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P REL I MIN AR Y
LM3S317 Microcontroller
D A TA S H E E T
DS-LM3S31 7-02
Co pyrigh t (c) 200 7 Lumin ary Micro, In c.
Legal Disclaimers and Trademark Information
INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH LUMINARY MICRO PRODUCTS. NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. EXCEPT AS PROVIDED IN LUMINARY MICRO'S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, LUMINARY MICRO ASSUMES NO LIABILITY WHATSOEVER, AND LUMINARY MICRO DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY, RELATING TO SALE AND/OR USE OF LUMINARY MICRO'S PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LUMINARY MICRO'S PRODUCTS ARE NOT INTENDED FOR USE IN MEDICAL, LIFE SAVING, OR LIFE-SUSTAINING APPLICATIONS. Luminary Micro may make changes to specifications and product descriptions at any time, without notice. Contact your local Luminary Micro sales office or your distributor to obtain the latest specifications before placing your product order. Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined." Luminary Micro reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them. Copyright (c) 2007 Luminary Micro, Inc. All rights reserved. Stellaris is a registered trademark and the Luminary Micro logo is a trademark of Luminary Micro, Inc. or its subsidiaries in the United States and other countries. ARM and Thumb are registered trademarks, and Cortex is a trademark of ARM Limited. Other names and brands may be claimed as the property of others. Luminary Micro, Inc. 108 Wild Basin, Suite 350 Austin, TX 78746 Main: +1-512-279-8800 Fax: +1-512-279-8879 http://www.luminarymicro.com
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LM3S317 Data Sheet
Table of Contents
Legal Disclaimers and Trademark Information.............................................................................. 2 Revision History ............................................................................................................................. 16 About This Document..................................................................................................................... 17
Audience........................................................................................................................................................... 17 About This Manual............................................................................................................................................ 17 Related Documents .......................................................................................................................................... 17 Documentation Conventions............................................................................................................................. 17
1.
1.1 1.2 1.3 1.4 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5 1.4.6 1.4.7 1.4.8 1.5
Architectural Overview ....................................................................................................... 20
Product Features ................................................................................................................................. 20 Target Applications .............................................................................................................................. 24 High-Level Block Diagram ................................................................................................................... 25 Functional Overview ............................................................................................................................ 26 ARM CortexTM-M3 ............................................................................................................................... 26 Motor Control Peripherals .................................................................................................................... 26 Analog Peripherals .............................................................................................................................. 27 Serial Communications Peripherals..................................................................................................... 27 System Peripherals.............................................................................................................................. 28 Memory Peripherals............................................................................................................................. 29 Additional Features .............................................................................................................................. 29 Hardware Details ................................................................................................................................. 30 System Block Diagram ........................................................................................................................ 31
2.
2.1 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6
ARM Cortex-M3 Processor Core........................................................................................ 32
Block Diagram ..................................................................................................................................... 33 Functional Description ......................................................................................................................... 33 Serial Wire and JTAG Debug .............................................................................................................. 33 Embedded Trace Macrocell (ETM) ...................................................................................................... 34 Trace Port Interface Unit (TPIU) .......................................................................................................... 34 ROM Table .......................................................................................................................................... 34 Memory Protection Unit (MPU) ............................................................................................................ 34 Nested Vectored Interrupt Controller (NVIC) ....................................................................................... 34
3. 4. 5.
5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.3 5.4 5.4.1 5.4.2
Memory Map ........................................................................................................................ 40 Interrupts ............................................................................................................................. 42 JTAG Interface .................................................................................................................... 45
Block Diagram ..................................................................................................................................... 46 Functional Description ......................................................................................................................... 46 JTAG Interface Pins............................................................................................................................. 47 JTAG TAP Controller ........................................................................................................................... 48 Shift Registers ..................................................................................................................................... 49 Operational Considerations ................................................................................................................. 49 Initialization and Configuration............................................................................................................. 50 Register Descriptions........................................................................................................................... 51 Instruction Register (IR) ....................................................................................................................... 51 Data Registers ..................................................................................................................................... 53
6.
6.1 6.1.1
System Control.................................................................................................................... 55
Functional Description ......................................................................................................................... 55 Device Identification............................................................................................................................. 55
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Table of Contents
6.1.2 6.1.3 6.1.4 6.1.5 6.2 6.3 6.4
Reset Control ....................................................................................................................................... 55 Power Control ...................................................................................................................................... 58 Clock Control ....................................................................................................................................... 58 System Control .................................................................................................................................... 60 Initialization and Configuration............................................................................................................. 61 Register Map ....................................................................................................................................... 61 Register Descriptions........................................................................................................................... 62
7.
7.1 7.2 7.2.1 7.2.2 7.3 7.3.1 7.3.2 7.4 7.5
Internal Memory .................................................................................................................. 97
Block Diagram ..................................................................................................................................... 97 Functional Description ......................................................................................................................... 97 SRAM Memory .................................................................................................................................... 97 Flash Memory ...................................................................................................................................... 98 Initialization and Configuration........................................................................................................... 100 Changing Flash Protection Bits ......................................................................................................... 100 Flash Programming ........................................................................................................................... 101 Register Map ..................................................................................................................................... 101 Register Descriptions......................................................................................................................... 102
8.
8.1 8.2 8.2.1 8.2.2 8.2.3 8.2.4 8.2.5 8.2.6 8.3 8.4 8.5
General-Purpose Input/Outputs (GPIOs) ........................................................................ 114
Block Diagram ................................................................................................................................... 115 Functional Description ....................................................................................................................... 115 Data Register Operation .................................................................................................................... 116 Data Direction .................................................................................................................................... 117 Interrupt Operation............................................................................................................................. 117 Mode Control ..................................................................................................................................... 118 Pad Configuration .............................................................................................................................. 118 Identification....................................................................................................................................... 118 Initialization and Configuration........................................................................................................... 118 Register Map ..................................................................................................................................... 120 Register Descriptions......................................................................................................................... 121
9.
9.1 9.2 9.2.1 9.2.2 9.2.3 9.3 9.3.1 9.3.2 9.3.3 9.3.4 9.3.5 9.3.6 9.4 9.5
General-Purpose Timers .................................................................................................. 152
Block Diagram ................................................................................................................................... 153 Functional Description ....................................................................................................................... 153 GPTM Reset Conditions .................................................................................................................... 153 32-Bit Timer Operating Modes........................................................................................................... 153 16-Bit Timer Operating Modes........................................................................................................... 155 Initialization and Configuration........................................................................................................... 159 32-Bit One-Shot/Periodic Timer Mode ............................................................................................... 159 32-Bit Real-Time Clock (RTC) Mode ................................................................................................. 160 16-Bit One-Shot/Periodic Timer Mode ............................................................................................... 160 16-Bit Input Edge Count Mode .......................................................................................................... 160 16-Bit Input Edge Timing Mode ......................................................................................................... 161 16-Bit PWM Mode.............................................................................................................................. 161 Register Map ..................................................................................................................................... 162 Register Descriptions......................................................................................................................... 163
10.
10.1 10.2 10.3
Watchdog Timer ................................................................................................................ 184
Block Diagram ................................................................................................................................... 184 Functional Description ....................................................................................................................... 185 Initialization and Configuration........................................................................................................... 185
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LM3S317 Data Sheet
10.4 10.5
Register Map ..................................................................................................................................... 185 Register Descriptions......................................................................................................................... 186
11.
11.1 11.2 11.2.1 11.2.2 11.2.3 11.2.4 11.2.5 11.2.6 11.3 11.3.1 11.3.2 11.4 11.5
Analog-to-Digital Converter (ADC) .................................................................................. 207
Block Diagram ................................................................................................................................... 208 Functional Description ....................................................................................................................... 208 Sample Sequencers .......................................................................................................................... 208 Module Control .................................................................................................................................. 209 Hardware Sample Averaging Circuit.................................................................................................. 210 Analog-to-Digital Converter ............................................................................................................... 210 Test Modes ........................................................................................................................................ 210 Internal Temperature Sensor ............................................................................................................. 210 Initialization and Configuration........................................................................................................... 210 Module Initialization ........................................................................................................................... 211 Sample Sequencer Configuration ...................................................................................................... 211 Register Map ..................................................................................................................................... 211 Register Descriptions......................................................................................................................... 212
12.
12.1 12.2 12.2.1 12.2.2 12.2.3 12.2.4 12.2.5 12.2.6 12.3 12.4 12.5
Universal Asynchronous Receiver/Transmitter (UART)................................................ 237
Block Diagram ................................................................................................................................... 238 Functional Description ....................................................................................................................... 238 Transmit/Receive Logic ..................................................................................................................... 238 Baud-Rate Generation ....................................................................................................................... 239 Data Transmission ............................................................................................................................. 240 FIFO Operation .................................................................................................................................. 240 Interrupts............................................................................................................................................ 240 Loopback Operation .......................................................................................................................... 241 Initialization and Configuration........................................................................................................... 241 Register Map ..................................................................................................................................... 242 Register Descriptions......................................................................................................................... 243
13.
13.1 13.2 13.2.1 13.2.2 13.2.3 13.2.4 13.3 13.4 13.5
Synchronous Serial Interface (SSI) ................................................................................. 273
Block Diagram ................................................................................................................................... 273 Functional Description ....................................................................................................................... 274 Bit Rate Generation ........................................................................................................................... 274 FIFO Operation .................................................................................................................................. 274 Interrupts............................................................................................................................................ 274 Frame Formats .................................................................................................................................. 275 Initialization and Configuration........................................................................................................... 282 Register Map ..................................................................................................................................... 283 Register Descriptions......................................................................................................................... 284
14.
14.1 14.2 14.2.1 14.3 14.4 14.5
Analog Comparator........................................................................................................... 308
Block Diagram ................................................................................................................................... 308 Functional Description ....................................................................................................................... 308 Internal Reference Programming....................................................................................................... 309 Initialization and Configuration........................................................................................................... 310 Register Map ..................................................................................................................................... 311 Register Descriptions......................................................................................................................... 311
15.
15.1 15.2
Pulse Width Modulator (PWM) ......................................................................................... 319
Block Diagram ................................................................................................................................... 319 Functional Description ....................................................................................................................... 319
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Table of Contents
15.2.1 15.2.2 15.2.3 15.2.4 15.2.5 15.2.6 15.2.7 15.2.8 15.3 15.4 15.5
PWM Timer ........................................................................................................................................ 319 PWM Comparators ............................................................................................................................ 319 PWM Signal Generator ...................................................................................................................... 320 Dead-Band Generator ....................................................................................................................... 321 Interrupt Selector ............................................................................................................................... 321 Synchronization Methods .................................................................................................................. 321 Fault Conditions ................................................................................................................................. 322 Output Control Block.......................................................................................................................... 322 Initialization and Configuration........................................................................................................... 322 Register Map ..................................................................................................................................... 323 Register Descriptions......................................................................................................................... 324
16. 17. 18. 19.
19.1 19.1.1 19.1.2 19.1.3 19.1.4 19.1.5 19.2 19.2.1 19.2.2 19.2.3 19.2.4 19.2.5 19.2.6 19.2.7 19.2.8
Pin Diagram ....................................................................................................................... 348 Signal Tables ..................................................................................................................... 349 Operating Characteristics ................................................................................................ 359 Electrical Characteristics ................................................................................................. 360
DC Characteristics ............................................................................................................................. 360 Maximum Ratings .............................................................................................................................. 360 Recommended DC Operating Conditions ......................................................................................... 360 On-Chip Low Drop-Out (LDO) Regulator Characteristics .................................................................. 361 Power Specifications ......................................................................................................................... 362 Flash Memory Characteristics ........................................................................................................... 363 AC Characteristics ............................................................................................................................. 363 Load Conditions ................................................................................................................................. 363 Clocks ................................................................................................................................................ 363 Analog-to-Digital Converter ............................................................................................................... 364 Analog Comparator............................................................................................................................ 365 Synchronous Serial Interface (SSI) ................................................................................................... 365 JTAG and Boundary Scan ................................................................................................................. 367 General-Purpose I/O.......................................................................................................................... 369 Reset ................................................................................................................................................. 369
20.
21.1 21.1.1 21.1.2 21.2 21.2.1 21.2.2 21.2.3 21.3 21.3.1 21.3.2 21.3.3 21.3.4 21.3.5 21.3.6
Package Information......................................................................................................... 372
Interfaces ........................................................................................................................................... 373 UART ................................................................................................................................................. 373 SSI ..................................................................................................................................................... 373 Packet Handling................................................................................................................................. 373 Packet Format ................................................................................................................................... 374 Sending Packets ................................................................................................................................ 374 Receiving Packets ............................................................................................................................. 374 Commands ........................................................................................................................................ 374 COMMAND_PING (0x20) .................................................................................................................. 375 COMMAND_GET_STATUS (0x23) ................................................................................................... 375 COMMAND_DOWNLOAD (0x21)...................................................................................................... 375 COMMAND_SEND_DATA (0x24) ..................................................................................................... 375 COMMAND_RUN (0x22) ................................................................................................................... 376 COMMAND_RESET (0x25)............................................................................................................... 376
Appendix A. Serial Flash Loader ............................................................................................... 373
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LM3S317 Data Sheet
Ordering and Contact Information .............................................................................................. 378
Ordering Information....................................................................................................................................... 378 Development Kit ............................................................................................................................................. 378 Company Information ..................................................................................................................................... 378 Support Information ........................................................................................................................................ 379
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List of Figures
List of Figures
Figure 1-1. Figure 1-2. Figure 2-1. Figure 2-2. Figure 5-1. Figure 5-2. Figure 5-3. Figure 5-4. Figure 5-5. Figure 6-1. Figure 6-2. Figure 7-1. Figure 8-1. Figure 8-2. Figure 8-3. Figure 8-4. Figure 9-1. Figure 9-2. Figure 9-3. Figure 9-4. Figure 10-1. Figure 11-1. Figure 11-2. Figure 12-1. Figure 12-2. Figure 13-1. Figure 13-2. Figure 13-3. Figure 13-4. Figure 13-5. Figure 13-6. Figure 13-7. Figure 13-8. Figure 13-9. Figure 13-10. Figure 13-11. Figure 13-12. Figure 14-1. Figure 14-2. Figure 14-3. Figure 15-1. Figure 15-2. Figure 15-3. Figure 15-4. Figure 15-5. Figure 16-1. Stellaris(R) High-Level Block Diagram ...................................................................................... 25 LM3S317 Controller System-Level Block Diagram ................................................................... 31 CPU Block Diagram .................................................................................................................. 33 TPIU Block Diagram .................................................................................................................. 34 JTAG Module Block Diagram .................................................................................................... 46 Test Access Port State Machine ............................................................................................... 49 IDCODE Register Format.......................................................................................................... 53 BYPASS Register Format ......................................................................................................... 53 Boundary Scan Register Format ............................................................................................... 54 External Circuitry to Extend Reset............................................................................................. 56 Main Clock Tree ........................................................................................................................ 59 Flash Block Diagram ................................................................................................................. 97 GPIO Module Block Diagram .................................................................................................. 115 GPIO Port Block Diagram........................................................................................................ 116 GPIODATA Write Example...................................................................................................... 117 GPIODATA Read Example ..................................................................................................... 117 GPTM Module Block Diagram ................................................................................................. 153 16-Bit Input Edge Count Mode Example ................................................................................. 157 16-Bit Input Edge Time Mode Example................................................................................... 158 16-Bit PWM Mode Example .................................................................................................... 159 WDT Module Block Diagram ................................................................................................... 184 ADC Module Block Diagram.................................................................................................... 208 Internal Temperature Sensor Characteristic............................................................................ 210 UART Module Block Diagram.................................................................................................. 238 UART Character Frame........................................................................................................... 239 SSI Module Block Diagram...................................................................................................... 273 TI Synchronous Serial Frame Format (Single Transfer).......................................................... 275 TI Synchronous Serial Frame Format (Continuous Transfer) ................................................. 276 Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 .......................................... 277 Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 .................................. 277 Freescale SPI Frame Format with SPO=0 and SPH=1........................................................... 278 Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0............................... 278 Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0....................... 279 Freescale SPI Frame Format with SPO=1 and SPH=1........................................................... 279 MICROWIRE Frame Format (Single Frame)........................................................................... 280 MICROWIRE Frame Format (Continuous Transfer) ............................................................... 281 MICROWIRE Frame Format, SSIFss Input Setup and Hold Requirements............................ 282 Analog Comparator Module Block Diagram ............................................................................ 308 Structure of Comparator Unit................................................................................................... 309 Comparator Internal Reference Structure ............................................................................... 310 PWM Module Block Diagram................................................................................................... 319 PWM Count-Down Mode......................................................................................................... 320 PWM Count-Up/Down Mode ................................................................................................... 320 PWM Generation Example In Count-Up/Down Mode ............................................................. 321 PWM Dead-Band Generator ................................................................................................... 321 Pin Connection Diagram ....................................................................................................... 348
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LM3S317 Data Sheet
Figure 19-1. Figure 19-2. Figure 19-3. Figure 19-4. Figure 19-5. Figure 19-6. Figure 19-7. Figure 19-8. Figure 19-9. Figure 19-10. Figure 19-11. Figure 19-12. Figure 19-13. Figure 20-1.
Load Conditions....................................................................................................................... 363 SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement ................ 366 SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer................................. 366 SSI Timing for SPI Frame Format (FRF=00), with SPH=1...................................................... 366 JTAG Test Clock Input Timing................................................................................................. 368 JTAG Test Access Port (TAP) Timing ..................................................................................... 368 JTAG TRST Timing ................................................................................................................. 368 External Reset Timing (RST)................................................................................................... 370 Power-On Reset Timing .......................................................................................................... 370 Brown-Out Reset Timing ......................................................................................................... 370 Software Reset Timing ............................................................................................................ 370 Watchdog Reset Timing .......................................................................................................... 371 LDO Reset Timing ................................................................................................................... 371 48-Pin LQFP Package............................................................................................................. 372
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List of Tables
List of Tables
Table 0-1. Table 3-1. Table 4-1. Table 4-2. Table 5-1. Table 5-2. Table 6-1. Table 6-2. Table 6-3. Table 6-4. Table 7-1. Table 7-2. Table 8-1. Table 8-2. Table 8-3. Table 9-1. Table 9-2. Table 10-1. Table 11-1. Table 11-2. Table 12-1. Table 13-1. Table 14-1. Table 14-2. Table 14-3. Table 15-1. Table 15-2. Table 17-1. Table 17-2. Table 17-3. Table 17-4. Table 18-1. Table 18-2. Table 19-1. Table 19-2. Table 19-3. Table 19-4. Table 19-5. Table 19-6. Table 19-7. Table 19-8. Table 19-9. Table 19-10. Table 19-11. Table 19-12. Table 19-13. Table 19-14. Documentation Conventions ..................................................................................................... 17 Memory Map.............................................................................................................................. 40 Exception Types ........................................................................................................................ 42 Interrupts ................................................................................................................................... 43 JTAG Port Pins Reset State ...................................................................................................... 47 JTAG Instruction Register Commands ...................................................................................... 51 System Control Register Map.................................................................................................... 61 VADJ to VOUT .......................................................................................................................... 74 PLL Mode Control...................................................................................................................... 86 Default Crystal Field Values and PLL Programming ................................................................. 87 Flash Protection Policy Combinations ....................................................................................... 99 Flash Register Map ................................................................................................................. 102 GPIO Pad Configuration Examples ........................................................................................ 119 GPIO Interrupt Configuration Example ................................................................................... 119 GPIO Register Map ................................................................................................................. 120 16-Bit Timer with Prescaler Configurations ............................................................................. 156 GPTM Register Map................................................................................................................ 162 WDT Register Map .................................................................................................................. 185 Samples and FIFO Depth of Sequencers................................................................................ 208 ADC Register Map................................................................................................................... 211 UART Register Map ................................................................................................................ 242 SSI Register Map .................................................................................................................... 283 Comparator 0 Operating Modes .............................................................................................. 309 Internal Reference Voltage and ACREFCTL Field Values ...................................................... 310 Analog Comparator Register Map ........................................................................................... 311 PWM Register Map ................................................................................................................. 323 PWM Generator Action Encodings.......................................................................................... 343 Signals by Pin Number ............................................................................................................ 349 Signals by Signal Name .......................................................................................................... 352 Signals by Function, Except for GPIO ..................................................................................... 354 GPIO Pins and Alternate Functions......................................................................................... 357 Temperature Characteristics ................................................................................................... 359 Thermal Characteristics........................................................................................................... 359 Maximum Ratings.................................................................................................................... 360 Recommended DC Operating Conditions ............................................................................... 360 LDO Regulator Characteristics................................................................................................ 361 Power Specifications ............................................................................................................... 362 Flash Memory Characteristics ................................................................................................. 363 Phase Locked Loop (PLL) Characteristics .............................................................................. 363 Clock Characteristics............................................................................................................... 364 ADC Characteristics ................................................................................................................ 364 Analog Comparator Characteristics......................................................................................... 365 Analog Comparator Voltage Reference Characteristics.......................................................... 365 SSI Characteristics .................................................................................................................. 365 JTAG Characteristics............................................................................................................... 367 GPIO Characteristics............................................................................................................... 369 Reset Characteristics .............................................................................................................. 369
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LM3S317 Data Sheet
List of Registers
ARM Cortex-M3 Processor Core ................................................................................................... 32
Register 1: Register 2: Register 3: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: SysTick Control and Status Register......................................................................................... 37 SysTick Reload Value Register ................................................................................................. 38 SysTick Current Value Register ................................................................................................ 39 Device Identification 0 (DID0), offset 0x000 .............................................................................. 63 Device Identification 1 (DID1), offset 0x004 .............................................................................. 64 Device Capabilities 0 (DC0), offset 0x008................................................................................. 66 Device Capabilities 1 (DC1), offset 0x010................................................................................. 67 Device Capabilities 2 (DC2), offset 0x014................................................................................. 69 Device Capabilities 3 (DC3), offset 0x018................................................................................. 70 Device Capabilities 4 (DC4), offset 0x01C ................................................................................ 72 Power-On and Brown-Out Reset Control (PBORCTL), offset 0x030 ........................................ 73 LDO Power Control (LDOPCTL), offset 0x034.......................................................................... 74 Software Reset Control 0 (SRCR0), offset 0x040 ..................................................................... 75 Software Reset Control 1 (SRCR1), offset 0x044 ..................................................................... 76 Software Reset Control 2 (SRCR2), offset 0x048 ..................................................................... 77 Raw Interrupt Status (RIS), offset 0x050................................................................................... 78 Interrupt Mask Control (IMC), offset 0x054 ............................................................................... 79 Masked Interrupt Status and Clear (MISC), offset 0x058.......................................................... 81 Reset Cause (RESC), offset 0x05C .......................................................................................... 82 Run-Mode Clock Configuration (RCC), offset 0x060................................................................. 83 XTAL to PLL Translation (PLLCFG), offset 0x064 .................................................................... 88 Run-Mode Clock Gating Control 0 (RCGC0), offset 0x100 ....................................................... 89 Sleep-Mode Clock Gating Control 0 (SCGC0), offset 0x110..................................................... 89 Deep-Sleep-Mode Clock Gating Control 0 (DCGC0), offset 0x120........................................... 89 Run-Mode Clock Gating Control 1 (RCGC1), offset 0x104 ....................................................... 91 Sleep-Mode Clock Gating Control 1 (SCGC1), offset 0x114..................................................... 91 Deep-Sleep-Mode Clock Gating Control 1 (DCGC1), offset 0x124........................................... 91 Run-Mode Clock Gating Control 2 (RCGC2), offset 0x108 ....................................................... 93 Sleep-Mode Clock Gating Control 2 (SCGC2), offset 0x118..................................................... 93 Deep-Sleep-Mode Clock Gating Control 2 (DCGC2), offset 0x128........................................... 93 Deep-Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 .............................................. 94 Clock Verification Clear (CLKVCLR), offset 0x150.................................................................... 95 Allow Unregulated LDO to Reset the Part (LDOARST), offset 0x160 ....................................... 96 Flash Memory Protection Read Enable (FMPRE), offset 0x130 ............................................. 103 Flash Memory Protection Program Enable (FMPPE), offset 0x134 ........................................ 104 USec Reload (USECRL), offset 0x140.................................................................................... 105 Flash Memory Address (FMA), offset 0x000 ........................................................................... 106 Flash Memory Data (FMD), offset 0x004 ................................................................................ 108 Flash Memory Control (FMC), offset 0x008 ............................................................................ 109 Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C ................................................. 111 Flash Controller Interrupt Mask (FCIM), offset 0x010 ............................................................. 112 Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014......................... 113
System Control ............................................................................................................................... 55
Internal Memory .............................................................................................................................. 97
May 4, 2007 Preliminary
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List of Registers
General-Purpose Input/Outputs (GPIOs) .................................................................................... 114
Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: GPIO Data (GPIODATA), offset 0x000 ................................................................................... 122 GPIO Direction (GPIODIR), offset 0x400 ................................................................................ 123 GPIO Interrupt Sense (GPIOIS), offset 0x404......................................................................... 124 GPIO Interrupt Both Edges (GPIOIBE), offset 0x408.............................................................. 125 GPIO Interrupt Event (GPIOIEV), offset 0x40C....................................................................... 126 GPIO Interrupt Mask (GPIOIM), offset 0x410.......................................................................... 127 GPIO Raw Interrupt Status (GPIORIS), offset 0x414.............................................................. 128 GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 ........................................................ 129 GPIO Interrupt Clear (GPIOICR), offset 0x41C....................................................................... 130 GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 ................................................. 131 GPIO 2-mA Drive Select (GPIODR2R), offset 0x500.............................................................. 132 GPIO 4-mA Drive Select (GPIODR4R), offset 0x504.............................................................. 133 GPIO 8-mA Drive Select (GPIODR8R), offset 0x508.............................................................. 134 GPIO Open Drain Select (GPIOODR), offset 0x50C............................................................... 135 GPIO Pull-Up Select (GPIOPUR), offset 0x510 ...................................................................... 136 GPIO Pull-Down Select (GPIOPDR), offset 0x514.................................................................. 137 GPIO Slew Rate Control Select (GPIOSLR), offset 0x518...................................................... 138 GPIO Digital Input Enable (GPIODEN), offset 0x51C ............................................................. 139 GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 ........................................... 140 GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 ........................................... 141 GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 ........................................... 142 GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC........................................... 143 GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 ........................................... 144 GPIO Peripheral Identification 1(GPIOPeriphID1), offset 0xFE4 ............................................ 145 GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 ........................................... 146 GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC........................................... 147 GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 .............................................. 148 GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 .............................................. 149 GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 .............................................. 150 GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC.............................................. 151 GPTM Configuration (GPTMCFG), offset 0x000..................................................................... 164 GPTM TimerA Mode (GPTMTAMR), offset 0x004 .................................................................. 165 GPTM TimerB Mode (GPTMTBMR), offset 0x008 .................................................................. 166 GPTM Control (GPTMCTL), offset 0x00C............................................................................... 167 GPTM Interrupt Mask (GPTMIMR), offset 0x018 .................................................................... 169 GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C .......................................................... 171 GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 ..................................................... 172 GPTM Interrupt Clear (GPTMICR), offset 0x024..................................................................... 173 GPTM TimerA Interval Load (GPTMTAILR), offset 0x028 ...................................................... 174 GPTM TimerB Interval Load (GPTMTBILR), offset 0x02C...................................................... 175 GPTM TimerA Match (GPTMTAMATCHR), offset 0x030 ....................................................... 176 GPTM TimerB Match (GPTMTBMATCHR), offset 0x034 ....................................................... 177 GPTM TimerA Prescale (GPTMTAPR), offset 0x038.............................................................. 178 GPTM TimerB Prescale (GPTMTBPR), offset 0x03C ............................................................. 179 GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040................................................ 180 GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044................................................ 181
General-Purpose Timers .............................................................................................................. 152
12 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 17: Register 18: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24:
GPTM TimerA (GPTMTAR), offset 0x048 ............................................................................... 182 GPTM TimerB (GPTMTBR), offset 0x04C .............................................................................. 183 Watchdog Load (WDTLOAD), offset 0x000 ............................................................................ 187 Watchdog Value (WDTVALUE), offset 0x004 ......................................................................... 188 Watchdog Control (WDTCTL), offset 0x008............................................................................ 189 Watchdog Interrupt Clear (WDTICR), offset 0x00C ................................................................ 190 Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 ....................................................... 191 Watchdog Masked Interrupt Status (WDTMIS), offset 0x014.................................................. 192 Watchdog Lock (WDTLOCK), offset 0xC00 ............................................................................ 193 Watchdog Test (WDTTEST), offset 0x418 .............................................................................. 194 Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0..................................... 195 Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4..................................... 196 Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8..................................... 197 Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC .................................... 198 Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 ..................................... 199 Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 ..................................... 200 Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 ..................................... 201 Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC .................................... 202 Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0........................................ 203 Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4........................................ 204 Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8........................................ 205 Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC ...................................... 206 ADC Active Sample Sequencer (ADCACTSS), offset 0x000 .................................................. 213 ADC Raw Interrupt Status (ADCRIS), offset 0x004................................................................. 214 ADC Interrupt Mask (ADCIM), offset 0x008 ............................................................................ 215 ADC Interrupt Status and Clear (ADCISC), offset 0x00C........................................................ 216 ADC Overflow Status (ADCOSTAT), offset 0x010 .................................................................. 217 ADC Event Multiplexer Select (ADCEMUX), offset 0x014 ...................................................... 218 ADC Underflow Status (ADCUSTAT), offset 0x018 ................................................................ 219 ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020.................................................. 220 ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 ..................................... 221 ADC Sample Averaging Control (ADCSAC), offset 0x030 ...................................................... 222 ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040.................. 223 ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044............................................. 225 ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048.................................... 227 ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C................................ 228 ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060.................. 229 ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064............................................. 230 ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068.................................... 230 ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C................................ 230 ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080.................. 231 ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084............................................. 232 ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088.................................... 232 ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C................................ 232 ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 ................. 233 ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 ............................................ 234
Watchdog Timer............................................................................................................................ 184
Analog-to-Digital Converter (ADC).............................................................................................. 207
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List of Registers
Register 25: Register 26: Register 27: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19:
ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 ................................... 234 ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC ............................... 234 ADC Test Mode Loopback (ADCTMLB), offset 0x100 ............................................................ 235 UART Data (UARTDR), offset 0x000 ...................................................................................... 244 UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 .............................. 246 UART Flag (UARTFR), offset 0x018 ....................................................................................... 248 UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 ................................................. 250 UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 ........................................... 251 UART Line Control (UARTLCRH), offset 0x02C ..................................................................... 252 UART Control (UARTCTL), offset 0x030................................................................................. 254 UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 ................................................ 255 UART Interrupt Mask (UARTIM), offset 0x038 ........................................................................ 256 UART Raw Interrupt Status (UARTRIS), offset 0x03C............................................................ 258 UART Masked Interrupt Status (UARTMIS), offset 0x040 ...................................................... 259 UART Interrupt Clear (UARTICR), offset 0x044...................................................................... 260 UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0.......................................... 261 UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4.......................................... 262 UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8.......................................... 263 UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC ......................................... 264 UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0.......................................... 265 UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4.......................................... 266 UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8.......................................... 267 UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC ......................................... 268 UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0............................................. 269 UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4............................................. 270 UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8............................................. 271 UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC ............................................ 272 SSI Control 0 (SSICR0), offset 0x000 ..................................................................................... 285 SSI Control 1 (SSICR1), offset 0x004 ..................................................................................... 287 SSI Data (SSIDR), offset 0x008 .............................................................................................. 289 SSI Status (SSISR), offset 0x00C ........................................................................................... 290 SSI Clock Prescale (SSICPSR), offset 0x010 ......................................................................... 291 SSI Interrupt Mask (SSIIM), offset 0x014 ................................................................................ 292 SSI Raw Interrupt Status (SSIRIS), offset 0x018 .................................................................... 293 SSI Masked Interrupt Status (SSIMIS), offset 0x01C.............................................................. 294 SSI Interrupt Clear (SSIICR), offset 0x020.............................................................................. 295 SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0.................................................. 296 SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4.................................................. 297 SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8.................................................. 298 SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC ................................................. 299 SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0.................................................. 300 SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4.................................................. 301 SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8.................................................. 302 SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC ................................................. 303 SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0..................................................... 304 SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4..................................................... 305
Universal Asynchronous Receiver/Transmitter (UART) ........................................................... 237
Synchronous Serial Interface (SSI) ............................................................................................. 273
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LM3S317 Data Sheet
Register 20: Register 21: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22:
SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8..................................................... 306 SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC .................................................... 307 Analog Comparator Masked Interrupt Status (ACMIS), offset 0x00........................................ 312 Analog Comparator Raw Interrupt Status (ACRIS), offset 0x04.............................................. 313 Analog Comparator Interrupt Enable (ACINTEN), offset 0x08 ................................................ 314 Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x10 ............................ 315 Analog Comparator Status 0 (ACSTAT0), offset 0x20 ............................................................ 316 Analog Comparator Control 0 (ACCTL0), offset 0x24 ............................................................. 317 PWM Master Control (PWMCTL), offset 0x000....................................................................... 325 PWM Time Base Sync (PWMSYNC), offset 0x004................................................................. 326 PWM Output Enable (PWMENABLE), offset 0x008................................................................ 327 PWM Output Inversion (PWMINVERT), offset 0x00C............................................................. 328 PWM Output Fault (PWMFAULT), offset 0x010...................................................................... 329 PWM Interrupt Enable (PWMINTEN), offset 0x014................................................................. 330 PWM Raw Interrupt Status (PWMRIS), offset 0x018 .............................................................. 331 PWM Interrupt Status and Clear (PWMISC), offset 0x01C ..................................................... 332 PWM Status (PWMSTATUS), offset 0x020............................................................................. 333 PWM0 Control (PWM0CTL), offset 0x040............................................................................... 334 PWM0 Interrupt Enable (PWM0INTEN), offset 0x044............................................................. 335 PWM0 Raw Interrupt Status (PWM0RIS), offset 0x048 .......................................................... 336 PWM0 Interrupt Status and Clear (PWM0ISC), offset 0x04C ................................................. 337 PWM0 Load (PWM0LOAD), offset 0x050 ............................................................................... 338 PWM0 Counter (PWM0COUNT), offset 0x054 ....................................................................... 339 PWM0 Compare A (PWM0CMPA), offset 0x058 .................................................................... 340 PWM0 Compare B (PWM0CMPB), offset 0x05C.................................................................... 341 PWM0 Generator A Control (PWM0GENA), offset 0x060....................................................... 342 PWM0 Generator B Control (PWM0GENB), offset 0x064....................................................... 344 PWM0 Dead-Band Control (PWM0DBCTL), offset 0x068 ...................................................... 345 PWM0 Dead-Band Rising-Edge Delay (PWM0DBRISE), offset 0x06C .................................. 346 PWM0 Dead-Band Falling-Edge-Delay (PWM0DBFALL), offset 0x070.................................. 347
Analog Comparator ...................................................................................................................... 308
Pulse Width Modulator (PWM)..................................................................................................... 319
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Revision History
Revision History
This table provides a summary of the document revisions.
Date February 2007 April 2007 Revision 00 01 Description Initial release of LM3S317, LM3S617, LM3S618, LM3S817 and LM3S818 data sheet to customers. Second release of LM3S317, LM3S618, and LM3S817 data sheets. Includes the following changes: * Added information to the Thermal chapter. * Added information to the Power Specifications section in the Electrical chapter. Third release of LM3S317, LM3S617, LM3S618, LM3S817, and LM3S818 data sheets. Includes the following changes: * In the Internal Memory chapter, added information on code protection. * In the ARM Cortex-M3 Processor Core, Architecture Overview, and General-Purpose Timers chapters, added information for the System Timer (SysTick). * In the Timers chapter, added note to the 16-Bit Input Edge Time Mode section.
April 2007
02
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LM3S317 Data Sheet
About This Document
This data sheet provides reference information for the LM3S317 microcontroller, describing the functional blocks of the system-on-chip (SoC) device designed around the ARM(R) CortexTM-M3 core.
Audience
This manual is intended for system software developers, hardware designers, and application developers.
About This Manual
This document is organized into sections that correspond to each major feature.
Related Documents
The following documents are referenced by the data sheet, and available on the documentation CD or from the Luminary Micro web site at www.luminarymicro.com: ARM(R) CortexTM-M3 Technical Reference Manual CoreSightTM Design Kit Technical Reference Manual ARM(R) v7-M Architecture Application Level Reference Manual The following related documents are also referenced: IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture This documentation list was current as of publication date. Please check the Luminary Micro web site for additional documentation, including application notes and white papers.
Documentation Conventions
This document uses the conventions shown in Table 0-1. Table 0-1. Documentation Conventions
Notation General Register Notation REGISTER APB registers are indicated in uppercase bold. For example, PBORCTL is the Power-On and Brown-Out Reset Control register. If a register name contains a lowercase n, it represents more than one register. For example, SRCRn represents any (or all) of the three Software Reset Control registers: SRCR0, SRCR1, and SRCR2. A single bit in a register. Two or more consecutive and related bits. A hexadecimal increment to a register's address, relative to that module's base address as specified in Table 3-1, "Memory Map," on page 40. Meaning
bit bit field offset 0xnnn
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About This Document
Table 0-1. Documentation Conventions
Notation Register N Meaning Registers are numbered consecutively throughout the document to aid in referencing them. The register number has no meaning to software. Register bits marked reserved are reserved for future use. Reserved bits return an indeterminate value, and should never be changed. Only write a reserved bit with its current value. The range of register bits inclusive from xx to yy. For example, 31:15 means bits 15 through 31 in that register. This value in the register bit diagram indicates whether software running on the controller can change the value of the bit field. Software can read this field. Always write the chip reset value. Software can read or write this field. Software can read or write this field. A write of a 0 to a W1C bit does not affect the bit value in the register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. This register type is primarily used for clearing interrupt status bits where the read operation provides the interrupt status and the write of the read value clears only the interrupts being reported at the time the register was read. W1C Software can write this field. A write of a 0 to a W1C bit does not affect the bit value in the register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. A read of the register returns no meaningful data. This register is typically used to clear the corresponding bit in an interrupt register. WO Only a write by software is valid; a read of the register returns no meaningful data. This value in the register bit diagram shows the bit/field value after any reset, unless noted. Bit cleared to 0 on chip reset. Bit set to 1 on chip reset. Nondeterministic.
reserved
yy:xx
Register Bit/Field Types RO R/W R/W1C
Register Bit/Field Reset Value 0 1 - Pin/Signal Notation [] pin signal
Pin alternate function; a pin defaults to the signal without the brackets. Refers to the physical connection on the package. Refers to the electrical signal encoding of a pin.
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Table 0-1. Documentation Conventions
Notation assert a signal Meaning Change the value of the signal from the logically False state to the logically True state. For active High signals, the asserted signal value is 1 (High); for active Low signals, the asserted signal value is 0 (Low). The active polarity (High or Low) is defined by the signal name (see SIGNAL and SIGNAL below). Change the value of the signal from the logically True state to the logically False state. Signal names are in uppercase and in the Courier font. An overbar on a signal name indicates that it is active Low. To assert SIGNAL is to drive it Low; to deassert SIGNAL is to drive it High. Signal names are in uppercase and in the Courier font. An active High signal has no overbar. To assert SIGNAL is to drive it High; to deassert SIGNAL is to drive it Low.
deassert a signal SIGNAL
SIGNAL
Numbers X An uppercase X indicates any of several values is allowed, where X can be any legal pattern. For example, a binary value of 0X00 can be either 0100 or 0000, a hex value of 0xX is 0x0 or 0x1, and so on. Hexadecimal numbers have a prefix of 0x. For example, 0x00FF is the hexadecimal number FF. Binary numbers are indicated with a b suffix, for example, 1011b. Decimal numbers are written without a prefix or suffix.
0x
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Architectural Overview
1
Architectural Overview
The Luminary Micro Stellaris(R) family of microcontrollers--the first ARM(R) CortexTM-M3 based controllers--brings high-performance 32-bit computing to cost-sensitive embedded microcontroller applications. These pioneering parts deliver customers 32-bit performance at a cost equivalent to legacy 8- and 16-bit devices, all in a package with a small footprint. The LM3S317 controller in the Stellaris family offers the advantages of ARM's widely available development tools, System-on-Chip (SoC) infrastructure IP applications, and a large user community. Additionally, the controller uses ARM's Thumb(R)-compatible Thumb-2 instruction set to reduce memory requirements and, thereby, cost. Luminary Micro offers a complete solution to get to market quickly, with a customer development board, white papers and application notes, and a strong support, sales, and distributor network.
1.1
Product Features
The LM3S317 microcontroller includes the following product features: 32-Bit RISC Performance - 32-bit ARM(R) CortexTM-M3 v7M architecture optimized for small-footprint embedded applications - System timer (SysTick) provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism - Thumb(R)-compatible Thumb-2-only instruction set processor core for high code density - 25-MHz operation - Hardware-division and single-cycle-multiplication - Integrated Nested Vectored Interrupt Controller (NVIC) providing deterministic interrupt handling - 25 interrupts with eight priority levels - Memory protection unit (MPU) provides a privileged mode for protected operating system functionality - Unaligned data access, enabling data to be efficiently packed into memory - Atomic bit manipulation (bit-banding) delivers maximum memory utilization and streamlined peripheral control Internal Memory - 16-KB single-cycle flash * * * User-managed flash block protection on a 2-KB block basis User-managed flash data programming User-defined and managed flash-protection block
- 4-KB single-cycle SRAM General-Purpose Timers - Three timers, each of which can be configured: as a single 32-bit timer, as two 16-bit timers, or to initiate an ADC event - 32-bit Timer modes: * Programmable one-shot timer
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* * * * * * * * * * * *
Programmable periodic timer Real-Time Clock when using an external 32.768-KHz clock as the input User-enabled stalling in periodic and one-shot mode when the controller asserts the CPU Halt flag during debug ADC event trigger General-purpose timer function with an 8-bit prescaler Programmable one-shot timer Programmable periodic timer User-enabled stalling when the controller asserts CPU Halt flag during debug ADC event trigger Input edge count capture Input edge time capture Simple PWM mode with software-programmable output inversion of the PWM signal
- 16-bit Timer modes:
- 16-bit Input Capture modes:
- 16-bit PWM mode: ARM FiRM-compliant Watchdog Timer - 32-bit down counter with a programmable load register - Separate watchdog clock with an enable - Programmable interrupt generation logic with interrupt masking - Lock register protection from runaway software - Reset generation logic with an enable/disable - User-enabled stalling when the controller asserts the CPU Halt flag during debug Synchronous Serial Interface (SSI) - Master or slave operation - Programmable clock bit rate and prescale - Separate transmit and receive FIFOs, 16 bits wide, 8 locations deep - Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces - Programmable data frame size from 4 to 16 bits - Internal loopback test mode for diagnostic/debug testing UART - Fully programmable 16C550-type UART - Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs to reduce CPU interrupt service loading - Programmable baud-rate generator with fractional divider - Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface
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Architectural Overview
- FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8 - Standard asynchronous communication bits for start, stop, and parity - False-start-bit detection - Line-break generation and detection ADC - Single- and differential-input configurations - Six 10-bit channels (inputs) when used as single-ended inputs - Sample rate of 250 thousand samples/second - Flexible, configurable analog-to-digital conversion - Four programmable sample conversion sequences from one to eight entries long, with corresponding conversion result FIFOs - Each sequence triggered by software or internal event (timers, analog comparators, PWM or GPIO) Analog Comparator - One independent integrated analog comparator - Configurable for output to: drive an output pin, or generate an interrupt, or initiate an ADC sample sequence - Compare external pin input to external pin input or to internal programmable voltage reference PWM - Three PWM generator blocks, each with one 16-bit counter, two comparators, a PWM generator, and a dead-band generator - One 16-bit counter * * * * * * * * * * Runs in Down or Up/Down mode Output frequency controlled by a 16-bit load value Load value updates can be synchronized Produces output signals at zero and load value Comparator value updates can be synchronized Produces output signals on match Output PWM signal is constructed based on actions taken as a result of the counter and comparator output signals Produces two independent PWM signals Produces two PWM signals with programmable dead-band delays suitable for driving a half-H bridge Can be bypassed, leaving input PWM signals unmodified
- Two comparators
- PWM generator
- Dead-band generator
- Flexible output control block with PWM output enable of each PWM signal
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* * * * * *
PWM output enable of each PWM signal Optional output inversion of each PWM signal (polarity control) Optional fault handling for each PWM signal Synchronization of timers in the PWM generator blocks Synchronization of timer/comparator updates across the PWM generator blocks Interrupt status summary of the PWM generator blocks
- Can initiate an ADC sample sequence GPIOs - 3 to 30 GPIOs, depending on configuration - 5-V-tolerant input/outputs - Programmable interrupt generation as either edge-triggered or level-sensitive - Bit masking in both read and write operations through address lines - Can initiate an ADC sample sequence - Programmable control for GPIO pad configuration: * * * * * Power - On-chip Low Drop-Out (LDO) voltage regulator, with programmable output user-adjustable from 2.25 V to 2.75 V - Low-power options on controller: Sleep and Deep-sleep modes - Low-power options for peripherals: software controls shutdown of individual peripherals - User-enabled LDO unregulated voltage detection and automatic reset - 3.3-V supply brownout detection and reporting via interrupt or reset - On-chip temperature sensor Flexible Reset Sources - Power-on reset (POR) - Reset pin assertion - Brown-out (BOR) detector alerts to system power drops - Software reset - Watchdog timer reset - Internal low drop-out (LDO) regulator output goes unregulated Additional Features - Six reset sources - Programmable clock source control Weak pull-up or pull-down resistors 2-mA, 4-mA, and 8-mA pad drive Slew rate control for the 8-mA drive Open drain enables Digital input enables
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Architectural Overview
- Clock gating to individual peripherals for power savings - IEEE 1149.1-1990 compliant Test Access Port (TAP) controller - Debug access via JTAG and Serial Wire interfaces - Full JTAG boundary scan Industrial-range 48-pin RoHS-compliant LQFP package
1.2
Target Applications
Factory automation and control Industrial control power devices Building and home automation Stepper motors Brushless DC motors AC induction motors
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LM3S317 Data Sheet
1.3
High-Level Block Diagram
Figure 1-1. Stellaris(R) High-Level Block Diagram
ARM Cortex-M3 (including Nested DCode bus Flash Vectored Interrupt Controller (NVIC)) ICode bus
Memory Peripherals
System Control & Clocks
LMI JTAG Test Access Port (TAP) Controller
APB Bridge
SRAM
General-Purpose Timers General-Purpose Input/Outputs (GPIOs) Watchdog Timer
System Peripherals
Peripheral Bus
Universal Asynchronous Receivers/ Transmitters (UARTs)
Synchronous Serial Serial Communications Interface Peripherals (SSI)
Analog-toDigital Converter (ADC) Temperature Sensor
Analog Comparator
Analog Peripherals
Pulse Width Modulator (PWM)
Motor Control Peripherals
LM3S317
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Architectural Overview
1.4
Functional Overview
The following sections provide an overview of the features of the LM3S317 microcontroller. The chapter number in parenthesis indicates where that feature is discussed in detail. Ordering and support information can be found in "Ordering and Contact Information" on page 378.
1.4.1
1.4.1.1
ARM CortexTM-M3
Processor Core (Section 2 on page 32) All members of the Stellaris product family, including the LM3S317 microcontroller, are designed around an ARM CortexTM-M3 processor core. The ARM Cortex-M3 processor provides the core for a high-performance, low-cost platform that meets the needs of minimal memory implementation, reduced pin count, and low power consumption, while delivering outstanding computational performance and exceptional system response to interrupts. Section 2, "ARM Cortex-M3 Processor Core," on page 32 provides an overview of the ARM core; the core is detailed in the ARM(R) CortexTM-M3 Technical Reference Manual.
1.4.1.2
Nested Vectored Interrupt Controller (NVIC) The LM3S317 controller includes the ARM Nested Vectored Interrupt Controller (NVIC) on the ARM Cortex-M3 core. The NVIC and Cortex-M3 prioritize and handle all exceptions. All exceptions are handled in Handler Mode. The processor state is automatically stored to the stack on an exception, and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The vector is fetched in parallel to the state saving, which enables efficient interrupt entry. The processor supports tail-chaining, which enables back-to-back interrupts to be performed without the overhead of state saving and restoration. Software can set eight priority levels on 7 exceptions (system handlers) and 25 interrupts. Section 4, "Interrupts," on page 42 provides an overview of the NVIC controller and the interrupt map. Exceptions and interrupts are detailed in the ARM(R) CortexTM-M3 Technical Reference Manual.
1.4.2
Motor Control Peripherals
To enhance motor control, the LM3S317 controller features Pulse Width Modulation (PWM) outputs.
1.4.2.1
PWM Pulse width modulation (PWM) is a powerful technique for digitally encoding analog signal levels. High-resolution counters are used to generate a square wave, and the duty cycle of the square wave is modulated to encode an analog signal. Typical applications include switching power supplies and motor control. On the LM3S317, PWM motion control functionality can be achieved through dedicated, flexible motion control hardware (the PWM pins) or through the motion control features of the general-purpose timers (using the CCP pins). PWM Pins (Section 15 on page 319) The LM3S317 PWM module consists of three PWM generator blocks and a control block. Each PWM generator block contains one timer (16-bit down or up/down counter), two comparators, a PWM signal generator, a dead-band generator, and an interrupt/ADC-trigger selector. The control block determines the polarity of the PWM signals, and which signals are passed through to the pins.
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Each PWM generator block produces two PWM signals that can either be independent signals or a single pair of complementary signals with dead-band delays inserted. The output of the PWM generation blocks are managed by the output control block before being passed to the device pins. CCP Pins ("16-Bit PWM Mode" on page 161) The General-Purpose Timer Module's CCP (Capture Compare PWM) pins are software programmable to support a simple PWM mode with a software-programmable output inversion of the PWM signal.
1.4.3
Analog Peripherals
To handle analog signals, the LM3S317 controller offers an Analog-to-Digital Converter (ADC) and an analog comparator.
1.4.3.1
ADC (Section 11 on page 207) An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a discrete digital number. The Stellaris ADC module features 10-bit conversion resolution and supports six input channels, plus an internal temperature sensor. Four buffered sample sequences allow rapid sampling of up to six analog input sources without controller intervention. Each sample sequence provides flexible programming with fully configurable input source, trigger events, interrupt generation, and sequence priority.
1.4.3.2
Analog Comparator (Section 14 on page 308) An analog comparator is a peripheral that compares two analog voltages, and provides a logical output that signals the comparison result. The LM3S317 controller provides one independent integrated analog comparator that can be configured to drive an output or generate an interrupt or ADC event. A comparator can compare a test voltage against any one of these voltages: An individual external reference voltage A single external reference voltage A shared internal reference voltage The comparator can provide its output to a device pin, acting as a replacement for an analog comparator on the board, or it can be used to signal the application via interrupts or triggers to the ADC to cause it to start capturing a sample sequence. The interrupt generation and ADC triggering logic is separate. This means, for example, that an interrupt can be generated on a rising edge and the ADC triggered on a falling edge.
1.4.4
Serial Communications Peripherals
The LM3S317 controller supports both asynchronous and synchronous serial communications with one fully programmable 16C550-type UART and SSI serial communications.
1.4.4.1
UART (Section 12 on page 237) A Universal Asynchronous Receiver/Transmitter (UART) is an integrated circuit used for RS-232C serial communications, containing a transmitter (parallel-to-serial converter) and a receiver (serial-to-parallel converter), each clocked separately. The LM3S317 controller includes one fully programmable 16C550-type UART that supports data transfer speeds up to 460.8 Kbps. (Although similar in functionality to a 16C550 UART, it is not register compatible.)
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Architectural Overview
Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs reduce CPU interrupt service loading. The UART can generate individually masked interrupts from the RX, TX, modem status, and error conditions. The module provides a single combined interrupt when any of the interrupts are asserted and are unmasked. 1.4.4.2 SSI (Section 13 on page 273) Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface. The Stellaris SSI module provides the functionality for synchronous serial communications with peripheral devices, and can be configured to use the Freescale SPI, MICROWIRE, or TI synchronous serial interface frame formats. The size of the data frame is also configurable, and can be set between 4 and 16 bits, inclusive. The SSI module performs serial-to-parallel conversion on data received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral device. The TX and RX paths are buffered with internal FIFOs, allowing up to eight 16-bit values to be stored independently. The SSI module can be configured as either a master or slave device. As a slave device, the SSI module can also be configured to disable its output, which allows a master device to be coupled with multiple slave devices. The SSI module also includes a programmable bit rate clock divider and prescaler to generate the output serial clock derived from the SSI module's input clock. Bit rates are generated based on the input clock and the maximum bit rate is determined by the connected peripheral.
1.4.5
1.4.5.1
System Peripherals
Programmable GPIOs (Section 8 on page 114) General-purpose input/output (GPIO) pins offer flexibility for a variety of connections. The Stellaris GPIO module is composed of five physical GPIO blocks, each corresponding to an individual GPIO port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation IP for Real-Time Microcontrollers specification) and supports 3 to 30 programmable input/output pins. The number of GPIOs available depends on the peripherals being used (see Table 17-4 on page 357 for the signals available to each GPIO pin). The GPIO module features programmable interrupt generation as either edge-triggered or level-sensitive on all pins, programmable control for GPIO pad configuration, and bit masking in both read and write operations through address lines.
1.4.5.2
Three Programmable Timers (Section 9 on page 152) Programmable timers can be used to count or time external events that drive the Timer input pins. The Stellaris General-Purpose Timer Module (GPTM) contains three GPTM blocks. Each GPTM block provides two 16-bit timer/counters that can be configured to operate independently as timers or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC). Timers can also be used to trigger analog-to-digital (ADC) conversions. When configured in 32-bit mode, a timer can run as a one-shot timer, periodic timer, or Real-Time Clock (RTC). When in 16-bit mode, a timer can run as a one-shot timer or periodic timer, and can extend its precision by using an 8-bit prescaler. A 16-bit timer can also be configured for event capture or Pulse Width Modulation (PWM) generation.
1.4.5.3
Watchdog Timer (Section 10 on page 184) A watchdog timer can generate nonmaskable interrupts (NMIs) or a reset when a time-out value is reached. The watchdog timer is used to regain control when a system has failed due to a software error or to the failure of an external device to respond in the expected way.
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LM3S317 Data Sheet
The Stellaris Watchdog Timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, and a locking register. The Watchdog Timer can be configured to generate an interrupt to the controller on its first time-out, and to generate a reset signal on its second time-out. Once the Watchdog Timer has been configured, the lock register can be written to prevent the timer configuration from being inadvertently altered.
1.4.6
1.4.6.1
Memory Peripherals
The Stellaris controllers offer both SRAM and Flash memory. SRAM (Section 7.2.1 on page 97) The LM3S317 static random access memory (SRAM) controller supports 4 KB SRAM. The internal SRAM of the Stellaris devices is located at address 0x2000.0000 of the device memory map. To reduce the number of time consuming read-modify-write (RMW) operations, ARM has introduced bit-banding technology in the new Cortex-M3 processor. With a bit-band-enabled processor, certain regions in the memory map (SRAM and peripheral space) can use address aliases to access individual bits in a single, atomic operation.
1.4.6.2
Flash (Section 7.2.2 on page 98) The LM3S317 Flash controller supports 16 KB of flash memory. The flash is organized as a set of 1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the block to be reset to all 1s. These blocks are paired into a set of 2-KB blocks that can be individually protected. The blocks can be marked as read-only or execute-only, providing different levels of code protection. Read-only blocks cannot be erased or programmed, protecting the contents of those blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only be read by the controller instruction fetch mechanism, protecting the contents of those blocks from being read by either the controller or by a debugger.
1.4.7
1.4.7.1
Additional Features
Memory Map (Section 3 on page 40) A memory map lists the location of instructions and data in memory. The memory map for the LM3S317 controller can be found on page 40. Register addresses are given as a hexadecimal increment, relative to the module's base address as shown in the memory map. The ARM(R) CortexTM-M3 Technical Reference Manual provides further information on the memory map.
1.4.7.2
JTAG TAP Controller (Section 5 on page 45) The Joint Test Action Group (JTAG) port provides a standardized serial interface for controlling the Test Access Port (TAP) and associated test logic. The TAP, JTAG instruction register, and JTAG data registers can be used to test the interconnects of assembled printed circuit boards, obtain manufacturing information on the components, and observe and/or control the inputs and outputs of the controller during normal operation. The JTAG port provides a high degree of testability and chip-level access at a low cost. The JTAG port is comprised of the standard five pins: TRST, TCK, TMS, TDI, and TDO. Data is transmitted serially into the controller on TDI and out of the controller on TDO. The interpretation of this data is dependent on the current state of the TAP controller. For detailed information on the operation of the JTAG port and TAP controller, please refer to the IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture.
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29
Architectural Overview
The LMI JTAG controller works with the ARM JTAG controller built into the Cortex-M3 core. This is implemented by multiplexing the TDO outputs from both JTAG controllers. ARM JTAG instructions select the ARM TDO output while LMI JTAG instructions select the LMI TDO outputs. The multiplexer is controlled by the LMI JTAG controller, which has comprehensive programming for the ARM, LMI, and unimplemented JTAG instructions. 1.4.7.3 System Control and Clocks (Section 6 on page 55) System control determines the overall operation of the device. It provides information about the device, controls the clocking of the device and individual peripherals, and handles reset detection and reporting.
1.4.8
Hardware Details
Details on the pins and package can be found in the following sections: Section 16, "Pin Diagram," on page 348 Section 17, "Signal Tables," on page 349 Section 18, "Operating Characteristics," on page 359 Section 19, "Electrical Characteristics," on page 360 Section 20, "Package Information," on page 372
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LM3S317 Data Sheet
1.5
System Block Diagram
Figure 1-2.
VDD_3.3V LDO GND ARM Cortex-M3 (25 MHz) CM3Core NVIC Debug OSC0 OSC1 POR BOR System Control & Clocks GPIO Port A Watchdog Timer IOSC PLL APB Bridge SRAM (4 KB) Bus DCode ICode Flash (16 KB) LDO VDD_2.5V
LM3S317 Controller System-Level Block Diagram
RST
GPIO Port B PB7/TRST Analog Comparator PB6/C0+ PB4/C0PB5/C0o PB2
Peripheral Bus
PA5/SSITx PA4/SSIRx PA3/SSIFss PA2/SSIClk PA1/U0Tx PA0/U0Rx
SSI
UART0 GPIO Port C
PWM1
PB1/PWM3 PB0/PWM2 PB3/Fault
PC6/CCP3 PC3/TDO/SWO PC2/TDI PC1/TMS/SWDIO PC0/TCK/SWCLK PC7/CCP4 PC4/CCP5 PC5/CCP1 GPIO Port E PE0/PWM4 PE1/PWM5 JTAG SWD/SWO
GPIO Port D PWM0 PD0/PWM0 PD1/PWM1 PD2 PD3 GP Timer0 PD4/CCP0
GP Timer2
GP Timer1 PWM2
PD5/CCP2
ADC5 ADC4 ADC3 ADC2 ADC1 ADC0
ADC
LM3S317
Temperature Sensor
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ARM Cortex-M3 Processor Core
2
ARM Cortex-M3 Processor Core
The ARM Cortex-M3 processor provides the core for a high-performance, low-cost platform that meets the needs of minimal memory implementation, reduced pin count, and low power consumption, while delivering outstanding computational performance and exceptional system response to interrupts. Features include: Compact core. Thumb-2 instruction set, delivering the high-performance expected of an ARM core in the memory size usually associated with 8- and 16-bit devices; typically in the range of a few kilobytes of memory for microcontroller class applications. Exceptional interrupt handling, by implementing the register manipulations required for handling an interrupt in hardware. Memory protection unit (MPU) to provide a privileged mode of operation for complex applications. Full-featured debug solution with a: - Serial Wire JTAG Debug Port (SWJ-DP) - Flash Patch and Breakpoint (FPB) unit for implementing breakpoints - Data Watchpoint and Trigger (DWT) unit for implementing watchpoints, trigger resources, and system profiling - Instrumentation Trace Macrocell (ITM) for support of printf style debugging - Trace Port Interface Unit (TPIU) for bridging to a Trace Port Analyzer The Stellaris family of microcontrollers builds on this core to bring high-performance 32-bit computing to cost-sensitive embedded microcontroller applications, such as factory automation and control, industrial control power devices, building and home automation. For more information on the ARM Cortex-M3 processor core, see the ARM(R) CortexTM-M3 Technical Reference Manual. For information on SWJ-DP, see the CoreSightTM Design Kit Technical Reference Manual.
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LM3S317 Data Sheet
2.1
Block Diagram
Figure 2-1. CPU Block Diagram
Nested Vectored Interrupt Controller
Interrupts Sleep Debug CM3 Core Instructions Memory Protection Unit Data Trace Port Interface Unit
ARM Cortex-M3
Serial Wire Output Trace Port (SWO)
Flash Patch and Breakpoint
Data Watchpoint and Trace
Instrumentation Trace Macrocell
Private Peripheral Bus (external) ROM Table
Private Peripheral Bus (internal ) Bus Matrix
Adv. Peripheral Bus I-code bus D-code bus System bus
Serial Wire JTAG Debug Port
Adv. HighPerf. Bus Access Port
2.2
Functional Description
Important: The ARM(R) CortexTM-M3 Technical Reference Manual describes all the features of an ARM Cortex-M3 in detail. However, these features differ based on the implementation. This section describes the Stellaris implementation. Luminary Micro has implemented the ARM Cortex-M3 core as shown in Figure 2-1. As noted in the ARM(R) CortexTM-M3 Technical Reference Manual, several Cortex-M3 components are flexible in their implementation: SW/JTAG-DP, ETM, TPIU, the ROM table, the MPU, and the Nested Vectored Interrupt Controller (NVIC). Each of these is addressed in the sections that follow.
2.2.1
Serial Wire and JTAG Debug
Luminary Micro has replaced the ARM SW-DP and JTAG-DP with the ARM CoreSightTM-compliant Serial Wire JTAG Debug Port (SWJ-DP) interface. This means Chapter 12, "Debug Port," of the ARM(R) CortexTM-M3 Technical Reference Manual does not apply to Stellaris devices. The SWJ-DP interface combines the SWD and JTAG debug ports into one module. See the CoreSightTM Design Kit Technical Reference Manual for details on SWJ-DP.
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ARM Cortex-M3 Processor Core
2.2.2
Embedded Trace Macrocell (ETM)
ETM was not implemented in the Stellaris devices. This means Chapters 15 and 16 of the ARM(R) CortexTM-M3 Technical Reference Manual can be ignored.
2.2.3
Trace Port Interface Unit (TPIU)
The TPIU acts as a bridge between the Cortex-M3 trace data from the ITM, and an off-chip Trace Port Analyzer. The Stellaris devices have implemented TPIU as shown in Figure 2-2. This is similar to the non-ETM version described in the ARM(R) CortexTM-M3 Technical Reference Manual, however, SWJ-DP only provides SWV output for the TPIU. Figure 2-2. TPIU Block Diagram
Debug ATB Slave Port
ATB Interface
Asynchronous FIFO
Trace Out (serializer)
Serial Wire Trace Port (SWO)
APB Slave Port
APB Interface
2.2.4
ROM Table
The default ROM table was implemented as described in the ARM(R) CortexTM-M3 Technical Reference Manual.
2.2.5
Memory Protection Unit (MPU)
The Memory Protection Unit (MPU) is included on the LM3S317 controller and supports the standard ARMv7 Protected Memory System Architecture (PMSA) model. The MPU provides full support for protection regions, overlapping protection regions, access permissions, and exporting memory attributes to the system.
2.2.6
Nested Vectored Interrupt Controller (NVIC)
The Nested Vectored Interrupt Controller (NVIC): Facilitates low-latency exception and interrupt handling Controls power management Implements system control registers The NVIC supports up to 240 dynamically reprioritizable interrupts each with up to 256 levels of priority. The NVIC and the processor core interface are closely coupled, which enables low latency
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LM3S317 Data Sheet
interrupt processing and efficient processing of late arriving interrupts. The NVIC maintains knowledge of the stacked (nested) interrupts to enable tail-chaining of interrupts. You can only fully access the NVIC from privileged mode, but you can pend interrupts in user-mode if you enable the Configuration Control Register (see the ARM(R) CortexTM-M3 Technical Reference Manual). Any other user-mode access causes a bus fault. All NVIC registers are accessible using byte, halfword, and word unless otherwise stated. All NVIC registers and system debug registers are little endian regardless of the endianness state of the processor. 2.2.6.1 Interrupts The ARM(R) CortexTM-M3 Technical Reference Manual describes the maximum number of interrupts and interrupt priorities. The LM3S317 microcontroller supports 25 interrupts with eight priority levels. 2.2.6.2 System Timer (SysTick) Cortex-M3 includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter can be used in several different ways, for example: An RTOS tick timer which fires at a programmable rate (for example, 100 Hz) and invokes a SysTick routine. A high-speed alarm timer using the system clock. A variable rate alarm or signal timer--the duration is range-dependent on the reference clock used and the dynamic range of the counter. A simple counter. Software can use this to measure time to completion and time used. An internal clock source control based on missing/meeting durations. The COUNTFLAG bit-field in the control and status register can be used to determine if an action completed within a set duration, as part of a dynamic clock management control loop. Functional Description The timer consists of three registers: A control and status counter to configure its clock, enable the counter, enable the SysTick interrupt, and determine counter status. The reload value for the counter, used to provide the counter's wrap value. The current value of the counter. A fourth register, the SysTick Calibration Value Register, is not implemented in the Stellaris devices. When enabled, the timer counts down from the reload value to zero, reloads (wraps) to the value in the SysTick Reload Value register on the next clock edge, then decrements on subsequent clocks. Writing a value of zero to the Reload Value register disables the counter on the next wrap. When the counter reaches zero, the COUNTFLAG status bit is set. The COUNTFLAG bit clears on reads. Writing to the Current Value register clears the register and the COUNTFLAG status bit. The write does not trigger the SysTick exception logic. On a read, the current value is the value of the register at the time the register is accessed.
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ARM Cortex-M3 Processor Core
If the core is in debug state (halted), the counter will not decrement. The timer is clocked with respect to a reference clock. The reference clock can be the core clock or an external clock source.
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LM3S317 Data Sheet
Register 1: SysTick Control and Status Register Use the SysTick Control and Status Register to enable the SysTick features.
SysTick Control and Status
Address: 0xE000E010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1
COUNTFLAG
R/W 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CLKSOURCE
TICKINT ENABLE
R/W 0 R/W 0
R/W 0
Bit/Field 31:17 16
Name reserved COUNTFLAG
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Returns 1 if timer counted to 0 since last time this was read. Clears on read by application. If read by the debugger using the DAP, this bit is cleared on read-only if the MasterType bit in the AHB-AP Control Register is set to 0. Otherwise, the COUNTFLAG bit is not changed by the debugger read. Reserved bits return an indeterminate value, and should never be changed. 0 = external reference clock. (Not implemented for Stellaris microcontrollers.) 1 = core clock. If no reference clock is provided, it is held at 1 and so gives the same time as the core clock. The core clock must be at least 2.5 times faster than the reference clock. If it is not, the count values are Unpredictable.
15:3 2
reserved CLKSOURCE
RO R/W
0 0
1
TICKINT
R/W
0
1 = counting down to 0 pends the SysTick handler. 0 = counting down to 0 does not pend the SysTick handler. Software can use the COUNTFLAG to determine if ever counted to 0.
0
ENABLE
R/W
0
1 = counter operates in a multi-shot way. That is, counter loads with the Reload value and then begins counting down. On reaching 0, it sets the COUNTFLAG to 1 and optionally pends the SysTick handler, based on TICKINT. It then loads the Reload value again, and begins counting. 0 = counter disabled.
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ARM Cortex-M3 Processor Core
Register 2: SysTick Reload Value Register Use the SysTick Reload Value Register to specify the start value to load into the current value register when the counter reaches 0. It can be any value between 1 and 0x00FFFFFF. A start value of 0 is possible, but has no effect because the SysTick interrupt and COUNTFLAG are activated when counting from 1 to 0. Therefore, as a multi-shot timer, repeated over and over, it fires every N+1 clock pulse, where N is any value from 1 to 0x00FFFFFF. So, if the tick interrupt is required every 100 clock pulses, 99 must be written into the RELOAD. If a new value is written on each tick interrupt, so treated as single shot, then the actual count down must be written. For example, if a tick is next required after 400 clock pulses, 400 must be written into the RELOAD.
SysTick Reload Value
Address: 0xE000E014
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 R/W 7 R/W 6 R/W 5
RELOAD
R/W 4 R/W 3 R/W 2 R/W 1 R/W 0
RELOAD Type Reset
R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W -
Bit/Field 31:24 23:0
Name reserved RELOAD
Type RO W1C
Reset 0 -
Description Reserved bits return an indeterminate value, and should never be changed. Value to load into the SysTick Current Value Register when the counter reaches 0.
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LM3S317 Data Sheet
Register 3: SysTick Current Value Register Use the SysTick Current Value Register to find the current value in the register.
SysTick Current Value
Address: 0xE000E018
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 W1C 7 W1C 6 W1C 5
CURRENT
W1C 4 W1C 3 W1C 2 W1C 1 W1C 0
CURRENT Type Reset
W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C W1C -
SysTick Current Value Register bit assignments
Bit/Field 31:24 23:0 Name reserved CURRENT Type RO W1C Reset 0 Description Reserved bits return an indeterminate value, and should never be changed. Current value at the time the register is accessed. No read-modify-write protection is provided, so change with care. This register is write-clear. Writing to it with any value clears the register to 0. Clearing this register also clears the COUNTFLAG bit of the SysTick Control and Status Register.
2.2.6.3
SysTick Calibration Value Register The SysTick Calibration Value register is not implemented.
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Memory Map
3
Memory Map
The memory map for the LM3S317 is provided in Table 3-1. In this manual, register addresses are given as a hexadecimal increment, relative to the module's base address as shown in the memory map. See also Chapter 4, "Memory Map" in the ARM(R) CortexTM-M3 Technical Reference Manual.
Table 3-1. Memory Map (Sheet 1 of 2)
Start Memory 0x00000000 0x00004000 0x20000000 0x20001000 0x22000000 0x22020000 FiRM Peripherals 0x40000000 0x40001000 0x40004000 0x40005000 0x40006000 0x40007000 0x40008000 0x40009000 0x4000C000 0x4000D000 0x40010000 Peripherals 0x40020000 0x40024000 0x40025000 0x40028000 0x40029000 0x40023FFF 0x40024FFF 0x40027FFF 0x40028FFF 0x4002BFFF Reserveda GPIO Port E Reserveda PWM Reserveda page 121 page 324 0x40000FFF 0x40003FFF 0x40004FFF 0x40005FFF 0x40006FFF 0x40007FFF 0x40008FFF 0x4000BFFF 0x4000CFFF 0x4000FFFF 0x4001FFFF Watchdog timer Reserved for three additional watchdog timers (per FiRM specification)a GPIO Port A GPIO Port B GPIO Port C GPIO Port D SSI Reserved for three additional SSIs (per FiRM specification)a UART0 Reserved for additional UART (per FiRM specification)a Reserved for future FiRM peripheralsa page 284 page 243 page 186 page 121 page 121 page 121 0x00003FFF 0x1FFFFFFF 0x20000FFF 0x200FFFFF 0x2201FFFF 0x23FFFFFF On-chip flash Reserveda Bit-banded on-chip SRAM Reserveda Bit-band alias of 0x20000000 through 0x20000FFF Reserveda page 102 End Description For details on registers, see ...
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LM3S317 Data Sheet
Table 3-1. Memory Map (Sheet 2 of 2)
Start 0x4002C000 0x40030000 0x40031000 0x40032000 0x40033000 0x40038000 0x40039000 0x4003C000 0x4003D000 0x400FD000 0x400FE000 0x40100000 0x42000000 0x44000000 End 0x4002FFFF 0x40030FFF 0x40031FFF 0x40032FFF 0x40037FFF 0x40038FFF 0x4003BFFF 0x4003CFFF 0x400FCFFF 0x400FDFFF 0x400FFFFF 0x41FFFFFF 0x43FFFFFF 0xDFFFFFFF Description Reserveda Timer0 Timer1 Timer2 Reserveda ADC Reserveda Analog comparator Reserveda Flash control System control Reserveda Bit-band alias of 0x40000000 through 0x400FFFFF Reserveda For details on registers, see ... page 163 page 163 page 163 page 212 page 311 page 102 page 62 -
Private Peripheral Bus 0xE0000000 0xE0001000 0xE0002000 0xE0003000 0xE000E000 0xE000F000 0xE0040000 0xE0041000 0xE0042000 0xE0100000 0xE0000FFF 0xE0001FFF 0xE0002FFF 0xE000DFFF 0xE000EFFF 0xE003FFFF 0xE0040FFF 0xE0041FFF 0xE00FFFFF 0xFFFFFFFF Instrumentation Trace Macrocell (ITM) Data Watchpoint and Trace (DWT) Flash Patch and Breakpoint (FPB) Reserveda Nested Vectored Interrupt Controller (NVIC) Reserveda Trace Port Interface Unit (TPIU) Reserveda Reserved
a
ARM(R) CortexTM-M3 Technical Reference Manual
-
Reserved for vendor peripheralsa
a. All reserved space returns a bus fault when read or written.
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Interrupts
4
Interrupts
The ARM Cortex-M3 processor and the Nested Vectored Interrupt Controller (NVIC) prioritize and handle all exceptions. All exceptions are handled in Handler Mode. The processor state is automatically stored to the stack on an exception, and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The vector is fetched in parallel to the state saving, which enables efficient interrupt entry. The processor supports tail-chaining, which enables back-to-back interrupts to be performed without the overhead of state saving and restoration. Table 4-1 lists all the exceptions. Software can set eight priority levels on seven of these exceptions (system handlers) as well as on 25 interrupts (listed in Table 4-2). Priorities on the system handlers are set with the NVIC System Handler Priority registers. Interrupts are enabled through the NVIC Interrupt Set Enable register and prioritized with the NVIC Interrupt Priority registers. You can also group priorities by splitting priority levels into pre-emption priorities and subpriorities. All the interrupt registers are described in Chapter 8, "Nested Vectored Interrupt Controller" in the ARM(R) CortexTM-M3 Technical Reference Manual. Internally, the highest user-settable priority (0) is treated as fourth priority, after a Reset, NMI, and a Hard Fault. Note that 0 is the default priority for all the settable priorities. If you assign the same priority level to two or more interrupts, their hardware priority (the lower the position number) determines the order in which the processor activates them. For example, if both GPIO Port A and GPIO Port B are priority level 1, then GPIO Port A has higher priority. See Chapter 5, "Exceptions" and Chapter 8, "Nested Vectored Interrupt Controller" in the ARM(R) CortexTM-M3 Technical Reference Manual for more information on exceptions and interrupts. Table 4-1. Exception Types
Position 0 1 Prioritya Description Stack top is loaded from first entry of vector table on reset. Invoked on power up and warm reset. On first instruction, drops to lowest priority (and then is called the base level of activation). This is asynchronous. Cannot be stopped or preempted by any exception but reset. This is asynchronous. An NMI is only producible by software, using the NVIC Interrupt Control State register. Hard Fault 3
Exception Type
Reset
-3 (highest)
Non-Maskable Interrupt (NMI)
2
-2
-1
All classes of Fault, when the fault cannot activate due to priority or the configurable fault handler has been disabled. This is synchronous. MPU mismatch, including access violation and no match. This is synchronous. The priority of this exception can be changed.
Memory Management
4
settable
Bus Fault
5
settable
Pre-fetch fault, memory access fault, and other address/memory related faults. This is synchronous when precise and asynchronous when imprecise. You can enable or disable this fault.
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LM3S317 Data Sheet
Table 4-1.
Exception Types (Continued)
Position 6 Prioritya settable Description Usage fault, such as undefined instruction executed or illegal state transition attempt. This is synchronous. Reserved. System service call with SVC instruction. This is synchronous. Debug monitor (when not halting). This is synchronous, but only active when enabled. It does not activate if lower priority than the current activation. Reserved. Pendable request for system service. This is asynchronous and only pended by software. System tick timer has fired. This is asynchronous. Asserted from outside the ARM Cortex-M3 core and fed through the NVIC (prioritized). These are all asynchronous. Table 4-2 lists the interrupts on the LM3S317 controller.
Exception Type Usage Fault
SVCall Debug Monitor
7-10 11 12
settable settable
PendSV SysTick Interrupts
13 14 15 16 and above
settable settable settable
a. 0 is the default priority for all the settable priorities.
Table 4-2.
Interrupts
Description GPIO Port A GPIO Port B GPIO Port C GPIO Port D GPIO Port E UART0 Reserved SSI Reserved PWM Fault PWM Generator 0 PWM Generator 1 PWM Generator 2
Interrupt (Bit in Interrupt Registers) 0 1 2 3 4 5 6 7 8 9 10 11 12
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Interrupts
Table 4-2.
Interrupts (Continued)
Description Reserved ADC Sequence 0 ADC Sequence 1 ADC Sequence 2 ADC Sequence 3 Watchdog timer Timer0a Timer0b Timer1a Timer1b Timer2a Timer2b Analog Comparator 0 Reserved System Control Flash Control Reserved
Interrupt (Bit in Interrupt Registers) 13 14 15 16 17 18 19 20 21 22 23 24 25 26-27 28 29 30-31
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LM3S317 Data Sheet
5
JTAG Interface
The Joint Test Action Group (JTAG) port is an IEEE standard that defines a Test Access Port and Boundary Scan Architecture for digital integrated circuits and provides a standardized serial interface for controlling the associated test logic. The TAP, Instruction Register (IR), and Data Registers (DR) can be used to test the interconnections of assembled printed circuit boards and obtain manufacturing information on the components. The JTAG Port also provides a means of accessing and controlling design-for-test features such as I/O pin observation and control, scan testing, and debugging. The JTAG port is comprised of the standard five pins: TRST, TCK, TMS, TDI, and TDO. Data is transmitted serially into the controller on TDI and out of the controller on TDO. The interpretation of this data is dependent on the current state of the TAP controller. For detailed information on the operation of the JTAG port and TAP controller, please refer to the IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture. The LMI JTAG controller works with the ARM JTAG controller built into the Cortex-M3 core. This is implemented by multiplexing the TDO outputs from both JTAG controllers. ARM JTAG instructions select the ARM TDO output while LMI JTAG instructions select the LMI TDO outputs. The multiplexer is controlled by the LMI JTAG controller, which has comprehensive programming for the ARM, LMI, and unimplemented JTAG instructions. The JTAG module has the following features: IEEE 1149.1-1990 compatible Test Access Port (TAP) controller Four-bit Instruction Register (IR) chain for storing JTAG instructions IEEE standard instructions: - BYPASS instruction - IDCODE instruction - SAMPLE/PRELOAD instruction - EXTEST instruction - INTEST instruction ARM additional instructions: - APACC instruction - DPACC instruction - ABORT instruction Integrated ARM Serial Wire Debug (SWD) See the ARM(R) CortexTM-M3 Technical Reference Manual for more information on the ARM JTAG controller.
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JTAG Interface
5.1
Figure 5-1.
Block Diagram
JTAG Module Block Diagram
TRST TCK TMS TDI
TAP Controller
Instruction Register (IR)
BYPASS Data Register Boundary Scan Data Register IDCODE Data Register ABORT Data Register DPACC Data Register APACC Data Register
TDO
Cortex-M3 Debug Port
5.2
Functional Description
A high-level conceptual drawing of the JTAG module is shown in Figure 5-1. The JTAG module is composed of the Test Access Port (TAP) controller and serial shift chains with parallel update registers. The TAP controller is a simple state machine controlled by the TRST, TCK and TMS inputs. The current state of the TAP controller depends on the current value of TRST and the sequence of values captured on TMS at the rising edge of TCK. The TAP controller determines when the serial shift chains capture new data, shift data from TDI towards TDO, and update the parallel load registers. The current state of the TAP controller also determines whether the Instruction Register (IR) chain or one of the Data Register (DR) chains is being accessed. The serial shift chains with parallel load registers are comprised of a single Instruction Register (IR) chain and multiple Data Register (DR) chains. The current instruction loaded in the parallel load register determines which DR chain is captured, shifted, or updated during the sequencing of the TAP controller. Some instructions, like EXTEST and INTEST, operate on data currently in a DR chain and do not capture, shift, or update any of the chains. Instructions that are not implemented decode to the BYPASS instruction to ensure that the serial path between TDI and TDO is always connected (see Table 5-2 on page 51 for a list of implemented instructions). See "JTAG and Boundary Scan" on page 367 for JTAG timing diagrams.
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5.2.1
JTAG Interface Pins
The JTAG interface consists of five standard pins: TRST, TCK, TMS, TDI, and TDO. These pins and their associated reset state are given in Table 5-1. Detailed information on each pin follows. Table 5-1. JTAG Port Pins Reset State
Data Direction Input Input Input Input Output Internal Pull-Up Enabled Enabled Enabled Enabled Enabled Internal Pull-Down Disabled Disabled Disabled Disabled Disabled Drive Strength N/A N/A N/A N/A 2-mA driver Drive Value N/A N/A N/A N/A High-Z
Pin Name TRST TCK TMS TDI TDO
5.2.1.1
Test Reset Input (TRST) The TRST pin is an asynchronous active Low input signal for initializing and resetting the JTAG TAP controller and associated JTAG circuitry. When TRST is asserted, the TAP controller resets to the Test-Logic-Reset state and remains there while TRST is asserted. When the TAP controller enters the Test-Logic-Reset state, the JTAG Instruction Register (IR) resets to the default instruction, IDCODE. By default, the internal pull-up resistor on the TRST pin is enabled after reset. Changes to the pull-up resistor settings on GPIO Port B should ensure that the internal pull-up resistor remains enabled on PB7/TRST; otherwise JTAG communication could be lost.
5.2.1.2
Test Clock Input (TCK) The TCK pin is the clock for the JTAG module. This clock is provided so the test logic can operate independently of any other system clocks. In addition, it ensures that multiple JTAG TAP controllers that are daisy-chained together can synchronously communicate serial test data between components. During normal operation, TCK is driven by a free-running clock with a nominal 50% duty cycle. When necessary, TCK can be stopped at 0 or 1 for extended periods of time. While TCK is stopped at 0 or 1, the state of the TAP controller does not change and data in the JTAG Instruction and Data Registers is not lost. By default, the internal pull-up resistor on the TCK pin is enabled after reset. This assures that no clocking occurs if the pin is not driven from an external source. The internal pull-up and pull-down resistors can be turned off to save internal power as long as the TCK pin is constantly being driven by an external source.
5.2.1.3
Test Mode Select (TMS) The TMS pin selects the next state of the JTAG TAP controller. TMS is sampled on the rising edge of TCK. Depending on the current TAP state and the sampled value of TMS, the next state is entered. Because the TMS pin is sampled on the rising edge of TCK, the IEEE Standard 1149.1 expects the value on TMS to change on the falling edge of TCK. Holding TMS high for five consecutive TCK cycles drives the TAP controller state machine to the Test-Logic-Reset state. When the TAP controller enters the Test-Logic-Reset state, the JTAG Instruction Register (IR) resets to the default instruction, IDCODE. Therefore, this sequence can be used as a reset mechanism, similar to asserting TRST. The JTAG Test Access Port state machine can be seen in its entirety in Figure 5-2 on page 49.
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JTAG Interface
By default, the internal pull-up resistor on the TMS pin is enabled after reset. Changes to the pull-up resistor settings on GPIO Port C should ensure that the internal pull-up resistor remains enabled on PC1/TMS; otherwise JTAG communication could be lost. 5.2.1.4 Test Data Input (TDI) The TDI pin provides a stream of serial information to the IR chain and the DR chains. TDI is sampled on the rising edge of TCK and, depending on the current TAP state and the current instruction, presents this data to the proper shift register chain. Because the TDI pin is sampled on the rising edge of TCK, the IEEE Standard 1149.1 expects the value on TDI to change on the falling edge of TCK. By default, the internal pull-up resistor on the TDI pin is enabled after reset. Changes to the pull-up resistor settings on GPIO Port C should ensure that the internal pull-up resistor remains enabled on PC2/TDI; otherwise JTAG communication could be lost. 5.2.1.5 Test Data Output (TDO) The TDO pin provides an output stream of serial information from the IR chain or the DR chains. The value of TDO depends on the current TAP state, the current instruction, and the data in the chain being accessed. In order to save power when the JTAG port is not being used, the TDO pin is placed in an inactive drive state when not actively shifting out data. Because TDO can be connected to the TDI of another controller in a daisy-chain configuration, the IEEE Standard 1149.1 expects the value on TDO to change on the falling edge of TCK. By default, the internal pull-up resistor on the TDO pin is enabled after reset. This assures that the pin remains at a constant logic level when the JTAG port is not being used. The internal pull-up and pull-down resistors can be turned off to save internal power if a High-Z output value is acceptable during certain TAP controller states.
5.2.2
JTAG TAP Controller
The JTAG TAP controller state machine is shown in Figure 5-2 on page 49. The TAP controller state machine is reset to the Test-Logic-Reset state on the assertion of a Power-On-Reset (POR) or the assertion of TRST. Asserting the correct sequence on the TMS pin allows the JTAG module to shift in new instructions, shift in data, or idle during extended testing sequences. For detailed information on the function of the TAP controller and the operations that occur in each state, please refer to IEEE Standard 1149.1.
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Figure 5-2.
Test Access Port State Machine
Test Logic 1 0 Run Test Idle 0 1 Select DR Scan 0 1 Capture DR 0 Shift DR 1 Exit 1 DR 0 Pause DR 1 0 Exit 2 DR 1 Update DR 1 0 0 0 0 1 1 1 Select IR Scan 0 Capture IR 0 Shift IR 1 Exit 1 IR 0 Pause IR 1 Exit 2 IR 1 Update IR 1 0 0 0 1 1
5.2.3
Shift Registers
The Shift Registers consist of a serial shift register chain and a parallel load register. The serial shift register chain samples specific information during the TAP controller's CAPTURE states and allows this information to be shifted out of TDO during the TAP controller's SHIFT states. While the sampled data is being shifted out of the chain on TDO, new data is being shifted into the serial shift register on TDI. This new data is stored in the parallel load register during the TAP controller's UPDATE states. Each of the shift registers is discussed in detail in "Shift Registers" on page 49.
5.2.4
Operational Considerations
There are certain operational considerations when using the JTAG module. Because the JTAG pins can be programmed to be GPIOs, board configuration and reset conditions on these pins must be considered. In addition, because the JTAG module has integrated ARM Serial Wire Debug, the method for switching between these two operational modes requires clarification.
5.2.4.1
GPIO Functionality When the controller is reset with either a POR or RST, the JTAG port pins default to their JTAG configurations. The default configuration includes enabling the pull-up resistors (setting GPIOPUR
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JTAG Interface
to 1 for PB7 and PC[3:0]) and enabling the alternate hardware function (setting GPIOAFSEL to 1 for PB7 and PC[3:0]) on the JTAG pins. It is possible for software to configure these pins as GPIOs after reset by writing 0s to PB7 and PC[3:0]in the GPIOAFSEL register. If the user does not require the JTAG port for debugging or board-level testing, this provides five more GPIOs for use in the design. Caution - If the JTAG pins are used as GPIOs in a design, PB7 and PC2 cannot have external pull-down resistors connected to both of them at the same time. If both pins are pulled Low during reset, the controller has unpredictable behavior. If this happens, remove one or both of the pull-down resistors, and apply RST or power-cycle the part In addition, it is possible to create a software sequence that prevents the debugger from connecting to the Stellaris microcontroller. If the program code loaded into flash immediately changes the JTAG pins to their GPIO functionality, the debugger does not have enough time to connect and halt the controller before the JTAG pin functionality switches. This locks the debugger out of the part. This can be avoided with a software routine that restores JTAG functionality using an external trigger. 5.2.4.2 ARM Serial Wire Debug (SWD) In order to seamlessly integrate the ARM Serial Wire Debug (SWD) functionality, a serial-wire debugger must be able to connect to the Cortex-M3 core without having to perform, or have any knowledge of, JTAG cycles. This is accomplished with a SWD preamble that is issued before the SWD session begins. The preamble used to enable the SWD interface of the SWJ-DP module starts with the TAP controller in the Test-Logic-Reset state. From here, the preamble sequences the TAP controller through the following states: Run Test Idle, Select DR, Select IR, Capture IR, Exit1 IR, Update IR, Run Test Idle, Select DR, Select IR, Capture IR, Exit1 IR, Update IR, Run Test Idle, Select DR, Select IR, and Test-Logic-Reset states. Stepping through the JTAG TAP Instruction Register (IR) load sequences of the TAP state machine twice without shifting in a new instruction enables the SWD interface and disables the JTAG interface. For more information on this operation and the SWD interface, see the ARM(R) CortexTM-M3 Technical Reference Manual and the ARM(R) CoreSight Technical Reference Manual. Because this sequence is a valid series of JTAG operations that could be issued, the ARM JTAG TAP controller is not fully compliant to the IEEE Standard 1149.1. This is the only instance where the ARM JTAG TAP controller does not meet full compliance with the specification. Due to the low probability of this sequence occurring during normal operation of the TAP controller, it should not affect normal performance of the JTAG interface.
5.3
Initialization and Configuration
After a Power-On-Reset or an external reset (RST), the JTAG pins are automatically configured for JTAG communication. No user-defined initialization or configuration is needed. However, if the user application changes these pins to their GPIO function, they must be configured back to their JTAG functionality before JTAG communication can be restored. This is done by enabling the five JTAG pins (PB7 and PC[3:0]) for their alternate function using the GPIOAFSEL register.
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5.4
Register Descriptions
There are no APB-accessible registers in the JTAG TAP Controller or Shift Register chains. The registers within the JTAG controller are all accessed serially through the TAP Controller. The registers can be broken down into two main categories: Instruction Registers and Data Registers.
5.4.1
Instruction Register (IR)
The JTAG TAP Instruction Register (IR) is a four-bit serial scan chain with a parallel load register connected between the JTAG TDI and TDO pins. When the TAP Controller is placed in the correct states, bits can be shifted into the Instruction Register. Once these bits have been shifted into the chain and updated, they are interpreted as the current instruction. The decode of the Instruction Register bits is shown in Table 5-2. A detailed explanation of each instruction, along with its associated Data Register, follows.
Table 5-2. JTAG Instruction Register Commands
IR[3:0] 0000 0001 0010 1000 1010 1011 1110 1111 All Others Instruction EXTEST INTEST SAMPLE / PRELOAD ABORT DPACC APACC IDCODE BYPASS Reserved Description Drives the values preloaded into the Boundary Scan Chain by the SAMPLE/PRELOAD instruction onto the pads. Drives the values preloaded into the Boundary Scan Chain by the SAMPLE/PRELOAD instruction into the controller. Captures the current I/O values and shifts the sampled values out of the Boundary Scan Chain while new preload data is shifted in. Shifts data into the ARM Debug Port Abort Register. Shifts data into and out of the ARM DP Access Register. Shifts data into and out of the ARM AC Access Register. Loads manufacturing information defined by the IEEE Standard 1149.1 into the IDCODE chain and shifts it out. Connects TDI to TDO through a single Shift Register chain. Defaults to the BYPASS instruction to ensure that TDI is always connected to TDO.
5.4.1.1
EXTEST Instruction The EXTEST instruction does not have an associated Data Register chain. The EXTEST instruction uses the data that has been preloaded into the Boundary Scan Data Register using the SAMPLE/PRELOAD instruction. When the EXTEST instruction is present in the Instruction Register, the preloaded data in the Boundary Scan Data Register associated with the outputs and output enables are used to drive the GPIO pads rather than the signals coming from the core. This allows tests to be developed that drive known values out of the controller, which can be used to verify connectivity.
5.4.1.2
INTEST Instruction The INTEST instruction does not have an associated Data Register chain. The INTEST instruction uses the data that has been preloaded into the Boundary Scan Data Register using the SAMPLE/ PRELOAD instruction. When the INTEST instruction is present in the Instruction Register, the preloaded data in the Boundary Scan Data Register associated with the inputs are used to drive the signals going into the core rather than the signals coming from the GPIO pads. This allows
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tests to be developed that drive known values into the controller, which can be used for testing. It is important to note that although the RST input pin is on the Boundary Scan Data Register chain, it is only observable. 5.4.1.3 SAMPLE/PRELOAD Instruction The SAMPLE/PRELOAD instruction connects the Boundary Scan Data Register chain between TDI and TDO. This instruction samples the current state of the pad pins for observation and preloads new test data. Each GPIO pad has an associated input, output, and output enable signal. When the TAP controller enters the Capture DR state during this instruction, the input, output, and output-enable signals to each of the GPIO pads are captured. These samples are serially shifted out of TDO while the TAP controller is in the Shift DR state and can be used for observation or comparison in various tests. While these samples of the inputs, outputs, and output enables are being shifted out of the Boundary Scan Data Register, new data is being shifted into the Boundary Scan Data Register from TDI. Once the new data has been shifted into the Boundary Scan Data Register, the data is saved in the parallel load registers when the TAP controller enters the Update DR state. This update of the parallel load register preloads data into the Boundary Scan Data Register that is associated with each input, output, and output enable. This preloaded data can be used with the EXTEST and INTEST instructions to drive data into or out of the controller. Please see "Boundary Scan Data Register" on page 53 for more information. 5.4.1.4 ABORT Instruction The ABORT instruction connects the associated ABORT Data Register chain between TDI and TDO. This instruction provides read and write access to the ABORT Register of the ARM Debug Access Port (DAP). Shifting the proper data into this Data Register clears various error bits or initiates a DAP abort of a previous request. Please see the "ABORT Data Register" on page 54 for more information. 5.4.1.5 DPACC Instruction The DPACC instruction connects the associated DPACC Data Register chain between TDI and TDO. This instruction provides read and write access to the DPACC Register of the ARM Debug Access Port (DAP). Shifting the proper data into this register and reading the data output from this register allows read and write access to the ARM debug and status registers. Please see "DPACC Data Register" on page 54 for more information. 5.4.1.6 APACC Instruction The APACC instruction connects the associated APACC Data Register chain between TDI and TDO. This instruction provides read and write access to the APACC Register of the ARM Debug Access Port (DAP). Shifting the proper data into this register and reading the data output from this register allows read and write access to internal components and buses through the Debug Port. Please see "APACC Data Register" on page 54 for more information. 5.4.1.7 IDCODE Instruction The IDCODE instruction connects the associated IDCODE Data Register chain between TDI and TDO. This instruction provides information on the manufacturer, part number, and version of the ARM core. This information can be used by testing equipment and debuggers to automatically configure their input and output data streams. IDCODE is the default instruction that is loaded into the JTAG Instruction Register when a power-on-reset (POR) is asserted, TRST is asserted, or the Test-Logic-Reset state is entered. Please see "IDCODE Data Register" on page 53 for more information.
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5.4.1.8
BYPASS Instruction The BYPASS instruction connects the associated BYPASS Data Register chain between TDI and TDO. This instruction is used to create a minimum length serial path between the TDI and TDO ports. The BYPASS Data Register is a single-bit shift register. This instruction improves test efficiency by allowing components that are not needed for a specific test to be bypassed in the JTAG scan chain by loading them with the BYPASS instruction. Please see "BYPASS Data Register" on page 53 for more information.
5.4.2
Data Registers
The JTAG module contains six Data Registers. These include: IDCODE, BYPASS, Boundary Scan, APACC, DPACC, and ABORT serial Data Register chains. Each of these Data Registers is discussed in the following sections.
5.4.2.1
IDCODE Data Register The format for the 32-bit IDCODE Data Register defined by the IEEE Standard 1149.1 is shown in Figure 5-3. The standard requires that every JTAG-compliant device implement either the IDCODE instruction or the BYPASS instruction as the default instruction. The LSB of the IDCODE Data Register is defined to be a 1 to distinguish it from the BYPASS instruction, which has an LSB of 0. This allows auto configuration test tools to determine which instruction is the default instruction. The major uses of the JTAG port are for manufacturer testing of component assembly, and program development and debug. To facilitate the use of auto-configuration debug tools, the IDCODE instruction outputs a value of 0x1BA00477. This value indicates an ARM Cortex-M3, Version 1 processor. This allows the debuggers to automatically configure themselves to work correctly with the Cortex-M3 during debug.
Figure 5-3.
31 TDI
IDCODE Register Format
28 27 Part Number 12 11 Manufacturer ID 10 1 TDO
Version
5.4.2.2
BYPASS Data Register The format for the 1-bit BYPASS Data Register defined by the IEEE Standard 1149.1 is shown in Figure 5-4. The standard requires that every JTAG-compliant device implement either the BYPASS instruction or the IDCODE instruction as the default instruction. The LSB of the BYPASS Data Register is defined to be a 0 to distinguish it from the IDCODE instruction, which has an LSB of 1. This allows auto configuration test tools to determine which instruction is the default instruction. Figure 5-4. BYPASS Register Format
0 TDI 0 TDO
5.4.2.3
Boundary Scan Data Register The format of the Boundary Scan Data Register is shown in Figure 5-5. Each GPIO pin, in a counter-clockwise direction from the JTAG port pins, is included in the Boundary Scan Data Register. Each GPIO pin has three associated digital signals that are included in the chain. These
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JTAG Interface
signals are input, output, and output enable, and are arranged in that order as can be seen in the figure. In addition to the GPIO pins, the controller reset pin, RST, is included in the chain. Because the reset pin is always an input, only the input signal is included in the Data Register chain. When the Boundary Scan Data Register is accessed with the SAMPLE/PRELOAD instruction, the input, output, and output enable from each digital pad are sampled and then shifted out of the chain to be verified. The sampling of these values occurs on the rising edge of TCK in the Capture DR state of the TAP controller. While the sampled data is being shifted out of the Boundary Scan chain in the Shift DR state of the TAP controller, new data can be preloaded into the chain for use with the EXTEST and INTEST instructions. These instructions either force data out of the controller, with the EXTEST instruction, or into the controller, with the INTEST instruction. Figure 5-5.
TDI I N
Boundary Scan Register Format
O U T GPIO PB6 O E
...
I N
O U T GPIO m
O E
I N RST
I N
O U T GPIO m+1
O E
...
I N
O U T GPIO n
O TDO E
For detailed information on the order of the input, output, and output enable bits for each of the GPIO ports, please refer to the Stellaris Family Boundary Scan Description Language (BSDL) files, downloadable from www.luminarymicro.com. 5.4.2.4 APACC Data Register The format for the 35-bit APACC Data Register defined by ARM is described in the ARM(R) CortexTM-M3 Technical Reference Manual. 5.4.2.5 DPACC Data Register The format for the 35-bit DPACC Data Register defined by ARM is described in the ARM(R) CortexTM-M3 Technical Reference Manual. 5.4.2.6 ABORT Data Register The format for the 35-bit ABORT Data Register defined by ARM is described in the ARM(R) CortexTM-M3 Technical Reference Manual.
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6
System Control
System control determines the overall operation of the device. It provides information about the device, controls the clocking of the device and individual peripherals, and handles reset detection and reporting.
6.1
Functional Description
The System Control module provides the following capabilities: Device identification, see page 55 Local control, such as reset (see page 55), power (see page 58) and clock control (see page 58) System control (Run, Sleep, and Deep-Sleep modes), see page 60
6.1.1
Device Identification
Seven read-only registers provide software with information on the microcontroller, such as version, part number, SRAM size, Flash size, and other features. See the DID0, DID1 and DC0-DC4 registers starting on page 63.
6.1.2
Reset Control
This section discusses aspects of hardware functions during reset as well as system software requirements following the reset sequence.
6.1.2.1
Reset Sources The controller has six sources of reset: 1. External reset input pin (RST) assertion, see page 55. 2. Power-on reset (POR), see page 56. 3. Internal brown-out (BOR) detector, see page 56. 4. Software-initiated reset (with the software reset registers), see page 57. 5. A watchdog timer reset condition violation, see page 57. 6. Internal low drop-out (LDO) regulator output, see page 58. After a reset, the Reset Cause (RESC) register (see page 82) is set with the reset cause. The bits in this register are sticky and maintain their state across multiple reset sequences, except when an external reset is the cause, and then all the other bits in the RESC register are cleared. Note: The main oscillator is used for external resets and power-on resets; the internal oscillator is used during the internal process by internal reset and clock verification circuitry.
6.1.2.2
RST Pin Assertion The external reset pin (RST) resets the controller. This resets the core and all the peripherals except the JTAG TAP controller (see "JTAG Interface" on page 45). The external reset sequence is as follows: 1. The external reset pin (RST) is asserted and then de-asserted. 2. After RST is de-asserted, the main crystal oscillator must be allowed to settle and there is an internal main oscillator counter that takes from 15-30 ms to account for this. During this time, internal reset to the rest of the controller is held active.
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System Control
3. The internal reset is released and the controller fetches and loads the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. The external reset timing is shown in Figure 19-8 on page 370. 6.1.2.3 Power-On Reset (POR) The Power-On Reset (POR) circuitry detects a rise in power-supply voltage and generates an on-chip reset pulse. To use the on-chip circuitry, the RST input needs a pull-up resistor (1K to 10K ). The device must be operating within the specified operating parameters at the point when the on-chip power-on reset pulse is complete. The specified operating parameters include supply voltage, frequency, temperature, and so on. If the operating conditions are not met at the point of POR end, the Stellaris controller does not operate correctly. In this case, the reset must be extended using external circuitry. The RST input may be used with the circuit as shown in Figure 6-1. Figure 6-1. External Circuitry to Extend Reset
Stellaris D1 R1 RST C1 R2
The R1 and C1 components define the power-on delay. The R2 resistor mitigates any leakage from the RST input. The diode discharges C1 rapidly when the power supply is turned off. The Power-On Reset sequence is as follows: 1. The controller waits for the later of external reset (RST) or internal POR to go inactive. 2. After the resets are inactive, the main crystal oscillator must be allowed to settle and there is an internal main oscillator counter that takes from 15-30 ms to account for this. During this time, internal reset to the rest of the controller is held active. 3. The internal reset is released and the controller fetches and loads the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. The internal POR is only active on the initial power-up of the controller. The Power-On Reset timing is shown in Figure 19-9 on page 370. 6.1.2.4 Brown-Out Reset (BOR) A drop in the input voltage resulting in the assertion of the internal brown-out detector can be used to reset the controller. This is initially disabled and may be enabled by software. The system provides a brown-out detection circuit that triggers if VDD drops below VBTH. The circuit is provided to guard against improper operation of logic and peripherals that operate off VDD and not the LDO voltage. If a brown-out condition is detected, the system may generate a controller interrupt or a system reset. The BOR circuit has a digital filter that protects against noise-related detection. This feature may be optionally enabled.
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Brown-out resets are controlled with the Power-On and Brown-Out Reset Control (PBORCTL) register (see page 73). The BORIOR bit in the PBORCTL register must be set for a brown-out to trigger a reset. The brown-out reset sequence is as follows: 1. When VDD drops below VBTH, an internal BOR condition is set. 2. If the BORWT bit in the PBORCTL register is set, the BOR condition is resampled sometime later (specified by BORTIM) to determine if the original condition was caused by noise. If the BOR condition is not met the second time, then no action is taken. 3. If the BOR condition exists, an internal reset is asserted. 4. The internal reset is released and the controller fetches and loads the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. 5. The internal BOR signal is released after 500 s to prevent another BOR condition from being set before software has a chance to investigate the original cause. The internal Brown-Out Reset timing is shown in Figure 19-10 on page 370. 6.1.2.5 Software Reset Each peripheral can be reset by software. There are three registers that control this function (see the SRCRn registers, starting on page 75). If the bit position corresponding to a peripheral is set, the peripheral is reset. The encoding of the reset registers is consistent with the encoding of the clock gating control for peripherals and on-chip functions (see "System Control" on page 60). Writing a bit lane with a value of 1 initiates a reset of the corresponding unit. Note that all reset signals for all clocks of the specified unit are asserted as a result of a software-initiated reset. The entire system can be reset by software also. Setting the SYSRESETREQ bit in the Cortex-M3 Application Interrupt and Reset Control register resets the entire system including the core. The software-initiated system reset sequence is as follows: 1. A software system reset in initiated by writing the SYSRESETREQ bit in the ARM Cortex-M3 Application Interrupt and Reset Control register. 2. An internal reset is asserted. 3. The internal reset is released and the controller fetches and loads the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. The software-initiated system reset timing is shown in Figure 19-11 on page 370. 6.1.2.6 Watchdog Timer Reset The watchdog timer module's function is to prevent system hangs. The watchdog timer can be configured to generate an interrupt to the controller on its first time-out, and to generate a reset signal on its second time-out. After the first time-out event, the 32-bit counter is reloaded with the value of the Watchdog Timer Load (WDTLOAD) register (see page 187), and the timer resumes counting down from that value. If the timer counts down to its zero state again before the first time-out interrupt is cleared, and the reset signal has been enabled, the watchdog timer asserts its reset signal to the system. The watchdog timer reset sequence is as follows: 1. The watchdog timer times out for the second time without being serviced. 2. An internal reset is asserted.
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3. The internal reset is released and the controller fetches and loads the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. The watchdog reset timing is shown in Figure 19-12 on page 371. 6.1.2.7 Low Drop-Out A reset can be initiated when the internal low drop-out (LDO) regulator output goes unregulated. This is initially disabled and may be enabled by software. LDO is controlled with the LDO Power Control (LDOPCTL) register (see page 74). The LDO reset sequence is as follows: 1. LDO goes unregulated and the LDOARST bit in the LDOARST register is set. 2. An internal reset is asserted. 3. The internal reset is released and the controller fetches and loads the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. The LDO reset timing is shown in Figure 19-13 on page 371.
6.1.3
Power Control
The LDO regulator permits the adjustment of the on-chip output voltage (VOUT). The output may be adjusted in 50 mV increments between the range of 2.25 V through 2.75 V. The adjustment is made through the VADJ field of the LDO Power Control (LDOPCTL) register (see page 74).
6.1.4
6.1.4.1
Clock Control
System control determines the clocking and control of clocks in this part. Fundamental Clock Sources There are two fundamental clock sources for use in the device: The main oscillator, driven from either an external crystal or a single-ended source. As a crystal, the main oscillator source is specified to run from 1-8 MHz. However, when the crystal is being used as the PLL source, it must be from 3.579545-8.192 MHz to meet PLL requirements. As a single-ended source, the range is from DC to the specified speed of the device. The internal oscillator, which is an on-chip free running clock. The internal oscillator is specified to run at 15 MHz 50%. It can be used to clock the system, but the tolerance of frequency range must be met. The internal system clock may be driven by either of the above two reference sources as well as the internal PLL, provided that the PLL input is connected to a clock source that meets its AC requirements. Nearly all of the control for the clocks is provided by the Run-Mode Clock Configuration (RCC) register (see page 83). Figure 6-2 shows the logic for the main clock tree. The peripheral blocks are driven by the System Clock signal and can be programmatically enabled/disabled. The ADC clock signal is automatically divided down to 14-18 MHz for proper ADC operation. The PWM clock signal is a synchronous divide by of the system clock to provide the PWM circuit with more range.
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Figure 6-2.
Main Clock Tree
USESYSDIVa
OSC1 OSC2
Main Osc 1-8 MHz SYSDIVa Internal Osc 15 MHz PLL /4 OSCSRC
a
System Clock
(200 MHz output )
OEN
a
XTALa PWRDNa BYPASS a
PWMDIV
a
PWM Clock
USEPWMDIVa
Constant Divide a. These are bit fields within the Run-Mode Clock Configuration (RCC) register.
(16.667 MHz output )
ADC Clock
6.1.4.2
PLL Frequency Configuration The user does not have direct control over the PLL frequency, but is required to match the external crystal used to an internal PLL-Crystal table. This table is used to create the best fit for PLL parameters to the crystal chosen. Not all crystals result in the PLL operating at exactly 200 MHz, though the frequency is within 1%. The result of the lookup is kept in the XTAL to PLL Translation (PLLCFG) register (see page 88). Table 6-4 on page 87 describes the available crystal choices and default programming of the PLLCFG register. The crystal number is written into the XTAL field of the Run-Mode Clock Configuration (RCC) register (see page 83). Any time the XTAL field changes, a read of the internal table is performed to get the correct value. Table 6-4 on page 87 describes the available crystal choices and default programming values.
6.1.4.3
PLL Modes The PLL has two modes of operation: Normal and Power-Down Normal: The PLL multiplies the input clock reference and drives the output. Power-Down: Most of the PLL internal circuitry is disabled and the PLL does not drive the output. The modes are programmed using the RCC register fields as shown in Table 6-4 on page 87.
6.1.4.4
PLL Operation If the PLL configuration is changed, the PLL output is not stable for a period of time (PLL TREADY=0.5 ms) and during this time, the PLL is not usable as a clock reference. The PLL is changed by one of the following: Change to the XTAL value in the RCC register (see page 83)--writes of the same value do not cause a relock. Change in the PLL from Power-Down to Normal mode. A counter is defined to measure the TREADY requirement. The counter is clocked by the main oscillator. The range of the main oscillator has been taken into account and the down counter is set to 0x1200 (that is, ~600 s at a 8.192-MHz external oscillator clock). Hardware is provided to
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System Control
keep the PLL from being used as a system clock until the TREADY condition is met after one of the two changes above. It is the user's responsibility to have a stable clock source (like the main oscillator) before the RCC register is switched to use the PLL. 6.1.4.5 Clock Verification Timers There are three identical clock verification circuits that can be enabled though software. The circuit checks the faster clock by a slower clock using timers: The main oscillator checks the PLL. The main oscillator checks the internal oscillator. The internal oscillator divided by 64 checks the main oscillator. If the verification timer function is enabled and a failure is detected, the main clock tree is immediately switched to a working clock and an interrupt is generated to the controller. Software can then determine the course of action to take. The actual failure indication and clock switching does not clear without a write to the CLKVCLR register, an external reset, or a POR reset. The clock verification timers are controlled by the PLLVER, IOSCVER, and MOSCVER bits in the RCC register (see page 83).
6.1.5
System Control
For power-savings purposes, the RCGCn, SCGCn, and DCGCn registers control the clock gating logic for each peripheral or block in the system while the controller is in Run, Sleep, and Deep-Sleep mode, respectively. The DC1, DC2 and DC4 registers act as a write mask for the RCGCn, SCGCn, and DCGCn registers. In Run mode, the controller is actively executing code. In Sleep mode, the clocking of the device is unchanged but the controller no longer executes code (and is no longer clocked). In Deep-Sleep mode, the clocking of the device may change (depending on the Run mode clock configuration) and the controller no longer executes code (and is no longer clocked). An interrupt returns the device to Run mode from one of the sleep modes; the sleep modes are entered on request from the code. Each mode is described in more detail in this section.
6.1.5.1
Run Mode Run mode provides normal operation of the processor and all of the peripherals that are currently enabled by the RCGCn registers. The system clock can be any of the available clock sources including the PLL.
6.1.5.2
Sleep Mode In Sleep mode, the Cortex-M3 processor core and the memory subsystem are not clocked. Peripherals are clocked that are enabled in the SCGCn register when Auto Clock Gating is enabled (see RCC register on page 83) or the RCGCn register when the Auto Clock Gating is disabled. The System Clock has the same source and frequency as that during Run mode.
6.1.5.3
Deep-Sleep Mode The Cortex-M3 processor core and the memory subsystem are not clocked. Peripherals are clocked that are enabled in the DCGCn register when Auto Clock Gating is enabled (see RCC register) or the RCGCn register when the Auto Clock Gating is disabled. The system clock source is the main oscillator by default or the internal oscillator specified in the DSLPCLKCFG register if one is enabled (see page 94). When the DSLPCLKCFG register is used, the internal oscillator is powered up, if necessary, and the main oscillator is powered down. If the PLL is running at the time of the WFI instruction, hardware powers the PLL down and overrides the SYSDIV field of the active RCC register to be /16 or /64 respectively. When the Deep-Sleep exit event occurs,
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LM3S317 Data Sheet
hardware brings the system clock back to the source and frequency it had at the onset of Deep-Sleep mode before enabling the clocks that were stopped during the Deep-Sleep duration.
6.2
Initialization and Configuration
The PLL is configured using direct register writes to the Run-Mode Clock Configuration (RCC) register. The steps required to successfully change the PLL-based system clock are: 1. Bypass the PLL and system clock divider by setting the BYPASS bit and clearing the USESYS bit in the RCC register. This configures the system to run off a "raw" clock source (using the main oscillator or internal oscillator) and allows for the new PLL configuration to be validated before switching the system clock to the PLL. 2. Select the crystal value (XTAL) and oscillator source (OSCSRC), and clear the PWRDN and OEN bits in RCC. Setting the XTAL field automatically pulls valid PLL configuration data for the appropriate crystal, and clearing the PWRDN and OEN bits powers and enables the PLL and its output. 3. Select the desired system divider (SYSDIV) and set the USESYS bit in RCC. The SYSDIV field determines the system frequency for the microcontroller. 4. Wait for the PLL to lock by polling the PLLLRIS bit in the Raw Interrupt Status (RIS) register. If the PLL doesn't lock, the configuration is invalid. 5. Enable use of the PLL by clearing the BYPASS bit in RCC. Important: If the BYPASS bit is cleared before the PLL locks, it is possible to render the device unusable.
6.3
Register Map
Table 6-1 lists the System Control registers, grouped by function. The offset listed is a hexadecimal increment to the register's address, relative to the System Control base address of 0x400FE000.
Table 6-1. System Control Register Map
Offset Name Reset Type Description See page
Device Identification and Capabilities 0x000 0x004 0x008 0x010 0x014 0x018 0x01C DID0 DID1 DC0 DC1 DC2 DC3 DC4 0x000F0007 0x001171BF 0x01070011 0x3F3F01FF 0x0000001F RO RO RO RO RO RO RO Device identification 0 Device identification 1 Device capabilities 0 Device capabilities 1 Device capabilities 2 Device Capabilities 3 Device Capabilities 4 63 64 66 67 69 70 72
Local Control 0x030 PBORCTL 0x00007FFD R/W Power-On and Brown-Out Reset Control 73
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System Control
Table 6-1. System Control Register Map (Continued)
Offset 0x034 0x040 0x044 0x048 0x050 0x054 0x058 0x05C 0x060 0x064 Name LDOPCTL SRCR0 SRCR1 SRCR2 RIS IMC MISC RESC RCC PLLCFG Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x078E3AC0 Type R/W R/W R/W R/W RO R/W R/W1C R/W R/W RO Description LDO Power Control Software Reset Control 0 Software Reset Control 1 Software Reset Control 2 Raw Interrupt Status Interrupt Mask Control Masked Interrupt Status and Clear Reset Cause Run-Mode Clock Configuration XTAL to PLL translation See page 74 75 76 77 78 79 81 82 83 88
System Control 0x100 0x104 0x108 0x110 0x114 0x118 0x120 0x124 0x128 0x144 0x150 0x160 RCGC0 RCGC1 RCGC2 SCGC0 SCGC1 SCGC2 DCGC0 DCGC1 DCGC2 DSLPCLKCFG CLKVCLR LDOARST 0x00000000 0x00000000 0x00000000 0x00000001 0x00000000 0x00000000 0x00000001 0x00000000 0x00000000 0x07800000 0x00000000 0x00000000 R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Run-Mode Clock Gating Control 0 Run-Mode Clock Gating Control 1 Run-Mode Clock Gating Control 2 Sleep-Mode Clock Gating Control 0 Sleep-Mode Clock Gating Control 1 Sleep-Mode Clock Gating Control 2 Deep-Sleep-Mode Clock Gating Control 0 Deep-Sleep-Mode Clock Gating Control 1 Deep-Sleep-Mode Clock Gating Control 2 Deep-Sleep Clock Configuration Clock verification clear Allow unregulated LDO to reset the part 89 91 93 89 91 93 89 91 93 94 95 96
6.4
Register Descriptions
The remainder of this section lists and describes the System Control registers, in numerical order by address offset.
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LM3S317 Data Sheet
Register 1: Device Identification 0 (DID0), offset 0x000 This register identifies the version of the device.
Device Identification 0 (DID0)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14
VER
RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7
reserved
RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
MAJOR
Type Reset
RO RO RO RO RO RO RO RO RO RO RO RO -
MINOR
RO RO RO RO -
Bit/Field 31 30:28
Name reserved VER
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This field defines the version of the DID0 register format: 0=Register version for the Stellaris microcontrollers
27:16 15:8
reserved MAJOR
RO RO
0 -
Reserved bits return an indeterminate value, and should never be changed. This field specifies the major revision number of the device. The major revision number is indicated in the part number as a letter (A for first revision, B for second, and so on). This field is encoded as follows: 0: Revision A (initial device) 1: Revision B (first revision) and so on.
7:0
MINOR
RO
-
This field specifies the minor revision number of the device. This field is numeric and is encoded as follows: 0: No changes. Major revision was most recent update. 1: One interconnect change made since last major revision update. 2: Two interconnect changes made since last major revision update. and so on.
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Register 2: Device Identification 1 (DID1), offset 0x004 This register identifies the device family, part number, temperature range, and package type. Note: The bit diagram indicates some values are device-specific. The table below indicates values for your part.
Device Identification 1 (DID1)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
VER
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10
FAM
RO 0 9 RO 0 8 RO 7 RO 6 RO 5
PARTNO
RO 4 RO 3 RO 2 RO 1 RO 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TEMP
RO 0 RO 1 RO 0
PKG
RO 1
RoHS
RO 1 RO -
QUAL
RO -
Bit/Field 31:28
Name VER
Type RO
Reset 0x0
Description This field defines the version of the DID1 register format: 0=Register version for the Stellaris microcontrollers
27:24
FAM
RO
0x0
Family This field provides the family identification of the device within the Luminary Micro product portfolio. The 0x0 value indicates the Stellaris family of microcontrollers.
23:16
PARTNO
RO
0x17
Part Number This field provides the part number of the device within the family. The 0x17 value indicates the LM3S317 microcontroller.
15:8 7:5
reserved TEMP
RO RO
0 1
Reserved bits return an indeterminate value, and should never be changed. Temperature Range This field specifies the temperature rating of the device. A value of 1 indicates the industrial temperature range (-40C to 85C).
4:3 2
PKG RoHS
RO RO
0x1 1
This field specifies the package type. A value of 1 indicates a 48-pin LQFP package. RoHS-Compliance A 1 in this bit specifies the device is RoHS-compliant.
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LM3S317 Data Sheet
Bit/Field 1:0
Name QUAL
Type RO
Reset see table
Description This field specifies the qualification status of the device. This field is encoded as follows: QUAL 00 01 10 11 Description Engineering Sample (unqualified) Pilot Production (unqualified) Fully Qualified Reserved
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System Control
Register 3: Device Capabilities 0 (DC0), offset 0x008 This register is predefined by the part and can be used to verify features. Note: The bit diagram indicates the values are device-specific. The table below indicates values for your specific part.
Device Capabilities Register 0 (DC0)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
SRAMSZ
Type Reset
RO 15 RO 14 RO 13 RO 12 RO 11 RO 10 RO 9 RO 8 RO 7 RO 6 RO 5 RO 4 RO 3 RO 2 RO 1 RO 0
FLSHSZ
Type Reset
RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO -
Bit/Field 31:16 15:0
Name SRAMSZ FLSHSZ
Type RO RO
Reset 0x000F 0x0007
Description Indicates the size of the on-chip SRAM. A value of 0x000F indicates 4 KB of SRAM. Indicates the size of the on-chip flash memory. A value of 0x0007 indicates 16 KB of Flash.
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LM3S317 Data Sheet
Register 4: Device Capabilities 1 (DC1), offset 0x010 This register is predefined by the part and can be used to verify features.
Device Capabilities 1 (DC1)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5
PWM
RO 1 4 RO 0 3
reserved
RO 0 2 RO 0 1
ADC
RO 1 0
MINSYSDIV
Type Reset
RO 0 RO 1 RO 1 RO 1 RO 0
MAXADCSPD
RO 0 RO 0 RO 1
MPU
RO 1
reserved
RO 0
TEMP
RO 1
PLL
RO 1
WDT
RO 1
SWO
RO 1
SWD
RO 1
JTAG
RO 1
Bit/Field 31:21 20 19:17 16 15:12
Name reserved PWMa reserved ADCa MINSYSDIV
Type RO RO RO RO RO
Reset 0 1 0 1 0x07
Description Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the PWM module. Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the ADC module. The reset value is hardware-dependent. A value of 0x7 specifies a 25-MHz clock with a PLL divider of 8. See the RCC register (page 83) for how to change the system clock divisor using the SYSDIV bit. This field indicates the maximum rate at which the ADC samples data. A value of 0x1 indicates 250K samples per second. This bit indicates whether the Memory Protection Unit (MPU) in the Cortex-M3 is available. A 0 in this bit indicates the MPU is not available; a 1 indicates the MPU is available. See the ARM(R) CortexTM-M3 Technical Reference Manual for details on the MPU.
11:8
MAXADCSPDa
RO
0x1
7
MPU
RO
1
6 5 4 3
reserved TEMP PLL WDTa
RO RO RO RO
0 1 1 1
Reserved bits return an indeterminate value, and should never be changed. This bit specifies the presence of an internal temperature sensor. A 1 in this bit indicates the presence of an implemented PLL in the device. A 1 in this bit indicates a watchdog timer on the device.
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System Control
Bit/Field 2 1 0
Name SWOa SWDa JTAGa
Type RO RO RO
Reset 1 1 1
Description A 1 in this bit indicates the presence of the ARM Serial Wire Output (SWO) trace port capabilities. A 1 in this bit indicates the presence of the ARM Serial Wire Debug (SWD) capabilities. A 1 in this bit indicates the presence of a JTAG port.
a. These bits mask the Run-Mode Clock Gating Control 0 (RCGC0) register (see page 113), Sleep-Mode Clock Gating Control 0 (SCGC0) register (see page 113), and Deep-Sleep-Mode Clock Gating Control 0 (DCGC0) register (see page 113). Bits that are not noted are passed as 0. ADCSP is clipped to the maximum value specified in DC1.
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LM3S317 Data Sheet
Register 5: Device Capabilities 2 (DC2), offset 0x014 This register is predefined by the part and can be used to verify features.
Device Capabilities 2 (DC2)
Offset 0x014
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9
COMP0
RO 1 8 RO 0 7 RO 0 6
reserved
RO 0 5 RO 0 4 RO 0 3
GPTM2 GPTM1 GPTM0
RO 1 2 RO 1 1 RO 1 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
SSI
RO 1 RO 0
reserved
RO 0 RO 0
UART0
RO 1
Bit/Field 31:25 24 23:19 18 17 16 15:5 4 3:1 0
Name reserved COMP0 reserved GPTM2 GPTM1 GPTM0 reserved SSI reserved UART0
Type RO RO RO RO RO RO RO RO RO RO
Reset 0 1 0 1 1 1 0 1 0 1
Description Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of analog comparator 0. Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of General-Purpose Timer module 2. A 1 in this bit indicates the presence of General-Purpose Timer module 1. A 1 in this bit indicates the presence of General-Purpose Timer module 0. Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the SSI module. Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the UART0 module.
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System Control
Register 6: Device Capabilities 3 (DC3), offset 0x018 This register is predefined by the part and can be used to verify features.
Device Capabilities 3 (DC3)
Offset 0x018
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14
CCP5
RO 1 13
CCP4
RO 1 12
CCP3
RO 1 11
CCP2
RO 1 10
CCP1
RO 1 9
CCP0
RO 1 8
reserved
RO 0 7 RO 0 6
ADC5
RO 1 5
ADC4
RO 1 4
ADC3
RO 1 3
ADC2
RO 1 2
ADC1
RO 1 1
ADC0
RO 1 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
C0o
RO 1
C0+
RO 1
C0RO 1
PWM5
RO 1
PWM4
RO 1
PWM3
RO 1
PWM2
RO 1
PWM1
RO 1
PWM0
RO 1
Bit/Field 31:30 29 28 27 26 25 24 23:22 21 20 19 18 17 16 15:9 8
Name reserved CCP5 CCP4 CCP3 CCP2 CCP1 CCP0 reserved ADC5 ADC4 ADC3 ADC2 ADC1 ADC0 reserved C0o
Type RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO
Reset 0 1 1 1 1 1 1 0 1 1 1 1 1 1 0 1
Description Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the Capture/ Compare/PWM pin 5. A 1 in this bit indicates the presence of the Capture/ Compare/PWM pin 4. A 1 in this bit indicates the presence of the Capture/ Compare/PWM pin 3. A 1 in this bit indicates the presence of the Capture/ Compare/PWM pin 2. A 1 in this bit indicates the presence of the Capture/ Compare/PWM pin 1. A 1 in this bit indicates the presence of the Capture/ Compare/PWM pin 0. Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the ADC5 pin. A 1 in this bit indicates the presence of the ADC4 pin. A 1 in this bit indicates the presence of the ADC3 pin. A 1 in this bit indicates the presence of the ADC2 pin. A 1 in this bit indicates the presence of the ADC1 pin. A 1 in this bit indicates the presence of the ADC0 pin. Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of the C0o pin.
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LM3S317 Data Sheet
Bit/Field 7 6 5 4 3 2 1 0
Name C0+ C0PWM5 PWM4 PWM3 PWM2 PWM1 PWM0
Type RO RO RO RO RO RO RO RO
Reset 1 1 1 1 1 1 1 1
Description A 1 in this bit indicates the presence of the C0+ pin. A 1 in this bit indicates the presence of the C0- pin. A 1 in this bit indicates the presence of the PWM5 pin. A 1 in this bit indicates the presence of the PWM4 pin. A 1 in this bit indicates the presence of the PWM3 pin. A 1 in this bit indicates the presence of the PWM2 pin. A 1 in this bit indicates the presence of the PWM1 pin. A 1 in this bit indicates the presence of the PWM0 pin.
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System Control
Register 7: Device Capabilities 4 (DC4), offset 0x01C This register is predefined by the part and can be used to verify features.
Device Capabilities 4 (DC4)
Offset 0x01C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PORTE PORTD PORTC PORTB PORTA
RO 1 RO 1 RO 1 RO 1 RO 1
Bit/Field 31:5 4 3 2 1 0
Name reserved PORTE PORTD PORTC PORTB PORTA
Type RO RO RO RO RO RO
Reset 0 1 1 1 1 1
Description Reserved bits return an indeterminate value, and should never be changed. A 1 in this bit indicates the presence of GPIO Port E. A 1 in this bit indicates the presence of GPIO Port D. A 1 in this bit indicates the presence of GPIO Port C. A 1 in this bit indicates the presence of GPIO Port B. A 1 in this bit indicates the presence of GPIO Port A.
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LM3S317 Data Sheet
Register 8: Power-On and Brown-Out Reset Control (PBORCTL), offset 0x030 This register is responsible for controlling reset conditions after initial power-on reset.
Power-On and Brown-Out Reset Control (PBORCTL)
Offset 0x030
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
BORTIM
Type Reset
R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1
BORIOR BORWT
R/W 0 R/W 1
Bit/Field 31:16 15:2
Name reserved BORTIM
Type RO R/W
Reset 0 0x1FFF
Description Reserved bits return an indeterminate value, and should never be changed. This field specifies the number of internal oscillator clocks delayed before the BOR output is resampled if the BORWT bit is set. The width of this field is derived by the tBOR width of 500 s and the internal oscillator (IOSC) frequency of 15 MHz 50%. At +50%, the counter value has to exceed 10,000.
1
BORIOR
R/W
0
BOR Interrupt or Reset This bit controls how a BOR event is signaled to the controller. If set, a reset is signaled. Otherwise, an interrupt is signaled.
0
BORWT
R/W
1
BOR Wait and Check for Noise This bit specifies the response to a brown-out signal assertion. If BORWT is set to 1, the controller waits BORTIM IOSC periods before resampling the BOR output, and if asserted, it signals a BOR condition interrupt or reset. If the BOR resample is deasserted, the cause of the initial assertion was likely noise and the interrupt or reset is suppressed. If BORWT is 0, BOR assertions do not resample the output and any condition is reported immediately if enabled.
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System Control
Register 9: LDO Power Control (LDOPCTL), offset 0x034 The VADJ field in this register adjusts the on-chip output voltage (VOUT).
LDO Power Control (LDOPCTL)
Offset 0x034
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0
VADJ
R/W 0 R/W 0 R/W 0
Bit/Field 31:6 5:0
Name reserved VADJ
Type RO R/W
Reset 0 0x0
Description Reserved bits return an indeterminate value, and should never be changed. This field sets the on-chip output voltage. The programming values for the VADJ field are provided in Table 6-2.
Table 6-2.
VADJ to VOUT
VOUT (V) 2.75 2.70 2.65 2.60 VADJ Value 0x1F 0x00 0x01 0x02 VOUT (V) 2.55 2.50 2.45 2.40 VADJ Value 0x03 0x04 0x05 0x06-0x3F VOUT (V) 2.35 2.30 2.25 Reserved
VADJ Value 0x1B 0x1C 0x1D 0x1E
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LM3S317 Data Sheet
Register 10: Software Reset Control 0 (SRCR0), offset 0x040 Writes to this register are masked by the bits in the Device Capabilities 1 (DC1) register (see page 67).
Software Reset Control 0 (SRCR0)
Offset 0x040
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5
PWM
R/W 0 4 RO 0 3
reserved
RO 0 2 RO 0 1
ADC
R/W 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
WDT
R/W 0 RO 0
reserved
RO 0 RO 0
Bit/Field 31:21 20 19:17 16 15:4 3 2:0
Name reserved PWM reserved ADC reserved WDT reserved
Type RO R/W RO R/W RO R/W RO
Reset 0 0 0 0 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Reset control for the PWM units. Reserved bits return an indeterminate value, and should never be changed. Reset control for the ADC unit. Reserved bits return an indeterminate value, and should never be changed. Reset control for the Watchdog unit. Reserved bits return an indeterminate value, and should never be changed.
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System Control
Register 11: Software Reset Control 1 (SRCR1), offset 0x044 Writes to this register are masked by the bits in the Device Capabilities 2 (DC2) register (see page 69).
Software Reset Control 1 (SRCR1)
Offset 0x044
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9
COMP0
R/W 0 8 RO 0 7 RO 0 6
reserved
RO 0 5 RO 0 4 RO 0 3
GPTM2 GPTM1 GPTM0
R/W 0 2 R/W 0 1 R/W 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
SSI
R/W 0 RO 0
reserved
RO 0 RO 0
UART0
R/W 0
Bit/Field 31:25 24 23:19 18 17 16 15:5 4 3:1 0
Name reserved COMP0 reserved GPTM2 GPTM1 GPTM0 reserved SSI reserved UART0
Type RO R/W RO R/W R/W R/W RO R/W RO R/W
Reset 0 0 0 0 0 0 0 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Reset control for analog comparator 0. Reserved bits return an indeterminate value, and should never be changed. Reset control for General-Purpose Timer module 2. Reset control for General-Purpose Timer module 1. Reset control for General-Purpose Timer module 0. Reserved bits return an indeterminate value, and should never be changed. Reset control for the SSI units. Reserved bits return an indeterminate value, and should never be changed. Reset control for the UART0 module.
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LM3S317 Data Sheet
Register 12: Software Reset Control 2 (SRCR2), offset 0x048 Writes to this register are masked by the bits in the Device Capabilities 4 (DC4) register (see page 72).
Software Reset Control (SRCR2)
Offset 0x048
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PORTE PORTD PORTC PORTB PORTA
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:5 4 3 2 1 0
Name reserved PORTE PORTD PORTC PORTB PORTA
Type RO R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Reset control for GPIO Port E. Reset control for GPIO Port D. Reset control for GPIO Port C. Reset control for GPIO Port B. Reset control for GPIO Port A.
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77
System Control
Register 13: Raw Interrupt Status (RIS), offset 0x050 Central location for system control raw interrupts. These are set and cleared by hardware.
Raw Interrupt Status (RIS)
Offset 0x050
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PLLLRIS CLRIS
RO 0 RO 0
IOFRIS MOFRIS LDORIS BORRIS PLLFRIS
RO 0 RO 0 RO 0 RO 0 RO 0
Bit/Field 31:7 6
Name reserved PLLLRIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. PLL Lock Raw Interrupt Status This bit is set when the PLL TREADY Timer asserts.
5
CLRIS
RO
0
Current Limit Raw Interrupt Status This bit is set if the LDO's CLE output asserts.
4
IOFRIS
RO
0
Internal Oscillator Fault Raw Interrupt Status This bit is set if an internal oscillator fault is detected.
3
MOFRIS
RO
0
Main Oscillator Fault Raw Interrupt Status This bit is set if a main oscillator fault is detected.
2
LDORIS
RO
0
LDO Power Unregulated Raw Interrupt Status This bit is set if a LDO voltage is unregulated.
1
BORRIS
RO
0
Brown-Out Reset Raw Interrupt Status This bit is the raw interrupt status for any brown-out conditions. If set, a brown-out condition was detected. An interrupt is reported if the BORIM bit in the IMC register is set and the BORIOR bit in the PBORCTL register is cleared.
0
PLLFRIS
RO
0
PLL Fault Raw Interrupt Status This bit is set if a PLL fault is detected (stops oscillating).
78 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 14: Interrupt Mask Control (IMC), offset 0x054 Central location for system control interrupt masks.
Interrupt Mask Control (IMC)
Offset 0x054
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PLLLIM
R/W 0
CLIM
R/W 0
IOFIM
R/W 0
MOFIM LDOIM BORIM PLLFIM
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:7 6
Name reserved PLLLIM
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. PLL Lock Interrupt Mask This bit specifies whether a current limit detection is promoted to a controller interrupt. If set, an interrupt is generated if PLLLRIS in RIS is set; otherwise, an interrupt is not generated.
5
CLIM
R/W
0
Current Limit Interrupt Mask This bit specifies whether a current limit detection is promoted to a controller interrupt. If set, an interrupt is generated if CLRIS is set; otherwise, an interrupt is not generated.
4
IOFIM
R/W
0
Internal Oscillator Fault Interrupt Mask This bit specifies whether an internal oscillator fault detection is promoted to a controller interrupt. If set, an interrupt is generated if IOFRIS is set; otherwise, an interrupt is not generated.
3
MOFIM
R/W
0
Main Oscillator Fault Interrupt Mask This bit specifies whether a main oscillator fault detection is promoted to a controller interrupt. If set, an interrupt is generated if MOFRIS is set; otherwise, an interrupt is not generated.
2
LDOIM
R/W
0
LDO Power Unregulated Interrupt Mask This bit specifies whether an LDO unregulated power situation is promoted to a controller interrupt. If set, an interrupt is generated if LDORIS is set; otherwise, an interrupt is not generated.
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System Control
Bit/Field 1
Name BORIM
Type R/W
Reset 0
Description Brown-Out Reset Interrupt Mask This bit specifies whether a brown-out condition is promoted to a controller interrupt. If set, an interrupt is generated if BORRIS is set; otherwise, an interrupt is not generated.
0
PLLFIM
R/W
0
PLL Fault Interrupt Mask This bit specifies whether a PLL fault detection is promoted to a controller interrupt. If set, an interrupt is generated if PLLFRIS is set; otherwise, an interrupt is not generated.
80 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 15: Masked Interrupt Status and Clear (MISC), offset 0x058 Central location for system control result of RIS AND IMC to generate an interrupt to the controller. All of the bits are R/W1C and this action also clears the corresponding raw interrupt bit in the RIS register (see page 78).
Masked Interrupt Status and Clear (MISC)
Offset 0x058
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PLLLMIS CLMIS IOFMIS MOFMIS LDOMIS BORMIS PLLFMIS
R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0
Bit/Field 31:7 6
Name reserved PLLLMIS
Type RO R/W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. PLL Lock Masked Interrupt Status This bit is set when the PLL TREADY timer asserts. The interrupt is cleared by writing a 1 to this bit.
5
CLMIS
R/W1C
0
Current Limit Masked Interrupt Status This bit is set if the LDO's CLE output asserts. The interrupt is cleared by writing a 1 to this bit.
4
IOFMIS
R/W1C
0
Internal Oscillator Fault Masked Interrupt Status This bit is set if an internal oscillator fault is detected. The interrupt is cleared by writing a 1 to this bit.
3
MOFMIS
R/W1C
0
Main Oscillator Fault Masked Interrupt Status This bit is set if a main oscillator fault is detected. The interrupt is cleared by writing a 1 to this bit.
2
LDOMIS
R/W1C
0
LDO Power Unregulated Masked Interrupt Status This bit is set if LDO power is unregulated. The interrupt is cleared by writing a 1 to this bit.
1
BORMIS
R/W1C
0
Brown-Out Reset Masked Interrupt Status This bit is the masked interrupt status for any brown-out conditions. If set, a brown-out condition was detected. An interrupt is reported if the BORIM bit in the IMC register is set and the BORIOR bit in the PBORCTL register is cleared. The interrupt is cleared by writing a 1 to this bit.
0
PLLFMIS
R/W1C
0
PLL Fault Masked Interrupt Status This bit is set if a PLL fault is detected (stops oscillating). The interrupt is cleared by writing a 1 to this bit.
May 4, 2007 Preliminary
81
System Control
Register 16: Reset Cause (RESC), offset 0x05C This field specifies the cause of the reset event to software. The reset value is determined by the cause of the reset. When an external reset is the cause (EXT is set), all other reset bits are cleared. However, if the reset is due to any other cause, the remaining bits are sticky, allowing software to see all causes.
Reset Cause (RESC)
Offset 0x05C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
LDO
R/W -
SW
R/W -
WDT
R/W -
BOR
R/W -
POR
R/W -
EXT
R/W -
Bit/Field 31:6 5 4 3 2 1 0
Name reserved LDO SW WDT BOR POR EXT
Type RO R/W R/W R/W R/W R/W R/W
Reset 0 -
Description Reserved bits return an indeterminate value, and should never be changed. When set to 1, LDO power OK lost is the cause of the reset event. When set to 1, a software reset is the cause of the reset event. When set to 1, a watchdog reset is the cause of the reset event. When set to 1, a brown-out reset is the cause of the reset event. When set to 1, a power-on reset is the cause of the reset event. When set to 1, an external reset (RST assertion) is the cause of the reset event.
82 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 17: Run-Mode Clock Configuration (RCC), offset 0x060 This register is defined to provide source control and frequency speed.
Run-Mode Clock Configuration (RCC)
Offset 0x060
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12
ACG
R/W 0 11 R/W 1 10 R/W 1 9
SYSDIV
R/W 1 8 R/W 1 7
USESYSDIV R/W 0 6
reserved
RO 0 5
USEPWMDIV R/W 0 4 R/W 1 3
PWMDIV
R/W 1 2 R/W 1 1
reserved
RO 0 0
reserved
Type Reset
RO 0 RO 0
PWRDN
R/W 1
OEN
R/W 1
BYPASS
R/W 1
PLLVER
R/W 0 R/W 1 R/W 0
XTAL
R/W 1 R/W 1 R/W 0
OSCSRC
R/W 0
IOSCVER MOSCVER IOSCDIS MOSCDIS
R/W 0 R/W 0 RO 0 RO 0
Bit/Field 31:28 27
Name Reserved ACG
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Auto Clock Gating This bit specifies whether the system uses the Sleep-Mode Clock Gating Control (SCGCn) registers (see page 89) and Deep-Sleep-Mode Clock Gating Control (DCGCn) registers (see page 89) if the controller enters a Sleep or Deep-Sleep mode (respectively). If set, the SCGCn or DCGCn registers are used to control the clocks distributed to the peripherals when the controller is in a sleep mode. Otherwise, the Run-Mode Clock Gating Control (RCGCn) registers (see page 89) are used when the controller enters a sleep mode. The RCGCn registers are always used to control the clocks in Run mode. This allows peripherals to consume less power when the controller is in a sleep mode and the peripheral is unused.
May 4, 2007 Preliminary
83
System Control
Bit/Field 26:23
Name SYSDIV
Type R/W
Reset 0xF
Description System Clock Divisor Specifies which divisor is used to generate the system clock from the PLL output (200 MHz). Binary Value 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Divisor (BYPASS=1) reserved /2 /3 /4 /5 /6 /7 /8 /9 /10 /11 /12 /13 /14 /15 /16 Frequency (BYPASS=0) reserved reserved reserved reserved reserved reserved reserved 25 MHz 22.22 MHz 20 MHz 18.18 MHz 16.67 MHz 15.38 MHz 14.29 MHz 13.33 MHz 12.5 MHz (default)
When reading the Run-Mode Clock Configuration (RCC) register (see page 83), the SYSDIV value is MINSYSDIV if a lower divider was requested and the PLL is being used. This lower value is allowed to divide a non-PLL source. 22 USESYSDIV R/W 0 Use the system clock divider as the source for the system clock. The system clock divider is forced to be used when the PLL is selected as the source. Reserved bits return an indeterminate value, and should never be changed. Use the PWM clock divider as the source for the PWM clock.
21 20
reserved USEPWMDIV
RO R/W
0 0
84 Preliminary
May 4, 2007
LM3S317 Data Sheet
Bit/Field 19:17
Name PWMDIV
Type R/W
Reset 0x7
Description PWM Unit Clock Divisor This field specifies the binary divisor used to predivide the system clock down for use as the timing reference for the PWM module. This clock is only power 2 divide and rising edge is synchronous without phase shift from the system clock. Value 000 001 010 011 100 101 110 111 Divisor /2 /4 /8 /16 /32 /64 /64 /64 (default)
16:14 13
reserved PWRDN
RO R/W
0 1
Reserved bits return an indeterminate value, and should never be changed. PLL Power Down This bit connects to the PLL PWRDN input. The reset value of 1 powers down the PLL. See Table 6-4 on page 87 for PLL mode control.
12
OEN
R/W
1
PLL Output Enable This bit specifies whether the PLL output driver is enabled. If cleared, the driver transmits the PLL clock to the output. Otherwise, the PLL clock does not oscillate outside the PLL module. Note: Both PWRDN and OEN must be cleared to run the PLL.
11
BYPASS
R/W
1
PLL Bypass Chooses whether the system clock is derived from the PLL output or the OSC source. If set, the clock that drives the system is the OSC source. Otherwise, the clock that drives the system is the PLL output clock divided by the system divider. Note: The ADC module must be clocked from the PLL or directly from a 14-MHz to an 18-MHz clock source in order to operate properly.
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85
System Control
Bit/Field 10
Name PLLVER
Type R/W
Reset 0
Description PLL Verification This bit controls the PLL verification timer function. If set, the verification timer is enabled and an interrupt is generated if the PLL becomes inoperative. Otherwise, the verification timer is not enabled.
9:6
XTAL
R/W
0xB
This field specifies the crystal value attached to the main oscillator. The encoding for this field is provided in Table 6-4 on page 87.
Oscillator-Related Bits 5:4 OSCSRC R/W 0x0 Picks among the four input sources for the OSC. The values are: Value 00 01 10 11 3 IOSCVER R/W 0 Input Source Main oscillator (default) Internal oscillator Internal oscillator / 4 (this is necessary if used as input to PLL) reserved
This bit controls the internal oscillator verification timer function. If set, the verification timer is enabled and an interrupt is generated if the timer becomes inoperative. Otherwise, the verification timer is not enabled. This bit controls the main oscillator verification timer function. If set, the verification timer is enabled and an interrupt is generated if the timer becomes inoperative. Otherwise, the verification timer is not enabled. Internal Oscillator Disable 0: Internal oscillator is enabled. 1: Internal oscillator is disabled.
2
MOSCVER
R/W
0
1
IOSCDIS
R/W
0
0
MOSCDIS
R/W
0
Main Oscillator Disable 0: Main oscillator is enabled. 1: Main oscillator is disabled.
Table 6-3.
PWRDN 1 0
PLL Mode Control
OEN X 0 Mode Power down Normal
86 Preliminary
May 4, 2007
LM3S317 Data Sheet
Table 6-4.
Default Crystal Field Values and PLL Programming
Crystal Frequency (MHz) reserved 3.579545 MHz 3.6864 MHz 4 MHz 4.096 MHz 4.9152 MHz 5 MHz 5.12 MHz 6 MHz (reset value) 6.144 MHz 7.3728 MHz 8 MHz 8.192 MHz
Crystal Number (XTAL Binary Value) 0000-0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111
May 4, 2007 Preliminary
87
System Control
Register 18: XTAL to PLL Translation (PLLCFG), offset 0x064 This register provides a means of translating external crystal frequencies into the appropriate PLL settings. This register is initialized during the reset sequence and updated anytime that the XTAL field changes in the Run-Mode Clock Configuration (RCC) register (see page 83).
XTAL to PLL Translation (PLLCFG)
Offset 0x064
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
OD
Type Reset
RO RO RO RO RO RO -
F
RO RO RO RO RO RO RO -
R
RO RO RO -
Bit/Field 31:16 15:14 13:5 4:0
Name reserved OD F R
Type RO RO RO RO
Reset 0 -
Description Reserved bits return an indeterminate value, and should never be changed. This field specifies the value supplied to the PLL's OD input. This field specifies the value supplied to the PLL's F input. This field specifies the value supplied to the PLL's R input.
88 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 19: Run-Mode Clock Gating Control 0 (RCGC0), offset 0x100 Register 20: Sleep-Mode Clock Gating Control 0 (SCGC0), offset 0x110 Register 21: Deep-Sleep-Mode Clock Gating Control 0 (DCGC0), offset 0x120 These registers control the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC0 is the clock configuration register for running operation, SCGC0 for Sleep operation, and DCGC0 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register (see page 83) specifies that the system uses sleep modes.
Run-Mode, Sleep-Mode and Deep-Sleep-Mode Clock Gating Control 0 (RCGC0, SCG0, and DCGC0)
Offset 0x100, 0x110, 0x120
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5
PWM
R/W 0 4 RO 0 3
reserved
RO 0 2 RO 0 1
ADC
R/W 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 R/W 0
MAXADCSPD
R/W 0 R/W 0 R/W 0 RO 0
reserved
RO 0 RO 0 RO 0
WDT
R/W 0 RO 0
reserved
RO 0 RO 0
Bit/Field 31:21 20
Name reserved PWM
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the PWM module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the ADC module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a Reserved bits return an indeterminate value, and should never be changed.
19:17 16
reserved ADC
RO R/W
0 0
15:12
reserved
RO
0
May 4, 2007 Preliminary
89
System Control
Bit/Field 11:8
Name MAXADCSPD
Type R/W
Reset 0x0
Description This field sets the rate at which the ADC samples data. You can set the sample rate by setting the MAXADCSPD bit as follows (you cannot set the rate higher than the maximum rate.): Value 0x0 0x1 Sample Rate 125K samples/second 250K samples/second
7:4 3
reserved WDT
RO R/W
0 0
Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the WDT module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a Reserved bits return an indeterminate value, and should never be changed.
2:0
a.
reserved
RO
0
If the unit is unclocked, a read or write to the unit generates a bus fault.
90 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 22: Run-Mode Clock Gating Control 1 (RCGC1), offset 0x104 Register 23: Sleep-Mode Clock Gating Control 1 (SCGC1), offset 0x114 Register 24: Deep-Sleep-Mode Clock Gating Control 1 (DCGC1), offset 0x124 These registers control the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC1 is the clock configuration register for running operation, SCGC1 for Sleep operation, and DCGC1 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register (see page 83) specifies that the system uses sleep modes.
Run-Mode, Sleep-Mode, and Deep-Sleep-Mode Clock Gating Control 1 (RCGC1, SCGC1, and DCGC1)
Offset 0x104, 0x114, and 0x124
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9
COMP0
R/W 0 8 RO 0 7 RO 0 6
reserved
RO 0 5 RO 0 4 RO 0 3
GPTM2 GPTM1 GPTM0
R/W 0 2 R/W 0 1 R/W 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
SSI
R/W 0 RO 0
reserved
RO 0 RO 0
UART0
R/W 0
Bit/Field 31:25 24
Name reserved COMP0
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the Comparator 0 module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the General Purpose Timer 2 module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a This bit controls the clock gating for the General Purpose Timer 1 module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a This bit controls the clock gating for the General Purpose Timer 0 module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a
23:19 18
reserved GPTM2
RO R/W
0 0
17
GPTM1
R/W
0
16
GPTM0
R/W
0
May 4, 2007 Preliminary
91
System Control
Bit/Field 15:5 4
Name reserved SSI
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the SSI module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the UART0 module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a
3:1 0
reserved UART0
RO R/W
0 0
a.
If the unit is unclocked, reads or writes to the unit will generate a bus fault.
92 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 25: Run-Mode Clock Gating Control 2 (RCGC2), offset 0x108 Register 26: Sleep-Mode Clock Gating Control 2 (SCGC2), offset 0x118 Register 27: Deep-Sleep-Mode Clock Gating Control 2 (DCGC2), offset 0x128 These registers control the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC2 is the clock configuration register for running operation, SCGC2 for Sleep operation, and DCGC2 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register (see page 83) specifies that the system uses sleep modes.
Run-Mode, Sleep-Mode, and Deep-Sleep-Mode Clock Gating Control 2 (RCGC2, SCGC2, and DCGC2)
Offset 0x108, 0x118, and 0x128
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PORTE PORTD PORTC PORTB PORTA
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:5 4
Name reserved PORTE
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit controls the clock gating for the GPIO Port E module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a This bit controls the clock gating for the GPIO Port D module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a This bit controls the clock gating for the GPIO Port C module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a This bit controls the clock gating for the GPIO Port B module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a This bit controls the clock gating for the GPIO Port A module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled.a
3
PORTD
R/W
0
2
PORTC
R/W
0
1
PORTB
R/W
0
0
PORTA
R/W
0
a.
If the unit is unclocked, reads or writes to the unit will generate a bus fault.
May 4, 2007 Preliminary
93
System Control
Register 28: Deep-Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 This register is used to automatically switch from the main oscillator to the internal oscillator when entering Deep-Sleep mode. The system clock source is the main oscillator by default. When this register is set, the internal oscillator is powered up and the main oscillator is powered down. When the Deep-Sleep exit event occurs, hardware brings the system clock back to the source and frequency it had at the onset of Deep-Sleep mode.
Deep-Sleep Clock Configuration (DSLPCLKCFG)
Offset 0x144
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IOSC
R/W 0
Bit/Field 31:1 0
Name Reserved IOSC
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This field allows an override of the main oscillator when Deep-Sleep mode is running. When set, this field forces the internal oscillator to be the clock source during Deep-Sleep mode. Otherwise, the main oscillator remains as the default system clock source.
94 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 29: Clock Verification Clear (CLKVCLR), offset 0x150 This register is provided as a means of clearing the clock verification circuits by software. Since the clock verification circuits force a known good clock to control the process, the controller is allowed the opportunity to solve the problem and clear the verification fault. This register clears all clock verification faults. To clear a clock verification fault, the VERCLR bit must be set and then cleared by software. This bit is not self-clearing.
Clock Verification Clear (CLKVCLR)
Offset 0x150
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
VERCLR
R/W 0
Bit/Field 31:1 0
Name Reserved VERCLR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Clear clock verification faults.
May 4, 2007 Preliminary
95
System Control
Register 30: Allow Unregulated LDO to Reset the Part (LDOARST), offset 0x160 This register is provided as a means of allowing the LDO to reset the part if the voltage goes unregulated. Use this register to choose whether to automatically reset the part if the LDO goes unregulated, based on the design tolerance for LDO fluctuation.
Allow Unregulated LDO to Reset the Part (LDOARST)
Offset 0x160
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
LDOARST
R/W 0
Bit/Field 31:1 0
Name Reserved LDOARST
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Set to 1 to allow unregulated LDO output to reset the part.
96 Preliminary
May 4, 2007
LM3S317 Data Sheet
7
Internal Memory
The LM3S317 microcontroller comes with 4 KB of bit-banded SRAM and 16 KB of flash memory. The flash controller provides a user-friendly interface, making flash programming a simple task. Flash protection can be applied to the flash memory on a 2-KB block basis.
7.1
Figure 7-1.
Block Diagram
Flash Block Diagram
Flash Timing USECRL
Flash Control ICode Cortex-M3 DCode FMA FMD FMC System Bus FCRIS FCIM FCMISC Bridge APB Flash Array
Flash Protection FMPRE SRAM Array FMPPE
7.2
7.2.1
Functional Description
This section describes the functionality of both memories.
SRAM Memory
The internal SRAM of the Stellaris devices is located at address 0x20000000 of the device memory map. To reduce the number of time consuming read-modify-write (RMW) operations, ARM has introduced bit-banding technology in the new Cortex-M3 processor. With a bit-band-enabled processor, certain regions in the memory map (SRAM and peripheral space) can use address aliases to access individual bits in a single, atomic operation.
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Internal Memory
The bit-band alias is calculated by using the formula:
bit-band alias = bit-band base + (byte offset * 32) + (bit number * 4)
For example, if bit 3 at address 0x20001000 is to be modified, the bit-band alias is calculated as:
0x22000000 + (0x1000 * 32) + (3 * 4) = 0x2202000C
With the alias address calculated, an instruction performing a read/write to address 0x2202000C allows direct access to only bit 3 of the byte at address 0x20001000. For details about bit-banding, please refer to Chapter 4, "Memory Map" in the ARM(R) CortexTM-M3 Technical Reference Manual.
7.2.2
Flash Memory
The flash is organized as a set of 1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the block to be reset to all 1s. These blocks are paired into a set of 2-KB blocks that can be individually protected. The blocks can be marked as read-only or execute-only, providing different levels of code protection. Read-only blocks cannot be erased or programmed, protecting the contents of those blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only be read by the controller instruction fetch mechanism, protecting the contents of those blocks from being read by either the controller or by a debugger.
7.2.2.1
Flash Memory Timing The timing for the flash is automatically handled by the flash controller. However, in order to do so, it must know the clock rate of the system in order to time its internal signals properly. The number of clock cycles per microsecond must be provided to the flash controller for it to accomplish this timing. It is software's responsibility to keep the flash controller updated with this information via the USec Reload (USECRL) register (see page 105). On reset, USECRL is loaded with a value that configures the flash timing so that it works with the default crystal value of 6 MHz. If software changes the system operating frequency, the new operating frequency must be loaded into USECRL before any flash modifications are attempted. For example, if the device is operating at a speed of 20 MHz, a value of 0x13 must be written to the USECRL register.
7.2.2.2
Flash Memory Protection The user is provided two forms of flash protection per 2-KB flash blocks in two 32-bit wide registers. The protection policy for each form is controlled by individual bits (per policy per block) in the FMPPE (see page 104) and FMPRE registers (see page 103). Flash Memory Protection Program Enable (FMPPE[Blockn:Block0]): If set, the block may be programmed (written) or erased. If cleared, the block may not be changed. Flash Memory Protection Read Enable (FMPRE[Blockn:Block0]): If set, the block may be executed or read by software or debuggers. If cleared, the block may only be executed. The contents of the memory block are prohibited from being accessed as data and traversing the DCode bus.
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LM3S317 Data Sheet
The policies may be combined as shown in Table 7-1. Table 7-1.
FMPPE 0 1 0
Flash Protection Policy Combinations
FMPRE 0 0 1 Protection Execute-only protection. The block may only be executed and may not be written or erased. This mode is used to protect code. The block may be written, erased, or executed, but not read. This combination is unlikely to be used. Read-only protection. The block may be read or executed but may not be written or erased. This mode is used to lock the block from further modification while allowing any read or execute access. No protection. The block may be written, erased, executed, or read.
1
1
An access that attempts to program or erase a PE-protected block is prohibited. A controller interrupt may be optionally generated (by setting the AMASK bit in the FIM register) to alert software developers of poorly behaving software during the development and debug phases. An access that attempts to read an RE-protected block is prohibited. Such accesses return data filled with all 0s. A controller interrupt may be optionally generated to alert software developers of poorly behaving software during the development and debug phases. The factory settings for the FMPRE and FMPPE registers are a value of 1 for all implemented banks. This implements a policy of open access and programmability. The register bits may be changed by writing the specific register bit. The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. 7.2.2.3 Flash Protection by Disabling Debug Access Flash memory may also be protected by permanently disabling access to the Debug Access Port (DAP) through the JTAG and SWD interfaces. This is accomplished by clearing the DBG field of the FMPRE register. Flash Memory Protection Read Enable (DBG field): If set to 0x2, access to the DAP is enabled through the JTAG and SWD interfaces. If clear, access to the DAP is disabled. The DBG field programming becomes permanent, and irreversible, after a commit sequence is performed. In the initial state, provided from the factory, access is enabled in order to facilitate code development and debug. Access to the DAP may be disabled at the end of the manufacturing flow, once all tests have passed and software loaded. This change will not take effect until the next power-up of the device. Note that it is recommended that disabling access to the DAP be combined with a mechanism for providing end-user installable updates (if necessary) such as the Stellaris boot loader. Important: Once the DBG field is cleared and committed, this field can never be restored to the factory-programmed value--which means JTAG/SWD interface to the debug module can never be re-enabled. This sequence does NOT disable the JTAG controller, it only disables the access of the DAP through the JTAG or SWD interfaces. The JTAG interface remains functional and access to the Test Access Port remains enabled, allowing the user to execute the IEEE JTAG-defined instructions (for example, to perform boundary scan operations).
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Internal Memory
If the user will also be using the FMPRE bits to protect flash memory from being read as data (to mark sets of 2 KB blocks of flash memory as execute-only), these one-time-programmable bits should be written at the same time that the debug disable bits are programmed. Mechanisms to execute the one-time code sequence to disable all debug access include: Selecting the debug disable option in the Stellaris boot loader Loading the debug disable sequence into SRAM and running it once from SRAM after programming the final end application code into flash 7.2.2.4 Flash Memory Programming Writing the flash memory requires that the code be executed out of SRAM to avoid corrupting or interrupting the bus timing. Flash pages can be erased on a page basis (1 KB in size), or by performing a mass erase of the entire flash. All erase and program operations are performed using the Flash Memory Address (FMA), Flash Memory Data (FMD) and Flash Memory Control (FMC) registers. See section 7.3 for examples.
7.3
Initialization and Configuration
This section shows examples for using the flash controller to perform various operations on the contents of the flash memory.
7.3.1
Changing Flash Protection Bits
As discussed in Section 7.2.2.2, changes to the protection bits must be committed before they take effect. The sequence below is used change and commit a block protection bit in the FMPRE or FMPPE registers. The sequence to change and commit a bit in software is as follows: 1. The Flash Memory Protection Read Enable (FMPRE) and Flash Memory Protection Program Enable (FMPPE) registers are written, changing the intended bit(s). The action of these changes can be tested by software while in this state. 2. The Flash Memory Address (FMA) register (see page 106) bit 0 is set to 1 if the FMPPE register is to be committed; otherwise, a 0 commits the FMPRE register. 3. The Flash Memory Control (FMC) register (see page 109) is written with the COMT bit set. This initiates a write sequence and commits the changes. There is a special sequence to change and commit the DBG bits in the Flash Memory Protection Read Enable (FMPRE) register. This sequence also sets and commits any changes from 1 to 0 in the block protection bits (for execute-only) in the FMPRE register. 1. 1. The Flash Memory Protection Read Enable (FMPRE) register is written, changing the intended bit(s). The action of these changes can be tested by software while in this state. 2. 2. The Flash Memory Address (FMA) register (see page 102) is written with a value of 0x900. 3. 3. The Flash Memory Control (FMC) register (see page 104) is written with the COMT bit set. This initiates a write sequence and commits the changes. Below is an example code sequence to permanently disable the JTAG and SWD interface to the debug module using Luminary Micro's DriverLib peripheral driver library:
#include "hw_types.h" #include "hw_flash.h" void permanently_disable_jtag_swd(void) {
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LM3S317 Data Sheet
// // Clear the DBG field of the FMPRE register. Note that the value // used in this instance does not affect the state of the BlockN // bits, but were the value different, all bits in the FMPRE are // affected by this function! // HWREG(FLASH_FMPRE) &= 0x3fffffff; // // The following sequence activates the one-time // programming of the FMPRE register. // HWREG(FLASH_FMA) = 0x900; HWREG(FLASH_FMC) = (FLASH_FMC_WRKEY | FLASH_FMC_COMT); // // Wait until the operation is complete. // while (HWREG(FLASH_FMC) & FLASH_FMC_COMT) { } }
7.3.2
Flash Programming
The Stellaris devices provide a user-friendly interface for flash programming. All erase/program operations are handled via three registers: FMA, FMD and FMC. The flash is programmed using the following sequence: 1. Write source data to the FMD register. 2. Write the target address to the FMA register. 3. Write the flash write key and the WRITE bit (a value of 0xA4420001) to the FMC register. 4. Poll the FMC register until the WRITE bit is cleared. To perform an erase of a 1-KB page: 1. Write the page address to the FMA register. 2. Write the flash write key and the ERASE bit (a value of 0xA4420002) to the FMC register. 3. Poll the FMC register until the ERASE bit is cleared. To perform a mass erase of the flash: 1. Write the flash write key and the MERASE bit (a value of 0xA4420004) to the FMC register. 2. Poll the FMC register until the MERASE bit is cleared.
7.4
Register Map
Table 7-2 lists the Flash memory and control registers. The offset listed is a hexadecimal increment to the register's address, relative to the Flash control base address of 0x400FD000,
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Internal Memory
except for FMPRE and FMPPE, which are relative to the System Control base address of 0x400FE000. Table 7-2. Flash Register Map
Offset 0x130a 0x134a 0X140a 0x000 0x004 0x008 0x00C 0x010 0x014 Name FMPRE FMPPE USECRL FMA FMD FMC FCRIS FCIM FCMISC Reset 0x000000FF 0x000000FF 0x00000018 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 Type R/W0 R/W0 R/W R/W R/W R/W RO R/W R/W1C Description Flash memory read protect Flash memory program protect USec reload Flash memory address Flash memory data Flash memory control Flash controller raw interrupt status Flash controller interrupt mask Flash controller masked interrupt status and clear See page 103 104 105 106 108 109 111 112 113
a. Relative to System Control base address of 0x400FE000.
7.5
Register Descriptions
The remainder of this section lists and describes the Flash Memory registers, in numerical order by address offset.
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LM3S317 Data Sheet
Register 1: Flash Memory Protection Read Enable (FMPRE), offset 0x130 Note: Offset is relative to System Control base address of 0x400FE000 This register stores the read-only (FMPRE) protection bits for each 2-KB flash block and bits to disable debug access through JTAG and SWD. This register is loaded during the power-on reset sequence. The factory setting for the FMPRE register is a value of 1 for all implemented flash banks and 0x2 for the DBG field. These bits implement a policy of open access, programmability, and debug access. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see "Flash Memory Protection" on page 87.
Flash Memory Protection Read Enable (FMPRE)
Offset 0x130 and 0x134
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
DBG
Type Reset
R/W0 1 15 R/W0 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9
reserved
RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
Block7
R/W0 1
Block6
R/W0 1
Block5
R/W0 1
Block4
R/W0 1
Block3
R/W0 1
Block2
R/W0 1
Block1
R/W0 1
Block0
R/W0 1
Bit/Field 31:30
Name DBG
Type R/W0
Reset 0x2
Description Controls access to the debug access port (DAP) through the JTAG and SWD interfaces. A value of 0x2 enables access. A value of 0 disables access. Reserved bits return an indeterminate value, and should never be changed. Enable 2-KB flash blocks to be executed or read. The policies may be combined as shown in Table Table 7-1 on page 99.
29:8 7:0
reserved Block7Block0
RO R/W0
0 0xFF
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Internal Memory
Register 2: Flash Memory Protection Program Enable (FMPPE), offset 0x134 Note: Offset is relative to System Control base address of 0x400FE000 This register stores the execute-only (FMPPE) protection bits for each 2-KB flash block. This register is loaded during the power-on reset sequence. The factory setting for the FMPPE register is a value of 1 for all implemented banks. This implements a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see "Flash Memory Protection" on page 98.
Flash Memory Protection Program Enable (FMPPE)
Offset 0x130 and 0x134
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
Block7
R/W0 1
Block6
R/W0 1
Block5
R/W0 1
Block4
R/W0 1
Block3
R/W0 1
Block2
R/W0 1
Block1
R/W0 1
Block0
R/W0 1
Bit/Field 31:8 7:0
Name reserved Block7Block0
Type RO R/W0
Reset 0 1
Description Reserved bits return an indeterminate value, and should never be changed. Enable 2-KB flash blocks to be written or erased (FMPPE register). This policy may be combined with the FMPRE register as shown in Table 7-1 on page 99.
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LM3S317 Data Sheet
Register 3: USec Reload (USECRL), offset 0x140 Note: Offset is relative to System Control base address of 0x400FE000 This register is provided as a means of creating a 1-s tick divider reload value for the flash controller. The internal flash has specific minimum and maximum requirements on the length of time the high voltage write pulse can be applied. It is required that this register contain the operating frequency (in MHz -1) whenever the flash is being erased or programmed. The user is required to change this value if the clocking conditions are changed for a flash erase/program operation.
Usec Reload (USECRL)
Offset 0x140
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0
USEC
R/W 1 R/W 1 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved USEC
Type RO R/W
Reset 0 0x18
Description Reserved bits return an indeterminate value, and should never be changed. MHz -1 of the controller clock when the flash is being erased or programmed. USEC should be set to 0x18 (24 MHz) whenever the flash is being erased or programmed.
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105
Internal Memory
Register 4: Flash Memory Address (FMA), offset 0x000 During a write operation, this register contains a 4-byte-aligned address and specifies where the data is written. During erase operations, this register contains a 1 KB-aligned address and
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LM3S317 Data Sheet
specifies which page is erased. Note that the alignment requirements must be met by software or the results of the operation are unpredictable.
Flash Memory Address (FMA)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
OFFSET
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Flash Memory Address (FMA)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
OFFSET
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Flash Memory Address (FMA)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
OFFSET
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Flash Memory Address (FMA)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
OFFSET
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:14 13:0
Name reserved OFFSET
Type RO R/W
Reset 0x0 0x0
Description Reserved bits return an indeterminate value, and should never be changed. Address offset in flash where operation is performed.
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Internal Memory
Register 5: Flash Memory Data (FMD), offset 0x004 This register contains the data to be written during the programming cycle or read during the read cycle. Note that the contents of this register are undefined for a read access of an execute-only block. This register is not used during the erase cycles.
Flash Memory Data (FMD)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
DATA
Type Reset
R/W 0 15 R/W 0 14 R/W 0 13 R/W 0 12 R/W 0 11 R/W 0 10 R/W 0 9 R/W 0 8 R/W 0 7 R/W 0 6 R/W 0 5 R/W 0 4 R/W 0 3 R/W 0 2 R/W 0 1 R/W 0 0
DATA
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:0
Name DATA
Type R/W
Reset 0x0
Description Data value for write operation.
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LM3S317 Data Sheet
Register 6: Flash Memory Control (FMC), offset 0x008 When this register is written, the flash controller initiates the appropriate access cycle for the location specified by the Flash Memory Address (FMA) register (see page 106). If the access is a write access, the data contained in the Flash Memory Data (FMD) register (see page 108) is written. This is the final register written and initiates the memory operation. There are four control bits in the lower byte of this register that, when set, initiate the memory operation. The most used of these register bits are the ERASE and WRITE bits. It is a programming error to write multiple control bits and the results of such an operation are unpredictable.
Flash Memory Control (FMC)
Offset 0x008
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
WRKEY
Type Reset
WO 0 15 WO 0 14 WO 0 13 WO 0 12 WO 0 11 WO 0 10 WO 0 9 WO 0 8 WO 0 7 WO 0 6 WO 0 5 WO 0 4 WO 0 3 WO 0 2 WO 0 1 WO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
COMT MERASE ERASE WRITE
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16
Name WRKEY
Type WO
Reset 0x0
Description This field contains a write key, which is used to minimize the incidence of accidental flash writes. The value 0xA442 must be written into this field for a write to occur. Writes to the FMC register without this WRKEY value are ignored. A read of this field returns the value 0. Reserved bits return an indeterminate value, and should never be changed. Commit (write) of register value to nonvolatile storage. A write of 0 has no effect on the state of this bit. If read, the state of the previous commit access is provided. If the previous commit access is complete, a 0 is returned; otherwise, if the commit access is not complete, a 1 is returned. This can take up to 50 s.
15:4 3
reserved COMT
RO R/W
0 0
2
MERASE
R/W
0
Mass erase flash memory If this bit is set, the flash main memory of the device is all erased. A write of 0 has no effect on the state of this bit. If read, the state of the previous mass erase access is provided. If the previous mass erase access is complete, a 0 is returned; otherwise, if the previous mass erase access is not complete, a 1 is returned. This can take up to 250 ms.
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Internal Memory
Bit/Field 1
Name ERASE
Type R/W
Reset 0
Description Erase a page of flash memory If this bit is set, the page of flash main memory as specified by the contents of FMA is erased. A write of 0 has no effect on the state of this bit. If read, the state of the previous erase access is provided. If the previous erase access is complete, a 0 is returned; otherwise, if the previous erase access is not complete, a 1 is returned. This can take up to 25 ms.
0
WRITE
R/W
0
Write a word into flash memory If this bit is set, the data stored in FMD is written into the location as specified by the contents of FMA. A write of 0 has no effect on the state of this bit. If read, the state of the previous write update is provided. If the previous write access is complete, a 0 is returned; otherwise, if the write access is not complete, a 1 is returned. This can take up to 50 s.
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LM3S317 Data Sheet
Register 7: Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C This register indicates that the flash controller has an interrupt condition. An interrupt is only signaled if the corresponding FCIM register bit is set.
Flash Controller Raw Interrupt Status (FCRIS)
Offset 0x00C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PRIS
RO 0
ARIS
RO 0
Bit/Field 31:2 1
Name reserved PRIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Programming Raw Interrupt Status This bit indicates the current state of the programming cycle. If set, the programming cycle completed; if cleared, the programming cycle has not completed. Programming cycles are either write or erase actions generated through the Flash Memory Control (FMC) register bits (see page 109).
0
ARIS
RO
0
Access Raw Interrupt Status This bit indicates if the flash was improperly accessed. If set, the program tried to access the flash counter to the policy as set in the Flash Memory Protection Read Enable (FMPRE) and Flash Memory Protection Program Enable (FMPPE) registers (see page 103). Otherwise, no access has tried to improperly access the flash.
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Internal Memory
Register 8: Flash Controller Interrupt Mask (FCIM), offset 0x010 This register controls whether the flash controller generates interrupts to the controller.
Flash Controller Interrupt Mask (FCIM)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PMASK AMASK
R/W 0 R/W 0
Bit/Field 31:2 1
Name reserved PMASK
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Programming Interrupt Mask This bit controls the reporting of the programming raw interrupt status to the controller. If set, a programming-generated interrupt is promoted to the controller. Otherwise, interrupts are recorded but suppressed from the controller.
0
AMASK
R/W
0
Access Interrupt Mask This bit controls the reporting of the access raw interrupt status to the controller. If set, an access-generated interrupt is promoted to the controller. Otherwise, interrupts are recorded but suppressed from the controller.
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LM3S317 Data Sheet
Register 9: Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014 This register provides two functions. First, it reports the cause of an interrupt by indicating which interrupt source or sources are signaling the interrupt. Second, it serves as the method to clear the interrupt reporting.
Flash Controller Masked Interrupt Status and Clear (FCMISC)
Offset 0x014
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PMISC
R/W1C 0
AMISC
R/W1C 0
Bit/Field 31:2 1
Name reserved PMISC
Type RO R/W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Programming Masked Interrupt Status and Clear This bit indicates whether an interrupt was signaled because a programming cycle completed and was not masked. This bit is cleared by writing a 1. The PRIS bit in the FCRIS register (see page 111) is also cleared when the PMISC bit is cleared.
0
AMISC
R/W1C
0
Access Masked Interrupt Status and Clear This bit indicates whether an interrupt was signaled because an improper access was attempted and was not masked. This bit is cleared by writing a 1. The ARIS bit in the FCRIS register is also cleared when the AMISC bit is cleared.
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General-Purpose Input/Outputs (GPIOs)
8
General-Purpose Input/Outputs (GPIOs)
The GPIO module is composed of five physical GPIO blocks, each corresponding to an individual GPIO port (Port A, Port B, Port C, Port D, and Port E). The GPIO module is FiRM-compliant and supports 3 to 30 programmable input/output pins, depending on the peripherals being used. The GPIO module has the following features: Programmable control for GPIO interrupts: - Interrupt generation masking - Edge-triggered on rising, falling, or both - Level-sensitive on High or Low values 5-V-tolerant input/outputs Bit masking in both read and write operations through address lines Programmable control for GPIO pad configuration: - Weak pull-up or pull-down resistors - 2-mA, 4-mA, and 8-mA pad drive - Slew rate control for the 8-mA drive - Open drain enables - Digital input enables
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LM3S317 Data Sheet
8.1
Figure 8-1.
PA0 GPIO Port A PA1 PA2 PA3 PA4 PA5
Block Diagram
GPIO Module Block Diagram
U0Rx U0Tx SSICLK SSIFss SSIRx SSITx UART0 JTAG SWD/SWO TCK/SWCLK TMS/SWDIO TDO/SWO GPIO Port C TDI TRST SSI PC0 PC1 PC2 PC3 PC4 PC5 PC6
PB0 PB1 GPIO Port B PB2 PB3 PB4 PB5 PB6 PB7
PWM2 PWM3
PWM1 Fault
CCP5 Fault
GP Timer 2
CCP4 PWM0 GPIO Port D PWM1
PC7 PD0 PD1 PD2 PD3 PD4 PD5
PWM0
C0C0o C0+
Analog Comparators
CCP1 CCP3
GP Timer 0 GP Timer 1
CCP0 CCP2
GPIO Block E
Fault
PWM2
PWM4 PWM5
PE0 PE1
LM3S317
8.2
Functional Description
Important: All GPIO pins are inputs by default (GPIODIR=0 and GPIOAFSEL=0), with the exception of the five JTAG pins (PB7 and PC[3:0]. The JTAG pins default to their JTAG functionality (GPIOAFSEL=1). Asserting a Power-On-Reset (POR) or an external reset (RST) puts both groups of pins back to their default state. Each GPIO port is a separate hardware instantiation of the same physical block (see Figure 8-2). The LM3S317 microcontroller contains five ports and thus five of these physical GPIO blocks.
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General-Purpose Input/Outputs (GPIOs)
Figure 8-2.
GPIO Port Block Diagram
Function Selection GPIOAFSEL
Alternate Input Alternate Output Alternate Output Enable GPIO Input GPIO Output GPIO Output Enable
D E M U X M U X
Pad Input
Pad Output
I/O Data GPIODATA GPIODIR
I/O Pad
Package I/O Pin
M U X
Pad Output Enable
Interrupt Control GPIOIS GPIOIBE GPIOIEV GPIOIM GPIORIS GPIOMIS GPIOICR
I/O Pad Control GPIODR2R GPIODR4R GPIODR8R GPIOSLR GPIOPUR GPIOPDR GPIOODR GPIODEN
Interrupt
Identification Registers GPIOPeriphID0 GPIOPeriphID1 GPIOPeriphID2 GPIOPeriphID3 GPIOPeriphID4 GPIOPeriphID5 GPIOPeriphID6 GPIOPeriphID7 GPIOPCellID0 GPIOPCellID1 GPIOPCellID2 GPIOPCellID3
8.2.1
Data Register Operation
To aid in the efficiency of software, the GPIO ports allow for the modification of individual bits in the GPIO Data (GPIODATA) register (see page 122) by using bits [9:2] of the address bus as a mask. This allows software drivers to modify individual GPIO pins in a single instruction, without affecting the state of the other pins. This is in contrast to the "typical" method of doing a read-modify-write operation to set or clear an individual GPIO pin. To accommodate this feature, the GPIODATA register covers 256 locations in the memory map. During a write, if the address bit associated with that data bit is set to 1, the value of the GPIODATA register is altered. If it is cleared to 0, it is left unchanged. For example, writing a value of 0xEB to the address GPIODATA + 0x098 would yield as shown in Figure 8-3, where u is data unchanged by the write.
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Figure 8-3.
GPIODATA Write Example
ADDR[9:2] 0x098 0xEB GPIODATA 9 0 1 u 7 8 0 1 u 6 7 1 1 1 5 6 0 0 u 4 5 0 1 u 3 4 1 0 0 2 3 1 1 1 1 2 0 1 u 0 1 0 0 0
During a read, if the address bit associated with the data bit is set to 1, the value is read. If the address bit associated with the data bit is set to 0, it is read as a zero, regardless of its actual value. For example, reading address GPIODATA + 0x0C4 yields as shown in Figure 8-4. Figure 8-4. GPIODATA Read Example
ADDR[9:2] 0x0C4 GPIODATA Returned Value 9 0 1 0 7 8 0 0 0 6 7 1 1 1 5 6 1 1 1 4 5 0 1 0 3 4 0 1 0 2 3 0 1 0 1 2 1 0 0 0 1 0 0 0
8.2.2
Data Direction
The GPIO Direction (GPIODIR) register (see page 123) is used to configure each individual pin as an input or output.
8.2.3
Interrupt Operation
The interrupt capabilities of each GPIO port are controlled by a set of seven registers. With these registers, it is possible to select the source of the interrupt, its polarity, and the edge properties. When one or more GPIO inputs cause an interrupt, a single interrupt output is sent to the interrupt controller for the entire GPIO port. For edge-triggered interrupts, software must clear the interrupt to enable any further interrupts. For a level-sensitive interrupt, it is assumed that the external source holds the level constant for the interrupt to be recognized by the controller. Three registers are required to define the edge or sense that causes interrupts: GPIO Interrupt Sense (GPIOIS) register (see page 124) GPIO Interrupt Both Edges (GPIOIBE) register (see page 125) GPIO Interrupt Event (GPIOIEV) register (see page 126) Interrupts are enabled/disabled via the GPIO Interrupt Mask (GPIOIM) register (see page 127). When an interrupt condition occurs, the state of the interrupt signal can be viewed in two locations: the GPIO Raw Interrupt Status (GPIORIS) and GPIO Masked Interrupt Status (GPIOMIS) registers (see pages 128 and 129). As the name implies, the GPIOMIS register only shows interrupt conditions that are allowed to be passed to the controller. The GPIORIS register indicates that a GPIO pin meets the conditions for an interrupt, but has not necessarily been sent to the controller.
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General-Purpose Input/Outputs (GPIOs)
In addition to providing GPIO functionality, PB4 can also be used as an external trigger for the ADC. If PB4 is configured as a non-masked interrupt pin (GPIOIM is set to 1), not only is an interrupt for PortB generated, but an external trigger signal is sent to the ADC. If the ADC Event Multiplexer Select (ADCEMUX) register is configured to use the external trigger, an ADC conversion is initiated. If no other PortB pins are being used to generate interrupts, the ARM Integrated Nested Vectored Interrupt Controller (NVIC) Interrupt Set Enable (SETNA) register can disable the PortB interrupts and the ADC interrupt can be used to read back the converted data. Otherwise, the PortB interrupt handler needs to ignore and clear interrupts on B4, and wait for the ADC interrupt or the ADC interrupt needs to be disabled in the SETNA register and the PortB interrupt handler polls the ADC registers until the conversion is completed. Interrupts are cleared by writing a 1 to the GPIO Interrupt Clear (GPIOICR) register (see page 130). When programming interrupts, the interrupts should be masked (GPIOIM set to 0). Writing any value to an interrupt control register (GPIOIS, GPIOIBE, or GPIOIEV) can generate a spurious interrupt if the corresponding bits are enabled.
8.2.4
Mode Control
The GPIO pins can be controlled by either hardware or software. When hardware control is enabled via the GPIO Alternate Function Select (GPIOAFSEL) register (see page 131), the pin state is controlled by its alternate function (that is, the peripheral). Software control corresponds to GPIO mode, where the GPIODATA register is used to read/write the corresponding pins.
8.2.5
Pad Configuration
The pad configuration registers allow for GPIO pad configuration by software based on the application requirements. The pad configuration registers include the GPIODR2R, GPIODR4R, GPIODR8R, GPIOODR, GPIOPUR, GPIOPDR, GPIOSLR, and GPIODEN registers.
8.2.6
Identification
The identification registers configured at reset allow software to detect and identify the module as a GPIO block. The identification registers include the GPIOPeriphID0-GPIOPeriphID7 registers as well as the GPIOPCellID0-GPIOPCellID3 registers.
8.3
Initialization and Configuration
To use the GPIO, the peripheral clock must be enabled by setting PORTA, PORTB, PORTC, PORTD, and PORTE in the RCGC2 register. On reset, all GPIO pins (except for the five JTAG pins) default to general-purpose input mode (GPIODIR and GPIOAFSEL both set to 0). Table 8-1 shows all possible configurations of the
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GPIO pads and the control register settings required to achieve them. Table 8-2 shows how a rising edge interrupt would be configured for pin 2 of a GPIO port. Table 8-1. GPIO Pad Configuration Examples
Register Bit Valuea GPIOAFSEL GPIODR2R GPIODR4R GPIODR8R X ? X ? X ? ? ? ? X ? GPIOODR GPIODEN GPIOPUR GPIOPDR Configuration GPIOSLR X ? X ? X ? ? ? ? X ? 0 X X X 0 119 Preliminary GPIODIR 0 1 0 1 X X X X X 0 X
Digital Input (GPIO) Digital Output (GPIO) Open Drain Input (GPIO) Open Drain Output (GPIO) Digital Input (Timer CCP) Digital Output (PWM) Digital Output (Timer PWM) Digital Input/Output (SSI) Digital Input/Output (UART) Analog Input (Comparator) Digital Output (Comparator)
0 0 0 0 1 1 1 1 1 0 1
0 0 1 1 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 0 1
? ? X X ? ? ? ? ? 0 ?
? ? X X ? ? ? ? ? 0 ?
X ? X ? X ? ? ? ? X ?
X ? X ? X ? ? ? ? X ?
a. X=Ignored (don't care bit) ?=Can be either 0 or 1, depending on the configuration
Table 8-2.
Register GPIOIS GPIOIBE GPIOIEV
GPIO Interrupt Configuration Example
Desired Interrupt Event Trigger 0=edge 1=level 0=single edge 1=both edges 0=Low level, or negative edge 1=High level, or positive edge 0=masked 1=not masked Pin 2 Bit Valuea 7 X X 6 X X 5 X X 4 X X 3 X X 2 0 0 1 X X
X
X
X
X
X
1
X
GPIOIM
0
0
0
0
0
1
0
a. X=Ignored (don't care bit)
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General-Purpose Input/Outputs (GPIOs)
8.4
Register Map
Table 8-2 lists the GPIO registers. The offset listed is a hexadecimal increment to the register's address, relative to that GPIO port's base address: GPIO Port A: 0x40004000 GPIO Port B: 0x40005000 GPIO Port C: 0x40006000 GPIO Port D: 0x40007000 GPIO Port E: 0x40024000 Important: The GPIO registers in this chapter are duplicated in each GPIO block, however, depending on the block, all eight bits may not be connected to a GPIO pad (see Figure 8-1 on page 115). In those cases, writing to those unconnected bits has no effect and reading those unconnected bits returns no meaningful data.
Table 8-3. GPIO Register Map
Offset 0x000 0x400 0x404 0x408 0x40C 0x410 0x414 0x418 0x41C 0x420 0x500 0x504 0x508 0x50C 0x510 0x514 0x518 0x51C 0xFD0 Name GPIODATA GPIODIR GPIOIS GPIOIBE GPIOIEV GPIOIM GPIORIS GPIOMIS GPIOICR GPIOAFSEL GPIODR2R GPIODR4R GPIODR8R GPIOODR GPIOPUR GPIOPDR GPIOSLR GPIODEN GPIOPeriphID4 Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 see notea 0x000000FF 0x00000000 0x00000000 0x00000000 0x000000FF 0x00000000 0x00000000 0x000000FF 0x00000000 Type R/W R/W R/W R/W R/W R/W RO RO W1C R/W R/W R/W R/W R/W R/W R/W R/W R/W RO Description Data Data direction Interrupt sense Interrupt both edges Interrupt event Interrupt mask enable Raw interrupt status Masked interrupt status Interrupt clear Alternate function select 2-mA drive select 4-mA drive select 8-mA drive select Open drain select Pull-up select Pull-down select Slew rate control select Digital input enable Peripheral identification 4 See page 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
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Table 8-3. GPIO Register Map (Continued)
Offset 0xFD4 0xFD8 0xFDC 0xFE0 0xFE4 0xFE8 0xFEC 0xFF0 0xFF4 0xFF8 0xFFC Name GPIOPeriphID5 GPIOPeriphID6 GPIOPeriphID7 GPIOPeriphID0 GPIOPeriphID1 GPIOPeriphID2 GPIOPeriphID3 GPIOPCellID0 GPIOPCellID1 GPIOPCellID2 GPIOPCellID3 Reset 0x00000000 0x00000000 0x00000000 0x00000061 0x00000000 0x00000018 0x00000001 0x0000000D 0x000000F0 0x00000005 0x000000B1 Type RO RO RO RO RO RO RO RO RO RO RO Description Peripheral identification 5 Peripheral identification 6 Peripheral identification 7 Peripheral identification 0 Peripheral identification 1 Peripheral identification 2 Peripheral identification 3 GPIO PrimeCell identification 0 GPIO PrimeCell identification 1 GPIO PrimeCell identification 2 GPIO PrimeCell identification 3 See page 141 142 143 144 145 146 147 148 149 150 151
a. The default reset value for the GPIOAFSEL register is 0x00000000 for all GPIO pins, with the exception of the five JTAG pins (PB7 and PC[3:0]. These five pins default to JTAG functionality. Because of this, the default reset value of GPIOAFSEL for GPIO Port B is 0x00000080 while the default reset value of GPIOAFSEL for Port C is 0x0000000F.
8.5
Register Descriptions
The remainder of this section lists and describes the GPIO registers, in numerical order by address offset.
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General-Purpose Input/Outputs (GPIOs)
Register 1: GPIO Data (GPIODATA), offset 0x000 The GPIODATA register is the data register. In software control mode, values written in the GPIODATA register are transferred onto the GPIO port pins if the respective pins have been configured as outputs through the GPIO Direction (GPIODIR) register (see page 123). In order to write to GPIODATA, the corresponding bits in the mask, resulting from the address bus bits [9:2], must be High. Otherwise, the bit values remain unchanged by the write. Similarly, the values read from this register are determined for each bit by the mask bit derived from the address used to access the data register, bits [9:2]. Bits that are 1 in the address mask cause the corresponding bits in GPIODATA to be read, and bits that are 0 in the address mask cause the corresponding bits in GPIODATA to be read as 0, regardless of their value. A read from GPIODATA returns the last bit value written if the respective pins are configured as outputs, or it returns the value on the corresponding input pin when these are configured as inputs. All bits are cleared by a reset.
GPIO Data (GPIODATA)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0
DATA
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved DATA
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Data This register is virtually mapped to 256 locations in the address space. To facilitate the reading and writing of data to these registers by independent drivers, the data read from and the data written to the registers are masked by the eight address lines ipaddr[9:2]. Reads from this register return its current state. Writes to this register only affect bits that are not masked by ipaddr[9:2] and are configured as outputs. See "Data Register Operation" on page 116 for examples of reads and writes.
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Register 2: GPIO Direction (GPIODIR), offset 0x400 The GPIODIR register is the data direction register. Bits set to 1 in the GPIODIR register configure the corresponding pin to be an output, while bits set to 0 configure the pins to be inputs. All bits are cleared by a reset, meaning all GPIO pins are inputs by default.
GPIO Direction (GPIODIR)
Offset 0x400
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
DIR
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved DIR
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Data Direction 0: Pins are inputs. 1: Pins are outputs.
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General-Purpose Input/Outputs (GPIOs)
Register 3: GPIO Interrupt Sense (GPIOIS), offset 0x404 The GPIOIS register is the interrupt sense register. Bits set to 1 in GPIOIS configure the corresponding pins to detect levels, while bits set to 0 configure the pins to detect edges. All bits are cleared by a reset.
GPIO Interrupt Sense (GPIOIS)
Offset 0x404
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
IS
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved IS
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Interrupt Sense 0: Edge on corresponding pin is detected (edge-sensitive). 1: Level on corresponding pin is detected (level-sensitive).
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Register 4: GPIO Interrupt Both Edges (GPIOIBE), offset 0x408 The GPIOIBE register is the interrupt both-edges register. When the corresponding bit in the GPIO Interrupt Sense (GPIOIS) register (see page 124) is set to detect edges, bits set to High in GPIOIBE configure the corresponding pin to detect both rising and falling edges, regardless of the corresponding bit in the GPIO Interrupt Event (GPIOIEV) register (see page 126). Clearing a bit configures the pin to be controlled by GPIOIEV. All bits are cleared by a reset.
GPIO Interrupt Both Edges (GPIOIBE)
Offset 0x408
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
IBE
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved IBE
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Interrupt Both Edges 0: Interrupt generation is controlled by the GPIO Interrupt Event (GPIOIEV) register (see page 142). 1: Both edges on the corresponding pin trigger an interrupt. Note: Single edge is determined by the corresponding bit in GPIOIEV.
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General-Purpose Input/Outputs (GPIOs)
Register 5: GPIO Interrupt Event (GPIOIEV), offset 0x40C The GPIOIEV register is the interrupt event register. Bits set to High in GPIOIEV configure the corresponding pin to detect rising edges or high levels, depending on the corresponding bit value in the GPIO Interrupt Sense (GPIOIS) register (see page 124). Clearing a bit configures the pin to detect falling edges or low levels, depending on the corresponding bit value in GPIOIS. All bits are cleared by a reset.
GPIO Interrupt Event (GPIOIEV)
Offset 0x40C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
IEV
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved IEV
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Interrupt Event 0: Falling edge or Low levels on corresponding pins trigger interrupts. 1: Rising edge or High levels on corresponding pins trigger interrupts.
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Register 6: GPIO Interrupt Mask (GPIOIM), offset 0x410 The GPIOIM register is the interrupt mask register. Bits set to High in GPIOIM allow the corresponding pins to trigger their individual interrupts and the combined GPIOINTR line. Clearing a bit disables interrupt triggering on that pin. All bits are cleared by a reset.
GPIO Interrupt Mask (GPIOIM)
Offset 0x410
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
IME
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved IME
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Interrupt Mask Enable 0: Corresponding pin interrupt is masked. 1: Corresponding pin interrupt is not masked.
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General-Purpose Input/Outputs (GPIOs)
Register 7: GPIO Raw Interrupt Status (GPIORIS), offset 0x414 The GPIORIS register is the raw interrupt status register. Bits read High in GPIORIS reflect the status of interrupt trigger conditions detected (raw, prior to masking), indicating that all the requirements have been met, before they are finally allowed to trigger by the GPIO Interrupt Mask (GPIOIM) register (see page 127). Bits read as zero indicate that corresponding input pins have not initiated an interrupt. All bits are cleared by a reset.
GPIO Raw Interrupt Status (GPIORIS)
Offset 0x414
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
RIS
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved RIS
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Interrupt Raw Status Reflect the status of interrupt trigger condition detection on pins (raw, prior to masking). 0: Corresponding pin interrupt requirements not met. 1: Corresponding pin interrupt has met requirements.
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Register 8: GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 The GPIOMIS register is the masked interrupt status register. Bits read High in GPIOMIS reflect the status of input lines triggering an interrupt. Bits read as Low indicate that either no interrupt has been generated, or the interrupt is masked. In addition to providing GPIO functionality, PB4 can also be used as an external trigger for the ADC. If PB4 is configured as a non-masked interrupt pin (GPIOIM is set to 1), not only is an interrupt for PortB generated, but an external trigger signal is sent to the ADC. If the ADC Event Multiplexer Select (ADCEMUX) register (see page 218) is configured to use the external trigger, an ADC conversion is initiated. If no other PortB pins are being used to generate interrupts, the ARM Integrated Nested Vectored Interrupt Controller (NVIC) Interrupt Set Enable (SETNA) register can disable the PortB interrupts and the ADC interrupt can be used to read back the converted data. Otherwise, the PortB interrupt handler needs to ignore and clear interrupts on B4, and wait for the ADC interrupt or the ADC interrupt needs to be disabled in the SETNA register and the PortB interrupt handler polls the ADC registers until the conversion is completed. GPIOMIS is the state of the interrupt after masking.
GPIO Masked Interrupt Status (GPIOMIS)
Offset 0x418
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
MIS
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved MIS
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Masked Interrupt Status Masked value of interrupt due to corresponding pin. 0: Corresponding GPIO line interrupt not active. 1: Corresponding GPIO line asserting interrupt.
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General-Purpose Input/Outputs (GPIOs)
Register 9: GPIO Interrupt Clear (GPIOICR), offset 0x41C The GPIOICR register is the interrupt clear register. Writing a 1 to a bit in this register clears the corresponding interrupt edge detection logic register. Writing a 0 has no effect.
GPIO Interrupt Clear (GPIOICR)
Offset 0x41C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 W1C 0 W1C 0 W1C 0 W1C 0
IC
W1C 0 W1C 0 W1C 0 W1C 0
Bit/Field 31:8 7:0
Name reserved IC
Type RO W1C
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Interrupt Clear 0: Corresponding interrupt is unaffected. 1: Corresponding interrupt is cleared.
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Register 10: GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 The GPIOAFSEL register is the mode control select register. Writing a 1 to any bit in this register selects the hardware control for the corresponding GPIO line. All bits are cleared by a reset, therefore no GPIO line is set to hardware control by default. Caution - All GPIO pins are inputs by default (GPIODIR=0 and GPIOAFSEL=0), with the exception of the five JTAG pins (PB7 and PC[3:0]). The JTAG pins default to their JTAG functionality (GPIOAFSEL=1). Asserting a Power-On-Reset (POR) or an external reset (RST) puts both groups of pins back to their default state. If the JTAG pins are used as GPIOs in a design, PB7 and PC2 cannot have external pull-down resistors connected to both of them at the same time. If both pins are pulled Low during reset, the controller has unpredictable behavior. If this happens, remove one or both of the pull-down resistors, and apply RST or power-cycle the part. In addition, it is possible to create a software sequence that prevents the debugger from connecting to the Stellaris microcontroller. If the program code loaded into flash immediately changes the JTAG pins to their GPIO functionality, the debugger may not have enough time to connect and halt the controller before the JTAG pin functionality switches. This may lock the debugger out of the part. This can be avoided with a software routine that restores JTAG functionality based on an external or software trigger.
GPIO Alternate Function Select (GPIOAFSEL)
Offset 0x420
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W R/W R/W -
AFSEL
R/W R/W R/W R/W R/W -
Bit/Field 31:8 7:0
Name reserved AFSEL
Type RO R/W
Reset 0 see note
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Alternate Function Select 0: Software control of corresponding GPIO line (GPIO mode). 1: Hardware control of corresponding GPIO line (alternate hardware function). Note: The default reset value for the GPIOAFSEL register is 0x00 for all GPIO pins, with the exception of the five JTAG pins (PB7 and PC[3:0]). These five pins default to JTAG functionality. Because of this, the default reset value of GPIOAFSEL for GPIO Port B is 0x80 while the default reset value of GPIOAFSEL for Port C is 0x0F.
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General-Purpose Input/Outputs (GPIOs)
Register 11: GPIO 2-mA Drive Select (GPIODR2R), offset 0x500 The GPIODR2R register is the 2-mA drive control register. It allows for each GPIO signal in the port to be individually configured without affecting the other pads. When writing a DRV2 bit for a GPIO signal, the corresponding DRV4 bit in the GPIODR4R register and the DRV8 bit in the GPIODR8R register are automatically cleared by hardware.
GPIO 2-mA Drive Select (GPIODR2R)
Offset 0x500
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 1 R/W 1 R/W 1 R/W 1
DRV2
R/W 1 R/W 1 R/W 1 R/W 1
Bit/Field 31:8 7:0
Name reserved DRV2
Type RO R/W
Reset 0 0xFF
Description Reserved bits return an indeterminate value, and should never be changed. Output Pad 2-mA Drive Enable A write of 1 to either GPIODR4[n] or GPIODR8[n] clears the corresponding 2-mA enable bit. The change is effective on the second clock cycle after the write.
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LM3S317 Data Sheet
Register 12: GPIO 4-mA Drive Select (GPIODR4R), offset 0x504 The GPIODR4R register is the 4-mA drive control register. It allows for each GPIO signal in the port to be individually configured without affecting the other pads. When writing the DRV4 bit for a GPIO signal, the corresponding DRV2 bit in the GPIODR2R register and the DRV8 bit in the GPIODR8R register are automatically cleared by hardware.
GPIO 4-mA Drive Select (GPIODR4R)
Offset 0x504
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
DRV4
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved DRV4
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. Output Pad 4-mA Drive Enable A write of 1 to either GPIODR2[n] or GPIODR8[n] clears the corresponding 4-mA enable bit. The change is effective on the second clock cycle after the write.
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133
General-Purpose Input/Outputs (GPIOs)
Register 13: GPIO 8-mA Drive Select (GPIODR8R), offset 0x508 The GPIODR8R register is the 8-mA drive control register. It allows for each GPIO signal in the port to be individually configured without affecting the other pads. When writing the DRV8 bit for a GPIO signal, the corresponding DRV2 bit in the GPIODR2R register and the DRV4 bit in the GPIODR4R register are automatically cleared by hardware.
GPIO 8-mA Drive Select (GPIODR8R)
Offset 0x508
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
DRV8
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved DRV8
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. Output Pad 8-mA Drive Enable A write of 1 to either GPIODR2[n] or GPIODR4[n] clears the corresponding 8-mA enable bit. The change is effective on the second clock cycle after the write.
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LM3S317 Data Sheet
Register 14: GPIO Open Drain Select (GPIOODR), offset 0x50C The GPIOODR register is the open drain control register. Setting a bit in this register enables the open drain configuration of the corresponding GPIO pad. When open drain mode is enabled, the corresponding bit should also be set in the GPIO Digital Input Enable (GPIODEN) register (see page 139). Corresponding bits in the drive strength registers (GPIODR2R, GPIODR4R, GPIODR8R, and GPIOSLR) can be set to achieve the desired rise and fall times. The GPIO acts as an open drain input if the corresponding bit in the GPIODIR register is set to 0; and as an open drain output when set to 1.
GPIO Open Drain Select (GPIOODR)
Offset 0x50C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
ODE
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved ODE
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. Output Pad Open Drain Enable 0: Open drain configuration is disabled. 1: Open drain configuration is enabled.
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135
General-Purpose Input/Outputs (GPIOs)
Register 15: GPIO Pull-Up Select (GPIOPUR), offset 0x510 The GPIOPUR register is the pull-up control register. When a bit is set to 1, it enables a weak pull-up resistor on the corresponding GPIO signal. Setting a bit in GPIOPUR automatically clears the corresponding bit in the GPIO Pull-Down Select (GPIOPDR) register (see page 137).
GPIO Pull-Up Select (GPIOPUR)
Offset 0x510
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 1 R/W 1 R/W 1 R/W 1
PUE
R/W 1 R/W 1 R/W 1 R/W 1
Bit/Field 31:8 7:0
Name reserved PUE
Type RO R/W
Reset 0 0xFF
Description Reserved bits return an indeterminate value, and should never be changed. Pad Weak Pull-Up Enable A write of 1 to GPIOPDR[n] clears the corresponding GPIOPUR[n] enables. The change is effective on the second clock cycle after the write.
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LM3S317 Data Sheet
Register 16: GPIO Pull-Down Select (GPIOPDR), offset 0x514 The GPIOPDR register is the pull-down control register. When a bit is set to 1, it enables a weak pull-down resistor on the corresponding GPIO signal. Setting a bit in GPIOPDR automatically clears the corresponding bit in the GPIO Pull-Up Select (GPIOPUR) register (see page 136).
GPIO Pull-Down Select (GPIOPDR)
Offset 0x514
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
PDE
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved PDE
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. Pad Weak Pull-Down Enable A write of 1 to GPIOPUR[n] clears the corresponding GPIOPDR[n] enables. The change is effective on the second clock cycle after the write.
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137
General-Purpose Input/Outputs (GPIOs)
Register 17: GPIO Slew Rate Control Select (GPIOSLR), offset 0x518 The GPIOSLR register is the slew rate control register. Slew rate control is only available when using the 8-mA drive strength option via the GPIO 8-mA Drive Select (GPIODR8R) register (see page 134).
GPIO Slew Rate Control Select (GPIOSLR)
Offset 0x518
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
SRL
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved SRL
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Slew Rate Limit Enable (8-mA drive only) 0: Slew rate control disabled. 1: Slew rate control enabled.
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LM3S317 Data Sheet
Register 18: GPIO Digital Input Enable (GPIODEN), offset 0x51C The GPIODEN register is the digital input enable register. By default, all GPIO signals are configured as digital inputs at reset. The only time that a pin should not be configured as a digital input is when the GPIO pin is configured to be one of the analog input signals for the analog comparator.
GPIO Digital Input Enable (GPIODEN)
Offset 0x51C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 1 R/W 1 R/W 1 R/W 1
DEN
R/W 1 R/W 1 R/W 1 R/W 1
Bit/Field 31:8 7:0
Name reserved DEN
Type RO R/W
Reset 0 0xFF
Description Reserved bits return an indeterminate value, and should never be changed. Digital-Input Enable 0: Digital input disabled 1: Digital input enabled
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139
General-Purpose Input/Outputs (GPIOs)
Register 19: GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 4 (GPIOPeriphID4)
Offset 0xFD0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID4
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID4
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[7:0]
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LM3S317 Data Sheet
Register 20: GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 5 (GPIOPeriphID5)
Offset 0xFD4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID5
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID5
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[15:8]
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141
General-Purpose Input/Outputs (GPIOs)
Register 21: GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 6 (GPIOPeriphID6)
Offset 0xFD8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID6
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID6
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[23:16]
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LM3S317 Data Sheet
Register 22: GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 7 (GPIOPeriphID7)
Offset 0xFDC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID7
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID7
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[31:24]
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143
General-Purpose Input/Outputs (GPIOs)
Register 23: GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 0 (GPIOPeriphID0)
Offset 0xFE0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 0
PID0
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID0
Type RO RO
Reset 0 0x61
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral.
144 Preliminary
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LM3S317 Data Sheet
Register 24: GPIO Peripheral Identification 1(GPIOPeriphID1), offset 0xFE4 The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 1 (GPIOPeriphID1)
Offset 0xFE4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID1
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[15:8] Can be used by software to identify the presence of this peripheral.
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145
General-Purpose Input/Outputs (GPIOs)
Register 25: GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 2 (GPIOPeriphID2)
Offset 0xFE8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1
PID2
RO 1 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID2
Type RO RO
Reset 0 0x18
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[23:16] Can be used by software to identify the presence of this peripheral.
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LM3S317 Data Sheet
Register 26: GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral.
GPIO Peripheral Identification 3 (GPIOPeriphID3)
Offset 0xFEC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID3
Type RO RO
Reset 0 0x01
Description Reserved bits return an indeterminate value, and should never be changed. GPIO Peripheral ID Register[31:24] Can be used by software to identify the presence of this peripheral.
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147
General-Purpose Input/Outputs (GPIOs)
Register 27: GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system.
GPIO Primecell Identification 0 (GPIOPCellID0)
Offset 0xFF0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID0
RO 1 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID0
Type RO RO
Reset 0 0x0D
Description Reserved bits return an indeterminate value, and should never be changed. GPIO PrimeCell ID Register[7:0] Provides software a standard cross-peripheral identification system.
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LM3S317 Data Sheet
Register 28: GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system.
GPIO Primecell Identification 1 (GPIOPCellID1)
Offset 0xFF4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 1
CID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved CID1
Type RO RO
Reset 0 0xF0
Description Reserved bits return an indeterminate value, and should never be changed. GPIO PrimeCell ID Register[15:8] Provides software a standard cross-peripheral identification system.
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General-Purpose Input/Outputs (GPIOs)
Register 29: GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system.
GPIO Primecell Identification 2 (GPIOPCellID2)
Offset 0xFF8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID2
RO 0 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID2
Type RO RO
Reset 0 0x05
Description Reserved bits return an indeterminate value, and should never be changed. GPIO PrimeCell ID Register[23:16] Provides software a standard cross-peripheral identification system.
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LM3S317 Data Sheet
Register 30: GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system.
GPIO Primecell Identification 3 (GPIOPCellID3)
Offset 0xFFC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 RO 1
CID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID3
Type RO RO
Reset 0 0xB1
Description Reserved bits return an indeterminate value, and should never be changed. GPIO PrimeCell ID Register[31:24] Provides software a standard cross-peripheral identification system.
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General-Purpose Timers
9
General-Purpose Timers
Programmable timers can be used to count or time external events that drive the Timer input pins. The LM3S317 controller General-Purpose Timer Module (GPTM) contains three GPTM blocks (Timer0, Timer1, and Timer 2). Each GPTM block provides two 16-bit timer/counters (referred to as TimerA and TimerB) that can be configured to operate independently as timers or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC). Timers can also be used to trigger analog-to-digital (ADC) conversions. The trigger signals from all of the general-purpose timers are ORed together before reaching the ADC module, so only one timer should be used to trigger ADC events. The General-Purpose Timer Module is one timing resource available on the Stellaris microcontrollers. Other timer resources include the System Timer (SysTick) (see "System Timer (SysTick)" on page 35) and the PWM timer in the PWM module (see "PWM Timer" on page 319). The following modes are supported: 32-bit Timer modes: - Programmable one-shot timer - Programmable periodic timer - Real-Time Clock using 32.768-KHz input clock - Software-controlled event stalling (excluding RTC mode) 16-bit Timer modes: - General-purpose timer function with an 8-bit prescaler - Programmable one-shot timer - Programmable periodic timer - Software-controlled event stalling 16-bit Input Capture modes: - Input edge count capture - Input edge time capture 16-bit PWM mode: - Simple PWM mode with software-programmable output inversion of the PWM signal
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LM3S317 Data Sheet
9.1
Block Diagram
Figure 9-1. GPTM Module Block Diagram
0x0000 (Down Counter Modes )
TimerA Control GPTMTAPMR GPTMTAPR GPTMTAMATCHR Interrupt / Config TimerA Interrupt GPTMCFG GPTMCTL GPTMIMR TimerB Interrupt GPTMRIS GPTMMIS GPTMICR TimerB Control GPTMTBPMR GPTMTBPR GPTMTBMATCHR GPTMTBILR GPTMTBMR TB Comparator GPTMTBR En Clock / Edge Detect CCP (odd) RTC Divider GPTMTAILR GPTMTAMR GPTMAR En Clock / Edge Detect TA Comparator
CCP (even)
0x0000 (Down Counter Modes ) System Clock
9.2
Functional Description
The main components of each GPTM block are two free-running 16-bit up/down counters (referred to as TimerA and TimerB), two 16-bit match registers, two prescaler match registers, and two 16-bit load/initialization registers and their associated control functions. The exact functionality of each GPTM is controlled by software and configured through the register interface. Software configures the GPTM using the GPTM Configuration (GPTMCFG) register (see page 164), the GPTM TimerA Mode (GPTMTAMR) register (see page 165), and the GPTM TimerB Mode (GPTMTBMR) register (see page 166). When in one of the 32-bit modes, the timer can only act as a 32-bit timer. However, when configured in 16-bit mode, the GPTM can have its two 16-bit timers configured in any combination of the 16-bit modes.
9.2.1
GPTM Reset Conditions
After reset has been applied to the GPTM module, the module is in an inactive state, and all control registers are cleared and in their default states. Counters TimerA and TimerB are initialized to 0xFFFF, along with their corresponding load registers: the GPTM TimerA Interval Load (GPTMTAILR) register (see page 174) and the GPTM TimerB Interval Load (GPTMTBILR) register (see page 175). The prescale counters are initialized to 0x00: the GPTM TimerA Prescale (GPTMTAPR) register (see page 178) and the GPTM TimerB Prescale (GPTMTBPR) register (see page 179).
9.2.2
32-Bit Timer Operating Modes
Note: Both the odd- and even-numbered CCP pins are used for 16-bit mode. Only the even-numbered CCP pins are used for 32-bit mode.
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General-Purpose Timers
This section describes the three GPTM 32-bit timer modes (One-Shot, Periodic, and RTC) and their configuration. The GPTM is placed into 32-bit mode by writing a 0 (One-Shot/Periodic 32-bit timer mode) or a 1 (RTC mode) to the GPTM Configuration (GPTMCFG) register. In both configurations, certain GPTM registers are concatenated to form pseudo 32-bit registers. These registers include: GPTM TimerA Interval Load (GPTMTAILR) register [15:0], see page 174 GPTM TimerB Interval Load (GPTMTBILR) register [15:0], see page 175 GPTM TimerA (GPTMTAR) register [15:0], see page 182 GPTM TimerB (GPTMTBR) register [15:0], see page 183 In the 32-bit modes, the GPTM translates a 32-bit write access to GPTMTAILR into a write access to both GPTMTAILR and GPTMTBILR. The resulting word ordering for such a write operation is: GPTMTBILR[15:0]:GPTMTAILR[15:0]. Likewise, a read access to GPTMTAR returns the value: GPTMTBR[15:0]:GPTMTAR[15:0]. 9.2.2.1 32-Bit One-Shot/Periodic Timer Mode In 32-bit one-shot and periodic timer modes, the concatenated versions of the TimerA and TimerB registers are configured as a 32-bit down-counter. The selection of one-shot or periodic mode is determined by the value written to the TAMR field of the GPTM TimerA Mode (GPTMTAMR) register (see page 165), and there is no need to write to the GPTM TimerB Mode (GPTMTBMR) register. When software writes the TAEN bit in the GPTM Control (GPTMCTL) register (see page 167), the timer begins counting down from its preloaded value. Once the 0x00000000 state is reached, the timer reloads its start value from the concatenated GPTMTAILR on the next cycle. If configured to be a one-shot timer, the timer stops counting and clears the TAEN bit in the GPTMCTL register. If configured as a periodic timer, it continues counting. In addition to reloading the count value, the GPTM generates interrupts and output triggers when it reaches the 0x0000000 state. The GPTM sets the TATORIS bit in the GPTM Raw Interrupt Status (GPTMRIS) register (see page 171), and holds it until it is cleared by writing the GPTM Interrupt Clear (GPTMICR) register (see page 173). If the time-out interrupt is enabled in the GPTM Interrupt Mask (GPTIMR) register (see page 169), the GPTM also sets the TATOMIS bit in the GPTM Masked Interrupt Status (GPTMISR) register (see page 172). The output trigger is a one-clock-cycle pulse that is asserted when the counter hits the 0x00000000 state, and deasserted on the following clock cycle. It is enabled by setting the TAOTE bit in GPTMCTL, and can trigger SoC-level events such as ADC conversions. If software reloads the GPTMTAILR register while the counter is running, the counter loads the new value on the next clock cycle and continues counting from the new value. If the TASTALL bit in the GPTMCTL register is asserted, the timer freezes counting until the signal is deasserted. 9.2.2.2 32-Bit Real-Time Clock Timer Mode In Real-Time Clock (RTC) mode, the concatenated versions of the TimerA and TimerB registers are configured as a 32-bit up-counter. When RTC mode is selected for the first time, the counter is loaded with a value of 0x00000001. All subsequent load values must be written to the GPTM TimerA Match (GPTMTAMATCHR) register (see page 176) by the controller. The input clock on the CCP0, CCP2 or CCP4 pins is required to be 32.768 KHz in RTC mode. The clock signal is then divided down to a 1 Hz rate and is passed along to the input of the 32-bit counter.
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When software writes the TAEN bit in GPTMCTL, the counter starts counting up from its preloaded value of 0x00000001. When the current count value matches the preloaded value in GPTMTAMATCHR, it rolls over to a value of 0x00000000 and continues counting until either a hardware reset, or it is disabled by software (clearing the TAEN bit). When a match occurs, the GPTM asserts the RTCRIS bit in GPTMRIS. If the RTC interrupt is enabled in GPTIMR, the GPTM also sets the RTCMIS bit in GPTMISR and generates a controller interrupt. The status flags are cleared by writing the RTCCINT bit in GPTMICR. If the TASTALL and/or TBSTALL bits in the GPTMCTL register are set, the timer does not freeze if the RTCEN bit is set in GPTMCTL.
9.2.3
16-Bit Timer Operating Modes
The GPTM is placed into global 16-bit mode by writing a value of 0x4 to the GPTM Configuration (GPTMCFG) register (see page 164). This section describes each of the GPTM 16-bit modes of operation. Timer A and Timer B have identical modes, so a single description is given using an n to reference both.
9.2.3.1
16-Bit One-Shot/Periodic Timer Mode In 16-bit one-shot and periodic timer modes, the timer is configured as a 16-bit down-counter with an optional 8-bit prescaler that effectively extends the counting range of the timer to 24 bits. The selection of one-shot or periodic mode is determined by the value written to the TnMR field of the GPTMTnMR register. The optional prescaler is loaded into the GPTM Timern Prescale (GPTMTnPR) register. When software writes the TnEN bit in the GPTMCTL register, the timer begins counting down from its preloaded value. Once the 0x0000 state is reached, the timer reloads its start value from GPTMTnILR and GPTMTnPR on the next cycle. If configured to be a one-shot timer, the timer stops counting and clears the TnEN bit in the GPTMCTL register. If configured as a periodic timer, it continues counting. In addition to reloading the count value, the timer generates interrupts and output triggers when it reaches the 0x0000 state. The GPTM sets the TnTORIS bit in the GPTMRIS register, and holds it until it is cleared by writing the GPTMICR register. If the time-out interrupt is enabled in GPTIMR, the GPTM also sets the TnTOMIS bit in GPTMISR and generates a controller interrupt. The output trigger is a one-clock-cycle pulse that is asserted when the counter hits the 0x0000 state, and deasserted on the following clock cycle. It is enabled by setting the TnOTE bit in the GPTMCTL register, and can trigger SoC-level events such as ADC conversions. If software reloads the GPTMTAILR register while the counter is running, the counter loads the new value on the next clock cycle and continues counting from the new value. If the TnSTALL bit in the GPTMCTL register is enabled, the timer freezes counting until the signal is deasserted. The following example shows a variety of configurations for a 16-bit free running timer while using the prescaler. All values assume a 25-MHz clock with Tc=20 ns (clock period).
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Table 9-1.
16-Bit Timer with Prescaler Configurations
#Clock (TC)a 1 2 3 -254 255 256 665.8458 668.4672 671.0886 mS mS mS Max Time 2.6214 5.2428 7.8642 Units mS mS mS
Prescale 00000000 00000001 00000010 -----------11111100 11111110 11111111
a. TC is the clock period.
9.2.3.2
16-Bit Input Edge Count Mode In Edge Count mode, the timer is configured as a down-counter capable of capturing three types of events: rising edge, falling edge, or both. To place the timer in Edge Count mode, the TnCMR bit of the GPTMTnMR register must be set to 0. The type of edge that the timer counts is determined by the TnEVENT fields of the GPTMCTL register. During initialization, the GPTM Timern Match (GPTMTnMATCHR) register is configured so that the difference between the value in the GPTMTnILR register and the GPTMTnMATCHR register equals the number of edge events that must be counted. When software writes the TnEN bit in the GPTM Control (GPTMCTL) register, the timer is enabled for event capture. Each input event on the CCP pin decrements the counter by 1 until the event count matches GPTMTnMATCHR. When the counts match, the GPTM asserts the CnMRIS bit in the GPTMRIS register (and the CnMMIS bit, if the interrupt is not masked). The counter is then reloaded using the value in GPTMTnILR, and stopped since the GPTM automatically clears the TnEN bit in the GPTMCTL register. Once the event count has been reached, all further events are ignored until TnEN is re-enabled by software. Figure 9-2 shows how input edge count mode works. In this case, the timer start value is set to GPTMnILR=0x000A and the match value is set to GPTMnMATCHR=0x0006 so that four edge events are counted. The counter is configured to detect both edges of the input signal. Note that the last two edges are not counted since the timer automatically clears the TnEN bit after the current count matches the value in the GPTMnMR register.
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Figure 9-2.
16-Bit Input Edge Count Mode Example
Timer reload on next cycle Ignored Ignored
Count
0x000A 0x0009 0x0008 0x0007 0x0006
Timer stops, flags asserted
Input Signal
9.2.3.3
16-Bit Input Edge Time Mode In Edge Time mode, the timer is configured as a free-running down-counter initialized to the value loaded in the GPTMTnILR register (or 0xFFFF at reset). This mode allows for event capture of both rising and falling edges. The timer is placed into Edge Time mode by setting the TnCMR bit in the GPTMTnMR register, and the type of event that the timer captures is determined by the TnEVENT fields of the GPTMCTL register. Note: Prescaler is not available in 16-Bit Input Edge Time mode. When software writes the TnEN bit in the GPTMCTL register, the timer is enabled for event capture. When the selected input event is detected, the current Tn counter value is captured in the GPTMTnR register and is available to be read by the controller. The GPTM then asserts the CnERIS bit (and the CnEMIS bit, if the interrupt is not masked). After an event has been captured, the timer does not stop counting. It continues to count until the TnEN bit is cleared. When the timer reaches the 0x0000 state, it is reloaded with the value from the GPTMnILR register. Figure 9-3 shows how input edge timing mode works. In the diagram, it is assumed that the start value of the timer is the default value of 0xFFFF, and the timer is configured to capture rising edge events. Each time a rising edge event is detected, the current count value is loaded into the GPTMTnR register, and is held there until another rising edge is detected (at which point the new count value is loaded into GPTMTnR).
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Figure 9-3.
16-Bit Input Edge Time Mode Example
Count
GPTMTnR=X GPTMTnR=Y GPTMTnR=Z
0xFFFF
Z
X
Y Time
Input Signal
9.2.3.4
16-Bit PWM Mode The GPTM supports a simple PWM generation mode. In PWM mode, the timer is configured as a down-counter with a start value (and thus period) defined by GPTMTnILR. PWM mode is enabled with the GPTMTnMR register by setting the TnAMS bit to 0x1, the TNCMR bit to 0x0, and the TnMR field to 0x2. PWM mode can take advantage of the 8-bit prescaler by using the GPTM Timern Prescale Register (GPTMTnPR) and the GPTM Timern Prescale Match Register (GPTMTnPMR). This effectively extends the range of the timer to 24 bits. When software writes the TnEN bit in the GPTMCTL register, the counter begins counting down until it reaches the 0x0000 state. On the next counter cycle, the counter reloads its start value from GPTMTnILR (and GPTMTnPR if using a prescaler) and continues counting until disabled by software clearing the TnEN bit in the GPTMCTL register. No interrupts or status bits are asserted in PWM mode. The output PWM signal asserts when the counter is at the value of the GPTMTnILR register (its start state), and is deasserted when the counter value equals the value in the GPTM Timern Match Register (GPTMnMATCHR). Software has the capability of inverting the output PWM signal by setting the TnPWML bit in the GPTMCTL register. Figure 9-4 shows how to generate an output PWM with a 1-ms period and a 66% duty cycle assuming a 50-MHz input clock and TnPWML=0 (duty cycle would be 33% for the TnPWML=1 configuration). For this example, the start value is GPTMnIRL=0xC350 and the match value is GPTMnMR=0x411A.
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Figure 9-4.
16-Bit PWM Mode Example
Count
0xC350 GPTMTnR=GPTMnMR GPTMTnR=GPTMnMR
0x411A
Time
TnEN set TnPWML = 0
Output Signal
TnPWML = 1
9.3
Initialization and Configuration
To use the general purpose timers, the peripheral clock must be enabled by setting the GPTM0, GPTM1, and GPTM2 bits in the RCGC1 register. This section shows module initialization and configuration examples for each of the supported timer modes.
9.3.1
32-Bit One-Shot/Periodic Timer Mode
The GPTM is configured for 32-bit One-Shot and Periodic modes by the following sequence: 1. Ensure the timer is disabled (the TAEN bit in the GPTMCTL register is cleared) before making any changes. 2. Write the GPTM Configuration Register (GPTMCFG) with a value of 0x0. 3. Set the TAMR field in the GPTM TimerA Mode Register (GPTMTAMR): a. Write a value of 0x1 for One-Shot mode. b. Write a value of 0x2 for Periodic mode. 4. Load the start value into the GPTM TimerA Interval Load Register (GPTMTAILR). 5. If interrupts are required, set the TATOIM bit in the GPTM Interrupt Mask Register (GPTMIMR). 6. Set the TAEN bit in the GPTMCTL register to enable the timer and start counting. 7. Poll the TATORIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the TATOCINT bit of the GPTM Interrupt Clear Register (GPTMICR).
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In One-Shot mode, the timer stops counting after step 7. To re-enable the timer, repeat the sequence. A timer configured in Periodic mode does not stop counting after it times out.
9.3.2
32-Bit Real-Time Clock (RTC) Mode
To use the RTC mode, the timer must have a 32.768-KHz input signal on its CCP0, CCP2 or CCP4 pins. To enable the RTC feature, follow these steps: 1. Ensure the timer is disabled (the TAEN bit is cleared) before making any changes. 2. Write the GPTM Configuration Register (GPTMCFG) with a value of 0x1. 3. Write the desired match value to the GPTM TimerA Match Register (GPTMTAMATCHR). 4. Set/clear the RTCEN bit in the GPTM Control Register (GPTMCTL) as desired. 5. If interrupts are required, set the RTCIM bit in the GPTM Interrupt Mask Register (GPTMIMR). 6. Set the TAEN bit in the GPTMCTL register to enable the timer and start counting. When the timer count equals the value in the GPTMTAMATCHR register, the counter is re-loaded with 0x00000000 and begins counting. If an interrupt is enabled, it does not have to be cleared.
9.3.3
16-Bit One-Shot/Periodic Timer Mode
A timer is configured for 16-bit One-Shot and Periodic modes by the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration Register (GPTMCFG) with a value of 0x4. 3. Set the TnMR field in the GPTM Timer Mode (GPTMTnMR) register: a. Write a value of 0x1 for One-Shot mode. b. Write a value of 0x2 for Periodic mode. 4. If a prescaler is to be used, write the prescale value to the GPTM Timern Prescale Register (GPTMTnPR). 5. Load the start value into the GPTM Timer Interval Load Register (GPTMTnILR). 6. If interrupts are required, set the TnTOIM bit in the GPTM Interrupt Mask Register (GPTMIMR). 7. Set the TnEN bit in the GPTM Control Register (GPTMCTL) to enable the timer and start counting. 8. Poll the TnTORIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the TnTOCINT bit of the GPTM Interrupt Clear Register (GPTMICR). In One-Shot mode, the timer stops counting after step 8. To re-enable the timer, repeat the sequence. A timer configured in Periodic mode does not stop counting after it times out.
9.3.4
16-Bit Input Edge Count Mode
A timer is configured to Input Edge Count mode by the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x4. 3. In the GPTM Timer Mode (GPTMTnMR) register, write the TnCMR field to 0x0 and the TnMR field to 0x3.
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4. Configure the type of event(s) that the timer captures by writing the TnEVENT field of the GPTM Control (GPTMCTL) register. 5. Load the timer start value into the GPTM Timern Interval Load (GPTMTnILR) register. 6. Load the desired event count into the GPTM Timern Match (GPTMTnMATCHR) register. 7. If interrupts are required, set the CnMIM bit in the GPTM Interrupt Mask (GPTMIMR) register. 8. Set the TnEN bit in the GPTMCTL register to enable the timer and begin waiting for edge events. 9. Poll the CnMRIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the CnMCINT bit of the GPTM Interrupt Clear (GPTMICR) register. In Input Edge Count Mode, the timer stops after the desired number of edge events has been detected. To re-enable the timer, ensure that the TnEN bit is cleared and repeat steps 4-9.
9.3.5
16-Bit Input Edge Timing Mode
A timer is configured to Input Edge Timing mode by the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x4. 3. In the GPTM Timer Mode (GPTMTnMR) register, write the TnCMR field to 0x1 and the TnMR field to 0x3. 4. Configure the type of event that the timer captures by writing the TnEVENT field of the GPTM Control (GPTMCTL) register. 5. Load the timer start value into the GPTM Timern Interval Load (GPTMTnILR) register. 6. If interrupts are required, set the CnEIM bit in the GPTM Interrupt Mask (GPTMIMR) register. 7. Set the TnEN bit in the GPTM Control (GPTMCTL) register to enable the timer and start counting. 8. Poll the CnERIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the CnECINT bit of the GPTM Interrupt Clear (GPTMICR) register. The time at which the event happened can be obtained by reading the GPTM Timern (GPTMTnR) register. In Input Edge Timing mode, the timer continues running after an edge event has been detected, but the timer interval can be changed at any time by writing the GPTMTnILR register. The change takes effect at the next cycle after the write.
9.3.6
16-Bit PWM Mode
A timer is configured to PWM mode using the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x4. 3. In the GPTM Timer Mode (GPTMTnMR) register, set the TnAMS bit to 0x1, the TNCMR bit to 0x0, and the TnMR field to 0x2. 4. Configure the output state of the PWM signal (whether or not it is inverted) in the TnEVENT field of the GPTM Control (GPTMCTL) register. 5. Load the timer start value into the GPTM Timern Interval Load (GPTMTnILR) register. 6. Load the GPTM Timern Match (GPTMTnMATCHR) register with the desired value.
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7. If a prescaler is going to be used, configure the GPTM Timern Prescale (GPTMTnPR) register and the GPTM Timern Prescale Match (GPTMTnPMR) register. 8. Set the TnEN bit in the GPTM Control (GPTMCTL) register to enable the timer and begin generation of the output PWM signal. In PWM Timing mode, the timer continues running after the PWM signal has been generated. The PWM period can be adjusted at any time by writing the GPTMTnILR register, and the change takes effect at the next cycle after the write.
9.4
Register Map
Table 9-1 lists the GPTM registers. The offset listed is a hexadecimal increment to the register's address, relative to that timer's base address: Timer0: 0x40030000 Timer1: 0x40031000 Timer2: 0x40032000
Table 9-2. GPTM Register Map
Offset 0x000 0x004 0x008 0x00C 0x018 0x01C 0x020 0x024 0x028 0x02C 0x030 0x034 0x038 0x03C 0x040 0x044 Name GPTMCFG GPTMTAMR GPTMTBMR GPTMCTL GPTMIMR GPTMRIS GPTMMIS GPTMICR GPTMTAILR GPTMTBILR GPTMTAMATCHR GPTMTBMATCHR GPTMTAPR GPTMTBPR GPTMTAPMR GPTMTBPMR Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x0000FFFFa 0xFFFFFFFF 0x0000FFFF 0x0000FFFFa 0xFFFFFFFF 0x0000FFFF 0x00000000 0x00000000 0x00000000 0x00000000 Type R/W R/W R/W R/W R/W RO RO W1C R/W R/W R/W R/W R/W R/W R/W R/W Description Configuration TimerA mode TimerB mode Control Interrupt mask Interrupt status Masked interrupt status Interrupt clear TimerA interval load TimerB interval load TimerA match TimerB match TimerA prescale TimerB prescale TimerA prescale match TimerB prescale match See page 164 165 166 167 169 171 172 173 174 175 176 177 178 179 180 181
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Table 9-2. GPTM Register Map (Continued)
Offset 0x048 0x04C Name GPTMTAR GPTMTBR Reset 0x0000FFFFa 0xFFFFFFFF 0x0000FFFF Type RO RO Description TimerA TimerB See page 182 183
a. The default reset value for the GPTMTAILR, GPTMTAMATCHR, and GPTMTAR registers is 0x0000FFFF when in 16-bit mode and 0xFFFFFFFF when in 32-bit mode.
9.5
Register Descriptions
The remainder of this section lists and describes the GPTM registers, in numerical order by address offset.
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Register 1: GPTM Configuration (GPTMCFG), offset 0x000 This register configures the global operation of the GPTM module. The value written to this register determines whether the GPTM is in 32- or 16-bit mode.
GPTM Configuration (GPTMCFG)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0
GPTMCFG
R/W 0 R/W 0
Bit/Field 31:3 2:0
Name reserved GPTMCFG
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM Configuration 0x0: 32-bit timer configuration. 0x1: 32-bit real-time clock (RTC) counter configuration. 0x2: Reserved. 0x3: Reserved. 0x4-0x7: 16-bit timer configuration, function is controlled by bits 1:0 of GPTMTAMR and GPTMTBMR.
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Register 2: GPTM TimerA Mode (GPTMTAMR), offset 0x004 This register configures the GPTM based on the configuration selected in the GPTMCFG register. When in 16-bit PWM mode, set the TAAMS bit to 0x1, the TACMR bit to 0x0, and the TAMR field to 0x2.
GPTM TimerA Mode (GPTMTAMR)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TAAMS TACMR
R/W 0 R/W 0 R/W 0
TAMR
R/W 0
Bit/Field 31:4 3
Name reserved TAAMS
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerA Alternate Mode Select 0: Capture mode is enabled. 1: PWM mode is enabled. Note: To enable PWM mode, you must also clear the TACMR bit and set the TAMR field to 0x2.
2
TACMR
R/W
0
GPTM TimerA Capture Mode 0: Edge-Count mode. 1: Edge-Time mode.
1:0
TAMR
R/W
0
GPTM TimerA Mode 0x0: Reserved. 0x1: One-Shot Timer mode. 0x2: Periodic Timer mode. 0x3: Capture mode. The Timer mode is based on the timer configuration defined by bits 2:0 in the GPTMCFG register (16-or 32-bit). In 16-bit timer configuration, TAMR controls the 16-bit timer modes for TimerA. In 32-bit timer configuration, this register controls the mode and the contents of GPTMTBMR are ignored.
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Register 3: GPTM TimerB Mode (GPTMTBMR), offset 0x008 This register configures the GPTM based on the configuration selected in the GPTMCFG register. When in 16-bit PWM mode, set the TBAMS bit to 0x1, the TBCMR bit to 0x0, and the TBMR field to 0x2.
GPTM TimerB Mode (GPTMTBMR)
Offset 0x008
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TBAMS TBCMR
R/W 0 R/W 0 R/W 0
TBMR
R/W 0
Bit/Field 31:4 3
Name reserved TBAMS
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB Alternate Mode Select 0: Capture mode is enabled. 1: PWM mode is enabled. Note: To enable PWM mode, you must also clear the TBCMR bit and set the TBMR field to 0x2.
2
TBCMR
R/W
0
GPTM TimerB Capture Mode 0: Edge-Count mode. 1: Edge-Time mode.
1:0
TBMR
R/W
0
GPTM TimerB Mode 0x0: Reserved. 0x1: One-Shot Timer mode. 0x2: Periodic Timer mode. 0x3: Capture mode. The timer mode is based on the timer configuration defined by bits 2:0 in the GPTMCFG register. In 16-bit timer configuration, these bits control the 16-bit timer modes for TimerB. In 32-bit timer configuration, this register's contents are ignored and GPTMTAMR is used.
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Register 4: GPTM Control (GPTMCTL), offset 0x00C This register is used alongside the GPTMCFG and GMTMTnMR registers to fine-tune the timer configuration, and to enable other features such as timer stall and the output trigger. The output trigger can be used to initiate transfers on the ADC module.
GPTM Control (GPTMCTL)
Offset 0x00C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
res
Type Reset
RO 0
TBPWML
R/W 0
TBOTE
R/W 0
res
RO 0
TBEVENT
R/W 0 R/W 0
TBSTALL
R/W 0
TBEN
R/W 0
res
RO 0
TAPWML TAOTE
R/W 0 R/W 0
RTCEN
R/W 0
TAEVENT
R/W 0 R/W 0
TASTALL
R/W 0
TAEN
R/W 0
Bit/Field 31:15 14
Name reserved TBPWML
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB PWM Output Level 0: Output is unaffected. 1: Output is inverted.
13
TBOTE
R/W
0
GPTM TimerB Output Trigger Enable 0: The output TimerB trigger is disabled. 1: The output TimerB trigger is enabled.
12 11:10
reserved TBEVENT
RO R/W
0 0
Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB Event Mode 00: Positive edge. 01: Negative edge. 10: Reserved. 11: Both edges.
9
TBSTALL
R/W
0
GPTM TimerB Stall Enable 0: TimerB stalling is disabled. 1: TimerB stalling is enabled.
8
TBEN
R/W
0
GPTM TimerB Enable 0: TimerB is disabled. 1: TimerB is enabled and begins counting or the capture logic is enabled based on the GPTMCFG register.
7
reserved
RO
0
Reserved bits return an indeterminate value, and should never be changed.
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Bit/Field 6
Name TAPWML
Type R/W
Reset 0
Description GPTM TimerA PWM Output Level 0: Output is unaffected. 1: Output is inverted.
5
TAOTE
R/W
0
GPTM TimerA Output Trigger Enable 0: The output TimerA trigger is disabled. 1: The output TimerA trigger is enabled.
4
RTCEN
R/W
0
GPTM RTC Enable 0: RTC counting is disabled. 1: RTC counting is enabled.
3:2
TAEVENT
R/W
0
GPTM TimerA Event Mode 00: Positive edge. 01: Negative edge. 10: Reserved. 11: Both edges.
1
TASTALL
R/W
0
GPTM TimerA Stall Enable 0: TimerA stalling is disabled. 1: TimerA stalling is enabled.
0
TAEN
R/W
0
GPTM TimerA Enable 0: TimerA is disabled. 1: TimerA is enabled and begins counting or the capture logic is enabled based on the GPTMCFG register.
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LM3S317 Data Sheet
Register 5: GPTM Interrupt Mask (GPTMIMR), offset 0x018 This register allows software to enable/disable GPTM controller-level interrupts. Writing a 1 enables the interrupt, while writing a 0 disables it.
GPTM Interrupt Mask (GPTMIMR)
Offset 0x018
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
CBEIM CBMIM TBTOIM
R/W 0 R/W 0 R/W 0 RO 0
reserved
RO 0 RO 0 RO 0
RTCIM
R/W 0
CAEIM CAMIM TATOIM
R/W 0 R/W 0 R/W 0
Bit/Field 31:11 10
Name reserved CBEIM
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM CaptureB Event Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
9
CBMIM
R/W
0
GPTM CaptureB Match Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
8
TBTOIM
R/W
0
GPTM TimerB Time-Out Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
7:4 3
reserved RTCIM
RO R/W
0 0
Reserved bits return an indeterminate value, and should never be changed. GPTM RTC Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
2
CAEIM
R/W
0
GPTM CaptureA Event Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
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General-Purpose Timers
Bit/Field 1
Name CAMIM
Type R/W
Reset 0
Description GPTM CaptureA Match Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
0
TATOIM
R/W
0
GPTM TimerA Time-Out Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled.
170 Preliminary
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LM3S317 Data Sheet
Register 6: GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C This register shows the state of the GPTM's internal interrupt signal. These bits are set whether or not the interrupt is masked in the GPTMIMR register. Each bit can be cleared by writing a 1 to its corresponding bit in GPTMICR.
GPTM Raw Interrupt Status (GPTMRIS)
Offset 0x01C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
CBERIS
RO 0
CBMRIS TBTORIS
RO 0 RO 0 RO 0
reserved
RO 0 RO 0 RO 0
RTCRIS
RO 0
CAERIS
RO 0
CAMRIS TATORIS
RO 0 RO 0
Bit/Field 31:11 10
Name reserved CBERIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM CaptureB Event Raw Interrupt This is the CaptureB Event interrupt status prior to masking.
9
CBMRIS
RO
0
GPTM CaptureB Match Raw Interrupt This is the CaptureB Match interrupt status prior to masking.
8
TBTORIS
RO
0
GPTM TimerB Time-Out Raw Interrupt This is the TimerB time-out interrupt status prior to masking.
7:4 3
reserved RTCRIS
RO RO
0 0
Reserved bits return an indeterminate value, and should never be changed. GPTM RTC Raw Interrupt This is the RTC Event interrupt status prior to masking.
2
CAERIS
RO
0
GPTM CaptureA Event Raw Interrupt This is the CaptureA Event interrupt status prior to masking.
1
CAMRIS
RO
0
GPTM CaptureA Match Raw Interrupt This is the CaptureA Match interrupt status prior to masking.
0
TATORIS
RO
0
GPTM TimerA Time-Out Raw Interrupt This the TimerA time-out interrupt status prior to masking.
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171
General-Purpose Timers
Register 7: GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 This register show the state of the GPTM's controller-level interrupt. If an interrupt is unmasked in GPTMIMR, and there is an event that causes the interrupt to be asserted, the corresponding bit is set in this register. All bits are cleared by writing a 1 to the corresponding bit in GPTMICR.
GPTM Masked Interrupt Status (GPTMMIS)
Offset 0x020
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
CBEMIS
RO 0
CBMMIS TBTOMIS
RO 0 RO 0 RO 0
reserved
RO 0 RO 0 RO 0
RTCMIS
RO 0
CAEMIS CAMMIS TATOMIS
RO 0 RO 0 RO 0
Bit/Field 31:11 10
Name reserved CBEMIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM CaptureB Event Masked Interrupt This is the CaptureB event interrupt status after masking.
9
CBMMIS
RO
0
GPTM CaptureB Match Masked Interrupt This is the CaptureB match interrupt status after masking.
8
TBTOMIS
RO
0
GPTM TimerB Time-Out Masked Interrupt This is the TimerB time-out interrupt status after masking.
7:4 3
reserved RTCMIS
RO RO
0 0
Reserved bits return an indeterminate value, and should never be changed. GPTM RTC Masked Interrupt This is the RTC event interrupt status after masking.
2
CAEMIS
RO
0
GPTM CaptureA Event Masked Interrupt This is the CaptureA event interrupt status after masking.
1
CAMMIS
RO
0
GPTM CaptureA Match Masked Interrupt This is the CaptureA match interrupt status after masking.
0
TATOMIS
RO
0
GPTM TimerA Time-Out Masked Interrupt This is the TimerA time-out interrupt status after masking.
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LM3S317 Data Sheet
Register 8: GPTM Interrupt Clear (GPTMICR), offset 0x024 This register is used to clear the status bits in the GPTMRIS and GPTMMIS registers. Writing a 1 to a bit clears the corresponding bit in the GPTMRIS and GPTMMIS registers.
GPTM Interrupt Clear (GPTMICR)
Offset 0x024
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 W1C 0
CBECINT CBMCINT TBTOCINT
W1C 0 W1C 0 W1C 0 RO 0 RO 0
reserved
RO 0 RO 0
RTCCINT CAECINT CAMCINTTATOCINT
W1C 0 W1C 0 W1C 0 W1C 0
Bit/Field 31:11 10
Name reserved CBECINT
Type RO W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM CaptureB Event Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared.
9
CBMCINT
W1C
0
GPTM CaptureB Match Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared.
8
TBTOCINT
W1C
0
GPTM TimerB Time-Out Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared.
7:4 3
reserved RTCCINT
RO W1C
0 0
Reserved bits return an indeterminate value, and should never be changed. GPTM RTC Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared.
2
CAECINT
W1C
0
GPTM CaptureA Event Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared.
1
CAMCINT
W1C
0
GPTM CaptureA Match Raw Interrupt This is the CaptureA match interrupt status after masking.
0
TATOCINT
W1C
0
GPTM TimerA Time-Out Raw Interrupt 0: The interrupt is unaffected. 1: The interrupt is cleared.
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General-Purpose Timers
Register 9: GPTM TimerA Interval Load (GPTMTAILR), offset 0x028 This register is used to load the starting count value into the timer. When GPTM is configured to one of the 32-bit modes, GPTMTAILR appears as a 32-bit register (the upper 16-bits correspond to the contents of the GPTM TimerB Interval Load (GPTMTBILR) register). In 16-bit mode, the upper 16 bits of this register read as 0s and have no effect on the state of GPTMTBILR.
GPTM TimerA Interval Load (GPTMTAILR)
Offset 0x028
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
TAILRH
Type Reset
R/W 1/0 15 R/W 1/0 14 R/W 1/0 13 R/W 1/0 12 R/W 1/0 11 R/W 1/0 10 R/W 1/0 9 R/W 1/0 8 R/W 1/0 7 R/W 1/0 6 R/W 1/0 5 R/W 1/0 4 R/W 1/0 3 R/W 1/0 2 R/W 1/0 1 R/W 1/0 0
TAILRL
Type Reset
R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1
1/0 = 1 if timer is configured in 32-bit mode; 0 if timer is configured in 16-bit mode.
Bit/Field 31:16
Name TAILRH
Type R/W
Reset 0xFFFF (32-bit mode) 0x0000 (16-bit mode)
Description GPTM TimerA Interval Load Register High When configured for 32-bit mode via the GPTMCFG register, the GPTM TimerB Interval Load (GPTMTBILR) register loads this value on a write. A read returns the current value of GPTMTBILR. In 16-bit mode, this field reads as 0 and does not have an effect on the state of GPTMTBILR. GPTM TimerA Interval Load Register Low For both 16- and 32-bit modes, writing this field loads the counter for TimerA. A read returns the current value of GPTMTAILR.
15:0
TAILRL
R/W
0xFFFF
174 Preliminary
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LM3S317 Data Sheet
Register 10: GPTM TimerB Interval Load (GPTMTBILR), offset 0x02C This register is used to load the starting count value into TimerB. When the GPTM is configured to a 32-bit mode, GPTMTBILR returns the current value of TimerB and ignores writes.
GPTM TimerB Interval Load (GPTMTBILR)
Offset 0x02C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
TBILRL
Type Reset
R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1
Bit/Field 31:16 15:0
Name reserved TBILRL
Type RO R/W
Reset 0 0xFFFF
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB Interval Load Register When the GPTM is not configured as a 32-bit timer, a write to this field updates GPTMTBILR. In 32-bit mode, writes are ignored, and reads return the current value of GPTMTBILR.
May 4, 2007 Preliminary
175
General-Purpose Timers
Register 11: GPTM TimerA Match (GPTMTAMATCHR), offset 0x030 This register is used in 32-bit Real-Time Clock mode and 16-bit PWM and Input Edge Count modes.
GPTM TimerA Match (GPTMTAMATCHR)
Offset 0x030
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
TAMRH
Type Reset
R/W 1/0 15 R/W 1/0 14 R/W 1/0 13 R/W 1/0 12 R/W 1/0 11 R/W 1/0 10 R/W 1/0 9 R/W 1/0 8 R/W 1/0 7 R/W 1/0 6 R/W 1/0 5 R/W 1/0 4 R/W 1/0 3 R/W 1/0 2 R/W 1/0 1 R/W 1/0 0
TAMRL
Type Reset
R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1
1/0 = 1 if timer is configured in 32-bit mode; 0 if timer is configured in 16-bit mode.
Bit/Field 31:16
Name TAMRH
Type R/W
Reset 0xFFFF (32-bit mode) 0x0000 (16-bit mode)
Description GPTM TimerA Match Register High When configured for 32-bit Real-Time Clock (RTC) mode via the GPTMCFG register, this value is compared to the upper half of GPTMTAR, to determine match events. In 16-bit mode, this field reads as 0 and does not have an effect on the state of GPTMTBMATCHR. GPTM TimerA Match Register Low When configured for 32-bit Real-Time Clock (RTC) mode via the GPTMCFG register, this value is compared to the lower half of GPTMTAR, to determine match events. When configured for PWM mode, this value along with GPTMTAILR, determines the duty cycle of the output PWM signal. When configured for Edge Count mode, this value along with GPTMTAILR, determines how many edge events are counted. The total number of edge events counted is equal to the value in GPTMTAILR minus this value.
15:0
TAMRL
R/W
0xFFFF
176 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 12: GPTM TimerB Match (GPTMTBMATCHR), offset 0x034 This register is used in 32-bit Real-Time Clock mode and 16-bit PWM and Input Edge Count modes.
GPTM TimerB Match (GPTMTBMATCHR)
Offset 0x034
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
TBMRL
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:0
Name reserved TBMRL
Type RO R/W
Reset 0 0xFFFF
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB Match Register Low When configured for PWM mode, this value along with GPTMTBILR, determines the duty cycle of the output PWM signal. When configured for Edge Count mode, this value along with GPTMTBILR, determines how many edge events are counted. The total number of edge events counted is equal to the value in GPTMTBILR minus this value.
May 4, 2007 Preliminary
177
General-Purpose Timers
Register 13: GPTM TimerA Prescale (GPTMTAPR), offset 0x038 This register allows software to extend the range of the 16-bit timers.
GPTM TimerA Prescale (GPTMTAPR)
Offset 0x038
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
TAPSR
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved TAPSR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerA Prescale The register loads this value on a write. A read returns the current value of the register. Refer to Table 9-1 on page 156 for more details and an example.
178 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 14: GPTM TimerB Prescale (GPTMTBPR), offset 0x03C This register allows software to extend the range of the 16-bit timers.
GPTM TimerB Prescale (GPTMTBPR)
Offset 0x03C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0
TBPSR
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved TBPSR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB Prescale The register loads this value on a write. A read returns the current value of this register. Refer to Table 9-1 on page 156 for more details and an example.
May 4, 2007 Preliminary
179
General-Purpose Timers
Register 15: GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040 This register effectively extends the range of GPTMTAMATCHR to 24 bits.
GPTM TimerA Prescale Match (GPTMTAPMR)
Offset 0x040
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0
TAPSMR
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved TAPSMR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerA Prescale Match This value is used alongside GPTMTAMATCHR to detect timer match events while using a prescaler.
180 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 16: GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044 This register effectively extends the range of GPTMTBMATCHR to 24 bits.
GPTM TimerB Prescale Match (GPTMTBPMR)
Offset 0x044
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0
TBPSMR
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved TBPSMR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB Prescale Match This value is used alongside GPTMTBMATCHR to detect timer match events while using a prescaler.
May 4, 2007 Preliminary
181
General-Purpose Timers
Register 17: GPTM TimerA (GPTMTAR), offset 0x048 This register shows the current value of the TimerA counter in all cases except for Input Edge Count mode. When in this mode, this register contains the time at which the last edge event took place.
GPTM TimerA (GPTMTAR)
Offset 0x048
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
TARH
Type Reset
RO 1/0 15 RO 1/0 14 RO 1/0 13 RO 1/0 12 RO 1/0 11 RO 1/0 10 RO 1/0 9 RO 1/0 8 RO 1/0 7 RO 1/0 6 RO 1/0 5 RO 1/0 4 RO 1/0 3 RO 1/0 2 RO 1/0 1 RO 1/0 0
TARL
Type Reset
RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1
1/0 = 1 if timer is configured in 32-bit mode; 0 if timer is configured in 16-bit mode.
Bit/Field 31:16
Name TARH
Type RO
Reset 0xFFFF (32-bit mode) 0x0000 (16-bit mode)
Description GPTM TimerA Register High If the GPTMCFG is in a 32-bit mode, TimerB value is read. If the GPTMCFG is in a 16-bit mode, this is read as zero.
15:0
TARL
RO
0xFFFF
GPTM TimerA Register Low A read returns the current value of the GPTM TimerA Count Register, except in Input Edge Count mode, when it returns the timestamp from the last edge event.
182 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 18: GPTM TimerB (GPTMTBR), offset 0x04C This register shows the current value of the TimerB counter in all cases except for Input Edge Count mode. When in this mode, this register contains the time at which the last edge event took place.
GPTM TimerB (GPTMTBR)
Offset 0x04C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
TBRL
Type Reset
RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1
Bit/Field 31:16 15:0
Name reserved TBRL
Type RO RO
Reset 0 0xFFFF
Description Reserved bits return an indeterminate value, and should never be changed. GPTM TimerB A read returns the current value of the GPTM TimerB Count Register, except in Input Edge Count mode, when it returns the timestamp from the last edge event.
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183
Watchdog Timer
10
Watchdog Timer
A watchdog timer can generate nonmaskable interrupts (NMIs) or a reset when a time-out value is reached. The watchdog timer is used to regain control when a system has failed due to a software error or due to the failure of an external device to respond in the expected way. The Stellaris Watchdog Timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, a locking register, and user-enabled stalling. The Watchdog Timer can be configured to generate an interrupt to the controller on its first time-out, and to generate a reset signal on its second time-out. Once the Watchdog Timer has been configured, the lock register can be written to prevent the timer configuration from being inadvertently altered.
10.1
Block Diagram
Figure 10-1. WDT Module Block Diagram
Control / Clock / Interrupt Generation WDTCTL WDTICR Interrupt WDTRIS WDTMIS WDTLOCK System Clock WDTTEST Comparator WDTVALUE 32-Bit Down Counter 0x00000000 WDTLOAD
Identification Registers WDTPCellID0 WDTPCellID1 WDTPCellID2 WDTPCellID3 WDTPeriphID0 WDTPeriphID1 WDTPeriphID2 WDTPeriphID3 WDTPeriphID4 WDTPeriphID5 WDTPeriphID6 WDTPeriphID7
184 Preliminary
May 4, 2007
LM3S317 Data Sheet
10.2
Functional Description
The Watchdog Timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, and a locking register. Once the Watchdog Timer has been configured, the Watchdog Timer Lock (WDTLOCK) register is written, which prevents the timer configuration from being inadvertently altered by software. The Watchdog Timer module generates the first time-out signal when the 32-bit counter reaches the zero state after being enabled; enabling the counter also enables the watchdog timer interrupt. After the first time-out event, the 32-bit counter is re-loaded with the value of the Watchdog Timer Load (WDTLOAD) register, and the timer resumes counting down from that value. If the timer counts down to its zero state again before the first time-out interrupt is cleared, and the reset signal has been enabled (via the WatchdogResetEnable function), the Watchdog timer asserts its reset signal to the system. If the interrupt is cleared before the 32-bit counter reaches its second time-out, the 32-bit counter is loaded with the value in the WDTLOAD register, and counting resumes from that value. If WDTLOAD is written with a new value while the Watchdog Timer counter is counting, then the counter is loaded with the new value and continues counting. Writing to WDTLOAD does not clear an active interrupt. An interrupt must be specifically cleared by writing to the Watchdog Interrupt Clear (WDTICR) register. The Watchdog module interrupt and reset generation can be enabled or disabled as required. When the interrupt is re-enabled, the 32-bit counter is preloaded with the load register value and not its last state.
10.3
Initialization and Configuration
To use the WDT, its peripheral clock must be enabled by setting the WDT bit in the RCGC0 register. The Watchdog Timer is configured using the following sequence: 1. Load the WDTLOAD register with the desired timer load value. 2. If the Watchdog is configured to trigger system resets, set the RESEN bit in the WDTCTL register. 3. Set the INTEN bit in the WDTCTL register to enable the Watchdog and lock the control register. If software requires that all of the watchdog registers are locked, the Watchdog Timer module can be fully locked by writing any value to the WDTLOCK register. To unlock the Watchdog Timer, write a value of 0x1ACCE551.
10.4
Register Map
Table 10-1 lists the Watchdog registers. The offset listed is a hexadecimal increment to the register's address, relative to the Watchdog Timer base address of 0x40000000.
Table 10-1.
Offset 0x000 0x004 0x008
WDT Register Map
Name WDTLOAD WDTVALUE WDTCTL Reset 0xFFFFFFFF 0xFFFFFFFF 0x00000000 Type R/W RO R/W Description Load Current value Control See page 187 188 189
May 4, 2007 Preliminary
185
Watchdog Timer
Table 10-1.
Offset 0x00C 0x010 0x014 0x418 0xC00 0xFD0 0xFD4 0xFD8 0xFDC 0xFE0 0xFE4 0xFE8 0xFEC 0xFF0 0xFF4 0xFF8 0xFFC
WDT Register Map (Continued)
Name WDTICR WDTRIS WDTMIS WDTTEST WDTLOCK WDTPeriphID4 WDTPeriphID5 WDTPeriphID6 WDTPeriphID7 WDTPeriphID0 WDTPeriphID1 WDTPeriphID2 WDTPeriphID3 WDTPCellID0 WDTPCellID1 WDTPCellID2 WDTPCellID3 Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000005 0x00000018 0x00000018 0x00000001 0x0000000D 0x000000F0 0x00000005 0x000000B1 Type WO RO RO R/W R/W RO RO RO RO RO RO RO RO RO RO RO RO Description Interrupt clear Raw interrupt status Masked interrupt status Watchdog stall enable Lock Peripheral identification 4 Peripheral identification 5 Peripheral identification 6 Peripheral identification 7 Peripheral identification 0 Peripheral identification 1 Peripheral identification 2 Peripheral identification 3 PrimeCell identification 0 PrimeCell identification 1 PrimeCell identification 2 PrimeCell identification 3 See page 190 191 192 194 193 195 196 197 198 199 200 201 202 203 204 205 206
10.5
Register Descriptions
The remainder of this section lists and describes the WDT registers, in numerical order by address offset.
186 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 1: Watchdog Load (WDTLOAD), offset 0x000 This register is the 32-bit interval value used by the 32-bit counter. When this register is written, the value is immediately loaded and the counter restarts counting down from the new value. If the WDTLOAD register is loaded with 0x00000000, an interrupt is immediately generated.
Watchdog Load (WDTLOAD)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
WDTLoad
Type Reset
R/W 1 15 R/W 1 14 R/W 1 13 R/W 1 12 R/W 1 11 R/W 1 10 R/W 1 9 R/W 1 8 R/W 1 7 R/W 1 6 R/W 1 5 R/W 1 4 R/W 1 3 R/W 1 2 R/W 1 1 R/W 1 0
WDTLoad
Type Reset
R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1
Bit/Field 31:0
Name WDTLoad
Type R/W
Reset 0xFFFFFFFF
Description Watchdog Load Value
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187
Watchdog Timer
Register 2: Watchdog Value (WDTVALUE), offset 0x004 This register contains the current count value of the timer.
Watchdog Value (WDTVALUE)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
WDTValue
Type Reset
RO 1 15 RO 1 14 RO 1 13 RO 1 12 RO 1 11 RO 1 10 RO 1 9 RO 1 8 RO 1 7 RO 1 6 RO 1 5 RO 1 4 RO 1 3 RO 1 2 RO 1 1 RO 1 0
WDTValue
Type Reset
RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1
Bit/Field 31:0
Name WDTValue
Type RO
Reset 0xFFFFFFFF
Description Watchdog Value Current value of the 32-bit down counter.
188 Preliminary
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LM3S317 Data Sheet
Register 3: Watchdog Control (WDTCTL), offset 0x008 This register is the watchdog control register. The watchdog timer can be configured to generate a reset signal (upon second time-out) or an interrupt on time-out. When the watchdog interrupt has been enabled, all subsequent writes to the control register are ignored. The only mechanism that can re-enable writes is a hardware reset.
Watchdog Control (WDTCTL)
Offset 0x008
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
RESEN
R/W 0
INTEN
R/W 0
Bit/Field 31:2 1
Name reserved RESEN
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Reset Enable 0: Disabled. 1: Enable the Watchdog module reset output.
0
INTEN
R/W
0
Watchdog Interrupt Enable 0: Interrupt event disabled (once this bit is set, it can only be cleared by a hardware reset) 1: Interrupt event enabled. Once enabled, all writes are ignored.
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Watchdog Timer
Register 4: Watchdog Interrupt Clear (WDTICR), offset 0x00C This register is the interrupt clear register. A write of any value to this register clears the Watchdog interrupt and reloads the 32-bit counter from the WDTLOAD register. Value for a read or reset is indeterminate.
Watchdog Interrupt Clear (WDTICR)
Offset 0x00C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
WDTIntClr
Type Reset
WO 15 WO 14 WO 13 WO 12 WO 11 WO 10 WO 9 WO 8 WO 7 WO 6 WO 5 WO 4 WO 3 WO 2 WO 1 WO 0
WDTIntClr
Type Reset
WO WO WO WO WO WO WO WO WO WO WO WO WO WO WO WO -
Bit/Field 31:0
Name WDTIntClr
Type WO
Reset -
Description Watchdog Interrupt Clear
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LM3S317 Data Sheet
Register 5: Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 This register is the raw interrupt status register. Watchdog interrupt events can be monitored via this register if the controller interrupt is masked.
Watchdog Raw Interrupt Status (WDTRIS)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
WDTRIS
RO 0
Bit/Field 31:1 0
Name reserved WDTRIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Raw Interrupt Status Gives the raw interrupt state (prior to masking) of WDTINTR.
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Watchdog Timer
Register 6: Watchdog Masked Interrupt Status (WDTMIS), offset 0x014 This register is the masked interrupt status register. The value of this register is the logical AND of the raw interrupt bit and the Watchdog interrupt enable bit.
Watchdog Masked Interrupt Status (WDTMIS)
Offset 0x014
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
WDTMIS
RO 0
Bit/Field 31:1 0
Name reserved WDTMIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Masked Interrupt Status Gives the masked interrupt state (after masking) of the WDTINTR interrupt.
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LM3S317 Data Sheet
Register 7: Watchdog Lock (WDTLOCK), offset 0xC00 Writing 0x1ACCE551 to the WDTLOCK register enables write access to all other registers. Writing any other value to the WDTLOCK register re-enables the locked state for register writes to all the other registers. Reading the WDTLOCK register returns the lock status rather than the 32-bit value written. Therefore, when write accesses are disabled, reading the WDTLOCK register returns 0x00000001 (when locked; otherwise, the returned value is 0x00000000 (unlocked)).
Watchdog Lock (WDTLOCK)
Offset 0xC00
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
WDTLock
Type Reset
R/W 0 15 R/W 0 14 R/W 0 13 R/W 0 12 R/W 0 11 R/W 0 10 R/W 0 9 R/W 0 8 R/W 0 7 R/W 0 6 R/W 0 5 R/W 0 4 R/W 0 3 R/W 0 2 R/W 0 1 R/W 0 0
WDTLock
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:0
Name WDTLock
Type R/W
Reset 0x0000
Description Watchdog Lock A write of the value 0x1ACCE551 unlocks the watchdog registers for write access. A write of any other value reapplies the lock, preventing any register updates. A read of this register returns the following values: Locked: 0x00000001 Unlocked: 0x00000000
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Watchdog Timer
Register 8: Watchdog Test (WDTTEST), offset 0x418 This register provides user-enabled stalling when the microcontroller asserts the CPU halt flag during debug.
Watchdog Test (WDTTEST)
Offset 0x418
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
STALL
R/W 0 RO 0 RO 0 RO 0
reserved
RO 0 RO 0 RO 0 RO 0 RO 0
Bit/Field 31:9 8
Name reserved STALL
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Stall Enable When set to 1, if the Stellaris microcontroller is stopped with a debugger, the watchdog timer stops counting. Once the microcontroller is restarted, the watchdog timer resumes counting.
7:0
reserved
RO
0
Reserved bits return an indeterminate value, and should never be changed.
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LM3S317 Data Sheet
Register 9: Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 4 (WDTPeriphID4)
Offset 0xFD0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID4
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID4
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. WDT Peripheral ID Register[7:0]
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Watchdog Timer
Register 10: Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 5 (WDTPeriphID5)
Offset 0xFD4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID5
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID5
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. WDT Peripheral ID Register[15:8]
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LM3S317 Data Sheet
Register 11: Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 6 (WDTPeriphID6)
Offset 0xFD8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID6
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID6
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. WDT Peripheral ID Register[23:16]
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Watchdog Timer
Register 12: Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 7 (WDTPeriphID7)
Offset 0xFDC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID7
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID7
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. WDT Peripheral ID Register[31:24]
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LM3S317 Data Sheet
Register 13: Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 0 (WDTPeriphID0)
Offset 0xFE0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID0
RO 0 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID0
Type RO RO
Reset 0 0x05
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Peripheral ID Register[7:0]
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199
Watchdog Timer
Register 14: Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 1 (WDTPeriphID1)
Offset 0xFE4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1
PID1
RO 1 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID1
Type RO RO
Reset 0 0x18
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Peripheral ID Register[15:8]
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LM3S317 Data Sheet
Register 15: Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 2 (WDTPeriphID2)
Offset 0xFE8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1
PID2
RO 1 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID2
Type RO RO
Reset 0 0x18
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Peripheral ID Register[23:16]
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201
Watchdog Timer
Register 16: Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Peripheral Identification 3 (WDTPeriphID3)
Offset 0xFEC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID3
Type RO RO
Reset 0 0x01
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog Peripheral ID Register[31:24]
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LM3S317 Data Sheet
Register 17: Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0 The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Primecell Identification 0 (WDTPCellID0)
Offset 0xFF0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID0
RO 1 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID0
Type RO RO
Reset 0 0x0D
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog PrimeCell ID Register[7:0]
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203
Watchdog Timer
Register 18: Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4 The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Primecell Identification 1 (WDTPCellID1)
Offset 0xFF4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 1
CID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved CID1
Type RO RO
Reset 0 0xF0
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog PrimeCell ID Register[15:8]
204 Preliminary
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LM3S317 Data Sheet
Register 19: Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8 The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Primecell Identification 2 (WDTPCellID2)
Offset 0xFF8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID2
RO 0 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID2
Type RO RO
Reset 0 0x05
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog PrimeCell ID Register[23:16]
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205
Watchdog Timer
Register 20: Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value.
Watchdog Primecell Identification 3 (WDTPCellID3)
Offset 0xFFC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 RO 1
CID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID3
Type RO RO
Reset 0 0xB1
Description Reserved bits return an indeterminate value, and should never be changed. Watchdog PrimeCell ID Register[31:24]
206 Preliminary
May 4, 2007
LM3S317 Data Sheet
11
Analog-to-Digital Converter (ADC)
An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a discrete digital number. The Stellaris ADC module features 10-bit conversion resolution and supports six input channels, plus an internal temperature sensor. The ADC module contains a programmable sequencer which allows for the sampling of multiple analog input sources without controller intervention. Each sample sequence provides flexible programming with fully configurable input source, trigger events, interrupt generation, and sequence priority. The Stellaris ADC provides the following features: Six analog input channels Single-ended and differential-input configurations Internal temperature sensor Sample rate of 250 thousand samples/second Four programmable sample conversion sequences from one to eight entries long, with corresponding conversion result FIFOs Flexible trigger control - Controller (software) - Timers - Analog Comparator - PWM - GPIO Hardware averaging of up to 64 samples for improved accuracy
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Analog-to-Digital Converter (ADC)
11.1
Block Diagram
Figure 11-1.
Comparator GPIO (PB4) Timer PWM Comparator GPIO (PB4) Timer PWM Comparator GPIO (PB4) Timer PWM Comparator GPIO (PB4) Timer PWM
ADC Module Block Diagram
Sample Sequencer 0 ADCSSMUX0 ADCSSCTL0 ADCSSFSTAT0 Sample Sequencer 1 ADCSSMUX1 SS1 ADCSSCTL1 ADCSSFSTAT1 Sample Sequencer 2 ADCSSMUX2 ADCSSCTL2 ADCSSFSTAT2 ADCEMUX ADCPSSI Interrupt Control ADCIM ADCRIS ADCISC Sample Sequencer 3 ADCSSMUX3 ADCSSCTL3 ADCSSFSTAT3 FIFO Block ADCSSFIFO0 ADCSSFIFO1 ADCSSFIFO2 ADCSSFIFO3 Hardware Averager ADCSAC Analog-to-Digital Converter
Trigger Events Control/Status SS3 ADCACTSS ADCOSTAT ADCUSTAT SS2 ADCSSPRI
SS0
SS0 Interrupt SS1 Interrupt SS2 Interrupt SS3 Interrupt
11.2
Functional Description
The Stellaris ADC collects sample data by using a programmable sequence-based approach instead of the traditional single or double-sampling approach found on many ADC modules. Each sample sequence is a fully programmed series of consecutive (back-to-back) samples, allowing the ADC to collect data from multiple input sources without having to be re-configured or serviced by the controller. The programming of each sample in the sample sequence includes parameters such as the input source and mode (differential versus single-ended input), interrupt generation on sample completion, and the indicator for the last sample in the sequence.
11.2.1
Sample Sequencers
The sampling control and data capture is handled by the Sample Sequencers. All of the sequencers are identical in implementation except for the number of samples that can be captured and the depth of the FIFO. Table 11-1 shows the maximum number of samples that each Sequencer can capture and its corresponding FIFO depth. In this implementation, each FIFO entry is a 32-bit word, with the lower 10 bits containing the conversion result. Table 11-1.
Sequencer SS3 SS2 SS1 SS0
Samples and FIFO Depth of Sequencers
Number of Samples 1 4 4 8 Depth of FIFO 1 4 4 8
208 Preliminary
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LM3S317 Data Sheet
For a given sample sequence, each sample is defined by two 4-bit nibbles in the ADC Sample Sequence Input Multiplexer Select (ADCSSMUXn) and ADC Sample Sequence Control (ADCSSCTLn) registers, where "n" corresponds to the sequence number. The ADCSSMUXn nibbles select the input pin, while the ADCSSCTLn nibbles contain the sample control bits corresponding to parameters such as temperature sensor selection, interrupt enable, end of sequence, and differential input mode. Sample Sequencers are enabled by setting the respective ASENn bit in the ADC Active Sample Sequencer (ADCACTSS) register, but can be configured before being enabled. When configuring a sample sequence, multiple uses of the same input pin within the same sequence is allowed. In the ADCSSCTLn register, the Interrupt Enable (IE) bits can be set for any combination of samples, allowing interrupts to be generated after every sample in the sequence if necessary. Also, the END bit can be set at any point within a sample sequence. For example, if Sequencer 0 is used, the END bit can be set in the nibble associated with the fifth sample, allowing Sequencer 0 to complete execution of the sample sequence after the fifth sample. After a sample sequence completes execution, the result data can be retrieved from the ADC Sample Sequence Result FIFO (ADCSSFIFOn) registers. The FIFOs are simple circular buffers that read a single address to "pop" result data. For software debug purposes, the positions of the FIFO head and tail pointers are visible in the ADC Sample Sequence FIFO Status (ADCSSFSTATn) registers along with FULL and EMPTY status flags. Overflow and underflow conditions are monitored using the ADCOSTAT and ADCUSTAT registers.
11.2.2
Module Control
Outside of the Sample Sequencers, the remainder of the control logic is responsible for tasks such as interrupt generation, sequence prioritization, and trigger configuration. Most of the ADC control logic runs at the ADC clock rate of 14-18 MHz. The internal ADC divider is configured automatically by hardware when the system XTAL is selected. The automatic clock divider configuration targets 16.667 MHz operation for all Stellaris devices.
11.2.2.1
Interrupts The Sample Sequencers dictate the events that cause interrupts, but they don't have control over whether the interrupt is actually sent to the interrupt controller. The ADC module's interrupt signal is controlled by the state of the MASK bits in the ADC Interrupt Mask (ADCIM) register. Interrupt status can be viewed at two locations: the ADC Raw Interrupt Status (ADCRIS) register, which shows the raw status of a Sample Sequencer's interrupt signal, and the ADC Interrupt Status and Clear (ADCISC) register, which shows the logical AND of the ADCRIS register's INR bit and the ADCIM register's MASK bits. Interrupts are cleared by writing a 1 to the corresponding IN bit in ADCISC.
11.2.2.2
Prioritization When sampling events (triggers) happen concurrently, they are prioritized for processing by the values in the ADC Sample Sequencer Priority (ADCSSPRI) register. Valid priority values are in the range of 0-3, with 0 being the highest priority and 3 being the lowest. Multiple active Sample Sequencer units with the same priority do not provide consistent results, so software must ensure that all active Sample Sequencer units have a unique priority value.
11.2.2.3
Sampling Events Sample triggering for each Sample Sequencer is defined in the ADC Event Multiplexer Select (ADCEMUX) register. The external peripheral triggering sources vary by Stellaris family member, but all devices share the "Controller" and "Always" triggers. Software can initiate sampling by setting the CH bits in the ADC Processor Sample Sequence Initiate (ADCPSSI) register.
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Analog-to-Digital Converter (ADC)
When using the "Always" trigger, care must be taken. If a sequence's priority is too high, it is possible to starve other lower priority sequences.
11.2.3
Hardware Sample Averaging Circuit
Higher precision results can be generated using the hardware averaging circuit, however, the improved results are at the cost of throughput. Up to 64 samples can be accumulated and averaged to form a single data entry in the sequencer FIFO. Throughput is decreased proportionally to the number of samples in the averaging calculation. For example, if the averaging circuit is configured to average 16 samples, the throughput is decreased by a factor of 16. By default the averaging circuit is off and all data from the converter passes through to the sequencer FIFO. The averaging hardware is controlled by the ADC Sample Averaging Control (ADCSAC) register (see page 222). There is a single averaging circuit and all input channels receive the same amount of averaging whether they are single-ended or differential.
11.2.4
Analog-to-Digital Converter
The converter itself generates a 10-bit output value for selected analog input. Special analog pads are used to minimize the distortion on the input.
11.2.5
Test Modes
There is a user-available test mode that allows for loopback operation within the digital portion of the ADC module. This can be useful for debugging software without having to provide actual analog stimulus. This mode is available through the ADC Test Mode Loopback (ADCTMLB) register (see page 235).
11.2.6
Internal Temperature Sensor
The internal temperature sensor provides an analog temperature reading as well as a reference voltage. The voltage at the output terminal SENSO is given by the following equation:
SENSO = 2.7 - ((T + 55) / 75)
This relation is shown in Figure 11-2 on page 210. Figure 11-2. Internal Temperature Sensor Characteristic
11.3
Initialization and Configuration
In order for the ADC module to be used, the PLL must be enabled and using a supported crystal frequency (see the RCC register on page 83). Using unsupported frequencies can cause faulty operation in the ADC module.
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LM3S317 Data Sheet
11.3.1
Module Initialization
Initialization of the ADC module is a simple process with very few steps. The main steps include enabling the clock to the ADC and reconfiguring the Sample Sequencer priorities (if needed). The initialization sequence for the ADC is as follows: 1. Enable the ADC clock by writing a value of 0x00010000 to the RCGC1 register in the System Control module. 2. If required by the application, reconfigure the Sample Sequencer priorities in the ADCSSPRI register. The default configuration has Sample Sequencer 0 with the highest priority, and Sample Sequencer 3 as the lowest priority.
11.3.2
Sample Sequencer Configuration
Configuration of the Sample Sequencers is slightly more complex than the module initialization since each sample sequence is completely programmable. The configuration for each Sample Sequencer should be as follows: 1. Ensure that the Sample Sequencer is disabled by writing a 0 to the corresponding ASEN bit in the ADCACTSS register. Programming of the Sample Sequencers is allowed without having them enabled. Disabling the Sequencer during programming prevents erroneous execution if a trigger event were to occur during the configuration process. 2. Configure the trigger event for the Sample Sequencer in the ADCEMUX register. 3. For each sample in the sample sequence, configure the corresponding input source in the ADCSSMUXn register. 4. For each sample in the sample sequence, configure the sample control bits in the corresponding nibble in the ADCSSCTLn register. When programming the last nibble, ensure that the END bit is set. Failure to set the END bit causes unpredictable behavior. 5. If interrupts are to be used, write a 1 to the corresponding MASK bit in the ADCIM register. 6. Enable the Sample Sequencer logic by writing a 1 to the corresponding ASEN bit in the ADCACTSS register.
11.4
Register Map
Table 11-2 lists the ADC registers. The offset listed is a hexadecimal increment to the register's address, relative to the ADC base address of 0x40038000.
Table 11-2.
Offset 0x000 0x004 0x008 0x00C 0x010 0x014 0x018
ADC Register Map
Name ADCACTSS ADCRIS ADCIM ADCISC ADCOSTAT ADCEMUX ADCUSTAT Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 Type R/W RO R/W R/W1C R/W1C R/W R/W1C Description Active sample sequencer Raw interrupt status and clear Interrupt mask Interrupt status and clear Overflow status Event multiplexer select Underflow status See page 213 214 215 216 217 218 219
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Analog-to-Digital Converter (ADC)
Table 11-2.
Offset 0x020 0x028 0x030 0x040 0x044 0x048 0x04C 0x060 0x064 0x068 0x06C 0x080 0x084 0x088 0x08C 0x0A0 0x0A4 0x0A8 0x0AC 0x100
ADC Register Map (Continued)
Name ADCSSPRI ADCPSSI ADCSAC ADCSSMUX0 ADCSSCTL0 ADCSSFIFO0 ADCSSFSTAT0 ADCSSMUX1 ADCSSCTL1 ADCSSFIFO1 ADCSSFSTAT1 ADCSSMUX2 ADCSSCTL2 ADCSSFIFO2 ADCSSFSTAT2 ADCSSMUX3 ADCSSCTL3 ADCSSFIFO3 ADCSSFSTAT3 ADCTMLB Reset 0x00003210 0x00000000 0x00000000 0x00000000 0x00000000 0x00000100 0x00000000 0x00000000 0x00000000 0x00000100 0x00000000 0x00000000 0x00000000 0x00000100 0x00000000 0x00000002 0x00000000 0x00000100 0x00000000 Type R/W WO R/W R/W R/W RO RO R/W R/W RO RO R/W R/W RO RO R/W R/W RO RO R/W Description Sample sequencer priority Processor sample sequence initiate Sample averaging control Sample sequence input multiplexer select 0 Sample sequence control 0 Sample sequence result FIFO 0 Sample sequence FIFO 0 status Sample sequence input multiplexer select 1 Sample sequence control 1 Sample sequence result FIFO 1 Sample sequence FIFO 1 status Sample sequence input multiplexer select 2 Sample sequence control 2 Sample sequence result FIFO 2 Sample sequence FIFO 2 status Sample sequence input multiplexer select 3 Sample sequence control 3 Sample sequence result FIFO 3 Sample sequence FIFO 3 status Test mode loopback See page 220 221 222 223 225 227 228 229 230 230 230 231 232 232 232 233 234 234 234 235
11.5
Register Descriptions
The remainder of this section lists and describes the ADC registers, in numerical order by address offset.
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LM3S317 Data Sheet
Register 1: ADC Active Sample Sequencer (ADCACTSS), offset 0x000 This register controls the activation of the Sample Sequencers. Each Sample Sequencer can be enabled/disabled independently.
ADC Active Sample Sequencer (ADCACTSS)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
ASEN3
R/W 0
ASEN2
R/W 0
ASEN1
R/W 0
ASEN0
R/W 0
Bit/Field 31:4 3
Name reserved ASEN3
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Specifies whether Sample Sequencer 3 is enabled. If set, the sample sequence logic for Sequencer 3 is active. Otherwise, the Sequencer is inactive. Specifies whether Sample Sequencer 2 is enabled. If set, the sample sequence logic for Sequencer 2 is active. Otherwise, the Sequencer is inactive. Specifies whether Sample Sequencer 1 is enabled. If set, the sample sequence logic for Sequencer 1 is active. Otherwise, the Sequencer is inactive. Specifies whether Sample Sequencer 0 is enabled. If set, the sample sequence logic for Sequencer 0 is active. Otherwise, the Sequencer is inactive.
2
ASEN2
R/W
0
1
ASEN1
R/W
0
0
ASEN0
R/W
0
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213
Analog-to-Digital Converter (ADC)
Register 2: ADC Raw Interrupt Status (ADCRIS), offset 0x004 This register shows the status of the raw interrupt signal of each Sample Sequencer. These bits may be polled by software to look for interrupt conditions without having to generate controller interrupts.
ADC Raw Interrupt Status (ADCRIS)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
INR3
RO 0
INR2
RO 0
INR1
RO 0
INR0
RO 0
Bit/Field 31:4 3
Name reserved INR3
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Set by hardware when a sample with its respective ADCSSCTL3 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN3 bit. Set by hardware when a sample with its respective ADCSSCTL2 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN2 bit. Set by hardware when a sample with its respective ADCSSCTL1 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN1 bit. Set by hardware when a sample with its respective ADCSSCTL0 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN0 bit.
2
INR2
RO
0
1
INR1
RO
0
0
INR0
RO
0
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LM3S317 Data Sheet
Register 3: ADC Interrupt Mask (ADCIM), offset 0x008 This register controls whether the Sample Sequencer raw interrupt signals are promoted to controller interrupts. The raw interrupt signal for each Sample Sequencer can be masked independently.
ADC Interrupt Mask (ADCIM)
Offset 0x008
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
MASK3 MASK2 MASK1 MASK0
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:4 3
Name reserved MASK3
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Specifies whether the raw interrupt signal from Sample Sequencer 3 (ADCRIS register INR3 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. Specifies whether the raw interrupt signal from Sample Sequencer 2 (ADCRIS register INR2 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. Specifies whether the raw interrupt signal from Sample Sequencer 1 (ADCRIS register INR1 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. Specifies whether the raw interrupt signal from Sample Sequencer 0 (ADCRIS register INR0 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not.
2
MASK2
R/W
0
1
MASK1
R/W
0
0
MASK0
R/W
0
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215
Analog-to-Digital Converter (ADC)
Register 4: ADC Interrupt Status and Clear (ADCISC), offset 0x00C This register provides the mechanism for clearing interrupt conditions, and shows the status of controller interrupts generated by the Sample Sequencers. When read, each bit field is the logical AND of the respective INR and MASK bits. Interrupts are cleared by writing a 1 to the corresponding bit position. If software is polling the ADCRIS instead of generating interrupts, the INR bits are still cleared via the ADCISC register, even if the IN bit is not set.
ADC Interrupt Status and Clear (ADCISC)
Offset 0x00C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IN3
R/W1C 0
IN2
R/W1C 0
IN1
R/W1C 0
IN0
R/W1C 0
Bit/Field 31:4 3
Name reserved IN3
Type RO R/W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit is set by hardware when the MASK3 and INR3 bits are both 1, providing a level-based interrupt to the controller. It is cleared by writing a 1, and also clears the INR3 bit. This bit is set by hardware when the MASK2 and INR2 bits are both 1, providing a level based interrupt to the controller. It is cleared by writing a 1, and also clears the INR2 bit. This bit is set by hardware when the MASK1 and INR1 bits are both 1, providing a level based interrupt to the controller. It is cleared by writing a 1, and also clears the INR1 bit. This bit is set by hardware when the MASK0 and INR0 bits are both 1, providing a level based interrupt to the controller. It is cleared by writing a 1, and also clears the INR0 bit.
2
IN2
R/W1C
0
1
IN1
R/W1C
0
0
IN0
R/W1C
0
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LM3S317 Data Sheet
Register 5: ADC Overflow Status (ADCOSTAT), offset 0x010 This register indicates overflow conditions in the Sample Sequencer FIFOs. Once the overflow condition has been handled by software, the condition can be cleared by writing a 1 to the corresponding bit position.
ADC Overflow Status (ADCOSTAT)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
OV3
R/W1C 0
OV2
R/W1C 0
OV1
R/W1C 0
OV0
R/W1C 0
Bit/Field 31:4 3
Name reserved OV3
Type RO R/W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit specifies that the FIFO for Sample Sequencer 3 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. This bit specifies that the FIFO for Sample Sequencer 2 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. This bit specifies that the FIFO for Sample Sequencer 1 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. This bit specifies that the FIFO for Sample Sequencer 0 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1.
2
OV2
R/W1C
0
1
OV1
R/W1C
0
0
OV0
R/W1C
0
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Analog-to-Digital Converter (ADC)
Register 6: ADC Event Multiplexer Select (ADCEMUX), offset 0x014 The ADCEMUX selects the event (trigger) that initiates sampling for each Sample Sequencer. Each Sample Sequencer can be configured with a unique trigger source.
ADC Event Multiplexer Select (ADCEMUX)
Offset 0x014
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
EM3
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
EM2
R/W 0 R/W 0 R/W 0 R/W 0
EM1
R/W 0 R/W 0 R/W 0 R/W 0
EM0
R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:12
Name reserved EM3
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This field selects the trigger source for Sample Sequencer 3. The valid configurations for this field are: EM Binary Value 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001-1110 1111 Event Controller (default) Analog Comparator 0 Reserved Reserved External (GPIO PB4) Timer PWM0 PWM1 PWM2 Reserved Always (continuously sample)
11:8 7:4 3:0
EM2 EM1 EM0
R/W R/W R/W
0 0 0
This field selects the trigger source for Sample Sequencer 2. The encodings are the same as those for EM3. This field selects the trigger source for Sample Sequencer 1. The encodings are the same as those for EM3. This field selects the trigger source for Sample Sequencer 0. The encodings are the same as those for EM3.
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LM3S317 Data Sheet
Register 7: ADC Underflow Status (ADCUSTAT), offset 0x018 This register indicates underflow conditions in the Sample Sequencer FIFOs. The corresponding underflow condition can be cleared by writing a 1 to the relevant bit position.
ADC Underflow Status (ADCUSTAT)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
UV3
R/W1C 0
UV2
R/W1C 0
UV1
R/W1C 0
UV0
R/W1C 0
Bit/Field 31:4 3
Name reserved UV3
Type RO R/W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. This bit specifies that the FIFO for Sample Sequencer 3 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. This bit specifies that the FIFO for Sample Sequencer 2 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. This bit specifies that the FIFO for Sample Sequencer 1 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. This bit specifies that the FIFO for Sample Sequencer 0 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1.
2
UV2
R/W1C
0
1
UV1
R/W1C
0
0
UV0
R/W1C
0
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219
Analog-to-Digital Converter (ADC)
Register 8: ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020 This register sets the priority for each of the Sample Sequencers. Out of reset, Sequencer 0 has the highest priority, and sample sequence 3 has the lowest priority. When reconfiguring sequence priorities, each sequence must have a unique priority or the ADC behavior is inconsistent.
ADC Sample Sequencer Priority (ADCSSPRI)
Offset 0x020
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 R/W 1
SS3
R/W 1
reserved
RO 0 RO 0 R/W 1
SS2
R/W 0
reserved
RO 0 RO 0 R/W 0
SS1
R/W 1
reserved
RO 0 RO 0 R/W 0
SS0
R/W 0
Bit/Field 31:14 13:12
Name reserved SS3
Type RO R/W
Reset 0 0x3
Description Reserved bits return an indeterminate value, and should never be changed. The SS3 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 3. A priority encoding of 0 is highest and 3 is lowest. The priorities assigned to the Sequencers must be uniquely mapped. ADC behavior is not consistent if two or more fields are equal. Reserved bits return an indeterminate value, and should never be changed. The SS2 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 2. Reserved bits return an indeterminate value, and should never be changed. The SS1 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 1. Reserved bits return an indeterminate value, and should never be changed. The SS0 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 0.
11:10 9:8 7:6 5:4 3:2 1:0
reserved SS2 reserved SS1 reserved SS0
RO R/W RO R/W RO R/W
0 0x2 0 0x1 0 0x0
220 Preliminary
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LM3S317 Data Sheet
Register 9: ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 This register provides a mechanism for application software to initiate sampling in the Sample Sequencers. Sample sequences can be initiated individually or in any combination. When multiple sequences are triggered simultaneously, the priority encodings in ADCSSPRI dictate execution order.
ADC Processor Sample Sequence Initiate (ADCPSSI)
Offset 0x028
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
WO 15 WO 14 WO 13 WO 12 WO 11 WO 10 WO 9 WO 8 WO 7 WO 6 WO 5 WO 4 WO 3 WO 2 WO 1 WO 0
reserved
Type Reset
WO WO WO WO WO WO WO WO WO WO WO WO -
SS3
WO -
SS2
WO -
SS1
WO -
SS0
WO -
Bit/Field 31:4 3
Name reserved SS3
Type WO WO
Reset -
Description Only a write by software is valid; a read of the register returns no meaningful data. Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 3, assuming the Sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 2, assuming the Sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 1, assuming the Sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 0, assuming the Sequencer is enabled in the ADCACTSS register.
2
SS2
WO
-
1
SS1
WO
-
0
SS0
WO
-
May 4, 2007 Preliminary
221
Analog-to-Digital Converter (ADC)
Register 10: ADC Sample Averaging Control (ADCSAC), offset 0x030 This register controls the amount of hardware averaging applied to conversion results. The final conversion result stored in the FIFO is averaged from 2AVG consecutive ADC samples at the specified ADC speed. If AVG is 0, the sample is passed directly through without any averaging. If AVG is 6, 64 consecutive ADC samples are averaged to generate one result in the sequencer FIFO. An AVG = 7 provides unpredictable results.
ADC Sample Averaging Control (ADCSAC)
Offset 0x030
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0
AVG
R/W 0 R/W 0
Bit/Field 31:3 2:0
Name reserved AVG
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Specifies the amount of hardware averaging that will be applied to ADC samples. The AVG field can be any value between 0 and 6. Entering a value of 7 creates unpredictable results.
222 Preliminary
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LM3S317 Data Sheet
Register 11: ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 0. This register is 32-bits wide and contains information for eight possible samples.
ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0)
Offset 0x040
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 R/W 0 14
MUX7
R/W 0 13 R/W 0 12
reserved
RO 0 11 R/W 0 10
MUX6
R/W 0 9 R/W 0 8
reserved
RO 0 7 R/W 0 6
MUX5
R/W 0 5 R/W 0 4
reserved
RO 0 3 R/W 0 2
MUX4
R/W 0 1 R/W 0 0
reserved
Type Reset
RO 0 R/W 0
MUX3
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX2
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX1
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX0
R/W 0 R/W 0
Bit/Field 31:30 29:28
Name reserved MUX7
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The MUX7 field is used during the eighth sample of a sequence executed with Sample Sequencer 0. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. The value set here indicates the corresponding pin, for example, a value of 1 indicates the input is ADC1. Reserved bits return an indeterminate value, and should never be changed. The MUX6 field is used during the seventh sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion. Reserved bits return an indeterminate value, and should never be changed. The MUX5 field is used during the sixth sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion. Reserved bits return an indeterminate value, and should never be changed. The MUX4 field is used during the fifth sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion. Reserved bits return an indeterminate value, and should never be changed. The MUX3 field is used during the fourth sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion.
27:26 25:24
reserved MUX6
RO R/W
0 0
23:22 21:20
reserved MUX5
RO R/W
0 0
19:18 17:16
reserved MUX4
RO R/W
0 0
15:14 13:12
reserved MUX3
RO R/W
0 0
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Analog-to-Digital Converter (ADC)
Bit/Field 11:10 9:8
Name reserved MUX2
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The MUX2 field is used during the third sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion. Reserved bits return an indeterminate value, and should never be changed. The MUX1 field is used during the second sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion. Reserved bits return an indeterminate value, and should never be changed. The MUX0 field is used during the first sample of a sequence executed with Sample Sequencer 0 and specifies which of the analog inputs is sampled for the analog-to-digital conversion.
7:6 5:4
reserved MUX1
RO R/W
0 0
3:2 1:0
reserved MUX0
RO R/W
0 0
224 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 12: ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 0. When configuring a sample sequence, the END bit must be set at some point, whether it be after the first sample, last sample, or any sample in between. This register is 32-bits wide and contains information for eight possible samples.
ADC Sample Sequence Control 0 (ADCSSCTL0)
Offset 0x044
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
TS7
Type Reset
R/W 0 15
IE7
R/W 0 14
END7
R/W 0 13
D7
R/W 0 12
TS6
R/W 0 11
IE6
R/W 0 10
END6
R/W 0 9
D6
R/W 0 8
TS5
R/W 0 7
IE5
R/W 0 6
END5
R/W 0 5
D5
R/W 0 4
TS4
R/W 0 3
IE4
R/W 0 2
END4
R/W 0 1
D4
R/W 0 0
TS3
Type Reset
R/W 0
IE3
R/W 0
END3
R/W 0
D3
R/W 0
TS2
R/W 0
IE2
R/W 0
END2
R/W 0
D2
R/W 0
TS1
R/W 0
IE1
R/W 0
END1
R/W 0
D1
R/W 0
TS0
R/W 0
IE0
R/W 0
END0
R/W 0
D0
R/W 0
Bit/Field 31
Name TS7
Type R/W
Reset 0
Description The TS7 bit is used during the eighth sample of the sample sequence and specifies the input source of the sample. If set, the temperature sensor is read. Otherwise, the input pin specified by the ADCSSMUX register is read. The IE7 bit is used during the eighth sample of the sample sequence and specifies whether the raw interrupt signal (INR0 bit) is asserted at the end of the sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to a controller-level interrupt. When this bit is set, the raw interrupt is asserted, otherwise it is not. It is legal to have multiple samples within a sequence generate interrupts. The END7 bit indicates that this is the last sample of the sequence. It is possible to end the sequence on any sample position. Samples defined after the sample containing a set END are not requested for conversion even though the fields may be non-zero. It is required that software write the END bit somewhere within the sequence. (Sample Sequencer 3, which only has a single sample in the sequence, is hardwired to have the END0 bit set.) Setting this bit indicates that this sample is the last in the sequence.
30
IE7
R/W
0
29
END7
R/W
0
28
D7
R/W
0
The D7 bit indicates that the analog input is to be differentially sampled. The corresponding ADCSSMUXx nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". The temperature sensor does not have a differential option. When set, the analog inputs are differentially sampled. Same definition as TS7 but used during the seventh sample. Same definition as IE7 but used during the seventh sample. Same definition as END7 but used during the seventh sample.
27 26 25
TS6 IE6 END6
R/W R/W R/W
0 0 0
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Analog-to-Digital Converter (ADC)
Bit/Field 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Name D6 TS5 IE5 END5 D5 TS4 IE4 END4 D4 TS3 IE3 END3 D3 TS2 IE2 END2 D2 TS1 IE1 END1 D1 TS0 IE0 END0
Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Description Same definition as D7 but used during the seventh sample. Same definition as TS7 but used during the sixth sample. Same definition as IE7 but used during the sixth sample. Same definition as END7 but used during the sixth sample. Same definition as D7 but used during the sixth sample. Same definition as TS7 but used during the fifth sample. Same definition as IE7 but used during the fifth sample. Same definition as END7 but used during the fifth sample. Same definition as D7 but used during the fifth sample. Same definition as TS7 but used during the fourth sample. Same definition as IE7 but used during the fourth sample. Same definition as END7 but used during the fourth sample. Same definition as D7 but used during the fourth sample. Same definition as TS7 but used during the third sample. Same definition as IE7 but used during the third sample. Same definition as END7 but used during the third sample. Same definition as D7 but used during the third sample. Same definition as TS7 but used during the second sample. Same definition as IE7 but used during the second sample. Same definition as END7 but used during the second sample. Same definition as D7 but used during the second sample. Same definition as TS7 but used during the first sample. Same definition as IE7 but used during the first sample. Same definition as END7 but used during the first sample. Since this sequencer has only one entry, this bit must be set.
0
D0
R/W
0
Same definition as D7 but used during the first sample.
226 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 13: ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048 This register contains the conversion results for samples collected with Sample Sequencer 0. Reads of this register return conversion result data in the order sample 0, sample 1, and so on, until the FIFO is empty. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers.
ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0)
Offset 0x048
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
DATA
RO 0 RO 0 RO 0 RO 0 RO 0
Bit/Field 31:10 9:0
Name reserved DATA
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Conversion result data.
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Register 14: ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C This register provides a window into the Sample Sequencer FIFO 0, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO.
ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0)
Offset 0x04C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0
FULL
RO 0 RO 0
reserved
RO 0 RO 0
EMPTY
RO 1 RO 0 RO 0
HPTR
RO 0 RO 0 RO 0 RO 0
TPTR
RO 0 RO 0
Bit/Field 31:13 12 11:9 8 7:4 3:0
Name reserved FULL reserved EMPTY HPTR TPTR
Type RO RO RO RO RO RO
Reset 0 0 0 1 0 0
Description Reserved bits return an indeterminate value, and should never be changed. When set, indicates that the FIFO is currently full. Reserved bits return an indeterminate value, and should never be changed. When set, indicates that the FIFO is currently empty. This field contains the current "head" pointer index for the FIFO, that is, the next entry to be written. This field contains the current "tail" pointer index for the FIFO, that is, the next entry to be read.
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Register 15: ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 1. This register is 16-bits wide and contains information for four possible samples. This register's bit fields are as shown in the diagram below. Bit field definitions are the same as those in the ADCSSMUX0 register (see page 223) but are for Sample Sequencer 1.
ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1)
Offset 0x060
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 R/W 0
MUX3
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX2
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX1
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX0
R/W 0 R/W 0
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Register 16: ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 1. When configuring a sample sequence, the END bit must be set at some point, whether it be after the first sample, last sample, or any sample in between. This register is 16-bits wide and contains information for four possible samples. This register's bit fields are as shown in the diagram below. Bit field definitions are the same as those in the ADCSSCTL0 register (see page 225) but are for Sample Sequencer 1.
ADC Sample Sequence Control 1 (ADCSSCTL1)
Offset 0x064
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
TS3
Type Reset
R/W 0
IE3
R/W 0
END3
R/W 0
D3
R/W 0
TS2
R/W 0
IE2
R/W 0
END2
R/W 0
D2
R/W 0
TS1
R/W 0
IE1
R/W 0
END1
R/W 0
D1
R/W 0
TS0
R/W 0
IE0
R/W 0
END0
R/W 0
D0
R/W 0
Register 17: ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068 This register contains the conversion results for samples collected with Sample Sequencer 1. Reads of this register return conversion result data in the order sample 0, sample 1, and so on, until the FIFO is empty. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers. Bit fields and definitions are the same as ADCSSFIFO0 (see page 227) but are for FIFO 1. Register 18: ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C This register provides a window into the Sample Sequencer FIFO 1, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO. This register has the same bit fields and definitions as ADCSSFSTAT0 (see page 228) but is for FIFO 1.
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Register 19: ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 2. This register is 16-bits wide and contains information for four possible samples. This register's bit fields are as shown in the diagram below. Bit field definitions are the same as those in the ADCSSMUX0 register (see page 223) but are for Sample Sequencer 2.
ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2)
Offset 0x080
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 R/W 0
MUX3
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX2
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX1
R/W 0 R/W 0
reserved
RO 0 R/W 0
MUX0
R/W 0 R/W 0
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Analog-to-Digital Converter (ADC)
Register 20: ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 2. When configuring a sample sequence, the END bit must be set at some point, whether it be after the first sample, last sample, or any sample in between. This register is 16-bits wide and contains information for four possible samples. This register's bit fields are as shown in the diagram below. Bit field definitions are the same as those in the ADCSSCTL0 register (see page 225) but are for Sample Sequencer 2.
ADC Sample Sequence Control 2 (ADCSSCTL2)
Offset 0x084
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
TS3
Type Reset
R/W 0
IE3
R/W 0
END3
R/W 0
D3
R/W 0
TS2
R/W 0
IE2
R/W 0
END2
R/W 0
D2
R/W 0
TS1
R/W 0
IE1
R/W 0
END1
R/W 0
D1
R/W 0
TS0
R/W 0
IE0
R/W 0
END0
R/W 0
D0
R/W 0
Register 21: ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088 This register contains the conversion results for samples collected with Sample Sequencer 2. Reads of this register return conversion result data in the order sample 0, sample 1, and so on, until the FIFO is empty. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers. Bit fields and definitions are the same as ADCSSFIFO0 (see page 227) but are for FIFO 2. Register 22: ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C This register provides a window into the Sample Sequencer FIFO 2, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO. This register has the same bit fields and definitions as ADCSSFSTAT0 (see page 228) but is for FIFO 2.
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Register 23: ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 3. This register is 4-bits wide and contains information for one possible sample. This register's bit fields are as shown in the diagram below. Bit field definitions are the same as those in the ADCSSMUX0 register ( see page 223) but are for Sample Sequencer 3.
ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3)
Offset 0x0A0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0
MUX0
R/W 0 R/W 0
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Register 24: ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 3. The END bit is always set since there is only one sample in this sequencer. This register is 4-bits wide and contains information for one possible sample. This register's bit fields are as shown in the diagram below. Bit field definitions are the same as those in the ADCSSCTL0 register (see page 225) but are for Sample Sequencer 3.
ADC Sample Sequence Control 3 (ADCSSCTL3)
Offset 0x0A4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TS0
R/W 0
IE0
R/W 0
END0
R/W 1
D0
R/W 0
Register 25: ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 This register contains the conversion results for samples collected with Sample Sequencer 3. Reads of this register return the conversion result data. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers. Bit fields and definitions are the same as ADCSSFIFO0 (see page 227) but are for FIFO 3. Register 26: ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC This register provides a window into the Sample Sequencer FIFO 3, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO. This register has the same bit fields and definitions as ADCSSFSTAT0 (see page 228) but is for FIFO 3.
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Register 27: ADC Test Mode Loopback (ADCTMLB), offset 0x100 This register provides loopback operation within the digital logic of the ADC, which can be useful in debugging software without having to provide actual analog stimulus. This test mode is entered by writing a value of 0x00000001 to this register. When data is read from the FIFO in loopback mode, the read-only portion of this register is returned.
ADC Test Mode Loopback (ADCTMLB): Read
Offset 0x100
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CNT
RO 0 RO 0
CONT
RO 0
DIFF
RO 0
TS
RO 0 RO 0
MUX
RO 0 RO 0
ADC Test Mode Loopback (ADCTMLB):Write
Offset 0x100
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
LB
WO 0
Bit/Field
Name
Type
Reset
Description
Read-Only Register 31:10 9:6 reserved CNT RO RO 0 0 Reserved bits return an indeterminate value, and should never be changed. Continuous sample counter that is initialized to 0 and counts each sample as it processed. This helps provide a unique value for the data received. When set, indicates that this is a continuation sample. For example if two sequencers were to run back-to-back, this indicates that the controller kept continuously sampling at full rate. When set, indicates that this was to be a differential sample. When set, indicates that this was to be a temperature sensor sample. Indicate which analog input was to be sampled.
5
CONT
RO
0
4 3 2:0
DIFF TS MUX
RO RO RO
0 0 0
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Bit/Field
Name
Type
Reset
Description
Write-Only Register 31:1 0 reserved LB RO WO 0 0 Reserved bits return an indeterminate value, and should never be changed. When set, forces a loopback within the digital block to provide information on input and unique numbering. The 10-bit loopback data is defined as shown in the read for bits 9:0 below.
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LM3S317 Data Sheet
12
Universal Asynchronous Receiver/Transmitter (UART)
The Universal Asynchronous Receiver/Transmitter (UART) provides fully programmable, 16C550-type serial interface characteristics. The LM3S317 controller is equipped with one UART module. The UART has the following features: Separate transmit and receive FIFOs Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8 Programmable baud-rate generator allowing rates up to 460.8 Kbps Standard asynchronous communication bits for start, stop and parity False start bit detection Line-break generation and detection Fully programmable serial interface characteristics: - 5, 6, 7, or 8 data bits - Even, odd, stick, or no-parity bit generation/detection - 1 or 2 stop bit generation
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12.1
Block Diagram
Figure 12-1. UART Module Block Diagram
System Clock
Interrupt
Interrupt Control UARTIFLS UARTIM UARTMIS
TXFIFO 16x8
. . .
Transmitter Baud Rate Generator UARTIBRD UARTFBRD Receiver UnRx UnTx
Identification Registers UARTPCellID0 UARTPCellID1 UARTPCellID2 UARTPCellID3 UARTPeriphID0 UARTPeriphID1 UARTPeriphID2 UARTPeriphID3 UART PeriphID4 UARTPeriphID5 UARTPeriphID6 UARTPeriphID7
UARTRIS UARTICR
UARTDR
Control / Status UARTRSR/ECR UARTFR UARTLCRH UARTCTL
RXFIFO 16x8
. . .
12.2
Functional Description
The Stellaris UART performs the functions of parallel-to-serial and serial-to-parallel conversions. It is similar in functionality to a 16C550 UART, but is not register compatible. The UART is configured for transmit and/or receive via the TXE and RXE bits of the UART Control (UARTCTL) register (see page 254). Transmit and receive are both enabled out of reset. Before any control registers are programmed, the UART must be disabled by clearing the UARTEN bit in UARTCTL. If the UART is disabled during a TX or RX operation, the current transaction is completed prior to the UART stopping.
12.2.1
Transmit/Receive Logic
The transmit logic performs parallel-to-serial conversion on the data read from the transmit FIFO. The control logic outputs the serial bit stream beginning with a start bit, and followed by the data
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bits (LSB first), parity bit, and the stop bits according to the programmed configuration in the control registers. See Figure 12-2 for details. The receive logic performs serial-to-parallel conversion on the received bit stream after a valid start pulse has been detected. Overrun, parity, frame error checking, and line-break detection are also performed, and their status accompanies the data that is written to the receive FIFO. Figure 12-2. UART Character Frame
UnTX 1 0 n Start LSB 5-8 data bits Parity bit if enabled MSB
1-2 stop bits
12.2.2
Baud-Rate Generation
The baud-rate divisor is a 22-bit number consisting of a 16-bit integer and a 6-bit fractional part. The number formed by these two values is used by the baud-rate generator to determine the bit period. Having a fractional baud-rate divider allows the UART to generate all the standard baud rates. The 16-bit integer is loaded through the UART Integer Baud-Rate Divisor (UARTIBRD) register (see page 250) and the 6-bit fractional part is loaded with the UART Fractional Baud-Rate Divisor (UARTFBRD) register (see page 251). The baud-rate divisor (BRD) has the following relationship to the system clock (where BRDI is the integer part of the BRD and BRDF is the fractional part, separated by a decimal place.):
BRD = BRDI + BRDF = SysClk / (16 * Baud Rate)
The 6-bit fractional number (that is to be loaded into the DIVFRAC bit field in the UARTFBRD register) can be calculated by taking the fractional part of the baud-rate divisor, multiplying it by 64, and adding 0.5 to account for rounding errors:
UARTFBRD[DIVFRAC] = integer(BRDF * 64 + 0.5)
The UART generates an internal baud-rate reference clock at 16x the baud-rate (referred to as Baud16). This reference clock is divided by 16 to generate the transmit clock, and is used for error detection during receive operations. Along with the UART Line Control, High Byte (UARTLCRH) register (see page 252), the UARTIBRD and UARTFBRD registers form an internal 30-bit register. This internal register is only updated when a write operation to UARTLCRH is performed, so any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register for the changes to take effect. To update the baud-rate registers, there are four possible sequences: UARTIBRD write, UARTFBRD write, and UARTLCRH write UARTFBRD write, UARTIBRD write, and UARTLCRH write UARTIBRD write and UARTLCRH write UARTFBRD write and UARTLCRH write
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12.2.3
Data Transmission
Data received or transmitted is stored in two 16-byte FIFOs, though the receive FIFO has an extra four bits per character for status information. For transmission, data is written into the transmit FIFO. If the UART is enabled, it causes a data frame to start transmitting with the parameters indicated in the UARTLCRH register. Data continues to be transmitted until there is no data left in the transmit FIFO. The BUSY bit in the UART Flag (UARTFR) register (see page 248) is asserted as soon as data is written to the transmit FIFO (that is, if the FIFO is non-empty) and remains asserted while data is being transmitted. The BUSY bit is negated only when the transmit FIFO is empty, and the last character has been transmitted from the shift register, including the stop bits. The UART can indicate that it is busy even though the UART may no longer be enabled. When the receiver is idle (U0Rx is continuously 1) and the data input goes Low (a start bit has been received), the receive counter begins running and data is sampled on the eighth cycle of Baud16 (described in "Transmit/Receive Logic" on page 238). The start bit is valid if U0Rx is still low on the eighth cycle of Baud16, otherwise a false start bit is detected and it is ignored. Start bit errors can be viewed in the UART Receive Status (UARTRSR) register (see page 246). If the start bit was valid, successive data bits are sampled on every 16th cycle of Baud16 (that is, one bit period later) according to the programmed length of the data characters. The parity bit is then checked if parity mode was enabled. Data length and parity are defined in the UARTLCRH register. Lastly, a valid stop bit is confirmed if U0Rx is High, otherwise a framing error has occurred. When a full word is received, the data is stored in the receive FIFO, with any error bits associated with that word.
12.2.4
FIFO Operation
The UART has two 16-entry FIFOs; one for transmit and one for receive. Both FIFOs are accessed via the UART Data (UARTDR) register (see page 244). Read operations of the UARTDR register return a 12-bit value consisting of 8 data bits and 4 error flags while write operations place 8-bit data in the transmit FIFO. Out of reset, both FIFOs are disabled and act as 1-byte-deep holding registers. The FIFOs are enabled by setting the FEN bit in UARTLCRH (page 252). FIFO status can be monitored via the UART Flag (UARTFR) register (see page 248) and the UART Receive Status (UARTRSR) register. Hardware monitors empty, full and overrun conditions. The UARTFR register contains empty and full flags (TXFE, TXFF, RXFE and RXFF bits) and the UARTRSR register shows overrun status via the OE bit. The trigger points at which the FIFOs generate interrupts is controlled via the UART Interrupt FIFO Level Select (UARTIFLS) register (see page 255). Both FIFOs can be individually configured to trigger interrupts at different levels. Available configurations include 1/8, 1/4, 1/2, 3/4 and 7/8. For example, if the 1/4 option is selected for the receive FIFO, the UART generates a receive interrupt after 4 data bytes are received. Out of reset, both FIFOs are configured to trigger an interrupt at the 1/2 mark.
12.2.5
Interrupts
The UART can generate interrupts when the following conditions are observed: Overrun Error Break Error Parity Error Framing Error
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Receive Timeout Transmit (when condition defined in the TXIFLSEL bit in the UARTIFLS register is met) Receive (when condition defined in the RXIFLSEL bit in the UARTIFLS register is met) All of the interrupt events are ORed together before being sent to the interrupt controller, so the UART can only generate a single interrupt request to the controller at any given time. Software can service multiple interrupt events in a single interrupt service routine by reading the UART Masked Interrupt Status (UARTMIS) register (see page 259). The interrupt events that can trigger a controller-level interrupt are defined in the UART Interrupt Mask (UARTIM) register (see page 256) by setting the corresponding IM bit to 1. If interrupts are not used, the raw interrupt status is always visible via the UART Raw Interrupt Status (UARTRIS) register (see page 258). Interrupts are always cleared (for both the UARTMIS and UARTRIS registers) by setting the corresponding bit in the UART Interrupt Clear (UARTICR) register (see page 260).
12.2.6
Loopback Operation
The UART can be placed into an internal loopback mode for diagnostic or debug work. This is accomplished by setting the LBE bit in the UARTCTL register (see page 254). In loopback mode, data transmitted on the U0Tx output is received on the U0Rx input.
12.3
Initialization and Configuration
To use the UART, the peripheral clock must be enabled by setting the UART0 bit in the RCGC1 register. This section discusses the steps that are required for using a UART module. For this example, the system clock is assumed to be 20 MHz and the desired UART configuration is: 115200 baud rate Data length of 8 bits One stop bit No parity FIFOs disabled No interrupts The first thing to consider when programming the UART is the baud-rate divisor (BRD), since the UARTIBRD and UARTFBRD registers must be written before the UARTLCRH register. Using the equation described in "Baud-Rate Generation" on page 239, the BRD can be calculated:
BRD = 20,000,000 / (16 * 115,200) = 10.8507
which means that the DIVINT field of the UARTIBRD register (see page 250) should be set to 10. The value to be loaded into the UARTFBRD register (see page 251) is calculated by the equation:
UARTFBRD[DIVFRAC] = integer(0.8507 * 64 + 0.5) = 54
With the BRD values in hand, the UART configuration is written to the module in the following order: 1. Disable the UART by clearing the UARTEN bit in the UARTCTL register. 2. Write the integer portion of the BRD to the UARTIBRD register.
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Universal Asynchronous Receiver/Transmitter (UART)
3. Write the fractional portion of the BRD to the UARTFBRD register. 4. Write the desired serial parameters to the UARTLCRH register (in this case, a value of 0x00000060). 5. Enable the UART by setting the UARTEN bit in the UARTCTL register.
12.4
Register Map
Table 12-1 lists the UART registers. The offset listed is a hexadecimal increment to the register's address, relative to that UART's base address: UART0: 0x4000C000 Note: The UART must be disabled (see the UARTEN bit in the UARTCTL register on page 254) before any of the control registers are reprogrammed. When the UART is disabled during a TX or RX operation, the current transaction is completed prior to the UART stopping.
Table 12-1.
Offset 0x000 0x004
UART Register Map
Name UARTDR UARTRSR UARTECR Reset 0x00000000 0x00000000 Type R/W R/W Description Data Receive Status (read) Error Clear (write) 0x00000090 0x00000000 0x00000000 0x00000000 0x00000300 0x00000012 0x00000000 0x0000000F 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000011 0x00000000 0x00000018 0x00000001 RO R/W R/W R/W R/W R/W R/W RO RO W1C RO RO RO RO RO RO RO RO Flag Register (read only) Integer Baud-Rate Divisor Fractional Baud-Rate Divisor Line Control Register, High byte Control Register Interrupt FIFO Level Select Interrupt Mask Raw Interrupt Status Masked Interrupt Status Interrupt Clear Peripheral identification 4 Peripheral identification 5 Peripheral identification 6 Peripheral identification 7 Peripheral identification 0 Peripheral identification 1 Peripheral identification 2 Peripheral identification 3 248 250 251 252 254 255 256 258 259 260 261 262 263 264 265 266 267 268 See page 244 246
0x018 0x024 0x028 0x02C 0x030 0x034 0x038 0x03C 0x040 0x044 0xFD0 0xFD4 0xFD8 0xFDC 0xFE0 0xFE4 0xFE8 0xFEC
UARTFR UARTIBRD UARTFBRD UARTLCRH UARTCTL UARTIFLS UARTIM UARTRIS UARTMIS UARTICR UARTPeriphID4 UARTPeriphID5 UARTPeriphID6 UARTPeriphID7 UARTPeriphID0 UARTPeriphID1 UARTPeriphID2 UARTPeriphID3
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Table 12-1.
Offset 0xFF0 0xFF4 0xFF8 0xFFC
UART Register Map (Continued)
Name UARTPCellID0 UARTPCellID1 UARTPCellID2 UARTPCellID3 Reset 0x0000000D 0x000000F0 0x00000005 0x000000B1 Type RO RO RO RO Description PrimeCell identification 0 PrimeCell identification 1 PrimeCell identification 2 PrimeCell identification 3 See page 269 270 271 272
12.5
Register Descriptions
The remainder of this section lists and describes the UART registers, in numerical order by address offset.
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Register 1: UART Data (UARTDR), offset 0x000 This register is the data register (the interface to the FIFOs). When FIFOs are enabled, data written to this location is pushed onto the transmit FIFO. If FIFOs are disabled, data is stored in the transmitter holding register (the bottom word of the transmit FIFO). A write to this register initiates a transmission from the UART. For received data, if the FIFO is enabled, the data byte and the 4-bit status (break, frame, parity and overrun) is pushed onto the 12-bit wide receive FIFO. If FIFOs are disabled, the data byte and status are stored in the receiving holding register (the bottom word of the receive FIFO). The received data can be retrieved by reading this register.
UART Data (UARTDR)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0
OE
RO 0
BE
RO 0
PE
RO 0
FE
RO 0 R/W 0 R/W 0 R/W 0
DATA
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:12 11
Name reserved OE
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. UART Overrun Error 1=New data was received when the FIFO was full, resulting in data loss. 0=There has been no data loss due to a FIFO overrun.
10
BE
RO
0
UART Break Error This bit is set to 1 when a break condition is detected, indicating that the receive data input was held Low for longer than a fullword transmission time (defined as start, data, parity, and stop bits). In FIFO mode, this error is associated with the character at the top of the FIFO. When a break occurs, only one 0 character is loaded into the FIFO. The next character is only enabled after the received data input goes to a 1 (marking state) and the next valid start bit is received.
9
PE
RO
0
UART Parity Error This bit is set to 1 when the parity of the received data character does not match the parity defined by bits 2 and 7 of the UARTLCRH register. In FIFO mode, this error is associated with the character at the top of the FIFO.
244 Preliminary
May 4, 2007
LM3S317 Data Sheet
Bit/Field 8
Name FE
Type RO
Reset 0
Description UART Framing Error This bit is set to 1 when the received character does not have a valid stop bit (a valid stop bit is 1).
7:0
DATA
R/W
0
When written, the data that is to be transmitted via the UART. When read, the data that was received by the UART.
May 4, 2007 Preliminary
245
Universal Asynchronous Receiver/Transmitter (UART)
Register 2: UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 The UARTRSR/UARTECR register is the receive status register/error clear register. In addition to the UARTDR register, receive status can also be read from the UARTRSR register. If the status is read from this register, then the status information corresponds to the entry read from UARTDR prior to reading UARTRSR. The status information for overrun is set immediately when an overrun condition occurs. A write of any value to the UARTECR register clears the framing, parity, break, and overrun errors. All the bits are cleared to 0 on reset.
UART Receive Status (UARTRSR): Read
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
OE
RO 0
BE
RO 0
PE
RO 0
FE
RO 0
UART Error Clear (UARTECR): Write
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
WO 0 15 WO 0 14 WO 0 13 WO 0 12 WO 0 11 WO 0 10 WO 0 9 WO 0 8 WO 0 7 WO 0 6 WO 0 5 WO 0 4 WO 0 3 WO 0 2 WO 0 1 WO 0 0
reserved
Type Reset
WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0
DATA
WO 0 WO 0 WO 0 WO 0
Bit/Field
Name
Type
Reset
Description
Read-Only Receive Status (UARTRSR) Register 31:4 3 reserved OE RO RO 0 0 Reserved bits return an indeterminate value, and should never be changed. The UARTRSR register cannot be written. UART Overrun Error When this bit is set to 1, data is received and the FIFO is already full. This bit is cleared to 0 by a write to UARTECR. The FIFO contents remain valid since no further data is written when the FIFO is full, only the contents of the shift register are overwritten. The CPU must now read the data in order to empty the FIFO.
246 Preliminary
May 4, 2007
LM3S317 Data Sheet
Bit/Field 2
Name BE
Type RO
Reset 0
Description UART Break Error This bit is set to 1 when a break condition is detected, indicating that the received data input was held Low for longer than a fullword transmission time (defined as start, data, parity, and stop bits). This bit is cleared to 0 by a write to UARTECR. In FIFO mode, this error is associated with the character at the top of the FIFO. When a break occurs, only one 0 character is loaded into the FIFO. The next character is only enabled after the receive data input goes to a 1 (marking state) and the next valid start bit is received.
1
PE
RO
0
UART Parity Error This bit is set to 1 when the parity of the received data character does not match the parity defined by bits 2 and 7 of the UARTLCRH register. This bit is cleared to 0 by a write to UARTECR.
0
FE
RO
0
UART Framing Error This bit is set to 1 when the received character does not have a valid stop bit (a valid stop bit is 1). This bit is cleared to 0 by a write to UARTECR. In FIFO mode, this error is associated with the character at the top of the FIFO.
Write-Only Error Clear (UARTECR) Register 31:8 7:0 reserved DATA WO WO 0 0 Reserved bits return an indeterminate value, and should never be changed. A write to this register of any data clears the framing, parity, break and overrun flags.
May 4, 2007 Preliminary
247
Universal Asynchronous Receiver/Transmitter (UART)
Register 3: UART Flag (UARTFR), offset 0x018 The UARTFR register is the flag register. After reset, the TXFF, RXFF, and BUSY bits are 0, and TXFE and RXFE bits are 1.
UART Flag (UARTFR)
Offset 0x018
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TXFE
RO 1
RXFF
RO 0
TXFF
RO 0
RXFE
RO 1
BUSY
RO 0 RO 0
reserved
RO 0 RO 0
Bit/Field 31:8 7
Name reserved TXFE
Type RO RO
Reset 0 1
Description Reserved bits return an indeterminate value, and should never be changed. UART Transmit FIFO Empty The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled (FEN is 0), this bit is set when the transmit holding register is empty. If the FIFO is enabled (FEN is 1), this bit is set when the transmit FIFO is empty.
6
RXFF
RO
0
UART Receive FIFO Full The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled, this bit is set when the receive holding register is full. If the FIFO is enabled, this bit is set when the receive FIFO is full.
5
TXFF
RO
0
UART Transmit FIFO Full The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled, this bit is set when the transmit holding register is full. If the FIFO is enabled, this bit is set when the transmit FIFO is full.
248 Preliminary
May 4, 2007
LM3S317 Data Sheet
Bit/Field 4
Name RXFE
Type RO
Reset 1
Description UART Receive FIFO Empty The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled, this bit is set when the receive holding register is empty. If the FIFO is enabled, this bit is set when the receive FIFO is empty.
3
BUSY
RO
0
UART Busy When this bit is 1, the UART is busy transmitting data. This bit remains set until the complete byte, including all stop bits, has been sent from the shift register. This bit is set as soon as the transmit FIFO becomes non-empty (regardless of whether UART is enabled).
2:0
reserved
RO
0
Reserved bits return an indeterminate value, and should never be changed.
May 4, 2007 Preliminary
249
Universal Asynchronous Receiver/Transmitter (UART)
Register 4: UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 The UARTIBRD register is the integer part of the baud-rate divisor value. All the bits are cleared on reset. The minimum possible divide ratio is 1 (when UARTIBRD=0), in which case the UARTFBRD register is ignored. When changing the UARTIBRD register, the new value does not take effect until transmission/reception of the current character is complete. Any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register. See "Baud-Rate Generation" on page 239 for configuration details.
UART Integer Baud-Rate Divisor
Offset 0x024
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
DIVINT
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:0
Name reserved DIVINT
Type RO R/W
Reset 0 0x0000
Description Reserved bits return an indeterminate value, and should never be changed. Integer Baud-Rate Divisor
250 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 5: UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 The UARTFBRD register is the fractional part of the baud-rate divisor value. All the bits are cleared on reset. When changing the UARTFBRD register, the new value does not take effect until transmission/reception of the current character is complete. Any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register. See "Baud-Rate Generation" on page 239 for configuration details.
UART Fractional Baud-Rate Divisor (UARTFBRD)
Offset 0x028
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0
DIVFRAC
R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:6 5:0
Name reserved DIVFRAC
Type RO R/W
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. Fractional Baud-Rate Divisor
May 4, 2007 Preliminary
251
Universal Asynchronous Receiver/Transmitter (UART)
Register 6: UART Line Control (UARTLCRH), offset 0x02C The UARTLCRH register is the line control register. Serial parameters such as data length, parity and stop bit selection are implemented in this register. When updating the baud-rate divisor (UARTIBRD and/or UARTIFRD), the UARTLCRH register must also be written. The write strobe for the baud-rate divisor registers is tied to the UARTLCRH register.
UART Line Control (UARTLCRH)
Offset 0x02C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
SPS
R/W 0
WLEN
R/W 0 R/W 0
FEN
R/W 0
STP2
R/W 0
EPS
R/W 0
PEN
R/W 0
BRK
R/W 0
Bit/Field 31:8 7
Name reserved SPS
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. UART Stick Parity Select When bits 1, 2 and 7 of UARTLCRH are set, the parity bit is transmitted and checked as a 0. When bits 1 and 7 are set and 2 is cleared, the parity bit is transmitted and checked as a 1. When this bit is cleared, stick parity is disabled.
6:5
WLEN
R/W
0
UART Word Length The bits indicate the number of data bits transmitted or received in a frame as follows: 0x3: 8 bits 0x2: 7 bits 0x1: 6 bits 0x0: 5 bits (default)
4
FEN
R/W
0
UART Enable FIFOs If this bit is set to 1, transmit and receive FIFO buffers are enabled (FIFO mode). When cleared to 0, FIFOs are disabled (Character mode). The FIFOs become 1-byte-deep holding registers.
3
STP2
R/W
0
UART Two Stop Bits Select If this bit is set to 1, two stop bits are transmitted at the end of a frame. The receive logic does not check for two stop bits being received.
252 Preliminary
May 4, 2007
LM3S317 Data Sheet
Bit/Field 2
Name EPS
Type R/W
Reset 0
Description UART Even Parity Select If this bit is set to 1, even parity generation and checking is performed during transmission and reception, which checks for an even number of 1s in data and parity bits. When cleared to 0, then odd parity is performed, which checks for an odd number of 1s. This bit has no effect when parity is disabled by the PEN bit.
1
PEN
R/W
0
UART Parity Enable If this bit is set to 1, parity checking and generation is enabled; otherwise, parity is disabled and no parity bit is added to the data frame.
0
BRK
R/W
0
UART Send Break If this bit is set to 1, a Low level is continually output on the UNTX output, after completing transmission of the current character. For the proper execution of the break command, the software must set this bit for at least two frames (character periods). For normal use, this bit must be cleared to 0.
May 4, 2007 Preliminary
253
Universal Asynchronous Receiver/Transmitter (UART)
Register 7: UART Control (UARTCTL), offset 0x030 The UARTCTL register is the control register. All the bits are cleared on reset except for the Transmit Enable (TXE) and Receive Enable (RXE) bits, which are set to 1. To enable the UART module, the UARTEN bit must be set to 1. If software requires a configuration change in the module, the UARTEN bit must be cleared before the configuration changes are written. If the UART is disabled during a transmit or receive operation, the current transaction is completed prior to the UART stopping.
UART Control (UARTCR)
Offset 0x030
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
RXE
R/W 1
TXE
R/W 1
LBE
R/W 0 RO 0 RO 0 RO 0
reserved
RO 0 RO 0 RO 0
UARTEN
R/W 0
Bit/Field 31:10 9
Name reserved RXE
Type RO R/W
Reset 0 1
Description Reserved bits return an indeterminate value, and should never be changed. UART Receive Enable If this bit is set to 1, the receive section of the UART is enabled. When the UART is disabled in the middle of a receive, it completes the current character before stopping.
8
TXE
R/W
1
UART Transmit Enable If this bit is set to 1, the transmit section of the UART is enabled. When the UART is disabled in the middle of a transmission, it completes the current character before stopping.
7
LBE
R/W
0
UART Loop Back Enable If this bit is set to 1, the UNTX path is fed through the UNRX path.
6:1 0
reserved UARTEN
RO R/W
0 0
Reserved bits return an indeterminate value, and should never be changed. UART Enable If this bit is set to 1, the UART is enabled. When the UART is disabled in the middle of transmission or reception, it completes the current character before stopping.
254 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 8: UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 The UARTIFLS register is the interrupt FIFO level select register. You can use this register to define the FIFO level at which the TXRIS and RXRIS bits in the UARTRIS register are triggered. The interrupts are generated based on a transition through a level rather than being based on the level. That is, the interrupts are generated when the fill level progresses through the trigger level. For example, if the receive trigger level is set to the half-way mark, the interrupt is triggered as the module is receiving the 9th character. Out of reset, the TXIFLSEL and RXIFLSEL bits are configured so that the FIFOs trigger an interrupt at the half-way mark.
UART Interrupt FIFO Level Select (UARTIFLS)
Offset 0x034
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0
RXIFLSEL
R/W 1 R/W 0 R/W 0
TXIFLSEL
R/W 1 R/W 0
Bit/Field 31:6 5:3
Name reserved RXIFLSEL
Type RO R/W
Reset 0 0X2
Description Reserved bits return an indeterminate value, and should never be changed. UART Receive Interrupt FIFO Level Select The trigger points for the receive interrupt are as follows: 000: RX FIFO 1/8 full 001: RX FIFO 1/4 full 010: RX FIFO 1/2 full (default) 011: RX FIFO 3/4 full 100: RX FIFO 7/8 full 101-111: Reserved
2:0
TXIFLSEL
R/W
0X2
UART Transmit Interrupt FIFO Level Select The trigger points for the transmit interrupt are as follows: 000: TX FIFO 1/8 full 001: TX FIFO 1/4 full 010: TX FIFO 1/2 full (default) 011: TX FIFO 3/4 full 100: TX FIFO 7/8 full 101-111: Reserved
May 4, 2007 Preliminary
255
Universal Asynchronous Receiver/Transmitter (UART)
Register 9: UART Interrupt Mask (UARTIM), offset 0x038 The UARTIM register is the interrupt mask set/clear register. On a read, this register gives the current value of the mask on the relevant interrupt. Writing a 1 to a bit allows the corresponding raw interrupt signal to be routed to the interrupt controller. Writing a 0 prevents the raw interrupt signal from being sent to the interrupt controller.
UART Interrupt Mask (UARTIM)
Offset 0x038
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
OEIM
R/W 0
BEIM
R/W 0
PEIM
R/W 0
FEIM
R/W 0
RTIM
R/W 0
TXIM
R/W 0
RXIM
R/W 0 RO 0
reserved
RO 0 RO 0 RO 0
Bit/Field 31:11 10
Name reserved OEIM
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. UART Overrun Error Interrupt Mask On a read, the current mask for the OEIM interrupt is returned. Setting this bit to 1 promotes the OEIM interrupt to the interrupt controller.
9
BEIM
R/W
0
UART Break Error Interrupt Mask On a read, the current mask for the BEIM interrupt is returned. Setting this bit to 1 promotes the BEIM interrupt to the interrupt controller.
8
PEIM
R/W
0
UART Parity Error Interrupt Mask On a read, the current mask for the PEIM interrupt is returned. Setting this bit to 1 promotes the PEIM interrupt to the interrupt controller.
7
FEIM
R/W
0
UART Framing Error Interrupt Mask On a read, the current mask for the FEIM interrupt is returned. Setting this bit to 1 promotes the FEIM interrupt to the interrupt controller.
6
RTIM
R/W
0
UART Receive Time-Out Interrupt Mask On a read, the current mask for the RTIM interrupt is returned. Setting this bit to 1 promotes the RTIM interrupt to the interrupt controller.
256 Preliminary
May 4, 2007
LM3S317 Data Sheet
Bit/Field 5
Name TXIM
Type R/W
Reset 0
Description UART Transmit Interrupt Mask On a read, the current mask for the TXIM interrupt is returned. Setting this bit to 1 promotes the TXIM interrupt to the interrupt controller.
4
RXIM
R/W
0
UART Receive Interrupt Mask On a read, the current mask for the RXIM interrupt is returned. Setting this bit to 1 promotes the RXIM interrupt to the interrupt controller.
3:0
reserved
RO
0
Reserved bits return an indeterminate value, and should never be changed.
May 4, 2007 Preliminary
257
Universal Asynchronous Receiver/Transmitter (UART)
Register 10: UART Raw Interrupt Status (UARTRIS), offset 0x03C The UARTRIS register is the raw interrupt status register. On a read, this register gives the current raw status value of the corresponding interrupt. A write has no effect.
UART Raw Interrupt Status (UARTRIS)
Offset 0x03C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
OERIS
RO 0
BERIS
RO 0
PERIS
RO 0
FERIS
RO 0
RTRIS
RO 0
TXRIS
RO 0
RXRIS
RO 0 RO 1 RO 1
reserved
RO 1 RO 1
Bit/Field 31:11 10
Name reserved OERIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. UART Overrun Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
9
BERIS
RO
0
UART Break Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
8
PERIS
RO
0
UART Parity Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
7
FERIS
RO
0
UART Framing Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
6
RTRIS
RO
0
UART Receive Time-Out Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
5
TXRIS
RO
0
UART Transmit Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
4
RXRIS
RO
0
UART Receive Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt.
3:0
reserved
RO
0xF
This reserved bit is read-only and has a reset value of 0xF.
258 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 11: UART Masked Interrupt Status (UARTMIS), offset 0x040 The UARTMIS register is the masked interrupt status register. On a read, this register gives the current masked status value of the corresponding interrupt. A write has no effect.
UART Masked Interrupt Status (UARTMIS)
Offset 0x040
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
OEMIS
RO 0
BEMIS
RO 0
PEMIS
RO 0
FEMIS
RO 0
RTMIS
RO 0
TXMIS RXMIS
RO 0 RO 0 RO 0 RO 0
reserved
RO 0 RO 0
Bit/Field 31:11 10
Name reserved OEMIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. UART Overrun Error Masked Interrupt Status Gives the masked interrupt state of this interrupt.
9
BEMIS
RO
0
UART Break Error Masked Interrupt Status Gives the masked interrupt state of this interrupt.
8
PEMIS
RO
0
UART Parity Error Masked Interrupt Status Gives the masked interrupt state of this interrupt.
7
FEMIS
RO
0
UART Framing Error Masked Interrupt Status Gives the masked interrupt state of this interrupt.
6
RTMIS
RO
0
UART Receive Time-Out Masked Interrupt Status Gives the masked interrupt state of this interrupt.
5
TXMIS
RO
0
UART Transmit Masked Interrupt Status Gives the masked interrupt state of this interrupt.
4
RXMIS
RO
0
UART Receive Masked Interrupt Status Gives the masked interrupt state of this interrupt.
3:0
reserved
RO
0
Reserved bits return an indeterminate value, and should never be changed.
May 4, 2007 Preliminary
259
Universal Asynchronous Receiver/Transmitter (UART)
Register 12: UART Interrupt Clear (UARTICR), offset 0x044 The UARTICR register is the interrupt clear register. On a write of 1, the corresponding interrupt (both raw interrupt and masked interrupt, if enabled) is cleared. A write of 0 has no effect.
UART Interrupt Clear (UARTICR)
Offset 0x044
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0
OEIC
W1C 0
BEIC
W1C 0
PEIC
W1C 0
FEIC
W1C 0
RTIC
W1C 0
TXIC
W1C 0
RXIC
W1C 0 RO 0 RO 0
reserved
RO 0 RO 0
Bit/Field 31:11 10
Name reserved OEIC
Type RO W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Overrun Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
9
BEIC
W1C
0
Break Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
8
PEIC
W1C
0
Parity Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
7
FEIC
W1C
0
Framing Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
6
RTIC
W1C
0
Receive Time-Out Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
5
TXIC
W1C
0
Transmit Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
4
RXIC
W1C
0
Receive Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt.
3:0
reserved
RO
0
Reserved bits return an indeterminate value, and should never be changed.
260 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 13: UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 4 (UARTPeriphID4)
Offset 0xFD0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID4
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID4
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[7:0]
May 4, 2007 Preliminary
261
Universal Asynchronous Receiver/Transmitter (UART)
Register 14: UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 5 (UARTPeriphID5)
Offset 0xFD4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID5
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID5
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[15:8]
262 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 15: UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 6 (UARTPeriphID6)
Offset 0xFD8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID6
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID6
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[23:16]
May 4, 2007 Preliminary
263
Universal Asynchronous Receiver/Transmitter (UART)
Register 16: UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 7 (UARTPeriphID7)
Offset 0xFDC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID7
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID7
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[31:24]
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LM3S317 Data Sheet
Register 17: UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 0 (UARTPeriphID0)
Offset 0xFE0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1
PID0
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID0
Type RO RO
Reset 0 0x11
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral.
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Universal Asynchronous Receiver/Transmitter (UART)
Register 18: UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 1 (UARTPeriphID1)
Offset 0xFE4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID1
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[15:8] Can be used by software to identify the presence of this peripheral.
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LM3S317 Data Sheet
Register 19: UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 2 (UARTPeriphID2)
Offset 0xFE8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1
PID2
RO 1 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID2
Type RO RO
Reset 0 0x18
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[23:16] Can be used by software to identify the presence of this peripheral.
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Universal Asynchronous Receiver/Transmitter (UART)
Register 20: UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Peripheral Identification 3 (UARTPeriphID3)
Offset 0xFEC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID3
Type RO RO
Reset 0 0x01
Description Reserved bits return an indeterminate value, and should never be changed. UART Peripheral ID Register[31:24] Can be used by software to identify the presence of this peripheral.
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LM3S317 Data Sheet
Register 21: UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Primecell Identification 0 (UARTPCellID0)
Offset 0xFF0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID0
RO 1 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID0
Type RO RO
Reset 0 0x0D
Description Reserved bits return an indeterminate value, and should never be changed. UART PrimeCell ID Register[7:0] Provides software a standard cross-peripheral identification system.
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Universal Asynchronous Receiver/Transmitter (UART)
Register 22: UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Primecell Identification 1 (UARTPCellID1)
Offset 0xFF4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 1
CID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved CID1
Type RO RO
Reset 0 0xF0
Description Reserved bits return an indeterminate value, and should never be changed. UART PrimeCell ID Register[15:8] Provides software a standard cross-peripheral identification system.
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LM3S317 Data Sheet
Register 23: UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Primecell Identification 2 (UARTPCellID2)
Offset 0xFF8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID2
RO 0 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID2
Type RO RO
Reset 0 0x05
Description Reserved bits return an indeterminate value, and should never be changed. UART PrimeCell ID Register[23:16] Provides software a standard cross-peripheral identification system.
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Universal Asynchronous Receiver/Transmitter (UART)
Register 24: UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values.
UART Primecell Identification 3 (UARTPCellID3)
Offset 0xFFC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 RO 1
CID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID3
Type RO RO
Reset 0 0xB1
Description Reserved bits return an indeterminate value, and should never be changed. UART PrimeCell ID Register[31:24] Provides software a standard cross-peripheral identification system.
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LM3S317 Data Sheet
13
Synchronous Serial Interface (SSI)
The Stellaris Synchronous Serial Interface (SSI) is a master or slave interface for synchronous serial communication with peripheral devices that have either Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces. The Stellaris SSI has the following features: Master or slave operation Programmable clock bit rate and prescale Separate transmit and receive FIFOs, 16 bits wide, 8 locations deep Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces Programmable data frame size from 4 to 16 bits Internal loopback test mode for diagnostic/debug testing
13.1
Block Diagram
Figure 13-1. SSI Module Block Diagram
Interrupt Interrupt Control SSIIM SSIMIS Control / Status SSICR0 SSICR1 SSISR SSIDR RxFIFO 8 x 16 System Clock Clock Prescaler Identification Registers SSIPCellID0 SSIPCellID1 SSIPCellID2 SSIPCellID3 SSIPeriphID 0 SSIPeriphID 1 SSIPeriphID 2 SSIPeriphID 3 SSIPeriphID 4 SSIPeriphID 5 SSIPeriphID 6 SSIPeriphID 7 SSICPSR Transmit / Receive Logic SSIRIS SSIICR TxFIFO 8 x 16
. . .
SSITx SSIRx SSIClk SSIFss
. . .
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13.2
Functional Description
The SSI performs serial-to-parallel conversion on data received from a peripheral device. The CPU accesses data, control, and status information. The transmit and receive paths are buffered with internal FIFO memories allowing up to eight 16-bit values to be stored independently in both transmit and receive modes.
13.2.1
Bit Rate Generation
The SSI includes a programmable bit rate clock divider and prescaler to generate the serial output clock. Bit rates are supported to 2 MHz and higher, although maximum bit rate is determined by peripheral devices. The serial bit rate is derived by dividing down the 25-MHz input clock. The clock is first divided by an even prescale value CPSDVSR from 2 to 254, which is programmed in the SSI Clock Prescale (SSICPSR) register (see page 291). The clock is further divided by a value from 1 to 256, which is 1 + SCR, where SCR is the value programmed in the SSI Control0 (SSICR0) register (see page 285). The frequency of the output clock SSICLK is defined by:
FSSIClk = FSysClk / (CPSDVSR * (1 + SCR))
Note that although the SSICLK transmit clock can theoretically be 12.5 MHz, the module may not be able to operate at that speed. For master mode, the system clock must be at least two times faster than the SSICLK. For slave mode, the system clock must be at least 12 times faster than the SSICLK. See "Electrical Characteristics" on page 360 to view SSI timing parameters.
13.2.2
13.2.2.1
FIFO Operation
Transmit FIFO The common transmit FIFO is a 16-bit wide, 8-locations deep, first-in, first-out memory buffer. The CPU writes data to the FIFO by writing the SSI Data (SSIDR) register (see page 289), and data is stored in the FIFO until it is read out by the transmission logic. When configured as a master or a slave, parallel data is written into the transmit FIFO prior to serial conversion and transmission to the attached slave or master, respectively, through the SSITX pin.
13.2.2.2
Receive FIFO The common receive FIFO is a 16-bit wide, 8-locations deep, first-in, first-out memory buffer. Received data from the serial interface is stored in the buffer until read out by the CPU, which accesses the read FIFO by reading the SSIDR register. When configured as a master or slave, serial data received through the SSIRX pin is registered prior to parallel loading into the attached slave or master receive FIFO, respectively.
13.2.3
Interrupts
The SSI can generate interrupts when the following conditions are observed: Transmit FIFO service Receive FIFO service Receive FIFO time-out Receive FIFO overrun
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LM3S317 Data Sheet
All of the interrupt events are ORed together before being sent to the interrupt controller, so the SSI can only generate a single interrupt request to the controller at any given time. You can mask each of the four individual maskable interrupts by setting the appropriate bits in the SSI Interrupt Mask (SSIIM) register (see page 292). Setting the appropriate mask bit to 1 enables the interrupt. Provision of the individual outputs, as well as a combined interrupt output, allows use of either a global interrupt service routine, or modular device drivers to handle interrupts. The transmit and receive dynamic dataflow interrupts have been separated from the status interrupts so that data can be read or written in response to the FIFO trigger levels. The status of the individual interrupt sources can be read from the SSI Raw Interrupt Status (SSIRIS) and SSI Masked Interrupt Status (SSIMIS) registers (see page 293 and page 294, respectively).
13.2.4
Frame Formats
Each data frame is between 4 and 16 bits long, depending on the size of data programmed, and is transmitted starting with the MSB. There are three basic frame types that can be selected: Texas Instruments synchronous serial Freescale SPI MICROWIRE For all three formats, the serial clock (SSICLK) is held inactive while the SSI is idle, and SSICLK transitions at the programmed frequency only during active transmission or reception of data. The idle state of SSICLK is utilized to provide a receive timeout indication that occurs when the receive FIFO still contains data after a timeout period. For Freescale SPI and MICROWIRE frame formats, the serial frame (SSIFSS) pin is active Low, and is asserted (pulled down) during the entire transmission of the frame. For Texas Instruments synchronous serial frame format, the SSIFSS pin is pulsed for one serial clock period starting at its rising edge, prior to the transmission of each frame. For this frame format, both the SSI and the off-chip slave device drive their output data on the rising edge of SSICLK, and latch data from the other device on the falling edge. Unlike the full-duplex transmission of the other two frame formats, the MICROWIRE format uses a special master-slave messaging technique, which operates at half-duplex. In this mode, when a frame begins, an 8-bit control message is transmitted to the off-chip slave. During this transmit, no incoming data is received by the SSI. After the message has been sent, the off-chip slave decodes it and, after waiting one serial clock after the last bit of the 8-bit control message has been sent, responds with the requested data. The returned data can be 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits.
13.2.4.1
Texas Instruments Synchronous Serial Frame Format Figure 13-2 shows the Texas Instruments synchronous serial frame format for a single transmitted frame. Figure 13-2. TI Synchronous Serial Frame Format (Single Transfer)
SSIClk SSIFss SSITx/SSIRx MSB 4 to 16 bits LSB
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Synchronous Serial Interface (SSI)
In this mode, SSICLK and SSIFSS are forced Low, and the transmit data line SSITX is tristated whenever the SSI is idle. Once the bottom entry of the transmit FIFO contains data, SSIFSS is pulsed High for one SSICLK period. The value to be transmitted is also transferred from the transmit FIFO to the serial shift register of the transmit logic. On the next rising edge of SSICLK, the MSB of the 4 to 16-bit data frame is shifted out on the SSITX pin. Likewise, the MSB of the received data is shifted onto the SSIRX pin by the off-chip serial slave device. Both the SSI and the off-chip serial slave device then clock each data bit into their serial shifter on the falling edge of each SSICLK. The received data is transferred from the serial shifter to the receive FIFO on the first rising edge of SSICLK after the LSB has been latched. Figure 13-3 shows the Texas Instruments synchronous serial frame format when back-to-back frames are transmitted. Figure 13-3. TI Synchronous Serial Frame Format (Continuous Transfer)
SSIClk SSIFss SSITx/SSIRx
MSB 4 to 16 bits LSB
13.2.4.2
Freescale SPI Frame Format The Freescale SPI interface is a four-wire interface where the SSIFSS signal behaves as a slave select. The main feature of the Freescale SPI format is that the inactive state and phase of the SSICLK signal are programmable through the SPO and SPH bits within the SSISCR0 control register. SPO Clock Polarity Bit When the SPO clock polarity control bit is Low, it produces a steady state Low value on the SSICLK pin. If the SPO bit is High, a steady state High value is placed on the SSICLK pin when data is not being transferred. SPH Phase Control Bit The SPH phase control bit selects the clock edge that captures data and allows it to change state. It has the most impact on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge. When the SPH phase control bit is Low, data is captured on the first clock edge transition. If the SPH bit is High, data is captured on the second clock edge transition.
13.2.4.3
Freescale SPI Frame Format with SPO=0 and SPH=0 Single and continuous transmission signal sequences for Freescale SPI format with SPO=0 and SPH=0 are shown in Figure 13-4 and Figure 13-5.
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LM3S317 Data Sheet
Figure 13-4. Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0
SSIClk SSIFss SSIRx MSB 4 to 16 bits SSITx MSB LSB LSB Q
Figure 13-5. Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0
SSIClk SSIFss SSIRx LSB MSB 4 to 16 bits SSITx LSB MSB LSB MSB LSB MSB
In this configuration, during idle periods: SSICLK is forced Low SSIFSS is forced High The transmit data line SSITX is arbitrarily forced Low When the SSI is configured as a master, it enables the SSICLK pad When the SSI is configured as a slave, it disables the SSICLK pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFSS master signal being driven Low. This causes slave data to be enabled onto the SSIRX input line of the master. The master SSITX output pad is enabled. One half SSICLK period later, valid master data is transferred to the SSITX pin. Now that both the master and slave data have been set, the SSICLK master clock pin goes High after one further half SSICLK period. The data is now captured on the rising and propagated on the falling edges of the SSICLK signal. In the case of a single word transmission, after all bits of the data word have been transferred, the SSIFSS line is returned to its idle High state one SSICLK period after the last bit has been captured. However, in the case of continuous back-to-back transmissions, the SSIFSS signal must be pulsed High between each data word transfer. This is because the slave select pin freezes the data in its serial peripheral register and does not allow it to be altered if the SPH bit is logic zero. Therefore, the master device must raise the SSIFSS pin of the slave device between each data transfer to enable the serial peripheral data write. On completion of the continuous transfer, the SSIFSS pin is returned to its idle state one SSICLK period after the last bit has been captured. 13.2.4.4 Freescale SPI Frame Format with SPO=0 and SPH=1 The transfer signal sequence for Freescale SPI format with SPO=0 and SPH=1 is shown in Figure 13-6, which covers both single and continuous transfers.
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Synchronous Serial Interface (SSI)
Figure 13-6. Freescale SPI Frame Format with SPO=0 and SPH=1
SSIClk SSIFss SSIRx Q MSB 4 to 16 bits SSITx MSB LSB LSB Q
In this configuration, during idle periods: SSICLK is forced Low SSIFSS is forced High The transmit data line SSITX is arbitrarily forced Low When the SSI is configured as a master, it enables the SSICLK pad When the SSI is configured as a slave, it disables the SSICLK pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFSS master signal being driven Low. The master SSITX output is enabled. After a further one half SSICLK period, both master and slave valid data is enabled onto their respective transmission lines. At the same time, the SSICLK is enabled with a rising edge transition. Data is then captured on the falling edges and propagated on the rising edges of the SSICLK signal. In the case of a single word transfer, after all bits have been transferred, the SSIFSS line is returned to its idle High state one SSICLK period after the last bit has been captured. For continuous back-to-back transfers, the SSIFSS pin is held Low between successive data words and termination is the same as that of the single word transfer. 13.2.4.5 Freescale SPI Frame Format with SPO=1 and SPH=0 Single and continuous transmission signal sequences for Freescale SPI format with SPO=1 and SPH=0 are shown in Figure 13-7 and Figure 13-8. Figure 13-7. Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0
SSIClk SSIFss SSIRx MSB 4 to 16 bits SSITx MSB LSB LSB Q
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LM3S317 Data Sheet
Figure 13-8. Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0
SSIClk SSIFss SSITx/SSIRx LSB MSB 4 to 16 bits LSB MSB
In this configuration, during idle periods: SSICLK is forced High SSIFSS is forced High The transmit data line SSITX is arbitrarily forced Low When the SSI is configured as a master, it enables the SSICLK pad When the SSI is configured as a slave, it disables the SSICLK pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFSS master signal being driven Low, which causes slave data to be immediately transferred onto the SSIRX line of the master. The master SSITX output pad is enabled. One half period later, valid master data is transferred to the SSITX line. Now that both the master and slave data have been set, the SSICLK master clock pin becomes Low after one further half SSICLK period. This means that data is captured on the falling edges and propagated on the rising edges of the SSICLK signal. In the case of a single word transmission, after all bits of the data word are transferred, the SSIFSS line is returned to its idle High state one SSICLK period after the last bit has been captured. However, in the case of continuous back-to-back transmissions, the SSIFSS signal must be pulsed High between each data word transfer. This is because the slave select pin freezes the data in its serial peripheral register and does not allow it to be altered if the SPH bit is logic zero. Therefore, the master device must raise the SSIFSS pin of the slave device between each data transfer to enable the serial peripheral data write. On completion of the continuous transfer, the SSIFSS pin is returned to its idle state one SSICLK period after the last bit has been captured. 13.2.4.6 Freescale SPI Frame Format with SPO=1 and SPH=1 The transfer signal sequence for Freescale SPI format with SPO=1 and SPH=1 is shown in Figure 13-9, which covers both single and continuous transfers. Figure 13-9. Freescale SPI Frame Format with SPO=1 and SPH=1
SSIClk SSIFss SSIRx Q MSB 4 to 16 bits SSITx MSB LSB LSB Q
Note:
Q is undefined in Figure 13-9.
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Synchronous Serial Interface (SSI)
In this configuration, during idle periods: SSICLK is forced High SSIFSS is forced High The transmit data line SSITX is arbitrarily forced Low When the SSI is configured as a master, it enables the SSICLK pad When the SSI is configured as a slave, it disables the SSICLK pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFSS master signal being driven Low. The master SSITX output pad is enabled. After a further one-half SSICLK period, both master and slave data are enabled onto their respective transmission lines. At the same time, SSICLK is enabled with a falling edge transition. Data is then captured on the rising edges and propagated on the falling edges of the SSICLK signal. After all bits have been transferred, in the case of a single word transmission, the SSIFSS line is returned to its idle high state one SSICLK period after the last bit has been captured. For continuous back-to-back transmissions, the SSIFSS pin remains in its active Low state, until the final bit of the last word has been captured, and then returns to its idle state as described above. For continuous back-to-back transfers, the SSIFSS pin is held Low between successive data words and termination is the same as that of the single word transfer. 13.2.4.7 MICROWIRE Frame Format Figure 13-10 shows the MICROWIRE frame format, again for a single frame. Figure 13-11 shows the same format when back-to-back frames are transmitted. Figure 13-10.
SSIClk SSIFss SSITx SSIRx
MSB LSB
MICROWIRE Frame Format (Single Frame)
8-bit control 0
MSB LSB
4 to 16 bits output data
MICROWIRE format is very similar to SPI format, except that transmission is half-duplex instead of full-duplex, using a master-slave message passing technique. Each serial transmission begins with an 8-bit control word that is transmitted from the SSI to the off-chip slave device. During this transmission, no incoming data is received by the SSI. After the message has been sent, the off-chip slave decodes it and, after waiting one serial clock after the last bit of the 8-bit control message has been sent, responds with the required data. The returned data is 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits. In this configuration, during idle periods: SSICLK is forced Low SSIFSS is forced High The transmit data line SSITX is arbitrarily forced Low
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LM3S317 Data Sheet
A transmission is triggered by writing a control byte to the transmit FIFO. The falling edge of SSIFSS causes the value contained in the bottom entry of the transmit FIFO to be transferred to the serial shift register of the transmit logic, and the MSB of the 8-bit control frame to be shifted out onto the SSITX pin. SSIFSS remains Low for the duration of the frame transmission. The SSIRX pin remains tristated during this transmission. The off-chip serial slave device latches each control bit into its serial shifter on the rising edge of each SSICLK. After the last bit is latched by the slave device, the control byte is decoded during a one clock wait-state, and the slave responds by transmitting data back to the SSI. Each bit is driven onto the SSIRX line on the falling edge of SSICLK. The SSI in turn latches each bit on the rising edge of SSICLK. At the end of the frame, for single transfers, the SSIFSS signal is pulled High one clock period after the last bit has been latched in the receive serial shifter, which causes the data to be transferred to the receive FIFO. Note: The off-chip slave device can tristate the receive line either on the falling edge of SSICLK after the LSB has been latched by the receive shifter, or when the SSIFSS pin goes High.
For continuous transfers, data transmission begins and ends in the same manner as a single transfer. However, the SSIFSS line is continuously asserted (held Low) and transmission of data occurs back-to-back. The control byte of the next frame follows directly after the LSB of the received data from the current frame. Each of the received values is transferred from the receive shifter on the falling edge of SSICLK, after the LSB of the frame has been latched into the SSI. Figure 13-11.
SSIClk SSIFss SSITx
LSB MSB LSB
MICROWIRE Frame Format (Continuous Transfer)
8-bit control SSIRx 0
MSB LSB MSB
4 to 16 bits output data
In the MICROWIRE mode, the SSI slave samples the first bit of receive data on the rising edge of SSICLK after SSIFSS has gone Low. Masters that drive a free-running SSICLK must ensure that the SSIFSS signal has sufficient setup and hold margins with respect to the rising edge of SSICLK. Figure 13-12 illustrates these setup and hold time requirements. With respect to the SSICLK rising edge on which the first bit of receive data is to be sampled by the SSI slave, SSIFSS must have a setup of at least two times the period of SSICLK on which the SSI operates. With respect to the SSICLK rising edge previous to this edge, SSIFSS must have a hold of at least one SSICLK period.
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Synchronous Serial Interface (SSI)
Figure 13-12.
MICROWIRE Frame Format, SSIFss Input Setup and Hold Requirements
tSetup =(2*tSSIClk ) tHold=tSSIClk SSIClk SSIFss SSIRx
First RX data to be sampled by SSI slave
13.3
Initialization and Configuration
To use the SSI, its peripheral clock must be enabled by setting the SSI bit in the RCGC1 register. For each of the frame formats, the SSI is configured using the following steps: 1. Ensure that the SSE bit in the SSICR1 register is disabled before making any configuration changes. 2. Select whether the SSI is a master or slave: a. For master operations, set the SSICR1 register to 0x00000000. b. For slave mode (output enabled), set the SSICR1 register to 0x00000004. c. For slave mode (output disabled), set the SSICR1 register to 0x0000000C. 3. Configure the clock prescale divisor by writing the SSICPSR register. 4. Write the SSICR0 register with the following configuration: - Serial clock rate (SCR) - Desired clock phase/polarity, if using Freescale SPI mode (SPH and SPO) - The protocol mode: Freescale SPI, TI SSF, MICROWIRE (FRF) - The data size (DSS) 5. Enable the SSI by setting the SSE bit in the SSICR1 register. As an example, assume the SSI must be configured to operate with the following parameters: Master operation Freescale SPI mode (SPO=1, SPH=1) 1 Mbps bit rate 8 data bits Assuming the system clock is 20 MHz, the bit rate calculation would be:
FSSIClk = FSysClk / (CPSDVSR * (1 + SCR)) ' 1x106 = 20x106 / (CPSDVSR * (1 + SCR))
In this case, if CPSDVSR=2, SCR must be 9. The configuration sequence would be as follows: 1. Ensure that the SSE bit in the SSICR1 register is disabled. 2. Write the SSICR1 register with a value of 0x00000000.
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LM3S317 Data Sheet
3. Write the SSICPSR register with a value of 0x00000002. 4. Write the SSICR0 register with a value of 0x000009C7. 5. The SSI is then enabled by setting the SSE bit in the SSICR1 register to 1.
13.4
Register Map
Table 13-1 lists the SSI registers. The offset listed is a hexadecimal increment to the register's address, relative to the SSI base address of 0x40008000. Note: The SSI must be disabled (see the SSE bit in the SSICR1 register) before any of the control registers are reprogrammed.
Table 13-1.
Offset 0x000 0x004 0x008 0x00C 0x010 0x014 0x018 0x01C 0x020 0xFD0 0xFD4 0xFD8 0xFDC 0xFE0 0xFE4 0xFE8 0xFEC 0xFF0 0xFF4 0xFF8 0xFFC
SSI Register Map
Name SSICR0 SSICR1 SSIDR SSISR SSICPSR SSIIM SSIRIS SSIMIS SSIICR SSIPeriphID4 SSIPeriphID5 SSIPeriphID6 SSIPeriphID7 SSIPeriphID0 SSIPeriphID1 SSIPeriphID2 SSIPeriphID3 SSIPCellID0 SSIPCellID1 SSIPCellID2 SSIPCellID3 Reset 0x00000000 0x00000000 0x00000000 0x00000003 0x00000000 0x00000000 0x00000008 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000022 0x00000000 0x00000018 0x00000001 0x0000000D 0x000000F0 0x00000005 0x000000B1 Type R/W R/W R/W RO R/W R/W RO RO W1C RO RO RO RO RO RO RO RO RO RO RO RO Description Control 0 Control 1 Data Status Clock prescale Interrupt mask Raw interrupt status Masked interrupt status Interrupt clear Peripheral identification 4 Peripheral identification 5 Peripheral identification 6 Peripheral identification 7 Peripheral identification 0 Peripheral identification 1 Peripheral identification 2 Peripheral identification 3 PrimeCell identification 0 PrimeCell identification 1 PrimeCell identification 2 PrimeCell identification 3 See page 285 287 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307
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13.5
Register Descriptions
The remainder of this section lists and describes the SSI registers, in numerical order by address offset.
284 Preliminary
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LM3S317 Data Sheet
Register 1: SSI Control 0 (SSICR0), offset 0x000 SSICR0 is control register 0 and contains bit fields that control various functions within the SSI module. Functionality such as protocol mode, clock rate and data size are configured in this register.
SSI Control 0 (SSICR0)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
SCR
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
SPH
R/W 0
SPO
R/W 0 R/W 0
FRF
R/W 0 R/W 0 R/W 0
DSS
R/W 0 R/W 0
Bit/Field 31:16 15:8
Name reserved SCR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Serial Clock Rate The value SCR is used to generate the transmit and receive bit rate of the SSI. The bit rate is: BR= FSSICLK/(CPSDVSR * (1 + SCR)) where CPSDVSR is an even value from 2-254 programmed in the SSICPSR register, and SCR is a value from 0-255.
7
SPH
R/W
0
SSI Serial Clock Phase This bit is only applicable to the Freescale SPI Format. The SPH control bit selects the clock edge that captures data and allows it to change state. It has the most impact on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge. When the SPH bit is 0, data is captured on the first clock edge transition. If SPH is 1, data is captured on the second clock edge transition.
6
SPO
R/W
0
SSI Serial Clock Polarity This bit is only applicable to the Freescale SPI Format. When the SPO bit is 0, it produces a steady state Low value on the SSICLK pin. If SPO is 1, a steady state High value is placed on the SSICLK pin when data is not being transferred.
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Synchronous Serial Interface (SSI)
Bit/Field 5:4
Name FRF
Type R/W
Reset 0
Description SSI Frame Format Select. The FRF values are defined as follows: FRF Value 00 01 10 11 Frame Format Freescale SPI Frame Format Texas Instruments Synchronous Serial Frame Format MICROWIRE Frame Format Reserved
3:0
DSS
R/W
0
SSI Data Size Select The DSS values are defined as follows: DSS Value 0000-0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Data Size Reserved 4-bit data 5-bit data 6-bit data 7-bit data 8-bit data 9-bit data 10-bit data 11-bit data 12-bit data 13-bit data 14-bit data 15-bit data 16-bit data
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LM3S317 Data Sheet
Register 2: SSI Control 1 (SSICR1), offset 0x004 SSICR1 is control register 1 and contains bit fields that control various functions within the SSI module. Master and slave mode functionality is controlled by this register.
SSI Control 1 (SSCR1)
Offset 0x004
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
SOD
R/W 0
MS
R/W 0
SSE
R/W 0
LBM
R/W 0
Bit/Field 31:4 3
Name reserved SOD
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Slave Mode Output Disable This bit is relevant only in the Slave mode (MS=1). In multiple-slave systems, it is possible for the SSI master to broadcast a message to all slaves in the system while ensuring that only one slave drives data onto the serial output line. In such systems, the TXD lines from multiple slaves could be tied together. To operate in such a system, the SOD bit can be configured so that the SSI slave does not drive the SSITX pin. 0: SSI can drive SSITX output in Slave Output mode. 1: SSI must not drive the SSITX output in Slave mode.
2
MS
R/W
0
SSI Master/Slave Select This bit selects Master or Slave mode and can be modified only when SSI is disabled (SSE=0). 0: Device configured as a master. 1: Device configured as a slave.
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Synchronous Serial Interface (SSI)
Bit/Field 1
Name SSE
Type R/W
Reset 0
Description SSI Synchronous Serial Port Enable Setting this bit enables SSI operation. 0: SSI operation disabled. 1: SSI operation enabled. Note: This bit must be set to 0 before any control registers are reprogrammed.
0
LBM
R/W
0
SSI Loopback Mode Setting this bit enables Loopback Test mode. 0: Normal serial port operation enabled. 1: Output of the transmit serial shift register is connected internally to the input of the receive serial shift register.
288 Preliminary
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LM3S317 Data Sheet
Register 3: SSI Data (SSIDR), offset 0x008 SSIDR is the data register and is 16-bits wide. When SSIDR is read, the entry in the receive FIFO (pointed to by the current FIFO read pointer) is accessed. As data values are removed by the SSI receive logic from the incoming data frame, they are placed into the entry in the receive FIFO (pointed to by the current FIFO write pointer). When SSIDR is written to, the entry in the transmit FIFO (pointed to by the write pointer) is written to. Data values are removed from the transmit FIFO one value at a time by the transmit logic. It is loaded into the transmit serial shifter, then serially shifted out onto the SSITx pin at the programmed bit rate. When a data size of less than 16 bits is selected, the user must right-justify data written to the transmit FIFO. The transmit logic ignores the unused bits. Received data less than 16 bits is automatically right-justified in the receive buffer. When the SSI is programmed for MICROWIRE frame format, the default size for transmit data is eight bits (the most significant byte is ignored). The receive data size is controlled by the programmer. The transmit FIFO and the receive FIFO are not cleared even when the SSE bit in the SSICR1 register is set to zero. This allows the software to fill the transmit FIFO before enabling the SSI.
SSI Data (SSIDR)
Offset 0x008
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
DATA
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:0
Name reserved DATA
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Receive/Transmit Data A read operation reads the receive FIFO. A write operation writes the transmit FIFO. Software must right-justify data when the SSI is programmed for a data size that is less than 16 bits. Unused bits at the top are ignored by the transmit logic. The receive logic automatically right-justifies the data.
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Synchronous Serial Interface (SSI)
Register 4: SSI Status (SSISR), offset 0x00C SSISR is a status register that contains bits that indicate the FIFO fill status and the SSI busy status.
SSI Status (SSISR)
Offset 0x00C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
BSY
RO 0
RFF
RO 0
RNE
RO 0
TNF
RO 1
TFE
RO 1
Bit/Field 31:5 4
Name reserved BSY
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Busy Bit 0: SSI is idle. 1: SSI is currently transmitting and/or receiving a frame, or the transmit FIFO is not empty.
3
RFF
RO
0
SSI Receive FIFO Full 0: Receive FIFO is not full. 1: Receive FIFO is full.
2
RNE
RO
0
SSI Receive FIFO Not Empty 0: Receive FIFO is empty. 1: Receive FIFO is not empty.
1
TNF
RO
1
SSI Transmit FIFO Not Full 0: Transmit FIFO is full. 1: Transmit FIFO is not full.
0
TFE
R0
1
SSI Transmit FIFO Empty 0: Transmit FIFO is not empty. 1: Transmit FIFO is empty.
290 Preliminary
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LM3S317 Data Sheet
Register 5: SSI Clock Prescale (SSICPSR), offset 0x010 SSICPSR is the clock prescale register and specifies the division factor by which the system clock must be internally divided before further use. The value programmed into this register must be an even number between 2 and 254. The least-significant bit of the programmed number is hard-coded to zero. If an odd number is written to this register, data read back from this register has the least-significant bit as zero.
SSI Clock Prescale (SSICPSR)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0
CPSDVSR
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:8 7:0
Name reserved CPSDVSR
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Clock Prescale Divisor This value must be an even number from 2 to 254, depending on the frequency of SSICLK. The LSB always returns 0 on reads.
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Synchronous Serial Interface (SSI)
Register 6: SSI Interrupt Mask (SSIIM), offset 0x014 The SSIIM register is the interrupt mask set or clear register. It is a read/write register and all bits are cleared to 0 on reset. On a read, this register gives the current value of the mask on the relevant interrupt. A write of 1 to the particular bit sets the mask, enabling the interrupt to be read. A write of 0 clears the corresponding mask.
SSI Interrupt Mask (SSIIM)
Offset 0x014
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TXIM
R/W 0
RXIM
R/W 0
RTIM
R/W 0
RORIM
R/W 0
Bit/Field 31:4 3
Name reserved TXIM
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Transmit FIFO Interrupt Mask 0: TX FIFO half-full or less condition interrupt is masked. 1: TX FIFO half-full or less condition interrupt is not masked.
2
RXIM
R/W
0
SSI Receive FIFO Interrupt Mask 0: RX FIFO half-full or more condition interrupt is masked. 1: RX FIFO half-full or more condition interrupt is not masked.
1
RTIM
R/W
0
SSI Receive Time-Out Interrupt Mask 0: RX FIFO time-out interrupt is masked. 1: RX FIFO time-out interrupt is not masked.
0
RORIM
R/W
0
SSI Receive Overrun Interrupt Mask 0: RX FIFO overrun interrupt is masked. 1: RX FIFO overrun interrupt is not masked.
292 Preliminary
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LM3S317 Data Sheet
Register 7: SSI Raw Interrupt Status (SSIRIS), offset 0x018 The SSIRIS register is the raw interrupt status register. On a read, this register gives the current raw status value of the corresponding interrupt prior to masking. A write has no effect.
SSI Raw Interrupt Status (SSIRIS)
Offset 0x018
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TXRIS
RO 1
RXRIS
RO 0
RTRIS RORRIS
RO 0 RO 0
Bit/Field 31:4 3
Name reserved TXRIS
Type RO RO
Reset 0 1
Description Reserved bits return an indeterminate value, and should never be changed. SSI Transmit FIFO Raw Interrupt Status Indicates that the transmit FIFO is half full or less, when set.
2
RXRIS
RO
0
SSI Receive FIFO Raw Interrupt Status Indicates that the receive FIFO is half full or more, when set.
1
RTRIS
RO
0
SSI Receive Time-Out Raw Interrupt Status Indicates that the receive time-out has occurred, when set.
0
RORRIS
RO
0
SSI Receive Overrun Raw Interrupt Status Indicates that the receive FIFO has overflowed, when set.
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Synchronous Serial Interface (SSI)
Register 8: SSI Masked Interrupt Status (SSIMIS), offset 0x01C The SSIMIS register is the masked interrupt status register. On a read, this register gives the current masked status value of the corresponding interrupt. A write has no effect.
SSI Masked Interrupt Status (SSIMIS)
Offset 0x01C
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
TXMIS RXMIS
RO 0 RO 0
RTMIS RORMIS
RO 0 RO 0
Bit/Field 31:4 3
Name reserved TXMIS
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Transmit FIFO Masked Interrupt Status Indicates that the transmit FIFO is half full or less, when set.
2
RXMIS
RO
0
SSI Receive FIFO Masked Interrupt Status Indicates that the receive FIFO is half full or more, when set.
1
RTMIS
RO
0
SSI Receive Time-Out Masked Interrupt Status Indicates that the receive time-out has occurred, when set.
0
RORMIS
RO
0
SSI Receive Overrun Masked Interrupt Status Indicates that the receive FIFO has overflowed, when set.
294 Preliminary
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LM3S317 Data Sheet
Register 9: SSI Interrupt Clear (SSIICR), offset 0x020 The SSIICR register is the interrupt clear register. On a write of 1, the corresponding interrupt is cleared. A write of 0 has no effect.
SSI Interrupt Clear (SSIICR)
Offset 0x020
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
RTIC
W1C 0
RORIC
W1C 0
Bit/Field 31:2 1
Name reserved RTIC
Type RO W1C
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. SSI Receive Time-Out Interrupt Clear 0: No effect on interrupt. 1: Clears interrupt.
0
RORIC
W1C
0
SSI Receive Overrun Interrupt Clear 0: No effect on interrupt. 1: Clears interrupt.
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Synchronous Serial Interface (SSI)
Register 10: SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 4 (SSIPeriphID4)
Offset 0xFD0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID4
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID4
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register[7:0]
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LM3S317 Data Sheet
Register 11: SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 5 (SSIPeriphID5)
Offset 0xFD4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID5
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID5
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register[15:8]
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Synchronous Serial Interface (SSI)
Register 12: SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 6 (SSIPeriphID6)
Offset 0xFD8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID6
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID6
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register[23:16]
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LM3S317 Data Sheet
Register 13: SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 7 (SSIPeriphID7)
Offset 0xFDC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID7
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID7
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register[31:24]
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Synchronous Serial Interface (SSI)
Register 14: SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 0 (SSIPeriphID0)
Offset 0xFEO
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0
PID0
RO 0 RO 0 RO 1 RO 0
Bit/Field 31:8 7:0
Name reserved PID0
Type RO RO
Reset 0 0x22
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral.
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LM3S317 Data Sheet
Register 15: SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 1 (SSIPeriphID1)
Offset 0xFE4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID1
Type RO RO
Reset 0 0x00
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register [15:8] Can be used by software to identify the presence of this peripheral.
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Synchronous Serial Interface (SSI)
Register 16: SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 2 (SSIPeriphID2)
Offset 0xFE8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1
PID2
RO 1 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved PID2
Type RO RO
Reset 0 0x18
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register [23:16] Can be used by software to identify the presence of this peripheral.
302 Preliminary
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LM3S317 Data Sheet
Register 17: SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Peripheral Identification 3 (SSIPeriphID3)
Offset 0xFEC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
PID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved PID3
Type RO RO
Reset 0 0x01
Description Reserved bits return an indeterminate value, and should never be changed. SSI Peripheral ID Register [31:24] Can be used by software to identify the presence of this peripheral.
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Synchronous Serial Interface (SSI)
Register 18: SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0 The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Primecell Identification 0 (SSIPCellID0)
Offset 0xFF0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID0
RO 1 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID0
Type RO RO
Reset 0 0x0D
Description Reserved bits return an indeterminate value, and should never be changed. SSI PrimeCell ID Register [7:0] Provides software a standard cross-peripheral identification system.
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LM3S317 Data Sheet
Register 19: SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4 The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Primecell Identification 1 (SSIPCellID1)
Offset 0xFF4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 1
CID1
RO 0 RO 0 RO 0 RO 0
Bit/Field 31:8 7:0
Name reserved CID1
Type RO RO
Reset 0 0xF0
Description Reserved bits return an indeterminate value, and should never be changed. SSI PrimeCell ID Register [15:8] Provides software a standard cross-peripheral identification system.
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Synchronous Serial Interface (SSI)
Register 20: SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8 The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Primecell Identification 2 (SSIPCellID2)
Offset 0xFF8
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CID2
RO 0 RO 1 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID2
Type RO RO
Reset 0 0x05
Description Reserved bits return an indeterminate value, and should never be changed. SSI PrimeCell ID Register [23:16] Provides software a standard cross-peripheral identification system.
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LM3S317 Data Sheet
Register 21: SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value.
SSI Primecell Identification 3 (SSIPCellID3)
Offset 0xFFC
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 RO 1
CID3
RO 0 RO 0 RO 0 RO 1
Bit/Field 31:8 7:0
Name reserved CID3
Type RO RO
Reset 0 0xB1
Description Reserved bits return an indeterminate value, and should never be changed. SSI PrimeCell ID Register [31:24] Provides software a standard cross-peripheral identification system.
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Analog Comparator
14
Analog Comparator
An analog comparator is a peripheral that compares two analog voltages, and provides a logical output that signals the comparison result. The LM3S317 controller provides one analog comparator that can be configured to drive an output or generate an interrupt or ADC event. A comparator can compare a test voltage against any one of these voltages: An individual external reference voltage A shared single external reference voltage A shared internal reference voltage The comparator can provide its output to a device pin, acting as a replacement for an analog comparator on the board, or it can be used to signal the application via interrupts or triggers to the ADC to cause it to start capturing a sample sequence. The interrupt generation and ADC triggering logic is separate. This means, for example, that an interrupt can be generated on a rising edge and the ADC triggered on a falling edge.
14.1
Block Diagram
Figure 14-1. Analog Comparator Module Block Diagram
C0C0+ -ve input +ve input Comparator 0 output C0o
+ve input (alternate) ACCTL0 ACSTAT0 interrupt reference input interrupt
Voltage Ref internal bus ACREFCTL
14.2
Functional Description
Important: It is recommended that the Digital-Input enable (the GPIODEN bit in the GPIO module) for the analog input pin be disabled to prevent excessive current draw from the I/O pads. The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT. As shown in Figure 14-2, the input source for VIN- is an external input. In addition to an external input, input sources for VIN+ can be the +ve input of comparator 0 or an internal reference.
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Figure 14-2. Structure of Comparator Unit
-ve input +ve input
0
output CINV IntGen TrigGen
+ve input (alternate)
1
reference input
2
ACCTL
ACSTAT
A comparator is configured through two status/control registers (ACCTL and ACSTAT). The internal reference is configured through one control register (ACREFCTL). Interrupt status and control is configured through three registers (ACMIS, ACRIS, and ACINTEN). The operating modes of the comparators are shown in Table 14-1. Typically, the comparator output is used internally to generate controller interrupts. It may also be used to drive an external pin or generate an analog-to-digital converter (ADC) trigger. Important: Certain register bit values must be set before using the analog comparators. The proper pad configuration for the comparator input and output pins are described in Table 8-1 on page 119. Table 14-1. Comparator 0 Operating Modes
Comparator 0 VINC0C0C0C0VIN+ C0+ C0+ Vref reserved Output C0o C0o C0o C0o Interrupt yes yes yes yes
ACCNTL0 ASRCP 00 01 10 11
14.2.1
Internal Reference Programming
The structure of the internal reference is shown in Figure 14-3. This is controlled by a single configuration register (ACREFCTL). Table 14-2 shows the programming options to develop specific internal reference values, to compare an external voltage against a particular voltage generated internally.
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internal bus
trigger
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Analog Comparator
Figure 14-3. Comparator Internal Reference Structure
AVDD 8R R R *** EN 15 VREF RNG 14 *** Decoder 1 0 internal reference R R 8R
Table 14-2.
Internal Reference Voltage and ACREFCTL Field Values
Output Reference Voltage Based on VREF Field Value
ACREFCTL Register EN Bit Value EN=0 EN=1 RNG Bit Value RNG=X RNG=0 0 V (GND) for any value of VREF; however, it is recommended that RNG=1 and VREF=0 for the least noisy ground reference. Total resistance in ladder is 32 R. R VREF V REF = AV DD x --------------RT ( VREF + 8 ) V REF = AV DD x ----------------------------32 V REF = 0.825 + 0.103 VREF The range of internal reference in this mode is 0.825-2.37 V. RNG=1 Total resistance in ladder is 24 R. R VREF V REF = AV DD x --------------RT ( VREF ) V REF = AV DD x ------------------24 V REF = 0.1375 VREF The range of internal reference for this mode is 0.0-2.0625 V.
14.3
Initialization and Configuration
The following example shows how to configure analog comparator to read back its output value from an internal register. 1. Enable the analog comparator 0 clock by writing a value of 0x00100000 to the RCGC1 register in the System Control module. 2. In the GPIO module, enable the GPIO port/pin associated with C0- as a GPIO input. 3. Configure the internal voltage reference to 1.65 V by writing the ACREFCTL register with the value 0x0000030C. 4. Configure comparator 0 to use the internal voltage reference and to not invert the output on the C0O pin by writing the ACCTL0 register with the value of 0x0000040C.
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LM3S317 Data Sheet
5. Delay for some time. 6. Read the comparator output value by reading the ACSTAT0 register's OVAL value. Change the level of the signal input on C0- to see the OVAL value change.
14.4
Register Map
Table 14-3 lists the comparator registers. The offset listed is a hexadecimal increment to the register's address, relative to the Analog Comparator base address of 0x4003C000.
Table 14-3.
Offset 0x00 0X04 0X08 0x10 0x20 0x24
Analog Comparator Register Map
Name ACMIS ACRIS ACINTEN ACREFCTL ACSTAT0 ACCTL0 Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 Type R/W1C RO R/W R/W RO R/W Description Interrupt status Raw interrupt status Interrupt enable Reference voltage control Comparator 0 status Comparator 0 control See page 312 313 314 315 316 317
14.5
Register Descriptions
The remainder of this section lists and describes the Analog Comparator registers, in numerical order by address offset.
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Register 1: Analog Comparator Masked Interrupt Status (ACMIS), offset 0x00 This register provides a summary of the interrupt status (masked) of the comparator.
Analog Comparator Masked Interrupt Status (ACMIS)
Offset 0x000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IN0
RO 0
Bit/Field 31:1 0
Name reserved IN0
Type RO R/1WC
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Comparator 0 Masked Interrupt Status Gives the masked interrupt state of this interrupt. Write 1 to this field to clear the pending interrupt.
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LM3S317 Data Sheet
Register 2: Analog Comparator Raw Interrupt Status (ACRIS), offset 0x04 This register provides a summary of the interrupt status (raw) of the comparator.
Analog Comparator Raw Interrupt Status (ACRIS)
Offset 0x04
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IN0
RO 0
Bit/Field 31:1 0
Name reserved IN0
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. When set, indicates that an interrupt has been generated by comparator 0.
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Analog Comparator
Register 3: Analog Comparator Interrupt Enable (ACINTEN), offset 0x08 This register provides the interrupt enable for the comparator.
Analog Comparator Interrupt Enable (ACINTEN)
Offset 0x08
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IN0
RO R/W 0
Bit/Field 31:1 0
Name reserved IN0
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. When set, enables the controller interrupt from the comparator 0 output.
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LM3S317 Data Sheet
Register 4: Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x10 This register specifies whether the resistor ladder is powered on as well as the range and tap.
Analog Comparator Reference Voltage Control (ACREFCTL)
Offset 0x010
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved EN RNG
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W RO 0 RO R/W 0 RO 0 RO 0 RO 0 RO 0 RO R/W 0 R/W RO 0
VREF
RO R/W 0 R/W RO 0
Bit/Field 31:10 9
Name reserved EN
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The EN bit specifies whether the resistor ladder is powered on. If 0, the resistor ladder is unpowered. If 1, the resistor ladder is connected to the analog VDD. This bit is reset to 0 so that the internal reference consumes the least amount of power if not used and programmed.
8
RNG
R/W
0
The RNG bit specifies the range of the resistor ladder. If 0, the resistor ladder has a total resistance of 32 R. If 1, the resistor ladder has a total resistance of 24 R. Reserved bits return an indeterminate value, and should never be changed. The VREF bit field specifies the resistor ladder tap that is passed through an analog multiplexer. The voltage corresponding to the tap position is the internal reference voltage available for comparison. See Table 14-2 on page 310 for some output reference voltage examples.
7:4 3:0
reserved VREF
RO R/W
0 0
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Register 5: Analog Comparator Status 0 (ACSTAT0), offset 0x20 This register specifies the current output value of that comparator.
Analog Comparator Status 0 (ACSTAT0)
Offset 0x020
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
OVAL
RO 0
reserved
RO 0
Bit/Field 31:2 1 0
Name reserved OVAL reserved
Type RO RO RO
Reset 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The OVAL bit specifies the current output value of the comparator. Reserved bits return an indeterminate value, and should never be changed.
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LM3S317 Data Sheet
Register 6: Analog Comparator Control 0 (ACCTL0), offset 0x24 This register configures that comparator's input and output.
Analog Comparator Control 0 (ACCTL0)
Offset 0x024
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0
TOEN
R/W 0
ASRCP
RO R/W 0 RO R/W 0
reserved TSLVAL
RO 0 R/W RO 0 RO R/W 0
TSEN
RO R/W 0
ISLVAL
R/W RO 0 RO R/W 0
ISEN
RO R/W 0
CINV
R/W RO 0
reserved
RO RO 0
Bit/Field 31:12 11
Name reserved TOEN
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The TOEN bit enables the ADC event transmission to the ADC. If 0, the event is suppressed and not sent to the ADC. If 1, the event is transmitted to the ADC. The ASRCP field specifies the source of input voltage to the VIN+ terminal of the comparator. The encodings for this field are as follows: ASRCP 00 01 10 11 Function Pin value Pin value of C0+ Internal voltage reference Reserved
10:9
ASRCP
R/W
0
8 7
reserved TSLVAL
RO R/W
0 0
Reserved bits return an indeterminate value, and should never be changed. The TSLVAL bit specifies the sense value of the input that generates an ADC event if in Level Sense mode. If 0, an ADC event is generated if the comparator output is Low. Otherwise, an ADC event is generated if the comparator output is High. The TSEN field specifies the sense of the comparator output that generates an ADC event. The sense conditioning is as follows: TSEN 00 01 10 11 Function Level sense, see TSLVAL Falling edge Rising edge Either edge
6:5
TSEN
R/W
0
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Bit/Field 4
Name ISLVAL
Type R/W
Reset 0
Description The ISLVAL bit specifies the sense value of the input that generates an interrupt if in Level Sense mode. If 0, an interrupt is generated if the comparator output is Low. Otherwise, an interrupt is generated if the comparator output is High. The ISEN field specifies the sense of the comparator output that generates an interrupt. The sense conditioning is as follows: ISEN 00 01 10 11 Function Level sense, see ISLVAL Falling edge Rising edge Either edge
3:2
ISEN
R/W
0
1
CINV
R/W
0
The CINV bit conditionally inverts the output of the comparator. If 0, the output of the comparator is unchanged. If 1, the output of the comparator is inverted prior to being processed by hardware. Reserved bits return an indeterminate value, and should never be changed.
0
reserved
RO
0
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15
Pulse Width Modulator (PWM)
Pulse width modulation (PWM) is a powerful technique for digitally encoding analog signal levels. High-resolution counters are used to generate a square wave, and the duty cycle of the square wave is modulated to encode an analog signal. Typical applications include switching power supplies and motor control. The LM3S317 PWM module consists of PWM generator block and a control block. PWM generator block contains one timer (16-bit down or up/down counter), two comparators, a PWM signal generator, a dead-band generator, and an interrupt selector. The control block determines the polarity of the PWM signals, and which signals are passed through to the pins. PWM generator block produces two PWM signals that can either be independent signals (other than being based on the same timer and therefore having the same frequency) or a single pair of complementary signals with dead-band delays inserted. The output of the PWM generation block managed by the output control block before being passed to the device pins. The LM3S317 PWM module provides a great deal of flexibility. It can generate simple PWM signals, such as those required by a simple charge pump. It can also generate paired PWM signals with dead-band delays, such as those required by a half-H bridge driver.
15.1
Block Diagram
Figure 15-1 provides a block diagram of a Stellaris PWM module. Figure 15-1. PWM Module Block Diagram
15.2
15.2.1
Functional Description
PWM Timer
The timer runs in one of two modes: Count-Down mode or Count-Up/Down mode. In Count-Down mode, the timer counts from the load value to zero, goes back to the load value, and continues counting down. In Count-Up/Down mode, the timer counts from zero up to the load value, back down to zero, back up to the load value, and so on. Generally, Count-Down mode is used for generating left- or right-aligned PWM signals, while the Count-Up/Down mode is used for generating center-aligned PWM signals. The timers output three signals that are used in the PWM generation process: the direction signal (this is always Low in Count-Down mode, but alternates between Low and High in Count-Up/Down mode), a single-clock-cycle-width High pulse when the counter is zero, and a single-clock-cycle-width High pulse when the counter is equal to the load value. Note that in Count-Down mode, the zero pulse is immediately followed by the load pulse.
15.2.2
PWM Comparators
There are two comparators in PWM generator that monitor the value of the counter; when either match the counter, they output a single-clock-cycle-width High pulse. When in Count-Up/Down mode, these comparators match both when counting up and when counting down; they are therefore qualified by the counter direction signal. These qualified pulses are used in the PWM generation process. If either comparator match value is greater than the counter load value, then that comparator never outputs a High pulse. Figure 15-2 shows the behavior of the counter and the relationship of these pulses when the counter is in Count-Down mode. Figure 15-3 shows the behavior of the counter and the relationship of these pulses when the counter is in Count-Up/Down mode.
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Pulse Width Modulator (PWM)
Figure 15-2. PWM Count-Down Mode
Load
CompA CompB
Zero Load Zero A B Dir
BDown ADown
Figure 15-3. PWM Count-Up/Down Mode
Load
CompA CompB
Zero Load Zero A B Dir
BUp AUp
BDown ADown
15.2.3
PWM Signal Generator
The PWM generator takes these pulses (qualified by the direction signal), and generates two PWM signals. In Count-Down mode, there are four events that can affect the PWM signal: zero, load, match A down, and match B down. In Count-Up/Down mode, there are six events that can affect the PWM signal: zero, load, match A down, match A up, match B down, and match B up. The match A or match B events are ignored when they coincide with the zero or load events. If the match A and match B events coincide, the first signal, PWMA, is generated based only on the match A event, and the second signal, PWMB, is generated based only on the match B event. For each event, the effect on each output PWM signal is programmable: it can be left alone (ignoring the event), it can be toggled, it can be driven Low, or it can be driven High. These actions can be used to generate a pair of PWM signals of various positions and duty cycles, which do or do not overlap. Figure 15-4 shows the use of Count-Up/Down mode to generate a pair of center-aligned, overlapped PWM signals that have different duty cycles.
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LM3S317 Data Sheet
Figure 15-4. PWM Generation Example In Count-Up/Down Mode
Load
CompA CompB
Zero PWMA PWMB
In this example, the first generator is set to drive High on match A up, drive Low on match A down, and ignore the other four events. The second generator is set to drive High on match B up, drive Low on match B down, and ignore the other four events. Changing the value of comparator A changes the duty cycle of the PWMA signal, and changing the value of comparator B changes the duty cycle of the PWMB signal.
15.2.4
Dead-Band Generator
The two PWM signals produced by the PWM generator are passed to the dead-band generator. If disabled, the PWM signals simply pass through unmodified. If enabled, the second PWM signal is lost and two PWM signals are generated based on the first PWM signal. The first output PWM signal is the input signal with the rising edge delayed by a programmable amount. The second output PWM signal is the inversion of the input signal with a programmable delay added between the falling edge of the input signal and the rising edge of this new signal. This is therefore a pair of active High signals where one is always High, except for a programmable amount of time at transitions where both are Low. These signals are therefore suitable for driving a half-H bridge, with the dead-band delays preventing shoot-through current from damaging the power electronics. Figure 15-5 shows the effect of the dead-band generator on an input PWM signal. Figure 15-5. PWM Dead-Band Generator
Input PWMA PWMB Rising Edge Delay Falling Edge Delay
15.2.5
Interrupt Selector
The PWM generator also takes the same four (or six) counter events and uses them to generate an interrupt. Any of these events or a set of these events can be selected as a source for an interrupt; when any of the selected events occur, an interrupt is generated. The selection of events allows the interrupt to occur at a specific position within the PWM signal. Note that interrupts are based on the raw events; delays in the PWM signal edges caused by the dead-band generator are not taken into account.
15.2.6
Synchronization Methods
There is a global reset capability that can synchronously reset any or all of the counters in the PWM generator.
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Pulse Width Modulator (PWM)
The counter load values and comparator match values of the PWM generator can be updated in two ways. The first is immediate update mode, where a new value is used as soon as the counter reaches zero. By waiting for the counter to reach zero, a guaranteed behavior is defined, and overly short or overly long output PWM pulses are prevented. The other update method is synchronous, where the new value is not used until a global synchronized update signal is asserted, at which point the new value is used as soon as the counter reaches zero. This second mode allows multiple items to be updated simultaneously without odd effects during the update; everything runs from the old values until a point at which they all run from the new values.
15.2.7
Fault Conditions
There are two external conditions that affect the PWM block; the signal input on the Fault pin and the stalling of the controller by a debugger. There are two mechanisms available to handle such conditions: the output signals can be forced into an inactive state and/or the PWM timers can be stopped. Each output signal has a fault bit. If set, a fault input signal causes the corresponding output signal to go into the inactive state. If the inactive state is a safe condition for the signal to be in for an extended period of time, this keeps the output signal from driving the outside world in a dangerous manner during the fault condition. A fault condition can also generate a controller interrupt. Each PWM generator can also be configured to stop counting during a stall condition. The user can select for the counters to run until they reach zero then stop, or to continue counting and reloading. A stall condition does not generate a controller interrupt.
15.2.8
Output Control Block
With PWM generator block producing two raw PWM signals, the output control block takes care of the final conditioning of the PWM signals before they go to the pins. Via a single register, the set of PWM signals that are actually enabled to the pins can be modified; this can be used, for example, to perform commutation of a brushless DC motor with a single register write (and without modifying the individual PWM generators, which are modified by the feedback control loop). Similarly, fault control can disable any of the PWM signals as well. A final inversion can be applied to any of the PWM signals, making them active Low instead of the default active High.
15.3
Initialization and Configuration
The following example shows how to initialize the PWM Generator 0 with a 25-KHz frequency, and with a 25% duty cycle on the PWM0 pin and a 75% duty cycle on the PWM1 pin. This example assumes the system clock is 20 MHz. 1. Enable the PWM clock by writing a value of 0x00100000 to the RCGC0 register in the System Control module. 2. In the GPIO module, enable the appropriate pins for their alternate function using the GPIOAFSEL register. 3. Configure the Run-Mode Clock Configuration (RCC) register in the System Control module to use the PWM divide (USEPWMDIV) and set the divider (PWMDIV) to divide by 2 (000). 4. Configure the PWM generator for countdown mode with immediate updates to the parameters. - Write the PWM0CTL register with a value of 0x00000000. - Write the PWM0GENA register with a value of 0x0000008C. - Write the PWM0GENB register with a value of 0x0000080C.
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LM3S317 Data Sheet
5. Set the period. For a 25-KHz frequency, the period = 1/25,000, or 40 microseconds. The PWM clock source is 10 MHz; the system clock divided by 2. This translates to 400 clock ticks per period. Use this value to set the PWM0LOAD register. In Count-Down mode, set the LOAD field in the PWM0LOAD register to the requested period minus one. - Write the PWM0LOAD register with a value of 0x0000018F. 6. Set the pulse width of the PWM0 pin for a 25% duty cycle. - Write the PWM0CMPA register with a value of 0x0000012B. 7. Set the pulse width of the PWM1 pin for a 75% duty cycle. - Write the PWM0CMPB register with a value of 0x00000063. 8. Start the timers in PWM generator 0. - Write the PWM0CTL register with a value of 0x00000001. 9. Enable PWM outputs. - Write the PWMENABLE register with a value of 0x00000003.
15.4
Register Map
Table 15-2 lists the PWM registers. The offset listed is a hexadecimal increment to the register's address, relative to the PWM base address of 0x40028000.
Table 15-1.
Offset
PWM Register Map (Sheet 1 of 2)
Name Reset Type Description See page
PWM Module Control 0x000 0x004 0x008 0x00C 0x010 0x014 0x018 0x01C 0x020 PWMCTL PWMSYNC PWMENABLE PWMINVERT PWMFAULT PWMINTEN PWMRIS PWMISC PWMSTATUS 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 R/W R/W R/W R/W R/W R/W RO R/W1C RO Master control of the PWM module Counter synchronization for the PWM generators Master enable for the PWM output pins Inversion control for the PWM output pins Fault handling for the PWM output pins Interrupt enable Raw interrupt status Interrupt status and clear Value of the Fault input signal 325 326 327 328 329 330 331 332 333
PWM Generator 0 0x040 0x044 0x048 0x04C 0x050 PWM0CTL PWM0INTEN PWM0RIS PWM0ISC PWM0LOAD 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 R/W R/W RO R/W1C R/W Master control of the PWM0 generator block Interrupt enable Raw interrupt status Interrupt status and clear Load value for the counter 334 335 336 337 338
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Pulse Width Modulator (PWM)
Table 15-1.
Offset 0x054 0x058 0x05C 0x060 0x064 0x068 0x06C 0x070
PWM Register Map (Sheet 2 of 2)
Name PWM0COUNT PWM0CMPA PWM0CMPB PWM0GENA PWM0GENB PWM0DBCTL PWM0DBRISE PWM0DBFALL Reset 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 Type RO R/W R/W R/W R/W R/W R/W R/W Description Current counter value Comparator A value Comparator B value Controls PWM generator A Controls PWM generator B Control the dead-band generator Dead-band rising-edge delay count Dead-band falling-edge delay count See page 338 340 341 342 344 345 346 347
15.5
Register Descriptions
The remainder of this section lists and describes the PWM registers, in numerical order by address offset.
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LM3S317 Data Sheet
Register 1: PWM Master Control (PWMCTL), offset 0x000 This register provides master control over the PWM generation block.
Bit/Field 31: 0 Name reserved GlobalSync0 Type RO R/W Reset 0 0 Description Reserved bits return an indeterminate value, and should never be changed. Setting this bit causes any queued update to a load or comparator register in PWM generator 0 to be applied the next time the corresponding counter becomes zero. This bit automatically clears when the updates have completed; it cannot be cleared by software.
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Pulse Width Modulator (PWM)
Register 2: PWM Time Base Sync (PWMSYNC), offset 0x004 This register provides a method to perform synchronization of the counters in the PWM generation blocks. Writing a bit in this register to 1 causes the specified counter to reset back to 0; writing multiple bits resets multiple counters simultaneously. The bits auto-clear after the reset has occurred; reading them back as zero indicates that the synchronization has completed.
Bit/Field 31: 0 Name reserved Sync0 Type RO R/W Reset 0 0 Description Reserved bits return an indeterminate value, and should never be changed. Performs a reset of the PWM generator 0 counter.
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LM3S317 Data Sheet
Register 3: PWM Output Enable (PWMENABLE), offset 0x008 This register provides a master control of which generated PWM signals are output to device pins. By disabling a PWM output, the generation process can continue (for example when the time bases are synchronized) without driving PWM signals to the pins. When bits in this register are set, the corresponding PWM signal is passed through to the output stage, which is controlled by the PWMINVERT register. When bits are not set, the PWM signal is replaced by a zero value which is also passed to the output stage.
Bit/Field 31: 1 0 Name reserved PWM1En PWM0En Type RO R/W R/W Reset 0 0 0 Description Reserved bits return an indeterminate value, and should never be changed. When set, allows the generated PWM1 signal to be passed to the device pin. When set, allows the generated PWM0 signal to be passed to the device pin.
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Pulse Width Modulator (PWM)
Register 4: PWM Output Inversion (PWMINVERT), offset 0x00C This register provides a master control of the polarity of the PWM signals on the device pins. The PWM signals generated by the dead-band block are active High; they can optionally be made active Low via this register. Disabled PWM channels are also passed through the output inverter (if so configured) so that inactive channels maintain the correct polarity.
Bit/Field 31: 1 0 Name reserved PWM1Inv PWM0Inv Type RO R/W R/W Reset 0 0 0 Description Reserved bits return an indeterminate value, and should never be changed. When set, the generated PWM1 signal is inverted. When set, the generated PWM0 signal is inverted.
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LM3S317 Data Sheet
Register 5: PWM Output Fault (PWMFAULT), offset 0x010 This register controls the behavior of the PWM outputs in the presence of fault conditions. Both the fault input and debug events are considered fault conditions. On a fault condition, each PWM signal can either be passed through unmodified or driven Low. For outputs that are configured for pass-through, the debug event handling on the corresponding PWM generator also determines if the PWM signal continues to be generated. Fault condition control happens before the output inverter, so PWM signals driven Low on fault are inverted if the channel is configured for inversion (therefore, the pin is driven High on a fault condition).
Bit/Field 31: 1 0 Name reserved Fault1 Fault0 Type RO R/W R/W Reset 0 0 0 Description Reserved bits return an indeterminate value, and should never be changed. When set, the PWM1 output signal is driven Low on a fault condition. When set, the PWM0 output signal is driven Low on a fault condition.
May 4, 2007 Preliminary
329
Pulse Width Modulator (PWM)
Register 6: PWM Interrupt Enable (PWMINTEN), offset 0x014 This register controls the global interrupt generation capabilities of the PWM module. The events that can cause an interrupt are the fault input and the individual interrupts from the PWM generator.
Bit/Field 31:17 16 15: 0 Name reserved IntFault reserved IntPWM0 Type RO R/W RO R/W Reset 0 0 0 0 Description Reserved bits return an indeterminate value, and should never be changed. When 1, an interrupt occurs when the fault input is asserted. Reserved bits return an indeterminate value, and should never be changed. When 1, an interrupt occurs when the PWM generator 0 block asserts an interrupt.
330 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 7: PWM Raw Interrupt Status (PWMRIS), offset 0x018 This register provides the current set of interrupt sources that are asserted, regardless of whether they cause an interrupt to be asserted to the controller. The fault interrupt is latched on detection; it must be cleared through the PWM Interrupt Status and Clear (PWMISC) register (see page 332). The PWM generator interrupts simply reflect the status of the PWM generator; they are cleared via the interrupt status register in the PWM generator block. Bits set to 1 indicate the events that are active; a zero bit indicates that the event in question is not active.
May 4, 2007 Preliminary
331
Pulse Width Modulator (PWM)
Register 8: PWM Interrupt Status and Clear (PWMISC), offset 0x01C This register provides a summary of the interrupt status of the PWM generator block. A bit set to 1 indicates that the generator block is asserting an interrupt. The individual interrupt status registers must be consulted to determine the reason for the interrupt, and used to clear the interrupt. For the fault interrupt, a write of 1 to that bit position clears the latched interrupt status.
Bit/Field 31:17 16 15: 0 Name reserved IntFault reserved IntPWM0 Type RO R/W1C RO RO Reset 0 0 0 0 Description Reserved bits return an indeterminate value, and should never be changed. Indicates if the fault input is asserting an interrupt. Reserved bits return an indeterminate value, and should never be changed. Indicates if the PWM generator 0 block is asserting an interrupt.
332 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 9: PWM Status (PWMSTATUS), offset 0x020 This register provides the status of the Fault input signal.
PWM Status (PWMSTATUS)
Offset 0x020
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
Fault
RO 0
Bit/Field 31:1 0
Name reserved Fault
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. When set to 1, indicates the fault input is asserted.
May 4, 2007 Preliminary
333
Pulse Width Modulator (PWM)
Register 10: PWM0 Control (PWM0CTL), offset 0x040 The Register Update mode, Debug mode, Counting mode, and Block Enable mode are all controlled via . The block produce the PWM signals, which can be either two independent PWM signals (from the same counter), or a paired set of PWM signals with dead-band delays added.
PWMn Control (PWMnCTL)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
CmpBUpd CmpAUpd LoadUpd
R/W 0 R/W 0 R/W 0
Debug
R/W 0
Mode
R/W 0
Enable
R/W 0
Bit/Field 31:6 5 4
Name reserved CmpBUpd CmpAUpd
Type RO R/W R/W
Reset 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Same as CmpAUpd but for the comparator B register. The Update mode for the comparator A register. If 0, updates to the register are reflected to the comparator the next time the counter is 0. If 1, updates to the register are delayed until the next time the counter is 0 after a synchronous update has been requested through the PWM Master Control (PWMCTL) register (see page 325). The Update mode for the load register. If 0, updates to the register are reflected to the counter the next time the counter is 0. If 1, updates to the register are delayed until the next time the counter is 0 after a synchronous update has been requested through the PWM Master Control (PWMCTL) register. The behavior of the counter in Debug mode. If 0, the counter stops running when it next reaches 0, and continues running again when no longer in Debug mode. If 1, the counter always runs. The mode for the counter. If 0, the counter counts down from the load value to 0 and then wraps back to the load value (Count-Down mode). If 1, the counter counts up from 0 to the load value, back down to 0, and then repeats (Count-Up/Down mode). Master enable for the PWM generation block. If 0, the entire block is disabled and not clocked. If 1, the block is enabled and produces PWM signals.
3
LoadUpd
R/W
0
2
Debug
R/W
0
1
Mode
R/W
0
0
Enable
R/W
0
334 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 11: PWM0 Interrupt Enable (PWM0INTEN), offset 0x044 These registers control the interrupt generation capabilities of the PWM generator. The events that can cause an interrupt are: The counter being equal to the load register The counter being equal to zero The counter being equal to the comparator A register while counting up The counter being equal to the comparator A register while counting down The counter being equal to the comparator B register while counting up The counter being equal to the comparator B register while counting down Any combination of these events can generate either an interrupt.
Bit/Field 31: 5 4 3 2 1 0 Name reserved IntCmpBD IntCmpBU IntCmpAD IntCmpAU IntCntLoad IntCntZero Type RO R/W R/W R/W R/W R/W R/W Reset 0 0 0 0 0 0 0 Description Reserved bits return an indeterminate value, and should never be changed. When 1, an interrupt occurs when the counter matches the comparator B value and the counter is counting down. When 1, an interrupt occurs when the counter matches the comparator B value and the counter is counting up. When 1, an interrupt occurs when the counter matches the comparator A value and the counter is counting down. When 1, an interrupt occurs when the counter matches the comparator A value and the counter is counting up. When 1, an interrupt occurs when the counter matches the PWMnLOAD register. When 1, an interrupt occurs when the counter is 0.
May 4, 2007 Preliminary
335
Pulse Width Modulator (PWM)
Register 12: PWM0 Raw Interrupt Status (PWM0RIS), offset 0x048 provide the current set of interrupt sources that are asserted, regardless of whether they cause an interrupt to be asserted to the controller. Bits set to 1 indicate the latched events that have occurred; a 0 bit indicates that the event in question has not occurred.
PWMn Raw Interrupt Status (PWMnRIS)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IntCmpBD IntCmpBU IntCmpAD IntCmpAU IntCntLoad IntCntZero
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
Bit/Field 31:6 5 4 3 2 1 0
Name reserved IntCmpBD IntCmpBU IntCmpAD IntCmpAU IntCntLoad IntCntZero
Type RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Indicates that the counter has matched the comparator B value while counting down. Indicates that the counter has matched the comparator B value while counting up. Indicates that the counter has matched the comparator A value while counting down. Indicates that the counter has matched the comparator A value while counting up. Indicates that the counter has matched the PWMnLOAD register. Indicates that the counter has matched 0.
336 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 13: PWM0 Interrupt Status and Clear (PWM0ISC), offset 0x04C provide the current set of interrupt sources that are asserted to the controller. Bits set to 1 indicate the latched events that have occurred; a 0 bit indicates that the event in question has not occurred. These are R/W1C registers; writing a 1 to a bit position clears the corresponding interrupt reason.
PWMn Interrupt Status (PWMnISC)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
IntCmpBD IntCmpBU IntCmpAD IntCmpAU IntCntLoad IntCntZero
R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0
Bit/Field 31:6 5 4 3 2 1 0
Name reserved IntCmpBD IntCmpBU IntCmpAD IntCmpAU IntCntLoad IntCntZero
Type RO R/W1C R/W1C R/W1C R/W1C R/W1C R/W1C
Reset 0 0 0 0 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. Indicates that the counter has matched the comparator B value while counting down. Indicates that the counter has matched the comparator B value while counting up. Indicates that the counter has matched the comparator A value while counting down. Indicates that the counter has matched the comparator A value while counting up. Indicates that the counter has matched the PWMnLOAD register. Indicates that the counter has matched 0.
May 4, 2007 Preliminary
337
Pulse Width Modulator (PWM)
Register 14: PWM0 Load (PWM0LOAD), offset 0x050 contain the load value for the PWM counter. Based on the counter mode, either this value is loaded into the counter after it reaches zero, or it is the limit of up-counting after which the counter decrements back to zero. If the Load Value Update mode is immediate, this value is used the next time the counter reaches zero; if the mode is synchronous, it is used the next time the counter reaches zero after a synchronous update has been requested through the PWM Master Control (PWMCTL) register (see page 325). If this register is re-written before the actual update occurs, the previous value is never used and is lost.
PWMn Load (PWMnLOAD)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
Load
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:0
Name reserved Load
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The counter load value.
338 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 15: PWM0 Counter (PWM0COUNT), offset 0x054 contain the current value of the PWM counter. When this value matches the load register, a pulse is output; this can drive the generation of a PWM signal (via the PWMnGENA/PWMnGENB registers, see page 342 and 344) or drive an interrupt (via the PWMnINTEN register, see page 335). A pulse with the same capabilities is generated when this value is zero.
PWMn Counter (PWMnCOUNT)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
Count
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
Bit/Field 31:16 15:0
Name reserved Count
Type RO RO
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The current value of the counter.
May 4, 2007 Preliminary
339
Pulse Width Modulator (PWM)
Register 16: PWM0 Compare A (PWM0CMPA), offset 0x058 contain a value to be compared against the counter. When this value matches the counter, a pulse is output; this can drive the generation of a PWM signal (via the PWMnGENA/PWMnGENB registers) or drive an interrupt (via the PWMnINTEN register). If the value of this register is greater than the PWMnLOAD register (see page 338), then no pulse is ever output. For comparator A, if the update mode is immediate (based on the CmpAUpd bit in the PWMnCTL register), then this 16-bit CompA value is used the next time the counter reaches zero. If the update mode is synchronous, it is used the next time the counter reaches zero after a synchronous update has been requested through the PWM Master Control (PWMCTL) register (see page 325). If this register is rewritten before the actual update occurs, the previous value is never used and is lost.
PWMn Compare A (PWMnCMPA)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
CompA
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:0
Name reserved CompA
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The value to be compared against the counter.
340 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 17: PWM0 Compare B (PWM0CMPB), offset 0x05C contain a value to be compared against the counter. When this value matches the counter, a pulse is output; this can drive the generation of a PWM signal (via the PWMnGENA/PWMnGENB registers) or drive an interrupt (via the PWMnINTEN register). If the value of this register is greater than the PWMnLOAD register, then no pulse is ever output. For comparator B, if the update mode is immediate (based on the CmpBUpd bit in the PWMnCTL register), then this 16-bit CompB value is used the next time the counter reaches zero after a synchronous update has been requested through the PWM Master Control (PWMCTL) register (see page 325). If this register is rewritten before the actual update occurs, the previous value is never used and is lost.
PWMn Compare B (PWMnCMPB)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
CompB
Type Reset
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:16 15:0
Name reserved CompB
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The value to be compared against the counter.
May 4, 2007 Preliminary
341
Pulse Width Modulator (PWM)
Register 18: PWM0 Generator A Control (PWM0GENA), offset 0x060 control the generation of the PWMNA signal based on the load and zero output pulses from the counter, as well as the compare A and compare B pulses from the comparators. When the counter is running in Count-Down mode, only four of these events occur; when running in Count-Up/Down mode, all six occur. These events provide great flexibility in the positioning and duty cycle of the PWM signal that is produced. The PWM0GENA register controls generation of the PWM0A signal. Each field can take on one of the values defined in Table 15-2, which defines the effect of the event on the output signal. If a zero or load event coincides with a compare A or compare B event, the zero or load action is taken and the compare A or compare B action is ignored. If a compare A event coincides with a compare B event, the compare A action is taken and the compare B action is ignored.
PWMn Generator A Control (PWMnGENA)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0
ActCmpBD
R/W 0 R/W 0
ActCmpBU
R/W 0 R/W 0
ActCmpAD
R/W 0 R/W 0
ActCmpAU
R/W 0 R/W 0
ActLoad
R/W 0 R/W 0
ActZero
R/W 0 R/W 0
Bit/Field 31:12 11:10 9:8
Name reserved ActCmpBD ActCmpBU
Type RO R/W R/W
Reset 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The action to be taken when the counter matches comparator B while counting down. The action to be taken when the counter matches comparator B while counting up. Occurs only when the Mode bit in the PWMnCTL register (see page 334) is set to 1. The action to be taken when the counter matches comparator A while counting down. The action to be taken when the counter matches comparator A while counting up.Occurs only when the Mode bit in the PWMnCTL register is set to 1. The action to be taken when the counter matches the load value. The action to be taken when the counter is zero.
7:6 5:4
ActCmpAD ActCmpAU
R/W R/W
0 0
3:2 1:0
ActLoad ActZero
R/W R/W
0 0
342 Preliminary
May 4, 2007
LM3S317 Data Sheet
Table 15-2.
Value 00 01 10 11
PWM Generator Action Encodings
Description Do nothing. Invert the output signal. Set the output signal to 0. Set the output signal to 1.
May 4, 2007 Preliminary
343
Pulse Width Modulator (PWM)
Register 19: PWM0 Generator B Control (PWM0GENB), offset 0x064 control the generation of the PWMNB signal based on the load and zero output pulses from the counter, as well as the compare A and compare B pulses from the comparators. When the counter is running in Down mode, only four of these events occur; when running in Up/Down mode, all six occur. These events provide great flexibility in the positioning and duty cycle of the PWM signal that is produced. The PWM0GENB register controls generation of the PWM0B signal. Each field can take on one of the values defined in Table 15-2 on page 343, which defines the effect of the event on the output signal. If a zero or load event coincides with a compare A or compare B event, the zero or load action is taken and the compare A or compare B action is ignored. If a compare A event coincides with a compare B event, the compare B action is taken and the compare A action is ignored.
PWMn Generator B Control (PWMnGENB)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0
ActCmpBD
R/W 0 R/W 0
ActCmpBU
R/W 0 R/W 0
ActCmpAD
R/W 0 R/W 0
ActCmpAU
R/W 0 R/W 0
ActLoad
R/W 0 R/W 0
ActZero
R/W 0 R/W 0
Bit/Field 31:12 11:10 9:8
Name reserved ActCmpBD ActCmpBU
Type RO R/W R/W
Reset 0 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The action to be taken when the counter matches comparator B while counting down. The action to be taken when the counter matches comparator B while counting up. Occurs only when the Mode bit in the PWMnCTL register (see page 334) is set to 1. The action to be taken when the counter matches comparator A while counting down. The action to be taken when the counter matches comparator A while counting up. Occurs only when the Mode bit in the PWMnCTL register is set to 1. The action to be taken when the counter matches the load value. The action to be taken when the counter is 0.
7:6 5:4
ActCmpAD ActCmpAU
R/W R/W
0 0
3:2 1:0
ActLoad ActZero
R/W R/W
0 0
344 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 20: PWM0 Dead-Band Control (PWM0DBCTL), offset 0x068 The PWM0DBCTL register controls the dead-band generator, which produces the PWM0 and PWM1 signals based on the PWM0A and PWM0B signals. When disabled, the PWM0A signal passes through to the PWM0 signal and the PWM0B signal passes through to the PWM1 signal. When enabled, the PWM0B signal is ignored; the PWM0 signal is generated by delaying the rising edge(s) of the PWM0A signal by the value in the PWM0DBRISE register (see page 346), and the PWM1 signal is generated by delaying the falling edge(s) of the PWM0A signal by the value in the PWM0DBFALL register (see page 347).
PWMn Dead-Band Control (PWMnDBCTL)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0
Enable
R/W 0
Bit/Field 31:1 0
Name reserved Enable
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. When set, the dead-band generator inserts dead bands into the output signals; when clear, it simply passes the PWM signals through.
May 4, 2007 Preliminary
345
Pulse Width Modulator (PWM)
Register 21: PWM0 Dead-Band Rising-Edge Delay (PWM0DBRISE), offset 0x06C The PWM0DBRISE register contains the number of clock ticks to delay the rising edge of the PWM0A signal when generating the PWM0 signal. If the dead-band generator is disabled through the PWMnDBCTL register, the PWM0DBRISE register is ignored. If the value of this register is larger than the width of a High pulse on the input PWM signal, the rising-edge delay consumes the entire High time of the signal, resulting in no High time on the output. Care must be taken to ensure that the input High time always exceeds the rising-edge delay.
PWMn Dead-Band Rising-Edge Delay (PWMnDBRISE)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
RiseDelay
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:12 11:0
Name reserved RiseDelay
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The number of clock ticks to delay the rising edge.
346 Preliminary
May 4, 2007
LM3S317 Data Sheet
Register 22: PWM0 Dead-Band Falling-Edge-Delay (PWM0DBFALL), offset 0x070 The PWM0DBFALL register contains the number of clock ticks to delay the falling edge of the PWM0A signal when generating the PWM1 signal. If the dead-band generator is disabled, this register is ignored. If the value of this register is larger than the width of a Low pulse on the input PWM signal, the falling-edge delay consumes the entire Low time of the signal, resulting in no Low time on the output. Care must be taken to ensure that the input Low time always exceeds the falling-edge delay.
PWMn Dead-Band Falling-Edge-Delay Register (PWMnDBFALL)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
reserved
Type Reset
RO 0 15 RO 0 14 RO 0 13 RO 0 12 RO 0 11 RO 0 10 RO 0 9 RO 0 8 RO 0 7 RO 0 6 RO 0 5 RO 0 4 RO 0 3 RO 0 2 RO 0 1 RO 0 0
reserved
Type Reset
RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
FallDelay
R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0
Bit/Field 31:12 11:0
Name reserved FallDelay
Type RO R/W
Reset 0 0
Description Reserved bits return an indeterminate value, and should never be changed. The number of clock ticks to delay the falling edge.
May 4, 2007 Preliminary
347
Pin Diagram
16
Pin Diagram
Figure 16-1 shows the pin diagram and pin-to-signal-name mapping. Figure 16-1. Pin Connection Diagram
PB4/C0PB5/C0o PB6/C0+ PB7/TRST PC0/TCK/SWCLK PC1/TMS/SWDIO PC2/TDI PC3/TDO/SWO
36 35 34 33 32 31 30 29 28 27 26 25
PC5/CCP1 PC4/CCP5 VDD GND PA0/U0Rx PA1/U0Tx PA2/SSIClk PA3/SSIFss
PA4/SSIRx PA5/SSITx VDD GND
13 14 15 16 17 18 19 20 21 22 23 24
ADC0 ADC1 ADC2 ADC3 RST LDO VDD GND OSC0 OSC1 PC7/CCP4 PC6/CCP3
1 2 3 4 5 6 7 8 9 10 11 12
48 47 46 45 44 43 42 41 40 39 38 37
ADC4 ADC5 PD5/CCP2 PD4/CCP0
PE1/PWM5 PE0/PWM4 PB3/Fault PB2 VDD GND PB1/PWM3 PB0/PWM2 PD3 PD2 PD1/PWM1 PD0/PWM0
LM3S317
348 Preliminary
May 4, 2007
LM3S317 Data Sheet
17
Signal Tables
The following tables list the signals available for each pin. Functionality is enabled by software with the GPIOAFSEL register (see page 131). Important: All multiplexed pins are GPIOs by default, with the exception of the five JTAG pins (PB7 and PC[3:0]) which default to the JTAG functionality. shows the pin-to-signal-name mapping, including functional characteristics of the signals. lists the signals in alphabetical order by signal name. groups the signals by functionality, except for GPIOs. lists the GPIO pins and their alternate functionality.
Table 17-1.
Pin Number 1 2 3 4 5 6 7 8 9 10 11
Signals by Pin Number (Sheet 1 of 3)
Pin Name ADC0 ADC1 ADC2 ADC3 RST LDO VDD GND OSC0 OSC1 PC7 CCP4 Pin Type I I I I I I O I/O I/O I/O I/O I/O I/O I/O I/O I/O I Buffer Type Analog Analog Analog Analog TTL Power Power Power Analog Analog TTL TTL TTL TTL TTL TTL TTL TTL Power Power TTL TTL Description Analog-to-digital converter input 0. Analog-to-digital converter input 1. Analog-to-digital converter input 2. Analog-to-digital converter input 3. System reset input. The low drop-out regulator output voltage. This pin requires an external capacitor between the pin and GND of 1 F or greater. Positive supply for logic and I/O pins. Ground reference for logic and I/O pins. Oscillator crystal input or an external clock reference input. Oscillator crystal output. GPIO port C bit 7. Timer 2 capture input, compare output, or PWM output channel 4. GPIO port C bit 6. Timer 1 capture input, compare output, or PWM output channel 3. GPIO port C bit 5. Timer 0 capture input, compare output, or PWM output channel 1. GPIO port C bit 4. Timer 2 capture input, compare output, or PWM output channel 5. Positive supply for logic and I/O pins. Ground reference for logic and I/O pins. GPIO port A bit 0. UART0 receive data input.
12
PC6 CCP3
13
PC5 CCP1
14
PC4 CCP5
15 16 17
VDD GND PA0 U0Rx
May 4, 2007 Preliminary
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Signal Tables
Table 17-1.
Pin Number 18
Signals by Pin Number (Sheet 2 of 3)
Pin Name PA1 U0Tx Pin Type I/O O I/O I/O I/O I/O I/O I I/O O I/O O I/O O I/O I/O I/O O I/O O I/O I/O I I/O O Buffer Type TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL Power Power TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL Power Power TTL TTL TTL TTL TTL GPIO port A bit 1. UART0 transmit data output. GPIO port A bit 2. SSI clock reference (input when in slave mode and output in master mode). GPIO port A bit 3. SSI frame enable (input for an SSI slave device and output for an SSI master device). GPIO port A bit 4. SSI receive data input. GPIO port A bit 5. SSI transmit data output. Positive supply for logic and I/O pins. Ground reference for logic and I/O pins. GPIO port D bit 0. Pulse width modulator channel 0 output. GPIO port D bit 1. Pulse width modulator channel 1 output. GPIO port D bit 2. GPIO port D bit 3. GPIO port B bit 0. Pulse width modulator channel 2 output. GPIO port B bit 1. Pulse width modulator channel 3 output. Ground reference for logic and I/O pins. Positive supply for logic and I/O pins. GPIO port B bit 2. GPIO port B bit 3. Motion control 0 fault. GPIO port E bit 0. Pulse width modulator channel 4 output. Description
19
PA2 SSIClk
20
PA3 SSIFss
21
PA4 SSIRx
22
PA5 SSITx
23 24 25
VDD GND PD0 PWM0
26
PD1 PWM1
27 28 29
PD2 PD3 PB0 PWM2
30
PB1 PWM3
31 32 33 34
GND VDD PB2 PB3 FAULT
35
PE0 PWM4
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LM3S317 Data Sheet
Table 17-1.
Pin Number 36
Signals by Pin Number (Sheet 3 of 3)
Pin Name PE1 PWM5 Pin Type I/O O I/O O O I/O I I/O I I/O I/O I I I/O I I/O I I/O O I/O I I/O I/O I/O I/O I I Buffer Type TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL Analog TTL TTL TTL Analog TTL TTL TTL TTL Analog Analog GPIO port E bit 1. Pulse width modulator channel 5 output. GPIO port C bit 3. JTAG scan test data output. Serial-wire output. GPIO port C bit 2. JTAG scan test data input. GPIO port C bit 1. JTAG scan test mode select input. Serial-wire debug input/output. GPIO port C bit 0. JTAG scan test clock reference input. Serial wire clock reference input. GPIO port B bit 7. JTAG scan test reset input. GPIO port B bit 6. Analog comparator 0 positive-reference input. GPIO port B bit 5. Analog comparator 0 output. GPIO port B bit 4. Analog comparator 0 negative-reference input. GPIO port D bit 4. Timer 0 capture input, compare output, or PWM output channel 0. GPIO port D bit 5. Timer 1 capture input, compare output, or PWM output channel 2. Analog-to-digital converter input 5. Analog-to-digital converter input 4. Description
37
PC3 TDO SWO
38
PC2 TDI
39
PC1 TMS SWDIO
40
PC0 TCK SWCLK
41
PB7 TRST
42
PB6 C0+
43
PB5 C0o
44
PB4 C0-
45
PD4 CCP0
46
PD5 CCP2
47 48
ADC5 ADC4
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Signal Tables
Table 17-2.
Pin Name ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 C0+ C0- C0o CCP0 CCP1 CCP2 CCP3 CCP4 CCP5 Fault GND GND GND GND LDO OSC0 OSC1 PA0 PA1 PA2 PA3 PA4 PA5 PB0
Signals by Signal Name (Sheet 1 of 3)
Pin Number 1 2 3 4 48 47 42 44 43 45 13 46 12 11 14 34 8 16 24 31 6 9 10 17 18 19 20 21 22 29 Pin Type I I I I I I I I O I/O I/O I/O I/O I/O I/O I I O I/O I/O I/O I/O I/O I/O I/O Buffer Type Analog Analog Analog Analog Analog Analog Analog Analog TTL TTL TTL TTL TTL TTL TTL TTL Power Power Power Power Power Analog Analog TTL TTL TTL TTL TTL TTL TTL Description Analog-to-digital converter input 0. Analog-to-digital converter input 1. Analog-to-digital converter input 2. Analog-to-digital converter input 3. Analog-to-digital converter input 4. Analog-to-digital converter input 5. Analog comparator 0 positive-reference input. Analog comparator 0 negative-reference input. Analog comparator 0 output. Timer 0 capture input, compare output, or PWM output channel 0. Timer 0 capture input, compare output, or PWM output channel 1. Timer 1 capture input, compare output, or PWM output channel 2. Timer 1 capture input, compare output, or PWM output channel 3. Timer 2 capture input, compare output, or PWM output channel 4. Timer 2 capture input, compare output, or PWM output channel 5. Motion control 0 fault. Ground reference for logic and I/O pins. Ground reference for logic and I/O pins. Ground reference for logic and I/O pins. Ground reference for logic and I/O pins. The low drop-out regulator output voltage. This pin requires an external capacitor between the pin and GND of 1 F or greater. Oscillator crystal input or an external clock reference input. Oscillator crystal output. GPIO port A bit 0. GPIO port A bit 1. GPIO port A bit 2. GPIO port A bit 3. GPIO port A bit 4. GPIO port A bit 5. GPIO port B bit 0.
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LM3S317 Data Sheet
Table 17-2.
Pin Name PB1 PB2 PB3 PB4 PB5 PB6 PB7 PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7 PD0 PD1 PD2 PD3 PD4 PD5 PE0 PE1 PWM0 PWM1 PWM2 PWM3 PWM4 PWM5 RST
Signals by Signal Name (Sheet 2 of 3)
Pin Number 30 33 34 44 43 42 41 40 39 38 37 14 13 12 11 25 26 27 28 45 46 35 36 25 26 29 30 35 36 5 Pin Type I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O O O O O O O I Buffer Type TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL GPIO port B bit 1. GPIO port B bit 2. GPIO port B bit 3. GPIO port B bit 4. GPIO port B bit 5. GPIO port B bit 6. GPIO port B bit 7. GPIO port C bit 0. GPIO port C bit 1. GPIO port C bit 2. GPIO port C bit 3. GPIO port C bit 4. GPIO port C bit 5. GPIO port C bit 6. GPIO port C bit 7. GPIO port D bit 0. GPIO port D bit 1. GPIO port D bit 2. GPIO port D bit 3. GPIO port D bit 4. GPIO port D bit 5. GPIO port E bit 0. GPIO port E bit 1. Pulse width modulator channel 0 output. Pulse width modulator channel 1 output. Pulse width modulator channel 2 output. Pulse width modulator channel 3 output. Pulse width modulator channel 4 output. Pulse width modulator channel 5 output. System reset input. Description
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Signal Tables
Table 17-2.
Pin Name SSIClk SSIFss SSIRx SSITx SWCLK SWDIO SWO TCK TDI TDO TMS TRST U0Rx U0Tx VDD VDD VDD VDD
Signals by Signal Name (Sheet 3 of 3)
Pin Number 19 20 21 22 40 39 37 40 38 37 39 41 17 18 7 15 23 32 Pin Type I/O I/O I O I I/O O I I O I I I O Buffer Type TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL Power Power Power Power Description SSI clock reference (input when in slave mode and output in master mode). SSI frame enable (input for an SSI slave device and output for an SSI master device). SSI receive data input. SSI transmit data output. Serial wire clock reference input. Serial-wire debug input/output. Serial-wire output. JTAG scan test clock reference input. JTAG scan test data input. JTAG scan test data output. JTAG scan test mode select input. JTAG scan test reset input. UART0 receive data input. UART0 transmit data output. Positive supply for logic and I/O pins. Positive supply for logic and I/O pins. Positive supply for logic and I/O pins. Positive supply for logic and I/O pins.
Table 17-3.
Signals by Function, Except for GPIO (Sheet 1 of 3)
Pin Name ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 Pin Number 1 2 3 4 48 47 Pin Type I I I I I I Buffer Type Analog Analog Analog Analog Analog Analog Description Analog-to-digital converter input 0. Analog-to-digital converter input 1. Analog-to-digital converter input 2. Analog-to-digital converter input 3. Analog-to-digital converter input 4. Analog-to-digital converter input 5.
Function ADC
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LM3S317 Data Sheet
Table 17-3.
Signals by Function, Except for GPIO (Sheet 2 of 3)
Pin Name C0+ C0- C0o Pin Number 42 44 43 45 13 46 12 11 14 40 39 37 40 38 37 39 41 Pin Type I I O I/O I/O I/O I/O I/O I/O I I/O O I I O I I Buffer Type Analog Analog TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL Description Analog comparator 0 positive-reference input. Analog comparator 0 negative-reference input. Analog comparator 0 output. Timer 0 capture input, compare output, or PWM output channel 0. Timer 0 capture input, compare output, or PWM output channel 1. Timer 1 capture input, compare output, or PWM output channel 2. Timer 1 capture input, compare output, or PWM output channel 3. Timer 2 capture input, compare output, or PWM output channel 4. Timer 2 capture input, compare output, or PWM output channel 5. Serial-wire clock reference input. Serial-wire debug input/output. Serial-wire output. JTAG scan test clock reference input. JTAG scan test data input. JTAG scan test data output. JTAG scan test mode select input. JTAG scan test reset input.
Function Analog Comparators
General-Purpose Timers
CCP0 CCP1 CCP2 CCP3 CCP4 CCP5
JTAG/SWD/SWO
SWCLK SWDIO SWO TCK TDI TDO TMS TRST
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Signal Tables
Table 17-3.
Signals by Function, Except for GPIO (Sheet 3 of 3)
Pin Name GND GND GND GND LDO Pin Number 8 16 24 31 6 Pin Type Buffer Type Power Power Power Power Power Description Ground reference for logic and I/O pins. Ground reference for logic and I/O pins. Ground reference for logic and I/O pins. Ground reference for logic and I/O pins. The low drop-out regulator output voltage. This pin requires an external capacitor between the pin and GND of 1 F or greater. Positive supply for logic and I/O pins. Positive supply for logic and I/O pins. Positive supply for logic and I/O pins. Positive supply for logic and I/O pins. Pulse width modulator channel 0 output. Pulse width modulator channel 1 output. Pulse width modulator channel 2 output. Pulse width modulator channel 3 output. Pulse width modulator channel 4 output. Pulse width modulator channel 5 output. SSI clock reference (input when in slave mode and output in master mode). SSI frame enable (input for an SSI slave device and output for an SSI master device). SSI receive data input. SSI transmit data output. Oscillator crystal input or an external clock reference input. Oscillator crystal output. System reset input. UART0 receive data input. UART0 transmit data output.
Function Power
VDD VDD VDD VDD PWM PWM0 PWM1 PWM2 PWM3 PWM4 PWM5 SSI SSIClk SSIFss SSIRx SSITx System Control & Clocks OSC0 OSC1 RST UART U0Rx U0Tx
7 15 23 32 25 26 29 30 35 36 19 20 21 22 9 10 5 17 18
O O O O O O I/O I/O I O I O I I O
Power Power Power Power TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL Analog Analog TTL TTL TTL
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LM3S317 Data Sheet
Table 17-4.
GPIO Pin PA0 PA1 PA2 PA3 PA4 PA5 PB0 PB1 PB2 PB3 PB4 PB5 PB6 PB7 PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7 PD0 PD1 PD2 PD3 PD4 PD5
GPIO Pins and Alternate Functions (Sheet 1 of 2)
Pin Number 17 18 19 20 21 22 29 30 33 34 44 43 42 41 40 39 38 37 14 13 12 11 25 26 27 28 45 46 CCP0 CCP2 FAULT C0C0o C0+ TRST TCK TMS TDI TDO CCP5 CCP1 CCP3 CCP4 PWM0 PWM1 SWO SWCLK SWDIO Multiplexed Function U0Rx U0Tx SSIClk SSIFss SSIRx SSITx PWM2 PWM3 Multiplexed Function
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Signal Tables
Table 17-4.
GPIO Pin PD6 PD7 PE0 PE1 PE2 PE3 PE4 PE5
GPIO Pins and Alternate Functions (Sheet 2 of 2)
Pin Number 47 48 35 36 4 3 2 1 Multiplexed Function ADC5 ADC4 PWM4 PWM5 ADC3 ADC2 ADC1 ADC0 Multiplexed Function
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LM3S317 Data Sheet
18
Table 18-1.
Operating Characteristics
Temperature Characteristics
Symbol TA Value -40 to +85 for industrial Unit C
Characteristic Operating temperature rangea
a. Maximum storage temperature is 150C.
Table 18-2.
Thermal Characteristics
Symbol JA TJ TJMAX Value 76 TA + (PAVG * JA) 105c Unit C/W C C
Characteristic Thermal resistance (junction to ambient)a Average junction temperatureb Maximum junction temperature
a. Junction to ambient thermal resistance JA numbers are determined by a package simulator. b. Power dissipation is a function of temperature. c. TJMAX calculation is based on power consumption values and conditions as specified in "Power Specifications" on page 362 of the data sheet.
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Electrical Characteristics
19
19.1
19.1.1
Electrical Characteristics
DC Characteristics
Maximum Ratings
The maximum ratings are the limits to which the device can be subjected without permanently damaging the device. Note: The device is not guaranteed to operate properly at the maximum ratings. Maximum Ratings
Symbol VDD VIN I I Value 0.0 to +3.6 -0.3 to 5.5 100 100 Unit V V mA mA
Table 19-1.
Characteristica Supply voltage range (VDD) Input voltage Maximum current for pins, excluding pins operating as GPIOs Maximum current for GPIO pins
a. Voltages are measured with respect to GND.
Important: This device contains circuitry to protect the inputs against damage due to high-static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum-rated voltages to this high-impedance circuit. Reliability of operation is enhanced if unused inputs are connected to an appropriate logic voltage level (for example, either GND or VDD).
19.1.2
Recommended DC Operating Conditions
Table 19-2.
Parameter VDD VIH VIL VSIH VSIL VOH VOL
Recommended DC Operating Conditions
Parameter Name Supply voltage High-level input voltage Low-level input voltage
High-level input voltage for Schmitt trigger inputs Low-level input voltage for Schmitt trigger inputs
Min 3.0 2.0 -0.3 0.8 * VDD 0 2.4 -
Nom 3.3 -
Max 3.6 5.0 1.3 VDD 0.2 * VDD 0.4
Unit V V V V V V V
High-level output voltage Low-level output voltage
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LM3S317 Data Sheet
Table 19-2.
Parameter IOH
Recommended DC Operating Conditions (Continued)
Parameter Name High-level source current, VOH=2.4 V 2-mA Drive 4-mA Drive 8-mA Drive 2.0 4.0 8.0 mA mA mA Min Nom Max Unit
IOL
Low-level sink current, VOL=0.4 V 2-mA Drive 4-mA Drive 8-mA Drive 2.0 4.0 8.0 mA mA mA
19.1.3
On-Chip Low Drop-Out (LDO) Regulator Characteristics
Table 19-3.
Parameter VLDOOUT
LDO Regulator Characteristics
Parameter Name Programmable internal (logic) power supply output value Output voltage accuracy Min 2.25 Nom 2% 50 1 Max 2.75 100 200 100 Unit V % s s s mV F
tPON tON tOFF VSTEP CLDO
Power-on time Time on Time off Step programming incremental voltage External filter capacitor size for internal power supply
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Electrical Characteristics
19.1.4
Power Specifications
The power measurements specified in Table 19-4 are run on the core processor using SRAM with the following specifications: VDD = 3.3 V Temperature = 25C Table 19-4.
Parameter IDD_RUN
Power Specifications
Parameter Name Run mode 1 (Flash loop) LDO = 2.50 V Code = while(1){} executed in Flash Peripherals = All clock-gated ON System Clock = 25 MHz (with PLL) Run mode 2 (Flash loop) LDO = 2.50 V Code = while(1){} executed in Flash Peripherals = All clock-gated OFF System Clock = 25 MHz (with PLL) Run mode 1 (SRAM loop) LDO = 2.50 V Code = while(1){} executed in SRAM Peripherals = All clock-gated ON System Clock = 25 MHz (with PLL) Run mode 2 (SRAM loop) LDO = 2.50 V Code = while(1){} executed in SRAM Peripherals = All clock-gated OFF System Clock = 25 MHz (with PLL) 30 35 mA 50 55 mA 40 45 mA Conditions Nom 60 Max 65 Unit mA
IDD_SLEEP
Sleep mode
LDO = 2.50 V Peripherals = All clock-gated OFF System Clock = 25 MHz (with PLL)
18
21
mA
IDD_DEEPSLEEP
Deep-Sleep mode
LDO = 2.25 V Peripherals = All clock-gated OFF System Clock = MOSC/16
950
1150
A
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LM3S317 Data Sheet
19.1.5
Flash Memory Characteristics
Table 19-5.
Parameter PECYC TRET TPROG TERASE TME
Flash Memory Characteristics
Parameter Name Number of guaranteed program/erase cyclesa before failure Data retention at average operating temperature of 85C Word program time Page erase time Mass erase time Min 10,000 10 20 20 200 Nom Max Unit cycles years s ms ms
a. A program/erase cycle is defined as switching the bits from 1-> 0 -> 1.
19.2
19.2.1
AC Characteristics
Load Conditions
Unless otherwise specified, the following conditions are true for all timing measurements. Timing measurements are for 4-mA drive strength. Figure 19-1. Load Conditions
pin
CL = 50 pF
GND
19.2.2
Clocks
Table 19-6. Phase Locked Loop (PLL) Characteristics
Parameter Name Crystal referencea External clock referencea PLL frequency PLL lock time
b
Parameter fREF_CRYSTAL fREF_EXT fPLL TREADY
Min 3.579545 3.579545 -
Nom 200 -
Max 8.192 8.192 0.5
Unit MHz MHz MHz ms
a. The exact value is determined by the crystal value programmed into the XTAL field of the Run-Mode Clock Configuration (RCC) register (see page 83). b. PLL frequency is automatically calculated by the hardware based on the XTAL field of the RCC register.
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Electrical Characteristics
Table 19-7.
Clock Characteristics
Parameter Name Internal oscillator frequency Main oscillator frequency Main oscillator period Crystal reference using the main oscillator (PLL in BYPASS mode)a External clock reference (PLL in BYPASS mode)a System clock Min 7 1 125 1 Nom 15 Max 22 8 1000 8 Unit MHz MHz ns MHz
Parameter fIOSC fMOSC tMOSC_PER fREF_CRYSTAL_BYPASS
fREF_EXT_BYPASS fSYSTEM_CLOCK
0 0
-
25 25
MHz MHz
a. The ADC must be clocked from the PLL or directly from a 14-MHz to 18-MHz clock source in order to operate properly.
19.2.3
Table 19-8.
Analog-to-Digital Converter
ADC Characteristics
Parameter Name Maximum single-ended, full-scale analog input voltage Minimum single-ended, full-scale analog input voltage Maximum differential, full-scale analog input voltage Minimum differential, full-scale analog input voltage Min 3.5 219 Nom 1 10 4 250 Max 3.0 0 1.5 -1.5 4.5 16 281 1 1 +2 2 Unit V V V V pF bits MHz tADC cyclesa k samples/s LSB LSB LSB LSB
Parameter VADCIN
CADCIN N fADC tADCCONV fADCCONV INL DNL OFF GAIN
a. tADC = 1/fADC clock
Equivalent input capacitance Resolution ADC internal clock frequency Conversion time Conversion rate Integral nonlinearity Differential nonlinearity Offset Gain
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LM3S317 Data Sheet
19.2.4
Table 19-9.
Analog Comparator
Analog Comparator Characteristics
Parameter Name Input offset voltage Input common mode voltage range Common mode rejection ratio Response time Comparator mode change to Output Valid Min 0 50 Nom 10 Max 25 VDD-1.5 1 10 Unit mV V dB s s
Parameter VOS VCM CMRR TRT TMC
Table 19-10.
Parameter RHR RLR AHR ALR
Analog Comparator Voltage Reference Characteristics
Parameter Name Resolution high range Resolution low range Absolute accuracy high range Absolute accuracy low range Min Nom VDD/32 VDD/24 Max 1/2 1/4 Unit LSB LSB LSB LSB
19.2.5
Synchronous Serial Interface (SSI)
SSI Characteristics
Parameter tCLK_PER tCLK_HIGH tCLK_LOW tCLKRF tDMD tDMS tDMH tDSS tDSH Parameter Name SSICLK cycle time SSICLK high time SSICLK low time SSICLK rise/fall time Data from master valid delay time Data from master setup time Data from master hold time Data from slave setup time Data from slave hold time Min 2 0 20 40 20 40 Nom 1/2 1/2 7.4 Max 65024 26 20 Unit system clocks tCLK_PER tCLK_PER ns ns ns ns ns ns
Table 19-11.
Parameter No. S1 S2 S3 S4 S5 S6 S7 S8 S9
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Electrical Characteristics
Figure 19-2. SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement
S1 S2 S4
SSIClk
S3
SSIFss SSITx SSIRx
MSB
4 to 16 bits
LSB
Figure 19-3. SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer
S2 S1
SSIClk
S3
SSIFss SSITx
MSB 8-bit control
LSB
SSIRx
0
MSB 4 to 16 bits output data
LSB
Figure 19-4. SSI Timing for SPI Frame Format (FRF=00), with SPH=1
S1 S4 S2
SSIClk (SPO=0)
S3
SSIClk (SPO=1)
S6 S7
SSITx (master)
S5
MSB
S8 S9
LSB LSB
SSIRx (slave) SSIFss
MSB
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LM3S317 Data Sheet
19.2.6
JTAG and Boundary Scan
JTAG Characteristics
Parameter fTCK tTCK tTCK_LOW tTCK_HIGH tTCK_R tTCK_F tTMS_SU tTMS_HLD tTDI_SU tTDI_HLD TCK fall to Data Valid from High-Z Parameter Name TCK operational clock frequency TCK operational clock period TCK clock Low time TCK clock High time TCK rise time TCK fall time TMS setup time to TCK rise TMS hold time from TCK rise TDI setup time to TCK rise TDI hold time from TCK rise 2-mA drive 4-mA drive 8-mA drive 8-mA drive with slew rate control Min 0 100 0 0 20 20 25 25 Nom 1/2 tTCK 1/2 tTCK 23 15 14 18 21 14 13 18 9 7 6 7 100 10 Max 10 10 10 35 26 25 29 35 25 24 28 11 9 8 9 Unit MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
Table 19-12.
Parameter No. J1 J2 J3 J4 J5 J6 J7 J8 J9 J10 J11 tTDO_ZDV
J12 tTDO_DV
TCK fall to Data Valid from Data Valid
2-mA drive 4-mA drive 8-mA drive 8-mA drive with slew rate control
J13 tTDO_DVZ
TCK fall to High-Z from Data Valid
2-mA drive 4-mA drive 8-mA drive 8-mA drive with slew rate control
J14 J15
tTRST tTRST_SU
TRST assertion time TRST setup time to TCK rise
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Electrical Characteristics
Figure 19-5. JTAG Test Clock Input Timing
J2 J3 J4
TCK
J6 J5
Figure 19-6. JTAG Test Access Port (TAP) Timing
TCK
J7 J8 J7 J8
TMS TDI
J11
TMS Input Valid J9 J10
TMS Input Valid J9 J10
TDI Input Valid J12 TDO Output Valid
TDI Input Valid J13 TDO Output Valid
TDO
Figure 19-7. JTAG TRST Timing
TCK
J14 J15
TRST
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LM3S317 Data Sheet
19.2.7
General-Purpose I/O
GPIO Characteristicsa
Parameter Name GPO Rise Time (from 20% to 80% of VDD) Condition 2-mA drive 4-mA drive 8-mA drive 8-mA drive with slew rate control Min Nom 17 9 6 10 17 8 6 11 Max 26 13 9 12 25 12 10 13 Unit ns ns ns ns ns ns ns ns
Table 19-13.
Parameter tGPIOR
tGPIOF
GPO Fall Time (from 80% to 20% of VDD)
2-mA drive 4-mA drive 8-mA drive 8-mA drive with slew rate control
a. All GPIOs are 5 V-tolerant.
19.2.8
Reset
Reset Characteristics
Parameter VTH VBTH TPOR TBOR TIRPOR TIRBOR TIRHWR TIRSWR TIRWDR TIRLDOR TVDDRISE Parameter Name Reset threshold Brown-Out threshold Power-On Reset timeout Brown-Out timeout Internal reset timeout after POR Internal reset timeout after BORa Internal reset timeout after hardware reset (RST pin) Internal reset timeout after software-initiated system reseta Internal reset timeout after watchdog reseta Internal reset timeout after LDO reseta Supply voltage (VDD) rise time (0V-3.3V) Min 2.85 15 2.5 15 2.5 2.5 2.5 Nom 2.0 2.9 10 500 Max 2.95 30 20 30 20 20 20 100 Unit V V ms s ms s ms s s s ms
Table 19-14.
Parameter No. R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11
a. 20 * tMOSC_PER
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Electrical Characteristics
Figure 19-8. External Reset Timing (RST)
RST
R7
/Reset (Internal)
Figure 19-9. Power-On Reset Timing
R1
VDD
R3
/POR (Internal)
R5
/Reset (Internal)
Figure 19-10. Brown-Out Reset Timing
R2
VDD
R4
/BOR (Internal)
R6
/Reset (Internal)
Figure 19-11. Software Reset Timing
SW Reset
R8
/Reset (Internal)
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LM3S317 Data Sheet
Figure 19-12.
Watchdog Reset Timing
WDT Reset (Internal) /Reset (Internal)
Figure 19-13. LDO Reset Timing
R9
LDO Reset (Internal)
R10
/Reset (Internal)
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Package Information
20
Package Information
Figure 20-1. 48-Pin LQFP Package
aaa
bbb
ccc
NOTES:
1. 2. 3. 4. 5.
ddd
SYMBOL
PACKAGE TYPE 48LD LQFP NOM MAX === 1.60 === 0.15 1.40 1.45 9.00 BSC 7.00 BSC 9.00 BSC 7.00 BSC 0.45 0.80 0.75 0.50 BSC 0.17 0.22 0.27 0.17 0.20 0.23 0.09 === 0.20 0.09 === 0.16 Tolerances of form and position 0.20 0.20 0.08 0.08 MIN === 0.05 1.35 NOTE
6.
7. 8. 9.
A A1 A2 D D1 E E1 L e b b1 c c1 aaa bbb ccc ddd
10. 11. 12. 13. 14. 15.
All dimensions are in mm. All dimensioning and tolerancing conform to ANSI Y14.5M-1982. The top package body size may be smaller than the bottom package body size by as much as 0.20. Datums A-B and -D- to be determined at datum plane -H- . To be determined at seating plane -C- . Dimensions D1 and E1 do not include mold protrusion. Allowable protrusion is 0.25 per side. D1 and E1 are maximum plastic body size dimensions including mold mismatch. Surface finish of the package is #24-27 Charmille (1.6-2.3mR0) Pin 1 and ejector pin may be less than 0.1mR0. Dambar removal protrusion does not exceed 0.08. Intrusion does not exceed 0.03. Burr does not exceed 0.08 in any direction. Dimension b does not include Dambar protrusion. Allowable Dambar protrusion shall not cause the lead width to exceed the maximum b dimension by more than 0.08. Dambar cannot be located on the lower radius or the foot. Minimum space between protrusion and adjacent lead is 0.07 for 0.40 and 0.50 pitch package. Corner radius of plastic body does not exceed 0.20. These dimensions apply to the flat section of the lead between 0.10 and 0.25 from the lead tip. A1 is defined as the distance from the seating plane to the lowest point of the package body. Finish of leads is tin plated. All specifications and dimensions are subjected to IPAC'S manufacturing process flow and materials. The packages described in the drawing conform to JEDEC M5-026A. Where discrepancies between the JEDEC and IPAC documents exist, this drawing will take the precedence.
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LM3S317 Data Sheet
Appendix A. Serial Flash Loader
The Stellaris serial flash loader is used to download code to the flash memory of a device without the use of a debug interface. The serial flash loader uses a simple packet interface to provide synchronous communication with the device. The flash loader runs off the crystal and does not enable the PLL, so its speed is determined by the crystal used. The two serial interfaces that can be used are the UART0 and SSI interfaces. For simplicity, both the data format and communication protocol are identical for both serial interfaces.
21.1
Interfaces
Once communication with the flash loader is established via one of the serial interfaces, that interface is used until the flash loader is reset or new code takes over. For example, once you start communicating using the SSI port, communications with the flash loader via the UART are disabled until the device is reset.
21.1.1
UART
The Universal Asynchronous Receivers/Transmitters (UART) communication uses a fixed serial format of 8 bits of data, no parity, and 1 stop bit. The baud rate used for communication is automatically detected by the flash loader and can be any valid baud rate supported by the host and the device. The auto detection sequence requires that the baud rate should be no more than 1/32 the crystal frequency of the board that is running the serial flash loader. This is actually the same as the hardware limitation for the maximum baud rate for any UART on a Stellaris device. In order to determine the baud rate, the serial flash loader needs to determine the relationship between its own crystal frequency and the baud rate. This is enough information for the flash loader to configure its UART to the same baud rate as the host. This automatic baud rate detection allows the host to use any valid baud rate that it wants to communicate with the device. The method used to perform this automatic synchronization relies on the host sending the flash loader two bytes that are both 0x55. This generates a series of pulses to the flash loader that it can use to calculate the ratios needed to program the UART to match the host's baud rate. After the host sends the pattern, it attempts to read back one byte of data from the UART. The flash loader returns the value of 0xCC to indicate successful detection of the baud rate. If this byte is not received after at least twice the time required to transfer the two bytes, the host can resend another pattern of 0x55, 0x55, and wait for the 0xCC byte again until the flash loader acknowledges that it has received a synchronization pattern correctly. For example, the time to wait for data back from the flash loader should be calculated as at least 2*(20(bits/sync)/baud rate (bits/sec)). For a baud rate of 115200, this time is 2*(20/115200) or 0.35ms.
21.1.2
SSI
The Synchronous Serial Interface (SSI) port also uses a fixed serial format for communications, with the framing defined as Motorola format with SPH set to 1 and SPO set to 1. See the section on SSI formats for more details on this transfer protocol. Like the UART, this interface has hardware requirements that limit the maximum speed that the SSI clock can run. This allows the SSI clock to be at most 1/12 the crystal frequency of the board running the flash loader. Since the host device is the master, the SSI on the flash loader device does not need to determine the clock as it is provided directly by the host.
21.2
Packet Handling
All communications, with the exception of the UART auto-baud, are done via defined packets that are acknowledged (ACK) or not acknowledged (NAK) by the devices. The packets use the same
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format for receiving and sending packets, including the method used to acknowledge successful or unsuccessful reception of a packet.
21.2.1
Packet Format
All packets sent and received from the device use the following byte-packed format.
struct { unsigned char ucSize; unsigned char ucCheckSum; unsigned char Data[]; };
ucSize - The first byte received holds the total size of the transfer including the size and checksum bytes. ucChecksum - This holds a simple checksum of the bytes in the data buffer only. The algorithm is Data[0]+Data[1]+...+ Data[ucSize-3]. Data - This is the raw data intended for the device, which is formatted in some form of command interface. There should be ucSize - 2 bytes of data provided in this buffer to or from the device.
21.2.2
Sending Packets
The actual bytes of the packet can be sent individually or all at once, the only limitation is that commands that cause flash memory access should limit the download sizes to prevent losing bytes during flash programming. This limitation is discussed further in the commands that interact with the flash. Once the packet has been formatted correctly by the host, it should be sent out over the UART or SSI interface. Then the host should poll the UART or SSI interface for the first non-zero data returned from the device. The first non-zero byte will either be an ACK (0xCC) or a NAK (0x33) byte from the device indicating the packet was received successfully (ACK) or unsuccessfully (NAK). This does not indicate that the actual contents of the command issued in the data portion of the packet were valid, just that the packet was received correctly.
21.2.3
Receiving Packets
The flash loader sends a packet of data in the same format that it receives a packet. The flash loader may transfer leading zero data before the first actual byte of data is sent out. The first non-zero byte is the size of the packet followed by a checksum byte, and finally followed by the data itself. There is no break in the data after the first non-zero byte is sent from the flash loader. Once the device communicating with the flash loader receives all the bytes, it must either ACK or NAK the packet to indicate that the transmission was successful. The appropriate response after sending a NAK to the flash loader is to resend the command that failed and request the data again. If needed, the host may send leading zeros before sending down the ACK/NAK signal to the flash loader, as the flash loader only accepts the first non-zero data as a valid response. This zero padding is needed by the SSI interface in order to receive data to or from the flash loader.
21.3
Commands
The next section defines the list of commands that can be sent to the flash loader. The first byte of the data should always be one of the defined commands, followed by data or parameters as determined by the command that is sent.
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21.3.1
COMMAND_PING (0x20)
This command simply accepts the command and sets the global status to success. The format of the packet is as follows:
Byte[0] = 0x03; Byte[1] = checksum(Byte[2]); Byte[2] = COMMAND_PING;
The ping command has 3 bytes and the value for COMMAND_PING is 0x20 and the checksum of one byte is that same byte, making Byte[1] also 0x20. Since the ping command has no real return status, the receipt of an ACK can be interpreted as a successful ping to the flash loader.
21.3.2
COMMAND_GET_STATUS (0x23)
This command returns the status of the last command that was issued. Typically, this command should be sent after every command to ensure that the previous command was successful or to properly respond to a failure. The command requires one byte in the data of the packet and should be followed by reading a packet with one byte of data that contains a status code. The last step is to ACK or NAK the received data so the flash loader knows that the data has been read.
Byte[0] = 0x03 Byte[1] = checksum(Byte[2]) Byte[2] = COMMAND_GET_STATUS
21.3.3
COMMAND_DOWNLOAD (0x21)
This command is sent to the flash loader to indicate where to store data and how many bytes will be sent by the COMMAND_SEND_DATA commands that follow. The command consists of two 32-bit values that are both transferred MSB first. The first 32-bit value is the address to start programming data into, while the second is the 32-bit size of the data that will be sent. This command also triggers an erase of the full area to be programmed so this command takes longer than other commands. This results in a longer time to receive the ACK/NAK back from the board. This command should be followed by a COMMAND_GET_STATUS to ensure that the Program Address and Program size are valid for the device running the flash loader. The format of the packet to send this command is a follows:
Byte[0] = 11 Byte[1] = checksum(Bytes[2:10]) Byte[2] = COMMAND_DOWNLOAD Byte[3] = Program Address [31:24] Byte[4] = Program Address [23:16] Byte[5] = Program Address [15:8] Byte[6] = Program Address [7:0] Byte[7] = Program Size [31:24] Byte[8] = Program Size [23:16] Byte[9] = Program Size [15:8] Byte[10] = Program Size [7:0]
21.3.4
COMMAND_SEND_DATA (0x24)
This command should only follow a COMMAND_DOWNLOAD command or another COMMAND_SEND_DATA command if more data is needed. Consecutive send data commands
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automatically increment address and continue programming from the previous location. The caller should limit transfers of data to a maximum 8 bytes of packet data to allow the flash to program successfully and not overflow input buffers of the serial interfaces. The command terminates programming once the number of bytes indicated by the COMMAND_DOWNLOAD command has been received. Each time this function is called it should be followed by a COMMAND_GET_STATUS to ensure that the data was successfully programmed into the flash. If the flash loader sends a NAK to this command, the flash loader does not increment the current address to allow retransmission of the previous data.
Byte[0] = 11 Byte[1] = checksum(Bytes[2:10]) Byte[2] = COMMAND_SEND_DATA Byte[3] = Data[0] Byte[4] = Data[1] Byte[5] = Data[2] Byte[6] = Data[3] Byte[7] = Data[4] Byte[8] = Data[5] Byte[9] = Data[6] Byte[10] = Data[7]
21.3.5
COMMAND_RUN (0x22)
This command is used to tell the flash loader to execute from the address passed as the parameter in this command. This command consists of a single 32-bit value that is interpreted as the address to execute. The 32-bit value is transmitted MSB first and the flash loader responds with an ACK signal back to the host device before actually executing the code at the given address. This allows the host to know that the command was received successfully and the code is now running.
Byte[0] Byte[1] Byte[2] Byte[3] Byte[4] Byte[5] Byte[6]
= = = = = = =
7 checksum(Bytes[2:6]) COMMAND_RUN Execute Address[31:24] Execute Address[23:16] Execute Address[15:8] Execute Address[7:0]
21.3.6
COMMAND_RESET (0x25)
This command is used to tell the flash loader device to reset. This is useful when downloading a new image that overwrote the flash loader and wants to start from a full reset. Unlike the COMMAND_RUN command, this allows the initial stack pointer to be read by the hardware and set up for the new code. It can also be used to reset the flash loader if a critical error occurs and the host device wants to restart communication with the flash loader.
Byte[0] = 3 Byte[1] = checksum(Byte[2]) Byte[2] = COMMAND_RESET
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The flash loader responds with an ACK signal back to the host device before actually executing the software reset to the device running the flash loader. This allows the host to know that the command was received successfully and the part will be reset.
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Ordering and Contact Information
Ordering Information
Features
c
GPIOsa
Samples Per Second
PWM Pins
# of 10-Bit Channels
LM3S317-IQN25 LM3S317-IQN25(T)f 16 4
3 to 30
3
250K
6
1
-
1
6
CCP Pins
6
QEI
SSI
I2C
Order Number
-
I
QN
a. Minimum is number of pins dedicated to GPIO; additional pins are available if certain peripherals are not used. See data sheet for details. b. One timer available as RTC. c. PWM motion control functionality can be achieved through dedicated motion control hardware (using the PWM pins) or through the motion control features of the general-purpose timers (using the CCP pins). See data sheet for details. d. I=Industrial (-40 to 85C). e. QN=48-pin RoHS-compliant LQFP. f. T=Tape and Reel.
Development Kit
The Luminary Micro Stellaris(R) Family Development Kit provides the hardware and software tools that engineers need to begin development quickly. Ask your Luminary Micro distributor for part number DK-LM3S817. See the Luminary Micro website for the latest tools available.
Tools to begin development quickly
Company Information
Founded in 2004, Luminary Micro, Inc. designs, markets, and sells ARM Cortex-M3-based microcontrollers (MCUs). Austin, Texas-based Luminary Micro is the lead partner for the Cortex-M3 processor, delivering the world's first silicon implementation of the Cortex-M3 processor. Luminary Micro's introduction of the Stellaris(R) family of products provides 32-bit performance for the same price as current 8- and 16-bit microcontroller designs. With entry-level pricing at $1.00 for an ARM technology-based MCU, Luminary Micro's Stellaris product line allows for standardization that eliminates future architectural upgrades or software tool changes. Luminary Micro, Inc. 108 Wild Basin, Suite 350 Austin, TX 78746 Main: +1-512-279-8800 Fax: +1-512-279-8879 http://www.luminarymicro.com
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Speed (Clock Frequency in MHz)
25
ADC Analog Comparator(s) SRAM (KB) Flash (KB) UART(s) Timersb
PWM Operating Temperatured Packagee
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LM3S317 Data Sheet
Support Information
For support on Luminary Micro products, contact: support@luminarymicro.com +1-512-279-8800, ext. 3
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