for low/ high speed applications. They support reception and transmission of extended frames with a 29-bit identifier, standard frames with an 11-bit identifier, applications that require high speed (up to 1 MBit/s), and a low-speed CAN interface with CAN master capability. Data transfer between the CAN bus and the CPU is handled by 15 message buffers, which can be individually configured as receive or transmit buffers. Every message buffer includes a status/control register which provides information about its current status and capabilities to configure the buffer. All message buffers are able to generate an interrupt on the reception of a valid frame or the successful transmission of a frame. In addition, an interrupt can be generated on bus errors. An incoming message is only accepted if the message identifier passes one of two acceptance filtering masks. The filtering mask can be configured to receive a single message ID for each buffer or a group of IDs for each receive buffer. One of the buffers uses a separate message filtering procedure. This provides the capability to establish a BASIC-CAN path. Remote transmission requests can be processed automatically by automatic reconfiguration to a receiver after transmission or by automated transmit scheduling upon reception. A priority decoder allows any buffer to have one of 16 transmit priorities including the highest or lowest absolute priority, for a total of 240 different transmit priorities. A decided bit time counter (16-bit wide) is provided to support real time applications. The contents of this counter are captured into the message buffer RAM on reception or transmission. The counter can be synchronized through the CAN network. This synchronization feature allows a reset of the counter after the reception or transmission of a message in buffer 0. Each CAN module is a fast CPU bus peripheral which allows single-cycle byte or word read/write access. The CPU controls the CAN module by programming the registers in the CAN register block. This includes initialization of the CAN baud rate, logic level of the CAN pins, and enable/disable of the CAN module. A set of diagnostic features, such as loopback, listen only, and error identification, support development with the CAN module and provide a sophisticated error management tool. Each CAN module implements the following features: CAN specification 2.0B -- Standard data and remote frames -- Extended data and remote frames -- 0 to 8 bytes data length -- Programmable bit rate up to 1 Mbit/s 15 message buffers, each configurable as receive or transmit buffers -- Message buffers are 16-bit wide dual-port RAM -- One buffer may be used as a BASIC-CAN path Remote Frame support -- Automatic transmission after reception of a Remote Transmission Request (RTR) -- Auto receive after transmission of a RTR Acceptance filtering www.national.com 82 -- Two filtering capabilities: global acceptance mask and individual buffer identifiers -- One of the buffers uses an independent acceptance filtering procedure Programmable transmit priority Interrupt capability -- One interrupt vector for all message buffers (receive/ transmit/error) -- Each interrupt source can be enabled/disabled 16-bit counter with time stamp capability on successful reception or transmission of a message Power Save capabilities with programmable Wake-Up over the CAN bus (alternate source for the Multi-Input Wake-Up module) Push-pull capability of the input/output pins Diagnostic functions -- Error identification -- Loopback and listen-only features for test and initialization purposes
17.1
FUNCTIONAL DESCRIPTION
As shown in Figure 16, each CAN module consists of three blocks: the CAN core, interface management, and a dualported RAM containing the message buffers. There are two dedicated device pins for each CAN interface, CANnTX as the transmit output and CANnRX as the receive input. The CAN core implements the basic CAN protocol features such as bit-stuffing, CRC calculation/checking, and error management. It controls the transceiver logic and creates error signals according to the bus rules. In addition, it converts the data stream from the CPU (parallel data) to the serial CAN bus data. The interface management block is divided into the register block and the interface management processor. The register block provides the CAN interface with control information from the CPU and provides the CPU with status information from the CAN module. Additionally, it generates the interrupt to the CPU. The interface management processor is a state machine executing the CPU's transmission and reception commands and controlling the data transfer between several message buffers and the RX/TX shift registers. 15 message buffers are memory mapped into RAM to transmit and receive data through the CAN bus. Eight 16-bit registers belong to each buffer. One of the registers contains control and status information about the message buffer configuration and the current state of the buffer. The other registers are used for the message identifier, a maximum of up to eight data bytes, and the time stamp information. During the receive process, the incoming message will be stored in a hidden receive buffer until the message is valid. Then, the buffer contents will be copied into the first message buffer which accepts the ID of the received message.
CP3CN23
CANnTX
CANnRX Wake-Up
CTX
0
1
0
1
CRX
CAN CORE Transceiver Logic BTL, RX shift, TX shift, CRC
Bit Stream Processor
Error Management Logic
Control INTERFACE MANAGEMENT Interface Management Processor Acceptance Filtering
Status RAM
Data
Control
TX/RX Message Buffer 0
TX/RX Message Buffer 1 Interface Management Processor BTL CONFIG CAN PRESCALER CONTROL ACCEPTANCE MASKS
TX/RX Message Buffer 14
CPU BUS
DS281
Figure 16. CAN Block Diagram A CAN master module has the ability to set a specific bit called the "remote data request bit" (RTR) in a frame. Such This section provides a generic overview of the basic cona message is also called a "Remote Frame". It causes ancepts of the Controller Area Network (CAN). other module, either another master or a slave which acThe CAN protocol is a message-based protocol that allows cepts this remote frame, to transmit a data frame after the a total of 2032 (211 - 16) different messages in the standard remote frame has been completed. format and 512 million (229 - 16) different messages in the Additional modules can be added to an existing network extended frame format. without a configuration change. These modules can either Every CAN Frame is broadcast on the common bus. Each perform completely new functions requiring new data, or module receives every frame and filters out the frames process existing data to perform a new functionality. which are not required for the module's task. For example, As the CAN network is message oriented, a message can if a dashboard sends a request to switch on headlights, the be used as a variable which is automatically updated by the CAN module responsible for brake lights must not process controlling processor. If any module cannot process inforthis message. mation, it can send an overload frame.
17.2
BASIC CAN CONCEPTS
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The CAN protocol allows several transmitting modules to start a transmission at the same time as soon as they detect the bus is idle. During the start of transmission, every node monitors the bus line to detect whether its message is over-
written by a message with a higher priority. As soon as a transmitting module detects another module with a higher priority accessing the bus, it stops transmitting its own frame and switches to receive mode, as shown in Figure 17.
TxPIN MODULE A RxPIN
TxPIN MODULE B RxPIN
BUS LINE
RECESSIVE DOMINANT MODULE A SUSPENDS TRANSMISSION DS019
Figure 17.
CAN Message Arbitration
If a data or remote frame loses arbitration on the bus due to 17.2.2 CAN Frame Fields a higher-prioritized data or remote frame, or if it is destroyed Data and remote frames consist of the following bit fields: by an error frame, the transmitting module will automatically Start of Frame (SOF) retransmit it until the transmission is successful or software Arbitration Field has canceled the transmit request. Control Field If a transmitted message loses arbitration, the CAN module Data Field will restart transmission at the next possible time with the CRC Field message which has the highest internal transmit priority. ACK Field EOF Field 17.2.1 CAN Frame Types Communication via the CAN bus is basically established by means of four different frame types: Data Frame Remote Frame Error Frame Overload Frame Data and remote frames can be used in both standard and extended frame format. If no message is being transmitted, i.e., the bus is idle, the bus is kept at the "recessive" level. Remote and data frames are non-return to zero (NRZ) coded with bit-stuffing in every bit field, which holds computable information for the interface, i.e., start of frame, arbitration field, control field, data field (if present), and CRC field. Error and overload frames are also NRZ coded, but without bit-stuffing. After five consecutive bits of the same value (including inserted stuff bits), a stuff bit of the inverted value is inserted into the bit stream by the transmitter and deleted by the receiver. The following shows the stuffed and destuffed bit stream for consecutive ones and zeros.
Original or 10000011111 . . . unstuffed bit stream Stuffed bit stream (stuff bits in bold) 01111100000 . . .
Start of Frame (SOF) The Start of Frame (SOF) indicates the beginning of data and remote frames. It consists of a single "dominant" bit. A node is only allowed to start transmission when the bus is idle. All nodes have to synchronize to the leading edge (first edge after the bus was idle) caused by the SOF of the node which starts transmission first. Arbitration Field The Arbitration field consists of the identifier field and the RTR (Remote Transmission Request) bit. For extended frames there is also a SRR (Substitute Remote Request) and a IDE (ID Extension) bit inserted between ID18 and ID17 of the identifier field. The value of the RTR bit is "dominant" in a data frame and "recessive" in a remote frame. Control Field The Control field consists of six bits. For standard frames it starts with the ID Extension bit (IDE) and a reserved bit (RB0). For extended frames, the control field starts with two reserved bits (RB1, RB0). These bits are followed by the 4bit Data Length Code (DLC). The CAN receiver accepts all possible combinations of the reserved bits (RB1, RB0). The transmitter must be configured to send only zeros.
1000001111101 . . . 0111110000010 . . .
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Data Length Code (DLC) The DLC field indicates the number of bytes in the data field. It consists of four bits. The data field can be of length zero. The admissible number of data bytes for a data frame ranges from 0 to 8. Data Field
The remainder of this division is the CRC sequence transmitted over the bus. On the receiver side, the module divides all bit fields up to the CRC delimiter excluding stuff bits, and checks if the result is zero. This will then be interpreted as a valid CRC. After the CRC sequence a single "recessive" bit is transmitted as the CRC delimiter.
ACK Field The Data field consists of the data to be transferred within a data frame. It can contain 0 to 8 bytes. A remote frame has The ACK field is two bits long and contains the ACK slot and the ACK delimiter. The ACK slot is filled with a "recessive" no data field. bit by the transmitter. This bit is overwritten with a "domiCyclic Redundancy Check (CRC) nant" bit by every receiver that has received a correct CRC The CRC field consists of the CRC sequence followed by sequence. The second bit of the ACK field is a "recessive" the CRC delimiter. The CRC sequence is derived by the bit called the acknowledge delimiter. transmitter from the modulo 2 division of the preceding bit fields, starting with the SOF up to the end of the data field, excluding stuff-bits, by the generator polynomial: x15 + x14 + x10 + x8 + x7 + x4 + x3 + 1 The End of Frame field closes a data and a remote frame. It consists of seven "recessive" bits. 17.2.3 CAN Frame Formats
Data Frame The structure of a standard data frame is shown in Figure 18. The structure of an extended data frame is shown in Figure 19.
STANDARD DATA FRAME (number of bits = 44 + 8N) 8N (0 < N < 8)
START OF FRAME ID 10
16 CRC Field 8 15 CRC
Arbitration Field 11
Control Field 4
ID0 RTR IDE RB0 DLC3 DLC
Data Field 8
CRC DEL ACKNOWLEDGEMENT ACK DEL
END OF FRAME
d IDENTIFIER 10 ... 0
ddd
r
rrrrrrrr
DATA LENGTH CODE Bit Stuffing
Note: d = dominant r = recessive
DS020
Figure 18.
Standard Data Frame
EXTENDED DATA FRAME (number of bits = 64 + 8N) 8N (0 < N < 0)
START OF FRAME ID 28
16 CRC Field
CRC DEL SCK ACK DEL
Arbitration Field 11
ID18 SRR IDE ID17
Control Field 18
ID0 RTR RB1 RB0 DLC3
Data Field 8 8
END OF FRAME
4
DLC
15 CRC
d IDENTIFIER 28 ... 18
rr
ddd
r
rrrrrrrr
IDENTIFIER 17 ... 0
DATA LENGTH CODE
Bit Stuffing Note: d = dominant r = recessive DS021
Figure 19.
Extended Data Frame
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A CAN data frame consists of the following fields: Start of Frame (SOF) Arbitration Field + Extended Arbitration Control Field Data Field Cyclic Redundancy Check Field (CRC)
Acknowledgment Field (ACK) End of Frame (EOF) Remote Frame Figure 20 shows the structure of a standard remote frame. Figure 21 shows the structure of an extended remote frame.
STANDARD REMOTE FRAME (number of bits = 44) 16 START OF FRAME ID 10 Arbitration Field 11 ID0 RTR IDE RB0 DLC3 Control Field 4 DLC0 CRC Field 15 CRC CRC DEL ACKNOWLEDGEMENT ACK DEL r
END OF FRAME
d IDENTIFIER 10 ... 0 Note: d = dominant r = recessive
ID3
ddd
rrrrrrrr
DATA LENGTH CODE DS022
Figure 20.
Standard Remote Frame
EXTENDED REMOTE FRAME (number of bits = 64) 16 START OF FRAME ID 28 Arbitration Field 11 ID18 SRR IDE ID17 18 ID0 RTR RB1 RB0 DLC3 Control Field 4 DLC0 CRC Field CRC DEL SCK ACK DEL r rrrrrrrr 15 CRC END OF FRAME
d IDENTIFIER 28 ... 18 Note: d = dominant r = recessive
rr
rdd
IDENTIFIER 17 ... 0
DATA LENGTH CODE
DS023
Figure 21. Extended Remote Frame A remote frame is comprised of the following fields, which is the same as a data frame (see CAN Frame Fields on page 84) except for the data field, which is not present. Start of Frame (SOF) Arbitration Field + Extended Arbitration Control Field Cyclic Redundancy Check Field (CRC) Acknowledgment field (ACK) End of Frame (EOF) Note that the DLC must have the same value as the corresponding data frame to prevent contention on the bus. The RTR bit is "recessive".
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Error Frame
at the bit following the acknowledge delimiter, unless an erAs shown in Figure 22, the Error Frame consists of the error ror flag for a previous error condition has already been startflag and the error delimiter bit fields. The error flag field is ed. built up from the various error flags of the different nodes. If a device is in the error active state, it can send a "domiTherefore, its length may vary from a minimum of six bits up nant" error flag, while a error passive device is only allowed to a maximum of twelve bits depending on when a module to transmit "recessive" error flags. This is done to prevent has detected the error. Whenever a bit error, stuff error, form the CAN bus from getting stuck due to a local defect. For the error, or acknowledgment error is detected by a node, the various CAN device states, please refer to Error Types on node starts transmission of an error flag at the next bit. If a page 88. CRC error is detected, transmission of the error flag starts
ERROR FRAME
6 ERROR FLAG
<6 ECHO ERROR FLAG
8 ERROR DELIMITER
DATA FRAME OR REMOVE FRAME
INTER-FRAME OR OVERLOAD FRAME
ddddddd Note: d = dominant r = recessive
dd
r
r
r
r
r
r
r
rd
An error frame can start anywhere within a frame
DS024
Figure 22. Error Frame Overload Frame As shown in Figure 23, an overload frame consists of the overload flag and the overload delimiter bit fields. The bit fields have the same length as the error frame field: six bits for the overload flag and eight bits for the delimiter. The overload frame can only be sent after the end of frame (EOF) field and in this way destroys the fixed form of the intermission field. As a result, all other nodes also detect an overload condition and start the transmission of an overload flag. After an overload flag has been transmitted, the overload frame is closed by the overload delimiter. Note: The CAN module never initiates an overload frame due to its inability to process an incoming message. However, it is able to recognize and respond to overload frames initiated by other devices.
OVERLOAD FRAME
6 END OF FRAME OR ERROR DELIMITER OR OVERLOAD DELIMITER OVERLOAD FLAG
8 OVERLOAD DELIMITER
INTER-FRAME SPACE OR ERROR FRAME
Note: d = dominant r = recessive
ddddddd
r
r
r
r
r
r
r
r DS025
An overload frame can only start at the end of a frame
Figure 23. Overload Frame Interframe Space Data and remote frames are separated from every preceding frame (data, remote, error and overload frames) by the interframe space (see Figure 24). Error and overload frames are not preceded by an interframe space; they can be transmitted as soon as the condition occurs. The interframe space consists of a minimum of three bit fields depending on the error state of the node.
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INTERFRAME SPACE 3 INT ANY FRAME
SUSPEND TRANSMIT
Bus Idle
START OF FRAME r rd
8
DATA FRAME OR REMOTE FRAME
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
INT = Intermission Suspend Transmission is only for error passive nodes.
Note: d = dominant r = recessive DS026
Figure 24. Interframe Space 17.2.4 Bit Error A CAN device which is currently transmitting also monitors the bus. If the monitored bit value is different from the transmitted bit value, a bit error is detected. However, the reception of a "dominant" bit instead of a "recessive" bit during the transmission of a passive error flag, during the stuffed bit stream of the arbitration field, or during the acknowledge slot is not interpreted as a bit error. Stuff Error Error Types a receiver, a "dominant" bit during the last bit of End of Frame does not constitute a frame error. Bit CRC Error A CRC error is detected if the remainder from the CRC calculation of a received CRC polynomial is non-zero. Acknowledgment Error An acknowledgment error is detected whenever a transmitting node does not get an acknowledgment from any other node (i.e., when the transmitter does not receive a "dominant" bit during the ACK frame).
A stuff error is detected if 6 consecutive bits occur without a Error States state change in a message field encoded with bit stuffing. The device can be in one of five states with respect to error Form Error handling (see Figure 25). A form error is detected, if a fixed frame bit (e.g., CRC delimiter, ACK delimiter) does not have the specified value. For
External Reset or Enable CR16CAN
SYNC
11 consecutive 'recessive" bits received (TEC OR REC) > 95 ERROR ACTIVE ERROR WARNING (TEC OR REC) > 127 ERROR PASSIVE TEC > 255 128 occurrences of 11 consecutive 'recessive" bits
(TEC AND REC) < 96
(TEC AND REC) < 128
BUS OFF
DS027
Figure 25. Synchronize
Bus States
the bus communication. This state must also be entered after waking-up the device using the Multi-Input Wake-Up feaOnce the CAN module is enabled, it waits for 11 consecutive recessive bits to synchronize with the bus. After that, the ture. See System Start-Up and Multi-Input Wake-Up on CAN module becomes error active and can participate in page 113.
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Error Active
when the transmit error counter is greater than 255. A bus An error active unit can participate in bus communication off device will become error active again after monitoring 128 x 11 "recessive" bits (including bus idle) on the bus. and may send an active ("dominant") error flag. When the device goes from "bus off" to "error active", both Error Warning error counters will have a value of 0. The Error Warning state is a sub-state of Error Active to indicate a heavily disturbed bus. The CAN module behaves as in Error Active mode. The device is reset into the Error Active mode if the value of both counters is less than 96. 17.2.5 Error Counters
There are multiple mechanisms in the CAN protocol to detect errors and inhibit erroneous modules from disabling all bus activities. Each CAN module includes two error Error Passive counters to perform error management. The receive error An error passive unit can participate in bus communication. counter (REC) and the transmit error counter (TEC) are 8However, if the unit detects an error it is not allowed to send bits wide, located in the 16-bit wide CANEC register. The an active error flag. The unit sends only a passive ("reces- counters are modified by the CAN module according to the sive") error flag. A device is error passive when the transmit rules listed in Table 35. This table provides an overview of error counter or the receive error counter is greater than the CAN error conditions and the behavior of the CAN mod127. A device becoming error passive will send an active er- ule; for a detailed description of the error management and ror flag. An error passive device becomes error active again fault confinement rules, refer to the CAN Specification 2.0B. when both transmit and receive error counter are less than If the MSB (bit 7) of the REC is set, the node is error passive 128. and the REC will not increment any further. Bus Off A unit that is bus off has the output drivers disabled, i.e., it does not participate in any bus activity. A device is bus off The Error counters can be read by application software as described under CAN Error Counter Register (CANECn) on page 112.
Table 35 Error Counter Handling Condition Receive Error Counter Conditions A receiver detects a bit error during sending an active error flag. A receiver detects a "dominant" bit as the first bit after sending an error flag After detecting the 14th consecutive "dominant" bit following an active error flag or overload flag, or after detecting the 8th consecutive "dominant" bit following a passive error flag. After each sequence of additional 8 consecutive "dominant" bits. Any other error condition (stuff, frame, CRC, ACK) A valid reception or transmission Transmit Error Counter Conditions A transmitter detects a bit error while sending an active error flag After detecting the 14th consecutive "dominant" bit following an active error flag or overload flag or after detecting the 8th consecutive "dominant" bit following a passive error flag. After each sequence of additional 8 consecutive `dominant' bits. Any other error condition (stuff, frame, CRC, ACK) A valid reception or transmission Special error handling for the TEC counter is performed in the following situations: A stuff error occurs during arbitration, when a transmitted "recessive" stuff bit is received as a "dominant" bit. This does not lead to an increment of the TEC. An ACK-error occurs in an error passive device and no "dominant" bits are detected while sending the passive error flag. This does not lead to an increment of the TEC. Increment by 8 Increment by 8 Increment by 8 Decrement by 1 unless counter is already 0 If only one device is on the bus and this device transmits a message, it will get no acknowledgment. This will be detected as an error and the message will be repeated. When the device goes "error passive" and detects an acknowledge error, the TEC counter is not incremented. Therefore the device will not go from "error passive" to the "bus off" state due to such a condition. Increment by 8 Increment by 8 Increment by 8 Increment by 1 Decrement by 1 unless counter is already 0 Action
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17.2.6
Bit Time Logic
CAN Bit Time The number of time quanta in a CAN bit (CAN Bit Time) ranges between 4 and 25. The sample point is positioned between TSEG1 and TSEG2 and the transmission point is positioned at the end of TSEG2.
In the Bit Time Logic (BTL), the CAN bus speed and the Synchronization Jump Width can be configured by software. The CAN module divides a nominal bit time into three time segments: synchronization segment, time segment 1 (TSEG1), and time segment 2 (TSEG2). Figure 26 shows the various elements of a CAN bit time.
INTERNAL TIME QUANTA CLOCK ONE TIME QUANTUM 4 to 25 TIme Quanta
A 16 TIme Quanta
TIME SEGMENT 1 (TSEG1) 2 to 16 Time Quanta
TIME SEGMENT 1 (TSEG1) 1 to 8 Time Quanta
A = synchronization segment (Sync)
SAMPLE POINT
TRANSMISSION POINT DS028
Figure 26. TSEG1 includes the propagation segment and the phase segment 1 as specified in the CAN specification 2.0B. The length of the time segment 1 in time quanta (tq) is defined by the TSEG1[3:0] bits. TSEG2 represents the phase segment 2 as specified in the CAN specification 2.0B. The length of time segment 2 in time quanta (tq) is defined by the TSEG2[3:0] bits. The Synchronization Jump Width (SJW) defines the maximum number of time quanta (tq) by which a received CAN bit can be shortened or lengthened in order to achieve resynchronization on "recessive" to "dominant" data transitions on the bus. In the CAN implementation, the SJW must be configured less or equal to TSEG1 or TSEG2, whichever is smaller. Synchronization A CAN device expects the transition of the data signal to be within the synchronization segment of each CAN bit time. This segment has the fixed length of one time quantum. However, two CAN nodes never operate at exactly the same clock rate, and the bus signal may deviate from the ideal waveform due to the physical conditions of the network (bus length and load). To compensate for the various delays within a network, the sample point can be positioned by programming the length of TSEG1 and TSEG2 (see Figure 26). In addition, two types of synchronization are supported. The BTL logic compares the incoming edge of a CAN bit with the internal bit timing. The internal bit timing can be adapted by either hard or soft synchronization (re-synchronization). Hard synchronization is performed at the beginning of a new frame with the falling edge on the bus while the bus is idle. This is interpreted as the SOF. It restarts the internal logic. Soft synchronization is performed during the reception of a bit stream to lengthen or shorten the internal bit time. Dewww.national.com
Bit Timing pending on the phase error (e), TSEG1 may be increased or TSEG2 may be decreased by a specific value, the resynchronization jump width (SJW). The phase error is given by the deviation of the edge to the SYNC segment, measured in CAN clocks. The value of the phase error is defined as: e = 0, if the edge occurs within the SYNC segment e > 0, if the edge occurs within TSEG1 e < 0, if the edge occurs within TSEG2 of the previous bit Resynchronization is performed according to the following rules: If the magnitude of e is less then or equal to the programmed value of SJW, resynchronization will have the same effect as hard synchronization. If e > SJW, TSEG1 will be lengthened by the value of the SJW (see Figure 27). If e < -SJW, TSEG2 will be shortened by the value SJW (see Figure 28).
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e Bus Signal
CAN Clock PREVIOUS BIT
A
TSEG1 "NORMAL" BIT TIME
TSEG2
NEXT BIT
PREVIOUS BIT
A
TSEG1
SJW
TSEG2
NEXT BIT
BIT TIME LENGTHENED BY SJW DS029
Figure 27.
Resynchronization (e > SJW)
e
Bus Signal
CAN Clock PREVIOUS BIT
A
TSEG1 "NORMAL" BIT TIME
TSEG2
PREVIOUS BIT
A
TSEG1 BIT TIME SHORTENED BY SJW
TSEG2
NEXT BIT
DS030
Figure 28. 17.2.7 Clock Generator
Resynchronization (e < -SJW) PSC = PSC[5:0] + 2 TSEG1 = TSEG1[3:0] + 1 TSEG2 = TSEG2[2:0] + 1
The CAN prescaler (PSC) is shown is Figure 29. It divides the CKI input clock by the value defined in the CTIM register. The resulting clock is called time quanta clock and defines the length of one time quantum (tq). Please refer to CAN Timing Register (CTIM) on page 108 for a detailed description of the CTIM register. Note: PSC is the value of the clock prescaler. TSEG1 and TSEG2 are the length of time segment 1 and 2 in time quanta. The resulting bus clock can be calculated by the equation: CKI busclock = -----------------------------------------------------------------------------------( PSC )x ( 1 + TSEG1 + TSEG2 )
CKI
/ PSC
/ (1+TSEG1+TSEG2)
Internal Time Quanta Clock (1/tq)
Bit Rate
DS031
Figure 29. CAN Prescaler
17.3
MESSAGE TRANSFER
The CAN module has access to 15 independent message buffers, which are memory mapped in RAM. Each message buffer consists of 8 different 16-bit RAM locations and can The values of PSC, TSEG1, and TSEG2 are specified by be individually configured as a receive message buffer or as the contents of the registers PSC, TSEG1, and TSEG2 as a transmit message buffer. follows: A dedicated acceptance filtering procedure enables software to configure each buffer to receive only a single message ID or a group of messages. One buffer uses an
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independent filtering procedure, which provides the possibility to establish a BASIC-CAN path. For reception of data frame or remote frames, the CAN module follows a "receive on first match" rule which means that a given message is only received by one buffer: the first one which matches the received message ID.
This provides the capability to accept only a single ID for each buffer or to accept a group of IDs. The following two examples illustrate the difference. Example 1: Acceptance of a Single Identifier
If the global mask is loaded with 00h, the acceptance filtering of an incoming message is only determined by the indiThe transmission of a frame can be initiated by software vidual buffer ID. This means that only one message ID is writing to the transmit status and priority register. An alter- accepted for each buffer. nate way to schedule a transmission is the automatic answer to remote frames. In the latter case, the CAN module GMASK1 GMASK2 00000000 00000000 00000000 00000 will schedule every buffer for transmission to respond to remote frames with a given identifier if the acceptance mask matches. This implies that a single remote frame is able to BUFFER_ID1 BUFFER_ID2 10101010 10101010 10101010 10101 poll multiple matching buffers configured to respond to the triggering remote transmission request.
17.4
ACCEPTANCE FILTERING
10101010
Accepted ID 10101010 10101010 10101 DS033
Two 32-bit masks are used to filter unwanted messages from the CAN bus: GMASK and BMASK. Figure 30 shows the mask and the buffers controlled by the masks.
Buffer 0 BUFFER_ID
Figure 31.
Acceptance of a Single Identifier
Example 2: Reception of an Identifier Group Set bits in the global mask register change the corresponding bit status within the buffer ID to "don't care" (X). Messages which match the non-"don't care" bits (the bits corresponding to clear bits in the global mask register) are accepted.
GMASK1 GMASK2 Buffer 13 BUFFER_ID
GMASK1 00000000 11111111
GMASK2 00000000 00000
BUFFER_ID1 10101010 10101010 Buffer 14 BMASK1 BMASK2 BUFFER_ID 10101010
BUFFER_ID2 10101010 10101
Accepted ID Group XXXXXXXX 10101010 10101 DS034
DS032
Figure 32. Acceptance of a Group of Identifiers Figure 30. Acceptance Filtering A separate filtering path is used for buffer 14. For this buffer, acceptance filtering is established by the buffer ID in conjunction with the basic filtering mask. This basic mask uses the same method as the global mask (set bits correspond to "don't care" bits in the buffer ID). Therefore, the basic mask allows a large number of infrequent messages to be received by this buffer. Note: If the BMASK register is equal to the GMASK register, the buffer 14 can be used the same way as the buffers 0 to 13. The buffers 0 to 13 are scanned prior to buffer 14. Subsequently, the buffer 14 will not be checked for a matching ID when one of the buffers 0 to 13 has already received an object.
Acceptance filtering of the incoming messages for the buffers 0...13 is performed by means of a global filtering mask (GMASK) and by the buffer ID of each buffer. Acceptance filtering of incoming messages for buffer 14 is performed by a separate filtering mask (BMASK) and by the buffer ID of that buffer. Once a received object is waiting in the hidden buffer to be copied into a buffer, the CAN module scans all buffers configured as receive buffers for a matching filtering mask. The buffers 0 to 13 are checked in ascending order beginning with buffer 0. The contents of the hidden buffer are copied into the first buffer with a matching filtering mask.
Bits holding a 1 in the global filtering mask (GMASK) can be represented as a "don't care" of the associated bit of each By setting the BUFFLOCK bit in the configuration register, buffer identifier, regardless of whether the buffer identifier bit the receiving buffer is automatically locked after reception of is 1 or 0. one valid frame. The buffer will be unlocked again after the CPU has read the data and has written RX_READY in the www.national.com 92
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buffer status field. With this lock function, software has the capability to save several messages with the same identifier or same identifier group into more than one buffer. For example, a buffer with the second highest priority will receive a message if the buffer with the highest priority has already received a message and is now locked (provided that both buffers use the same acceptance filtering mask).
As shown in Figure 33, several messages with the same ID are received while BUFFLOCK is enabled. The filtering mask of the buffers 0, 1, 13, and 14 is set to accept this message. The first incoming frame will be received by buffer 0. Because buffer 0 is now locked, the next frame will be received by buffer 1, and so on. If all matching receive buffers are full and locked, a further incoming message will not be received by any buffer.
Received ID GMASK
01010 00000
10101010 11111111
10101010 00000000
10101010 00000000
BUFFER0_ID BUFFER1_ID BUFFER13_ID
01010 01010 01010
XXXXXXXX XXXXXXXX XXXXXXXX
10101010 10101010 10101010
10101010 10101010 10101010
Saved when buffer is empty Saved when buffer is empty Saved when buffer is empty
BMASK BUFFER14_ID
00000 01010
11111111 XXXXXXXX
00000000 10101010
00000000 10101010 Saved when buffer is empty DS035
Figure 33.
Message Storage with BUFFLOCK Enabled Note: The hidden receive buffer must not be accessed by the CPU.
Buffer 0 BUFFER_ID
17.5
RECEIVE STRUCTURE
All received frames are initially buffered in a hidden receive buffer until the frame is valid. (The validation point for a received message is the next-to-last bit of the EOF.) The received identifier is then compared to every buffer ID together with the respective mask and the status. As soon as the validation point is reached, the whole contents of the hidden buffer are copied into the matching message buffer as shown in Figure 34.
Buffer 13 CR16CAN Hidden Receive Buffer BUFFER_ID
Buffer 14 BUFFER_ID
DS036
Figure 34. Receive Buffer The following section gives an overview of the reception of the different types of frames. The received data frame is stored in the first matching receive buffer beginning with buffer 0. For example, if the message is accepted by buffer 5, then at the time the message will be copied, the RX request is cleared and the CAN module will not try to match the frame to any subsequent buffer.
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All contents of the hidden receive buffer are always copied into the respective receive buffer. This includes the received message ID as well as the received Data Length Code (DLC); therefore when some mask bits are set to don't care, the ID field will get the received message ID which could be different from the previous ID. The DLC of the receiving buffer will be updated by the DLC of the received frame. The DLC of the received message is not compared with the DLC already present in the CNSTAT register of the message buffer. This implies that the DLC code of the CNSTAT register indicates how may data bytes actually belong to the latest received message.
Data Frames. In the second method, a remote frame can trigger one or more message buffer to transmit a data frame upon reception. This procedure is described under To Answer Remote Frames on page 96. 17.5.1 Receive Timing
As soon as the CAN module receives a "dominant" bit on the CAN bus, the receive process is started. The received ID and data will be stored in the hidden receive buffer if the global or basic acceptance filtering matches. After the reception of the data, CAN module tries to match the buffer ID of buffer 0...14. The data will be copied into the buffer after the reception of the 6th EOF bit as a message is valid at this The remote frames are handled by the CAN interface in two time. The copy process of every frame, regardless of the different ways. In the first method, remote frames can be relength, takes at least 17 CKI cycles (see also CPU Access ceived like data frames by configuring the buffer to be to CAN Registers/Memory on page 100). Figure 35 shows RX_READY and setting the ID bits including the RTR bit. In the receive timing. that case, the same procedure applies as described for
BUS IDLE BUS
SOF 1 BIT
ARBITRATION FIELD + CONTROL 12/29 BIT + 6 BIT
DATA FIELD (IF PRESENT) n x 8 BIT
CRC FIELD 16 BIT
ACK FIELD 2 BIT
EOF 7 BIT
IFS 3 BIT
rx_start Copy to Buffer BUSY
DS037
Figure 35. Receive Timing To indicate that a frame is waiting in the hidden buffer, the BUSY bit (ST[0]) of the selected buffer is set during the copy procedure. The BUSY bit will be cleared by the CAN module immediately after the data bytes are copied into the buffer. After the copy process is finished, the CAN module changes the status field to RX_FULL. In turn, the CPU should change the status field to RX_READY when the data is processed. When a new object has been received by the same buffer, before the CPU changed the status to RX_READY, the CAN module will change the status to RX_OVERRUN to indicate that at least one frame has been overwritten by a new one. Table 36 summarizes the current status and the resulting update from the CAN module. Table 36 Writing to Buffer Status Code During RX_BUSY Current Status RX_READY RX_NOT_ACTIVE RX_FULL Resulting Status RX_FULL RX_NOT_ACTIVE RX_OVERRUN ister (CNSTAT) on page 101). The various receive buffer states are explained in RX Buffer States on page 95. 17.5.2 Receive Procedure
Software executes the following procedure to initialize a message buffer for the reception of a CAN message. 1. Configure the receive masks (GMASK or BMASK). 2. Configure the buffer ID. 3. Configure the message buffer status as RX_READY. To read the out of a received message, the CPU must execute the following steps (see Figure 36):
During the assertion of the BUSY bit, all writes to the receiving buffer are disabled with the exception of the status field. If the status is changed while the BUSY bit is asserted, the status is updated by the CAN module as shown in Table 36. The buffer states are indicated and controlled by the ST[3:0] bits in the CNSTAT register (see Buffer Status/Control Regwww.national.com 94
CP3CN23
Read buffer
2.
Read CNSTAT
3. 4. 5.
Yes
RX_READY?
No Yes RX_BUSYx?
6.
7.
No Interrupt Entry Point
RX_FULL state (see also Interrupts on page 98). In that case the procedure described below must be followed. Read the status to determine if a new message has overwritten the one originally received which triggered the interrupt. Write RX_READY into CNSTAT. Read the ID/data and object control (DLC/RTR) from the message buffer. Read the buffer status again and check it is not RX_BUSYx. If it is, repeat this step until RX_BUSYx has gone away. If the buffer status is RX_FULL or RX_OVERRUN, one or more messages were copied. In that case, start over with step 2. If status is still RX_READY (as set by the CPU at step 2), clear interrupt pending bit and exit.
RX_OVERRUN?
(optional, for information)
When the BUFFLOCK function is enabled (see BUFFLOCK on page 92), it is not necessary to check for new messages received during the read process from the buffer, as this buffer is locked after the reception of the first valid frame. A read from a locked receive buffer can be performed as shown in Figure 37.
Interrupt Entry Point
Write RX_READY
Read buffer (id/data/control)
Read buffer (id/data/control)
Read CNSTAT
Write RX_READY
RX_BUSYx?
Yes
Clear RX_PND
No
Exit Yes
RX_FULL or RX_OVERRUN? No Clear RX_PND
DS039
Figure 37. Buffer Read Routine (BUFFLOCK Enabled) For simplicity only the applicable interrupt routine is shown: 1. Read the ID/data and object control (DLC/RTR) from the message buffer. 2. Write RX_READY into CNSTAT. 3. Clear interrupt pending bit and exit. 17.5.3 RX Buffer States
Exit
DS038
Figure 36.
Buffer Read Routine (BUFFLOCK Disabled)
The first step is only applicable if polling is used to get the As shown in Figure 37, a receive procedure starts as soon status of the receive buffer. It can be deleted for an interrupt as software has set the buffer from the RX_NOT_ACTIVE state into the RX_READY state. The status section of CNdriven receive routine. STAT register is set from 0000b to 0010b. When a message 1. Read the status (CNSTAT) of the receive buffer. If the is received, the buffer will be RX_BUSYx during the copy status is RX_READY, no was the message received, so process from the hidden receive buffer into the message exit. If the status is RX_BUSY, the copy process from buffer. Afterwards this buffer is RX_FULL. The CPU can hidden receive buffer is not completed yet, so read CNthen read the buffer data and either reset the buffer status STAT again. to RX_READY or receive a new frame before the CPU reads the buffer. In the second case, the buffer state will automatIf a buffer is configured to RX_READY and its interrupt ically change to RX_OVERRUN to indicate that at least one is enabled, it will generate an interrupt as soon as the message was lost. During the copy process the buffer will buffer has received a message and entered the again be RX_BUSYx for a short time, but in this case the
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CNSTAT status section will be 0101b, as the buffer was RX_FULL (0100b) before. After finally reading the last received message, the CPU can reset the buffer to RX_READY.
tance filtering mask of one or more buffers, the buffer status will change to TX_ONCE_RTR, the contents of the buffer will be transmitted, and afterwards the CAN module will write TX_RTR in the status code register again.
If the CPU writes TX_ONCE_RTR into the buffer status, the contents of the buffer will be transmitted, and the successful To transmit a CAN message, software must configure the transmission the buffer goes into the "wait for Remote message buffer by changing the buffer status to Frame" condition TX_RTR. TX_NOT_ACTIVE. The buffer is configured for transmission if the ST[3] bit of the buffer status code (CNSTAT) is set. In 17.6.1 Transmit Scheduling TX_NOT_ACTIVE status, the buffer is ready to receive data After writing TX_ONCE into the buffer status, the transmisfrom the CPU. After receiving all transmission data (ID, data sion process begins and the BUSY bit is set. As soon as a bytes, DLC, and PRI), the CPU can start the transmission buffer gets the TX_BUSY status, the buffer is no longer acby writing TX_ONCE into the buffer status register. During cessible by the CPU except for the ST[3:1] bits of the CNthe transmission, the status of the buffer is TX_BUSYx. Af- STAT register. Starting with the beginning of the CRC field ter successful transmission, the CAN module will reset the of the current frame, the CAN module looks for another buffbuffer status to TX_NOT_ACTIVE. If the transmission pro- er transmit request and selects the buffer with the highest cess fails, the buffer condition will remain TX_BUSYx for re- priority for the next transmission by changing the buffer transmission until the frame was successfully transmitted or state from TX_ONCE to TX_BUSY. This transmit request the CPU has canceled the transmission request. can be canceled by the CPU or can be overwritten by anoth-
17.6
TRANSMIT STRUCTURE
er transmit request of a buffer with a higher priority as long as the transmission of the next frame has not yet started. This means that between the beginning of the CRC field of the current frame and the transmission start of the next frame, two buffers, the current buffer and the buffer scheduled for the next transmission, are in the BUSY status. To cancel the transmit request of the next frame, the CPU must change the buffer state to TX_NOT_ACTIVE. When the transmit request has been overwritten by another request of a higher priority buffer, the CAN module changes the buffer state from TX_BUSY to TX_ONCE. Therefore, the transmit To answer Remote Frames, the CPU writes TX_RTR in the request remains pending. Figure 38 further illustrates the buffer status register, which causes the buffer to wait for a transmit timing. remote frame. When a remote frame passes the accepTo Send a Remote Frame (Remote Transmission Request) to other CAN nodes, software sets the RTR bit of the message identifier (see Storage of Remote Messages on page 105) and changes the status of the message buffer to TX_ONCE. After this remote frame has been transmitted successfully, this message buffer will automatically enter the RX_READY state and is ready to receive the appropriate answer. Note that the mask bits RTR/XRTR need to be set to receive a data frame (RTR = 0) in a buffer which was configured to transmit a remote frame (RTR = 1).
BUS IDLE BUS
SOF 1 BIT
ARBITRATION FIELD + CONTROL 12/29 BIT + 6 BIT
DATA FIELD (IF PRESENT) n x 8 BIT
CRC FIELD 16 BIT
ACK FIELD 2 BIT
EOF 7 BIT
IFS 3 BIT
TX_BUSY current buffer CPU write TX_ONCE in buffer status TX_BUSY next buffer
Begin selection of next buffer if new tx_request
DS040
Figure 38.
Data Transmission 17.6.2 Transmit Priority
If the transmit process fails or the arbitration is lost, the transmission process will be stopped and will continue after the interrupting reception or the error signaling has finished (see Figure 38). In that case, a new buffer select follows and the TX process is executed again.
Note: The canceled message can be delayed by a TX request of a buffer with a higher priority. While TX_BUSY is high, software cannot change the contents of the message If more than one buffer is scheduled for transmission, the buffer object. In all cases, writing to the BUSY bit will be ig- priority is built by the message buffer number and the priornored. ity code in the CNSTAT register. The 8-bit value of the priorwww.national.com 96
The CAN module is able to generate a stream of scheduled messages without releasing the bus between two messages so that an optimized performance can be achieved. It will arbitrate for the bus immediately after sending the previous message and will only release the bus due to a lost arbitration.
CP3CN23
ity is combined by the 4-bit TXPRI value and the 4-bit buffer number (0...14) as shown below. The lowest resulting number results in the highest transmit priority. 7 TXPRI 4 3 BUFFER # 0
17.6.3
Transmit Procedure
The transmission of a CAN message must be executed as follows (see also Figure 39) 1. Configure the CNSTAT status field as TX_NOT_ACTIVE. If the status is TX_BUSY, a previous transmit request is still pending and software has no access to the data contents of the buffer. In that case, software may choose to wait until the buffer becomes available again as shown. Other options are to exit from the update routine until the buffer has been transmitted with an interrupt generated, or the transmission is aborted by an error. 2. Load buffer identifier and data registers. (For remote frames the RTR bit of the identifier needs to be set and loading data bytes can be omitted.) 3. Configure the CNSTAT status field to the desired value: -- TX_ONCE to trigger the transmission process of a single frame. -- TX_ONCE_RTR to trigger the transmission of a single data frame and then wait for a received remote frame to trigger consecutive data frames. -- TX_RTR waits for a remote frame to trigger the transmission of a data frame. Writing TX_ONCE or TX_ONCE_RTR in the CNSTAT status field will set the internal transmit request for the CAN module. If a buffer is configured as TX_RTR and a remote frame is received, the data contents of the addressed buffer will be transmitted automatically without further CPU activity.
Write_buffer
Table 37 shows the transmit priority configuration if the priority is TXPRI = 0 for all transmit buffers: Table 37 Transmit Priority (TXPRI = 0) TXPRI 0 0 : : 0 Buffer Number 0 1 : : 14 PRI 0 1 : : 14 : : Lowest TX Priority Highest
Table 38 shows the transmit priority configuration if TXPRI is different from the buffer number: Table 38 Transmit Priority (TXPRI not 0) TXPRI 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Buffer Number 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 PRI 224 209 194 179 164 149 134 TX Priority Lowest
Write TX_NOT_ACTIVE
TX_BUSYx? No
Yes
119
Write ID/data
104 89 74 59 44 29 14 Highest
Exit DS041 Write TX_ONCE or TX_ONCE_RTR or TX_RTR
Note: If two buffers have the same priority (PRI), the buffer with the lower buffer number will have the higher priority.
Figure 39. Buffer Write Routine
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17.6.4
If the CPU configures the message buffer to The transmission process can be started after software has TX_ONCE_RTR, it will transmit its data contents. During the loaded the buffer registers (data, ID, DLC, PRI) and set the transmission, the buffer state is 1111b as the CPU wrote buffer status from TX_NOT_ACTIVE to TX_ONCE, 1110b into the status section of the CNSTAT register. After the successful transmission, the buffer enters the TX_RTR TX_RTR, or TX_ONCE_RTR. state and waits for a remote frame. When it receives a reWhen the CPU writes TX_ONCE, the buffer will be mote frame, it will go back into the TX_ONCE_RTR state, TX_BUSY as soon as the CAN module has scheduled this transmit its data bytes, and return to TX_RTR. If the CPU buffer for the next transmission. After the frame could be writes 1010b into the buffer status section, it will only enter successfully transmitted, the buffer status will be automati- the TX_RTR state, but it will not send its data bytes before cally reset to TX_NOT_ACTIVE when a data frame was it waits for a remote frame. Figure 40 illustrates the possible transmitted or to RX_READY when a remote frame was transmit buffer states. transmitted.
TX Buffer States
TX_ONCE_RTR 1110
RTR received
CAN schedules TX TX request CPU writes 1110 TX_BUSY2 1111
transmit failed TX done
Transmit request cancelled CPU writes 1000
TX_RTR 1010
CPU writes 1010
TX_NOT_ACTIVE 1000
TX request CPU writes 1100
TX_ONCE 1100 CAN schedules TX TX request delayed by a TX request of higher priority message RX_READY 0010
TX done Transmit request cancelled CPU writes 1000
Remote transmission request sent - now wait to receive a data frame
TX_BUSY0 1101
transmit failed DS042
Figure 40. Transmit Buffer States
17.7
INTERRUPTS
The CAN module has one dedicated ICU interrupt vector for all interrupt conditions. In addition, the data frame receive event is an input to the MIWU (see Section 13.0). The interrupt process can be initiated from the following sources. CAN data transfer -- Reception of a valid data frame in the buffer. (Buffer state changes from RX_READY to RX_FULL or RX_OVERRUN.) -- Successful transmission of a data frame. (Buffer state changes from TX_ONCE to TX_NOT_ACTIVE or RX_READY.)
-- Successful response to a remote frame. (Buffer state changes from TX_ONCE_RTR to TX_RTR.) -- Transmit scheduling. (Buffer state changes from TX_RTR to TX_ONCE_RTR.) CAN error conditions -- Detection of an CAN error. (The CEIPND bit in the CIPND register will be set as well as the corresponding bits in the error diagnostic register CEDIAG.) The receive/transmit interrupt access to every message buffer can be individually enabled/disabled in the CIEN register. The pending flags of the message buffer are located in the CIPND register (read only) and can be cleared by resetting the flags in the CICLR registers.
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17.7.1
Highest Priority Interrupt Code
Table 39 Highest Priority Interrupt Code (ICEN=FFFF) CAN Interrupt Request IRQ IST3 IST2 IST1 IST0
To reduce the decoding time for the CIPND register, the buffer interrupt request with the highest priority is placed as interrupt status code into the IST[3:0] section of the CSTPND register.
Buffer 10 1 1 0 1 1 Each of the buffer interrupts as well as the error interrupt Buffer 11 1 1 1 0 0 can be individually enabled or disabled in the CAN Interrupt Buffer 12 1 1 1 0 1 Enable register (CIEN). As soon as an interrupt condition occurs, every interrupt request is indicated by a flag in the Buffer 13 1 1 1 1 0 CAN Interrupt Pending register (CIPND). When the interrupt Buffer 14 1 1 1 1 1 code logic for the present highest priority interrupt request is enabled, this interrupt will be translated into the IST3:0 bits of the CAN Status Pending register (CSTPND). An in- 17.7.2 Usage Hints terrupt request can be cleared by setting the corresponding The interrupt code IST3:0 can be used within the interrupt bit in the CAN Interrupt Clear register (CICLR). handler as a displacement to jump to the relevant subrouFigure 41 shows the CAN interrupt management. tine.
CIEN
CICLR Clear interrupt flags of every message buffer individually CIPND
The CAN Interrupt Code Enable (CICEN) register is used in the CAN interrupt handler if software is servicing all receive buffer interrupts first, followed by all transmit buffer interrupts. In this case, software can first enable only receive buffer interrupts to be coded, then scan and service all pending interrupt requests in the order of their priority. After processing all the receive interrupts, software changes the CICEN register to disable all receive buffers and enable all transmit buffers, then services all pending transmit buffer interrupt requests according to their priorities.
CICEN ICODE IRQ IST3 IST2 IST1 IST0 DS043
17.8
TIME STAMP COUNTER
Figure 41. Interrupt Management The highest priority interrupt source is translated into the bits IRQ and IST3:0 as shown in Table 39. Table 39 Highest Priority Interrupt Code (ICEN=FFFF) CAN Interrupt Request No Request Error Interrupt Buffer 0 Buffer 1 Buffer 2 Buffer 3 Buffer 4 Buffer 5 Buffer 6 Buffer 7 Buffer 8 Buffer 9
The CAN module features a free running 16-bit timer (CTMR) incrementing every bit time recognized on the CAN bus. The value of this timer during the ACK slot is captured into the TSTP register of a message buffer after a successful transmission or reception of a message. Figure 42 shows a simplified block diagram of the Time Stamp counter.
CAN bits on the bus ACK slot and buffer 0 active
+1 Reset
16-Bit counter
ACK slot
IRQ 0 1 1 1 1 1 1 1 1 1 1 1
IST3 0 0 0 0 0 0 0 0 0 1 1 1
IST2 0 0 0 0 0 1 1 1 1 0 0 0
IST1 0 0 0 1 1 0 0 1 1 0 0 1
IST0 0 0 1 0 1 0 1 0 1 0 1 0 Figure 42. Time Stamp Counter The timer can be synchronized over the CAN network by receiving or transmitting a message to or from buffer 0. In this case, the TSTP register of buffer 0 captures the current CTMR value during the ACK slot of a message (as above), and then the CTMR is reset to 0000b. Synchronization can be enabled or disabled using the CGCR.TSTPEN bit.
TSTP register DS044
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17.9
MEMORY ORGANIZATION
Each CAN module occupies 144 words in the memory address space. This space is organized as 15 banks of 8 All register descriptions within the next sections have the folwords per bank (plus one reserved bank) for the message lowing layout: buffers and 14 words (plus 2 reserved words) for control and status. 15 0 17.9.1 CPU Access to CAN Registers/Memory Bit/Field Names All memory locations occupied by the message buffers are shared by the CPU and CAN module (dual-ported RAM). The CAN module and the CPU normally have single-cycle access to this memory. However, if an access contention occurs, the access to the memory is blocked every cycle until the contention is resolved. This internal access arbitration is transparent to software. Both word and byte access to the buffer RAM are allowed. If a buffer is busy during the reception of an object (copy process from the hidden receive buffer) or is scheduled for transmission, the CPU has no write access to the data contents of the buffer. Write to the status/control byte and read access to the whole buffer is always enabled. All configuration and status registers can either be accessed by the CAN module or the CPU only. These registers proReset Value CPU Access (R = read only, W = write only, R/W = read/write)
vide single-cycle word and byte access without any potential wait state.
17.9.2
Message Buffer Organization
The message buffers are the communication interfaces between CAN and the CPU for the transmission and the reception of CAN frames. There are 15 message buffers located at fixed addresses in the RAM location. As shown in Table 40, each buffer consists of two words reserved for the identifiers, 4 words reserved for up to eight CAN data bytes, one word reserved for the time stamp, and one word for data length code, transmit priority code, and the buffer status codes.
Table 40 Message Buffer Map Address 0E F0XEh 0E F0XCh 0E F0XAh 0E F0X8h 0E F0X6h 0E F0X4h 0E F0X2h 0E F0X0h Buffer Register ID1 ID0 DATA0 DATA1 DATA2 DATA3 TSTP CNSTAT DLC Reserved Data1[7:0] Data3[7:0] Data5[7:0] Data7[7:0] TSTP[15:0] PRI ST 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 XI[17:15] RTR Data2[7:0] Data4[7:0] Data6[7:0] Data8[7:0] 0
XI[28:18]/ID[10:0] XI[14:0]
SRR IDE /RTR
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17.10
CAN CONTROLLER REGISTERS
Table 41 CAN Controller Registers Name CNSTAT Address See Table 40 0E F100h Description CAN Buffer Status/ Control Register CAN Global Configuration Register 0 CAN Timing Register 0 Global Mask Register 0 Global Mask Register 0 Basic Mask Register 0 Basic Mask Register 0 CAN Interrupt Enable Register 0 CAN Interrupt Pending Register 0 CAN Interrupt Clear Register 0 CAN Interrupt Code Enable Register 0 CAN Status Pending Register 0 CAN Error Counter Register 0 CAN Error Diagnostic Register 0 CAN Timer Register 0 CAN Global Configuration Register 1 CAN Timing Register 1 Global Mask Register 1 Global Mask Register 1 Basic Mask Register 1 Basic Mask Register 1
Table 41 CAN Controller Registers Name CIEN1 CIPND1 CICLR1 CICEN1 CSTPND1 CANEC1 CEDIAG1 CTMR1 Address 0E F30Ch 0E F30Eh 0E F310h 0E F312h 0E F314h 0E F316h 0E F318h 0E F31Ah Description CAN Interrupt Enable Register 1 CAN Interrupt Pending Register 1 CAN Interrupt Clear Register 1 CAN Interrupt Code Enable Register 1 CAN Status Pending Register 1 CAN Error Counter Register 1 CAN Error Diagnostic Register 1 CAN Timer Register 1
Table 41 lists the CAN registers.
CGCR0
CTIM0 GMSKX0 GMSKB0 BMSKX0 BMSKB0 CIEN0 CIPND0 CICLR0 CICEN0 CSTPND0 CANEC0 CEDIAG0 CTMR0 CGCR1
0E F102h 0E F104h 0E F106h 0E F108h 0E F10Ah 0E F10Ch 0E F10Eh 0E F110h 0E F112h 0E F114h 0E F116h 0E F118h 0E F11Ah 0E F300h
17.10.1 Buffer Status/Control Register (CNSTAT) The buffer status (ST), the buffer priority (PRI), and the data length code (DLC) are controlled by manipulating the contents of the Buffer Status/Control Register (CNSTAT). The CPU and CAN module have access to this register. 15 DLC 12 11 Reserved 0 R/W 87 PRI 43 ST 0
ST
The Buffer Status field contains the status information of the buffer as shown in Table 42. This field can be modified by the CAN module. The ST0 bits acts as a buffer busy indication. When the BUSY bit is set, any write access to the buffer is disabled with the exception of the lower byte of the CNSTAT register. The CAN module sets this bit if the buffer data is currently copied from the hidden buffer or if a message is scheduled for transmission or is currently transmitting. The CAN module always clears this bit on a status update.
CTIM1 GMSKX1 GMSKB1 BMSKX1 BMSKB1
0E F302h 0E F304h 0E F306h 0E F308h 0E F30Ah
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Table 42 Buffer Status Section of the CNSTAT Register ST3 (DIR) 0 0 0 0 0 0 0 0 1 1 1 ST2 0 0 0 0 1 1 1 1 0 0 1 ST1 0 0 1 1 0 0 1 1 0 0 0 ST0 (BUSY) 0 1 0 1 0 1 0 1 0 1 0 RX_NOT_ACTIVE Reserved for RX_BUSY. (This condition indicates that software wrote RX_NOT_ACTIVE to a buffer when the data copy process is still active.) RX_READY RX_BUSY0 (Indicates data is being copied for the first time RX_READY RX_BUSY0.) RX_FULL RX_BUSY1 (Indicates data is being copied for the second time RX_FULL RX_BUSY1.) RX_OVERRUN RX_BUSY2 (Indicates data is being copied for the third or subsequent times RX_OVERRUN RX_BUSY2.) TX_NOT_ACTIVE Reserved for TX_BUSY. (This state indicates that software wrote TX_NOT_ACTIVE to a transmit buffer which is scheduled for transmission or is currently transmitting.) TX_ONCE TX_BUSY0 (Indicates that a buffer is scheduled for transmission or is actively transmitting; it can be due to one of two cases: a message is pending for transmission or is currently transmitting, or an automated answer is pending for transmission or is currently transmitting.) TX_RTR (Automatic response to a remote frame.) Reserved for TX_BUSY1. (This condition does not occur.) TX_ONCE_RTR (Changes to TX_RTR after transmission.) TX_BUSY2 (Indicates that a buffer is scheduled for transmission or is actively transmitting; it can be due to one of two cases: a message is pending for transmission or is currently transmitting, or an automated answer is pending for transmission or is currently transmitting.) Buffer Status
1
1
0
1
1 1 1
0 0 1
1 1 1
0 1 0
1
1
1
1
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PRI
DLC
The Transmit Priority Code field holds the software-defined transmit priority code for the message buffer. The Data Length Code field determines the number of data bytes within a received/transmitted frame. For transmission, these bits need to be set according to the number of data bytes to be transmitted. For reception, these bits indicate the number of valid received data bytes available in the message buffer. Table 43 shows the possible bit combinations for DLC3:0 for data lengths from 0 to 8 bytes. Table 43 Data Length Coding DLC 0000 0001 0010 0011 0100 0101 0110 0111 1000 Number of Data Bytes 0 1 2 3 4 5 6 7 8
Note: The maximum number of data bytes received/transmitted is 8, even if the DLC field is set to a value greater than 8. Therefore, if the data length code is greater or equal to eight bytes, the DLC field is ignored. 17.10.2 Storage of Standard Messages During the processing of standard frames, the ExtendedIdentifier (IDE) bit is clear. The ID1[3:0] and ID0[15:0] bits are "don't care" bits. A standard frame with eight data bytes is shown in Table 44. IDE The Identifier Extension bit determines whether the message is a standard frame or an extended frame. 0 - Message is a standard frame using 11 identifier bits. 1 - Message is an extended frame. The Remote Transmission Request bit indicates whether the message is a data frame or a remote frame. 0 - Message is a data frame. 1 - Message is a remote frame. The ID field is used for the 11 standard frame identifier bits.
RTR
ID
Table 44 Standard Frame with 8 Data Bytes Address 0E F0XEh 0E F0XCh 0E F0XAh 0E F0X8h 0E F0X6h 0E F0X4h 0E F0X2h 0E F0X0h Buffer Register ID1 ID0 DATA0 DATA1 DATA2 DATA3 TSTP CNSTAT DLC Reserved Data1[7:0] Data3[7:0] Data5[7:0] Data7[7:0] TSTP[15:0] PRI ST 15 14 13 12 11 10 ID[10:0] Don't Care Data2[7:0] Data4[7:0] Data6[7:0] Data8[7:0] 9 8 7 6 5 4 3 2 1 0
RTR IDE
Don't Care
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17.10.3 Storage of Messages with Less Than 8 Data Bytes The data bytes that are not used for data transfer are "don't cares". If the object is transmitted, the data within these bytes will be ignored. If the object is received, the data within these bytes will be overwritten with invalid data.
17.10.4 Storage of Extended Messages If the IDE bit is set, the buffer handles extended frames. The storage of the extended ID follows the descriptions in Table 45. The SRR bit is at the bit position of the RTR bit for standard frame and needs to be transmitted as 1.
Table 45 Extended Messages with 8 Data Bytes Address 0E F0XEh 0E F0XCh 0E F0XAh 0E F0X8h 0E F0X6h 0E F0X4h 0E F0X2h 0E F0X0h Buffer Register ID1 ID0 DATA0 DATA1 DATA2 DATA3 TSTP CNSTAT DLC Reserved Data1[7:0] Data3[7:0] Data5[7:0] Data7[7:0] TSTP[15:0] PRI ST 15 14 13 12 11 10 ID[28:18] ID[14:0] Data2[7:0] Data4[7:0] Data6[7:0] Data8[7:0] 9 8 7 6 5 4 3 2 1 ID17:15] RTR 0
SRR IDE
SRR
IDE
RTR
ID
The Substitute Remote Request bit replaces the RTR bit used in standard frames at this bit position. The SRR bit needs to be set by software if the buffer is configured to transmit a message with an extended identifier. It will be received as monitored on the CAN bus. The Identifier Extension bit determines whether the message is a standard frame or an extended frame. 0 - Message is a standard frame using 11 identifier bits. 1 - Message is an extended frame. The Remote Transmission Request bit indicates whether the message is a data frame or a remote frame. 0 - Message is a data frame. 1 - Message is a remote frame. The ID field is used to build the 29-bit identifier of an extended frame.
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17.10.5 Storage of Remote Messages During remote frame transfer, the buffer registers DATA0- DATA3 are "don't cares". If a remote frame is transmitted, the contents of these registers are ignored. If a remote
frame is received, the contents of these registers will be overwritten with invalid data. The structure of a message buffer set up for a remote frame with extended identifier is shown in Table 46.
Table 46 Extended Remote Frame Address 0E F0XEh 0E F0XCh 0E F0XAh 0E F0X8h 0E F0X6h 0E F0X4h 0E F0X2h 0E F0X0h Buffer Register ID1 ID0 DATA0 DATA1 DATA2 DATA3 TSTP CNSTAT DLC Reserved TSTP PRI ST Don't Care 15 14 13 12 11 10 ID[28:18] ID[14:0] 9 8 7 6 5 4 3 2 1 ID17:15] RTR 0
SRR IDE
SRR
IDE
RTR
ID
The Substitute Remote Request bit replaces the RTR bit used in standard frames at this bit position. The SRR bit needs to be set by software. The Identifier Extension bit determines whether the message is a standard frame or an extended frame. 0 - Message is a standard frame using 11 identifier bits. 1 - Message is an extended frame. The Remote Transmission Request bit indicates whether the message is a data frame or a remote frame. 0 - Message is a data frame. 1 - Message is a remote frame. The ID field is used to build the 29-bit identifier of an extended frame. The ID[28:18] field is used for the 11 standard frame identifier bits.
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17.10.6 CAN Global Configuration Register (CGCRn) The CGCRn register is a 16-bit wide register used to: Enable/disable the CAN module. Configure the BUFFLOCK function for the message buffer 0..14. Enable/disable the time stamp synchronization. Set the logic levels of the CAN Input/Output pins, CANRX and CANTX. Choose the data storage direction (DDIR). Select the error interrupt type (EIT). Enable/disable diagnostic functions. 7 6 5 4 3 2 1 0
TSTPEN
DDIR
TST BUFF IGNACK LO DDIR CRX CTX CANEN PEN LOCK 0 R/W
15
12
11
10 0 R/W
9
8
Reserved
EIT DIAGEN INTERNAL LOOPBACK
The Time Sync Enable bit enables or disables the time stamp synchronization function of the CAN module. 0 - Time synchronization disabled. The Time Stamp counter value is not reset upon reception or transmission of a message to/ from buffer 0. 1 - Time synchronization enabled. The Time Stamp counter value is reset upon reception or transmission of a message to/from buffer 0. The Data Direction bit selects the direction the data bytes are transmitted and received. The CAN module transmits and receives the CAN Data1 byte first and the Data8 byte last (Data1, Data2,...,Data7, Data8). If the DDIR bit is clear, the data contents of a received message is stored with the first byte at the highest data address and the last data at the lowest data address (see Figure 43). The same applies for transmitted data. 0 - First byte at the highest address, subsequent bytes at lower addresses. 1 - First byte at the lowest address, subsequent bytes at higher addresses.
The CAN Enable bit enables/disables the CAN module. When the CAN module is disabled, all internal states and the TEC and REC counter registers are cleared. In addition the CAN module clock is disabled. All CAN module control registers and the contents of the object memory are left unchanged. Software must make sure that no message is pending for transmission before the CAN module is disabled. 0 - CAN module is disabled. 1 - CAN module is enabled. CTX The Control Transmit bit configures the logic level of the CAN transmit pin CANTX. 0 - Dominant state is 0; recessive state is 1. 1 - Dominant state is 1; recessive state is 0. CRX The Control Receive bit configures the logic level of the CAN receive pin CANRX. 0 - Dominant state is 0; recessive state is 1. 1 - Dominant state is 1; recessive state is 0. BUFFLOCK The Buffer Lock bit configures the buffer lock function. If this feature is enabled, a buffer will be locked upon a successful frame reception. The buffer will be unlocked again by writing RX_READY in the buffer status register, i.e., after reading data. 0 - Lock function is disabled for all buffers. 1 - Lock function is enabled for all buffers.
CANEN
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Sequence of Data Bytes on the Bus ID Data1 Data2 Data3 Data4 Data5 Data6 Data7 Data8 CRC
t Storage of Data Bytes in the Buffer Memory ADDR Offset 0A16 0816 0616 0416 Data Bytes Data1 Data3 Data5 Data7 Data2 Data4 Data6 Data8
DS045
Figure 43. Data Direction Bit Clear Setting the DDIR bit will cause the direction of the data storage to be reversed -- the last byte received is stored at the highest address and the first byte is stored at the lowest address, as shown in Figure 44.
Sequence of Data Bytes on the Bus ID Data1 Data2 Data3 Data4 Data5 Data6 Data7 Data8 CRC
t Storage of Data Bytes in the Buffer Memory ADDR Offset 0A16 0816 0616 0416 Data Bytes Data8 Data6 Data4 Data2 Data7 Data5 Data3 Data1 DS046
Figure 44. LO
Data Direction Bit Set IGNACK When the Ignore Acknowledge bit is set, the CAN module does not expect to receive a dominant ACK bit to indicate the validity of a transmitted message. It will not send an error frame when the transmitted frame is not acknowledged by any other CAN node. This feature can be used in conjunction with the LOOPBACK bit for stand-alone tests outside of a CAN network. 0 - Normal mode. 1 - The CAN module does not expect to receive a dominant ACK bit to indicate the validity of a transmitted message. When the Loopback bit is set, all messages sent by the CAN module can also be received by a CAN module buffer with a matching buffer ID. However, the CAN module does not acknowledge a message sent by itself. Therefore, the CAN module will send an error frame when no other device connected to the bus has acknowledged the message. 0 - No loopback. 1 - Loopback enabled. www.national.com
The Listen Only bit can be used to configure the CAN interface to behave only as a receiver. This means: * Cannot transmit any message. * Cannot send a dominant ACK bit. * When errors are detected on the bus, the CAN module will behave as in the error passive mode. Using this listen only function, the CAN interface can be adjusted for connecting to an operating network with unknown bus speed. 0 - Transmit/receive mode. 1 - Listen-only mode.
LOOPBACK
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INTERNAL
DIAGEN
EIT
If the Internal function is enabled, the CANTX and CANRX pins of the CAN module are internally connected to each other. This feature can be used in conjunction with the LOOPBACK mode. This means that the CAN module can receive its own sent messages without connecting an external transceiver chip to the CANTX and CANRX pins; it allows software to run real stand-alone tests without any peripheral devices. 0 - Normal mode. 1 - Internal mode. The Diagnostic Enable bit globally enables or disables the special diagnostic features of the CAN module. This includes the following functions: * LO (Listen Only). * IGNACK (Ignore Acknowledge). * LOOPBACK (Loopback). * INTERNAL (Internal Loopback). * Write access to hidden receive buffer. 0 - Normal mode. 1 - Diagnostic features enabled. The Error Interrupt Type bit configures when the Error Interrupt Pending Bit (CIPND.EIPND) is set and an error interrupt is generated if enabled by the Error Interrupt Enable (CIEN.EIEN). 0 - The EIPND bit is set on every error on the CAN bus. 1 - The EIPND bit is set only if the error state (CSTPND.NS) changes as a result of incrementing either the receive or transmit error counter.
17.10.7 CAN Timing Register (CTIM) The Can Timing Register (CTIM) defines the configuration of the Bit Time Logic (BTL). 15 PSC 9 8 7 0 R/W 6 TSEG1 3 2 TSEG2 0
SJW
PSC
The Prescaler Configuration field specifies the CAN prescaler. The settings are shown in Table 47 Table 47 CAN Prescaler Settings PSC6:0 000000 000001 000010 000011 000100 : 1111101 1111110 1111111 Prescaler 2 3 4 5 6 : 127 128 128
SJW
The Synchronization Jump Width field specifies the Synchronization Jump Width, which can be programmed between 1 and 4 time quanta (see Table 48). Table 48 SJW Settings SJW 00 01 10 11 Synchronization Jump Width (SJW) 1 time quantum 2 time quanta 3 time quanta 4 time quanta
Note: The settings of SJW must be configured to be smaller or equal to TSEG1 and TSEG2
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TSEG1
The Time Segment 1 field configures the length of the Time Segment 1 (TSEG1). It is not recommended to configure the time segment 1 to be smaller than 2 time quanta. (see Table 49). Table 49 Time Segment 1 Settings TSEG1[3:0] 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Length of Time (TSEG1) Not recommended 2 time quanta 3 time quanta 4 time quanta 5 time quanta 6 time quanta 7 time quanta 8 time quanta 9 time quanta 10 time quanta 11 time quanta 12 time quanta 13 time quanta 14 time quanta 15 time quanta 16 time quanta
17.10.8 Global Mask Register (GMSKBn/GMSKXn) The GMSKBn and GMSKXn registers allow software to globally mask, or "don't care" the incoming extended/standard identifier bits, RTR/XRTR and IDE. Throughout this document, the GMSKBn and GMSKXn 16-bit registers are referenced as a 32-bit register GMSK. The following are the bits for the GMSKBn register. 15 GM28:18 5 4 RTR 0 R/W 3 IDE 2 GM17:15 0
The following are the bits for the GMSKXn register. 15 GM14:0 0 R/W 1 0 XRTR
For all GMSKBn and GMSKXn register bits, the following applies: 0 - The incoming identifier bit must match the corresponding bit in the message buffer identifier register. 1 - Accept 1 or 0 ("don't care") in the incoming ID bit independent from the corresponding bit in the message buffer ID registers. The corresponding ID bit in the message buffer will be overwritten by the incoming identifier bits.
TSEG2
When an extended frame is received from the CAN bus, all GMSK bits GM28:0, IDE, RTR, and XRTR are used to mask The Time Segment 2 field specifies the num- the incoming message. In this case, the RTR bit in the ber of time quanta (tq) for phase segment 2 GMSK register corresponds to the SRR bit in the message. The XRTR bit in the GMSK register corresponds to the RTR (see Table 50). bit in the message. Table 50 Time Segment 2 Settings During the reception of standard frames only the GMSK bits TSEG2 000 001 010 011 100 101 110 111 Length of TSEG2 1 time quantum 2 time quanta 3 time quanta 4 time quanta 5 time quanta 6 time quanta 7 time quanta 8 time quanta GM[28:18], RTR, and IDE are used. In this case, the GM[28:18] bits in the GMSK register correspond to the ID[10:0] bits in the message. Global Mask GM[28:18] RTR Standard Frame Extended Frame ID[10:0] ID[28:18] RTR IDE GM[17:0] XRTR IDE Unused ID[17:0] RTR
SRR IDE
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17.10.9 Basic Mask Register (BMSKBn/BMSKXn)
17.10.10 CAN Interrupt Enable Register (CIENn)
The BMSKBn and BMSKXn registers allow masking the The CIENn register enables the transmit/receive interrupts buffer 14, or "don't care" the incoming extended/standard of the message buffers 0 through 14 as well as the CAN Eridentifier bits, RTR/XRTR, and IDE. Throughout this docu- ror Interrupt. ment, the two 16-bit registers BMSKBn and BMSKXn are referenced to as a 32-bit register BMSK. 15 14 0 The following are the bits for the BMSKB register. EIEN IEN 15 BM28:18 5 0 R/W EIEN The Error Interrupt Enable bit allows the CAN module to interrupt the CPU if any kind of CAN receive/transmit errors are detected. This causes any error status change in the error counter registers REC/TEC is able to generate an error interrupt. 0 - The error interrupt is disabled and no error interrupt will be generated. 1 - The error interrupt is enabled and a change in REC/TEC will cause an interrupt to be generated. The Buffer Interrupt Enable bits allow software to enable/disable the interrupt source for the corresponding message buffer. For example, IEN14 controls interrupts from buffer14, and IEN0 controls interrupts from buffer0. 0 - Buffer as interrupt source disabled. 1 - Buffer as interrupt source enabled. 4 RTR 3 IDE 2 BM17:15 0 0 R/W
The following are the bits for the BMSKX register. 15 BM14:0 0 R/W IEN For all BMSKBn and BMSKXn register bits the following applies: 1 0 XRTR
0 - The incoming identifier bit must match the corresponding bit in the message buffer identifier register. 1 - Accept 1 or 0 ("don't care") in the incoming ID bit independent from the corresponding bit in the message 17.10.11 CAN Interrupt Pending Register (CIPNDn) buffer ID registers. The corresponding ID bit in the message buffer will be overwritten by the incoming identifier The CIPNDn register indicates any CAN Receive/Transmit Interrupt Requests caused by the message buffers 0..14 bits. and CAN error occurrences. When an extended frame is received from the CAN bus, all BMSK bits BM28:0, IDE, RTR, and XRTR are used to mask 15 14 0 the incoming message. In this case, the RTR bit in the BMSK register corresponds to the SRR bit in the message. The XRTR bit in the BMSK register corresponds to the RTR bit in the message. EIPND 0 R IPND
During the reception of standard frames, only the BMSK bits BM[28:18], RTR, and IDE are used. In this case, the BM[28:18] bits in the BMSK register correspond to the EIPND ID[10:0] bits in the message. Basic Mask Standard Frame Extended Frame BM28:18 ID10:0 ID28:18 RTR RTR IDE IDE BM17:0 XRTR Unused ID17:0 RTR IPND
SRR IDE
The Error Interrupt Pending field indicates the status change of TEC/REC and will execute an error interrupt if the EIEN bit is set. Software has the responsibility to clear the EIPND bit using the CICLRn register. 0 - CAN status is not changed. 1 - CAN status is changed. The Buffer Interrupt Pending bits are set by the CAN module following a successful transmission or reception of a message to or from the corresponding message buffer. For example, IPND14 corresponds to buffer14, and IPND0 corresponds to buffer0. 0 - No interrupt pending for the corresponding message buffer. 1 - Message buffer has generated an interrupt.
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17.10.12 CAN Interrupt Clear Register (CICLRn)
17.10.14 CAN Status Pending Register (CSTPNDn)
The CICLRn register bits individually clear CAN interrupt The CSTPNDn register holds the status of the CAN Node pending flags caused by the message buffers and from the and the Interrupt Code. Error Management Logic. Do not modify this register with instructions that access the register as a read-modify-write 15 87 5 4 3 0 operand, such as the bit manipulation instructions. Reserved NS IRQ IST 15 EICLR 0 W NS The CAN Node Status field indicates the status of the CAN node as shown in Table 51. Table 51 CAN Node Status NS 000 010 011 10X 11X IRQ/IST Node Status Not Active Error Active Error Warning Level Error Passive Bus Off 14 ICLR 0 0 R
EICLR
ICLR
The Error Interrupt Clear bit is used to clear the EIPND bit. 0 - The EIPND bit is unaffected by writing 0. 1 - The EIPND bit is cleared by writing 1. The Buffer Interrupt Clear bits are used to clear the IPND bits. 0 - The corresponding IPND bit is unaffected by writing 0. 0 - The corresponding IPND bit is cleared by writing 1.
17.10.13 CAN Interrupt Code Enable Register (CICENn) The CICENn register controls whether the interrupt pending flag in the CIPNDn register is translated into the Interrupt Code field of the CSTPNDn register. All interrupt requests, CAN error, and message buffer interrupts can be enabled/ disabled separately for the interrupt code indication field. 15 EICEN 0 R/W 14 ICEN 0
The IRQ bit and IST field indicate the interrupt source of the highest priority interrupt currently pending and enabled in the CICENn register. Table 52 shows the several interrupt codes when the encoding for all interrupt sources is enabled (CICEN = FFFFh). Table 52 Highest Priority Interrupt Code IRQ 0 1 IST3:0 0000 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 CAN Interrupt Request No interrupt request Error interrupt Buffer 0 Buffer 1 Buffer 2 Buffer 3 Buffer 4 Buffer 5 Buffer 6 Buffer 7 Buffer 8 Buffer 9 Buffer 10 Buffer 11 Buffer 12 Buffer 13 Buffer 14 www.national.com
EICEN
ICEN
The Error Interrupt Code Enable bit controls encoding for error interrupts. 0 - Error interrupt pending is not indicated in the interrupt code. 1 - Error interrupt pending is indicated in the interrupt code. The Buffer Interrupt Code Enable bits control encoding for message buffer interrupts. 0 - Message buffer interrupt pending is not indicated in the interrupt code. 1 - Message buffer interrupt pending is indicated in the interrupt code.
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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17.10.15 CAN Error Counter Register (CANECn) The CANECn register reports the values of the CAN Receive Error Counter and the CAN Transmit Error Counter. 15 REC 0 R EBID 8 7 TEC 0
Table 53 Error Field Identifier EFID3:0 1101 1110 1111 Field DLC DATA CRC
REC TEC
The CAN Receive Error Counter field reports the value of the receive error counter. The CAN Transmit Error Counter field reports the value of the transmit error counter.
The Error Bit Identifier field reports the bit position of the incorrect bit within the erroneous frame field. The bit number starts with the value equal to the respective frame field length minus one at the beginning of each field and is decremented with each CAN bit. Figure 45 shows an example on how the EBID is calculated.
17.10.16 CAN Error Diagnostic Register (CEDIAGn) The CEDIAGn register reports information about the last detected error. The CAN module identifies the field within the CAN frame format in which the error occurred, and it identifies the bit number of the erroneous bit within the frame field. The CPU bus master has read-only access to this register, and all bits are cleared on reset. 15 14 13 12 0 R 11 10 9 43 0 Figure 45. EBID Example For example, assume the EFID field shows 1110b and the EBID field shows 111001b. This means the faulty field was the data field. To calculate the bit position of the error, the DLC of the message needs to be known. For example, for a DLC of 8 data bytes, the bit counter starts with the value: (8 x 8) - 1 = 63; so when EBID[5:0] = 111001b = 57, then the bit number was 63 - 57 = 6. The Transmit Error bit indicates whether the CAN module was an active transmitter at the time the error occurred. 0 - The CAN module was a receiver at the time the error occurred. 1 - The CAN module was an active transmitter at the time the error occurred. The Stuff Error bit indicates whether the bit stuffing rule was violated at the time the error occurred. Note that certain bit fields do not use bit stuffing and therefore this bit may be ignored for those fields. 0 - No bit stuffing error. 1 - The bit stuffing rule was violated at the time the error occurred. The CRC Error bit indicates whether the CRC is invalid. This bit should only be checked if the EFID field shows the code of the ACK field. 0 - No CRC error occurred. 1 - CRC error occurred. The Monitor bit shows the bus value on the CANRX pin as sampled by the CAN module at the time of the error.
r r r r r r
Incorrect Bit Data Field DS047
Res. DRIVE MON CRC STUFF TXE EBID
EFID
EFID
The Error Field Identifier field identifies the frame field in which the last error occurred. The encoding of the frame fields is shown in Table 53. Table 53 Error Field Identifier EFID3:0 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 Field ERROR ERROR DEL ERROR ECHO BUS IDLE ACK EOF INTERMISSION SUSPEND TRANSMISSION SOF ARBITRATION IDE EXTENDED ARBITRATION R1/R0 MON CRC STUFF TXE
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DRIVE
The Drive bit shows the output value on the CANTX pin at the time of the error. Note that a receiver will not drive the bus except during ACK and during an active error flag.
17.11.1 External Connection The CAN module uses the CANnTX and CANnRX pins to connect to the physical layer of the CAN interface. They provide the functionality described in Table 54. Table 54 External CAN Pins Signal Name CANnTX Type Output Input Description Transmit data to the CAN bus Receive data from the CAN bus
17.10.17 CAN Timer Register (CTMRn) The CTMRn register reports the current value of the Time Stamp Counter as described in Section 17.8. 15 CTMR15:0 0 R 0
CANnRX
The logic levels are configurable by the CTX and CRX bits of the Global Configuration Register CGCRn (see "CAN Global Configuration Register (CGCRn)" on page 106). 17.11.2 Transceiver Connection
The CTMRn register is a free running 16-bit counter. It contains the number of CAN bits recognized by the CAN module since the register has been cleared. The counter starts to increment from the value 0000b after a hardware reset. If the Timer Stamp Enable bit (TSTPEN) in the CGCRn register is set, the counter will also be cleared on a message transfer of the message buffer 0. The contents of CTMR are captured into the Time Stamp register of the message buffer after successfully sending or receiving a frame, as described in "Time Stamp Counter" on page 99.
An external transceiver chip must be connected between the CAN block and the bus. It establishes a bus connection in differential mode and provides the driver and protection requirements. Figure 46 shows a possible ISO-High-Speed configuration.
120 Termination
CPU Bus
CAN bus signals
17.11
SYSTEM START-UP AND MULTI-INPUT WAKE-UP
To other modules CR16CAN Transceiver Chip 5 REF 4 RX 1 TX RS 8 VCC 7 BUS_H 6 BUS_L GND 2 3 VCC
After system start-up, all CAN-related registers are in their reset state. The CAN module can be enabled after all configuration registers are set to their desired value. The following initial settings must be made: Configure the CAN Timing register (CTIM). See "Bit Time Logic" on page 90. Configure every buffer to its function as receive/transmit. See "Buffer Status/Control Register (CNSTAT)" on page 101. Set the acceptance filtering masks. See "Acceptance Filtering" on page 92. Enable the CAN interface. See "CAN Global Configuration Register (CGCRn)" on page 106.
CANnRX CANnTX
120 DS282
Figure 46.
External Transceiver
Before disabling the CAN module, software must make sure 17.11.3 Timing Requirements that no transmission is still pending. Processing messages and updating message buffers reNote: Activity on the CAN bus can wake up the device from quire a certain number of clock cycles, as shown in a reduced-power mode by selecting the CANnRX pin as an Table 55. These requirements may lead to some restrictions input to the Multi-Input Wake-Up module. In this case, the regarding the Bit Time Logic settings and the overall CAN CAN module must not be disabled before entering the re- performance which are described below in more detail. Wait duced-power mode. Disabling the CAN module also dis- cycles need to be added to the cycle count for CPU access ables the CANnRX pin. As an alternative, the CANnRX pin to the object memory as described in CPU Access to CAN can be connected to any other input pin of the Multi-Input Registers/Memory on page 100. The number of occurrencWake-Up module. This input channel must then be config- es per frame is dependent on the number of matching idenured to trigger a wake-up event on a falling edge (if a domi- tifiers. nant bit is represented by a low level). In this case, the CAN module can be disabled before entering the reduced-power mode. After waking up, software must enable the CAN module again. All configuration and buffer registers still contain the same data they held before the reduced-power mode was entered.
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Table 55 CAN Module Internal Timing Task Copy hidden buffer to receive message buffer Update status from TX_RTR to TX_ONCE_RTR Schedule a message for transmission Cycle Count 17 3 2 Occurrence/ Frame 0-1 0-15 0-1
Table 56 gives examples for the minimum clock frequency in order to ensure proper functionality at various CAN bus speeds. Table 56 Minimum Clock Frequency Requirements Baud Rate 1 Mbit/sec 500 kbit/sec 250 kbit/sec Minimum Clock Frequency 15.25 MHz 7.625 MHz 3.81 MHz
The critical path derives from receiving a remote frame, which triggers the transmission of one or more data frames. There are a minimum of four bit times in-between two consecutive frames. These bit times start at the validation point of received frame (reception of 6th EOF bit) and end at the earliest possible transmission start of the next frame, which is after the third intermission bit at 100% burst bus load. These four bit times have to be set in perspective with the timing requirements of the CAN module. The minimum duration of the four CAN bit times is determined by the following Bit Time Logic settings: PSC = PSCmin = 2 TSEG1 = TSEG1min = 2 TSEG2 = TSEG2min = 1 Bit time = Sync + Time Segment 1 + Time Segment 2 = (1 + 2 + 1) tq = 4 tq = (4 tq x PSC) clock cycles = (4 tq x 2) clock cycles = 8 clock cycles
17.11.4 Bit Time Logic Calculation Examples The calculation of the CAN bus clocks using CKI = 16 MHz is shown in the following examples. The desired baud rate for both examples is 1 Mbit/s. Example 1 PSC = PSC[5:0] + 2 = 0 + 2 = 2 TSEG1 = TSEG1[3:0] + 1 = 3 + 1 = 4 TSEG2 = TSEG2[2:0] + 1 = 2 + 1 = 3 SJW = TSEG2 = 3 Sample point positioned at 62.5% of bit time Bit time = 125 ns x (1 + 4 + 3 3) = (1 0.375) s Bus Clock = 16 MHz / (2 x (1 + 4 + 3)) = 1 Mbit/s (nominal) Example 2 PSC = PSC[5:0] + 1 = 2 + 2 = 4 TSEG1 = TSEG1[3:0] + 1 = 1 + 1 = 2
For these minimum BTL settings, four CAN bit times take 32 TSEG2 = TSEG2[2:0] + 1 = 0 + 1 = 1 clock cycles. SJW = TSEG2 = 1 The following is an example that assumes typical case: Sample point positioned at 75% of bit time Bit time = 250 ns x (1 + 2 + 1 1) = (1 0.25) s Minimum BTL settings Bus Clock = 16 MHz / (2 x (1 + 4 + 3)) = 1Mbit/s (nominal) Reception and copy of a remote frame Update of one buffer from TX_RTR 17.11.5 Acceptance Filter Considerations Schedule of one buffer from transmit The CAN module provides two acceptance filter masks As outlined in Table 55, the copy process, update, and GMSK and BMSK, as described in "Acceptance Filtering" scheduling the next transmission gives a total of 17 + 3 + 2 on page 92, "Global Mask Register (GMSKBn/GMSKXn)" = 22 clock cycles. Therefore under these conditions there is on page 109, and "Basic Mask Register (BMSKBn/BMno timing restriction. SKXn)" on page 110. These masks allow filtering of up to 32 The following example assumes the worst case: bits of the message object, which includes the standard identifier, the extended identifier, and the frame control bits Minimum BTL settings RTR, SRR, and IDE. Reception and copy of a remote frame Update of the 14 remaining buffers from TX_RTR Schedule of one buffer for transmit All these actions in total require 17 + (14 x 3) + 2 = 61 clock cycles to be executed by the CAN module. This leads to the limitation of the Bit Time Logic of 61 / 4 = 15.25 clock cycles per CAN bit as a minimum, resulting in the minimum clock frequencies listed below. (The frequency depends on the desired baud rate and assumes the worst case scenario can occur in the application.) 17.11.6 Remote Frames Remote frames can be automatically processed by the CAN module. However, to fully enable this feature, the RTR/ XRTR bits (for both standard and extended frames) within the BMSK and/or GMSK register need to be set to "don't care". This is because a remote frame with the RTR bit set should trigger the transmission of a data frame with the RTR bit clear and therefore the ID bits of the received message need to pass through the acceptance filter. The same applies to transmitting remote frames and switching to receive the corresponding data frames.
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17.12
USAGE HINT
Under certain conditions, the CAN module receives a frame sent by itself, even though the loopback feature is disabled. Two conditions must be true to cause this malfunction: A transmit buffer and at least one receive buffer are configured with the same identifier. Assume this identifier is called ID_RX_TX. With regard to the receive buffer, this means that the buffer identifier and the corresponding filter masks are set up in a way that the buffer is able to receive frames with the identifier ID_RX_TX. The following sequence of events occurs: 1. A message with the identifier ID_RX_TX from another CAN node is received into the receive buffer. 2. A message with the identifier ID_RX_TX is sent by the CAN module immediately after the reception took place. When these conditions occur, the frame sent by the CAN module will be copied into the next receive buffer available for the identifier ID_RX_TX. If a frame with an identifier different to ID_RX_TX is sent or received in between events 1 and 2, the problem does not occur.
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18.0 Advanced Audio Interface
The Advanced Audio Interface (AAI) provides a serial synchronous, full duplex interface to codecs and similar serial devices. The transmit and receive paths may operate asynchronously with respect to each other. Each path uses a 3wire interface consisting of a bit clock, a frame synchronization signal, and a data signal. The CPU interface can be either interrupt-driven or DMA. If the interface is configured for interrupt-driven I/O, data is buffered in the receive and transmit FIFOs. If the interface is configured for DMA, the data is buffered in registers. 18.1.4 Serial Receive Data (SRD) The SRD pin is used as an input when data is shifted into the Audio Receive Shift Register (ARSR). In asynchronous mode, data on the SRD pin is sampled on the negative edge of the serial receive shift clock (SRCLK). In synchronous mode, data on the SRD pin is sampled on the negative edge of the serial shift clock (SCK). The data is shifted into ARSR with the most significant bit (MSB) first. 18.1.5 Serial Receive Clock (SRCLK)
The SRCLK pin is a bidirectional signal that provides the reThe AAI is functionally similar to a MotorolaTM Synchronous ceive serial shift clock in asynchronous mode. In this mode, Serial Interface (SSI). Compared to a standard SSI impledata is sampled on the negative edge of SRCLK. The SRmentation, the AAI interface does not support the so-called CLK signal may be generated internally or it may be provid"On-demand Mode". It also does not allow gating of the shift ed by an external clock source. In synchronous mode, the clocks, so the receive and transmit shift clocks are always SCK pin is used as shift clock for both the receiver and active while the AAI is enabled. The AAI also does not suptransmitter, so the SRCLK pin is available for use as a genport 12- and 24-bit data word length or more than 4 slots eral-purpose port pin or an auxiliary frame sync signal to ac(words) per frame. The reduction of supported modes is access multiple slave devices (e.g. codecs) within a network ceptable, because the main purpose of the AAI is to connect (see Network mode). to audio codecs, rather than to other processors (DSPs). The implementation of a FIFO as a 16-word receive and 18.1.6 Serial Receive Frame Sync (SRFS) transmit buffer is an additional feature, which simplifies communication and reduces interrupt load. Independent DMA is provided for each of the four supported audio channels (slots). The AAI also provides special features and operating modes to simplify gain control in an external codec and to connect to an ISDN controller through an IOM-2 compatible interface. The SRFS pin is a bidirectional signal that provides frame synchronization for the receiver in asynchronous mode. The frame sync signal may be generated internally, or it may be provided by an external source. In synchronous mode, the SFS signal is used as the frame sync signal for both the transmitter and receiver, so the SRFS pin is available for use as a general-purpose port pin or an auxiliary frame sync signal to access multiple slave devices (e.g. codecs) within a network (see Network mode).
18.1
18.1.1
AUDIO INTERFACE SIGNALS
Serial Transmit Data (STD)
18.2
AUDIO INTERFACE MODES
The STD pin is used to transmit data from the serial transmit shift register (ATSR). The STD pin is an output when data is being transmitted and is in high-impedance mode when no data is being transmitted. The data on the STD pin changes on the positive edge of the transmit shift clock (SCK). The STD pin goes into high-impedance mode on the negative edge of SCK of the last bit of the data word to be transmitted, assuming no other data word follows immediately. If another data word follows immediately, the STD pin remains active rather than going to the high-impedance mode. 18.1.2 Serial Transmit Clock (SCK)
There are two clocking modes: asynchronous mode and synchronous mode. These modes differ in the source and timing of the clock signals used to transfer data. When the AAI is generating the bit shift clock and frame sync signals internally, synchronous mode must be used. There are two framing modes: normal mode and network mode. In normal mode, one word is transferred per frame. In network mode, up to four words are transferred per frame. A word may be 8 or 16 bits. The part of the frame which carries a word is called a slot. Network mode supports multiple external devices sharing the interface, in which each device is assigned its own slot. Separate frame sync signals are provided, so that each device is triggered to send or receive its data during its assigned slot. 18.2.1 Asynchronous Mode
The SCK pin is a bidirectional signal that provides the serial shift clock. In asynchronous mode, this clock is used only by the transmitter to shift out data on the positive edge. The serial shift clock may be generated internally or it may be provided by an external clock source. In synchronous mode, the SCK pin is used by both the transmitter and the receiver. Data is shifted out from the STD pin on the positive edge, and data is sampled on the SRD pin on the negative edge. 18.1.3 Serial Transmit Frame Sync (SFS)
The SFS pin is a bidirectional signal which provides frame synchronization. In asynchronous mode, this signal is used as frame sync only by the transmitter. In synchronous mode, this signal is used as frame sync by both the transmitter and receiver. The frame sync signal may be generated internally, or it may be provided by an external source. www.national.com
In asynchronous mode, the receive and transmit paths of the audio interface operate independently, with each path using its own bit clock and frame sync signal. Independent clocks for receive and transmit are only used when the bit clock and frame sync signal are supplied externally. If the bit clock and frame sync signals are generated internally, both paths derive their clocks from the same set of clock prescalers.
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18.2.2
Synchronous Mode
In synchronous mode, the receive and transmit paths of the audio interface use the same shift clock and frame sync signal. The bit shift clock and frame sync signal for both paths are derived from the same set of clock prescalers. 18.2.3 Normal Mode
data bytes or words available in the transmit FIFO is equal or less than a programmable warning limit. DMA Support If the receiver interface is configured for DMA (RXDSA0 = 1), received data is transferred from the ARSR into the DMA receive buffer 0 (ARDR0). A DMA request is asserted when the ARDR0 register is full. If the transmitter interface is configured for DMA (TXDSA0 = 1), data to be transmitted are read from the DMA transmit buffer 0 (ATDR0). A DMA request is asserted to the DMA controller when the ATDR0 register is empty.
In normal mode, each rising edge on the frame sync signal marks the beginning of a new frame and also the beginning of a new slot. A slot does not necessarily occupy the entire frame. (A frame can be longer than the data word transmitted after the frame sync pulse.) Typically, a codec starts transmitting a fixed length data word (e.g. 8-bit log PCM da- Figure 48 shows the data flow for IRQ and DMA mode in ta) with the frame sync signal, then the codec's transmit pin normal Mode. returns to the high-impedance state for the remainder of the DMA frame. SRD
Request 1
The Audio Receive Shift Register (ARSR) de-serializes received on the SRD pin (serial receiver data). Only the data sampled after the frame sync signal are treated as valid. If the interface is interrupt-driven, valid data bits are transferred from the ARSR to the receive FIFO. If the interface is configured for DMA, the data is transferred to the receive DMA register 0 (ARDR0). The serial transmit data (STD) pin is only an active output while data is shifted out. After the defined number of data bits have been shifted out, the STD pin returns to the highimpedance state. For operation in normal mode, the Slot Count Select bits (SCS[1:0]) in the Global Configuration register (AGCR) must be loaded with 00b (one slot per frame). In addition, the Slot Assignment bits for receive and transmit must be programmed to select slot 0. If the interface is configured for DMA, the DMA slot assignment bits must also be programmed to select slot 0. In this case, the audio data is transferred to or from the receive or transmit DMA register 0 (ARDR0/ATDR0).
ARSR
A DS TX =1
ARDR 0
DMA Slot Assignment
TXDSA = 0
RX FIFO
IRQ
STD ATSR
D RX SA =1
DMA Request 0 ATDR 0
DMA Slot Assignment
RXDSA = 0
TX FIFO
IRQ DS054
Figure 48. IRQ/DMA Support in Normal Mode Network Mode
In network mode, each frame is composed of multiple slots. Each slot may transfer 8 or 16 bits. All of the slots in a frame must have the same length. In network mode, the sync signal marks the beginning of a new frame. Only frames with Figure 47 shows the frame timing while operating in normal up to four slots are supported by this audio interface. mode with a long frame sync interval. More than two devices can communicate within a network using the same clock and data lines. The devices connected to the same bus use a time-multiplexed approach to share Long Frame Sync access to the bus. Each device has certain slots assigned (SFS/SRFS) to it, in which only that device is allowed to transfer data. One master device provides the bit clock and the frame sync High-impedance signal(s). On all other (slave) devices, the bit clock and Shift Data Data Data (STD/SRD) frame sync pins are inputs.
Frame
DS053
Up to four slots can be assigned to the interface, as it supports up to four slots per frame. Any other slots within the frame are reserved for other devices.
The transmitter only drives data on the STD pin during slots which have been assigned to this interface. During all other If the receiver interface is configured for interrupt-driven I/O slots, the STD output is in high-impedance mode, and data (RXDSA0 = 0), all received data are loaded into the receive can be driven by other devices. The assignment of slots to FIFO. An IRQ is asserted as soon as the number of data the transmitter is specified by the Transmit Slot Assignment bytes or words in the receive FIFO is greater than a pro- bits (TXSA) in the ATCR register. It can also be specified whether the data to be transmitted is transferred from the grammable warning limit. transmit FIFO or the corresponding DMA transmit register. If the transmitter interface is configured for interrupt-driven There is one DMA transmit register (ATDRn) for each of the I/O (TXDSA0 = 0), all data to be transmitted is read from the maximum four data slots. Each slot can be configured indetransmit FIFO. An IRQ is asserted as soon as the number pendently. IRQ Support
Figure 47.
Normal Mode Frame
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On the receiver side, only the valid data bits which were re- port enabled for slots 0 and 1 in receive and transmit direcceived during the slots assigned to this interface are copied tion. into the receive FIFO or DMA registers. The assignment of DMA slots to the receiver is specified by the Receive Slot AssignRequest 1 ARDR 0 ment bits (RXSA) in the ATCR register. It can also be specDMA ified whether the received data is copied into the receive SRD Request 3 ARSR ARDR 1 FIFO or into the corresponding DMA receive register. There is one DMA receive register (ARDRn) for each of the maxiata ARDR 2 mum four data slots. Each slot may be configured individu1d ot Sl DMA Slot ally.
Assignment
Sl ot 0 da ta
Figure 49 shows the frame timing while operating in network mode with four slots per frame, slot 1 assigned to the interface, and a long frame sync interval.
Long Frame Sync (SFS/SRFS)
Sl
ot
ARDR 3
2
an
d
3
da
ta
RX FIFO
IRQ
Shift Data (STD/SRD)
Data (ignored)
Data (valid)
High-impedance
Data (ignored)
ATDR 0 STD
da
DMA Request 0 DMA Request 2
ATSR
Sl ot
ta
Slot0
Slot1
Unused Slots
0
ATDR 1
1d ata
Frame DS055
DMA Slot Assignment
ot Sl
ATDR 2
Sl
ATDR 3
Figure 49. IRQ Support
Network Mode Frame
ot
2
an
d
3
da
ta
If DMA is not enabled for a receive slot n (RXDSAn = 0), all DS056 data received in this slot is loaded into the receive FIFO. An IRQ is asserted as soon as the number of data bytes or Figure 50. IRQ/DMA Support in Network Mode words in the receive FIFO is greater than a configured warnIf the interface operates in synchronous mode, the receiver ing limit. uses the transmit bit clock (SCK) and transmit frame sync If DMA is not enabled for a transmit slot n (TXDSAn = 0), all signal (SFS). This allows the pins used for the receive bit data to be transmitted in this slot are read from the transmit clock (SRCLK) and receive frame sync (SRFS) to be used FIFO. An IRQ is asserted as soon as the number data bytes as additional frame sync signals in network mode. The extra or words available in the transmit FIFO is equal or less than frame sync signals are useful when the audio interface coma configured warning limit. municates to more than one codec, because codecs typically start transmission immediately after the frame sync pulse. DMA Support If DMA support is enabled for a receive slot n (RXDSA0 = The SRCLK pin is driven with a frame sync pulse at the be1), all data received in this slot is only transferred from the ginning of the second slot (slot 1), and the SRFS pin is drivARSR into the corresponding DMA receive register en with a frame sync pulse at the beginning of slot 2. (ARDRn). A DMA request is asserted when the ARDRn reg- Figure 51 shows a frame timing diagram for this configuration, using the additional frame sync signals on SRCLK and ister is full. SRFS to address up to three devices. If DMA is enabled for a transmit slot n (TXDSAn = 1), all data to be transmitted in slot n are read from the corresponding DMA transmit register (ATDRn). A DMA request is asserted to the DMA controller when the ATDRn register is empty. Figure 50 illustrates the data flow for IRQ and DMA support in network mode, using four slots per frame and DMA sup-
TX FIFO
IRQ
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The ideal required prescaler value Pideal can be calculated as follows:
SFS
Pideal = fAudio In / fbit = 12 MHz / 256 kHz = 46.875 Therefore, the real prescaler value is 47. This results in a bit clock error equal to: fbit_error = (fbit - fAudio In/Preal) / fbit x 100 = (256 kHz - 12 MHz/47) / 256 kHz x 100 = 0.27%
SRCLK (auxiliary frame sync) SRFS (auxiliary frame sync) Data from/to Data from/to Data from/to Codec 1 Codec 2 Codec 3 Slot0 Slot1 Slot2 Slot2
18.4
FRAME CLOCK GENERATION
STD/SRD
Frame DS057
Figure 51.
Accessing Three Devices in Network Mode
18.3
BIT CLOCK GENERATION
The clock for the frame synchronization signals is derived from the bit clock of the audio interface. A 7-bit prescaler is used to divide the bit clock to generate the frame sync clock for the receive and transmit operations. The bit clock is divided by FCPRS + 1. In other words, the value software must write into the ACCR.FCPRS field is equal to the bit number per frame minus one. The frame may be longer than the valid data word but it must be equal to or larger than the 8- or 16-bit word. Even if 13-, 14-, or 15-bit data is being used, the frame width must always be at least 16 bits wide. In addition, software can specify the length of a long frame sync signal. A long frame sync signal can be either 6, 13, 14, 15, or 16 bits long, depending on the external codec being used. The frame sync length can be configured by the Frame Sync Length field (FSL) in the AGCR register.
An 8-bit prescaler is provided to divide the audio interface input clock down to the required bit clock rate. Software can choose between two input clock sources, a primary and a secondary clock source. On the CP3CN23, the two optional input clock sources are the 12-MHz Aux1 clock and the 48-MHz PLL output clock. The input clock is divided by the value of the prescaler BCPRS[7:0] + 1 to generate the bit clock.
18.5
AUDIO INTERFACE OPERATION
18.5.1 Clock Configuration The bit clock rate fbit can be calculated by the following The Aux1 clock (generated by the Clock module described equation: in Section 11.9) must be configured, because it is the time base for the AAI module. Software must write an approprifbit = n x fSample x Data Length ate divisor to the ACDIV1 field of the PRSAC register to pron = Number of Slots per Frame vide a 12 MHz input clock. Software also must enable the fSample = Sample Frequency in Hz Aux1 clock by setting the ACE1 bit in the CRCTRL register. Data Length = Length of data word in multiples of 8 bits For example: The ideal required prescaler value Pideal can be calculated PRSAC &= 0xF0; as follows: // Set Aux1 prescaler to 1 (F = 12 MHz) CRCTRL |= ACE1; // Enable Aux1 clk The real prescaler must be set to an integer value, which 18.5.2 Interrupts should be as close as possible to the ideal prescaler value, The interrupt logic of the AAI combines up to four interrupt to minimize the bit clock error, fbit_error. sources and generates one interrupt request signal to the fbit_error [%] = (fbit - fAudio In/Preal) / fbit x 100 Interrupt Control Unit (ICU). Example: The four interrupt sources are: The audio interface is used to transfer 13-bit linear PCM data for one audio channel at a sample rate of 8k samples per second. The input clock of the audio interface is 12 MHz. Furthermore, the codec requires a minimum bit clock of 256 kHz to operate properly. Therefore, the number of slots per frame must be set to 2 (network mode) although actually only one slot (slot 0) is used. The codec and the audio interface will put their data transmit pins in TRI-STATE mode after the PCM data word has been transferred. The required bit clock rate fbit can be calculated by the following equation: fbit = n x fSample x Data Length = 2 x 8 kHz x 16 = 256 kHz RX FIFO Overrun - ASCR.RXEIP = 1 RX FIFO Almost Full (Warning Level) - ASCR.RXIP = 1 TX FIFO Under run - ASCR.TXEIP = 1 TX FIFO Almost Empty (Warning Level) - ASCR.TXIP=1 In addition to the dedicated input to the ICU for handling these interrupt sources, the Serial Frame Sync (SFS) signal is an input to the MIWU (see Section 13.0), which can be programmed to generate edge-triggered interrupts. Pideal = fAudio In / fbit
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Figure 52 shows the interrupt structure of the AAI.
RXIE
RXIP = 1
event, the read pointer (TRP) will be decremented by 1 (incremented by 15) and the previous data word will be transmitted again. A transmit FIFO underrun is indicated by the TXU bit in the Audio Interface Transmit Status and Control Register (ATSCR). Also, no transmit interrupt will be generated (even if enabled). When the TRP is equal to the TWP and the last access to the FIFO was a write operation (to the ATFR), the FIFO is full. If an additional write to ATFR is performed, a transmit FIFO overrun occurs. This error condition is not prevented by hardware. Software must ensure that no transmit overrun occurs. The transmit frame synchronization pulse on the SFS pin and the transmit shift clock on the SCK pin may be generated internally, or they can be supplied by an external source. 18.5.5 Receive
RXEIE
RXEIP = 1
AAI Interrupt TXIE
TXIP = 1
TXEIE
TXEIP = 1 DS155
Figure 52. AAI Interrupt Structure 18.5.3 Normal Mode
At the receiver, the received data on the SRD pin is shifted into ARSR on the negative edge of SRCLK (or SCK in synchronous mode), following the receive frame sync pulse, SRFS (or SFS in synchronous mode). DMA Operation When a complete data word has been received through the SRD pin, the new data word is copied to the receive DMA register 0 (ARDR0). A DMA request is asserted when the ARDR0 register is full. If a new data word is received while the ARDR0 register is still full, the ARDR0 register will be overwritten with the new data. FIFO Operation When a complete word has been received, it is transferred to the receive FIFO at the current location of the Receive FIFO Write Pointer (RWP). Then, the RWP is automatically incremented by 1. A read from the Audio Receive FIFO Register (ARFR) results in a read from the receive FIFO at the current location of the Receive FIFO Read Pointer (RRP). After every read operation from the receive FIFO, the RRP is automatically incremented by 1.
In normal mode, each frame sync signal marks the beginning of a new frame and also the beginning of a new slot, since each frame only consists of one slot. All 16 receive and transmit FIFO locations hold data for the same (and only) slot of a frame. If 8-bit data are transferred, only the low byte of each 16-bit FIFO location holds valid data. 18.5.4 Transmit
Once the interface has been enabled, transmit transfers are initiated automatically at the beginning of every frame. The beginning of a new frame is identified by a frame sync pulse. Following the frame sync pulse, the data is shifted out from the ATSR to the STD pin on the positive edge of the transmit data shift clock (SCK). DMA Operation
When a complete data word has been transmitted through the STD pin, a new data word is reloaded from the transmit DMA register 0 (ATDR0). A DMA request is asserted when When the RRP is equal to the RWP and the last access to the ATDR0 register is empty. If a new data word must be the FIFO was a copy operation from the ARFR, the receive transmitted while the ATDR0 register is still empty, the preFIFO is full. When a new complete data word has been shiftvious data will be re-transmitted. ed into ARSR while the receive FIFO was already full, the shift register overruns. In this case, the new data in the FIFO Operation ARSR will not be copied into the FIFO and the RWP will not When a complete data word has been transmitted through be incremented. A receive FIFO overrun is indicated by the the STD pin, a new data word is loaded from the transmit RXO bit in the Audio Interface Receive Status and Control FIFO from the current location of the Transmit FIFO Read Register (ARSCR). No receive interrupt will be generated Pointer (TRP). After that, the TRP is automatically incre(even if enabled). mented by 1. When the RWP is equal to the RRP and the last access to A write to the Audio Transmit FIFO Register (ATFR) results the receive FIFO was a read from the ARFR, a receive FIFO in a write to the transmit FIFO at the current location of the underrun has occurred. This error condition is not prevented Transmit FIFO Write Pointer (TWP). After every write operby hardware. Software must ensure that no receive underation to the transmit FIFO, TWP is automatically incrementrun occurs. ed by 1. The receive frame synchronization pulse on the SRFS pin When the TRP is equal to the TWP and the last access to (or SFS in synchronous mode) and the receive shift clock on the FIFO was a read operation (a transfer to the ATSR), the the SRCLK (or SCK in synchronous mode) may be genertransmit FIFO is empty. When an additional read operation ated internally, or they can be supplied by an external from the FIFO to ATSR is performed (while the FIFO is alsource. ready empty), a transmit FIFO underrun occurs. In this www.national.com 120
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18.5.6
Network Mode
DMA Operation When a complete data word has been received through the SRD pin in a slot n, the new data word is transferred to the corresponding receive DMA register n (ARDRn). A DMA request is asserted when the ARDRn register is full. If a new slot n data word is received while the ARDRn register is still full, the ARDRn register will be overwritten with the new data. FIFO Operation When a complete word has been received, it is transferred to the receive FIFO at the current location of the Receive FIFO Write Pointer (RWP). After that, the RWP is automatically incremented by 1. Therefore, data received in the next slot is copied to the next higher FIFO location.
In network mode, each frame sync signal marks the beginning of new frame. Each frame can consist of up to four slots. The audio interface operates in a similar way to normal mode, however, in network mode the transmitter and receiver can be assigned to specific slots within each frame as described below. 18.5.7 Transmit
The transmitter only shifts out data during the assigned slot. During all other slots the STD output is in TRI-STATE mode. DMA Operation
When a complete data word has been transmitted through the STD pin, a new data word is reloaded from the corresponding transmit DMA register n (ATDRn). A DMA request A read from the Audio Receive FIFO Register (ARFR) reis asserted when ATDRn is empty. If a new data word must sults in a read from the receive FIFO at the current location be transmitted in a slot n while ATDRn is still empty, the preof the Receive FIFO Read Pointer (RRP). After every read vious slot n data will be retransmitted. operation from the receive FIFO, the RRP is automatically FIFO Operation incremented by 1. When a complete data word has been transmitted through the STD pin, a new data word is reloaded from the transmit FIFO from the current location of the Transmit FIFO Read Pointer (TRP). After that, the TRP is automatically incremented by 1. Therefore, the audio data to be transmitted in the next slot of the frame is read from the next FIFO location. When the RRP is equal to the RWP and the last access to the FIFO was a transfer to the ARFR, the receive FIFO is full. When a new complete data word has been shifted into the ARSR while the receive FIFO was already full, the shift register overruns. In this case, the new data in the ARSR will not be transferred to the FIFO and the RWP will not be incremented. A receive FIFO overrun is indicated by the RXO A write to the Audio Transmit FIFO Register (ATFR) results bit in the Audio Interface Receive Status and Control Regisin a write to the transmit FIFO at the current location of the ter (ARSCR). No receive interrupt will be generated (even if Transmit FIFO Write Pointer (TWP). After every write oper- enabled). ation to the transmit FIFO, the TWP is automatically incre- When the current RWP is equal to the TWP and the last acmented by 1. cess to the receive FIFO was a read from ARFR, a receive When the TRP is equal to the TWP and the last access to FIFO underrun has occurred. This error condition is not prethe FIFO was a read operation (transfer to the ATSR), the vented by hardware. Software must ensure that no receive transmit FIFO is empty. When an additional read operation underrun occurs. from the FIFO to the ATSR is performed (while the FIFO is already empty), a transmit FIFO underrun occurs. In this case, the read pointer (TRP) will be decremented by 1 (incremented by 15) and the previous data word will be transmitted again. A transmit FIFO underrun is indicated by the TXU bit in the Audio Interface Transmit Status and Control Register (ATSCR). No transmit interrupt will be generated (even if enabled). If the current TRP is equal to the TWP and the last access to the FIFO was a write operation (to the ATFR), the FIFO is full. If an additional write to the ATFR is performed, a transmit FIFO overrun occurs. This error condition is not prevented by hardware. Software must ensure that no transmit overrun occurs. The receive frame synchronization pulse on the SRFS pin (or SFS in synchronous mode) and the receive shift clock on the SRCLK (or SCK in synchronous mode) may be generated internally, or they can be supplied by an external source.
18.6
18.6.1
COMMUNICATION OPTIONS
Data Word Length
The word length of the audio data can be selected to be either 8 or 16 bits. In 16-bit mode, all 16 bits of the transmit and receive shift registers (ATSR and ARSR) are used. In 8bit mode, only the lower 8 bits of the transmit and receive shift registers (ATSR and ARSR) are used.
18.6.2 Frame Sync Signal The transmit frame synchronization pulse on the SFS pin and the transmit shift clock on the SCK pin may be generat- The audio interface can be configured to use either long or ed internally, or they can be supplied by an external source. short frame sync signals to mark the beginning of a new data frame. If the corresponding Frame Sync Select (FSS) 18.5.8 Receive bit in the Audio Control and Status register is clear, the reThe receive shift register (ARSR) receives data words of all ceive and/or transmit path generates or recognizes short slots in the frame, regardless of the slot assignment of the frame sync pulses with a length of one bit shift clock period. interface. However, only those ARSR contents are trans- When these short frame sync pulses are used, the transfer ferred to the receive FIFO or DMA receive register which of the first data bit or the first slot begins at the first positive were received during the assigned time slots. A receive in- edge of the shift clock after the negative edge on the frame sync pulse. terrupt or DMA request is initiated when this occurs.
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If the corresponding Frame Sync Select (FSS) bit in the Audio Control and Status register is set, the receive and/or transmit path generates or recognizes long frame sync pulses. For 8-bit data, the frame sync pulse generated will be 6 bit shift clock periods long, and for 16-bit data the frame sync pulse can be configured to be 13, 14, 15, or 16 bit shift clock periods long. When receiving frame sync, it should be active on the first bit of data and stay active for a least two bit clock periods. It must go low for at least one bit clock period before starting a new frame. When long frame sync pulses are used, the transfer of the first word (first slot) begins at the first positive edge of the bit shift clock after the positive edge of the frame sync pulse. Figure 53 shows examples of short and long frame sync pulses.
Some codecs require an inverted frame sync signal. This is available by setting the Inverted Frame Sync bit in the AGCR register. 18.6.3 Audio Control Data
Bit Shift Clock (SCK/SRCLK)
Shift Data (STD/SRD)
D0
D1
D2
D3
D4
D5
D6
D7
The audio interface provides the option to fill a 16-bit slot with up to three data bits if only 13, 14, or 15 PCM data bits are transmitted. These additional bits are called audio control data and are appended to the PCM data stream. The AAI can be configured to append either 1, 2, or 3 audio control bits to the PCM data stream. The number of audio data bits to be used is specified by the 2-bit Audio Control On (ACO) field. If the ACO field is not equal to 0, the specified number of bits are taken from the Audio Control Data field (ACD) and appended to the data stream during every transmit operation. The ADC0 bit is the first bit added to the transmit data stream after the last PCM data bit. Typically, these bits are used for gain control, if this feature is supported by the external PCM codec.Figure 54 shows a 16-bit slot comprising a 13-bit PCM data word plus three audio control bits.
Short Frame Sync Pulse
Long Frame Sync Pulse DS156
Figure 53. Short and Long Frame Sync Pulses
SCK
SFS
STD
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10 D11
D12 ACD2 ACD1 ACD0 Audio Control Bits
13-bit PCM Data Word
16-bit Slot DS161
Figure 54. Audio Slot with Audio Control Data
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18.6.4
IOM-2 Mode
The IOM-2 interface has the following properties:
The AAI can operate in a special IOM-2 compatible mode to Bit clock of 1536 kHz (output from the ISDN controller) allow to connect to an external ISDN controller device. In Frame repetition rate of 8 ksps (output from the ISDN this IOM-2 mode, the AAI can only operate as a slave, i.e. controller) the bit clock and frame sync signal is provided by the ISDN Double-speed bit clock (one data bit is two bit clocks controller. The AAI only supports the B1 and B2 data of the wide) IOM-2 channel 0, but ignores the other two IOM-2 channels. B1 and B2 data use 8-bit log PCM format The AAI handles the B1 and B2 data as one 16-bit data Long frame sync pulse word. Figure 55 shows the structure of an IOM-2 Frame.
SFS
STD/SRD
B1
B2
M
C
IC1
IC2
M
C
C
IOM-2 Channel 0
IOM-2 Channel 1
IOM-2 Channel 2
IOM-2 Frame (125 s) DS162
Figure 55. IOM-2 Frame Structure Figure 56 shows the connections between an ISDN controller and a CP3CN23 using a standard IOM-2 interface for the B1/B2 data communication and the external bus interface (IO Expansion) for controlling the ISDN controller. To connect the AAI to an ISDN controller through an IOM-2 compatible interface, the AAI needs to be configured in this way: The AAI must be in IOM-2 Mode (AGCR.IOM2 = 1). The AAI operates in synchronous mode (AGCR.ASS = 0). The AAI operates as a slave, therefore the bit clock and frame sync source selection must be set to external (ACGR.IEFS = 1, ACGR.IEBC = 1). The frame sync length must be set to long frame sync (ACGR.FSS = 1). The data word length must be set to 16-bit (AGCR.DWL = 1). The AAI must be set to normal mode (AGCR.SCS[1:0] = 0). The internal frame rate must be 8 ksps (ACCR = 00BE). 18.6.5 Loopback Mode
SCK
Bit Clock
SFS
Frame Sync
CP3BT2x
STD
ISDN Controller
Data In
SRD
Data Out
A[7:0]
Address
D[7:0]
Data
SELIO
Chip Select
RD
Output Enable
DS241
In loopback mode, the STD and SRD pins are internally connected together, so data shifted out through the ATSR register will be shifted into the ARSR register. This mode may be used for development, but it also allows testing the transmit and receive path without external circuitry, for example during Built-In-Self-Test (BIST).
Figure 56. CP3CN23/ISDN Controller Connections
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18.6.6
Freeze Mode
18.7
AUDIO INTERFACE REGISTERS
Table 57 Audio Interface Registers Name ARFR ARDR0 ARDR1 ARDR2 ARDR3 ATFR ATDR0 ATDR1 ATDR2 ATDR3 AGCR AISCR ARSCR ATSCR ACCR Address FF FD40h FF FD42h FF FD44h FF FD46h FF FD48h FF FD4Ah FF FD4Ch FF FD4Eh FF FD50h FF FD52h FF FD54h FF FD56h FF FD58h FF FD5Ah FF FD5Ch FF FD5Eh Description Audio Receive FIFO Register Audio Receive DMA Register 0 Audio Receive DMA Register 1 Audio Receive DMA Register 2 Audio Receive DMA Register 3 Audio Transmit FIFO Register Audio Transmit DMA Register 0 Audio Transmit DMA Register 1 Audio Transmit DMA Register 2 Audio Transmit DMA Register 3 Audio Global Configuration Register Audio Interrupt Status and Control Register Audio Receive Status and Control Register Audio Transmit Status and Control Register Audio Clock Control Register Audio DMA Control Register
The audio interface provides a FREEZE input, which allows to freeze the status of the audio interface while a development system examines the contents of the FIFOs and registers. When the FREEZE input is asserted, the audio interface behaves as follows: The receive FIFO or receive DMA registers are not updated with new data. The receive status bits (RXO, RXE, RXF, and RXAF) are not changed, even though the receive FIFO or receive DMA registers are read. The transmit shift register (ATSR) is not updated with new data from the transmit FIFO or transmit DMA registers. The transmit status bits (TXU, TXF, TXE, and TXAE) are not changed, even though the transmit FIFO or transmit DMA registers are written. The time at which these registers are frozen will vary because they operate from a different clock than the one used to generate the freeze signal.
ADMACR
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18.7.1
Audio Receive FIFO Register (ARFR)
18.7.3
Audio Transmit FIFO Register (ATFR)
The Audio Receive FIFO register shows the receive FIFO location currently addressed by the Receive FIFO Read Pointer (RRP). The receive FIFO receives 8-bit or 16-bit data from the Audio Receive Shift Register (ARSR), when the ARSR is full. In 8-bit mode, only the lower byte of the ARFR is used, and the upper byte contains undefined data. In 16-bit mode, a 16-bit word is copied from ARSR into the receive FIFO. The CPU bus master has read-only access to the receive FIFO, represented by the ARFR register. After reset, the receive FIFO (ARFR) contains undefined data. 7 ARFL 0
The ATFR register shows the transmit FIFO location currently addressed by the Transmit FIFO Write Pointer (TWP). The Audio Transmit Shift Register (ATSR) receives 8-bit or 16-bit data from the transmit FIFO, when the ATSR is empty. In 8-bit mode, only the lower 8-bit portion of the ATSR is used, and the upper byte is ignored (not transferred into the ATSR). In 16-bit mode, a 16-bit word is copied from the transmit FIFO into the ATSR. The CPU bus master has write-only access to the transmit FIFO, represented by the ATFR register. After reset, the transmit FIFO (ATFR) contains undefined data. 7 ATFL 0
15 ARFH
8
15 ATFH
8
ARFL
ARFH
The Audio Receive FIFO Low Byte shows the lower byte of the receive FIFO location currently addressed by the Receive FIFO Read Pointer (RRP). The Audio Receive FIFO High Byte shows the upper byte of the receive FIFO location currently addressed by the Receive FIFO Read Pointer (RRP). In 8-bit mode, ARFH contains undefined data. Audio Receive DMA Register n (ARDRn)
ATFL
ATFH
The Audio Transmit Low Byte field represents the lower byte of the transmit FIFO location currently addressed by the Transmit FIFO Write Pointer (TWP). In 16-bit mode, the Audio Transmit FIFO High Byte field represents the upper byte of the transmit FIFO location currently addressed by the Transmit FIFO Write Pointer (TWP). In 8bit mode, the ATFH field is not used. Audio Transmit DMA Register n (ATDRn)
18.7.2
18.7.4
The ARDRn register contains the data received within slot n, assigned for DMA support. In 8-bit mode, only the lower 8-bit portion of the ARDRn register is used, and the upper byte contains undefined data. In 16-bit mode, a 16-bit word is transferred from the Audio Receive Shift Register (ARSR) into the ARDRn register. The CPU bus master, typically a DMA controller, has read-only access to the receive DMA registers. After reset, these registers are clear. 7 ARDL 0
The ATDRn register contains the data to be transmitted in slot n, assigned for DMA support. In 8-bit mode, only the lower 8-bit portion of the ATDRn register is used, and the upper byte is ignored (not transferred into the ATSR). In 16bit mode, the whole 16-bit word is transferred into the ATSR. The CPU bus master, typically a DMA controller, has writeonly access to the transmit DMA registers. After reset, these registers are clear. 7 ATDL 0
15 ARDH
8
15 ATDH
8
ARDL
ARDH
The Audio Receive DMA Low Byte field receives the lower byte of the audio data copied from the ARSR. In 16-bit mode, the Audio Receive DMA High Byte field receives the upper byte of the audio data word copied from ARSR. In 8-bit mode, the ARDH register holds undefined data.
ATDL ATDH
The Audio Transmit DMA Low Byte field holds the lower byte of the audio data. In 16-bit mode, the Audio Transmit DMA High Byte field holds the upper byte of the audio data word. In 8-bit mode, the ATDH field is ignored.
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18.7.5
Audio Global Configuration Register (AGCR)
IEFS
The AGCR register controls the basic operation of the interface. The CPU bus master has read/write access to the AGCR register. After reset, this register is clear. 7 IEBC 6 FSS 5 IEFS 4 SCS 3 2 LPB 1 DWL 0 ASS FSS 15 14 13 12 IFS 11 10 9 CTF 8 CRF CLKEN AAIEN IOM2 FSL
ASS
DWL
LPB
SCS
The Asynchronous/Synchronous Mode Select bit controls whether the audio interface operates in Asynchronous or in Synchronous mode. After reset the ASS bit is clear, so the Synchronous mode is selected by default. 0 - Synchronous mode. 1 - Asynchronous mode. The Data Word Length bit controls whether the transferred data word has a length of 8 or 16 bits. After reset, the DWL bit is clear, so 8bit data words are used by default. 0 - 8-bit data word length. 1 - 16-bit data word length. The Loop Back bit enables the loop back mode. In this mode, the SRD and STD pins are internally connected. After reset the LPB bit is clear, so by default the loop back mode is disabled. 0 - Loop back mode disabled. 1 - Loop back mode enabled. The Slot Count Select field specifies the number of slots within each frame. If the number of slots per frame is equal to 1, the audio interface operates in normal mode. If the number of slots per frame is greater than 1, the interface operates in network mode. After reset all SCS bits are cleared, so by default the audio interface operates in normal mode. Number of Slots per Frame 1 2 3 4
IEBC
CRF
CTF
FSL
SCS
Mode
00 01 10 11
Normal mode Network mode Network mode Network mode
The Internal/External Frame Sync bit controls, whether the frame sync signal for the receiver and transmitter are generated internally or provided from an external source. After reset, the IEFS bit is clear, so the frame synchronization signals are generated internally by default. 0 - Internal frame synchronization signal. 1 - External frame synchronization signal. The Frame Sync Select bit controls whether the interface (receiver and transmitter) uses long or short frame synchronization signals. After reset the FSS bit is clear, so short frame synchronization signals are used by default. 0 - Short (bit length) frame synchronization signal. 1 - Long (word length) frame synchronization signal. The Internal/External Bit Clock bit controls whether the bit clocks for receiver and transmitter are generated internally or provided from an external source. After reset, the IEBC bit is clear, so the bit clocks are generated internally by default. 0 - Internal bit clock. 1 - External bit clock. The Clear Receive FIFO bit is used to clear the receive FIFO. When this bit is written with a 1, all pointers of the receive FIFO are set to their reset state. After updating the pointers, the CRF bit will automatically be cleared again. 0 - Writing 0 has no effect. 1 - Writing 1 clears the receive FIFO. The Clear Transmit FIFO bit is used to clear the transmit FIFO. When this bit is written with a 1, all pointers of the transmit FIFO are set to their reset state. After updating the pointers, the CTF bit will automatically be cleared again. 0 - Writing 0 has no effect. 1 - Writing 1 clears the transmit FIFO. The Frame Sync Length field specifies the length of the frame synchronization signal, when a long frame sync signal (FSS = 1) and a 16-bit data word length (DWL = 1) are used. If an 8-bit data word length is used, long frame syncs are always 6 bit clocks in length. FSL 00 01 10 11 Frame Sync Length 13 bit clocks 14 bit clocks 15 bit clocks 16 bit clocks
IFS
The Inverted Frame Sync bit controls the polarity of the frame sync signal. 0 - Active-high frame sync signal. 1 - Active-low frame sync signal.
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IOM2
AAIEN
CLKEN
The IOM-2 Mode bit selects the normal PCM interface mode or a special IOM-2 mode used to connect to external ISDN controller devices. The AAI can only operate as a slave in the IOM-2 mode, i.e. the bit clock and frame sync signals are provided by the ISDN controller. If the IOM2 bit is clear, the AAI operates in the normal PCM interface mode used to connect to external PCM codecs and other PCM audio devices. 0 - IOM-2 mode disabled. 1 - IOM-2 mode enabled. The AAI Enable bit controls whether the Advanced Audio Interface is enabled. All AAI registers provide read/write access while (CLKEN = 1) AAIEN is clear. The AAIEN bit is clear after reset. 0 - AAI module disabled. 1 - AAI module enabled. The Clock Enable bit controls whether the Advanced Audio Interface clock is enabled. The CLKEN bit must be set to allow access to any AAI register. It must also be set before any other bit of the AGCR can be set. The CLKEN bit is clear after reset. 0 - AAI module clock disabled. 1 - AAI module clock enabled. Audio Interrupt Status and Control Register (AISCR)
TXIE
TXEIE
RXIP
RXEIP
18.7.6
The ASCR register is used to specify the source and the conditions, when the audio interface interrupt is asserted to TXIP the Interrupt Control Unit. It also holds the interrupt pending bits and the corresponding interrupt clear bits for each audio interface interrupt source. The CPU bus master has read/ write access to the ASCR register. After reset, this register is clear. 7 6 5 4 3 2 1 0 TXEIP
TXEIP TXIP RXEIP RXIP TXEIE TXIE RXEIE RXIE
15 Reserved
12
11
10
9
8 RXIC
TXEIC TXIC RXEIC RXIC
RXIE
RXEIE
The Receive Interrupt Enable bit controls whether receive interrupts are generated. If the RXIE bit is clear, no receive interrupt will RXEIC be generated. 0 - Receive interrupt disabled. 1 - Receive interrupt enabled. The Receive Error Interrupt Enable bit con- TXIC trols whether receive error interrupts are generated. Setting this bit enables a receive error interrupt, when the Receive Buffer Overrun (RXOR) bit is set. If the RXEIE bit is clear, no TXEIC receive error interrupt will be generated. 0 - Receive error interrupt disabled. 1 - Receive error interrupt enabled.
The Transmit Interrupt Enable bit controls whether transmit interrupts are generated. Setting this bit enables a transmit interrupt, when the Transmit Buffer Almost Empty (TXAE) bit is set. If the TXIE bit is clear, no interrupt will be generated. 0 - Transmit interrupt disabled. 1 - Transmit interrupt enabled. The Transmit Error Interrupt Enable bit controls whether transmit error interrupts are generated. Setting this bit to 1 enables a transmit error interrupt, when the Transmit Buffer Underrun (TXUR) bit is set. If the TXEIE bit is clear, no transmit error interrupt will be generated. 0 - Transmit error interrupt disabled. 1 - Transmit error interrupt enabled. The Receive Interrupt Pending bit indicates that a receive interrupt is currently pending. The RXIP bit is cleared by writing a 1 to the RXIC bit. The RXIP bit provides read-only access. 0 - No receive interrupt pending. 1 - Receive interrupt pending. The Receive Error Interrupt Pending bit indicates that a receive error interrupt is currently pending. The RXEIP bit is cleared by writing a 1 to the RXEIC bit. The RXEIP bit provides read-only access. 0 - No receive error interrupt pending. 1 - Receive error interrupt pending. The Transmit Interrupt Pending bit indicates that a transmit interrupt is currently pending. The TXIP bit is cleared by writing a 1 to the TXIC bit. The TXIP bit provides read-only access. 0 - No transmit interrupt pending. 1 - Transmit interrupt pending. Transmit Error Interrupt Pending. This bit indicates that a transmit error interrupt is currently pending. The TXEIP bit is cleared by software by writing a 1 to the TXEIC bit. The TXEIP bit provides read-only access. 0 - No transmit error interrupt pending. 1 - Transmit error interrupt pending. The Receive Interrupt Clear bit is used to clear the RXIP bit. 0 - Writing a 0 to the RXIC bit is ignored. 1 - Writing a 1 clears the RXIP bit. The Receive Error Interrupt Clear bit is used to clear the RXEIP bit. 0 - Writing a 0 to the RXEIC bit is ignored. 1 - Writing a 1 clears the RXEIP bit. The Transmit Interrupt Clear bit is used to clear the TXIP bit. 0 - Writing a 0 to the TXIC bit is ignored. 1 - Writing a 1 clears the TXIP bit. The Transmit Error Interrupt Clear bit is used to clear the TXEIP bit. 0 - Writing a 0 to the TXEIC bit is ignored. 1 - Writing a 1 clears the TXEIP bit.
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18.7.7
Audio Receive Status and Control Register (ARSCR)
The following table shows the slot assignment scheme. RXSA Bit RXSA0 RXSA1 RXSA2 RXSA3 Slots Enabled 0 1 2 3
The ARSCR register is used to control the operation of the receiver path of the audio interface. It also holds bits which report the current status of the receive FIFO. The CPU bus master has read/write access to the ASCR register. At reset, this register is loaded with 0004h. 7 RXSA 4 3 RXO 2 RXE 1 0
RXF RXAF
15 RXFWL
12
11 RXDSA
8 RXDSA
RXAF
RXF
RXE
RXO
RXSA
The Receive Buffer Almost Full bit is set when the number of data bytes/words in the receive buffer is equal to the specified warning limit. 0 - Receive FIFO below warning limit. 1 - Receive FIFO is almost full. The Receive Buffer Full bit is set when the receive buffer is full. The RXF bit is set when the RWP is equal to the RRP and the last access was a write to the FIFO. 0 - Receive FIFO is not full. 1 - Receive FIFO full. The Receive Buffer Empty bit is set when the the RRP is equal to the RWP and the last access to the FIFO was a read operation (read from ARDR). 0 - Receive FIFO is not empty. 1 - Receive FIFO is empty. The Receive Overflow bit indicates that a receive shift register has overrun. This occurs, when a completed data word has been shifted RXFWL into ARSR, while the receive FIFO was already full (the RXF bit was set). In this case, the new data in ARSR will not be copied into the FIFO and the RWP will not be incremented. Also, no receive interrupt and DMA request will generated (even if enabled). 0 - No overflow has occurred. 1 - Overflow has occurred. The Receive Slot Assignment field specifies which slots are recognized by the receiver of the audio interface. Multiple slots may be enabled. If the frame consists of less than 4 slots, the RXSA bits for unused slots are ignored. For example, if a frame only consists of 2 slots, RXSA bits 2 and 3 are ignored.
After reset the RXSA field is clear, so software must load the correct slot assignment. The Receive DMA Slot Assignment field specifies which slots (audio channels) are supported by DMA. If the RXDSA bit is set for an assigned slot n (RXSAn = 1), the data received within this slot will not be transferred into the receive FIFO, but will instead be written into the corresponding Receive DMA data register (ARDRn). A DMA request n is asserted, when the ARDRn is full and if the RMA bit n is set. If the RXSD bit for a slot is clear, the RXDSA bit is ignored. The following table shows the DMA slot assignment scheme. RXDSA Bit RXDSA0 RXDSA1 RXDSA2 RXDSA3 Slots Enabled for DMA 0 1 2 3
The Receive FIFO Warning Level field specifies when a receive interrupt is asserted. A receive interrupt is asserted, when the number of bytes/words in the receive FIFO is greater than the warning level value. An RXFWL value of 0 means that a receive interrupt is asserted if one or more bytes/words are in the RX FIFO. After reset, the RXFWL bit is clear.
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18.7.8
Audio Transmit Status and Control Register (ATSCR) TXSA Bit TXSA0 TXSA1 TXSA2 Slots Enabled 0 1 2 3
The ASCR register controls the basic operation of the interface. It also holds bits which report the current status of the audio communication. The CPU bus master has read/write access to the ASCR register. At reset, this register is loaded with F003h. 7 TXSA 4 3 TXU 2 TXF 1 0
TXSA3
TXE TXAE After reset, the TXSA field is clear, so software must load the correct slot assignment. The Transmit DMA Slot Assignment field specifies which slots (audio channels) are supported by DMA. If the TXDSA bit is set for an assigned slot n (TXSAn = 1), the data to be transmitted within this slot will not be read from the transmit FIFO, but will instead be read from the corresponding Transmit DMA data register (ATDRn). A DMA request n is asserted when the ATDRn is empty. If the TSA bit for a slot is clear, the TXDSA bit is ignored. The following table shows the DMA slot assignment scheme. TXDSA Bit TXDSA0 TXDSA1 TXDSA2 TXDSA3 Slots Enabled for DMA 0 1 2 3
15 TXFWL
12
11 TXDSA
8
TXDSA
TXAE
TXE
TXF
TXU
TXSA
The Transmit FIFO Almost Empty bit is set when the number of data bytes/words in transmit buffer is equal to the specified warning limit. 0 - Transmit FIFO above warning limit. 1 - Transmit FIFO at or below warning limit. The Transmit FIFO Empty bit is set when the transmit buffer is empty. The TXE bit is set to one every time the TRP is equal to the TWP and the last access to the FIFO was read operation (into ATSR). 0 - Transmit FIFO not empty. 1 - Transmit FIFO empty. The Transmit FIFO Full bit is set when the TWP is equal to the TRP and the last access to the FIFO was write operation (write to ATDR). 0 - Transmit FIFO not full. 1 - Transmit FIFO full. The Transmit Underflow bit indicates that the TFWL transmit shift register (ATSR) has underrun. This occurs when the transmit FIFO was already empty and a complete data word has been transferred. In this case, the TRP will be decremented by 1 and the previous data will be retransmitted. No transmit interrupt and no DMA request will be generated (even if enabled). 0 - Transmit underrun occurred. 1 - Transmit underrun did not occur. The Transmit Slot Assignment field specifies during which slots the transmitter is active and drives data through the STD pin. The STD pin is in high impedance state during all other slots. If the frame consists of less than 4 slots, the TXSA bits for unused slots are ignored. For example, if a frame only consists of 2 slots, TXSA bits 2 and 3 are ignored. The following table shows the slot assignment scheme.
The Transmit FIFO Warning Level field specifies when a transmit interrupt is asserted. A transmit interrupt is asserted when the number of bytes or words in the transmit FIFO is equal or less than the warning level value. A TXFWL value of Fh means that a transmit interrupt is asserted if one or more bytes or words are available in the transmit FIFO. At reset, the TXFWL field is loaded with Fh.
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18.7.9
Audio Clock Control Register (ACCR)
The ACCR register is used to control the bit timing of the audio interface. After reset, this register is clear. 7 FCPRS 1 0 CSS
ignored. The following table shows the receive DMA request scheme. RMD 0000 0001 0010 DMA Request Condition None ARDR0 full ARDR1 full ARDR0 full or ARDR1 full Not supported on CP3CN23
15 BCPRS
8
0011 x1xx
CSS
FCPRS
BCPRS
The Clock Source Select bit selects one out of two possible clock sources for the audio interTMD face. After reset, the CSS bit is clear. 0 - The Auxiliary Clock 1 is used to clock the Audio Interface. 1 - The 48-MHz clock is used to clock the Audio Interface. The Frame Clock Prescaler is used to divide the bit clock to generate the frame clock for the receive and transmit operations. The bit clock is divided by (FCPRS + 1). After reset, the FCPRS field is clear. The maximum allowed bit clock rate to achieve an 8 kHz frame clock is 1024 kHz. This value must be set correctly even if the frame sync is generated externally. The Bit Clock Prescaler is used to divide the audio interface clock (selected by the CSS bit) to generate the bit clock for the receive and transmit operations. The audio interface input clock is divided by (BCPRS + 1). After reset, the BCPRS[7:0] bits are clear.
1xxx
The Transmit Master DMA field specifies which slots (audio channels) are supported by DMA, i.e. when a DMA request is asserted to the DMA controller. If the TMD bit is set for an assigned slot n (TXDSAn = 1), a DMA request n is asserted, when the ATDRn register is empty. If the TXDSA bit for a slot is clear, the TMD bit is ignored. The following table shows the transmit DMA request scheme. TMD 0000 0001 0010 0011 x1xx 1xxx DMA Request Condition None ATDR0 empty ATDR1 empty ATDR0 empty or ATDR1 empty Not supported on CP3CN23
18.7.10 Audio DMA Control Register (ADMACR) The ADMACR register is used to control the DMA support of the audio interface. In addition, it is used to configure the automatic transmission of the audio control bits. After reset, this register is clear. 7 TMD 4 3 RMD 0 ACD
ACO
15 Reserved
13
12 ACO
11
10 ACD
8
The Audio Control Data field is used to fill the remaining bits of a 16-bit slot if only 13, 14, or 15 bits of PCM audio data are transmitted. The Audio Control Output field controls the number of control bits appended to the PCM data word. 00 - No Audio Control bits are appended. 01 - Append ACD0. 10 - Append ACD1:0. 11 - Append ACD2:0.
RMD
The Receive Master DMA field specify which slots (audio channels) are supported by DMA, i.e. when a DMA request is asserted to the DMA controller. If the RMDn bit is set for an assigned slot n (RXDSAn = 1), a DMA request n is asserted, when the ARDRn is full. If the RXDSAn bit for a slot is clear, the RMDn bit is
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19.0 CVSD/PCM Conversion Module
The CVSD/PCM module performs conversion between CVSD data and PCM data, in which the CVSD encoding is as defined in the Bluetooth specification and the PCM encoding may be 8-bit -Law, 8-bit A-Law, or 13-bit to 16-bit Linear. The CVSD conversion module operates at a fixed rate of 125 s (8 kHz) per PCM sample. On the CVSD side, there
2 MHz Clock Input
is a read and a write FIFO allowing up to 8 words of data to be read or written at the same time. On the PCM side, there is a double-buffered register requiring data to be read and written every 125 s. The intended use is to move CVSD data into the module with a CVSD interrupt handler, and to move PCM data with DMA. Figure 57 shows a block diagram of the CVSD to PCM module.
Interrupt
DMA
16-Bit 8 kHz 16-Bit u/A-Law 16-Bit 8 kHz Filter Engine 16-Bit u/A-Law 64 kHz 64 kHz CVSD Encoder
1-Bit 64 kHz 16-Bit Shift Reg
1-Bit 64 kHz CVSD Decoder 16-Bit Shift Reg
Peripheral Bus
DS058
Figure 57. CVSD/PCM Converter Block Diagram
19.1
Inside the module, a filter engine receives the 8 kHz stream of 16-bit samples and interpolates to generate a 64 kHz The Aux2 clock (generated by the Clock module described stream of 16-bit samples. This goes into a CVSD encoder in Section 11.9) must be configured, because it drives the which converts the data into a single-bit delta stream using CVSD module. Software must set its prescaler to provide a the CVSD parameters as defined by the Bluetooth specifi2 MHz input clock based upon the System Clock (usually cation. There is a similar path that reverses this process 12 MHz). This is done by writing an appropriate divisor to converting the CVSD 64 kHz bit stream into a 64 kHz 16-bit the ACDIV2 field of the PRSAC register. Software must also data stream. The filter engine then decimates this stream enable the Aux2 clock by setting the ACE2 bit within the into an 8 kHz, 16-bit data stream. CRCTRL register. For example: PRSAC &= 0x0f; // Set Aux2 prescaler to generate // 2 MHz (Fsys = 12 MHz) PRSAC |= 0x50; CRCTRL |= ACE2; // Enable Aux2 clk The module converts between PCM data and CVSD data at a fixed rate of 8 kHz per PCM sample. Due to compression, the data rate on the CVSD side is only 4 kHz per CVSD sample.
OPERATION
19.2
PCM CONVERSIONS
If PCM interrupts are enabled (PCMINT is set) every 125 s (8 kHz) an interrupt will occur and the interrupt handler can operate on some or all of the four audio streams CVSD in, CVSD out, PCM in, and PCM out. Alternatively, a DMA request is issued every 125 s and the DMA controller is used If a conversion is performed between linear and -Law log to move the PCM data between the CVSD/PCM module PCM data, the linear PCM data are treated in the leftand the audio interface. aligned 14-bit linear data format with the two LSBs unused. If CVSD interrupts are enabled, an interrupt is issued when If a conversion is performed between linear and A-Law log either one of the CVSD FIFOs is almost empty or almost full. PCM data, the linear PCM data are treated in the leftOn the PCM data side there is double buffering, and on the aligned 13-bit linear data format with the three LSBs unCVSD side there is an eight word (8 x 16-bit) FIFO for the used. read and write paths.
During conversion between CVSD and PCM, any PCM format changes are done automatically depending on whether the PCM data is -Law, A-Law, or Linear. In addition to this, a separate function can be used to convert between the various PCM formats as required. Conversion is performed by setting up the control bit CVCTL1.PCMCONV to define the conversion and then writing to the LOGIN and LINEARIN registers and reading from the LOGOUT and LINEAROUT registers. There is no delay in the conversion operation and it does not have to operate at a fixed rate. It will only convert between -Law/A-Law and linear, not directly between Law and A-Law. (This could easily be achieved by converting between -Law and linear and between linear and ALaw.)
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If the module is only used for PCM conversions, the CVSD been transferred to the audio interface, it will be overwritten clock can be disabled by clearing the CVSD Clock Enable with the new PCM sample. bit (CLKEN) in the control register. If there are only three unread words left, the CVSD In Nearly Empty bit (CVNE) is set and, if enabled (CVSDINT = 1), an 19.3 CVSD CONVERSION interrupt request is generated. The CVSD/PCM converter module transforms either 8-bit logarithmic or 13- to 16-bit linear PCM samples at a fixed If the CVSD In FIFO is empty, the CVSD In Empty bit (CVE) rate of 8 ksps. The CVSD to PCM conversion format must is set and, if enabled (CVSDERRINT = 1), an interrupt rebe specified by the CVSDCONV control bits in the CVSD quest is generated. If the converter core reads from an already empty CVSD In FIFO, the FIFO automatically returns Control register (CVCTRL). a checkerboard pattern to guarantee a minimum level of disThe CVSD algorithm is designed for 2's complement 16-bit tortion of the audio stream. data and is tuned for best performance with typical voice daINTERRUPT GENERATION ta. Mild distortion will occur for peak signals greater than -6 19.6 dB. The Bluetooth CVSD standard is designed for best per- An interrupt is generated in any of the following cases: formace with typical voice signals: nominaly -6dB with occaWhen a new PCM sample has been written into the sional peaks to 0dB rather than full-scale inputs. Distortion PCMOUT register and the CVCTRL.PCMINT bit is set. of signals greater than -6dB is not considered detrimental to When a new PCM sample has been read from the subjective quality tests for voice-band applications and alPCMIN register and the CVCTRL.PCMINT bit is set. lows for greater clarity for signals below -6dB. The gain of When the CVSD In FIFO is nearly empty the input device should be tuned with this in mind. (CVSTAT.CVNE = 1) and the CVCTRL.CVSDINT bit is If required, the RESOLUTION field of the CVCTRL register set. can be used to optimize the level of the 16-bit linear input When the CVSD Out FIFO is nearly full data by providing attenuations (right-shifts with sign exten(CVSTAT.CVNF = 1) and the CVCTRL.CVSDINT bit is tion) of 1, 2, or 3 bits. set. When the CVSD In FIFO is empty (CVSTAT.CVE = 1) Log data is always 8 bit, but to perform the CVSD converand the CVCTRL.CVSDERRINT bit is set. sion, the log data is first converted to 16-bit 2's complement When the CVSD Out FIFO is full (CVSTAT.CVF = 1) and linear data. A-law and u-law conversion can also slightly afthe CVCTRL.CVSDERRINT bit is set. fect the optimum gain of the input data. The CVCTRL.RESOLUTION field can be used to attenuate the data if required. Both the CVSD In and CVSD Out FIFOs have a size of If the resolution is not set properly, the audio signal may be 8 x 16 bit (8 words). The warning limits for the two FIFOs is set at 5 words. (The CVSD In FIFO interrupt will occur when clipped or have reduced attenuation. there are 3 words left in the FIFO, and the CVSD Out FIFO 19.4 PCM TO CVSD CONVERSION interrupt will occur when there are 3 or less empty words left The converter core reads out the double-buffered PCMIN in the FIFO.) The limit is set to 5 words because Bluetooth register every 125 s and writes a new 16-bit CVSD data audio data is transferred in packages composed of 10 or stream into the CVSD Out FIFO every 250 s. If the PCMIN multiples of 10 bytes. buffer has not been updated with a new PCM sample beDMA SUPPORT tween two reads from the CVSD core, the old PCM data is 19.7 used again to maintain a fixed conversion rate. Once a new The CVSD module can operate with any of four DMA chan16-bit CVSD data stream has been calculated, it is copied nels. Four DMA channels are required for processor independent operation. Both receive and transmit for CVSD into the 8 x 16-bit wide CVSD Out FIFO. If there are only three empty words (16-bit) left in the FIFO, data and PCM data can be enabled individually. The CVSD/ the nearly full bit (CVNF) is set, and, if enabled PCM module asserts a DMA request to the on-chip DMA controller under the following conditions: (CVSDINT = 1), an interrupt request is asserted. If the CVSD Out FIFO is full, the full bit (CVF) is set, and, if enabled (CVSDERRINT = 1), an interrupt request is asserted. In this case, the CVSD Out FIFO remains unchanged. Within the interrupt handler, the CPU can read out the new CVSD data. If the CPU reads from an already empty CVSD Out FIFO, a lockup of the FIFO logic may occur which persists until the next reset. Software must check the CVOUTST field of the CVSTAT register to read the number of valid words in the FIFO. Software must not use the CVNF bit as an indication of the number of valid words in the FIFO. The DMAPO bit is set and the PCMOUT register is full, because it has been updated by the converter core with a new PCM sample. (The DMA controller can read out one PCM data word from the PCMOUT register.) The DMAPI bit is set and the PCMIN register is empty, because it has been read by the converter core. (The DMA controller can write one new PCM data word into the PCMIN register.) The DMACO bit is set and a new 16-bit CVSD data stream has been copied into the CVSD Out FIFO. (The DMA controller can read out one 16-bit CVSD data word from the CVSD Out FIFO.) The DMACI bit is set and a 16-bit CVSD data stream has been read from the CVSD In FIFO. (The DMA controller can write one new 16-bit CVSD data word into the CVSD In FIFO.)
19.5
CVSD TO PCM CONVERSION
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The CVSD/PCM module only supports indirect DMA transfers. Therefore, transferring PCM data between the CVSD/ PCM module and another on-chip module requires two bus cycles. The trigger for DMA may also trigger an interrupt if the corresponding enable bits in the CVCTRL register is set. Therefore care must be taken when setting the desired interrupt and DMA enable bits. The following conditions must be avoided: Setting the PCMINT bit and either of the DMAPO or DMAPI bits. Setting the CVSDINT bit and either of the DMACO or DMACI bits.
Table 58 CVSD/PCM Registers Name LINEAROUT CVCTRL CVSTAT 19.9.1 Address FF FC2Eh FF FC30h FF FC32h Description Linear PCM Data Output Register CVSD Control Register CVSD Status Register
CVSD Data Input Register (CVSDIN)
19.8
FREEZE
The CVSD/PCM module provides support for an In-SystemEmulator by means of a special FREEZE input. While FREEZE is asserted the module will exhibit the following behavior: CVSD In FIFO will not have data removed by the converter core. CVSD Out FIFO will not have data added by the converter core. PCM Out buffer will not be updated by the converter core. The Clear-on-Read function of the following status bits in the CVSTAT register is disabled: PCMINT CVE CVF
The CVSDIN register is a 16-bit wide, write-only register. It is used to write CVSD data into the CVSD to PCM converter FIFO. The FIFO is 8 words deep. The CVSDIN bit 15 represents the CVSD data bit at t = t0, CVSDIN bit 0 represents the CVSD data bit at t = t0 - 250 ms. 15 CVSDIN 0
19.9.2
CVSD Data Output Register (CVSDOUT)
The CVSDOUT register is a 16-bit wide read-only register. It is used to read the CVSD data from the PCM to CVSD converter. The FIFO is 8 words deep. Reading the CVSDOUT register after reset returns undefined data. 15 CVSDOUT 0
19.9
CVSD/PCM CONVERTER REGISTERS
Table 58 CVSD/PCM Registers Name Address FF FC20h FF FC22h FF FC24h FF FC26h FF FC28h FF FC2Ah FF FC2Ch Description CVSD Data Input Register CVSD Data Output Register PCM Data Input Register PCM Data Output Register Logarithmic PCM Data Input Register Logarithmic PCM Data Output Register Linear PCM Data Input Register 19.9.4 19.9.3
Table 58 lists the CVSD/PCM registers. PCM Data Input Register (PCMIN)
CVSDIN CVSDOUT PCMIN PCMOUT LOGIN LOGOUT LINEARIN
The PCMIN register is a 16-bit wide write-only register. It is used to write PCM data to the PCM to CVSD converter via the peripheral bus. It is double-buffered, providing a 125 s period for an interrupt or DMA request to respond. 15 PCMIN 0
PCM Data Output Register (PCMOUT)
The PCMOUT register is a 16-bit wide read-only register. It is used to read PCM data from the CVSD to PCM converter. It is double-buffered, providing a 125 s period for an interrupt or DMA request to respond. After reset the PCMOUT register is clear. 15 PCMOUT 0
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19.9.5
Logarithmic PCM Data Input Register (LOGIN)
The LOGIN register is an 8-bit wide write-only register. It is used to receive 8-bit logarithmic PCM data from the peripheral bus and convert it into 13-bit linear PCM data. 7 LOGIN 0
19.9.6
Logarithmic PCM Data Output Register (LOGOUT)
The LOGOUT register is an 8-bit wide read-only register. It holds logarithmic PCM data that has been converted from linear PCM data. After reset, the LOGOUT register is clear. 7 LOGOUT 0
19.9.7
Linear PCM Data Input Register (LINEARIN)
The LINEARIN register is a 16-bit wide write-only register. The data is left-aligned. When converting to A-law, bits 2:0 are ignored. When converting to -law, bits 1:0 are ignored. 15 LINEARIN 0
19.9.8
Linear PCM Data Output Register (LINEAROUT)
The LINEAROUT register is a 16-bit wide read-only register. The data is left-aligned. When converting from A-law, bits 2:0 are clear. When converting from -law, bits 1:0 are clear. After reset, this register is clear. 15 LINEAROUT 0
19.9.9
CVSD Control Register (CVCTRL)
The CVCTRL register is a 16-bit wide, read/write register that controls the mode of operation and of the module's interrupts. At reset, all implemented bits are cleared. 7 DMA PO 6 DMA CI 5 4 3 2 1 0
CVSD DMA CVSD PCM ERRCO INT INT INT
CLK CVEN EN
15 14
13
12
11
10
9
8
Res. RESOLUTION PCMCONV CVSDCONV DMAPI
The Module Enable bit enables or disables the CVSD conversion module interface. When the bit is set, the interface is enabled which allows read and write operations to the rest of the module. When the bit is clear, the module is disabled. When the module is disabled the status register CVSTAT will be cleared to its reset state. 0 - CVSD module enabled. 1 - CVSD module disabled. CLKEN The CVSD Clock Enable bit enables the 2MHz clock to the filter engine and CVSD encoders and decoders. 0 - CVSD module clock disabled. 1 - CVSD module clock enabled. PCMINT The PCM Interrupt Enable bit controls generation of the PCM interrupt. If set, this bit enables the PCM interrupt. If the PCMINT bit is clear, the PCM interrupt is disabled. After reset, this bit is clear. 0 - PCM interrupt disabled. 1 - PCM interrupt enabled. CVSDINT The CVSD FIFO Interrupt Enable bit controls generation of the CVSD interrupt. If set, this bit enables the CVSD interrupt that occurs if the CVSD In FIFO is nearly empty or the CVSD Out FIFO is nearly full. If the CVSDINT bit is clear, the CVSD nearly full/nearly empty interrupt is disabled. After reset, this bit is clear. 0 - CVSD interrupt disabled. 1 - CVSD interrupt enabled. CVSDERRINT The CVSD FIFO Error Interrupt Enable bit controls generation of the CVSD error interrupt. If set, this bit enables an interrupt to occur when the CVSD Out FIFO is full or the CVSD In FIFO is empty. If the CVSDERRORINT bit is clear, the CVSD full/empty interrupt is disabled. After reset, this bit is clear. 0 - CVSD error interrupt disabled. 1 - CVSD error interrupt enabled. DMACO The DMA Enable for CVSD Out bit enables hardware DMA control for reading CVSD data from the CVSD Out FIFO. If clear, DMA support is disabled. After reset, this bit is clear. 0 - CVSD output DMA disabled. 1 - CVSD output DMA enabled. DMACI The DMA Enable for CVSD In bit enables hardware DMA control for writing CVSD data into the CVSD In FIFO. If clear, DMA support is disabled. After reset, this bit is clear. 0 - CVSD input DMA disabled. 1 - CVSD input DMA enabled. DMAPO The DMA Enable for PCM Out bit enables hardware DMA control for reading PCM data from the PCMOUT register. If clear, DMA support is disabled. After reset, this bit is clear. 0 - PCM output DMA disabled. 1 - PCM output DMA enabled.
CVEN
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The DMA Enable for PCM In bit enables hard- CVNF ware DMA control for writing PCM data into the PCMIN register. If cleared, DMA support is disabled. After reset, this bit is clear. 0 - PCM input DMA disabled. 1 - PCM input DMA enabled. CVSDCONV The CVSD to PCM Conversion Format field specifies the PCM format for CVSD/PCM conversions. After reset, this field is clear. 00 - CVSD <-> 8-bit -Law PCM. 01 - CVSD <-> 8-bit A-Law PCM. 10 - CVSD <-> Linear PCM. 11 - Reserved. PCMCONV The PCM to PCM Conversion Format bit selects the PCM format for PCM/PCM conversions. PCMINT 0 - Linear PCM <-> 8-bit -Law PCM 1 - Linear PCM <-> 8-bit A-Law PCM RESOLUTION The Linear PCM Resolution field specifies the attenuation of the PCM data for the linear PCM to CVSD conversions by right shifting and sign extending the data. This affects the log PCM data as well as the linear PCM data. The log data is converted to either left-justified CVE zero-stuffed 13-bit (A-law) or 14-bit (u-law). The RESOLUTION field can be used to compensate for any change in average levels resulting from this conversion. After reset, these two bits are clear. 00 - No shift. 01 - 1-bit attentuation. 10 - 2-bit attentuation. 11 - 3-bit attentuation. 19.9.10 CVSD Status Register (CVSTAT) The CVSTAT register is a 16-bit wide, read-only register that holds the status information of the CVSD/PCM module. At reset, and if the CVCTL1.CVEN bit is clear, all implemented bits are cleared. 7 CVINST 5 4 CVF 3 2 1 0 CVF
DMAPI
CVE PCMINT CVNF CVNE
15 Reserved
11
10 CVOUTST
8 CVINST
CVNE
The CVSD In FIFO Nearly Empty bit indicates when only three CVSD data words are left in the CVSD In FIFO, so new CVSD data should be written into the CVSD In FIFO. If the CVSDINT bit is set, an interrupt will be asserted CVOUTST when the CVNE bit is set. If the DMACI bit is set, a DMA request will be asserted when this bit is set. The CVNE bit is cleared when the CVSTAT register is read. 0 - CVSD In FIFO is not nearly empty. 1 - CVSD In FIFO is nearly empty.
The CVSD Out FIFO Nearly Full bit indicates when only three empty word locations are left in the CVSD Out FIFO, so the CVSD Out FIFO should be read. If the CVSDINT bit is set, an interrupt will be asserted when the CVNF bit is set. If the DMACO bit is set, a DMA request will be asserted when this bit is set. Software must not rely on the CVNF bit as an indicator of the number of valid words in the FIFO. Software must check the CVOUTST field to read the number of valid words in the FIFO. The CVNF bit is cleared when the CVSTAT register is read. 0 - CVSD Out FIFO is not nearly full. 1 - CVSD Out FIFO is nearly full. The PCM Interrupt bit set indicates that the PCMOUT register is full and needs to be read or the PCMIN register is empty and needs to be loaded with new PCM data. The PCMINT bit is cleared when the CVSTAT register is read, unless the device is in FREEZE mode. 0 - PCM does not require service. 1 - PCM requires loading or unloading. The CVSD In FIFO Empty bit indicates when the CVSD In FIFO has been read by the CVSD converter while the FIFO was already empty. If the CVSDERRORINT bit is set, an interrupt will be asserted when the CVE bit is set. The CVE bit is cleared when the CVSTAT register is read, unless the device is in FREEZE mode. 0 - CVSD In FIFO has not been read while empty. 1 - CVSD In FIFO has been read while empty. The CVSD Out FIFO Full bit set indicates whether the CVSD Out FIFO has been written by the CVSD converter while the FIFO was already full. If the CVSDERRORINT bit is set, an interrupt will be asserted when the CVF bit is set. The CVF bit is cleared when the CVSTAT register is read, unless the device is in FREEZE mode. 0 - CVSD Out FIFO has not been written while full. 1 - CVSD Out FIFO has been written while full. The CVSD In FIFO Status field reports the current number of empty 16-bit word locations in the CVSD In FIFO. When the FIFO is empty, the CVINST field will read as 111b. When the FIFO holds 7 or 8 words of data, the CVINST field will read as 000b. CVSD Out FIFO Status field reports the current number of valid 16-bit CVSD data words in the CVSD Out FIFO. When the FIFO is empty, the CVOUTST field will read as 000b. When the FIFO holds 7 or 8 words of data, the CVOUTST field will read as 111b.
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20.0 UART Modules
The CP3CN23 provides four UART modules. Each UART module is a full-duplex Universal Asynchronous Receiver/ Transmitter that supports a wide range of software-programmable baud rates and data formats. It handles automatic parity generation and several error detection schemes. All UART modules offer the following features: Full-duplex double-buffered receiver/transmitter Asynchronous operation Programmable baud rate Programmable framing formats: 7, 8, or 9 data bits; even, odd, or no parity; one or two stop bits (mark or space) Hardware parity generation for data transmission and parity check for data reception Interrupts on "transmit ready" and "receive ready" conditions, separately enabled Software-controlled break transmission and detection Internal diagnostic capability Automatic detection of parity, framing, and overrun errors One module, UART0, offers the following additional features: Synchronous operation using the CKX external clock pin Hardware flow control (CTS and RTS signals) DMA capability mode of operation, clock source, and type of parity used. The error detection circuit generates parity bits and checks for parity, framing, and overrun errors. The Flow Control Logic block provides the capability for hardware handshaking between the UART and a peripheral device. When the peripheral device needs to stop the flow of data from the UART, it de-asserts the clear-to-send (CTS) signal which causes the UART to pause after sending the current frame (if any). The UART asserts the ready-to-send (RTS) signal to the peripheral when it is ready to send a character.
20.2
UART OPERATION
The UART has two basic modes of operation: synchronous and asynchronous. Synchronous mode is only supported for the UART0 module. In addition, there are two specialpurpose modes, called attention and diagnostic. This section describes the operating modes of the UART. 20.2.1 Asynchronous Mode
The asynchronous mode of the UART enables the device to communicate with other devices using just two communication signals: transmit and receive.
In asynchronous mode, the transmit shift register (TSFT) and the transmit buffer (UnTBUF) double-buffer the data for transmission. To transmit a character, a data byte is loaded 20.1 FUNCTIONAL OVERVIEW in the UnTBUF register. The data is then transferred to the Figure 58 is a block diagram of the UART module showing TSFT register. While the TSFT register is shifting out the the basic functional units in the UART: current character (LSB first) on the TXD pin, the UnTBUF register is loaded by software with the next byte to be transTransmitter mitted. When TSFT finishes transmission of the last stop bit Receiver of the current frame, the contents of UnTBUF are transBaud Rate Generator ferred to the TSFT register and the Transmit Buffer Empty Control and Error Detection bit (UTBE) is set. The UTBE bit is automatically cleared by The Transmitter block consists of an 8-bit transmit shift regthe UART when software loads a new character into the ister and an 8-bit transmit buffer. Data bytes are loaded in UnTBUF register. During transmission, the UXMIP bit is set parallel from the buffer into the shift register and then shifted high by the UART. This bit is reset only after the UART has out serially on the TXD pin. sent the last stop bit of the current character and the UnTThe Receiver block consists of an 8-bit receive shift register BUF register is empty. The UnTBUF register is a read/write and an 8-bit receive buffer. Data is received serially on the register. The TSFT register is not software accessible. RXD pin and shifted into the shift register. Once eight bits In asynchronous mode, the input frequency to the UART is have been received, the contents of the shift register are 16 times the baud rate. In other words, there are 16 clock transferred in parallel to the receive buffer. cycles per bit time. In asynchronous mode, the baud rate The Transmitter and Receiver blocks both contain exten- generator is always the UART clock source. sions for 9-bit data transfers, as required by the 9-bit and The receive shift register (RSFT) and the receive buffer (Unloopback operating modes. RBUF) double buffer the data being received. The UART reThe Baud Rate Generator generates the clock for the syn- ceiver continuously monitors the signal on the RXD pin for a chronous and asynchronous operating modes. It consists of low level to detect the beginning of a start bit. On sensing two registers and a two-stage counter. The registers are this low level, the UART waits for seven input clock cycles used to specify a prescaler value and a baud rate divisor. and samples again three times. If all three samples still inThe first stage of the counter divides the UART clock based dicate a valid low, then the receiver considers this to be a on the value of the programmed prescaler to create a slower valid start bit, and the remaining bits in the character frame clock. The second stage of the counter creates the baud are each sampled three times, around the mid-bit position. rate clock by dividing the output of the first stage based on For any bit following the start bit, the logic value is found by the programmed baud rate divisor. majority voting, i.e. the two samples with the same value deThe Control and Error Detection block contains the UART fine the value of the data bit. Figure 59 illustrates the procontrol registers, control logic, error detection circuit, parity cess of start bit detection and bit sampling. generator/checker, and interrupt generation logic. The control registers and control logic determine the data format, www.national.com 136
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Data bits are sensed by taking a majority vote of three samples latched near the midpoint of each baud (bit time). Normally, the position of the samples within the baud is determined automatically, but software can override the automatic selection by setting the USMD bit in the UnMDSL2 register and programming the UnSPOS register. Serial data input on the RXD pin is shifted into the RSFT register. On receiving the complete character, the contents
of the RSFT register are copied into the UnRBUF register and the Receive Buffer Full bit (URBF) is set. The URBF bit is automatically cleared when software reads the character from the URBUF register. The RSFT register is not software accessible.
Transmitter
TXD
Baud Clock RTS System Clock Flow Control Logic CTS Internal Bus Control and Error Detection
Baud Rate Generator
CKX
Parity Generator/Checker Baud Clock
Receiver
RXD
DS060
Figure 58.
UART Block Diagram
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
Sample STARTBIT
Sample DATA (LSB)
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
Sample DATABIT DS061
Figure 59.
UART Asynchronous Communication
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20.2.2
Synchronous Mode
20.2.3
Attention Mode
The synchronous mode of the UART enables the device to communicate with other devices using three communication signals: transmit, receive, and clock. In this mode, data bits are transferred synchronously with the UART clock signal. Data bits are transmitted on the rising edges and received on the falling edges of the clock signal, as shown in Figure 60. Data bytes are transmitted and received least significant bit (LSB) first.
The Attention mode is available for networking this device with other processors. This mode requires the 9-bit data format with no parity. The number of start bits and number of stop bits are programmable. In this mode, two types of 9-bit characters are sent on the network: address characters consisting of 8 address bits and a 1 in the ninth bit position and data characters consisting of 8 data bits and a 0 in the ninth bit position. While in Attention mode, the UART receiver monitors the communication flow but ignores all characters until an address character is received. On receiving an address character, the contents of the receive shift register are copied to the receive buffer. The URBF bit is set and an interrupt (if enabled) is generated. The UATN bit is automatically cleared, and the UART begins receiving all subsequent characters. Software must examine the contents of the URBUF register and respond by accepting the subsequent characters (by leaving the UATN bit clear) or waiting for the next address character (by setting the UATN bit again).
CKX
TDX
RDX
Sample Input DS062
Figure 60. UART Synchronous Communication In synchronous mode, the transmit shift register (TSFT) and the transmit buffer (UnTBUF) double-buffer the data for transmission. To transmit a character, a data byte is loaded in the UnTBUF register. The data is then transferred to the TSFT register. The TSFT register shifts out one bit of the current character, LSB first, on each rising edge of the clock. While the TSFT is shifting out the current character on the TXD pin, the UnTBUF register may be loaded by software with the next byte to be transmitted. When the TSFT finishes transmission of the last stop bit within the current frame, the contents of UnTBUF are transferred to the TSFT register and the Transmit Buffer Empty bit (UTBE) is set. The UTBE bit is automatically reset by the UART when software loads a new character into the UnTBUF register. During transmission, the UXMIP bit is set by the UART. This bit is cleared only after the UART has sent the last frame bit of the current character and the UnTBUF register is empty. The receive shift register (RSFT) and the receive buffer (URBUF) double-buffer the data being received. Serial data received on the RXD pin is shifted into the RSFT register on the first falling edge of the clock. Each subsequent falling edge of the clock causes an additional bit to be shifted into the RSFT register. The UART assumes a complete character has been received after the correct number of rising edges on CKX (based on the selected frame format) have been detected. On receiving a complete character, the contents of the RSFT register are copied into the UnRBUF register and the Receive Buffer Full bit (URBF) is set. The URBF bit is automatically cleared when software reads the character from the UnRBUF register.
The operation of the UART transmitter is not affected by the selection of this mode. The value of the ninth bit to be transmitted is programmed by setting or clearing the UXB9 bit in the UART Frame Select register. The value of the ninth bit received is read from URB9 in the UART Status Register. 20.2.4 Diagnostic Mode
The Diagnostic mode is available for testing of the UART. In this mode, the TXD and RXD pins are internally connected together, and data shifted out of the transmit shift register is immediately transferred to the receive shift register. This mode supports only the 9-bit data format with no parity. The number of start and stop bits is programmable. 20.2.5 Frame Format Selection
The format shown in Figure 61 consists of a start bit, seven data bits (excluding parity), and one or two stop bits. If parity bit generation is enabled by setting the UPEN bit, a parity bit is generated and transmitted following the seven data bits.
Start Bit
1
7-Bit Data
1S
1a
Start Bit
7-Bit Data
2S
1b
Start Bit
7-Bit Data
PA
1S
1c
Start Bit
7-Bit Data
PA
2S
DS063
Figure 61.
7-Bit Data Frame Options
The format shown in Figure 62 consists of one start bit, The transmitter and receiver may be clocked by either an eight data bits (excluding parity), and one or two stop bits. If external source provided to the CKX pin or the internal baud parity bit generation is enabled by setting the UPEN bit, a rate generator. In the latter case, the clock signal is placed on the CKX pin as an output.
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parity bit is generated and transmitted following the eight data bits.
Start Bit
Table 59 Prescaler Factors (Continued) Prescaler Select Prescaler Factor 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 14.5 15 15.5 16
2
8-Bit Data
1S
01011 01100
2a
Start Bit
8-Bit Data
2S
01101 01110
2b
Start Bit
8-Bit Data
PA
1S
01111 10000
2c
Start Bit
8-Bit Data
PA
2S DS064
10001 10010 10011 10100
Figure 62.
8-Bit Data Frame Options
The format shown in Figure 63 consists of one start bit, nine data bits, and one or two stop bits. This format also supports the UART attention feature. When operating in this format, all eight bits of UnTBUF and UnRBUF are used for data. The ninth data bit is transmitted and received using two bits in the control registers, called UXB9 and URB9. Parity is not generated or verified in this mode.
3 Start Bit 9-Bit Data 1S
10101 10110 10111 11000 11001 11010 11011
3a
Start Bit
9-Bit Data
2S
11100 11101
DS065
11110 11111
Figure 63. 9-bit Data Frame Options 20.2.6 Baud Rate Generator
The Baud Rate Generator creates the basic baud clock from the System Clock. The System Clock is passed through a two-stage divider chain consisting of a 5-bit baud rate prescaler (UnPSC) and an 11-bit baud rate divisor (UnDIV). The relationship between the 5-bit prescaler select (UnPSC) setting and the prescaler factors is shown in Table 59. Table 59 Prescaler Factors Prescaler Select 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 Prescaler Factor No clock 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5
A prescaler factor of zero corresponds to "no clock." The "no clock" condition is the UART power down mode, in which the UART clock is turned off to reduce power consumption. Software must select the "no clock" condition before entering a new baud rate. Otherwise, it could cause incorrect data to be received or transmitted. The UnPSR register must contain a value other than zero when an external clock is used at CKX. 20.2.7 Interrupts
The UART is capable of generating interrupts on: Receive Buffer Full Receive Error Transmit Buffer Empty
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Figure 64 shows a diagram of the interrupt sources and associated enable bits.
UEEI
UFE
UDOE
UERR RX Interrupt UERI
UPE
URBF
UETI
UTBE
TX Interrupt UEFCI
UDCTS
FC Interrupt DS066
Figure 64.
UART Interrupts 20.2.8 DMA Support
The interrupts can be individually enabled or disabled using the Enable Transmit Interrupt (UETI), Enable Receive Interrupt (UERI), and Enable Receive Error Interrupt (UEER) bits in the UnICTRL register.
A transmit interrupt is generated when both the UTBE and UETI bits are set. To remove this interrupt, software must ei- If transmit DMA is enabled (the UETD bit is set), the UART ther disable the interrupt by clearing the UETI bit or write to generates a DMA request when the UTBE bit changes state the UnTBUF register (which clears the UTBE bit). from clear to set. Enabling transmit DMA automatically disA receive interrupt is generated on these conditions: ables transmit interrupts, without regard to the state of the Both the URBF and UERI bits are set. To remove this in- UETI bit. terrupt, software must either disable the interrupt by clearing the UERI bit or read from the URBUF register (which clears the URBF bit). Both the UERR and the UEEI bits are set. To remove this interrupt, software must either disable the interrupt by clearing the UEEI bit or read the UnSTAT register (which clears the UERR bit). A flow control interrupt is generated when both the UDCTS and the UEFCI bits are set. To remove this interrupt, software must either disable the interrupt by clearing the UEFCI bit or reading the UnICTRL register (which clears the UDCTS bit). In addition to the dedicated inputs to the ICU for UART interrupts, the UART receive (RXD) and Clear To Send (CTS) signals are inputs to the MIWU (see Section 13.0), which can be programmed to generate edge-triggered interrupts. If receive DMA is enabled (the UERD bit is set), the UART generates a DMA request when the URBF bit changes state from clear to set. Enabling receive DMA automatically disables receive interrupts, without regard to the state of the UERI bit. However, receive error interrupts should be enabled (the UEEI bit is set) to allow detection of receive errors when DMA is used. 20.2.9 Break Generation and Detection
The UART module can operate with one or two DMA channels. Two DMA channels must be used for processor-independent full-duplex operation. Both receive and transmit DMA can be enabled simultaneously.
A line break is generated when the UBRK bit is set in the UnMDSL1 register. The TXD line remains low until the program resets the UBRK bit. A line break is detected if RXD remains low for 10 bit times or longer after a missing stop bit is detected. 20.2.10 Parity Generation and Detection Parity is only generated or checked with the 7-bit and 8-bit data formats. It is not generated or checked in the diagnostic loopback mode, the attention mode, or in normal mode with the 9-bit data format. Parity generation and checking are enabled and disabled using the PEN bit in the UnFRS register. The UPSEL bits in the UnFRS register are used to select odd, even, or no parity.
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20.3
UART REGISTERS
Name U1MDSL2 U1SPOS U2RBUF U2TBUF U2PSR U2BAUD U2FRS U2MDSL1 U2STAT U2ICTRL U2OVR U2MDSL2 U2SPOS U3RBUF U3TBUF U3PSR U3BAUD U3FRS U3MDSL1 U3STAT U3ICTRL
Table 60
UART Registers Description UART1 Mode Select Register 2 UART1 Sample Position Register UART2 Receive Data Buffer UART2 Transmit Data Buffer UART2 Baud Rate Prescaler UART2 Baud Rate Divisor UART2 Frame Select Register UART2 Mode Select Register 1 UART2 Status Register UART2 Interrupt Control Register UART2 Oversample Rate Register UART2 Mode Select Register 2 UART2 Sample Position Register UART3 Receive Data Buffer UART3 Transmit Data Buffer UART3 Baud Rate Prescaler UART3 Baud Rate Divisor UART3 Frame Select Register UART3 Mode Select Register 1 UART3 Status Register UART3 Interrupt Control Register
Software interacts with the UART modules by accessing the UART registers, as listed in Table 60. Table 60 UART Registers Name U0RBUF U0TBUF U0PSR U0BAUD U0FRS U0MDSL1 U0STAT U0ICTRL U0OVR U0MDSL2 U0SPOS U1RBUF U1TBUF U1PSR U1BAUD U1FRS U1MDSL1 U1STAT U1ICTRL U1OVR Address FF F202h FF F200h FF F20Eh FF F20Ch FF F208h FF F20Ah FF F206h FF F204h FF F210h FF F212h FF F214h FF F222h FF F220h FF F22Eh FF F22Ch FF F228h FF F22Ah FF F226h FF F224h FF F230h Description UART0 Receive Data Buffer UART0 Transmit Data Buffer UART0 Baud Rate Prescaler UART0 Baud Rate Divisor UART0 Frame Select Register UART0 Mode Select Register 1 UART0 Status Register UART0 Interrupt Control Register UART0 Oversample Rate Register UART0 Mode Select Register 2 UART0 Sample Position Register UART1 Receive Data Buffer UART1 Transmit Data Buffer UART1 Baud Rate Prescaler UART1 Baud Rate Divisor UART1 Frame Select Register UART1 Mode Select Register 1 UART1 Status Register UART1 Interrupt Control Register UART1 Oversample Rate Register
Address FF F232h FF F234h FF F242h FF F240h FF F24Eh FF F24Ch FF F248h FF F24Ah FF F246h FF F244h FF F250h FF F252h FF F254h FF F262h FF F260h FF F26Eh FF F26Ch FF F268h FF F26Ah FF F266h FF F264h
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Table 60 UART Registers Name U3OVR U3MDSL2 U3SPOS 20.3.1 Address FF F270h FF F272h FF F274h Description UART3 Oversample Rate Register UART3 Mode Select Register 2 UART3 Sample Position Register
20.3.4
UART Baud Rate Divisor (UnBAUD)
The UnBAUD register is a byte-wide, read/write register that contains the lower eight bits of the baud rate divisor. The register contents are unknown at power-up and are left unchanged by a reset operation. The register format is shown below. 7 UDIV7:0 0
UART Receive Data Buffer (UnRBUF)
UDIV7:0
The UnRBUF register is a byte-wide, read/write register used to receive each data byte. 7 URBUF 0 20.3.5
The Baud Rate Divisor field holds the eight lowest-order bits of the UART baud rate divisor used in the second stage of the two-stage divider chain. The three most significant bits are held in the UnPSR register. The divisor value used is (UDIV[10:0] + 1). UART Frame Select Register (UnFRS)
20.3.2
UART Transmit Data Buffer (UnTBUF)
The UnTBUF register is a byte-wide, read/write register used to transmit each data byte. 7 UnTBUF 0
The UnFRS register is a byte-wide, read/write register that controls the frame format, including the number of data bits, number of stop bits, and parity type. This register is cleared upon reset. The register format is shown below. 7 6 5 4 3 UXB9 2 USTP 1 0
Reserved UPEN
UPSEL
UCHAR
20.3.3
UART Baud Rate Prescaler (UnPSR)
UCHAR
The UnPSR register is a byte-wide, read/write register that contains the 5-bit clock prescaler and the upper three bits of the baud rate divisor. This register is cleared upon reset. The register format is shown below. 7 UPSC 3 2 UDIV10:8 0 USTP
UPSC
UDIV10:8
The Prescaler field specifies the prescaler value used for dividing the System Clock in the UXB9 first stage of the two-stage divider chain. For the prescaler factors corresponding to each 5bit value, see Table 59. The Baud Rate Divisor field holds the three most significant bits (bits 10, 9, and 8) of the UART baud rate divisor used in the second UPSEL stage of the two-stage divider chain. The remaining bits of the baud rate divisor are held in the UnBAUD register.
The Character Frame Format field selects the number of data bits per frame, not including the parity bit, as follows: 00 - 8 data bits per frame. 01 - 7 data bits per frame. 10 - 9 data bits per frame. 11 - Loop-back mode, 9 data bits per frame. The Stop Bits bit specifies the number of stop bits transmitted in each frame. If this bit is 0, one stop bit is transmitted. If this bit is 1, two stop bits are transmitted. 0 - One stop bit per frame. 1 - Two stop bits per frame. The Transmit 9th Data Bit holds the value of the ninth data bit, either 0 or 1, transmitted when the UART is configured to transmit nine data bits per frame. It has no effect when the UART is configured to transmit seven or eight data bits per frame. The Parity Select field selects the treatment of the parity bit. When the UART is configured to transmit nine data bits per frame, the parity bit is omitted and the UPSEL field is ignored. 00 - Odd parity. 01 - Even parity. 10 - No parity, transmit 1 (mark). 11 - No parity, transmit 0 (space).
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CP3CN23
UPEN
The Parity Enable bit enables or disables parity generation and parity checking. When the UART is configured to transmit nine data bits per frame, there is no parity bit and the UnPEN bit is ignored. 0 - Parity generation and checking disabled. 1 - Parity generation and checking enabled. UART Mode Select Register 1 (UnMDSL1)
UERD
20.3.6
UFCE
The UnMDSL1 register is a byte-wide, read/write register that selects the clock source, synchronization mode, attention mode, and line break generation. This register is cleared at reset. The register format is shown below. 7 6 5 4 3 2 1 0
URTS
URTS UFCE UERD UETD UCKS UBRK UATN UMOD 20.3.7 UMOD The Mode bit selects between synchronous and asynchronous mode. Synchronous mode is only available for the UART0 module. 0 - Asynchronous mode. 1 - Synchronous mode. The Attention Mode bit is used to enable Attention mode. When set, this bit selects the attention mode of operation for the UART. When clear, the attention mode is disabled. The hardware clears this bit after an address frame is received. An address frame is a 9-bit character with a 1 in the ninth bit position. 0 - Attention mode disabled. 1 - Attention mode enabled. The Force Transmission Break bit is used to force the TXD output low. Setting this bit to 1 causes the TXD pin to go low. TXD remains low until the UBRK bit is cleared by software. 0 - Normal operation. 1 - TXD pin forced low. The Synchronous Clock Source bit controls the clock source when the UART operates in the synchronous mode (UMOD = 1). This functionality is only available for the UART0 module. If the UCKS bit is set, the UART operates from an external clock provided on the CKX pin. If the UCKS bit is clear, the UART operates from the baud rate clock produced by the UART on the CKX pin. This bit is ignored when the UART operates in the asynchronous mode. 0 - Internal baud rate clock is used. 1 - External clock is used. The Enable Transmit DMA bit controls whether DMA is used for UART transmit operations. Enabling transmit DMA automatically disables transmit interrupts, without regard to the state of the UETI bit. 0 - Transmit DMA disabled. 1 - Transmit DMA enabled.
The Enable Receive DMA bit controls whether DMA is used for UART receive operations. Enabling receive DMA automatically disables receive interrupts, without regard to the state of the UERI bit. Receive error interrupts are unaffected by the UERD bit. 0 - Receive DMA disabled. 1 - Receive DMA enabled. The Flow Control Enable bit controls whether flow control interrupts are enabled. 0 - Flow control interrupts disabled. 1 - Flow control interrupts enabled. The Ready To Send bit directly controls the state of the RTS output. 0 - RTS output is high. 1 - RTS output is low. UART Status Register (UnSTAT)
The UnSTAT register is a byte-wide, read-only register that contains the receive and transmit status bits. This register is cleared upon reset. Any attempt by software to write to this register is ignored. The register format is shown below. 7 Res. 6 5 4 3 2 1 0
UATN
UXMIP URB9 UBKD UERR UDOE UFE UPE
UPE
UBRK
UFE
UCKS
UDOE
UERR
UETD
The Parity Error bit indicates whether a parity error is detected within a received character. This bit is automatically cleared by the hardware when the UnSTAT register is read. 0 - No parity error occurred. 1 - Parity error occurred. The Framing Error bit indicates whether the UART fails to receive a valid stop bit at the end of a frame. This bit is automatically cleared by the hardware when the UnSTAT register is read. 0 - No framing error occurred. 1 - Framing error occurred. The Data Overrun Error bit is set when a new character is received and transferred to the UnRBUF register before software has read the previous character from the UnRBUF register. This bit is automatically cleared by the hardware when the UnSTAT register is read. 0 - No receive overrun error occurred. 1 - Receive overrun error occurred. The Error Status bit indicates when a parity, framing, or overrun error occurs (any time that the UPE, UFE, or UDOE bit is set). It is automatically cleared by the hardware when the UPE, UFE, and UDOE bits are all 0. 0 - No receive error occurred. 1 - Receive error occurred.
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UBKD
URB9
UXMIP
The Break Detect bit indicates when a line break condition occurs. This condition is detected if RXD remains low for at least ten bit times after a missing stop bit has been detected at the end of a frame. The hardware automatically clears the UBKD bit on reading the UnSTAT register, but only if the break condition on RXD no longer exists. If reading the UnSTAT register does not clear the UBKD bit because the break is still actively driven on the line, the hardware clears the bit as soon as the break condition no longer exists (when the RXD input returns to a high level). 0 - No break condition occurred. 1 - Break condition occurred. The Received 9th Data Bit holds the ninth data bit, when the UART is configured to operate in the 9-bit data format. The Transmit In Progress bit indicates when the UART is transmitting. The hardware sets this bit when the UART is transmitting data and clears the bit at the end of the last frame bit. 0 - UART is not transmitting. 1 - UART is transmitting. UART Interrupt Control Register (UnICTRL)
UCTS
UEFCI
UETI
UERI
UEEI
20.3.8
The UnICTRL register is a byte-wide register that contains the receive and transmit interrupt status bits (read-only bits) and the interrupt enable bits (read/write bits). The register is initialized to 01h at reset. The register format is shown below. 7 6 5 4 3 2 1 0
The Clear To Send bit indicates the state on the CTS input. This functionality is only available for the UART0 module. 0 - CTS input is high. 1 - CTS input is low. The Enable Flow Control Interrupt bit controls whether a flow control interrupt is generated when the UDCTS bit changes from clear to set. This functionality is only available for the UART0 module. 0 - Flow control interrupt disabled. 1 - Flow control interrupt enabled. The Enable Transmitter Interrupt bit, when set, enables generation of an interrupt when the hardware sets the UTBE bit. 0 - Transmit buffer empty interrupt disabled. 1 - Transmit buffer empty interrupt enabled. The Enable Receiver Interrupt bit, when set, enables generation of an interrupt when the hardware sets the URBF bit. 0 - Receive buffer full interrupt disabled. 1 - Receive buffer full interrupt enabled. The Enable Receive Error Interrupt bit, when set, enables generation of an interrupt when the hardware sets the UERR bit in the UnSTAT register. 0 - Receive error interrupt disabled. 1 - Receive error interrupt enabled. UART Oversample Rate Register (UnOVR)
20.3.9
The UnOVR register is a byte-wide, read/write register that specifies the oversample rate. At reset, the UnOVR register is cleared. The register format is shown below. 7 Reserved 4 3 UOVSR 0
UEEI UERI UETI UEFCI UCTS UDCTS URBF UTBE
UTBE
URBF
UDCTS
The Transmit Buffer Empty bit is set by hardware when the UART transfers data from the UOVSR UnTBUF register to the transmit shift register for transmission. It is automatically cleared by the hardware on the next write to the UnTBUF register. 0 - Transmit buffer is loaded. 1 - Transmit buffer is empty. The Receive Buffer Full bit is set by hardware when the UART has received a complete data frame and has transferred the data from the receive shift register to the UnRBUF register. It is automatically cleared by the hardware when the UnRBUF register is read. 0 - Receive buffer is empty. 1 - Receive buffer is loaded. The Delta Clear To Send bit indicates whether the CTS input has changed state since the CPU last read this register. This functionality is only available for the UART0 module. 0 - No change since last read. 1 - State has changed since last read.
The Oversampling Rate field specifies the oversampling rate, as given in the following table. UOVSR3:0 0000-0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Oversampling Rate 16 7 8 9 10 11 12 13 14 15
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20.3.10 UART Mode Select Register 2 (UnMDSL2) The UnMDSL2 register is a byte-wide, read/write register that controls the sample mode used to recover asynchronous data. At reset, the UnOVR register is cleared. The register format is shown below. 7 Reserved 1 0 USMD
The USAMP field may be used to override the automatic selection, to choose any other clock period at which to start taking the three samples.
20.4
BAUD RATE CALCULATIONS
The UART baud rate is determined by the System Clock frequency and the values in the UnOVR, UnPSR, and UnBAUD registers. Unless the System Clock is an exact multiple of the baud rate, there will be a small amount of error in the resulting baud rate.
USMD
The USMD bit controls the sample mode for 20.4.1 Asynchronous Mode asynchronous transmission. 0 - UART determines the sample position au- The equation to calculate the baud rate in asynchronous mode is: tomatically. 1 - The UnSPOS register determines the SYS_CLK BR = ----------------------------sample position. (O x N x P) where BR is the baud rate, SYS_CLK is the System Clock, O is the oversample rate, N is the baud rate divisor + 1, and P is the prescaler divisor selected by the UPSR register. Assuming a System Clock of 5 MHz, a desired baud rate of 9600, and an oversample rate of 16, the N x P term according to the equation above is: ( 5 x10 ) N x P = ------------------------------ = 32.552 ( 16 x 9600 ) The N x P term is then divided by each Prescaler Factor from Table 59 to obtain a value closest to an integer. The factor for this example is 6.5. N = 32.552 = 5.008 (N = 5) ----------------6.5 The baud rate register is programmed with a baud rate divisor of 4 (N = baud rate divisor + 1). This produces a baud clock of: ( 5 x10 ) BR = ----------------------------------- = 9615.385 ( 16 x 5 x 6.5 ) %error = ( 9615.385 - 9600 ) = 0.16 -----------------------------------------------9600 Note that the percent error is much lower than would be possible without the non-integer prescaler factor. Error greater than 3% is marginal and may result in unreliable operation. Refer to Table 61 below for more examples.
6 6
20.3.11 UART Sample Position Register (UnSPOS) The UnSPOS register is a byte-wide, read/write register that specifies the sample position when the USMD bit in the UnMDSL2 register is set. At reset, the UnSPOS register is initialized to 06h. The register format is shown below. 7 Reserved 4 3 USAMP 0
USAMP
The Sample Position field specifies the oversample clock period at which to take the first of three samples for sensing the value of data bits. The clocks are numbered starting at 0 and may range up to 15 for 16x oversampling. The maximum value for this field is (oversampling rate - 3). The table below shows the clock period at which each of the three samples is taken, when automatic sampling is enabled (UnMDSL2.USMD = 0). Sample Position Oversampling Rate 1 7 8 9 10 11 12 13 14 15 16 2 2 3 3 4 4 5 5 6 6 2 3 3 4 4 5 5 6 6 7 7 3 4 4 5 5 6 6 7 7 8 8
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20.4.2
Synchronous Mode
Synchronous mode is only available for the UART0 module. When synchronous mode is selected and the UCKS bit is set, the UART operates from a clock received on the CKX pin. When the UCKS bit is clear, the UART uses the clock Use the same procedure to determine the values of N and from the internal baud rate generator which is also driven on P as in the asynchronous mode. In this case, however, only the CKX pin. When the internal baud rate generator is used, integer prescaler values are allowed. the equation for calculating the baud rate is: SYS_CLK BR = ---------------------------(2 x N x P) Table 61 Baud Rate Programming Baud Rate 300 600 1200 1800 2000 2400 3600 4800 7200 9600 14400 19200 38400 56000 115200 128000 230400 345600 460800 576000 691200 806400 921600 1105920 1382400 1536000 SYS_CLK = 48 MHz O 16 16 16 7 16 16 8 16 12 16 11 10 10 7 7 15 13 9 13 8 10 7 13 11 10 9 N 2000 2000 1250 401 1500 1250 1111 625 101 125 202 250 125 49 17 25 16 1 8 7 7 1 4 4 1 1 P 5.0 2.5 2.0 9.5 1.0 1.0 1.5 1.0 5.5 2.5 1.5 1.0 1.0 2.5 3.5 1.0 1.0 %err 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.00 0.04 0.04 0.00 0.16 SYS_CLK = 24 MHz O 16 16 16 8 16 16 12 16 11 10 11 10 10 13 13 15 13 10 13 12 10 15 13 11 7 8 N 2000 1250 1250 1111 750 625 101 125 303 250 101 125 25 33 16 5 8 7 4 1 1 2 2 2 1 2 P 2.5 2.0 1.0 1.5 1.0 1.0 5.5 2.5 1.0 1.0 1.5 1.0 2.5 1.0 1.0 2.5 1.0 1.0 1.0 3.5 3.5 1.0 1.0 1.0 2.5 1.0 %err 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.00 0.10 0.16 0.00 0.16 0.79 0.16 0.79 0.79 0.79 0.16 1.36 0.79 2.34 SYS_CLK = 12 MHz O 16 16 16 12 16 16 11 10 11 10 14 10 16 13 13 11 13 10 13 14 7 10 13 N 1250 1250 625 101 250 125 202 250 101 125 17 25 13 11 8 1 4 1 2 1 1 1 1 P 2.0 1.0 1.0 5.5 1.5 2.5 1.5 1.0 1.5 1.0 3.5 2.5 1.5 1.5 1.0 8.5 1.0 3.5 1.0 1.5 2.5 1.5 1.0 %err 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.00 0.01 0.00 0.04 0.00 0.16 0.10 0.16 0.27 0.16 0.79 0.16 0.79 0.79 0.79 0.16 9 1 1.0 0.47 11 7 2 1 1.0 2.5 1.36 0.79 SYS_CLK = 10 MHz O 13 13 13 12 16 9 11 7 10 7 14 16 8 7 7 12 11 N 1282 1282 641 463 125 463 101 119 139 149 33 13 13 17 5 1 4 P 2.0 1.0 1.0 1.0 2.5 1.0 2.5 2.5 1.0 1.0 1.5 2.5 2.5 1.5 2.5 6.5 1.0 %err 0.00 0.00 0.00 0.01 0.00 0.01 0.01 0.04 0.08 0.13 0.21 0.16 0.16 0.04 0.79 0.16 1.36
where BR is the baud rate, SYS_CLK is the System Clock, N is the value of the baud rate divisor + 1, and P is the prescaler divide factor selected by the value in the UnPSR register. Oversampling is not used in synchronous mode.
15.5 0.44 1.0 1.5 1.0 8.5 1.0 1.0 3.5 3.5 0.16 0.79 0.79 0.04 0.16 1.36 0.79 0.79
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Table 62 Baud Rate Programming Baud Rate 300 600 1200 1800 2000 2400 3600 4800 7200 9600 14400 19200 38400 56000 115200 128000 230400 345600 460800 576000 Baud Rate 300 600 1200 1800 2000 2400 3600 4800 7200 9600 14400 19200 38400 56000 115200 128000 230400 SYS_CLK = 8 MHz O 7 12 12 8 16 11 11 11 11 14 15 7 16 13 10 9 10 15 7 7 N 401 1111 101 101 250 303 202 101 101 17 37 17 13 11 7 7 1 1 1 2 P 9.5 1.0 5.5 5.5 1.0 1.0 1.0 1.5 1.0 3.5 1.0 3.5 1.0 1.0 1.0 1.0 3.5 1.5 2.5 1.0 %err 0.00 0.01 0.01 0.01 0.00 0.01 0.01 0.01 0.01 0.04 0.10 0.04 0.16 0.10 0.79 0.79 0.79 2.88 0.79 0.79 SYS_CLK = 6 MHz O 16 16 16 11 16 10 11 10 14 10 7 16 8 9 13 16 13 7 13 7 N 1250 625 125 303 125 250 101 125 17 25 17 13 13 12 4 3 2 1 1 1 P 1.0 1.0 2.5 1.0 1.5 1.0 1.5 1.0 3.5 2.5 3.5 1.5 1.5 1.0 1.0 1.0 1.0 2.5 1.0 1.5 %err 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.00 0.04 0.00 0.04 0.16 0.16 0.79 0.16 2.34 0.16 0.79 0.16 0.79 SYS_CLK = 1 MHz O 11 11 14 15 10 7 9 16 9 16 10 8 13 9 N 202 101 17 37 50 17 31 13 1 1 7 1 2 2 P 1.5 1.5 3.5 1.0 1.0 3.5 1.0 1.0 %err 0.01 0.01 0.04 0.10 0.00 0.04 0.44 0.16 SYS_CLK = 500 kHz O 11 14 7 9 10 16 9 16 10 8 10 13 13 N 101 17 17 31 25 13 1 1 7 1 1 2 1 P 1.5 3.5 3.5 1.0 1.0 1.0 %err 0.01 0.04 0.04 0.44 0.00 0.16 SYS_CLK = 5 MHz O 11 11 10 11 10 7 10 7 14 16 7 8 13 15 11 13 11 N 202 101 119 101 250 119 139 149 33 13 33 13 10 6 4 3 2 P 7.5 7.5 3.5 2.5 1.0 2.5 1.0 1.0 1.5 2.5 1.5 2.5 1.0 1.0 1.0 1.0 1.0 %err 0.01 0.01 0.04 0.01 0.00 0.04 0.08 0.13 0.21 0.16 0.21 0.16 0.16 0.79 1.36 0.16 1.36 SYS_CLK = 4 MHz O 12 12 11 11 16 11 11 14 15 7 9 16 16 13 10 9 7 N 202 101 202 202 125 101 101 17 37 17 31 13 1 1 1 1 1 P 5.5 5.5 1.5 1.0 1.0 1.5 1.0 3.5 1.0 3.5 1.0 1.0 6.5 5.5 3.5 3.5 2.5 %err 0.01 0.01 0.01 0.01 0.00 0.01 0.01 0.04 0.10 0.04 0.44 0.16 0.16 0.10 0.79 0.79 0.79
SYS_CLK = 3 MHz O 16 16 10 11 15 10 14 10 7 16 13 8 13 9 13 16 13 N 250 125 250 101 100 125 17 25 17 13 16 13 6 6 2 1 1 P 2.5 2.5 1.0 1.5 1.0 1.0 3.5 2.5 3.5 1.5 1.0 1.5 1.0 1.0 1.0 1.5 1.0 %err 0.00 0.00 0.00 0.01 0.00 0.00 0.04 0.00 0.04 0.16 0.16 0.16 0.16 0.79 0.16 2.34 0.16
SYS_CLK = 2 MHz O 12 11 11 11 16 14 15 7 9 16 9 16 8 9 7 8 N 101 202 101 101 25 17 37 17 31 13 1 1 1 4 1 2 P 5.5 1.5 1.5 1.0 2.5 3.5 1.0 3.5 1.0 1.0 %err 0.01 0.01 0.01 0.01 0.00 0.04 0.10 0.04 0.44 0.16
15.5 0.44 6.5 1.0 6.5 3.5 1.0 1.0 0.16 0.79 0.16 0.79 0.16 0.16
15.5 0.44 6.5 1.0 6.5 1.0 1.0 0.16 0.79 0.16 0.16 0.79
15.5 0.44 6.5 6.5 1.0 2.5 1.0 0.16 0.16 0.79 0.79 2.34
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21.0 Microwire/SPI Interface
Microwire/Plus is a synchronous serial communications protocol, originally implemented in National Semiconductor's COP8(R) and HPC families of microcontrollers to minimize the number of connections, and therefore the cost, of communicating with peripherals. The CP3CN23 has an enhanced Microwire/SPI interface module (MWSPI) that can communicate with all peripherals that conform to Microwire or Serial Peripheral Interface (SPI) specifications. This enhanced Microwire interface is capable of operating as either a master or slave and in 8- or 16-bit mode. Figure 65 shows a typical enhanced Microwire interface application. The enhanced Microwire interface module includes the following features: Programmable operation as a Master or Slave Programmable shift-clock frequency (master only) Programmable 8- or 16-bit mode of operation 8- or 16-bit serial I/O data shift register Two modes of clocking data Serial clock can be low or high when idle 16-bit read buffer Busy bit, Read Buffer Full bit, and Overrun bit for polling and as interrupt sources Supports multiple masters Maximum bit rate of 12M bits/second (master mode) 6M bits/second (slave mode) at 24 MHz System Clock Supports very low-end slaves with the Slave Ready output Echo back enable/disable (Slave only)
MWCS GPIO
CS 8-Bit A/D
CS 1K Bit EEPROM
CS LCD Display Driver DI SK DI
CS VF Display Driver SK DI
I/O Lines
Master DO
Slave
I/O Lines
SK
DI
DO
SK
MDIDO MDODI MSK
MDIDO MDODI MSK DS067
Figure 65.
Microwire Interface 21.1.1 Shifting
21.1
MICROWIRE OPERATION
The Microwire interface allows several devices to be connected on one three-wire system. At any given time, one of these devices operates as the master while all other devices operate as slaves. The Microwire interface allows the device to operate either as a master or slave transferring 8- or 16bits of data.
The master device supplies the synchronous clock (MSK) for the serial interface and initiates the data transfer. The slave devices respond by sending (or receiving) the requested data. Each slave device uses the master's clock for The shift in and shift out are controlled by the MSK clock. In serially shifting data out (or in), while the master shifts the each clock cycle of MSK, one bit of data is transmitted/received. The 16-bit shifter is accessible as the MWDAT regdata in (or out). ister. Reading the MWDAT register returns the value in the The three-wire system includes: the serial data in signal read buffer. Writing to the MWDAT register updates the 16(MDIDO for master mode, MDODI for slave mode), the sebit shifter. rial data out signal (MDODI for master mode, MDIDO for slave mode), and the serial clock (MSK). In slave mode, an optional fourth signal (MWCS) may be used to enable the slave transmit. At any given time, only one slave can respond to the master. Each slave device has its own chip select signal (MWCS) for this purpose. Figure 66 shows a block diagram of the enhanced Microwire serial interface in the device. www.national.com 148
The Microwire interface is a full duplex transmitter/receiver. A 16-bit shifter, which can be split into a low and high byte, is used for both transmitting and receiving. In 8-bit mode, only the lower 8-bits are used to transfer data. The transmitted data is shifted out through MDODI pin (master mode) or MDIDO pin (slave mode), starting with the most significant bit. At the same time, the received data is shifted in through MDIDO pin (master mode) or MDODI pin (slave mode), also starting with the most significant bit first.
CP3CN23
Interrupt Request
Control + Status
MWCS
Write Data
16-BIt Read Buffer
Write Data
8
8 MWDAT
16-BIt Shift Register
Data Out
Slave Master MDODI
Data In
Slave Master MDIDO
MSK
MSK
System Clock
Clock Prescaler + Select Master DS068
Figure 66. 21.1.2 Reading
Microwire Block Diagram 21.1.4 Clocking Modes
The enhanced Microwire interface implements a double buffer on read. As illustrated in Figure 66, the double read buffer consists of the 16-bit shifter and a buffer, called the read buffer.
Two clocking modes are supported: the normal mode and the alternate mode.
In the normal mode, the output data, which is transmitted on the MDODI pin (master mode) or the MDIDO pin (slave The 16-bit shifter loads the read buffer with new data when mode), is clocked out on the falling edge of the shift clock the data transfer sequence is completed and previous data MSK. The input data, which is received via the MDIDO pin in the read buffer has been read. In master mode, an Over- (master mode) or the MDODI pin (slave mode), is sampled run error occurs when the read buffer is full, the 16-bit shifter on the rising edge of MSK. is full and a new data transfer sequence starts. In the alternate mode, the output data is shifted out on the When 8-bit mode is selected, the lower byte of the shift reg- rising edge of MSK on the MDODI pin (master mode) or ister is loaded into the lower byte of the read buffer and the MDIDO pin (slave mode). The input data, which is received read buffer's higher byte remains unchanged. via MDIDO pin (master mode) or MDODI pin (slave mode), The RBF bit indicates if the MWDAT register holds valid da- is sampled on the falling edge of MSK. ta. The OVR bit indicates that an overrun condition has occurred. The clocking modes are selected with the SCM bit. The SCIDL bit allows selection of the value of MSK when it is idle (when there is no data being transferred). Various MSK 21.1.3 Writing clock frequencies can be programmed via the MCDV bits. The BSY bit indicates whether the MWDAT register can be Figures Figure 67, Figure 68, Figure 69, and Figure 70 show written. All write operations to the MWDAT register update the the data transfer timing for the normal and the alternate shifter while the data contained in the read buffer is not affect- modes with the SCIDL bit clear and set. ed. Undefined results will occur if the MWDAT register is writNote that when data is shifted out on MDODI (master mode) ten to while the BSY bit is set. or MDIDO (slave mode) on the leading edge of the MSK clock, bit 14 (16-bit mode) is shifted out on the second leading edge of the MSK clock. When data are shifted out on MDODI (master mode) or MDIDO (slave mode) on the trailing edge of MSK, bit 14 (16-bit mode) is shifted out on the first trailing edge of MSK.
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21.2
MASTER MODE
In Master mode, the MSK pin is an output for the shift clock, MSK. When data is written to the MWDAT register, eight or sixteen MSK clocks, depending on the mode selected, are
generated to shift the 8 or 16 bits of data, and then MSK goes idle again. The MSK idle state can be either high or low, depending on the SCIDL bit.
End of Transfer MSK Shift Out Bit 0 (LSB)
Data Out
MSB
MSB - 1
MSB - 2
Bit 1
Sample Point Data In MSB MSB - 1 MSB - 2 Bit 1 Bit 0 (LSB) DS069
Figure 67.
Normal Mode (SCIDL = 0)
End of Transfer
MSK Shift Out Bit 0 (LSB)
Data Out
MSB Sample Point
MSB - 1
MSB - 2
Bit 1
Data In
MSB
MSB - 1
MSB - 2
Bit 1
Bit 0 (LSB)
DS070
Figure 68.
Normal Mode (SCIDL = 1)
End of Transfer
MSK Shift Out
Data Out
MSB
MSB - 1
MSB - 2
Bit 1
Bit 0 (LSB)
Sample Point Data In MSB MSB - 1 MSB - 2 Bit 1 Bit 0 (LSB)
DS071
Figure 69. Alternate Mode (SCIDL = 0)
End of Transfer MSK Shift Out
Data Out
MSB
MSB - 1
MSB - 2
Bit 1
Bit 0 (LSB)
Sample Point Data In MSB MSB - 1 MSB - 2 Bit 1 Bit 0 (LSB)
DS072
Figure 70. Alternate Mode (SCIDL = 1)
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21.3
SLAVE MODE
21.4
INTERRUPT GENERATION
In Slave mode, the MSK pin is an input for the shift clock MSK. MDIDO is placed in TRI-STATE mode when MWCS is inactive. Data transfer is enabled when MWCS is active. The slave starts driving MDIDO when MWCS is active. The most significant bit (lower byte in 8-bit mode or upper byte in 16-bit mode) is output onto the MDIDO pin first. After eight or sixteen clocks (depending on the selected mode), the data transfer is completed. If a new shift process starts before MWDAT was written, i.e., while MWDAT does not contain any valid data, and the ECHO bit is set, the data received from MDODI is transmitted on MDIDO in addition to being shifted to MWDAT. If the ECHO bit is clear, the data transmitted on MDIDO is the data held in the MWDAT register, regardless of its validity. The master may negate the MWCS signal to synchronize the bit count between the master and the slave. In the case that the slave is the only slave in the system, MWCS can be tied to ground.
Interrupts may be enabled for any of the conditions shown in Table 63. Table 63 Microwire Interrupt Trigger Condition Interrupt Status Enable Bit Bit in the Condition in the MWSTAT MWCTRL1 Register Register
Description
Not Busy
BSY
EIW
The shifter is ready for the next data transfer sequence. The read buffer is full and waiting to be unloaded. A new data transfer sequence started while both the shifter and the read buffer were full.
Read Buffer Full
RBF
EIR
Overrun
OVF
EIO
Figure 71 illustrates the interrupt generation logic of this module.
EIO
OVR = 1
EIR
RBF = 1
MWSPI Interrupt
EIW
BSY = 0 DS073
Figure 71.
MWSPI Interrupts
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21.5
MICROWIRE INTERFACE REGISTERS
21.5.2
MICROWIRE Control Register (MWCTL1)
Software interacts with the Microwire interface by accessing The MWCTL1 register is a word-wide, read/write register used to control the Microwire module. To avoid clock glitchthe Microwire registers. There are three such registers: es, the MWEN bit must be clear while changing the states Table 64 Microwire Interface Registers of any other bits in the register. At reset, all non-reserved bits are cleared. The register format is shown below. Name Address Description MWDAT MWCTL1 MWSTAT 21.5.1 FF F3A0h FF F3A2h FF F3A4h Microwire Data Register Microwire Control Register Microwire Status Register 15 SCDV 9 8 SCIDL 7 SCM 6 EIW 5 EIR 4 EIO 3 2 1 0
ECHO MOD
MNS MWEN
Microwire Data Register (MWDAT)
MWEN
The MWDAT register is a word-wide, read/write register used to transmit and receive data through the MDODI and MDIDO pins. The register format is shown below. 7 MWDAT 0
The Microwire Enable bit controls whether the Microwire interface module is enabled. 0 - Microwire module disabled. 1 - Microwire module enabled. Clearing this bit disables the module, clears the status bits in the Microwire status register (the BSY, RBF, and OVR bits in MWSTAT), and places the Microwire interface pins in the states described below. Pin MSK MWCS State When Disabled Master - SCIDL Bit Slave - Input Input Master - Input Slave - TRI-STATE Master - Known value Slave - Input
Figure 72 shows the hardware structure of the register.
MWDAT Write
DIN
Shifter (Low Byte)
Shifter (High Byte)
1 DOUT 0
MDIDO MDODI MNS
DS074
Read Buffer (Low Byte)
Read Buffer (High Byte)
MOD
Read
Figure 72.
MWDAT Register MOD
ECHO
The Master/Slave Select bit controls whether the CP3CN23 is a master or slave. When clear, the device operates as a slave. When set, the device operates as the master. 0 - CP3CN23 is slave. 1 - CP3CN23 is master. The Mode Select bit controls whether 8- or 16bit mode is used. When clear, the device operates in 8-bit mode. When set, the device operates in 16-bit mode. This bit must only be changed when the module is disabled or idle (MWSTAT.BSY = 0). 0 - 8-bit mode. 1 - 16-bit mode. The Echo Back bit controls whether the echo back function is enabled in slave mode. This bit must be written only when the Microwire interface is idle (MWSTAT.BSY=0). The ECHO bit is ignored in master mode. The MWDAT register is valid from the time the register has been written until the end of the transfer. In the echo back mode, MDODI is transmitted (echoed back) on MDIDO if the MWDAT register does not contain any valid data. With the echo back function disabled, the data held in the
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EIO
EIR
EIW
SCM
SCIDL
SCDV
MWDAT register is transmitted on MDIDO, whether or not the data is valid. 0 - Echo back disabled. 1 - Echo back enabled. The Enable Interrupt on Overrun bit enables or disables the overrun error interrupt. When set, an interrupt is generated when the Receive Overrun Error bit (MWSTAT.OVR) is set. Otherwise, no interrupt is generated when an overrun error occurs. This bit must only be enabled in master mode. 0 - Disable overrun error interrupts. 1 - Enable overrun error interrupts. The Enable Interrupt for Read bit controls whether an interrupt is generated when the read buffer becomes full. When set, an interrupt is generated when the Read Buffer Full bit (MWSTAT.RBF) is set. Otherwise, no interrupt is generated when the read buffer is full. 0 - No read buffer full interrupt. 1 - Interrupt when read buffer becomes full. The Enable Interrupt for Write bit controls whether an interrupt is generated when the Busy bit (MWSTAT.BSY) is cleared, which indicates that a data transfer sequence has been completed and the read buffer is ready to receive the new data. Otherwise, no interrupt is generated when the Busy bit is cleared. 0 - No interrupt on data transfer complete. 1 - Interrupt on data transfer complete. The Shift Clock Mode bit selects between the normal clocking mode and the alternate clocking mode. In the normal mode, the output data is clocked out on the falling edge of MSK and the input data is sampled on the rising edge of MSK. In the alternate mode, the output data is clocked out on the rising edge of MSK and the input data is sampled on the falling edge of MSK. 0 - Normal clocking mode. 1 - Alternate clocking mode. The Shift Clock Idle bit controls the value of the MSK output when the Microwire module is idle. This bit must be changed only when the Microwire module is disabled (MEN = 0) or when no bus transaction is in progress (MWSTAT.BSY = 0). 0 - MSK is low when idle. 1 - MSK is high when idle The Shift Clock Divider Value field specifies the divisor used for generating the MSK shift clock from the System Clock. The divisor is 2 x (SCDV[6:0] + 1). Valid values are 0000001b to 1111111b, so the division ratio may range from 3 to 256. This field is ignored in slave mode (MWCTL1.MNS=0).
21.5.3
Microwire Status Register (MWSTAT)
The MWSTAT register is a word-wide, read-only register that shows the current status of the Microwire interface module. At reset, all non-reserved bits are clear. The register format is shown below. 15 Reserved 3 2 OVR 1 RBF 0 BSY
BSY
RBF
OVR
The Busy bit, when set, indicates that the Microwire shifter is busy. In master mode, the BSY bit is set when the MWDAT register is written. In slave mode, the bit is set on the first leading edge of MSK when MWCS is asserted or when the MWDAT register is written, whichever occurs first. In both master and slave modes, this bit is cleared when the Microwire data transfer sequence is completed and the read buffer is ready to receive the new data; in other words, when the previous data held in the read buffer has already been read. If the previous data in the read buffer has not been read and new data has been received into the shift register, the BSY bit will not be cleared, as the transfer could not be completed because the contents of the shift register could not be transferred into the read buffer. 0 - Microwire shifter is not busy. 1 - Microwire shifter is busy. The Read Buffer Full bit, when set, indicates that the Microwire read buffer is full and ready to be read by software. It is set when the shifter loads the read buffer, which occurs upon completion of a transfer sequence if the read buffer is empty. The RBF bit is updated when the MWDAT register is read. At that time, the RBF bit is cleared if the shifter does not contain any new data (in other words, the shifter is not receiving data or has not yet received a full byte of data). The RBF bit remains set if the shifter already holds new data at the time that MWDAT is read. In that case, MWDAT is immediately reloaded with the new data and is ready to be read by software. 0 - Microwire read buffer is not full. 1 - Microwire read buffer is full. The Receive Overrun Error bit, when set in master mode, indicates that a receive overrun error has occurred. This error occurs when the read buffer is full, the 8-bit shifter is full, and a new data transfer sequence starts. This bit is undefined in slave mode. The OVR bit, once set, remains set until cleared by software. Software clears this bit by writing a 1 to its bit position. Writing a 0 to this bit position has no effect. No other bits in the MWSTAT register are affected by a write operation to the register. 0 - No receive overrun error has occurred. 1 - Receive overrun error has occurred. www.national.com
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22.0 ACCESS.bus Interface
The ACCESS.bus interface module (ACB) is a two-wire serial interface compatible with the ACCESS.bus physical layer. It permits easy interfacing to a wide range of low-cost memories and I/O devices, including: EEPROMs, SRAMs, timers, A/D converters, D/A converters, clock chips, and peripheral drivers. It is compatible with Intel's SMBus and Philips' I2C bus. The ACB module can be configured as a bus master or slave, and can maintain bidirectional communications with both multiple master and slave devices. This section presents an overview of the bus protocol, and its implementation by the ACB module. ACCESS.bus master and slave Supports polling and interrupt-controlled operation Generate a wake-up signal on detection of a Start Condition, while in power-down mode Optional internal pull-up on SDA and SCL pins
SDA
SCL
Data Line Stable: Data Valid
Change of Data Allowed
DS075
Figure 73. Bit Transfer Each data transaction is composed of a Start Condition, a number of byte transfers (programmed by software), and a Stop Condition to terminate the transaction. Each byte is transferred with the most significant bit first, and after each byte, an Acknowledge signal must follow.
22.1
At each clock cycle, the slave can stall the master while it handles the previous data, or prepares new data. This can be performed for each bit transferred or on a byte boundary by the slave holding SCL low to extend the clock-low period. Typically, slaves extend the first clock cycle of a transfer if a byte read has not yet been stored, or if the next byte to be transmitted is not yet ready. Some microcontrollers with limThe ACCESS.bus protocol supports multiple master and ited hardware support for ACCESS.bus extend the access slave transmitters and receivers. Each bus device has a after each bit, to allow software time to handle this bit. unique address and can operate as a transmitter or a re- Start and Stop ceiver (though some peripherals are only receivers). The ACCESS.bus master generates Start and Stop CondiDuring data transactions, the master device initiates the tions (control codes). After a Start Condition is generated, transaction, generates the clock signal, and terminates the the bus is considered busy and it retains this status until a transaction. For example, when the ACB initiates a data certain time after a Stop Condition is generated. A high-totransaction with an ACCESS.bus peripheral, the ACB be- low transition of the data line (SDA) while the clock (SCL) is comes the master. When the peripheral responds and high indicates a Start Condition. A low-to-high transition of transmits data to the ACB, their master/slave (data transac- the SDA line while the SCL is high indicates a Stop Condition initiator and clock generator) relationship is unchanged, tion (Figure 74). even though their transmitter/receiver functions are reversed. The ACCESS.bus protocol uses a two-wire interface for bidirectional communication between the devices connected to the bus. The two interface signals are the Serial Data Line (SDA) and the Serial Clock Line (SCL). These signals should be connected to the positive supply, through pull-up resistors, to keep the signals high when the bus is idle. 22.1.1 Data Transactions
SDA
ACB PROTOCOL OVERVIEW
One data bit is transferred during each clock period. Data is sampled during the high phase of the serial clock (SCL). Consequently, throughout the clock high phase, the data must remain stable (see Figure 73). Any change on the SDA signal during the high phase of the SCL clock and in the middle of a transaction aborts the current transaction. New data must be driven during the low phase of the SCL clock. This protocol permits a single data line to transfer both command/control information and data using the synchronous serial clock.
SCL S Start Condition P Stop Condition DS076
Figure 74. Start and Stop Conditions In addition to the first Start Condition, a repeated Start Condition can be generated in the middle of a transaction. This allows another device to be accessed, or a change in the direction of the data transfer.
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Acknowledge Cycle The Acknowledge Cycle consists of two signals: the acknowledge clock pulse the master sends with each byte transferred, and the acknowledge signal sent by the receiving device (Figure 75).
Acknowledgment Signal from Receiver SDA MSB
Addressing Transfer Formats Each device on the bus has a unique address. Before any data is transmitted, the master transmits the address of the slave being addressed. The slave device should send an acknowledge signal on the SDA signal, once it recognizes its address. The address is the first seven bits after a Start Condition. The direction of the data transfer (R/W) depends on the bit sent after the address (the eighth bit). A low-to-high transition during a SCL high period indicates the Stop Condition, and ends the transaction (Figure 77).
P Stop Condition SDA
SCL S Start Condition
1
2
3-6
7
8
9 ACK
1
2
3-8
9 ACK
Byte Complete Interrupt Within Receiver
Clock Line Held Low by Receiver While Interrupt is Serviced
DS077 SCL 1-7 S Address R/W ACK Data ACK Data ACK Stop Condition DS079 8 9 1-7 8 9 1-7 8 9 P
Figure 75.
ACCESS.bus Data Transaction
The master generates the acknowledge clock pulse on the ninth clock pulse of the byte transfer. The transmitter releases the SDA line (permits it to go high) to allow the receiver to send the acknowledge signal. The receiver must pull down the SDA line during the acknowledge clock pulse, which signals the correct reception of the last data byte, and its readiness to receive the next byte. Figure 76 illustrates the acknowledge cycle.
Data Output by Transmitter Transmitter Stays Off the Bus During the Acknowledgment Clock Data Output by Receiver Acknowledgment Signal from Receiver SCL S Start Condition 1 2 3-6 7 8 9
Start Condition
Figure 77.
A Complete ACCESS.bus Data Transaction
When the address is sent, each device in the system compares this address with its own. If there is a match, the device considers itself addressed and sends an acknowledge signal. Depending upon the state of the R/W bit (1 = read, 0 = write), the device acts as a transmitter or a receiver. The ACCESS.bus protocol allows sending a general call address to all slaves connected to the bus. The first byte sent specifies the general call address (00h) and the second byte specifies the meaning of the general call (for example, "Write slave address by software only"). Those slaves that require the data acknowledge the call and become slave receivers; the other slaves ignore the call. Arbitration on the Bus Arbitration is required when multiple master devices attempt to gain control of the bus simultaneously. Control of the bus is initially determined according to address bits and clock cycle. If the masters are trying to address the same bus device, data comparisons determine the outcome of this arbitration. In master mode, the device immediately aborts a transaction if the value sampled on the SDA lines differs from the value driven by the device. (Exceptions to this rule are SDA while receiving data; in these cases the lines may be driven low by the slave without causing an abort.) The SCL signal is monitored for clock synchronization and allows the slave to stall the bus. The actual clock period will be the one set by the master with the longest clock period or by the slave stall period. The clock high period is determined by the master with the shortest clock high period. When an abort occurs during the address transmission, the master that identifies the conflict should give up the bus, switch to slave mode, and continue to sample SDA to see if it is being addressed by the winning master on the ACCESS.bus.
DS078
Figure 76. ACCESS.bus Acknowledge Cycle The master generates an acknowledge clock pulse after each byte transfer. The receiver sends an acknowledge signal after every byte received. There are two exceptions to the "acknowledge after every byte" rule. When the master is the receiver, it must indicate to the transmitter an end-of-data condition by not-acknowledging ("negative acknowledge") the last byte clocked out of the slave. This "negative acknowledge" still includes the acknowledge clock pulse (generated by the master), but the SDA line is not pulled down. When the receiver is full, otherwise occupied, or a problem has occurred, it sends a negative acknowledge to indicate that it cannot accept additional data bytes.
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22.2
ACB FUNCTIONAL DESCRIPTION
The ACB module provides the physical layer for an ACCESS.bus compliant serial interface. The module is configurable as either a master or slave device. As a slave, the ACB module may issue a request to become the bus master. 22.2.1 Master Mode
An ACCESS.bus transaction starts with a master device requesting bus mastership. It sends a Start Condition, followed by the address of the device it wants to access. If this transaction is successfully completed, software can assume that the device has become the bus master. For a device to become the bus master, software should perform the following steps: 1. Set the ACBCTL1.START bit, and configure the ACBCTL1.INTEN bit to the desired operation mode (Polling or Interrupt). This causes the ACB to issue a Start Condition on the ACCESS.bus, as soon as the ACCESS.bus is free (ACBCST.BB=0). It then stalls the bus by holding SCL low. 2. If a bus conflict is detected, (i.e., some other device pulls down the SCL signal before this device does), the ACBST.BER bit is set. 3. If there is no bus conflict, the ACBST.MASTER and ACBST.SDAST bits are set. 4. If the ACBCTL1.INTEN bit is set, and either the ACBST.BER bit or the ACBST.SDAST bit is set, an interrupt is sent to the ICU. Sending the Address Byte
4. If the requested direction is transmit, and the start transaction was completed successfully (i.e., neither the ACBST.NEGACK nor ACBST.BER bit is set, and no other master has accessed the device), the ACBST.SDAST bit is set to indicate that the module is waiting for service. 5. If the requested direction is receive, the start transaction was completed successfully, and the ACBCTL1.STASTRE bit is clear, the module starts receiving the first byte automatically. 6. Check that both the ACBST.BER and ACBST.NEGACK bits are clear. If the ACBCTL1.INTEN bit is set, an interrupt is generated when either the ACBST.BER or ACBST.NEGACK bit is set. Master Transmit After becoming the bus master, the device can start transmitting data on the ACCESS.bus. To transmit a byte, software must: 1. Check that the BER and NEGACK bits in the ACBST register are clear and the ACBST.SDAST bit is set. Also, if the ACBCTL1.STASTRE bit is set, check that the ACBST.STASTR bit is clear. 2. Write the data byte to be transmitted to the ACBSDA register. When the slave responds with a negative acknowledge, the ACBST.NEGACK bit is set and the ACBST.SDAST bit remains cleared. In this case, if the ACBCTL1.INTEN bit is set, an interrupt is sent to the core. Master Receive
After becoming the bus master, the device can start receivOnce this device is the active master of the ACCESS.bus ing data on the ACCESS.bus. To receive a byte, software (ACBST.MASTER = 1), it can send the address on the bus. must: The address should not be this device's own address as specified in the ACBADDR.ADDR field if the ACBAD- 1. Check that the ACBST.SDAST bit is set and the ACBST.BER bit is clear. Also, if the ACBCTL1.STASTRE bit DR.SAEN bit is set or the ACBADDR2.ADDR field if the is set, check that the ACBST.STASTR bit is clear. ACBADDR2.SAEN bit is set, nor should it be the global call 2. Set the ACBCTL1.ACK bit, if the next byte is the last address if the ACBST.GCMTCH bit is set. byte that should be read. This causes a negative acTo send the address byte use the following sequence: knowledge to be sent. 1. Configure the ACBCTL1.INTEN bit according to the de- 3. Read the data byte from the ACBSDA register. sired operation mode. For a receive transaction where software wants only one byte of data, it should set the Master Stop ACBCTL1.ACK bit. If only an address needs to be sent, A Stop Condition may be issued only when this device is the set the ACBCTL1.STASTRE bit. active bus master (ACBST.MASTRER = 1). To end a trans2. Write the address byte (7-bit target device address), action, set the ACBCTL1.STOP bit before clearing the curand the direction bit, to the ACBSDA register. This rent stall bit (i.e., the ACBST.SDAST, ACBST.NEGACK, or causes the module to generate a transaction. At the ACBST.STASTR bit). This causes the module to send a end of this transaction, the acknowledge bit received is Stop Condition immediately, and clear the ACBCTL1.STOP copied to the ACBST.NEGACK bit. During the transac- bit. tion, the SDA and SCL signals are continuously checked for conflict with other devices. If a conflict is detected, the transaction is aborted, the ACBST.BER bit is set, and the ACBST.MASTER bit is cleared. 3. If the ACBCTL1.STASTRE bit is set, and the transaction was successfully completed (i.e., both the ACBST.BER and ACBST.NEGACK bits are cleared), the ACBST.STASTR bit is set. In this case, the ACB stalls any further ACCESS.bus operations (i.e., holds SCL low). If the ACBCTL1.INTE bit is set, it also sends an interrupt to the core. www.national.com 156
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Master Bus Stall The ACB module can stall the ACCESS.bus between transfers while waiting for the core's response. The ACCESS.bus is stalled by holding the SCL signal low after the acknowledge cycle. Note that this is interpreted as the beginning of the following bus operation. Software must make sure that the next operation is prepared before the bit that causes the bus stall is cleared. The bits that can cause a stall in master mode are:
22.2.2
Slave Mode
A slave device waits in Idle mode for a master to initiate a bus transaction. Whenever the ACB is enabled, and it is not acting as a master (i.e., ACBST.MASTER = 0), it acts as a slave device. Once a Start Condition on the bus is detected, this device checks whether the address sent by the current master matches either:
The ACBADDR.ADDR value if the ACBADDR.SAEN bit Negative acknowledge after sending a byte is set. (ACBSTNEGACK = 1). The ACBADDR2.ADDR value if the ACBADDR2.SAEN ACBST.SDAST bit is set. bit is set. If the ACBCTL1.STASTRE bit is set, after a successful The general call address if the ACBCTL1.GCM bit is set. start (ACBST.STASTR = 1). This match is checked even when the ACBST.MASTER bit is set. If a bus conflict (on SDA or SCL) is detected, the Repeated Start ACBST.BER bit is set, the ACBST.MASTER bit is cleared, A repeated start is performed when this device is already and this device continues to search the received message the bus master (ACBST.MASTER = 1). In this case, the ACfor a match. If an address match, or a global match, is deCESS.bus is stalled and the ACB waits for the core handling tected: due to: negative acknowledge (ACBST.NEGACK = 1), empty buffer (ACBST.SDAST = 1), or a stop-after-start (ACB- 1. This device asserts its data pin during the acknowledge cycle. ST.STASTR = 1). 2. The ACBCST.MATCH, ACBCST.MATCHAF (or For a repeated start: ACBCST.GCMTCH if it is a global call address match, 1. Set the ACBCTL1.START bit. or ACBCST.ARPMATCH if it is an ARP address), and 2. In master receive mode, read the last data item from ACBST.NMATCH in the ACBCST register are set. If the the ACBSDA register. ACBST.XMIT bit is set (i.e., slave transmit mode), the 3. Follow the address send sequence, as described in ACBST.SDAST bit is set to indicate that the buffer is "Sending the Address Byte" on page 156. empty. 4. If the ACB was waiting for handling due to ACB- 3. If the ACBCTL1.INTEN bit is set, an interrupt is generST.STASTR = 1, clear it only after writing the requested ated if both the INTEN and NMINTE bits in the address and direction to the ACBSDA register. ACBCTL1 register are set. 4. Software then reads the ACBST.XMIT bit to identify the Master Error Detections direction requested by the master device. It clears the The ACB detects illegal Start or Stop Conditions (i.e., a ACBST.NMATCH bit so future byte transfers are identiStart or Stop Condition within the data transfer, or the acfied as data bytes. knowledge cycle) and a conflict on the data lines of the ACCESS.bus. If an illegal action is detected, the BER bit is set, Slave Receive and Transmit and the MASTER mode is exited (the MASTER bit is Slave Receive and Transmit are performed after a match is cleared). detected and the data transfer direction is identified. After a byte transfer, the ACB extends the acknowledge clock until Bus Idle Error Recovery software reads or writes the ACBSDA register. The receive When a request to become the active bus master or a re- and transmit sequence are identical to those used in the start operation fails, the ACBST.BER bit is set to indicate the master routine. error. In some cases, both this device and the other device may identify the failure and leave the bus idle. In this case, Slave Bus Stall the start sequence may not be completed and the AC- When operating as a slave, this device stalls the ACCESS.bus may remain deadlocked. CESS.bus by extending the first clock cycle of a transaction in the following cases: To recover from deadlock, use the following sequence: 1. Clear the ACBST.BER and ACBCST.BB bits. 2. Wait for a time-out period to check that there is no other active master on the bus (i.e., the ACBCST.BB bit remains clear). 3. Disable, and re-enable the ACB to put it in the non-addressed slave mode. 4. At this point, some of the slaves may not identify the bus error. To recover, the ACB becomes the bus master by issuing a Start Condition and sends an address field; then issue a Stop Condition to synchronize all the slaves. -- The ACBST.SDAST bit is set. -- The ACBST.NMATCH, and ACBCTL1.NMINTE bits are set. Slave Error Detections The ACB detects illegal Start and Stop Conditions on the ACCESS.bus (i.e., a Start or Stop Condition within the data transfer or the acknowledge cycle). When an illegal Start or Stop Condition is detected, the BER bit is set and the MATCH and GMATCH bits are cleared, causing the module to be an unaddressed slave.
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Power Down When this device is in Power Save, Idle, or Halt mode, the ACB module is not active but retains its status. If the ACB is enabled (ACBCTL2.ENABLE = 1) on detection of a Start Condition, a wake-up signal is issued to the MIWU module. Use this signal to switch this device to Active mode. The ACB module cannot check the address byte for a match following the start condition that caused the wake-up event for this device. The ACB responds with a negative acknowledge, and the device should resend both the Start Condition and the address after this device has had time to wake up.
22.3.1
ACB Serial Data Register (ACBSDA)
The ACBSDA register is a byte-wide, read/write shift register used to transmit and receive data. The most significant bit is transmitted (received) first and the least significant bit is transmitted (received) last. Reading or writing to the ACBSDA register is allowed when ACBST.SDAST is set; or for repeated starts after setting the START bit. An attempt to access the register in other cases produces unpredictable results. 7 DATA 0
Check that the ACBCST.BUSY bit is inactive before entering Power Save, Idle, or Halt mode. This guarantees that the device does not acknowledge an address sent and stop re22.3.2 sponding later. 22.2.3 SDA and SCL Pins Configuration
ACB Status Register (ACBST)
The SDA and SCL pins are driven as open-drain signals. For more information, see the I/O configuration section. 22.2.4 ACB Clock Frequency Configuration
The ACBST register is a byte-wide, read-only register that maintains current ACB status. At reset, and when the module is disabled, ACBST is cleared.
7 6 5 4 3 2 1 0 The ACB module permits software to set the clock frequen- SLVSTP SDAST BER NEGACK STASTR NMATCH MASTER XMIT cy used for the ACCESS.bus clock. The clock is set by the ACBCTL2.SCLFRQ field. This field determines the SCL clock period used by this device. This clock low period may XMIT The Direction Bit bit is set when the ACB modbe extended by stall periods initiated by the ACB module or ule is currently in master/slave transmit mode. by another ACCESS.bus device. In case of a conflict with Otherwise it is cleared. another bus master, a shorter clock high period may be 0 - Receive mode. forced by the other bus master until the conflict is resolved. 1 - Transmit mode. MASTER The Master bit indicates that the module is 22.3 ACCESS.BUS INTERFACE REGISTERS currently in master mode. It is set when a reThe ACCESS.bus interface uses the registers listed in quest for bus mastership succeeds. It is Table 65. cleared upon arbitration loss (BER is set) or the recognition of a Stop Condition. Table 65 ACCESS.bus Interface Registers 0 - Slave mode. 1 - Master mode. Name Address Description NMATCH The New match bit is set when the address ACB Serial Data byte following a Start Condition, or repeated ACBSDA FF F2A0h Register starts, causes a match or a global-call match. The NMATCH bit is cleared when written with ACBST FF F2A2h ACB Status Register 1. Writing 0 to NMATCH is ignored. If the ACBCTL1.INTEN bit is set, an interrupt is sent ACB Control Status ACBCST FF F2A4h when this bit is set. Register 0 - No match. ACB Control 1 - Match or global-call match. ACBCTL1 FF F2A6h Register 1 STASTR The Stall After Start bit is set by the successful completion of an address sending (i.e., a Start ACB Control ACBCTL2 FF F2AAh Condition sent without a bus error, or negative Register 2 acknowledge), if the ACBCTL1.STASTRE bit is set. This bit is ignored in slave mode. When ACB Control ACBCTL3 FF F2AEh the STASTR bit is set, it stalls the bus by pullRegister 3 ing down the SCL line, and suspends any othACB Own Address er action on the bus (e.g., receives first byte in ACBADDR1 FF F2A8h Register 1 master receive mode). In addition, if the ACBCTL1.INTEN bit is set, it also sends an ACB Own Address ACBADDR2 FF F2ACh interrupt to the core. Writing 1 to the STASTR Register 2 bit clears it. It is also cleared when the module is disabled. Writing 0 to the STASTR bit has no effect. 0 - No stall after start condition. 1 - Stall after successful start. www.national.com 158
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NEGACK
BER
SDAST
SLVSTP
The Negative Acknowledge bit is set by hardware when a transmission is not acknowledged on the ninth clock. (In this case, the SDAST bit is not set.) Writing 1 to NEGACK clears it. It is also cleared when the module is disabled. Writing 0 to the NEGACK bit is ignored. 0 - No transmission not acknowledged condition. 1 - Transmission not acknowledged. The Bus Error bit is set by the hardware when a Start or Stop Condition is detected during data transfer (i.e., Start or Stop Condition during the transfer of bits 2 through 8 and acknowledge cycle), or when an arbitration problem is detected. Writing 1 to the BER bit clears it. It is also cleared when the module is disabled. Writing 0 to the BER bit is ignored. 0 - No bus error occurred. 1 - Bus error occurred. The SDA Status bit indicates that the SDA data register is waiting for data (transmit, as master or slave) or holds data that should be read (receive, as master or slave). This bit is cleared when reading from the ACBSDA register during a receive, or when written to during a transmit. When the ACBCTL1.START bit is set, reading the ACBSDA register does not clear the SDAST bit. This enables the ACB to send a repeated start in master receive mode. 0 - ACB module is not waiting for data transfer. 1 - ACB module is waiting for data to be loaded or unloaded. The Slave Stop bit indicates that a Stop Condition was detected after a slave transfer (i.e., after a slave transfer in which MATCH or GCMATCH is set). Writing 1 to SLVSTP clears it. It is also cleared when the module is disabled. Writing 0 to SLVSTP is ignored. 0 - No stop condition after slave transfer occurred. 1 - Stop condition after slave transfer occurred.
22.3.3
ACB Control Status Register (ACBCST)
The ACBCST register is a byte-wide, read/write register that maintains current ACB status. At reset and when the module is disabled, the non-reserved bits of ACBCST are cleared. 7 6 5 4 3 2 1 0
Reserved TGSCL TSDA GCMTCH MATCH BB BUSY
BUSY
BB
MATCH
The BUSY bit indicates that the ACB module is: Generating a Start Condition In Master mode (ACBST.MASTER is set) In Slave mode (ACBCST.MATCH or ACBCST.GCMTCH is set) In the period between detecting a Start and completing the reception of the address byte. After this, the ACB either becomes not busy or enters slave mode. The BUSY bit is cleared by the completion of any of the above states, and by disabling the module. BUSY is a read only bit. It must always be written with 0. 0 - ACB module is not busy. 1 - ACB module is busy. The Bus Busy bit indicates the bus is busy. It is set when the bus is active (i.e., a low level on either SDA or SCL) or by a Start Condition. It is cleared when the module is disabled, on detection of a Stop Condition, or when writing 1 to this bit. See "Usage Hints" on page 162 for a description of the use of this bit. This bit should be set when either the SDA or SCL signals are low. This is done by sampling the SDA and SCL signals continuously and setting the bit if one of them is low. The bit remains set until cleared by a STOP condition or written with 1. 0 - Bus is not busy. 1 - Bus is busy. The Address Match bit indicates in slave mode when ACBADDR.SAEN is set and the first seven bits of the address byte (the first byte transferred after a Start Condition) matches the 7-bit address in the ACBADDR register, or when ACBADDR2.SAEN is set and the first seven bits of the address byte matches the 7-bit address in the ACBADDR2 register. It is cleared by Start Condition or repeated Start and Stop Condition (including illegal Start or Stop Condition). 0 - No address match occurred. 1 - Address match occurred.
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GCMTCH
TSDA
TGSCL
The Global Call Match bit is set in slave mode when the ACBCTL1.GCMEN bit is set and the address byte (the first byte transferred after a Start Condition) is 00h. It is cleared by a Start Condition or repeated Start and Stop Condition (including illegal Start or Stop Condition). 0 - No global call match occurred. 1 - Global call match occurred. The Test SDA bit samples the state of the SDA signal. This bit can be used while recovering from an error condition in which the SDA signal is constantly pulled low by a slave that went out of sync. This bit is a read-only bit. Data written to it is ignored. The Toggle SCL bit enables toggling the SCL signal during error recovery. When the SDA signal is low, writing 1 to this bit drives the SCL signal high for one cycle. Writing 1 to TGSCL when the SDA signal is high is ignored. The bit is cleared when the clock toggle is completed. 0 - Writing 0 has no effect. 1 - Writing 1 toggles the SDA signal high for one cycle.
22.3.4
ACB Control Register 1 (ACBCTL1)
The ACBCTL1 register is a byte-wide, read/write register that configures and controls the ACB module. At reset and while the module is disabled (ACBCTL2.ENABLE = 0), the ACBCTL1 register is cleared. 7 6 5 4 3 2 1 0
STASTRE NMINTE GCMEN ACK Res. INTEN STOP START
START
STOP
The Start bit is set to generate a Start Condition on the ACCESS.bus. The START bit is cleared when the Start Condition is sent, or upon detection of a Bus Error (ACBST.BER = 1). This bit should be set only when in Master mode, or when requesting Master mode. If this device is not the active master of the bus (ACBST.MASTER = 0), setting the START bit generates a Start Con0dition as soon as the ACCESS.bus is free (ACBCST.BB = 0). An address send sequence should then be performed. If this device is the active master of the bus (ACBST.MASTER = 1), when the START bit is set, a write to the ACBSDA register generates a Start Condition, then the ACBSDA data is transmitted as the slave's address and the requested transfer direction. This case is a repeated Start Condition. It may be used to switch the direction of the data flow between the master and the slave, or to choose another slave device without using a Stop Condition in between. 0 - Writing 0 has no effect. 1 - Writing 1 generates a Start condition. The Stop bit in master mode generates a Stop Condition that completes or aborts the current message transfer. This bit clears itself after the Stop condition is issued. 0 - Writing 0 has no effect. 1 - Writing 1 generates a Stop condition.
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INTEN
ACK
GCMEN
NMINTE
STASTRE
The Interrupt Enable bit controls generating ACB interrupts. When the INTEN bit is cleared ACB interrupt is disabled. When the INTEN bit is set, interrupts are enabled. 0 - ACB interrupts disabled. 1 - ACB interrupts enabled. An interrupt is generated (the interrupt signals to the ICU is high) on any of the following events: An address MATCH is detected (ACBST.NMATCH = 1) and the NMINTE bit is set. A Bus Error occurs (ACBST.BERR = 1). Negative acknowledge after sending a byte (ACBST.NEGACK = 1). An interrupt is generated on acknowledge of each transaction (same as hardware setting the ACBST.SDAST bit). If ACBCTL1.STASTRE = 1, in master mode after a successful start (ACBST.STASTR = 1). Detection of a Stop Condition while in slave receive mode (ACBST.SLVSTP = 1). The Acknowledge bit holds the value this device sends in master or slave mode during the next acknowledge cycle. Setting this bit to 1 instructs the transmitting device to stop sending data, since the receiver either does not need, or cannot receive, any more data. This bit is cleared after the first acknowledge cycle. This bit is ignored when in transmit mode. The Global Call Match Enable bit enables the match of an incoming address byte to the general call address (Start Condition followed by address byte of 00h) while the ACB is in slave mode. When cleared, the ACB does not respond to a global call. 0 - Global call matching disabled. 1 - Global call matching enabled. The New Match Interrupt Enable controls whether ACB interrupts are generated on new matches. Set the NMINTE bit to enable the interrupt on a new match (i.e., when ACBST.NMATCH is set). The interrupt is issued only if the ACBCTL1.INTEN bit is set. 0 - New match interrupts disabled. 1 - New match interrupts enabled. The Stall After Start Enable bit enables the stall after start mechanism. When enabled, the ACB is stalled after the address byte. When the STASTRE bit is clear, the ACBST.STASTR bit is always clear. 0 - No stall after start. 1 - Stall-after-start enabled.
22.3.5
ACB Control Register 2 (ACBCTL2)
The ACBCTL2 register is a byte-wide, read/write register that controls the module and selects the ACB clock rate. At reset, the ACBCTL2 register is cleared. 7 SCLFRQ6:0 1 0 ENABLE
ENABLE
SCLFRQ
The Enable bit controls the ACB module. When this bit is set, the ACB module is enabled. When the Enable bit is clear, the ACB module is disabled, the ACBCTL1, ACBST, and ACBCST registers are cleared, and the clocks are halted. 0 - ACB module disabled. 1 - ACB module enabled. The SCL Frequency field specifies the SCL period (low time and high time) in master mode. The clock low time and high time are defined as follows: tSCLl = tSCLh = 2 x SCLFRQ x tCLK Where tCLK is this device's clock period when in Active mode. The SCLFRQ field may be programmed to values in the range of 0001000b through 1111111b. Using any other value has unpredictable results. ACB Control Register 3 (ACBCTL3)
22.3.6
The ACBCTL3 register is a byte-wide, read/write register that expands the clock prescaler field and enables ARP matches. At reset, the ACBCTL3 register is cleared. 7 Reserved 3 2 ARPMEN 1 0
SCLFRQ8:7
ARPMEN
SCLFRQ
The ARP Match Enable bit enables the matching of an incoming address byte to the SMBus ARP address 110 0001b general call address (Start condition followed by address byte of 00h), while the ACB is in slave mode. 0 - ACB does not respond to ARP addresses. 1 - ARP address matching enabled. The SCL Frequency field specifies the SCL period (low time and high time) in master mode. The ACBCTL3 register provides a 2-bit expansion of this field, with the remaining 7 bits being held in the ACBCTL2 register.
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22.3.7
ACB Own Address Register 1 (ACBADDR1)
22.4
USAGE HINTS
The ACBADDR1 register is a byte-wide, read/write register that holds the module's first ACCESS.bus address. After reset, its value is undefined. 7 SAEN 6 ADDR 0
ADDR
SAEN
The Own Address field holds the first 7-bit ACCESS.bus address of this device. When in slave mode, the first 7 bits received after a Start Condition are compared to this field (first bit received to bit 6, and the last to bit 0). If the address field matches the received data and the SAEN bit is set, a match is detected. The Slave Address Enable bit controls whether address matching is performed in slave mode. When set, the SAEN bit indicates that the ADDR field holds a valid address and enables the match of ADDR to an incoming address byte. When cleared, the ACB does not check for an address match. 0 - Address matching disabled. 1 - Address matching enabled0. ACB Own Address Register 2 (ACBADDR2)
22.3.8
The ACBADDR2 register is a byte-wide, read/write register that holds the module's second ACCESS.bus address. After reset, its value is undefined. 7 SAEN 6 ADDR 0
ADDR
SAEN
The Own Address field holds the second 7-bit ACCESS.bus address of this device. When in slave mode, the first 7 bits received after a Start Condition are compared to this field (first bit received to bit 6, and the last to bit 0). If the address field matches the received data and the SAEN bit is set, a match is detected. The Slave Address Enable bit controls whether address matching is performed in slave mode. When set, the SAEN bit indicates that the ADDR field holds a valid address and enables the match of ADDR to an incoming address byte. When cleared, the ACB does not check for an address match. 0 - Address matching disabled. 1 - Address matching enabled.
When the ACB module is disabled, the ACBCST.BB bit is cleared. After enabling the ACB (ACBCTL2.ENABLE = 1) in systems with more than one master, the bus may be in the middle of a transaction with another device, which is not reflected in the BB bit. There is a need to allow the ACB to synchronize to the bus activity status before issuing a request to become the bus master, to prevent bus errors. Therefore, before issuing a request to become the bus master for the first time, software should check that there is no activity on the bus by checking the BB bit after the bus allowed time-out period. When waking up from power down, before checking the ACBCST.MATCH bit, test the ACBCST.BUSY bit to make sure that the address transaction has finished. The BB bit is intended to solve a deadlock in which two, or more, devices detect a usage conflict on the bus and both devices cease being bus masters at the same time. In this situation, the BB bits of both devices are active (because each deduces that there is another master currently performing a transaction, while in fact no device is executing a transaction), and the bus would stay locked until some device sends a ACBCTL1.STOP condition. The ACBCST.BB bit allows software to monitor bus usage, so it can avoid sending a STOP signal in the middle of the transaction of some other device on the bus. This bit detects whether the bus remains unused over a certain period, while the BB bit is set. In some cases, the bus may get stuck with the SCL or SDA lines active. A possible cause is an erroneous Start or Stop Condition that occurs in the middle of a slave receive session. When the SCL signal is stuck active, there is nothing that can be done, and it is the responsibility of the module that holds the bus to release it. When the SDA signal is stuck active, the ACB module enables the release of the bus by using the following sequence. Note that in normal cases, the SCL signal may be toggled only by the bus master. This protocol is a recovery scheme which is an exception that should be used only in the case when there is no other master on the bus. The recovery scheme is as follows: 1. Disable and re-enable the module to set it into the not addressed slave mode. 2. Set the ACBCTL1.START bit to make an attempt to issue a Start Condition. 3. Check if the SDA signal is active (low) by reading ACBCST.TSDA bit. If it is active, issue a single SCL cycle by writing 1 to ACBCST.TGSCL bit. If the SDA line is not active, continue from step 5. 4. Check if the ACBST.MASTER bit is set, which indicates that the Start Condition was sent. If not, repeat step 3 and 4 until the SDA signal is released. 5. Clear the BB bit. This enables the START bit to be executed. Continue according to "Bus Idle Error Recovery" on page 157.
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22.4.1
Avoiding Bus Error During Write Transaction address is successfully sent and before writing to the ACBSDA register. This has the effect of forcing SCL into the stretch state. The following code example is the relevant segment of the ACCESS.bus driver addressing this issue.
A Bus Error (BER) may occur during a write transaction if the data register is written at a very specific time. The module generates one system-clock cycle setup time of SDA to SCL vs. the minimum time of the clock divider ratio. The problem can be masked within the driver by dynamically dividing-by-half the SCL width immediately after the slave
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ; NAME: ACBRead Reads "Count" byte(s) from selected I2C Slave. If read address differs from previous ; Read or Write operation (as recorded in NextAddress), a "dummy" write transaction is ; initiated to reset the address to the desired location. This is followed by a repeated ; Start sequence and the Read transaction. All transactions begin with a call to ACBStartX ; which sends the Start condition and Slave address. Checks for errors throughout process. ; ; PARAMETERS: UBYTE Slave Slave Device Address. Must be of format 0xXXXX0000 ; UWORD Addrs Byte/Array address (extended addressing mode uses two byte address) ; UWORD Count Number of bytes to read ; UBYTE *buf Pointer to receive buffer ; ; CALLS: ACBStartX ; ; RETURNED: error status ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/ UWORD ACBRead (UBYTE Slave, UWORD Addrs, UWORD Count, UBYTE *buf) { ACB_T *acb; UBYTE err, *rcv; UWORD Timeout; acb = (ACB_T*)ACB_ADDRESS; /* Set pointer to ACB module /* If the indicated address differs from the last /* recorded access (i.e. Random Read), we must first /* send a "dummy" write to the desired new address.. /* Update last address placeholder */ */ */ */ */
if (Addrs != NextAddress) { NextAddress = KeyInit(); KBD_OUT &= ~BIT0; /* Send start bit and Slave address... if ((err = ACBStartX (Slave | (Addrs >> 7 & 0x0E), ACB_WRITE, 0))) return (err); // KBD_OUT &= ~BIT0; acb->ACBsda = KBD_OUT &= ~BIT0; Timeout = /* Set timeout /* Wait for xmitter to be ready...zzzzzzzzz while (!(acb->ACBst & ACBSDAST) && !(acb->ACBst & ACBBER) && Timeout--); if (acb->ACBst & ACBBER) { acb->ACBst } KBD_OUT &= ~BIT0; if (!Timeout) return (ACBERR_TIMEOUT); } /* (Re)Send start bit and Slave address... if ((err = ACBStartX (Slave | (Addrs >> 7 & 0x0E), ACB_READ, Count))) /* If error, return return (err); rcv = buf; /* Get address of read buffer /* Read Count bytes into user's buffer /* If this the final byte, or only one requested, send /* the NACK bit after reception /* Set timeout */ */ */ */ */ */ */ /* If we timeout, return error */ |= ACBBER; /* If a bus error occurs while sending address, clear /* the error flag and return error status */ */ 1000; */ */ (UBYTE)Addrs; /* Send new address byte */ /* If unsuccessful, return error code */ */ Addrs;
return (ACBERR_COLLISION);
while (Count) { if (Count-- == 1) acb->ACBctl1 Timeout = 1000; |= ACBACK;
while (!(acb->ACBst & ACBSDAST) && Timeout--); if (!Timeout) return (ACBERR_TIMEOUT); *rcv++ } = acb->ACBsda; /* NO - Read byte from Recv register /* Adjust current address placeholder */ */ /* Timed out?? /* YES - return error */ */
NextAddress++;
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acb->ACBctl1 }
|=
ACBSTOP;
/* Send STOP bit /* Return success status....
*/ */
return (ACB_NOERR); /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ; NAME: ACBStartX Initiates an ACB bus transaction by sending the Start bit, followed by the Slave address ; and R/W flag. Checks for any ACB errors throughout this sequence and returns status. ; ; PARAMETERS: UBYTE Slave I2C address of Slave device ; UBYTE R_nW Read/Write flag (0x01 or 0x00) ; UWORD Count Desired number of bytes (read/write) ; ; CALLS: ; ; RETURNED: error/success ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/ UWORD ACBStartX (UBYTE Slave, UBYTE R_nW, UWORD Count) { ACB_T *acb; UWORD Timeout; /* Get address of ACB module acb = (ACB_T*)ACB_ADDRESS; /* If Bus is Busy and we're NOT the Master, return err if (acb->ACBcst & ACBBB && !(acb->ACBst & ACBMASTER)) return (ACBERR_NOTMASTER); /* If we're good to go, send Start condition acb->ACBctl1 |= ACBSTART; /* Check if we're the Bus Master with timeout Timeout = 100; while (!(acb->ACBst & ACBSDAST) && Timeout--) { if (acb->ACBst & ACBBER) { acb->ACBst } } if (!Timeout) return (ACBERR_NOTMASTER); acb->ACBsda = Timeout = Slave | R_nW; /* If timeout, we must NOT be the Master...signal error */ /* Now, send the address and R/W flag... /* Send address and R/W flag /* Failsafe for lockup /* Wait for address to be sent and ACK'd */ */ */ */ |= ACBBER; /* Related to bus error problem /* If collision occurs, clear error and return status
*/ */ */ */ */ */
return (ACBERR_COLLISION);
1000;
while (!(acb->ACBst & ACBSDAST) && !(acb->ACBst & ACBNEGACK)&& --Timeout) { if (acb->ACBst & ACBBER) { acb->ACBst |= ACBBER; return (ACBERR_COLLISION); } } KBD_OUT |= BIT0; // OScope marker if (!Timeout) return (ACBERR_TIMEOUT); else if (acb->ACBst & ACBNEGACK) return (ACBERR_NEGACK); /* Otherwise return success else { return (ACB_NOERR); } */ /* If timeout, signal error /* Or if Slave does not reply, report busy/error */ */ /* If a bus error occurs while sending address, clear /* the error flag and return error status */ */
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23.0 Timing and Watchdog Module
The Timing and Watchdog Module (TWM) generates the clocks and interrupts used for timing periodic functions in the system; it also provides Watchdog protection over software execution. The TWM is designed to provide flexibility in system design by configuring various clock ratios and by selecting the Watchdog clock source. After setting the TWM configuration, software can lock it for a higher level of protection against erroneous software action. Once the TWM is locked, only reset can release it. Slow Clock period. The prescaled clock signal is called T0IN.
23.2
TIMER T0 OPERATION
Timer T0 is a programmable 16-bit down counter that can be used as the time base for real-time operations such as a periodic audible tick. It can also be used to drive the Watchdog circuit. The timer starts counting from the value loaded into the TWMT0 register and counts down on each rising edge of T0IN. When the timer reaches zero, it is automatically reloaded from the TWMT0 register and continues counting down from that value. Therefore, the frequency of the timer is: fSLCLK fTIMER = ---------------------------------------------------------------------( TWTM0 + 1 ) x prescaler When an external crystal oscillator is used as the SLCLK source or when the fast clock is divided accordingly, fSLCLK is 32.768 kHz. The value stored in TWMT0 can range from 0001h to FFFFh.
23.1
TWM STRUCTURE
Figure 78 is a block diagram showing the internal structure of the Timing and Watchdog module. There are two main sections: the Real-Time Timer (T0) section at the top and the Watchdog section on the bottom. All counting activities of the module are based on the Slow Clock (SLCLK). A prescaler counter divides this clock to make a slower clock. The prescaler factor is defined by a 3bit field in the Timer and Watchdog Prescaler register, which selects either 1, 2, 4, 8, 16, or 32 as the divisor. Therefore, the prescaled clock period can be 2, 4, 8, 16, or 32 times the
REAL TIME TIMER (T0) Slow Clock 5-Bit Prescaler Counter (TWCP) T0IN
TWW/MT0 Register
T0CSR Contrl. Reg.
T0LINT (to ICU)
Restart 16-Bit Timer (Timer0) Underflow T0OUT (to Multi-InputWake-Up)
WATCHDOG Timer
Underflow
Restart
WATCHDOG Service Logic
WDSDM WDCNT
Watchdog Error WATCHDOG
WDERR DS080
Figure 78. Timing and Watchdog Module Block Diagram When the counter reaches zero, an internal timer signal called T0OUT is set for one T0IN clock cycle. This signal sets the TC bit in the TWMT0 Control and Status Register (T0CSR). It also generates an interrupt (IRQ14), when enabled by the T0CSR.T0INTE bit. T0OUT is also an input to the MIWU (see Section 13.0), so an edge-triggered interrupt is also available through this alternative mechanism. If software loads the TWMT0 register with a new value, the timer uses that value the next time that it reloads the 16-bit timer register (in other words, after reaching zero). Software can restart the timer at any time (on the very next edge of the T0IN clock) by setting the Restart (RST) bit in the T0CSR register. The T0CSR.RST bit is cleared automatically upon restart of the 16-bit timer. Note: To enter Power Save or Idle mode after setting the T0CSR.RST bit, software must wait for the reset operation to complete before performing the switch.
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23.3
WATCHDOG OPERATION
23.3.2
Power Save Mode Operation
The Watchdog is an 8-bit down counter that operates on the rising edge of a specified clock source. At reset, the Watchdog is disabled; it does not count and no Watchdog signal is generated. A write to either the Watchdog Count (WDCNT) register or the Watchdog Service Data Match (WDSDM) register starts the counter. The Watchdog counter counts down from the value programmed in the WDCNT register. Once started, only a reset can stop the Watchdog from operating. The Watchdog can be programmed to use either T0OUT or T0IN as its clock source (the output and input of Timer T0, respectively). The TWCFG.WDCT0I bit controls this clock selection. Software must periodically "service" the Watchdog. There are two ways to service the Watchdog, the choice depending on the programmed value of the WDSDME bit in the Timer and Watchdog Configuration (TWCFG) register. If the TWCFG.WDSDME bit is clear, the Watchdog is serviced by writing a value to the WDCNT register. The value written to the register is reloaded into the Watchdog counter. The counter then continues counting down from that value. If the TWCFG.WDSDME bit is set, the Watchdog is serviced by writing the value 5Ch to the Watchdog Service Data Match (WDSDM) register. This reloads the Watchdog counter with the value previously programmed into the WDCNT register. The counter then continues counting down from that value. A Watchdog error signal is generated by any of the following events: The Watchdog serviced too late. The Watchdog serviced too often. The WDSDM register is written with a value other than 5Ch when WDSDM type servicing is enabled (TWCFG.WDSDME = 1). A Watchdog error condition resets the device. 23.3.1 Register Locking
The Timer and Watchdog Module is active in both the Power Save and Idle modes. The clocks and counters continue to operate normally in these modes. The WDSDM register is accessible in the Power Save and Idle modes, but the other TWM registers are accessible only in the Active mode. Therefore, Watchdog servicing must be carried out using the WDSDM register in the Power Save or Idle mode. In the Halt mode, the entire device is frozen, including the Timer and Watchdog Module. On return to Active mode, operation of the module resumes at the point at which it was stopped. Note: After a restart or Watchdog service through WDCNT, do not enter Power Save mode for a period equivalent to 5 Slow Clock cycles.
23.4
TWM REGISTERS
The TWM registers controls the operation of the Timing and Watchdog Module. There are six such registers: Table 66 TWM Registers Name TWCFG Address FF FF20h Description Timer and Watchdog Configuration Register Timer and Watchdog Clock Prescaler Register TWM Timer 0 Register TWMT0 Control and Status Register Watchdog Count Register Watchdog Service Data Match Register
TWCP TWMT0 T0CSR WDCNT WDSDM
FF FF22h FF FF24h FF FF26h FF FF28h FF FF2Ah
The Timer and Watchdog Configuration (TWCFG) register is used to set the Watchdog configuration. It controls the The WDSDM register is accessible in both Active and PowWatchdog clock source (T0IN or T0OUT), the type of er Save mode. The other TWM registers are accessible only Watchdog servicing (using WDCNT or WDSDM), and the in Active mode. locking state of the TWCFG, TWCPR, TIMER0, T0CSR, and WDCNT registers. A register that is locked cannot be read or written. A write operation is ignored and a read operation returns unpredictable results. If the TWCFG register is itself locked, it remains locked until the device is reset. Any other locked registers also remain locked until the device is reset. This feature prevents a runaway program from tampering with the programmed Watchdog function.
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23.4.1
Timer and Watchdog Configuration Register (TWCFG)
23.4.2
Timer and Watchdog Clock Prescaler Register (TWCP)
The TWCFG register is a byte-wide, read/write register that selects the Watchdog clock input and service method, and also allows the Watchdog registers to be selectively locked. A locked register cannot be read or written; a read operation returns unpredictable values and a write operation is ignored. Once a lock bit is set, that bit cannot be cleared until the device is reset. At reset, the non-reserved bits of the register are cleared. The register format is shown below. 76 5 4 3 2 1 0
The TWCP register is a byte-wide, read/write register that specifies the prescaler value used for dividing the low-frequency clock to generate the T0IN clock. At reset, the nonreserved bits of the register are cleared. The register format is shown below. 7 Reserved 3 2 MDIV 0
Res. WDSDME WDCT0I LWDCNT LTWMT0 LTWCP LTWCFG
MDIV
LTWCFG
LTWCP
LTWMT0
LWDCNT
WDCT0I
WDSDME
The Lock TWCFG Register bit controls access to the TWCFG register. When clear, access to the TWCFG register is allowed. When set, the TWCFG register is locked. 0 - TWCFG register unlocked. 1 - TWCFG register locked. The Lock TWCP Register bit controls access to the TWCP register. When clear, access to the TWCP register is allowed. When set, the TWCP register is locked. 0 - TWCP register unlocked. 1 - TWCP register locked. The Lock TWMT0 Register bit controls access to the TWMT0 register. When clear, access to the TWMT0 and T0CSR registers are allowed. When set, the TWMT0 and T0CSR registers are locked. 0 - TWMT0 register unlocked. 1 - TWMT0 register locked. The Lock LDWCNT Register bit controls access to the LDWCNT register. When clear, access to the LDWCNT register is allowed. When set, the LDWCNT register is locked. 0 - LDWCNT register unlocked. 1 - LDWCNT register locked. The Watchdog Clock from T0IN bit selects the clock source for the Watchdog timer. When clear, the T0OUT signal (the output of Timer T0) is used as the Watchdog clock. When set, the T0IN signal (the prescaled Slow Clock) is used as the Watchdog clock. 0 - Watchdog timer is clocked by T0OUT. 1 - Watchdog timer is clocked by T0IN. The Watchdog Service Data Match Enable bit controls which method is used to service the Watchdog timer. When clear, Watchdog servicing is accomplished by writing a count value to the WDCNT register; write operations to the Watchdog Service Data Match (WDSDM) register are ignored. When set, Watchdog servicing is accomplished by writing the value 5Ch to the WDSDM register. 0 - Write a count value to the WDCNT register to service the Watchdog timer. 1 - Write 5Ch to the WDSDM register to service the Watchdog timer.
Main Clock Divide. This 3-bit field defines the prescaler factor used for dividing the low speed device clock to create the T0IN clock. The allowed 3-bit values and the corresponding clock divisors and clock rates are listed below. MDIV 000 001 010 011 100 101 Other Clock Divisor (fSCLK = 32.768 kHz) 1 2 4 8 16 32 Reserved T0IN Frequency 32.768 kHz 16.384 kHz 8.192 kHz 4.096 kHz 2.056 kHz 1.024 kHz N/A
23.4.3
TWM Timer 0 Register (TWMT0)
The TWMT0 register is a word-wide, read/write register that defines the T0OUT interrupt rate. At reset, TWMT0 register is initialized to FFFFh. The register format is shown below. 15 PRESET 0
PRESET
The Timer T0 Preset field holds the value used to reload Timer T0 on each underflow. Therefore, the frequency of the Timer T0 interrupt is the frequency of T0IN divided by (PRESET+1). The allowed values of PRESET are 0001h through FFFFh.
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23.4.4
TWMT0 Control and Status Register (T0CSR)
23.4.5
Watchdog Count Register (WDCNT)
The T0CSR register is a byte-wide, read/write register that controls Timer T0 and shows its current status. At reset, the non-reserved bits of the register are cleared. The register format is shown below. 7 5 4 3 2 T0INTE 1 TC 0 RST
The WDCNT register is a byte-wide, write-only register that holds the value that is loaded into the Watchdog counter each time the Watchdog is serviced. The Watchdog is started by the first write to this register. Each successive write to this register restarts the Watchdog count with the written value. At reset, this register is initialized to 0Fh. 7 PRESET 0
Reserved
FRZT0E WDLTD
RST
TC
T0INTE
WDLTD
FRZT0E
The Restart bit is used to reset Timer T0. When this bit is set, it forces the timer to reload the value in the TWMT0 register on the next rising edge of the selected input clock. The RST bit is reset automatically by the hardware on the same rising edge of the selected input clock. Writing a 0 to this bit position has no effect. At reset, the non-reserved bits of the register are cleared. 0 - Writing 0 has no effect. 1 - Writing 1 resets Timer T0. The Terminal Count bit is set by hardware when the Timer T0 count reaches zero and is cleared when software reads the T0CSR register. It is a read-only bit. Any data written to this bit position is ignored. The TC bit is not cleared if FREEZE mode is asserted by an external debugging system. 0 - Timer T0 did not count down to 0. 1 - Timer T0 counted down to 0. The Timer T0 Interrupt Enable bit enables an interrupt to the CPU each time the Timer T0 count reaches zero. When this bit is clear, Timer T0 interrupts are disabled. 0 - Timer T0 interrupts disabled. 1 - Timer T0 interrupts enabled. The Watchdog Last Touch Delay bit is set when either WDCNT or WDSDM is written and the data transfer to the Watchdog is in progress (see WDCNT and WDSDM register description). When clear, it is safe to switch to Power Save mode. 0 - No data transfer to the Watchdog is in progress, safe to enter Power Save mode. 1 - Data transfer to the Watchdog in progress. The Freeze Timer0 Enable bit controls whether TImer 0 is stopped in FREEZE mode. If this bit is set, the Timer 0 is frozen (stopped) when the FREEZE input to the TWM is asserted. If the FRZT0E bit is clear, only the Watchdog timer is frozen by asserting the FREEZE input signal. After reset, this bit is clear. 0 - Timer T0 unaffected by FREEZE mode. 1 - Timer T0 stopped in FREEZE mode.
23.4.6
Watchdog Service Data Match Register (WDSDM)
The WSDSM register is a byte-wide, write-only register used for servicing the Watchdog. When this type of servicing is enabled (TWCFG.WDSDME = 1), the Watchdog is serviced by writing the value 5Ch to the WSDSM register. Each such servicing reloads the Watchdog counter with the value previously written to the WDCNT register. Writing any data other than 5Ch triggers a Watchdog error. Writing to the register more than once in one Watchdog clock cycle also triggers a Watchdog error signal. If this type of servicing is disabled (TWCFG.WDSDME = 0), any write to the WSDSM register is ignored. 7 RSTDATA 0
23.5
WATCHDOG PROGRAMMING PROCEDURE
The highest level of protection against software errors is achieved by programming and then locking the Watchdog registers and using the WDSDM register for servicing. This is the procedure: 1. Write the desired values into the TWM Clock Prescaler register (TWCP) and the TWM Timer 0 register (TWMT0) to control the T0IN and T0OUT clock rates. The frequency of T0IN can be programmed to any of six frequencies ranging from 1/32 x fSLCLK to fSLCLK. The frequency of T0OUT is equal to the frequency of T0IN divided by (1+ PRESET), in which PRESET is the value written to the TWMT0 register. 2. Configure the Watchdog clock to use either T0IN or T0OUT by setting or clearing the TWCFG.WDCT0I bit. 3. Write the initial value into the WDCNT register. This starts operation of the Watchdog and specifies the maximum allowed number of Watchdog clock cycles between service operations. 4. Set the T0CSR.RST bit to restart the TWMT0 timer. 5. Lock the Watchdog registers and enable the Watchdog Service Data Match Enable function by setting bits 0, 1, 2, 3, and 5 in the TWCFG register. 6. Service the Watchdog by periodically writing the value 5Ch to the WDSDM register at an appropriate rate. Servicing must occur at least once per period programmed into the WDCNT register, but no more than once in a single Watchdog input clock cycle.
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CP3CN23
24.0 Multi-Function Timer
The Multi-Function Timer module contains a pair of 16-bit timer/counters. Each timer/counter unit offers a choice of clock sources for operation and can be configured to operate in any of the following modes: Processor-Independent Pulse Width Modulation (PWM) mode, which generates pulses of a specified width and duty cycle, and which also provides a general-purpose timer/counter. Dual-Input Capture mode, which measures the elapsed time between occurrences of external events, and which also provides a general-purpose timer/counter. Dual Independent Timer mode, which generates system timing signals or counts occurrences of external events. Single-Input Capture and Single Timer mode, which provides one external event counter and one system timer. The timer unit uses two I/O pins, called TA and TB. The timer I/O pins are alternate functions of the PG7 and PE4 port pins, respectively.
24.1
TIMER STRUCTURE
Figure 79 is a block diagram showing the internal structure of the MFT. There are two main functional blocks: a Timer/ Counter and Action block and a Clock Source block. The Timer/Counter and Action block contains two separate timer/counter units, called Timer/Counter 1 and Timer/Counter 2.
Clock Source Clock Prescaler/Selector
Timer/Counter Reload/Capture A TCRA Timer/Counter 1 TCNT1 Reload/Capture B TCRB Timer/Counter 2 TCNT2
Action
Toggle/Capture/Interrupt
TA Interrupt A Interrupt B
System Clock
TB
External Event
PWM/Capture/Counter Mode Select + Control
DS081
Figure 79. Multi-Function Timer Block Diagram 24.1.1 Timer/Counter Block In a power-saving mode that uses the low-frequency (32.768 kHz) clock as the System Clock, the synchronization circuit requires that the Slow Clock operate at no more than one-fourth the speed of the 32.768 kHz System Clock. 24.1.2 Clock Source Block
The Timer/Counter block contains the following functional blocks: Two 16-bit counters, Timer/Counter 1 (TCNT1) and Timer/Counter 2 (TCNT2) Two 16-bit reload/capture registers, TCRA and TCRB Control logic necessary to configure the timer to operate in any of the four operating modes Interrupt control and I/O control logic
The Clock Source block generates the signals used to clock the two timer/counter registers. The internal structure of the Clock Source block is shown in Figure 80.
Prescaler Register TPRSC
No Clock Counter 1 Clock Select Prescaled Clock Counter 1 Clock
Reset System Clock
5-Bit Prescaler Counter
Pulse Accumulator
TB
Synchr.
External Event
Counter 2 Clock Select
Counter 2 Clock DS082
Figure 80.
Multi-Function Timer Clock Source
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CP3CN23
Counter Clock Source Select
External Event Clock
There are two clock source selectors that allow software to The TB I/O pin can be configured to operate as an external independently select the clock source for each of the two event input clock for either of the two 16-bit counters. This 16-bit counters from any one of the following sources: input can be programmed to detect either rising or falling edges. The minimum pulse width of the external signal is No clock (which stops the counter) one System Clock cycle. This means that the maximum frePrescaled System Clock quency at which the counter can run in this mode is one-half External event count based on TB of the System Clock frequency. This clock source is not Pulse accumulate mode based on TB Slow Clock (derived from the low-frequency oscillator or available in the capture modes (modes 2 and 4) because the TB pin is used as one of the two capture inputs. divided from the high-speed oscillator) Prescaler The 5-bit clock prescaler allows software to run the timer with a prescaled clock signal. The prescaler consists of a 5bit read/write prescaler register (TPRSC) and a 5-bit down counter. The System Clock is divided by the value contained in the prescaler register plus 1. Therefore, the timer clock period can be set to any value from 1 to 32 divisions of the System Clock period. The prescaler register and down counter are both cleared upon reset. Pulse Accumulate Mode The counter can also be configured to count prescaler output clock pulses when the TB input is high and not count when the TB input is low, as illustrated in Figure 81. The resulting count is an indicator of the cumulative time that the TB input is high. This is called the "pulse-accumulate" mode. In this mode, an AND gate generates a clock signal for the counter whenever a prescaler clock pulse is generated and the TB input is high. (The polarity of the TB signal is programmable, so the counter can count when the TB input is low rather than high.) The pulse-accumulate mode is not available in the capture modes (modes 2 and 4) because the TB pin is used as one of the two capture inputs.
Prescaler Output
TB
Counter Clock
DS083
Figure 81. Slow Clock
Pulse-Accumulate Mode Idle and Halt modes stop the System Clock (the high-frequency and/or low-frequency clock) completely. If the System Clock is stopped, the timer stops counting until the System Clock resumes operation. In the Idle or Halt mode, the System Clock stops completely, which stops the operation of the timers. In that case, the timers stop counting until the System Clock resumes operation.
The Slow Clock is generated by the Triple Clock and Reset module. The clock source is either the divided fast clock or the external 32.768 kHz crystal oscillator (if available and selected). The Slow Clock can be used as the clock source for the two 16-bit counters. Because the Slow Clock can be asynchronous to the System Clock, a circuit is provided to synchronize the clock signal to the high-frequency System Clock before it is used for clocking the counters. The synchronization circuit requires that the Slow Clock operate at no more than one-fourth the speed of the System Clock. Limitations in Low-Power Modes The Power Save mode uses the Slow Clock as the System Clock. In this mode, the Slow Clock cannot be used as a clock source for the timers because that would drive both clocks at the same frequency, and the clock ratio needed for synchronization to the System Clock would not be maintained. However, the External Event Clock and Pulse Accumulate Mode will still work, as long as the external event pulses are at least the size of the whole slow-clock period. Using the prescaled System Clock will also work, but at a much slower rate than the original System Clock.
24.2
TIMER OPERATING MODES
Each timer/counter unit can be configured to operate in any of the following modes: Processor-Independent Pulse Width Modulation (PWM) mode Dual-Input Capture mode Dual Independent Timer mode Single-Input Capture and Single Timer mode At reset, the timers are disabled. To configure and start the timers, software must write a set of values to the registers that control the timers. The registers are described in Section 24.5.
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24.2.1
The timer can be configured to toggle the TA output bit on Mode 1 is the Processor-Independent Pulse Width Modula- each underflow. This generates a clock signal on the TA outtion (PWM) mode, which generates pulses of a specified put with the width and duty cycle determined by the values width and duty cycle, and which also provides a separate stored in the TCRA and TCRB registers. This is a "processor-independent" PWM clock because once the timer is set general-purpose timer/counter. up, no more action is required from the CPU to generate a Figure 82 is a block diagram of the Multi-Function Timer continuous PWM signal. configured to operate in Mode 1. Timer/Counter 1 (TCNT1) functions as the time base for the PWM timer. It counts The timer can be configured to generate separate interrupts down at the clock rate selected for the counter. When an un- upon reload from the TCRA and TCRB registers. The interderflow occurs, the timer register is reloaded alternately rupts can be enabled or disabled under software control. from the TCRA and TCRB registers, and counting proceeds The CPU can determine the cause of each interrupt by looking at the TAPND and TBPND bits, which are updated by downward from the loaded value. the hardware on each occurrence of a timer reload. On the first underflow, the timer is loaded from the TCRA register, then from the TCRB register on the next underflow, In Mode 1, Timer/Counter 2 (TCNT2) can be used either as then from the TCRA register again on the next underflow, a simple system timer, an external event counter, or a pulseand so on. Every time the counter is stopped and restarted, accumulate counter. The clock counts down using the clock it always obtains its first reload value from the TCRA regis- selected with the Timer/Counter 2 clock selector. It generter. This is true whether the timer is restarted upon reset, af- ates an interrupt upon each underflow if the interrupt is enter entering Mode 1 from another mode, or after stopping abled with the TDIEN bit. and restarting the clock with the Timer/Counter 1 clock selector.
Mode 1: Processor-Independent PWM
Reload A = Time 1 TCRA
TAPND
Underflow TAIEN Timer 1 Clock Timer/Counter 1 TCNT1 TAEN Underflow TBIEN Reload B = Time 2 TCRB TBPND
Timer Interrupt A
TA
Timer Interrupt B
Timer 2 Clock
Timer/Counter 2 TCNT2 TDIEN TDPND
Timer Interrupt D
Clock Selector
TB DS084
Figure 82.
Processor-Independent PWM Mode
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24.2.2
The values captured in the TCRA register at different times Mode 2 is the Dual Input Capture mode, which measures reflect the elapsed time between transitions on the TA pin. the elapsed time between occurrences of external events, The same is true for the TCRB register and the TB pin. The and which also provides a separate general-purpose timer/ input signal on the TA or TB pin must have a pulse width equal to or greater than one System Clock cycle. counter. Figure 83 is a block diagram of the Multi-Function Timer configured to operate in Mode 2. The time base of the capture timer depends on Timer/Counter 1, which counts down using the clock selected with the Timer/Counter 1 clock selector. The TA and TB pins function as capture inputs. A transition received on the TA pin transfers the timer contents to the TCRA register. Similarly, a transition received on the TB pin transfers the timer contents to the TCRB register. Each input pin can be configured to sense either rising or falling edges. The TA and TB inputs can be configured to preset the counter to FFFFh on reception of a valid capture event. In this case, the current value of the counter is transferred to the corresponding capture register and then the counter is preset to FFFFh. Using this approach allows software to determine the on-time and off-time and period of an external signal with a minimum of CPU overhead. There are three separate interrupts associated with the capture timer, each with its own enable bit and pending bit. The three interrupt events are reception of a transition on the TA pin, reception of a transition on the TB pin, and underflow of the TCNT1 counter. The enable bits for these events are TAIEN, TBIEN, and TCIEN, respectively. In Mode 2, Timer/Counter 2 (TCNT2) can be used as a simple system timer. The clock counts down using the clock selected with the Timer/Counter 2 clock selector. It generates an interrupt upon each underflow if the interrupt is enabled with the TDIEN bit. Neither Timer/Counter 1 (TCNT1) nor Timer/Counter 2 (TCNT2) can be configured to operate as an external event counter or to operate in the pulse-accumulate mode because the TB input is used as a capture input. Attempting to select one of these configurations will cause one or both counters to stop.
Mode 2: Dual Input Capture
Timer Interrupt 1 TAIEN TAPND Capture A TCRA Preset TAEN Timer 1 Clock Timer/Counter 1 TCNT1 Underflow Preset TBEN TB TBPND Timer Interrupt 1 TBIEN TCIEN TA
TCPND Timer Interrupt 1
Capture B TCRB
TDPND Timer 2 Clock Timer/Counter 2 TnCNT2 Underflow TDIEN Timer Interrupt 2 DS085
Figure 83. Dual-Input Capture Mode
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CP3CN23
24.2.3
Mode 3: Dual Independent Timer/Counter
Mode 3 is the Dual Independent Timer mode, which generates system timing signals or counts occurrences of external events. Figure 84 is a block diagram of the Multi-Function Timer configured to operate in Mode 3. The timer is configured to operate as a dual independent system timer or dual external event counter. In addition, Timer/Counter 1 can generate a 50% duty cycle PWM signal on the TA pin. The TB pin can be used as an external event input or pulse-accumulate input and can be used as the clock source for either Timer/ Counter 1 or Timer/Counter 2. Both counters can also be clocked by the prescaled System Clock. Timer/Counter 1 (TCNT1) counts down at the rate of the selected clock. On underflow, it is reloaded from the TCRA register and counting proceeds down from the reloaded val-
ue. In addition, the TA pin is toggled on each underflow if this function is enabled by the TAEN bit. The initial state of the TA pin is software-programmable. When the TA pin is toggled from low to high, it sets the TCPND interrupt pending bit and also generates an interrupt if enabled by the TAIEN bit. Because the TA pin toggles on every underflow, a 50% duty cycle PWM signal can be generated on the TA pin without any further action from the CPU. Timer/Counter 2 (TCNT2) counts down at the rate of the selected clock. On underflow, it is reloaded from the TCRB register and counting proceeds down from the reloaded value. In addition, each underflow sets the TDPND interrupt pending bit and generates an interrupt if the interrupt is enabled by the TDIEN bit.
Reload A TCRA
TAPND
Underflow TAIEN Timer 1 Clock Timer/Counter 1 TCNT1 TAEN Reload B TCRB
Timer Interrupt 1
TA
Underflow TDIEN Timer 2 Clock Timer/Counter 2 TCNT2 TDPND
Timer Interrupt 2
Clock Selector
TB DS086
Figure 84. Dual-Independent Timer/Counter Mode
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24.2.4
Mode 4: Input Capture Plus Timer
Mode 4 is the Single Input Capture and Single Timer mode, which provides one external event counter and one system timer. Figure 85 is a block diagram of the Multi-Function Timer configured to operate in Mode 4. This mode offers a combination of Mode 3 and Mode 2 functions. Timer/Counter 1 is used as a system timer as in Mode 3 and Timer/Counter 2 is used as a capture timer as in Mode 2, but with a single input rather than two inputs. Timer/Counter 1 (TCNT1) operates the same as in Mode 3. It counts down at the rate of the selected clock. On underflow, it is reloaded from the TCRA register and counting proceeds down from the reloaded value. The TA pin is toggled on each underflow, when this function is enabled by the TAEN bit. When the TA pin is toggled from low to high, it sets the TCPND interrupt pending bit and also generates an interrupt if the interrupt is enabled by the TAIEN bit. A 50% duty cycle PWM signal can be generated on TA without any further action from the CPU. Timer/Counter 2 (TCNT1) counts down at the rate of the selected clock. The TB pin functions as the capture input. A transition received on TB transfers the timer contents to the
TCRB register. The input pin can be configured to sense either rising or falling edges. The TB input can be configured to preset the counter to FFFFh on reception of a valid capture event. In this case, the current value of the counter is transferred to the capture register and then the counter is preset to FFFFh. The values captured in the TCRB register at different times reflect the elapsed time between transitions on the TA pin. The input signal on TB must have a pulse width equal to or greater than one System Clock cycle. There are two separate interrupts associated with the capture timer, each with its own enable bit and pending bit. The two interrupt events are reception of a transition on TB and underflow of the TCNT2 counter. The enable bits for these events are TBIEN and TDIEN, respectively. Neither Timer/Counter 1 (TCNT1) nor Timer/Counter 2 (TCNT2) can be configured to operate as an external event counter or to operate in the pulse-accumulate mode because the TB input is used as a capture input. Attempting to select one of these configurations will cause one or both counters to stop. In this mode, Timer/Counter 2 must be enabled at all times.
Reload A TCRA
TAPND
Underflow TAIEN Timer 1 Clock Timer/Counter 1 TCNT1 TAEN
Timer Interrupt 1
TA
Timer Interrupt 1 TBIEN TBPND Capture B TCRB Preset TBEN Timer 2 Clock Timer/Counter 2 TnCNT2 TB
TDPND Timer Interrupt 2 TDIEN DS087
Figure 85.
Input Capture Plus Timer Mode
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24.3
TIMER INTERRUPTS
24.4
TIMER I/O FUNCTIONS
The Multi-Function Timer unit has four interrupt sources, designated A, B, C, and D. Interrupt sources A, B, and C are mapped into a single system interrupt called Timer Interrupt 1, while interrupt source D is mapped into a system interrupt called Timer Interrupt 2. Each of the four interrupt sources has its own enable bit and pending bit. The enable bits are named TAIEN, TBIEN, TCIEN, and TDIEN. The pending bits are named TAPND, TBPND, TCPND, and TDPND.
The Multi-Function Timer unit uses two I/O pins, called TA and TB. The function of each pin depends on the timer operating mode and the TAEN and TBEN enable bits. Table 68 shows the functions of the pins in each operating mode, and for each combination of enable bit settings.
When the TA pin is configured to operate as a PWM output (TAEN = 1), the state of the pin is toggled on each underflow of the TCNT1 counter. In this case, the initial value on the Timer Interrupts 1 and 2 are system interrupts TA and TB pin is determined by the TAOUT bit. For example, to start (IRQ14 and IRQ13), respectively. with TA high, software must set the TAOUT bit before enTable 67 shows the events that trigger interrupts A, B, C, abling the timer clock. This option is available only when the and D in each of the four operating modes. Note that some timer is configured to operate in Mode 1, 3, or 4 (in other words, when TCRA is not used in Capture mode). interrupt sources are not used in some operating modes. Table 67 Timer Interrupts Overview Interrupt Pending Bit TAPND TBPND TCPND Timer TDPND Int. 2 (TB Int.) Mode 1 PWM + Counter TCNT1 reload from TCRA TCNT1 reload from TCRB N/A TCNT2 underflow Mode 2 Dual Input Capture + Counter Input capture on TA transition Input Capture on TB transition TCNT1 underflow TCNT2 underflow Mode 3 Dual Counter TCNT1 reload from TCRA N/A N/A TCNT2 reload from TCRB Mode 4 Single Capture + Counter TCNT1 reload from TCRA Input Capture on TB transition N/A TCNT2 underflow
Sys. Int.
Timer Int. 1 (TA Int.)
Table 68 Timer I/O Functions Mode 1 I/O TAEN TBEN TAEN = 0 TBEN = X TAEN = 1 TBEN = X TB TAEN = X TBEN = 0 TAEN = X TBEN = 1 PWM + Counter No Output Mode 2 Dual Input Capture + counter Capture TCNT1 into TCRA Mode 3 Dual Counter No Output Toggle Toggle Output on Underflow of TCNT1 Ext. Event or Pulse Accumulate Input Ext. Event or Pulse Accumulate Input Mode 4 Single Capture + counter No Output Toggle Toggle Output on Underflow of TCNT1 Capture TCNT2 into TCRB Capture TCNT2 into TCRB and Preset TCNT2
TA
Toggle Output on Capture TCNT1 into Underflow of TCNT1 TCRA and Preset TCNT1 Ext. Event or Pulse Accumulate Input Ext. Event or Pulse Accumulate Input Capture TCNT1 into TCRB Capture TCNT1 into TCRB and Preset TCNT1
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24.5
TIMER REGISTERS
24.5.2
Clock Unit Control Register (TCKC)
Table 69 lists the CPU-accessible registers used to control the Multi-Function Timers. Table 69 Multi-Function Timer Registers Name TPRSC TCKC TCNT1 TCNT2 TCRA TCRB TCTRL TICTL TICLR 24.5.1 Address FF FF48h FF FF4Ah FF FF40h FF FF46h FF FF42h FF FF44h FF FF4Ch FF FF4Eh FF FF50h Description Clock Prescaler Register Clock Unit Control Register
The TCKC register is a byte-wide, read/write register that selects the clock source for each timer/counter. Selecting the clock source also starts the counter. This register is cleared on reset, which disables the timer/counters. The register format is shown below. 7 6 5 C2CSEL 3 2 C1CSEL 0
Reserved
C1CSEL Timer/Counter 1 Register Timer/Counter 2 Register Reload/Capture A Register Reload/Capture B Register Timer Mode Control Register Timer Interrupt Control Register Timer Interrupt Clear Register
C2CSEL
Clock Prescaler Register (TPRSC)
The TPRSC register is a byte-wide, read/write register that holds the current value of the 5-bit clock prescaler (CLKPS). This register is cleared on reset. The register format is shown below. 7 Reserved 5 4 CLKPS 0
The Counter 1 Clock Select field specifies the clock mode for Timer/Counter 1 as follows: 000 - No clock (Timer/Counter 1 stopped, modes 1, 2, and 3 only). 001 - Prescaled System Clock. 010 - External event on TB (modes 1 and 3 only). 011 - Pulse-accumulate mode based on TB (modes 1 and 3 only). 100 - Slow Clock.* 101 - Reserved. 110 - Reserved. 111 - Reserved. The Counter 2 Clock Select field specifies the clock mode for Timer/Counter 2 as follows: 000 - No clock (Timer/Counter 2 stopped, modes 1, 2, and 3 only). 001 - Prescaled System Clock. 010 - External event on TB (modes 1 and 3 only). 011 - Pulse-accumulate mode based on TB (modes 1 and 3 only). 100 - Slow Clock* 101 - Reserved. 110 - Reserved. 111 - Reserved.
* Operation of the Slow Clock is determined by the CRCTRL.SCLK control bit, as described in Section 11.9.1. 24.5.3 Timer/Counter 1 Register (TCNT1)
CLKPS
The Clock Prescaler field specifies the divisor used to generate the Timer Clock from the System Clock. When the timer is configured to use the prescaled clock, the System Clock is divided by (CLKPS + 1) to produce the timer clock. Therefore, the System Clock divisor can range from 1 to 32.
The TCNT1 register is a word-wide, read/write register that holds the current count value for Timer/Counter 1. The register contents are not affected by a reset and are unknown after power-up. 15 TCNT1 0
24.5.4
Timer/Counter 2 Register (TCNT2)
The TCNT2 register is a word-wide, read/write register that holds the current count value for Timer/Counter 2. The register contents are not affected by a reset and are unknown after power-up. 15 TCNT2 0
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24.5.5
Reload/Capture A Register (TCRA)
TAEN
The TCRA register is a word-wide, read/write register that holds the reload or capture value for Timer/Counter 1. The register contents are not affected by a reset and are unknown after power-up. 15 TCRA 0
24.5.6
Reload/Capture B Register (TCRB)
TBEN
The TCRB register is a word-wide, read/write register that holds the reload or capture value for Timer/Counter 2. The register contents are not affected by a reset and are unknown after power-up. 15 TCRB TAOUT 0
24.5.7
Timer Mode Control Register (TCTRL)
The TCTRL register is a byte-wide, read/write register that sets the operating mode of the timer/counter and the TA and TB pins. This register is cleared at reset. The register format is shown below. 7 6 5 4 3 2 1 0
TEN TAOUT TBEN TAEN TBEDG TAEDG MDSEL TEN
MDSEL
TAEDG
TBEDG
The Mode Select field sets the operating mode of the timer/counter as follows: 00 - Mode 1: PWM plus system timer. 01 - Mode 2: Dual-Input Capture plus system timer. 10 - Mode 3: Dual Timer/Counter. 11 - Mode 4: Single-Input Capture and Single Timer. The TA Edge Polarity bit selects the polarity of the edges that trigger the TA input. 0 - TA input is sensitive to falling edges (high to low transitions). 1 - TA input is sensitive to rising edges (low to high transitions). The TB Edge Polarity bit selects the polarity of the edges that trigger the TB input. In pulseaccumulate mode, when this bit is set, the counter is enabled only when TB is high; when this bit is clear, the counter is enabled only when TB is low. 0 - TB input is sensitive to falling edges (high to low transitions). 1 - TB input is sensitive to rising edges (low to high transitions).
The TA Enable bit controls whether the TA pin is enabled to operate as a preset input or as a PWM output, depending on the timer operating mode. In Mode 2 (Dual Input Capture), a transition on the TA pin presets the TCNT1 counter to FFFFh. In the other modes, TA functions as a PWM output. When this bit is clear, operation of the pin for the timer/counter is disabled. 0 - TA input disabled. 1 - TA input enabled. The TB Enable bit controls whether the TB pin in enabled to operate in Mode 2 (Dual Input Capture) or Mode 4 (Single Input Capture and Single Timer). A transition on the TB pin presets the corresponding timer/counter to FFFFh (TCNT1 in Mode 2 or TCNT2 in Mode 4). When this bit is clear, operation of the pin for the timer/counter is disabled. This bit setting has no effect in Mode 1 or Mode 3. 0 - TB input disabled. 1 - TB input enabled. The TA Output Data bit indicates the current state of the TA pin when the pin is used as a PWM output. The hardware sets and clears this bit, but software can also read or write this bit at any time and therefore control the state of the output pin. In case of conflict, a software write has precedence over a hardware update. This bit setting has no effect when the TA pin is used as an input. 0 - TA pin is low. 1 - TA pin is high. The Timer Enable bit controls whether the Multi-Function Timer is enabled. When the module is disabled all clocks to the counter unit are stopped to minimize power consumption. For that reason, the timer/counter registers (TCNT1 and TCNT2), the capture/reload registers (TCRA and TCRB), and the interrupt pending bits (TXPND) cannot be written in this mode. Also, the 5-bit clock prescaler and the interrupt pending bits are cleared, and the TA I/O pin becomes an input. 0 - Multi-Function Timer is disabled. 1 - Multi-Function Timer is enabled.
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24.5.8
Timer Interrupt Control Register (TICTL)
TBIEN
The TICTL register is a byte-wide, read/write register that contains the interrupt enable bits and interrupt pending bits for the four timer interrupt sources, designated A, B, C, and D. The condition that causes each type of interrupt depends on the operating mode, as shown in Table 67. This register is cleared upon reset. The register format is shown below. 7 6 5 4 3 2 1 0 TCIEN
TDIEN TCIEN TBIEN TAIEN TDPND TCPND TBPND TAPND TDIEN
TAPND
TBPND
TCPND
TDPND
TAIEN
The Timer Interrupt Source A Pending bit indicates that timer interrupt condition A has occurred. For an explanation of interrupt conditions A, B, C, and D, see Table 67. This bit can be set by hardware or by software. To clear this bit, software must use the Timer Interrupt Clear Register (TICLR). Attempting to directly write a 0 to this bit is ignored. 0 - Interrupt source A has not triggered. 1 - Interrupt source A has triggered. The Timer Interrupt Source B Pending bit indicates that timer interrupt condition B has occurred. For an explanation of interrupt conditions A, B, C, and D, see Table 67. This bit can be set by hardware or by software. To clear this bit, software must use the Timer Interrupt Clear Register (TICLR). Attempting to directly write a 0 to this bit is ignored. 0 - Interrupt source B has not triggered. 1 - Interrupt source B has triggered. The Timer Interrupt Source C Pending bit indicates that timer interrupt condition C has occurred. For an explanation of interrupt conditions A, B, C, and D, see Table 67. This bit can be set by hardware or by software. To clear this bit, software must use the Timer Interrupt Clear Register (TICLR). Attempting to directly write a 0 to this bit is ignored. 0 - Interrupt source C has not triggered. 1 - Interrupt source C has triggered. The Timer Interrupt Source D Pending bit indicates that timer interrupt condition D has occurred. For an explanation of interrupt conditions A, B, C, and D, see Table 67. This bit can be set by hardware or by software. To clear this bit, software must use the Timer Interrupt Clear Register (TICLR). Attempting to directly write a 0 to this bit is ignored. 0 - Interrupt source D has not triggered. 1 - Interrupt source D has triggered. The Timer Interrupt A Enable bit controls whether an interrupt is generated on each occurrence of interrupt condition A. For an explanation of interrupt conditions A, B, C, and D, see Table 67. 0 - Condition A interrupts disabled. 1 - Condition A interrupts enabled.
The Timer Interrupt B Enable bit controls whether an interrupt is generated on each occurrence of interrupt condition B. For an explanation of interrupt conditions A, B, C, and D, see Table 67. 0 - Condition B interrupts disabled. 1 - Condition B interrupts enabled. The Timer Interrupt C Enable bit controls whether an interrupt is generated on each occurrence of interrupt condition C. For an explanation of interrupt conditions A, B, C, and D, see Table 67. 0 - Condition C interrupts disabled. 1 - Condition C interrupts enabled. The Timer Interrupt D Enable bit controls whether an interrupt is generated on each occurrence of interrupt condition D. For an explanation of interrupt conditions A, B, C, and D, see Table 67. 0 - Condition D interrupts disabled. 1 - Condition D interrupts enabled. Timer Interrupt Clear Register (TICLR)
24.5.9
The TICLR register is a byte-wide, write-only register that allows software to clear the TAPND, TBPND, TCPND, and TDPND bits in the Timer Interrupt Control (TICTRL) register. Do not modify this register with instructions that access the register as a read-modify-write operand, such as the bit manipulation instructions. The register reads as FFh. The register format is shown below. 7 Reserved 4 3 2 1 0
TDCLR TCCLR TBCLR TACLR
TACLR
TBCLR
TCCLR
TDCLR
The Timer Pending A Clear bit is used to clear the Timer Interrupt Source A Pending bit (TAPND) in the Timer Interrupt Control register (TICTL). 0 - Writing a 0 has no effect. 1 - Writing a 1 clears the TAPND bit. The Timer Pending A Clear bit is used to clear the Timer Interrupt Source B Pending bit (TBPND) in the Timer Interrupt Control register (TICTL). 0 - Writing a 0 has no effect. 1 - Writing a 1 clears the TBPND bit. The Timer Pending C Clear bit is used to clear the Timer Interrupt Source C Pending bit (TCPND) in the Timer Interrupt Control register (TICTL). 0 - Writing a 0 has no effect. 1 - Writing a 1 clears the TCPND bit. The Timer Pending D Clear bit is used to clear the Timer Interrupt Source D Pending bit (TDPND) in the Timer Interrupt Control register (TICTL). 0 - Writing a 0 has no effect. 1 - Writing a 1 clears the TDPND bit.
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25.0 Versatile Timer Unit (VTU)
The Versatile Timer Unit (VTU) contains four fully independent 16-bit timer subsystems. Each timer subsystem can operate either as dual 8-bit PWM timers, as a single 16-bit PWM timer, or as a 16-bit counter with 2 input capture channels. These timer subsystems offers an 8-bit clock prescaler to accommodate a wide range of system frequencies. The VTU offers the following features: The VTU can be configured to provide: -- Eight fully independent 8-bit PWM channels -- Four fully independent 16-bit PWM channels -- Eight 16-bit input capture channels The VTU consists of four timer subsystems, each of which contains: -- A 16-bit counter -- Two 16-bit capture / compare registers -- An 8-bit fully programmable clock prescaler Each of the four timer subsystems can operate in the following modes: -- Low power mode, i.e. all clocks are stopped -- Dual 8-bit PWM mode -- 16-bit PWM mode -- Dual 16-bit input capture mode The VTU controls a total of eight I/O pins, each of which can function as either: -- PWM output with programmable output polarity -- Capture input with programmable event detection and timer reset A flexible interrupt scheme with -- Four separate system level interrupt requests -- A total of 16 interrupt sources each with a separate interrupt pending bit and interrupt enable bit
25.1
VTU FUNCTIONAL DESCRIPTION
The VTU is comprised of four timer subsystems. Each timer subsystem contains an 8-bit clock prescaler, a 16-bit upcounter, and two 16-bit registers. Each timer subsystem controls two I/O pins which either function as PWM outputs or capture inputs depending on the mode of operation. There are four system-level interrupt requests, one for each timer subsystem. Each system-level interrupt request is controlled by four interrupt pending bits with associated enable/disable bits. All four timer subsystems are fully independent, and each may operate as a dual 8-bit PWM timer, a 16-bit PWM timer, or as a dual 16-bit capture timer. Figure 86 shows the main elements of the VTU.
15 MODE
0
15 INTCTL 15 INTPND
0
15 IO1CTL
0
0
15 IO2CTL
0
Timer Subsystem 1 7 C1 PRSC == Prescaler Counter 15 Count1 Compare - Capture PERCAP1 Compare - Capture DTYCAP1 0 15 7
Timer Subsystem 2 7 C2 PRSC == Prescaler Counter 0 Count2 Compare - Capture PERCAP2 Compare - Capture DTYCAP2 15
Timer Subsystem 3 7 C3 PRSC == Prescaler Counter 0 Count3 Compare - Capture PERCAP3 Compare - Capture DTYCAP3 15
Timer Subsystem 4 C4RSC == Prescaler Counter 0 Count4 Compare - Capture PERCAP4 Compare - Capture DTYCAP4
I/O Control
I/O Control
I/O Control
I/O Control
I/O Control
I/O Control
I/O Control
I/O Control
TIO1
TIO2
TIO3
TIO4
TIO5
TIO6
TIO7
TIO8 DS088
Figure 86. Versatile Timer Unit Block Diagram
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25.1.1
The period of the PWM output waveform is determined by Each timer subsystem may be configured to generate two the value of the PERCAPx register. The TIOx output starts fully independent PWM waveforms on the respective TIOx at the default value as programmed in the IOxCTL.PxPOL pins. In this mode, the counter COUNTx is split and oper- bit. Once the counter value reaches the value of the period ates as two independent 8-bit counters. Each counter incre- register PERCAPx, the counter is cleared on the next counter increment. On the following increment from 00h to ments at the rate determined by the clock prescaler. 01h, the TIOx output will change to the opposite of the deEach of the two 8-bit counters may be started and stopped fault value. separately using the corresponding TxRUN bits. Once either of the two 8-bit timers is running, the clock prescaler The duty cycle of the PWM output waveform is controlled by starts counting. Once the clock prescaler counter value the DTYCAPx register value. Once the counter value reachmatches the value of the associated CxPRSC register field, es the value of the duty cycle register DTYCAPx, the PWM output TIOx changes back to its default value on the next COUNTx is incremented. counter increment. Figure 87 illustrates this concept.
COUNTx PERCAPx 09 08 07 06 05 DTYCAPx 03 02 01 00 TxRUN = 1 00 01 02 04 03 04 05 06 07 08 0A 09 0A
Dual 8-bit PWM Mode
TIOx (PxPOL = 0)
TIOx (PxPOL = 1)
DS089
Figure 87. The period time is determined by the following formula:
VTU PWM Generation Reading the PERCAPx or DTYCAPx register will always return the most recent value written to it. The counter registers can be written if both 8-bit counters are stopped. This allows software to preset the counters before starting, which can be used to generate PWM output waveforms with a phase shift relative to each other. If the counter is written with a value other than 00h, it will start incrementing from that value. The TIOx output will remain at its default value until the first 00h to 01h transition of the counter value occurs. If the counter is preset to values which are less than or equal to the value held in the period register (PERCAPx) the counter will count up until a match between the counter value and the PERCAPx register value occurs. The counter will then be cleared and continue counting up. Alternatively, the counter may be written with a value which is greater than the value held in the period register. In that case the counter will count up to FFh, then roll over to 00h. In any case, the TIOx pin always changes its state at the 00h to 01h transition of the counter.
PWM Period = (PERCAPx + 1) x (CxPRSC + 1) x TCLK The duty cycle in percent is calculated as follows: Duty Cycle = (DTYCAPx / (PERCAPx + 1)) x 100 If the duty cycle register (DTYCAPx) holds a value which is greater than the value held in the period register (PERCAPx) the TIOx output will remain at the opposite of its default value which corresponds to a duty cycle of 100%. If the duty cycle register (DTYCAPx) register holds a value of 00h, the TIOx output will remain at the default value which corresponds to a duty cycle of 0%, in which case the value in the PERCAPx register is irrelevant. This scheme allows the duty cycle to be programmed in a range from 0% to 100%.
In order to allow fully synchronized updates of the period and duty cycle compare values, the PERCAPx and DTYCAPx registers are double buffered when operating in PWM mode. Therefore, if software writes to either the period or duty cycle register while either of the two PWM channels is enabled, the new value will not take effect until the counter Software may only write to the COUNTx register if both value matches the previous period value or the timer is TxRUN bits of a timer subsystem are clear. Any writes to the counter register while either timer is running will be ignored. stopped.
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The two I/O pins associated with a timer subsystem function as independent PWM outputs in the dual 8-bit PWM mode. If a PWM timer is stopped using its associated MODE.TxRUN bit the following actions result: The associated TIOx pin will return to its default value as defined by the IOxCTL.PxPOL bit. The counter will stop and will retain its last value. Any pending updates of the PERCAPx and DTYCAPx register will be completed. The prescaler counter will be stopped and reset if both MODE.TxRUN bits are cleared. Figure 88 illustrates the configuration of a timer subsystem while operating in dual 8-bit PWM mode. The numbering in Figure 88 refers to timer subsystem 1 but equally applies to the other three timer subsystems.
7 C1PRSC == Prescaler Counter 0 TMOD1 = 01
Figure 89 illustrates the configuration of a timer subsystem while operating in 16-bit PWM mode. The numbering in Figure 89 refers to timer subsystem 1 but equally applies to the other three timer subsystems.
7 C1PRSC == Prescaler Counter 0 TMOD1 = 10
T1RUN
15 Restart Count1[15:0] Compare PERCAP1[15:0] Compare DTYCAP1[15:0]
0 [15:0]
T2RUN
T1RUN R S Q R S Q
15 Res COUNT1[15:8] Compare PERCAP1[15:8] Compare DTYCAP1[15:8]
0 [15:8]
7 Res COUNT1[7:0] Compare
0 [7:0] P2POL TIO2 P1POL TIO1 DS091 PERCAP1[7:0]
Figure 89. VTU 16-bit PWM Mode
Compare DTYCAP1[7:0]
25.1.3
Dual 16-Bit Capture Mode
R S
Q
R S
Q
In addition to the two PWM modes, each timer subsystem may be configured to operate in an input capture mode which provides two 16-bit capture channels. The input capture mode can be used to precisely measure the period and duty cycle of external signals.
TIO1 DS090
P2POL TIO2
P1POL
Figure 88. VTU Dual 8-Bit PWM Mode 25.1.2 16-Bit PWM Mode
In capture mode the counter COUNTx operates as a 16-bit up-counter while the two TIOx pins associated with a timer subsystem operate as capture inputs. A capture event on the TIOx pins causes the contents of the counter register (COUNTx) to be copied to the PERCAPx or DTYCAPx registers respectively. Starting the counter is identical to the 16-bit PWM mode, i.e. setting the lower of the two MODE.TxRUN bits will start the counter and the clock prescaler. In addition, the capture event inputs are enabled once the MODE.TxRUN bit is set. The TIOx capture inputs can be independently configured to detect a capture event on either a positive transition, a negative transition or both a positive and a negative transition. In addition, any capture event may be used to reset the counter COUNTx and the clock prescaler counter. This avoids the need for software to keep track of timer overflow conditions and greatly simplifies the direct frequency and duty cycle measurement of an external signal.
Each of the four timer subsystems may be independently configured to provide a single 16-bit PWM channel. In this case the lower and upper bytes of the counter are concatenated to form a single 16-bit counter. Operation in 16-bit PWM mode is conceptually identical to the dual 8-bit PWM operation as outlined under Dual 8-bit PWM Mode on page 180. The 16-bit timer may be started or stopped with the lower MODE.TxRUN bit, i.e. T1RUN for timer subsystem 1. The two TIOx outputs associated with a timer subsystem can be used to produce either two identical PWM waveforms or two PWM waveforms of opposite polarities. This can be accomplished by setting the two PxPOL bits of the respective timer subsystem to either identical or opposite values.
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Figure 90 illustrates the configuration of a timer subsystem while operating in capture mode. The numbering in Figure 90 refers to timer subsystem 1 but equally applies to the other three timer subsystems.
7 C1PRSC == Prescaler Counter 0 TMOD1=11
terrupt pending bits are denoted IxAPD through IxDPD where "x" relates to the specific timer subsystem. There is one system level interrupt request for each of the four timer subsystems. Figure 91 illustrates the interrupt structure of the versatile timer module.
I1AEN I1BEN I1CEN
T1RUN
I1DEN 0 15:0
15 Restart Count1[15:0] Compare PERCAP1[15:0] Compare DTYCAP1[15:0]
I1APD I1BPD I1CPD I1DPD
System Interrupt Request 1
I4AEN I4BEN cap rst 2 C1EDG TIO1 0 cap rst 2 C2EDG TIO2 DS092 0 I4APD I4BPD I4CPD I4DPD DS093 System Interrupt Request 4 I4CEN I4DEN
Figure 90. 25.1.4
VTU Dual 16-bit Capture Mode
Low Power Mode
In case a timer subsystem is not used, software can place it in a low-power mode. All clocks to a timer subsystem are stopped and the counter and prescaler contents are frozen once low-power mode is entered. Software may continue to write to the MODE, INTCTL, IOxCTL, and CLKxPS registers. Write operations to the INTPND register are allowed; but if a timer subsystem is in low-power mode, its associated interrupt pending bits cannot be cleared. Software cannot write to the COUNTx, PERCAPx, and DTYCAPx registers of a timer subsystem while it is in low-power mode. All registers can be read at any time. 25.1.5 Interrupts
Figure 91. VTU Interrupt Request Structure Each of the timer pending bits - IxAPD through IxDPD - is set by a specific hardware event depending on the mode of operation, i.e., PWM or Capture mode. Table 70 outlines the specific hardware events relative to the operation mode which cause an interrupt pending bit to be set. 25.1.6 ISE Mode operation
The VTU has a total of 16 interrupt sources, four for each of the four timer subsystems. All interrupt sources have a pending bit and an enable bit associated with them. All in-
The VTU supports breakpoint operation of the In-SystemEmulator (ISE). If FREEZE is asserted, all timer counter clocks will be inhibited and the current value of the timer registers will be frozen; in capture mode, all further capture events are disabled. Once FREEZE becomes inactive, counting will resume from the previous value and the capture input events are re-enabled.
Table 70 VTU Interrupt Sources Pending Flag IxAPD IxBPD IxCPD IxDPD Dual 8-bit PWM Mode Low Byte Duty Cycle match Low Byte Period match High Byte Duty Cycle match High Byte Period match 16-bit PWM Mode Duty Cycle match Period match N/A N/A Capture Mode Capture to PERCAPx Capture to DTYCAPx Counter Overflow N/A
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25.2
VTU REGISTERS
25.2.1
Mode Control Register (MODE)
The VTU contains a total of 19 user accessible registers, as The MODE register is a word-wide read/write register which listed in Table 71. All registers are word-wide and are initial- controls the mode selection of all four timer subsystems. ized to a known value upon reset. All software accesses to The register is clear after reset. the VTU registers must be word accesses. Table 71 VTU Registers Name MODE IO1CTL IO2CTL INTCTL INTPND CLK1PS CLK2PS COUNT1 PERCAP1 DTYCAP1 COUNT2 PERCAP2 DTYCAP2 COUNT3 PERCAP3 DTYCAP3 COUNT4 PERCAP4 DTYCAP4 Address FF FF80h FF FF82h FF FF84h FF FF86h FF FF88h FF FF8Ah FF FF98h FF FF8Ch FF FF8Eh FF FF90h FF FF92h FF FF94h FF FF96h FF FF9Ah FF FF9Ch FF FF9Eh FF FFA0h FF FFA2h FF FFA4h Description Mode Control Register I/O Control Register 1 I/O Control Register 2 Interrupt Control Register Interrupt Pending Register Clock Prescaler Register 1 Clock Prescaler Register 2 Counter 1 Register Period/Capture 1 Register Duty Cycle/Capture 1 Register Counter 2 Register Period/Capture 2 Register Duty Cycle/Capture 2 Register Counter 3 Register Period/Capture 3 Register Duty Cycle/Capture 3 Register Counter 4 Register Period/Capture 4 Register Duty Cycle/Capture 4 Register TMODx TxRUN The Timer Run bit controls whether the corresponding timer is stopped or running. If set, the associated counter and clock prescaler is started depending on the mode of operation. Once set, the clock to the clock prescaler and the counter are enabled and the counter will increment each time the clock prescaler counter value matches the value defined in the associated clock prescaler field (CxPRSC). 0 - Timer stopped. 1 - Timer running. The Timer System Operating Mode field enables or disables the Timer Subsystem and defines its operating mode. 00 - Low-Power Mode. All clocks to the counter subsystem are stopped. The counter is stopped regardless of the value of the TxRUN bits. Read operations to the Timer Subsystem will return the last value; software must not perform any write operations to the Timer Subsystem while it is disabled since those will be ignored. 01 - Dual 8-bit PWM mode. Each 8-bit counter may individually be started or stopped via its associated TxRUN bit. The TIOx pins will function as PWM outputs. 10 - 16-bit PWM mode. The two 8-bit counters are concatenated to form a single 16-bit counter. The counter may be started or stopped with the lower of the two TxRUN bits, i.e. T1RUN, T3RUN, T5RUN, and T7RUN. The TIOx pins will function as PWM outputs. 11 - Capture Mode. Both 8-bit counters are concatenated and operate as a single 16-bit counter. The counter may be started or stopped with the lower of the two TxRUN bits, i.e., T1RUN, T3RUN, T5RUN, and T7RUN. The TIOx pins will function as capture inputs. 7 6 5 4 3 2 1 0 TMOD2 T4RUN T3RUN TMOD1 T2RUN T1RUN
15
14
13
12
11
10
9
8
TMOD4 T8RUN T7RUN TMOD3 T6RUN T5RUN
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25.2.2
I/O Control Register 1 (IO1CTL)
25.2.3
I/O Control Register 2 (IO2CTL)
The I/O Control Register 1 (IO1CTL) is a word-wide read/ write register. The register controls the function of the I/O pins TIO1 through TIO4 depending on the selected mode of operation. The register is clear after reset. 7 P2POL 6 C2EDG 4 3 P1POL 2 C1EDG 0
The IO2CTL register is a word-wide read/write register. The register controls the functionality of the I/O pins TIO5 through TIO8 depending on the selected mode of operation. The register is cleared at reset. 7 P6POL 6 C6EDG 4 3 P5POL 2 C5EDG 0
15 P4POL
14 C4EDG
12
11 P3POL
10 C3EDG
8
15 P8POL
14 C8EDG
12
11 P7POL
10 C7EDG
8
CxEDG
The Capture Edge Control field specifies the The functionality of the bit fields of the IO2CTL register is polarity of a capture event and the reset of the identical to the ones described in the IO1CTL register seccounter. The value of this three bit field has no tion. effect while operating in PWM mode. 25.2.4 Interrupt Control Register (INTCTL) CxEDG Capture Counter Reset The INTCTL register is a word-wide read/write register. It 000 001 010 011 100 101 110 111 Rising edge Falling edge Rising edge Falling edge Both edges Both edges Both edges Both edges No No Yes Yes No Rising edge Falling edge Both edges 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 I2DEN I2CEN I2BEN I2AEN I1DEN I1CEN I1BEN I1AEN contains the interrupt enable bits for all 16 interrupt sources of the VTU. Each interrupt enable bit corresponds to an interrupt pending bit located in the Interrupt Pending Register (INTPND). All INTCTL register bits are solely under software control. The register is clear after reset.
I4DEN I4CEN I4BEN I4AEN I3DEN I3CEN I3BEN I3AEN
PxPOL
The PWM Polarity bit selects the output polarity. While operating in PWM mode the bit specifies the polarity of the corresponding IxAEN PWM output (TIOx). Once a counter is stopped, the output will assume the value of PxPOL, i.e., its initial value. The PxPOL bit has no effect while operating in capture mode. 0 - The PWM output goes high at the 00h to 01h transition of the counter and will go low once the counter value matches the duty cycle value. 1 - The PWM output goes low at the 00h to IxBEN 01h transition of the counter and will go high once the counter value matches the duty cycle value.
The Timer x Interrupt A Enable bit controls interrupt requests triggered on the corresponding IxAPD bit being set. The associated IxAPD bit will be updated regardless of the value of the IxAEN bit. 0 - Disable system interrupt request for the IxAPD pending bit. 1 - Enable system interrupt request for the IxAPD pending bit. The Timer x Interrupt B Enable bit controls interrupt requests triggered on the corresponding IxBPD bit being set. The associated IxBPD bit will be updated regardless of the value of the IxBEN bit. 0 - Disable system interrupt request for the IxBPD pending bit. 1 - Enable system interrupt request for the IxBPD pending bit.
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IxCEN
IxDEN
The Timer x Interrupt C Enable bit controls interrupt requests triggered on the corresponding IxCPD bit being set. The associated IxCPD bit will be updated regardless of the value of the IxCEN bit. 0 - Disable system interrupt request for the IxCPD pending bit. 1 - Enable system interrupt request for the IxCPD pending bit. Timer x Interrupt D Enable bit controls interrupt requests triggered on the corresponding IxDPD bit being set. The associated IxDPD bit will be updated regardless of the value of the IxDEN bit. 0 - Disable system interrupt request for the IxDPD pending bit. 1 - Enable system interrupt request for the IxDPD pending bit. Interrupt Pending Register (INTPND)
IxDPD
The Timer x Interrupt D Pending bit indicates that an interrupt condition for the related timer subsystem has occurred. Table 70 on page 182 lists the hardware condition which causes this bit to be set. 0 - No interrupt pending. 1 - Timer interrupt condition occurred. Clock Prescaler Register 1 (CLK1PS)
25.2.6
The CLK1PS register is a word-wide read/write register. The register is split into two 8-bit fields called C1PRSC and C2PRSC. Each field holds the 8-bit clock prescaler compare value for timer subsystems 1 and 2 respectively. The register is cleared at reset. 15 C2PRSC 8 7 C1PRSC 0
25.2.5
The INTPND register is a word-wide read/write register which contains all 16 interrupt pending bits. There are four interrupt pending bits called IxAPD through IxDPD for each timer subsystem. Each interrupt pending bit is set by a hardware event and can be cleared if software writes a 1 to the bit position. The value will remain unchanged if a 0 is written to the bit position. All interrupt pending bits are cleared (0) upon reset. 7 6 5 4 3 2 1 0
C1PRSC
C2PRSC
I2DPD I2CPD I2BPD I2APD I1DPD I1CPD I1BPD I1APD
15
14
13
12
11
10
9
8 25.2.7
The Clock Prescaler 1 Compare Value field holds the 8-bit prescaler value for timer subsystem 1. The counter of timer subsystem is incremented each time when the clock prescaler compare value matches the value of the clock prescaler counter. The division ratio is equal to (C1PRSC + 1). For example, 00h is a ratio of 1, and FFh is a ratio of 256. The Clock Prescaler 2 Compare Value field holds the 8-bit prescaler value for timer subsystem 2. The counter of timer subsystem is incremented each time when the clock prescaler compare value matches the value of the clock prescaler counter. The division ratio is equal to (C2PRSC + 1). Clock Prescaler Register 2 (CLK2PS)
I4DPD I4CPD I4BPD I4APD I3DPD I3CPD I3BPD I3APD
IxAPD
IxBPD
IxCPD
The Timer x Interrupt A Pending bit indicates that an interrupt condition for the related timer subsystem has occurred. Table 70 on page 182 lists the hardware condition which causes this bit to be set. 0 - No interrupt pending. 1 - Timer interrupt condition occurred. The Timer x Interrupt B Pending bit indicates that an interrupt condition for the related timer subsystem has occurred. Table 70 on page 182 lists the hardware condition which causes this bit to be set. 0 - No interrupt pending. 1 - Timer interrupt condition occurred. The Timer x Interrupt C Pending bit indicates that an interrupt condition for the related timer subsystem has occurred. Table 70 on page 182 lists the hardware condition which causes this bit to be set. 0 - No interrupt pending. 1 - Timer interrupt condition occurred.
The Clock Prescaler Register 2 (CLK2PS) is a word-wide read/write register. The register is split into two 8-bit fields called C3PRSC and C4PRSC. Each field holds the 8-bit clock prescaler compare value for timer subsystems 3 and 4 respectively. The register is cleared at reset. 15 C4PRSC 8 7 C3PRSC 0
C3PRSC
C4PRSC
The Clock Prescaler 3 Compare Value field holds the 8-bit prescaler value for timer subsystem 3. The counter of timer subsystem is incremented each time when the clock prescaler compare value matches the value of the clock prescaler counter. The division ratio is equal to (C3PRSC + 1). The Clock Prescaler 4 Compare Value field holds the 8-bit prescaler value for timer subsystem 4. The counter of timer subsystem is incremented each time when the clock prescaler compare value matches the value of the clock prescaler counter. The division ratio is equal to (C4PRSC + 1).
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25.2.8
Counter Register n (COUNTx)
25.2.10 Duty Cycle/Capture Register n (DTYCAPx) The Duty Cycle/Capture (DTYCAPx) registers are wordwide read/write registers. There are a total of four registers called DTYCAP1 through DTYCAP4, one for each timer subsystem. The registers hold the period compare value in PWM mode or the counter value at the time the last associated capture event occurred. In PWM mode, the register is double buffered. If a new duty cycle compare value is written while the counter is running, the write will not take effect until the counter value matches the previous period compare value or until the counter is stopped. The update takes effect on period boundaries only. Reading may take place at any time and will return the most recent value which was written. The DTYCAPx registers are cleared at reset. 15 DCAPx 0
The Counter (COUNTx) registers are word-wide read/write registers. There are a total of four registers called COUNT1 through COUNT4, one for each of the four timer subsystems. Software may read the registers at any time. Reading the register will return the current value of the counter. The register may only be written if the counter is stopped (i.e. if both TxRUN bits associated with a timer subsystem are clear). The registers are cleared at reset. 15 CNTx 0
25.2.9
Period/Capture Register n (PERCAPx)
The PERCAPx registers are word-wide read/write registers. There are a total of four registers called PERCAP1 through PERCAP4, one for each timer subsystem. The registers hold the period compare value in PWM mode of the counter value at the time the last associated capture event occurred. In PWM mode the register is double buffered. If a new period compare value is written while the counter is running, the write will not take effect until counter value matches the previous period compare value or until the counter is stopped. Reading may take place at any time and will return the most recent value which was written. The PERCAPx registers are cleared at reset. 15 PCAPx 0
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26.0 Register Map
Table 72 is a detailed memory map showing the specific memory address of the memory, I/O ports, and registers. The table shows the starting address, the size, and a brief description of each memory block and register. For detailed information on using these memory locations, see the applicable sections in the data sheet. All addresses not listed in the table are reserved and must not be read or written. An attempt to access an unlisted address will have unpredictable results. the byte-wide and word-wide registers reside at word boundaries (even addresses). Therefore, each byte-wide register uses only the lowest eight bits of the internal data bus. Most device registers are read/write registers. However, some registers are read-only or write-only, as indicated in the table. An attempt to read a write-only register or to write a read-only register will have unpredictable results.
When software writes to a register in which one or more bits Each byte-wide register occupies a single address and can are reserved, it must write a zero to each reserved bit unless be accessed only in a byte-wide transaction. Each word- indicated otherwise in the description of the register. Readwide register occupies two consecutive memory addresses ing a reserved bit returns an undefined value. and can be accessed only in a word-wide transaction. Both Table 72 Detailed Device Mapping Register Name Size Address Access Type Value After Reset Comments
CAN0 Module Message Buffers CMB0_CNSTAT CMB0_TSTP CMB0_DATA3 CMB0_DATA2 CMB0_DATA1 CMB0_DATA0 CMB0_ID0 CMB0_ID1 CMB1 CMB2 CMB3 CMB4 CMB5 CMB6 CMB7 CMB8 CMB9 Word Word Word Word Word Word Word Word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 0E F000h 0E F002h 0E F004h 0E F006h 0E F008h 0E F00Ah 0E F00Ch 0E F00Eh 0E F010h- 0E F01Fh 0E F020h- 0E F02Fh 0E F030h- 0E F03Fh 0E F040h- 0E F04Fh 0E F050h- 0E F05Fh 0E F060h- 0E F06Fh 0E F070h- 0E F07Fh 0E F080h- 0E F08Fh 0E F090h- 0E F09Fh Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0.
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Register Name
Size
Address 0E F0A0h- 0E F0AFh 0E F0B0h- 0E F0BFh 0E F0C0h- 0E F0CFh 0E F0D0h- 0E F0DFh 0E F0E0h- 0E F0EFh CAN0 Registers
Access Type Read/Write Read/Write Read/Write Read/Write Read/Write
Value After Reset XXXXh XXXXh XXXXh XXXXh XXXXh
Comments Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0.
CMB10 CMB11 CMB12 CMB13 CMB14
8-word 8-word 8-word 8-word 8-word
CGCR0 CTIM0 GMSKX0 GMSKB0 BMSKX0 BMSKB0 CIEN0 CIPND0 CICLR0 CICEN0 CSTPND0 CANEC0 CEDIAG0 CTMR0
Word Word Word Word Word Word Word Word Word Word Word Word Word Word
0E F100h 0E F102h 0E F104h 0E F106h 0E F108h 0E F10Ah 0E F10Ch 0E F10Eh 0E F110h 0E F112h 0E F114h 0E F116h 0E F118h 0E F11Ah
Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Write Only Read/Write Read Only Read Only Read Only Read Only
0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h
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CP3CN23
Register Name
Size
Address
Access Type
Value After Reset
Comments
CAN1 Module Message Buffers CMB0_CNSTAT CMB0_TSTP CMB0_DATA3 CMB0_DATA2 CMB0_DATA1 CMB0_DATA0 CMB0_ID0 CMB0_ID1 CMB1 CMB2 CMB3 CMB4 CMB5 CMB6 CMB7 CMB8 CMB9 CMB10 CMB11 CMB12 CMB13 CMB14 Word Word Word Word Word Word Word Word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 8-word 0E F200h 0E F202h 0E F204h 0E F206h 0E F208h 0E F20Ah 0E F20Ch 0E F20Eh 0E F210h- 0E F21Fh 0E F220h- 0E F22Fh 0E F230h- 0E F23Fh 0E F240h- 0E F24Fh 0E F250h- 0E F25Fh 0E F260h- 0E F26Fh 0E F270h- 0E F27Fh 0E F280h- 0E F28Fh 0E F290h- 0E F29Fh 0E F2A0h- 0E F2AFh 0E F2B0h- 0E F2BFh 0E F2C0h- 0E F2CFh 0E F2D0h- 0E F2DFh 0E F2E0h- 0E F2EFh Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh XXXXh Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0. Same register layout as CMB0.
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Register Name
Size
Address
Access Type
Value After Reset
Comments
CAN1 Registers CGCR1 CTIM1 GMSKX1 GMSKB1 BMSKX1 BMSKB1 CIEN1 CIPND1 CICLR1 CICEN1 CSTPND1 CANEC1 CEDIAG1 CTMR1 Word Word Word Word Word Word Word Word Word Word Word Word Word Word 0E F300h 0E F302h 0E F304h 0E F306h 0E F308h 0E F30Ah 0E F30Ch 0E F30Eh 0E F310h 0E F312h 0E F314h 0E F316h 0E F318h 0E F31Ah DMA Controller Double Word Double Word Double Word Double Word Word Word Word Byte Double Word Double Word Double Word Double Word Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Write Only Read/Write Read Only Read Only Read Only Read Only 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h
ADCA0 ADRA0 ADCB0 ADRB0 BLTC0 BLTR0 DMACNTL0 DMASTAT0 ADCA1 ADRA1 ADCB1 ADRB1
FF F800h FF F804h FF F808h FF F80Ch FF F810h FF F814h FF F81Ch FF F81Eh FF F820h FF F824h FF F828h FF F82Ch
Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write
0000 0000h 0000 0000h 0000 0000h 0000 0000h 0000h 0000h 0000h 00h 0000 0000h 0000 0000h 0000 0000h 0000 0000h
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Register Name BLTC1 BLTR1 DMACNTL1 DMASTAT1 ADCA2 ADRA2 ADCB2 ADRB2 BLTC2 BLTR2 DMACNTL2 DMASTAT2 ADCA3 ADRA3 ADCB3 ADRB3 BLTC3 BLTR3 DMACNTL3 DMASTAT3
Size Word Word Word Byte Double Word Double Word Double Word Double Word Word Word Word Byte Double Word Double Word Double Word Double Word Word Word Word Byte
Address FF F830h FF F834h FF F83Ch FF F83Eh FF F840h FF F844h FF F848h FF F84Ch FF F850h FF F854h FF F85Ch FF F85Eh FF F860h FF F864h FF F868h FF F86Ch FF F870h FF F874h FF F87Ch FF F87Eh Bus Interface Unit
Access Type Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write
Value After Reset 0000h 0000h 0000h 00h 0000 0000h 0000 0000h 0000 0000h 0000 0000h 0000h 0000h 0000h 00h 0000 0000h 0000 0000h 0000 0000h 0000 0000h 0000h 0000h 0000h 00h
Comments
BCFG IOCFG SZCFG0 SZCFG1 SZCFG2
Byte Word Word Word Word
FF F900h FF F902h FF F904h FF F906h FF F908h
Read/Write Read/Write Read/Write Read/Write Read/Write
07h 069Fh 069Fh 069Fh 069Fh
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Register Name
Size
Address
Access Type
Value After Reset
Comments
System Configuration MCFG DBGCFG MSTAT SWRESET Byte Byte Byte Byte FF F910h FF F912h FF F914h FF F918h Read/Write Read/Write Read Only Write Only 00h 00h ENV2:0 pins N/A
Flash Program Memory Interface FMIBAR FMIBDR FM0WER FM1WER FMCTRL FMSTAT FMPSR FMSTART FMTRAN FMPROG FMPERASE FMMERASE0 FMEND FMMEND FMRCV FMAR0 FMAR1 FMAR2 Word Word Word Word Word Word Byte Byte Byte Byte Byte Byte Byte Byte Byte Word Word Word FF F940h FF F942h FF F944h FF F946h FF F94Ch FF F94Eh FF F950h FF F952h FF F954h FF F956h FF F958h FF F95Ah FF F95Eh FF F960h FF F962h FF F964h FF F966h FF F968h Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Read Only Read Only 0000h 0000h 0000h 0000h 0000h 0000h 04h 18h 30h 16h 04h EAh 18h 3Ch 04h
Flash Data Memory Interface FSMIBAR FSMIBDR FSM0WER FSMCTRL FSMSTAT FSMPSR FSMSTART Word Word Word Word Word Byte Byte FF F740h FF F742h FF F744h FF F74Ch FF F74Eh FF F750h FF F752h Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write 0000h 0000h 0000h 0000h 0000h 04h 18h
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CP3CN23
Register Name FSMTRAN FSMPROG FSMPERASE FSMMERASE0 FSMEND FSMMEND FSMRCV FSMAR0 FSMAR1 FSMAR2
Size Byte Byte Byte Byte Byte Byte Byte Word Word Word
Address FF F754h FF F756h FF F758h FF F75Ah FF F75Eh FF F760h FF F762h FF F764h FF F766h FF F768h
Access Type Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Read Only Read Only
Value After Reset 30h 16h 04h EAh 18h 3Ch 04h
Comments
CVSD/PCM Converter CVSDIN CVSDOUT PCMIN PCMOUT LOGIN LOGOUT LINEARIN LINEAROUT CVCTRL CVSTAT CVTEST CVRADD CVRDAT CVDECOUT CVENCIN CVENCPR Word Word Word Word Byte Byte Word Word Word Word Word Word Word Word Word Word FF FC20h FF FC22h FF FC24h FF FC26h FF FC28h FF FC2Ah FF FC2Ch FF FC2Eh FF FC30h FF FC32h FF FC34h FF FC36h FF FC38h FF FC3Ah FF FC3Ch FF FC3Eh Write Only Read Only Write Only Read Only Write Only Read Only Write Only Read Only Read/Write Read Only Read/Write Read/Write Read/Write Read Only Read Only Read Only 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h
Triple Clock + Reset CRCTRL PRSFC PRSSC PRSAC Byte Byte Byte Byte FF FC40h FF FC42h FF FC44h FF FC46h Read/Write Read/Write Read/Write Read/Write 00X0 0110b 4Fh B6h FFh
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Register Name
Size
Address
Access Type
Value After Reset
Comments
Power Management PMMCR PMMSR Byte Byte FF FC60h FF FC62h Read/Write Read/Write 00h 0000 0XXXb
Multi-Input Wake-Up 0 WK0EDG WK0ENA WK0ICTL1 WK0ICTL2 WK0PND WK0PCL WK0IENA Word Word Word Word Word Word Word FF FC80h FF FC82h FF FC84h FF FC86h FF FC88h FF FC8Ah FF FC8Ch Read/Write Read/Write Read/Write Read/Write Read/Write Write Only Read/Write 00h 00h 00h 00h 00h XXh 00h Bits may only be set; writing 0 has no effect.
Multi-Input Wake-Up 1 WK1EDG WK1ENA WK1ICTL1 WK1ICTL2 WK1PND WK1PCL WK1IENA Word Word Word Word Word Word Word FF FCA0h FF FCA2h FF FCA4h FF FCA6h FF FCA8h FF FCAAh FF FCACh Read/Write Read/Write Read/Write Read/Write Read/Write Write Only Read/Write 00h 00h 00h 00h 00h XXh 00h Bits may only be set; writing 0 has no effect.
General-Purpose I/O Ports PBALT PBDIR PBDIN PBDOUT PBWPU PBHDRV PBALTS PCALT Byte Byte Byte Byte Byte Byte Byte Byte FF FB00h FF FB02h FF FB04h FF FB06h FF FB08h FF FB0Ah FF FB0Ch FF FB10h Read/Write Read/Write Read Only Read/Write Read/Write Read/Write Read/Write Read/Write 00h 00h XXh XXh 00h 00h 00h 00h
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CP3CN23
Register Name PCDIR PCDIN PCDOUT PCWPU PCHDRV PCALTS PEALT PEDIR PEDIN PEDOUT PEWPU PEHDRV PEALTS PFALT PFDIR PFDIN PFDOUT PFWPU PFHDRV PFALTS PGALT PGDIR PGDIN PGDOUT PGWPU PGHDRV PGALTS PHALT PHDIR PHDIN PHDOUT PHWPU PHHDRV PHALTS PJALT PJDIR
Size Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte
Address FF FB12h FF FB14h FF FB16h FF FB18h FF FB1Ah FF FB1Ch FF FCC0h FF FCC2h FF FCC4h FF FCC6h FF FCC8h FF FCCAh FF FCCCh FF FCE0h FF FCE2h FF FCE4h FF FCE6h FF FCE8h FF FCEAh FF FCECh FF F300h FF F302h FF F304h FF F306h FF F308h FF F30Ah FF F30Ch FF F320h FF F322h FF F324h FF F326h FF F328h FF F32Ah FF F32Ch FF F340h FF F342h
Access Type Read Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write
Value After Reset 00h XXh XXh 00h 00h 00h 00h 00h XXh XXh 00h 00h 00h 00h 00h XXh XXh 00h 00h 00h 00h 00h XXh XXh 00h 00h 00h 00h 00h XXh XXh 00h 00h 00h 00h 00h
Comments
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CP3CN23
Register Name PJDIN PJDOUT PJWPU PJHDRV PJALTS
Size Byte Byte Byte Byte Byte
Address FF F344h FF F346h FF F348h FF F34Ah FF F34Ch
Access Type Read Only Read/Write Read/Write Read/Write Read/Write
Value After Reset XXh XXh 00h 00h 00h
Comments
Advanced Audio Interface ARFR ARDR0 ARDR1 ARDR2 ARDR3 ATFR ATDR0 ATDR1 ATDR2 ATDR3 AGCR AISCR ARSCR ATSCR ACCR ADMACR Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word FF FD40h FF FD42h FF FD44h FF FD46h FF FD48h FF FD4Ah FF FD4Ch FF FD4Eh FF FD50h FF FD52h FF FD54h FF FD56h FF FD58h FF FD5Ah FF FD5Ch FF FD5Eh Read Only Read Only Read Only Read Only Read Only Write Only Write Only Write Only Write Only Write Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write 0000h 0000h 0000h 0000h 0000h XXXXh 0000h 0000h 0000h 0000h 0000h 0000h 0004h F003h 0000h 0000h
Interrupt Control Unit IVCT NMISTAT EXNMI ISTAT0 ISTAT1 ISTAT2 IENAM0 IENAM1 IENAM2 Byte Byte Byte Word Word Word Word Word Word FF FE00h FF FE02h FF FE04h FF FE0Ah FF FE0Ch FF FE20h FF FE0Eh FF FE10h FF FE22h Read Only Read Only Read/Write Read Only Read Only Read Only Read/Write Read/Write Read/Write 10h 00h XXXX 00X0b 0000h 0000h 0000h FFFFh FFFFh FFFFh Fixed Addr.
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CP3CN23
Register Name
Size
Address
Access Type
Value After Reset
Comments
Microwire/SPI Interface MWDAT MWCTL1 MWSTAT Word Word Word FF F3A0h FF F3A2h FF F3A4h Read/Write Read/Write Read Only XXXXh 0000h All implemented bits are 0
UART0 U0TBUF U0RBUF U0ICTRL U0STAT U0FRS U0MDSL1 U0BAUD U0PSR U0OVR U0MDSL2 U0SPOS Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte FF F200h FF F202h FF F204h FF F206h FF F208h FF F20Ah FF F20Ch FF F20Eh FF F210h FF F212h FF F214h UART1 U1TBUF U1RBUF U1ICTRL U1STAT U1FRS U1MDSL1 U1BAUD U1PSR U1OVR U1MDSL2 U1SPOS Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte FF F220h FF F222h FF F224h FF F226h FF F228h FF F22Ah FF F22Ch FF F22Eh FF F230h FF F232h FF F234h Read/Write Read Only Read/Write Read only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXh XXh 01h 00h 00h 00h 00h 00h 00h 00h 06h Bits 0:1 read only Read/Write Read Only Read/Write Read only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXh XXh 01h 00h 00h 00h 00h 00h 00h 00h 06h Bits 0:1 read only
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CP3CN23
Register Name
Size
Address
Access Type
Value After Reset
Comments
UART2 U2TBUF U2RBUF U2ICTRL U2STAT U2FRS U2MDSL1 U2BAUD U2PSR U2OVR U2MDSL2 U2SPOS Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte FF F240h FF F242h FF F244h FF F246h FF F248h FF F24Ah FF F24Ch FF F24Eh FF F250h FF F252h FF F254h UART3 U3TBUF U3RBUF U3ICTRL U3STAT U3FRS U3MDSL1 U3BAUD U3PSR U3OVR U3MDSL2 U3SPOS Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte Byte FF F260h FF F262h FF F264h FF F266h FF F268h FF F26Ah FF F26Ch FF F26Eh FF F270h FF F272h FF F274h Read/Write Read Only Read/Write Read only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXh XXh 01h 00h 00h 00h 00h 00h 00h 00h 06h Bits 0:1 read only Read/Write Read Only Read/Write Read only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXh XXh 01h 00h 00h 00h 00h 00h 00h 00h 06h Bits 0:1 read only
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CP3CN23
Register Name
Size
Address
Access Type
Value After Reset
Comments
ACCESS.bus
ACBSDA ACBST ACBCST ACBCTL1 ACBADDR ACBCTL2 ACBADDR2 ACBCTL3
Byte Byte Byte Byte Byte Byte Byte Byte
FF F2A0h FF F2A2h FF F2A4h FF F2A6h FF F2A8h FF F2AAh FF F2ACh FF F2AEh
Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write
XXh 00h 00h 00h XXh 00h XXh 00h
Timing and Watchdog TWCFG TWCP TWMT0 T0CSR WDCNT WDSDM Byte Byte Word Byte Byte Byte FF FF20h FF FF22h FF FF24h FF FF26h FF FF28h FF FF2Ah Read/Write Read/Write Read/Write Read/Write Write Only Write Only 00h 00h FFFFh 00h 0Fh 5Fh
Multi-Function Timer TCNT1 TCRA TCRB TCNT2 TPRSC TCKC TCTRL TICTL TICLR Word Word Word Word Byte Byte Byte Byte Byte FF FF40h FF FF42h FF FF44h FF FF46h FF FF48h FF FF4Ah FF FF4Ch FF FF4Eh FF FF50h Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write XXh XXh XXh XXh 00h 00h 00h 00h 00h
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CP3CN23
Register Name
Size
Address
Access Type
Value After Reset
Comments
Versatile Timer Unit MODE IO1CTL IO2CTL INTCTL INTPND CLK1PS COUNT1 PERCAP1 DTYCAP1 COUNT2 PERCAP2 DTYCAP2 CLK2PS COUNT3 PERCAP3 DTYCAP3 COUNT4 PERCAP4 DTYCAP4 Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word Word FF FF80h FF FF82h FF FF84h FF FF86h FF FF88h FF FF8Ah FF FF8Ch FF FF8Eh FF FF90h FF FF92h FF FF94h FF FF96h FF FF98h FF FF9Ah FF FF9Ch FF FF9Eh FF FFA0h FF FFA2h FF FFA4h ADC ADCGCR ADCACR ADCCNTRL ADCSTART ADCSCDLY ADCRESLT ADCSMBC0 ADCSMBC1 ADCSMBC2 ADCSMBC3 ADCSMSH Word Word Word Word Word Word Word Word Word Word Word FF F3C0h FF F3C2h FF F3C4h FF F3C6h FF F3C8h FF F3CAh FF F3CEh FF F3D0h FF F3D2h FF F3D4h FF F3D6h Read/Write Read/Write Read/Write Write Only Read/Write Read Only Read/Write Read/Write Read/Write Read/Write Read/Write 0000h 0000h 0000h N/A 0000h 0000h 1483h 24E6h 2508h 314Ah 01A2h Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h 0000h
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CP3CN23
Register Name
Size
Address
Access Type
Value After Reset
Comments
RNG RNGCST RNGD RNGDIVH RNGDIVL Word Word Word Word FF F280h FF F282h FF F284h FF F286h Read/Write Read/Write Read/Write Read/Write 0000h 0000h 0000h 0000h
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CP3CN23
27.0 Register Bit Fields
The following tables show the functions of the bit fields of the device registers. For more information on using these registers, see the detailed description of the applicable function elsewhere in this data sheet.
CAN Control/ Status CGCRn CTIMn GMSKBn GMSKXn BMSKBn BMSKXn CIENn CIPNDn CICLRn CICENn CSTPNDn CANECn CEDIAGn CTMRn
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved PSC[6:0]
EIT
DIAG INTE LOOP IGN EN RNAL BACK ACK SJW[1:0]
LO
DD IR
TST BUFF CAN CRX CTX PEN LOCK EN TSEG2[2:0] IDE GM[17:15] XRTR RTR IDE BM[17:15] XRTR
TSEG1[3:0] RTR
GM[28:18] GM[14:0] BM[28:18] BM[14:0] EI EN EI PND EI CLR EI CEN Reserved REC[7:0] Res. DRI STU MON CRC TXE VE FF EBID[5:0] CTMR[15:0] IEN[14:0] IPND[14:0] ICLR[14:0] ICEN[14:0] NS[2:0]
IRQ TEC[7:0]
IST[3:0]
EFID[3:0]
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CAN Memory Registers CMBn.ID1 CMBn.ID0 CMBn.DATA0 CMBn.DATA1 CMBn.DATA2 CMBn.DATA3 CMBn.TSTP
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
XI28 XI27 XI26 XI25 XI24 XI23 XI22 XI21 XI20 XI19 XI18 SRR IDE ID10 ID9 ID8 ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0 RTR XI14 XI13 XI12 XI11 XI10 XI9 XI8 XI7 XI6 XI5 XI4 XI3 XI2
XI17 XI16 XI15 XI1 XI0 RTR
Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.0 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0 Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data 3.7 3.6 3.5 3.4 3.3 3.2 3.1 3.0 4.7 4.6 4.5 4.4 4.3 4.2 4.1 4.0 Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data 5.7 5.6 5.5 5.4 5.3 5.2 5.1 5.0 6.7 6.6 6.5 6.4 6.3 6.2 6.1 6.0 Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data Data 7.7 7.6 7.5 7.4 7.3 7.2 7.1 7.0 8.7 8.6 8.5 8.4 8.3 8.2 8.1 8.0 TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP TSTP 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Reserved PRI3 PRI2 PRI1 PRI0 ST3 ST2 ST1 ST0
CMBn.CNTSTAT DLC3 DLC2 DLC1 DLC0
DMAC 20..16 15 Registers ADCA ADRA ADCB ADRB BLTC BLTR DMACNTL DMASTAT N/A N/A N/A Res.
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Device A Address Counter Device A Address Device B Address Counter Device B Address Block Length Counter Block Length INCB ADB N/A INCA ADA SW Res. RQ OT DIR IND TCS VLD EO VR ETC CH EN TC
Reserved
CH OVR AC
203
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CP3CN23
System Configuration Registers MCFG DBGCFG MSTAT
7
6
5
4
3
2
1
0
Reserved
MEM_IO_ MISC_IO_ Reserved SPEED SPEED Reserved
SCLKOE
MCLKOE PLLCLKOE FREEZE
EXIOE ON OENV0
ISPRST
WDRST Reserved
DPGM BUSY
PGMBUSY
OENV2
OENV1
BIU Registers BCFG IOCFG SZCFG0 SZCFG1 SZCFG2
15
12
11
10
9
8
7
6
5
4
3
2
1
0 EWR
Reserved Reserved Reserved Reserved Reserved IPST Res. BW BW BW BW Reserved WBR RBE WBR RBE WBR RBE HOLD HOLD HOLD HOLD WAIT WAIT WAIT WAIT
FRE IPRE IPST Res. FRE IPRE IPST Res. FRE IPRE IPST Res.
TBI Register TMODE
7
6 Reserved
5
4 TSTEN
3 ENMEM
2
1 TMSEL
0
Flash Program Memory Interface Registers FMIBAR FMIBDR FM0WER FM1WER FM2WER FM3WER FMCTRL FMSTAT FMPSR FMSTART FMTRAN
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved IBD FM0WE FM1WE FM2WE FM3WE Reserved Reserved Reserved Reserved Reserved MER PER PE
IBA
IENP DIS LOW Res. CWD ROG VRF PRW FM DE FM PERR EERR RR FULL BUSY FTDIV FTSTART FTTRAN
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Flash Program Memory Interface Registers FMPROG FMPERASE FMMERASE0 FMEND FMMEND FMRCV FMAR0 FMAR1 FMAR2
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved Reserved Reserved Reserved Reserved Reserved Reserved WRPROT RDPROT ISPE CADR15:0 EMPTY
FTPROG FTPER FTMER FTEND FTMEND FTRCV Res. BOOTAREA
Flash Data Memory Interface Registers FSMIBAR FSMIBDR FSM0WER FSM1WER FSM2WER FSM3WER FSMCTRL FSMSTAT FSMPSR FSMSTART FSMTRAN FSMPROG FSMPERASE FSMMERASE0 FSMEND FSMMEND FSMRCV
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved IBD FM0WE FM1WE FM2WE FM3WE Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved MER PER PE
IBA
IENP DIS LOW Res. CWD ROG VRF PRW DE FM FM PE RR FULL BUSY RR FTDIV FTSTART FTTRAN FTPROG FTPER FTMER FTEND FTMEND FTRCV EE RR
205
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Flash Data Memory Interface Registers FSMAR0 FSMAR1 FSMAR2
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved WRPROT RDPROT ISPE CADR15:0 EMPTY BOOTAREA
Res.
CVSD/PCM Registers CVSDIN CVSDOUT PCMIN PCMOUT LOGIN LOGOUT LINEARIN LINEAROUT CVCTRL
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CVSDIN CVSDOUT PCMIN PCMOUT Reserved Reserved LINEARIN LINEAROUT Reserved PCM CO NV CVSD CONV CVS DMA DMA DMA DMA CVS PCM CLK DER PI PO CI CO DINT INT EN RINT CVINST CVF CVE PCM CVN INT F RT CV EN CV NE TB LOGIN LOGOUT
CVSTAT CVTEST CVRADD CVRDAT CVDECOUT CVENCIN CVENCPR
Reserved
CVOUTST Reserved Reserved CVRDAT
TEST ENC DEC _VAL _IN _EN CVRADD
CVDECOUT CVENCIN CVENCPRT
CLK3RES Registers CRCTRL PRSFC PRSSC PRSAC
7 Reserved Reserved
6
5 POR MODE
4 ACE2
3 ACE1
2 PLLPWD
1 FCLK
0 SCLK
FCDIV SCDIV
ACDIV2
ACDIV1
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PMM Register PMMCR PMMSR
7 HCCH
6 HCCM
5 DHC Reserved
4 DMC
3 WBPSM
2 HALT OHC
1 IDLE OMC
0 PSM OLC
MIWU16 Registers WKEDG WKENA WKICTL1 WKICTL2 WKPND WKPCL WKIENA
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WKED WKEN WKINTR7 WKINTR6 WKINTR5 WKINTR4 WKINTR3 WKINTR2 WKINTR1 WKINTR9 WKINTR0 WKINTR8
WKINTR15 WKINTR14 WKINTR13 WKINTR12 WKINTR11 WKINTR10 WKPD WKCL WKIEN
GPIO Registers PxALT PxDIR PxDIN PxDOUT PxWPU PxHDRV PxALTS
7
6
5
4
3
2
1
0
Px Pins Alternate Function Enable Px Port Direction Px Port Output Data Px Port Input Data Px Port Weak Pull-Up Enable Px Port High Drive Strength Enable Px Pins Alternate Function Source Selection
AAI Registers ARSR ATSR ARFR ARDR0 ARDR1 ARDR2 ARDR3 ATFR ATDR0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ARSH ATSH ARFH ARDH ARDH ARDH ARDH ATFH ATDH
ARSL ATSL ARFL ARDL ARDL ARDL ARDL ATFL ATDL
207
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AAI Registers ATDR1 ATDR2 ATDR3 AGCR AISCR ARSCR ATSCR ACCR ADMACR
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATDH ATDH ATDH CLK EN AAI IOM2 IFS EN Reserved RXFWM TXFWM BCPRS Reserved ACO ACD TMD FSL TX EIC TX IC CTF CRF IEBC FSS IEFS RX EIC RX IC TX EIP TX IP RX EIP
ATDL ATDL ATDL SCS RX IP TX EIE LPB DWL ASS TX IE RX EIE RX IE RX AF
RXDSA TXDSA
RXSA TXSA FCPRS
RXO RXE RXF
TXU TXF TXE TXAE CSS RMD
ICU Registers IVCT ISTAT0 ISTAT1 IENAM0 IENAM1
15 . . . 12 11 . . . 8 Reserved
7 0
6 0
5
4
3
2
1
0
INTVECT[5:0] IST(15:0) IST(31:16) IENA(15:0) IENA(31:16)
UART Registers UnTBUF UnRBUF UnICTRL UnSTAT UnFRS UnMDSL1 UnBAUD UnPSR UnOVR UnMDSL2 UnSPOS
7
6
5
4 UnTBUF URBUF
3
2
1
0
UEEI Reserved Reserved URTS
UERI UXMIP UPEN UFCE
UETI URB9
UEFCI UBKD
UCTS UERR UXB9 UCKS
UDCTS UDOE USTP UBRK
URBF UFE
UTBE UPE
UPSEL UERD UETD
UCHAR UATN UMOD
UDIV7:0 UPSC Reserved Reserved Reserved USAMP UDIV10:8 UOVSR USMD
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MWSPI16 Registers MWDAT MWCTL1 MWSTAT
15 . . . 9
8
7
6
5 MWDAT
4
3
2
1
0
SCDV
SCIDL
SCM
EIW
EIR
EIO
ECHO
MOD OVR
MNS RBF
MWEN BSY
Reserved
ACB Registers ACBSDA ACBST ACBCST ACBCTL1 ACBADDR ACBCTL2 ACBADDR2 ACBCTL3
7
6
5
4 DATA
3
2
1
0
SLVSTP
SDAST
BER TGSCL GCMEN
NEGACK TSDA ACK
STASTR GMATCH Reserved ADDR
NMATCH MATCH INTEN
MASTER BB STOP
XMIT BUSY START
ARPMATCH MATCHAF STASTRE SAEN NMINTE
SCLFRQ[6:0] SAEN Reserved ADDR ARPEN
ENABLE
SCLFRQ[8:7]
TWM Registers TWCFG TWCP TWMT0 T0CSR WDCNT WDSDM
15 . . . 8 Reserved Reserved
7
6
5
4
3
2
1
0
Reserved
WDSDME WDCT0I LWDCNT LTWMT0 LTWCP LTWCFG Reserved PRESET MDIV
Reserved Reserved Reserved
Reserved
FRZT0E WDTLD PRESET RSTDATA
T0INTE
TC
RST
MFT16 Registers TCNT1 TCRA TCRB TCNT2 TPRSC TCKC TCTRL TICTL TICLR
15 . . . 8
7
6
5
4 TCNT1 TCRA TCRB TCNT2
3
2
1
0
Reserved Reserved Reserved Reserved Reserved
Reserved Reserved TEN TDIEN TAOUT TCIEN TBEN TBIEN C2CSEL TAEN TAIEN TBEDG TDPND TDCLR
CLKPS C1CSEL TAEDG TCPND TCCLR TMDSEL TBPND TBCLR TAPND TACLR
Reserved
209
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VTU Registers MODE IO1CTL IO2CTL INTCTL INTPND CLK1PS COUNT1 PERCAP1 DTYCAP1 COUNT2 PERCAP2 DTYCAP2 CLK2PS COUNT3 PERCAP3 DTYCAP3 COUNT4 PERCAP4 DTYCAP4
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TMOD4 P4 POL P7 POL
T8 T7 RUN RUN C4EDG C7EDG
TMOD3 P3 POL P6 POL
T6 T5 RUN RUN C3EDG C6EDG
TMOD2 P2 POL P5 POL
T4 T3 RUN RUN C2EDG C5EDG
TMOD1 P1 POL P5 POL
T2 T1 RUN RUN C1EDG C5EDG
I4DEN I4CEN I4BEN I4AEN I3DEN I3CEN I3BEN I3AEN I2DEN I2CEN I2BEN I2AEN I1DEN I1CEN I1BEN I1AEN I4DPD I4CPD I4BPD I4APD I3DPD I3CPD I3BPD I3APD I2DPD I2CPD I2BPD I2APD I1DPD I1CPD I1BPD I1APD C2PRSC CNT1 PCAP1 DCAP1 CNT2 PCAP2 DCAP2 C4PRSC CNT3 PCAP3 DCAP3 CNT4 PCAP4 DCAP4 C3PRSC C1PRSC
ADC Registers ADCGCR ADCACR ADCCNTRL ADCSTART ADCSCDLY ADCRESLT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MUXINTEN Res. NREF_CFG PREF_CFG OUTEN CNVT TRG PRM Reserved
TOUCH_CFG Reserved
MUX_CFG
DIFF ADCIN CLKEN CLKDIV CLKSEL
AUTO EXT POL
Write any value. ADC_DIV ADC_ ADC_ PEN_ SIGN DONE OFLW DOWN ADC_DELAY1 ADC_RESULT ADC_DELAY2
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210
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RNG Registers RNGCST RNGD RNGDIVH RNGDIVL
15
14
13
12
11
10
9
8
7
6
5 IMSK
4
3 Reserved
2
1
0
Reserved RNGD Reserved RNGDIV15:0
DVALID RNGE
RNGDIV17:16
211
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28.0 Electrical Characteristics
28.1 ABSOLUTE MAXIMUM RATINGS
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply voltage (VCC) All input and output voltages with respect to GND* ESD protection level Allowable sink/source current per signal pin TBD -0.5V to IOVCC + 0.5V 2 kV (Human Body Model) 10 mA Total current into IOVCC pins Total current into VCC pins (source) Total current out of GND pins (sink) Latch-up immunity Storage temperature range 200 mA 200 mA 200 mA 200 mA -65C to +150C
Note: Absolute maximum ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications are not ensured when operating the device at absolute maximum ratings. * The latch-up tolerance on Access Bus pins 14 and 15 exceeds 150mA.
28.2
DC ELECTRICAL CHARACTERISTICS (Temperature: -40C TA +85C)
Symbol Vcc IOVcc AVcc ADVcc UVcc VIL VIH Vxl1 Vxh1 Vxl2 Vxh2 Vrstl Vrsth Vhys IOH IOL IOLACB IOLTS IOHTS IOHW IL
Parameter Digital Logic Supply Voltage I/O Supply Voltage Analog PLL Supply Voltage ADC Supply Voltage USB Supply Voltage Logical 0 Input Voltage (except X1CKI, X2CKI, and RESET) Logical 1 Input Voltage (except X1CKI, X2CKI, and RESET) X1CKI Logical 0 Input Voltage X1CKI Logical 1 Input Voltage X2CKI Logical 0 Input Voltage X2CKI Logical 1 Input Voltage RESET Logical 0 Input Voltage RESET Logical 1 Input Voltage Hysteresis Loop Width
a
Conditions 2.25 2.25 2.25 2.25 3.0 -0.5
Min 2.75 3.63 2.75 2.75 3.63
Max
Units V V V V V V V V V V V V V V mA mA mA mA mA
0.3 Vcc IOVcc + 0.5 0.3 Vcc Vcc + 0.5 0.6 Vcc + 0.5 0.4
0.7 IOVcc External X1 clock External X1 clock External X2 clock External X2 clock RESET input RESET input -0.5 0.7 Vcc -0.5 0.7 Vcc -0.5 1.7 0.1 IOVcc VOH = 1.8V, IOVcc = 2.25V VOL = 0.45V, IOVcc = 2.25V VOL = 0.4V, IOVcc = 2.25V VOL = 0.15V, ADVcc = 2.25V VOH = 2.1, ADVcc = 2.25V VIL = 0V, IOVcc = 3.63V 0V Vin IOVcc -6 6 3 18 -18 -20 -2.0
Logical 1 Output Current Logical 0 Output Current SDA, SCL Logical 0 Output Current Touchscreen Logical 0 Output Current (for ADC2/TSX- and ADC3/TSY-) Touchscreen Logical 1 Output Current (for ADC0/TSX+ and ADC1/TSY+) Weak Pull-up Current High Impedance Input Leakage Current
-300 2.0
A A
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Symbol IO(Off) Icca1 Iccprog Iccps Iccid Iccq
Parameter Output Leakage Current (I/O pins in input mode) Digital Supply Current Active Mode b Digital Supply Current Active Mode c Digital Supply Current Power Save Mode d Digital Supply Current Idle Mode e Digital Supply Current Halt Mode e,f
Conditions 0V Vout Vcc Vcc = 2.75V, IOVcc=3.63V Vcc = 2.75V, IOVcc = 3.63V Vcc = 2.75V, IOVcc =3.63V Vcc = 2.75V, IOVcc = 3.63V Vcc = 2.75V, IOVcc = 3.63V, 20C -2.0
Min 2.0 20 20 4 2 150
Max
Units A mA mA mA mA A
a. Guaranteed by design b. Run from internal memory (RAM), Iout = 0 mA, X1CKI = 12 MHz, PLL enabled (4x), internal system clock is 24 MHz, not programming Flash memory c. Same conditions as Icca1, but programming or erasing Flash memory page d. Running from internal memory (RAM), Iout = 0 mA, XCKI1 = 12 MHz, PLL disabled, X2CKI = 32.768 kHz, device put in power-save mode, Slow Clock derived from XCKI1 e. Iout = 0 mA, XCKI1 = Vcc, X2CKI = 32.768 kHz f. Halt current approximately doubles for every 20C.
28.3
ADC ELECTRICAL CHARACTERISTICS (Temperature: -40C TA +85C)
Symbol VPREF VNREF
Parameter ADC Positive Reference Input ADC Negative Reference Input ADC Input Range Clock Frequency
Conditions
Min 2 0 VNREF
Typ
Max 2.75 0.25 VPREF
Units V V V MHz s
12 14 2 0.7 9 8 0.1 50 8 0.2 20 10 12 100 10 0.6
tC INL DNL CADCIN CADCINS RADCIN CADCIN CADCINS RADCIN
Conversion Time (12-bit result) Integral Non-Linearity Differential Non-Linearity Total Capacitance of ADC Input Switched Capacitance of ADC Input Resistance of ADC Input Path Total Capacitance of ADC Reference Input Switched Capacitance of ADC Reference Input Resistance of ADC Reference Input Path
LSB LSB pF pF kohm pF pF kohm
213
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28.4
Symbol tSTART tTRAN tPROG tPERASE tMERASE tEND tMEND tRCV tHV tHV
FLASH MEMORY ON-CHIP PROGRAMMING
Parameter Program/Erase to NVSTR Setup Time (NVSTR = Non-Volatile Storage NVSTR to Program Setup Timeb Programming Pulse Width Page Erase Pulse Width
f g d e c a
Conditions
Min 5 10 20 20 200 5 100 1
Max 40 8 4 -
Units s s s ms ms s s s ms ms cycles years
Module Erase Pulse Width NVSTR Hold Time
h
NVSTR Hold Time (Module Erase) Recovery Time
Cumulative Program High Voltage Period For Each Row After Erasei Write/Erase Endurance Data Retention
128K program blocks 8K data block
20,000
25C
100
a. Program/erase to NVSTR Setup Time is determined by the following equation: tSTART = Tclk x (FTDIV + 1) x (FTSTART + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTSTART is the contents of the FMSTART or FSMSTART register b. NVSTR to Program Setup Time is determined by the following equation: tTRAN = Tclk x (FTDIV + 1) x (FTTRAN + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTTRAN is the contents of the FMTRAN or FSMTRAN register c. Programming Pulse Width is determined by the following equation: tPROG = Tclk x (FTDIV + 1) x 8 x (FTPROG + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTPROG is the contents of the FMPROG or FSMPROG register d. Page Erase Pulse Width is determined by the following equation: tPERASE = Tclk x (FTDIV + 1) x 4096 x (FTPER + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTPER is the contents of the FMPERASE or FSMPERASE register e. Module Erase Pulse Width is determined by the following equation: tMERASE = Tclk x (FTDIV + 1) x 4096 x (FTMER + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTMER is the contents of the FMMERASE0 or FSMMERASE0 register f. NVSTR Hold Time is determined by the following equation: tEND = Tclk x (FTDIV + 1) x (FTEND + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTEND is the contents of the FMEND or FSMEND register g. NVSTR Hold Time (Module Erase) is determined by the following equation: tMEND = Tclk x (FTDIV + 1) x 8 x (FTMEND + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTMEND is the contents of the FMMEND or FSMMEND register h. Recovery Time is determined by the following equation: tRCV = Tclk x (FTDIV + 1) x (FTRCV + 1), where Tclk is the System Clock period, FTDIV is the contents of the FMPSR or FSMPSR register, and FTRCV is the contents of the FMRCV or FSMRCV register i. Cumulative program high voltage period for each row after erase tHV is the accumulated duration a flash cell is exposed to the programming voltage after the last erase cycle.
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28.5
The RESET and NMI input pins are active during the Power Save mode. In order to guarantee that the Power Save curAll output signals are powered by the digital supply (VCC). rent not exceed 1 mA, these inputs must be driven to a voltTable 73 summarizes the states of the output signals during age lower than 0.5V or higher than VCC - 0.5V. An input the reset state (when VCC power exists in the reset state) voltage between 0.5V and (VCC - 0.5V) may result in power and during the Power Save mode. consumption exceeding 1 mA. Table 73 Output Pins During Reset and Power-Save Signals on a Pin PB7:0 PC7:0 PE5:0 PF7:0 PG7:0 PH7:0 PJ7:0 Reset State (with Vcc) TRI-STATE TRI-STATE TRI-STATE TRI-STATE TRI-STATE TRI-STATE TRI-STATE Power Save Mode Previous state Previous state Previous state Previous state Previous state Previous state Previous state Comments I/O ports will maintain their values when entering power-save mode
OUTPUT SIGNAL LEVELS
28.6
CLOCK AND RESET TIMING
Table 74 Clock and Reset Signals
Symbol Figure
Description
Reference Clock Input Signals
Min (ns)
Max (ns)
tX1p tX1h tX1l tX2p tX2h tX2l tIH
92 92 92 92 92 92 93
X1 period X1 high time, external clock X1 low time, external clock X2 perioda X2 high time, external clock X2 low time, external clock Input hold time (NMI, RXD1, RXD2)
Rising Edge (RE) on X1 to next RE on X1 At 2V level (Both Edges) At 0.8V level (Both Edges) RE on X2 to next RE on X2 At 2V level (both edges) At 0.8V level (both edges) After RE on CLK
83.33 (0.5 Tclk) - 5 (0.5 Tclk) - 5 10,000 (0.5 Tclk) - 500 (0.5 Tclk) - 500 0
83.33
Reset and NMI Input Signals tIW tRST tR 93 94 94 NMI Pulse Width RESET Pulse Width Vcc Rise Time NMI Falling Edge (FE) to RE RESET FE to RE 0.1 Vcc to 0.9 Vcc 20 100
a. Only when operating with an external square wave on X2CKI; otherwise a 32 kHz crystal network must be used between X2CKI and X2CKO. If Slow Clock is internally generated from Main Clock, it may not exceed this given limit.
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tX1p
X1CKI
tX1h
tX1l
tX2p
X2CKI
tX2h
tX2l DS095
Figure 92.
Clock Timing
CLK
tlS NMI
tIW
tlH
DS096
Figure 93.
NMI Signal Timing
CLK
tRST RESET
DS097
Figure 94. Non-Power-On Reset
0.9 VCC VCC 0.1 VCC
tR
DS115
Figure 95.
Power-On Reset
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28.7
UART TIMING
Table 75 UART Signals
Symbol Figure
Description
Reference UART Input Signals
Min (ns)
Max (ns)
tIs tIh
96 96
Input setup time RXD (asynchronous mode) Input hold time RXD (asynchronous mode)
Before Rising Edge (RE) on CLK After RE on CLK UART Output Signals
-
tCOv1 tTXD
96 96
TXD output valid (all signals with propagation delay from CLK RE) TXD output valid
After RE on CLK After RE on CLK
40
1 CLK
2
1
2
1
2
1
2
1
2
1
2
tCOv1
tCOv1
TXD
tlS RXD tlH DS098
Figure 96. UART Asynchronous Mode Timing
217
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28.8
I/O PORT TIMING
Table 76 I/O Port Signals
Symbol Figure
Description
Reference I/O Port Input Signals
Min (ns)
Max (ns)
tIS tIH
97 97
Input Setup Time Input Hold Time
Before Rising Edge (RE) on System Clock After RE on System Clock I/O Port Output Signals
-
tCOv1 tOF
97 97
Output Valid Time Output Floating Time
After RE on System Clock After RE on System Clock
-
1 CLK
2
1
2
1
2
1
2
1
2
1
2
tIS PORTS B, C (input) tlH PORTS B, C (output) tCOv1 tCOv1 DS100 tOF
Figure 97. I/O Port Timing
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28.9
ADVANCED AUDIO INTERFACE (AAI) TIMING
Table 77 Advanced Audio Interface (AAI) Signals
Symbol Figure
Description
Reference AAI Input Signals
Min (ns)
Max (ns)
tRDS tRDH tFSS tFSH
98, 100 98, 100 98 98
Receive Data Setup Time Receive Data Hold Time Frame Sync Setup Time Frame Sync Hold Time
Before Falling Edge (FE) on SRCLK After FE on SRCLK Before Rising Edge (RE) on SRCLK After RE on SRCLK AAI Output Signals
20 20 20 20
-
tCP tCL tCH tFSVH tFSVL tTDV
98 98 98 98, 100 98, 100 99, 101
Receive/Transmit Clock Period Receive/Transmit Low Time Receive/Transmit High Time Frame Sync Valid High Frame Sync Valid Low Transmit Data Valid
RE on SRCLK/SCK to RE on SRCLK/SCK FE on SRCLK/SCK to RE on SRCLK/SCK RE on SRCLK/SCK to FE on SRCLK/SCK RE on SRCLK/SCK to RE on SRFS/SFS RE on SRCLK/SCK to FE on SRFS/SFS RE on SCK to STD Valid
976.6 488.3 488.3 -
20 20 20
tCP
SRCLK
0
1 tCH tCL
2
SRFS tFSVH tFSVL
SRD
0
1
tRDS
tRDH DS116
Figure 98. Receive Timing, Short Frame Sync
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SCK
0
1
2
SFS
STD
0
1
tTDV DS117
Figure 99.
Transmit Timing, Short Frame Sync
SRCLK
0
1
2
N
SRFS tFSVH tFSVL
SRD
0
1
tRDS
tRDH DS118
Figure 100.
Receive Timing, Long Frame Sync
SCK
0
1
2
N
SFS
STD
0
1
tTDV DS119
Figure 101.
Transmit Timing, Long Frame Sync
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220
CP3CN23
28.10
MICROWIRE/SPI TIMING
Table 78 Microwire/SPI Signals
Symbol Figure
Description
Reference Microwire/SPI Input Signals
Min (ns)
Max (ns)
tMSKh tMSKl
102 102 102
Microwire Clock High Microwire Clock Low
At 2.0V (both edges) At 0.8V (both edges) SCIDL bit = 0; Rising Edge (RE) MSK to next RE MSK SCIDL bit = 1; Falling Edge (FE) MSK to next FE MSK After MWCS goes inactive Before MWCS goes active SCIDL bit = 0: After FE MSK SCIDL bit = 1: After RE MSK SCIDL bit = 0: Before RE MSK SCIDL bit = 1: Before FE MSK Normal Mode: After RE MSK Alternate Mode: After FE MSK Normal Mode: After RE MSK Alternate Mode: After FE MSK Normal Mode: Before RE MSK Alternate Mode: Before FE MSK Microwire/SPI Output Signals
80 80
-
tMSKp 103 tMSKh tMSKs 102 102 102 tMWCSh 103 102 tMWCSs 103 102
Microwire Clock Period
200 40 80 40 80 0 40 80 -
MSK Hold (slave only) MSK Setup (slave only)
MWCS Hold (slave only)
MWCS Setup (slave only)
Microwire Data In Hold (master) 104 tMDIh 102 Microwire Data In Hold (slave) 104 102 tMDIs 104 Microwire Data In Setup
tMSKh tMSKl
102 102 102
Microwire Clock High Microwire Clock Low
At 2.0V (both edges) At 0.8V (both edges) SCIDL bit = 0: Rising Edge (RE) MSK to next RE MSK SCIDL bit = 1: Falling Edge (FE) MSK to next FE MSK Data Out Bit #7 Valid After RE on MWCS Normal Mode: After FE MSK Alternate Mode: After RE MSK After FE on MWCS
40 40
-
tMSKp 103 tMSKd tMDOf 102 102 102 tMDOh 103 tMDOnf 106
Microwire Clock Period
100 0.5 tMSK 1.5 tMSK 25 0.0
MSK Leading Edge Delayed (master only) Microwire Data Float b (slave only)
Microwire Data Out Hold
Microwire Data No Float (slave only)
0
25
221
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CP3CN23
Table 78 Microwire/SPI Signals Symbol Figure Description Reference Normal Mode: After FE on MSK Alternate Mode: After RE on MSK Propagation Time Value is the same in all clocking modes of the Microwire Min (ns) Max (ns)
tMDOv
102
Microwire Data Out Valid
25
tMITOp
106
MDODI to MDIDO (slave only)
25
tMSKp
MSK tMSKh tMSKl
tMSKs
tMSKhd
Data In
msb
lsb
tMDls
tMDlh
MDIDO (slave) tMDOf
msb tMDOv tMDOh
lsb
tMDOff
MDODI (master)
msb
lsb
tMSKd MCS (slave) tMCSs tMCSh
DS101
Figure 102. Microwire Transaction Timing, Normal Mode, SCIDL = 0
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tMSKp
MSK tMSKh tMSKs tMSKh tMSKhd
Data In
msb
lsb
tMDls
tMDlh
MDIDO (slave) tMDOf
msb tMDOv tMDOh
lsb tMDOf
MDODO (master)
msb
lsb
MCS (slave)
tMCSs
tMCSh DS102
Figure 103. Microwire Transaction Timing, Normal Mode, SCIDL = 1
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tMSKp
MSK tMSKs tMSKh tMSKl tMSKhd
Data In
msb
lsb
tMDls
tMDlh
MDIDO (slave) tMDOf
msb
lsb
tMDOv tMDOh
tMDOf
MDODO (master)
msb
lsb
MCS (slave) tMCSs tMCSh DS103
Figure 104.
Microwire Transaction Timing, Alternate Mode, SCIDL = 0
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tMSKp
MSK tMSKhd tMSKs tMSKh Data In msb tMSKh lsb
tMDls
tMDlh
MDIDO (slave) tMDOf
msb
lsb
tMDOv tMDOh tMDOff
MDODI (master)
msb
lsb
tSKd MCS (slave only)
tMCSs
tMCSh
DS104
Figure 105.
Microwire Transaction Timing, Alternate Mode, SCIDL = 1
tMSKp
MSK
tMSKs
tMSKhd tMSKh tMSKl
MDODI (slave) tMDls tMITOp
Dl msb tMDlh
Dl lsb
tMITOp
MDIDO (slave) tMDOnf
DO msb
DO lsb
tMDOf
MCS
tMCSs
tMCSh
DS105
Figure 106. Microwire Transaction Timing, Data Echoed to Output, Normal Mode, SCIDL = 0, ECHO = 1, Slave Mode
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28.11
ACCESS.BUS TIMING
Table 79 ACCESS.bus Signals
Symbol Figure
Description
Reference ACCESS.bus Input Signals
Min (ns)
Max (ns)
tBUFi tCSTOsi tCSTRhi tCSTRsi tDHCsi tDLCsi tSCLfi tSCLri tSCLlowi tSCLhighi tSDAri tSDAfl tSDAhi tSDAsi
108 108 108 108 109 108 107 107 110 110 107 107 110 110
Bus free time between Stop and Start Condition SCL setup time SCL hold time SCL setup time Data High setup time Data Low setup time SCL signal rise time SCL signal fall time SCL low time SCL high time SDA signal rise time SDA signal fall time SDA hold time SDA setup time After SCL FE Before SCL RE ACCESS.bus Output Signals After SCL Falling Edge (FE) After SCL RE Before Stop Condition After Start Condition Before Start Condition Before SCL Rising Edge (RE) Before SCL RE
tSCLhigho (8 x tCLK) - tSCLri (8 x tCLK) - tSCLri (8 x tCLK) - tSCLri 2 x tCLK 2 x tCLK 16 x tCLK 16 x tCLK 0 2 x tCLK
300 1000 1000 300 -
tBUFo tCSTOso tCSTRho tCSTRso tDHCso tDLCso tSCLfo tSCLro tSCLlowo tSCLhigh
o
108 108 108 109 109 108 107 107 110 110 107 107 110 110
Bus free time between Stop and Start Condition SCL setup time SCL hold time SCL setup time Data High setup time Data Low setup time SCL signal Fall time SCL signal Rise time SCL low time SCL high time SDA signal Fall time SDA signal Rise time SDA hold time SDA valid time After SCL F.E. After SCL F.E. After SCL F.E. After SCL R.E. Before Stop Condition After Start Condition Before Start Condition Before SCL R.E. Before SCL R.E.
tSCLhigho tSCLhigho tSCLhigho tSCLhigho tSCLhigho -tSDAro tSCLhigho -tSDAfo 300c -d (K x tCLK) -1e (K x tCLK) -1e 300
-
tSDAfo tSDAro tSDAho tSDAvo
(7 x tCLK) - tSCLfo (7 x tCLK) + tRD
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0.7VCC SDA 0.3VCC
0.7VCC 0.3VCC
tSDAr
tSDAf
0.7VCC SCL 0.3VCC
0.7VCC 0.3VCC
tSCLr
tSCLf
Note: In the timing tables the parameter name is added with an "o" for output signal timing and "i" for input signal timing. DS106
Figure 107. ACB Signals (SDA and SCL) Timing
Stop Condition
Start Condition
SDA
tDLCs
SCL
tCSTOs
tBUF
tCSTRh
Note: In the timing tables the parameter name is added with an "o" for output signal timing and "i" for input signal timing.
DS107
Figure 108. ACB Start and Stop Condition Timing
Start Condition
SDA
SCL
tCSTRs tDHCs
tCSTRh
Note: In the timing tables the parameter name is added with an "o" for output signal timing and "i" for input signal timing. DS108
Figure 109.
ACB Start Condition Timing
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SDA
tSDAsi SCL
tSCAvo tSDAh
tCSLlow
tSCLhigh
Note: In the timing tables the parameter name is added with an "o" for output signal timing and "i" for input signal timing. unless the parameter already includes the suffix. DS109
Figure 110.
ACB Data Timing
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28.12
MULTI-FUNCTION TIMER (MFT) TIMING
Table 80 Multi-Function Timer Input Signals
Symbol Figure tTAH tTAL tTBH tTBL 111 111 111 111
Description TA High Time TA Low Time TB High Time TB Low Time
Reference Rising Edge (RE) on CLK RE on CLK RE on CLK RE on CLK
Min (ns) TCLK + 5 TCLK + 5 TCLK + 5 TCLK + 5
Max (ns)
CLK tTAL /tTBL tTAL /tTBH
TA/TB
DS169
Figure 111. Multi-Function Timer Input Timing
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28.13
VERSATILE TIMING UNIT (VTU) TIMING
Table 81 Versatile Timing Unit Input Signals
Symbol tTIOH tTIOL
Figur e 111 111
Description TIOx Input High Time TIOx Input Low Time
Reference Rising Edge (RE) on CLK RE on CLK
Min (ns) 1.5 x TCLK + 5ns 1.5 x TCLK + 5ns
Max (ns)
CLK tTIOL tTIOH
TIOx
DS110
Figure 112. Versatile Timing Unit Input Timing
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28.14
EXTERNAL BUS TIMING
Table 82 External Bus Signals Reference External Bus Input Signals 113, 115, Input Setup Time 116, D[15:0] 117 113, 115, Output Hold Time 116, D[15:0] 117 Before Rising Edge (RE) on CLK Min (ns) Max (ns)
Symbol Figure
Description
t1
8
t2
After RE on CLK
0
External Bus Output Signals t3 113, Output Valid Time 114 D[15:0] 113, 114, Output Valid Time 115, A[22:0] 116, 117 113, 114, 115, 116, 117 Output Active/Inactive Time RD SEL[1:0] SELIO After RE on CLK 8
t4
After RE on CLK
8
t5
After RE on CLK
8
t6 t7 t8 t9 t10 t11
113, Output Active/Inactive Time 114 WR[1:0] 115 113 113 Minimum Inactive Time RD Output Float Time D[15:0] Minimum Delay Time
After RE on CLK At 2.0V After RE on CLK From RD Trailing Edge (TE) to D[15:0] driven From RD TE to SELn Leading Edge (LE) From SELx TE to SELy LE Tclk - 4 0 0 Tclk - 4
0.5 Tclk + 8
8
113, Minimum Delay Time 114 114 113, 114, 115, 116, 117 Minimum Delay Time Output Hold Time A[22:0] D[15:0] RD SEL[2:0] SELIO
t12
After RE on CLK
0
t13
113, Output Hold Time 114 WR[1:0]
After RE on CLK
0.5 Tclk - 3
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Normal Read Bus State CLK t4 A[21:0] A22 ('13 only) T1 T2 T1
Early Write T2 T3 T1
Normal Read T2
t4, t12
SELx t5, t12 SELy (y x) t2 t3 D[15:0] t5, t12 RD t5, t12 t9 t6, t13 t6, t13 WR[1:0] In Out t8, t12 In t1 t5, t12 t5, t12 t5, t12
DS124
Figure 113.
Early Write Between Normal Read Cycles (No Wait States)
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Normal Read
Late Write
Normal Read
Bus State CLK
T1
T2
T1
T2
T1
T2
t4, t12 A[21:0] A22 ('13 only) t5, t12 SELx (y x) t11 SELy (y x) t5, t12 t3 D[15:0] In Out
t4, t12
t5, t12
t5, t12
t8, t12 In
t10 RD t9 t6, t13 WR[1:0] t6, t13
t5, t12 t5, t12
DS125
Figure 114.
Late Write Between Normal Read Cycles (No Wait States)
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Normal Read Bus State CLK t4, t12 t4, t12 T1 T2 T2B T1
Normal Read T2 T2B
t4 A[21:0] A22 ('13 only)
t5, t12 SELx (y x)
t5, t12
t5, t12 SELy (y x)
t5, t12
t2 t1 t2 t1 In In In In
D[15:0]
t5, t12 RD t5, t12 t7
WR[1:0]
DS126
Figure 115. Consecutive Normal Read Cycles (Burst, No Wait States)
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Bus State CLK
T1
TW
T2
TH
t4, t12 t4 A21:0 A22 ('13 only) t5, t12 t5, t12 SELn, SELIO t2 t1 D[15:0] t5, t12 t5, t12 RD
WR[1:0]
DS127
Figure 116.
Normal Read Cycle (Wait Cycle Followed by Hold Cycle)
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Fast Read Bus State CLK t4, t12 Tidle T1-2 T1
Early Write T2 T3
Fast Read T1-2 T1
t4 A[21:0] A22 ('13 only)
SELx (y x)
t5, t12 t5, t12
SELy (y x)
t1 t2
D[15:0]
In
Out
In
RD t5, t12 t5, t12 WR[1:0]
DS128
Figure 117. Early Write Between Fast Read Cycles
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29.0 Pin Assignments
29.1 LQFP-128 PACKAGE
For 128-pin devices, Figure 118 provides a pinout diagram, and Table 83 provides the pin assignments. The physical dimensions are provided in Section 31.0.
TDI TMS RESET ADC7/ADCIN ADC6 ADC5/MUXOUT1 ADC4/MUXOUT0 ADC3/TSYADC2/TSXADC1/TSY+ ADC0/TSX+ VREF ADGND ADVCC PE3/CTS PE0/RXD0 PE2/RTS GND VCC PE1/TXD0 SDA SCL IOVCC IOGND VCC GND IOGND IOVCC IOVCC PG5 PG4 PG3 PG1 PG0 NC IOGND PJ6/WUI24 PJ5/WUI23 65 TCK PJ7/ASYNC/WUI9 PH0/RXD1/WUI11 TDO IOVCC RDY PF3/MWCS/TIO4 IOGND PF0/MSK/TIO1 GND VCC PF1/MDIDO/TIO2 IOVCC PF2/MDODI/TIO3 IOGND PG2/SRCLK IOGND PE5/SRFS/NMI IOVCC PF4/SCK/TIO5 PF5/SFS/TIO6 IOGND PF6/STD/TIO7 PF7/SRD/TIO8 IOVCC PJ0 103 PJ4/WUI22 IOVCC PE7/CAN1TX PE6/CAN1RX IOGND PH7/CAN0TX IOVCC PH6/CAN0RX/WUI17 GND VCC PH5/TXD3/WUI16 IOGND PH4/RXD3/WUI15 IOVCC PH3/TXD2/WUI14 IOGND PH2/RXD2/WUI13 IOVCC PH1/TXD1/WUI12 IOGND IOVCC IOGND IOVCC PG7/TA PE4/CKX/TB PJ3/WUI21
CP3CN23 (LQFP-128)
39 1 PJ1/WUI19 PC7 PC6 IOGND PC5 PC4 IOVCC PC3 PC2 IOGND PC1 PC0 IOVCC PB7 PB6 PB5 IOGND PB4 PB3 PB2 IOVCC PB1 PB0 GND VCC X1CKO X1CKI/BBCLK AGND AVCC X2CKI X2CKO VCC GND ENV2/SLOWCLK ENV1/CPUCLK ENV0/PLLCLK PG6/WUI10 PJ2/WUI20
DS308
Figure 118.
CP3CN23 in the LQFP-128 Package (Top View)
Table 83 Pin Assignments for LQFP-128 Package Pin Name GND VCC IOGND Alternate Function(s) Pin Numbers 24, 33, 56, 77, 85, 112 25, 32, 55, 78, 84, 113 4, 10, 17, 43, 45, 49, 53, 60, 67, 76, 79, 110, 117, 119, 124 7, 13, 21, 42, 44, 47, 51, 58, 63, 74, 75, 80, 107, 115, 121, 127 26 BBCLK 27 28 Type PWR PWR PWR
IOVCC X1CKO X1CKI AGND
PWR O I PWR
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Table 83 Pin Assignments for LQFP-128 Package Pin Name AVCC ADGND ADVCC X2CKI X2CKO ENV2 ENV1 ENV0 RESET TMS TDI TCK TDO RDY SCL SDA ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 ADC6 ADC7 VREFP PB0 PB1 PB2 PB3 PB4 PB5 PB6 PB7 PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7 PE0 PE1 www.national.com D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 RXD0 TXD0 238 ADCIN TSX+ TSY+ TSXTSYMUXOUT0 MUXOUT1 SLOWCLK CPUCLK PLLCLK Alternate Function(s) Pin Numbers 29 90 89 30 31 34 35 36 100 101 102 103 106 108 81 82 92 93 94 95 96 97 98 99 91 23 22 20 19 18 16 15 14 12 11 9 8 6 5 3 2 87 83 Type PWR PWR PWR I O I/O I/O I/O I I I I O O I/O I/O I/O/HIZ 20mA+ I/O/HIZ 20mA+ I/O/HIZ 20mA+ I/O/HIZ 20mA+ I/O I/O I I I GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO
CP3CN23
Table 83 Pin Assignments for LQFP-128 Package Pin Name PE2 PE3 PE4 PE5 PE6 PE7 PF0 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PG0 PG1 PG2 PG3 PG4 PG5 PG6 PG7 PH0 PH1 PH2 PH3 PH4 PH5 PH6 PH7 PJ0 PJ1 PJ2 PJ3 PJ4 PJ5 PJ6 PJ7 WUI10 TA RXD1/WUI11 TXD1/WUI12 RXD2/WUI13 TXD2/WUI14 RXD3/WUI15 TXD3/WUI16 CAN0RX/WUI17 CAN0TX WUI18 WUI19 WUI20 WUI21 WUI22 WUI23 WUI24 ASYNC/WUI9 SRCLK Alternate Function(s) RTS CTS CKX/TB SRFS/NMI CAN1RX CAN1TX MSK/TIO1 MDIDO/TIO2 MDODI/TIO3 MWCS/TIO4 SCK/TIO5 SFS/TIO6 STD/TIO7 SRD/TIO8 Pin Numbers 86 88 40 120 61 62 111 114 116 109 122 123 125 126 69 70 118 71 72 73 37 41 105 46 48 50 52 54 57 59 128 1 38 39 64 65 66 104 Type GPIO GPIO GPIO GPIO I/O I/O GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO
Note 1: The ENV0, ENV1, ENV2, RESET, TCK, TDI, and TMS pins each have a weak pull-up to keep the input from floating. Note 2: These functions are always enabled, due to the direct low-impedance path to these pins.
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29.2
LQFP-144 PACKAGE
For 144-pin devices, Figure 119 provides a pinout diagram, and Table 84 provides the pin assignments. The physical dimensions are provided in Section 31.0.
TDI TMS RESET ADC7/ADCIN ADC6 ADC5/MUXOUT1 ADC4/MUXOUT0 ADC3/TSYADC2/TSXADC1/TSY+ ADC0/TSX+ VREF ADGND ADVCC PE3/CTS PE0/RXD0 PE2/RTS GND VCC PE1/TXD0 SDA SCL VCC GND IOGND SELIO SEL2 SEL1 IOVCC SEL0 PG5 PG4 PG3 PG1 PG0 NC TCK PJ7/ASYNC/WUI9 PH0/RXD1/WUI11 TDO RDY A0 PF3/MWCS/TIO4 A1 IOGND A2 A3 PF0/MSK/TIO1 GND VCC PF1/MDIDO/TIO2 A4 A5 IOVCC PF2/MDODI/TIO3 A6 A7 IOGND A8 A9 PG2/SRCLK PE5/SRFS/NMI PF4/SCK/TIO5 PF5/SFS/TIO6 PF6/STD/TIO7 PF7/SRD/TIO8 A10 IOVCC A11 A12 A13 PJ0/WUI18 73 109 IOVCC PE7/CAN1TX PE6/CAN1RX WR1 WR0 IOGND RD PH7/CANTX IOVCC A22 A21 A20 PH6/CANRX/WUI17 GND VCC PH5/TXD3/WUI16 IOGND A19 A18 PH4/RXD3/WUI15 IOVCC PH3/TXD2/WUI14 IOGND PH2/RXD2/WUI13 IOVCC PH1/TXD1/WUI12 IOGND A17 IOVCC IOGND A16 IOVCC A15 A14 PG7/TA PE4/CKX/TB
CP3CN23 (LQFP-144)
37 1
PC7 PC6 IOGND PC5 PC4 IOVCC PC3 PC2 IOGND PC1 PC0 IOVCC PB7 PB6 PB5 IOGND PB4 PB3 PB2 IOVCC PB1 PB0 GND VCC X1CKO X1CKI/BBCLKO AGND AVCC X2CKI X2CKO VCC GND ENV2/SLOWCLK ENV1/CPUCLK ENV0/PLLCLK PG6/WUI10
DS309
Figure 119.
CP3CN23 in the LQFP-144 Package (Top View)
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CP3CN23
Table 84 Pin Assignments for LQFP-144 Package Pin Name GND VCC IOGND IOVCC AGND AVCC ADGND ADVCC X1CKI X1CKO X2CKI X2CKO ENV2 ENV1 ENV0 RESET TMS TDI TCK TDO RDY SCL SDA ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 ADC6 ADC7 VREFP PB0 PB1 PB2 PB3 PB4 PB5 PB6 PB7 PC0 D0 D1 D2 D3 D4 D5 D6 D7 D8 ADCIN TSX+ TSY+ TSXTSYMUXOUT0 MUXOUT1 SLOWCLK CPUCLK PLLCLK BBCLK Alternate Function(s) Pin Number 23, 32, 59, 85, 91, 121 24, 31, 58, 86, 90, 122 3, 9, 16, 43, 46, 50, 56, 67, 84, 117, 130 6, 12, 20, 41, 44, 48, 52, 64, 72, 80, 126, 140 27 28 96 95 26 25 29 30 33 34 35 106 107 108 109 112 113 87 88 98 99 100 101 102 103 104 105 97 22 21 19 18 17 15 14 13 11 Type PWR PWR PWR PWR PWR PWR PWR PWR I O I O I/O I/O I/O I I I I O O I/O I/O I/O/HIZ 20mA+ I/O/HIZ 20mA+ I/O/HIZ 20mA+ I/O/HIZ 20mA+ I/O I/O I I I GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO
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Pin Name PC1 PC2 PC3 PC4 PC5 PC6 PC7 PE0 PE1 PE2 PE3 PE4 PE5 PE6 PE7 PF0 PF1 PF2 PF3 PF4 PF5 PF6 PF7 PG0 PG1 PG2 PG3 PG4 PG5 PG6 PG7 PH0 PH1 PH2 PH3 PH4 PH5 PH6 PH7 PJ0 PJ7 A22 A21 A20 www.national.com
Alternate Function(s) D9 D10 D11 D12 D13 D14 D15 RXD0 TXD0 RTS CTS CKX/TB SRFS/NMI CAN1RX CAN1TX MSK/TIO1 MDIDO/TIO2 MDODI/TIO3 MWCS/TIO4 SCK/TIO5 SFS/TIO6 STD/TIO7 SRD/TIO8
Pin Number 10 8 7 5 4 2 1 93 89 92 94 37 134 70 71 120 123 127 115 135 136 137 138 74 75
Type GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO O O O
SRCLK
133 76 77 78
WUI10 TA RXD1/WUI11 TXD1/WUI12 RXD2/WUI13 TXD2/WUI14 RXD3/WUI15 TXD3/WUI16 CAN0RX/WUI17 CAN0TX WUI18 ASYNC
36 38 111 47 49 51 53 57 60 65 144 110 63 62 61
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Pin Name A19 A18 A17 A16 A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 SEL0 SEL1 SEL2 SELIO RD WR0 WR1
Alternate Function(s)
Pin Number 55 54 45 42 40 39 143 142 141 139 132 131 129 128 125 124 119 118 116 114 79 81 82 83 66 68 69
Type O O O O O O O O O O O O O O O O O O O O O O O O O O O
Note 1: The ENV0, ENV1, ENV2, RESET, TCK, TDI, and TMS pins each have a weak pull-up to keep the input from floating. Note 2: These functions are always enabled, due to the direct low-impedance path to these pins.
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30.0 Revision History
Table 85 Revision History Date 10/7/03 Major Changes From Previous Version Original release. Defined valid range of SCDV field in Microwire/SPI module. Noted default PRSSC register value generates a Slow Clock frequency slightly higher than 32768 Hz. Clarified usage of CVSTAT register bits and fields in CVSD/PCM module. Added usage hint for avoiding ACCESS.bus module bus error. Added usage hint for avoiding CAN unexpected loopback condition. Changed NSID designations in the product selection guide. Added entry for CTIM register in CAN section register list. Changed CVSD Conversion section. Changed definition of the RESOLUTION field of the CVSD Control register (CVCTRL). Changed reset values for ADC registers. Added maximum I/O voltage in Absolute Maximum Ratings section. Added RESET Low minimum DC specification. Added Iccprog DC specification. Changed Vxl2 DC specification. Updated DC specifications for clock input low voltage, reset input high voltage, and halt current. Corrected NSIDs for no-lead solder parts. Moved revision history in front of physical dimensions. Changed back page disclaimers.
11/14/03
2/28/04
3/16/04 5/10/04 5/12/04
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31.0 Physical Dimensions (millimeters) unless otherwise noted
Figure 120.
LQFP-128 Package
Figure 121.
LQFP-144 Package
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CP3CN23 Connectivity Processor with Bluetooth and Dual CAN Interfaces
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2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
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