ETC LM3S1911-IQC50-B0T

P R E L IMI NARY
LM3S1911 Microcontroller
D ATA SH E E T
D S -LM3 S 1 911 - 1 7 2 8
Copyr i ght © 2007 Lum i nar y M i c ro, Inc.
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http://www.luminarymicro.com
2
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Table of Contents
About This Document .................................................................................................................... 17
Audience ..............................................................................................................................................
About This Manual ................................................................................................................................
Related Documents ...............................................................................................................................
Documentation Conventions ..................................................................................................................
17
17
17
17
1
Architectural Overview ...................................................................................................... 19
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
Product Features ......................................................................................................................
Target Applications ....................................................................................................................
High-Level Block Diagram .........................................................................................................
Functional Overview ..................................................................................................................
ARM Cortex™-M3 .....................................................................................................................
Motor Control Peripherals ..........................................................................................................
Analog Peripherals ....................................................................................................................
Serial Communications Peripherals ............................................................................................
System Peripherals ...................................................................................................................
Memory Peripherals ..................................................................................................................
Additional Features ...................................................................................................................
Hardware Details ......................................................................................................................
2
ARM Cortex-M3 Processor Core ...................................................................................... 32
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
Block Diagram ..........................................................................................................................
Functional Description ...............................................................................................................
Serial Wire and JTAG Debug .....................................................................................................
Embedded Trace Macrocell (ETM) .............................................................................................
Trace Port Interface Unit (TPIU) .................................................................................................
ROM Table ...............................................................................................................................
Memory Protection Unit (MPU) ...................................................................................................
Nested Vectored Interrupt Controller (NVIC) ................................................................................
3
Memory Map ....................................................................................................................... 38
4
Interrupts ............................................................................................................................ 40
5
JTAG Interface .................................................................................................................... 42
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
Block Diagram ..........................................................................................................................
Functional Description ...............................................................................................................
JTAG Interface Pins ..................................................................................................................
JTAG TAP Controller .................................................................................................................
Shift Registers ..........................................................................................................................
Operational Considerations ........................................................................................................
Initialization and Configuration ...................................................................................................
Register Descriptions ................................................................................................................
Instruction Register (IR) .............................................................................................................
Data Registers ..........................................................................................................................
6
System Control ................................................................................................................... 53
6.1
6.1.1
6.1.2
Functional Description ............................................................................................................... 53
Device Identification .................................................................................................................. 53
Reset Control ............................................................................................................................ 53
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19
23
24
25
26
26
27
27
28
29
30
30
33
33
33
34
34
34
34
34
43
43
44
45
46
46
49
49
49
51
3
Preliminary
Table of Contents
6.1.3
6.1.4
6.1.5
6.2
6.3
6.4
Power Control ...........................................................................................................................
Clock Control ............................................................................................................................
System Control .........................................................................................................................
Initialization and Configuration ...................................................................................................
Register Map ............................................................................................................................
Register Descriptions ................................................................................................................
7
Hibernation Module .......................................................................................................... 110
7.1
7.2
7.2.1
7.2.2
7.2.3
7.2.4
7.2.5
7.2.6
7.2.7
7.3
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
7.4
7.5
Block Diagram ........................................................................................................................
Functional Description .............................................................................................................
Register Access Timing ...........................................................................................................
Clock Source ..........................................................................................................................
Battery Management ...............................................................................................................
Real-Time Clock ......................................................................................................................
Non-Volatile Memory ...............................................................................................................
Power Control .........................................................................................................................
Interrupts and Status ...............................................................................................................
Initialization and Configuration .................................................................................................
Initialization .............................................................................................................................
RTC Match Functionality (No Hibernation) ................................................................................
RTC Match/Wake-Up from Hibernation .....................................................................................
External Wake-Up from Hibernation ..........................................................................................
RTC/External Wake-Up from Hibernation ..................................................................................
Register Map ..........................................................................................................................
Register Descriptions ..............................................................................................................
8
Internal Memory ............................................................................................................... 129
8.1
8.2
8.2.1
8.2.2
8.3
8.3.1
8.3.2
8.4
8.5
8.6
Block Diagram ........................................................................................................................ 129
Functional Description ............................................................................................................. 129
SRAM Memory ........................................................................................................................ 129
Flash Memory ......................................................................................................................... 130
Flash Memory Initialization and Configuration ........................................................................... 131
Flash Programming ................................................................................................................. 131
Nonvolatile Register Programming ........................................................................................... 132
Register Map .......................................................................................................................... 132
Flash Register Descriptions (Flash Control Offset) ..................................................................... 133
Flash Register Descriptions (System Control Offset) .................................................................. 140
9
General-Purpose Input/Outputs (GPIOs) ....................................................................... 153
9.1
9.1.1
9.1.2
9.1.3
9.1.4
9.1.5
9.1.6
9.2
9.3
9.4
Functional Description ............................................................................................................. 153
Data Control ........................................................................................................................... 153
Interrupt Control ...................................................................................................................... 154
Mode Control .......................................................................................................................... 155
Commit Control ....................................................................................................................... 155
Pad Control ............................................................................................................................. 155
Identification ........................................................................................................................... 155
Initialization and Configuration ................................................................................................. 155
Register Map .......................................................................................................................... 157
Register Descriptions .............................................................................................................. 158
4
56
56
58
59
59
60
111
111
111
112
112
112
113
113
113
114
114
114
114
115
115
115
116
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Preliminary
LM3S1911 Microcontroller
10
General-Purpose Timers ................................................................................................. 193
10.1
10.2
10.2.1
10.2.2
10.2.3
10.3
10.3.1
10.3.2
10.3.3
10.3.4
10.3.5
10.3.6
10.4
10.5
Block Diagram ........................................................................................................................
Functional Description .............................................................................................................
GPTM Reset Conditions ..........................................................................................................
32-Bit Timer Operating Modes ..................................................................................................
16-Bit Timer Operating Modes ..................................................................................................
Initialization and Configuration .................................................................................................
32-Bit One-Shot/Periodic Timer Mode .......................................................................................
32-Bit Real-Time Clock (RTC) Mode .........................................................................................
16-Bit One-Shot/Periodic Timer Mode .......................................................................................
16-Bit Input Edge Count Mode .................................................................................................
16-Bit Input Edge Timing Mode ................................................................................................
16-Bit PWM Mode ...................................................................................................................
Register Map ..........................................................................................................................
Register Descriptions ..............................................................................................................
11
Watchdog Timer ............................................................................................................... 229
11.1
11.2
11.3
11.4
11.5
Block Diagram ........................................................................................................................
Functional Description .............................................................................................................
Initialization and Configuration .................................................................................................
Register Map ..........................................................................................................................
Register Descriptions ..............................................................................................................
12
Universal Asynchronous Receivers/Transmitters (UARTs) ......................................... 252
12.1
12.2
12.2.1
12.2.2
12.2.3
12.2.4
12.2.5
12.2.6
12.2.7
12.2.8
12.3
12.4
12.5
Block Diagram ........................................................................................................................
Functional Description .............................................................................................................
Transmit/Receive Logic ...........................................................................................................
Baud-Rate Generation .............................................................................................................
Data Transmission ..................................................................................................................
Serial IR (SIR) .........................................................................................................................
FIFO Operation .......................................................................................................................
Interrupts ................................................................................................................................
Loopback Operation ................................................................................................................
IrDA SIR block ........................................................................................................................
Initialization and Configuration .................................................................................................
Register Map ..........................................................................................................................
Register Descriptions ..............................................................................................................
13
Synchronous Serial Interface (SSI) ................................................................................ 293
13.1
13.2
13.2.1
13.2.2
13.2.3
13.2.4
13.3
13.4
13.5
Block Diagram ........................................................................................................................
Functional Description .............................................................................................................
Bit Rate Generation .................................................................................................................
FIFO Operation .......................................................................................................................
Interrupts ................................................................................................................................
Frame Formats .......................................................................................................................
Initialization and Configuration .................................................................................................
Register Map ..........................................................................................................................
Register Descriptions ..............................................................................................................
14
Inter-Integrated Circuit (I2C) Interface ............................................................................ 330
14.1
Block Diagram ........................................................................................................................ 330
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194
194
194
194
196
200
200
201
201
202
202
203
203
204
229
229
230
230
231
253
253
253
254
255
255
256
256
257
257
257
258
259
293
293
294
294
294
295
302
303
304
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Preliminary
Table of Contents
14.2
14.2.1
14.2.2
14.2.3
14.2.4
14.2.5
14.3
14.4
14.5
14.6
Functional Description .............................................................................................................
I2C Bus Functional Overview ....................................................................................................
Available Speed Modes ...........................................................................................................
Interrupts ................................................................................................................................
Loopback Operation ................................................................................................................
Command Sequence Flow Charts ............................................................................................
Initialization and Configuration .................................................................................................
I2C Register Map .....................................................................................................................
Register Descriptions (I2C Master) ...........................................................................................
Register Descriptions (I2C Slave) .............................................................................................
15
Analog Comparators ....................................................................................................... 365
15.1
15.2
15.2.1
15.3
15.4
15.5
Block Diagram ........................................................................................................................
Functional Description .............................................................................................................
Internal Reference Programming ..............................................................................................
Initialization and Configuration .................................................................................................
Register Map ..........................................................................................................................
Register Descriptions ..............................................................................................................
16
Pin Diagram ...................................................................................................................... 377
17
Signal Tables .................................................................................................................... 378
18
Operating Characteristics ............................................................................................... 392
19
Electrical Characteristics ................................................................................................ 393
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
19.2.9
DC Characteristics .................................................................................................................. 393
Maximum Ratings ................................................................................................................... 393
Recommended DC Operating Conditions .................................................................................. 393
On-Chip Low Drop-Out (LDO) Regulator Characteristics ............................................................ 394
Power Specifications ............................................................................................................... 394
Flash Memory Characteristics .................................................................................................. 396
AC Characteristics ................................................................................................................... 396
Load Conditions ...................................................................................................................... 396
Clocks .................................................................................................................................... 396
Analog Comparator ................................................................................................................. 397
I2C ......................................................................................................................................... 397
Hibernation Module ................................................................................................................. 398
Synchronous Serial Interface (SSI) ........................................................................................... 399
JTAG and Boundary Scan ........................................................................................................ 400
General-Purpose I/O ............................................................................................................... 402
Reset ..................................................................................................................................... 402
20
Package Information ........................................................................................................ 405
A
Serial Flash Loader .......................................................................................................... 407
A.1
A.2
A.2.1
A.2.2
A.3
A.3.1
A.3.2
Serial Flash Loader .................................................................................................................
Interfaces ...............................................................................................................................
UART .....................................................................................................................................
SSI .........................................................................................................................................
Packet Handling ......................................................................................................................
Packet Format ........................................................................................................................
Sending Packets .....................................................................................................................
6
330
331
333
334
334
335
341
342
343
356
365
365
367
368
368
369
407
407
407
407
408
408
408
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Preliminary
LM3S1911 Microcontroller
A.3.3
A.4
A.4.1
A.4.2
A.4.3
A.4.4
A.4.5
A.4.6
Receiving Packets ...................................................................................................................
Commands .............................................................................................................................
COMMAND_PING (0X20) ........................................................................................................
COMMAND_GET_STATUS (0x23) ...........................................................................................
COMMAND_DOWNLOAD (0x21) .............................................................................................
COMMAND_SEND_DATA (0x24) .............................................................................................
COMMAND_RUN (0x22) .........................................................................................................
COMMAND_RESET (0x25) .....................................................................................................
B
Register Quick Reference ............................................................................................... 412
C
Ordering and Contact Information ................................................................................. 425
C.1
C.2
C.3
C.4
Ordering Information ................................................................................................................
Kits .........................................................................................................................................
Company Information ..............................................................................................................
Support Information .................................................................................................................
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408
409
409
409
409
410
410
410
425
425
425
426
7
Preliminary
Table of Contents
List of Figures
Figure 1-1.
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 7-1.
Figure 8-1.
Figure 9-1.
Figure 9-2.
Figure 10-1.
Figure 10-2.
Figure 10-3.
Figure 10-4.
Figure 11-1.
Figure 12-1.
Figure 12-2.
Figure 12-3.
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 14-4.
Figure 14-5.
Figure 14-6.
Figure 14-7.
Figure 14-8.
Figure 14-9.
Figure 14-10.
Figure 14-11.
Figure 14-12.
®
Stellaris 1000 Series High-Level Block Diagram ............................................................... 25
CPU Block Diagram ......................................................................................................... 33
TPIU Block Diagram ........................................................................................................ 34
JTAG Module Block Diagram ............................................................................................ 43
Test Access Port State Machine ....................................................................................... 46
IDCODE Register Format ................................................................................................. 51
BYPASS Register Format ................................................................................................ 52
Boundary Scan Register Format ....................................................................................... 52
External Circuitry to Extend Reset .................................................................................... 54
Hibernation Module Block Diagram ................................................................................. 111
Flash Block Diagram ...................................................................................................... 129
GPIODATA Write Example ............................................................................................. 154
GPIODATA Read Example ............................................................................................. 154
GPTM Module Block Diagram ........................................................................................ 194
16-Bit Input Edge Count Mode Example .......................................................................... 198
16-Bit Input Edge Time Mode Example ........................................................................... 199
16-Bit PWM Mode Example ............................................................................................ 200
WDT Module Block Diagram .......................................................................................... 229
UART Module Block Diagram ......................................................................................... 253
UART Character Frame ................................................................................................. 254
IrDA Data Modulation ..................................................................................................... 256
SSI Module Block Diagram ............................................................................................. 293
TI Synchronous Serial Frame Format (Single Transfer) .................................................... 295
TI Synchronous Serial Frame Format (Continuous Transfer) ............................................ 296
Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 ...................................... 297
Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 .............................. 297
Freescale SPI Frame Format with SPO=0 and SPH=1 ..................................................... 298
Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0 ........................... 299
Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0 .................... 299
Freescale SPI Frame Format with SPO=1 and SPH=1 ..................................................... 300
MICROWIRE Frame Format (Single Frame) .................................................................... 301
MICROWIRE Frame Format (Continuous Transfer) ......................................................... 302
MICROWIRE Frame Format, SSIFss Input Setup and Hold Requirements ........................ 302
I2C Block Diagram ......................................................................................................... 330
I2C Bus Configuration .................................................................................................... 331
START and STOP Conditions ......................................................................................... 331
Complete Data Transfer with a 7-Bit Address ................................................................... 332
R/S Bit in First Byte ........................................................................................................ 332
Data Validity During Bit Transfer on the I2C Bus ............................................................... 332
Master Single SEND ...................................................................................................... 335
Master Single RECEIVE ................................................................................................. 336
Master Burst SEND ....................................................................................................... 337
Master Burst RECEIVE .................................................................................................. 338
Master Burst RECEIVE after Burst SEND ........................................................................ 339
Master Burst SEND after Burst RECEIVE ........................................................................ 340
8
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Figure 14-13.
Figure 15-1.
Figure 15-2.
Figure 15-3.
Figure 16-1.
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 19-14.
Figure 20-1.
Slave Command Sequence ............................................................................................ 341
Analog Comparator Module Block Diagram ..................................................................... 365
Structure of Comparator Unit .......................................................................................... 366
Comparator Internal Reference Structure ........................................................................ 367
Pin Connection Diagram ................................................................................................ 377
Load Conditions ............................................................................................................ 396
I2C Timing ..................................................................................................................... 398
Hibernation Module Timing ............................................................................................. 399
SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement .............. 399
SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer ............................. 400
SSI Timing for SPI Frame Format (FRF=00), with SPH=1 ................................................. 400
JTAG Test Clock Input Timing ......................................................................................... 401
JTAG Test Access Port (TAP) Timing .............................................................................. 402
JTAG TRST Timing ........................................................................................................ 402
External Reset Timing (RST) .......................................................................................... 403
Power-On Reset Timing ................................................................................................. 403
Brown-Out Reset Timing ................................................................................................ 403
Software Reset Timing ................................................................................................... 404
Watchdog Reset Timing ................................................................................................. 404
100-Pin LQFP Package .................................................................................................. 405
October 09, 2007
9
Preliminary
Table of Contents
List of Tables
Table 1.
Table 3-1.
Table 4-1.
Table 4-2.
Table 5-1.
Table 5-2.
Table 6-1.
Table 7-1.
Table 8-1.
Table 8-2.
Table 8-3.
Table 9-1.
Table 9-2.
Table 9-3.
Table 10-1.
Table 10-2.
Table 11-1.
Table 12-1.
Table 13-1.
Table 14-1.
Table 14-2.
Table 14-3.
Table 15-1.
Table 15-2.
Table 15-3.
Table 15-4.
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 ................................................................................................................... 38
Exception Types .............................................................................................................. 40
Interrupts ........................................................................................................................ 41
JTAG Port Pins Reset State ............................................................................................. 44
JTAG Instruction Register Commands ............................................................................... 49
System Control Register Map ........................................................................................... 59
Hibernation Module Register Map ................................................................................... 115
Flash Protection Policy Combinations ............................................................................. 131
Flash Resident Registers ............................................................................................... 132
Flash Register Map ........................................................................................................ 132
GPIO Pad Configuration Examples ................................................................................. 156
GPIO Interrupt Configuration Example ............................................................................ 156
GPIO Register Map ....................................................................................................... 157
16-Bit Timer With Prescaler Configurations ..................................................................... 197
Timers Register Map ...................................................................................................... 203
Watchdog Timer Register Map ........................................................................................ 230
UART Register Map ....................................................................................................... 258
SSI Register Map .......................................................................................................... 304
Examples of I2C Master Timer Period versus Speed Mode ............................................... 333
Inter-Integrated Circuit (I2C) Interface Register Map ......................................................... 342
Write Field Decoding for I2CMCS[3:0] Field (Sheet 1 of 3) ................................................ 347
Comparator 0 Operating Modes ..................................................................................... 366
Comparator 1 Operating Modes ...................................................................................... 367
Internal Reference Voltage and ACREFCTL Field Values ................................................. 367
Analog Comparators Register Map ................................................................................. 369
Signals by Pin Number ................................................................................................... 378
Signals by Signal Name ................................................................................................. 382
Signals by Function, Except for GPIO ............................................................................. 386
GPIO Pins and Alternate Functions ................................................................................. 390
Temperature Characteristics ........................................................................................... 392
Thermal Characteristics ................................................................................................. 392
Maximum Ratings .......................................................................................................... 393
Recommended DC Operating Conditions ........................................................................ 393
LDO Regulator Characteristics ....................................................................................... 394
Detailed Power Specifications ........................................................................................ 395
Flash Memory Characteristics ........................................................................................ 396
Phase Locked Loop (PLL) Characteristics ....................................................................... 396
Clock Characteristics ..................................................................................................... 396
Crystal Characteristics ................................................................................................... 397
Analog Comparator Characteristics ................................................................................. 397
Analog Comparator Voltage Reference Characteristics .................................................... 397
I2C Characteristics ......................................................................................................... 397
Hibernation Module Characteristics ................................................................................. 398
SSI Characteristics ........................................................................................................ 399
JTAG Characteristics ..................................................................................................... 400
10
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Table 19-15. GPIO Characteristics ..................................................................................................... 402
Table 19-16. Reset Characteristics ..................................................................................................... 402
Table C-1.
Part Ordering Information ............................................................................................... 425
October 09, 2007
11
Preliminary
Table of Contents
List of Registers
System Control .............................................................................................................................. 53
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:
Device Identification 0 (DID0), offset 0x000 ....................................................................... 61
Brown-Out Reset Control (PBORCTL), offset 0x030 .......................................................... 63
LDO Power Control (LDOPCTL), offset 0x034 ................................................................... 64
Raw Interrupt Status (RIS), offset 0x050 ........................................................................... 65
Interrupt Mask Control (IMC), offset 0x054 ........................................................................ 66
Masked Interrupt Status and Clear (MISC), offset 0x058 .................................................... 67
Reset Cause (RESC), offset 0x05C .................................................................................. 68
Run-Mode Clock Configuration (RCC), offset 0x060 .......................................................... 69
XTAL to PLL Translation (PLLCFG), offset 0x064 .............................................................. 73
Run-Mode Clock Configuration 2 (RCC2), offset 0x070 ...................................................... 74
Deep Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 .......................................... 76
Device Identification 1 (DID1), offset 0x004 ....................................................................... 77
Device Capabilities 0 (DC0), offset 0x008 ......................................................................... 79
Device Capabilities 1 (DC1), offset 0x010 ......................................................................... 80
Device Capabilities 2 (DC2), offset 0x014 ......................................................................... 82
Device Capabilities 3 (DC3), offset 0x018 ......................................................................... 84
Device Capabilities 4 (DC4), offset 0x01C ......................................................................... 86
Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100 .................................... 88
Sleep Mode Clock Gating Control Register 0 (SCGC0), offset 0x110 .................................. 89
Deep Sleep Mode Clock Gating Control Register 0 (DCGC0), offset 0x120 ......................... 90
Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104 .................................... 91
Sleep Mode Clock Gating Control Register 1 (SCGC1), offset 0x114 .................................. 94
Deep Sleep Mode Clock Gating Control Register 1 (DCGC1), offset 0x124 ......................... 97
Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108 ................................... 100
Sleep Mode Clock Gating Control Register 2 (SCGC2), offset 0x118 ................................. 102
Deep Sleep Mode Clock Gating Control Register 2 (DCGC2), offset 0x128 ....................... 104
Software Reset Control 0 (SRCR0), offset 0x040 ............................................................. 106
Software Reset Control 1 (SRCR1), offset 0x044 ............................................................. 107
Software Reset Control 2 (SRCR2), offset 0x048 ............................................................. 109
Hibernation Module ..................................................................................................................... 110
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
Hibernation RTC Counter (HIBRTCC), offset 0x000 .........................................................
Hibernation RTC Match 0 (HIBRTCM0), offset 0x004 .......................................................
Hibernation RTC Match 1 (HIBRTCM1), offset 0x008 .......................................................
Hibernation RTC Load (HIBRTCLD), offset 0x00C ...........................................................
Hibernation Control (HIBCTL), offset 0x010 .....................................................................
Hibernation Interrupt Mask (HIBIM), offset 0x014 .............................................................
Hibernation Raw Interrupt Status (HIBRIS), offset 0x018 ..................................................
Hibernation Masked Interrupt Status (HIBMIS), offset 0x01C ............................................
Hibernation Interrupt Clear (HIBIC), offset 0x020 .............................................................
Hibernation RTC Trim (HIBRTCT), offset 0x024 ...............................................................
Hibernation Data (HIBDATA), offset 0x030-0x12C ............................................................
117
118
119
120
121
123
124
125
126
127
128
Internal Memory ........................................................................................................................... 129
Register 1:
Register 2:
Flash Memory Address (FMA), offset 0x000 .................................................................... 134
Flash Memory Data (FMD), offset 0x004 ......................................................................... 135
12
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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:
Flash Memory Control (FMC), offset 0x008 .....................................................................
Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C ............................................
Flash Controller Interrupt Mask (FCIM), offset 0x010 ........................................................
Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014 .....................
USec Reload (USECRL), offset 0x140 ............................................................................
Flash Memory Protection Read Enable 0 (FMPRE0), offset 0x130 and 0x200 ...................
Flash Memory Protection Program Enable 0 (FMPPE0), offset 0x134 and 0x400 ...............
User Debug (USER_DBG), offset 0x1D0 .........................................................................
User Register 0 (USER_REG0), offset 0x1E0 ..................................................................
User Register 1 (USER_REG1), offset 0x1E4 ..................................................................
Flash Memory Protection Read Enable 1 (FMPRE1), offset 0x204 ....................................
Flash Memory Protection Read Enable 2 (FMPRE2), offset 0x208 ....................................
Flash Memory Protection Read Enable 3 (FMPRE3), offset 0x20C ...................................
Flash Memory Protection Program Enable 1 (FMPPE1), offset 0x404 ...............................
Flash Memory Protection Program Enable 2 (FMPPE2), offset 0x408 ...............................
Flash Memory Protection Program Enable 3 (FMPPE3), offset 0x40C ...............................
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
General-Purpose Input/Outputs (GPIOs) ................................................................................... 153
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 31:
GPIO Data (GPIODATA), offset 0x000 ............................................................................ 159
GPIO Direction (GPIODIR), offset 0x400 ......................................................................... 160
GPIO Interrupt Sense (GPIOIS), offset 0x404 .................................................................. 161
GPIO Interrupt Both Edges (GPIOIBE), offset 0x408 ........................................................ 162
GPIO Interrupt Event (GPIOIEV), offset 0x40C ................................................................ 163
GPIO Interrupt Mask (GPIOIM), offset 0x410 ................................................................... 164
GPIO Raw Interrupt Status (GPIORIS), offset 0x414 ........................................................ 165
GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 ................................................... 166
GPIO Interrupt Clear (GPIOICR), offset 0x41C ................................................................ 167
GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 ............................................ 168
GPIO 2-mA Drive Select (GPIODR2R), offset 0x500 ........................................................ 170
GPIO 4-mA Drive Select (GPIODR4R), offset 0x504 ........................................................ 171
GPIO 8-mA Drive Select (GPIODR8R), offset 0x508 ........................................................ 172
GPIO Open Drain Select (GPIOODR), offset 0x50C ......................................................... 173
GPIO Pull-Up Select (GPIOPUR), offset 0x510 ................................................................ 174
GPIO Pull-Down Select (GPIOPDR), offset 0x514 ........................................................... 175
GPIO Slew Rate Control Select (GPIOSLR), offset 0x518 ................................................ 176
GPIO Digital Enable (GPIODEN), offset 0x51C ................................................................ 177
GPIO Lock (GPIOLOCK), offset 0x520 ............................................................................ 178
GPIO Commit (GPIOCR), offset 0x524 ............................................................................ 179
GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 ....................................... 181
GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 ....................................... 182
GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 ....................................... 183
GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC ...................................... 184
GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 ....................................... 185
GPIO Peripheral Identification 1 (GPIOPeriphID1), offset 0xFE4 ....................................... 186
GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 ....................................... 187
GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC ...................................... 188
GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 .......................................... 189
GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 .......................................... 190
GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 .......................................... 191
October 09, 2007
13
Preliminary
Table of Contents
Register 32:
GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC ......................................... 192
General-Purpose Timers ............................................................................................................. 193
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:
GPTM Configuration (GPTMCFG), offset 0x000 ..............................................................
GPTM TimerA Mode (GPTMTAMR), offset 0x004 ............................................................
GPTM TimerB Mode (GPTMTBMR), offset 0x008 ............................................................
GPTM Control (GPTMCTL), offset 0x00C ........................................................................
GPTM Interrupt Mask (GPTMIMR), offset 0x018 ..............................................................
GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C .....................................................
GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 ................................................
GPTM Interrupt Clear (GPTMICR), offset 0x024 ..............................................................
GPTM TimerA Interval Load (GPTMTAILR), offset 0x028 .................................................
GPTM TimerB Interval Load (GPTMTBILR), offset 0x02C ................................................
GPTM TimerA Match (GPTMTAMATCHR), offset 0x030 ...................................................
GPTM TimerB Match (GPTMTBMATCHR), offset 0x034 ..................................................
GPTM TimerA Prescale (GPTMTAPR), offset 0x038 ........................................................
GPTM TimerB Prescale (GPTMTBPR), offset 0x03C .......................................................
GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040 ...........................................
GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044 ...........................................
GPTM TimerA (GPTMTAR), offset 0x048 ........................................................................
GPTM TimerB (GPTMTBR), offset 0x04C .......................................................................
205
206
208
210
213
215
216
217
219
220
221
222
223
224
225
226
227
228
Watchdog Timer ........................................................................................................................... 229
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:
Watchdog Load (WDTLOAD), offset 0x000 ......................................................................
Watchdog Value (WDTVALUE), offset 0x004 ...................................................................
Watchdog Control (WDTCTL), offset 0x008 .....................................................................
Watchdog Interrupt Clear (WDTICR), offset 0x00C ..........................................................
Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 ..................................................
Watchdog Masked Interrupt Status (WDTMIS), offset 0x014 .............................................
Watchdog Test (WDTTEST), offset 0x418 .......................................................................
Watchdog Lock (WDTLOCK), offset 0xC00 .....................................................................
Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0 .................................
Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4 .................................
Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8 .................................
Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC ................................
Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 .................................
Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 .................................
Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 .................................
Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC .................................
Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0 ....................................
Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4 ....................................
Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8 ....................................
Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC ..................................
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
Universal Asynchronous Receivers/Transmitters (UARTs) ..................................................... 252
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
UART Data (UARTDR), offset 0x000 ...............................................................................
UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 ...........................
UART Flag (UARTFR), offset 0x018 ................................................................................
UART IrDA Low-Power Register (UARTILPR), offset 0x020 .............................................
UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 ............................................
UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 .......................................
14
260
262
264
266
267
268
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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:
UART Line Control (UARTLCRH), offset 0x02C ...............................................................
UART Control (UARTCTL), offset 0x030 .........................................................................
UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 ...........................................
UART Interrupt Mask (UARTIM), offset 0x038 .................................................................
UART Raw Interrupt Status (UARTRIS), offset 0x03C ......................................................
UART Masked Interrupt Status (UARTMIS), offset 0x040 .................................................
UART Interrupt Clear (UARTICR), offset 0x044 ...............................................................
UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 .....................................
UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 .....................................
UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 .....................................
UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC .....................................
UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 ......................................
UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 ......................................
UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 ......................................
UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC .....................................
UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 ........................................
UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 ........................................
UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 ........................................
UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC ........................................
269
271
273
275
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
Synchronous Serial Interface (SSI) ............................................................................................ 293
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:
SSI Control 0 (SSICR0), offset 0x000 ..............................................................................
SSI Control 1 (SSICR1), offset 0x004 ..............................................................................
SSI Data (SSIDR), offset 0x008 ......................................................................................
SSI Status (SSISR), offset 0x00C ...................................................................................
SSI Clock Prescale (SSICPSR), offset 0x010 ..................................................................
SSI Interrupt Mask (SSIIM), offset 0x014 .........................................................................
SSI Raw Interrupt Status (SSIRIS), offset 0x018 ..............................................................
SSI Masked Interrupt Status (SSIMIS), offset 0x01C ........................................................
SSI Interrupt Clear (SSIICR), offset 0x020 .......................................................................
SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 .............................................
SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 .............................................
SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 .............................................
SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC ............................................
SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0 .............................................
SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4 .............................................
SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8 .............................................
SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC ............................................
SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0 ...............................................
SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4 ...............................................
SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8 ...............................................
SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC ...............................................
305
307
309
310
312
313
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
Inter-Integrated Circuit (I2C) Interface ........................................................................................ 330
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
I2C Master Slave Address (I2CMSA), offset 0x000 ...........................................................
I2C Master Control/Status (I2CMCS), offset 0x004 ...........................................................
I2C Master Data (I2CMDR), offset 0x008 .........................................................................
I2C Master Timer Period (I2CMTPR), offset 0x00C ...........................................................
I2C Master Interrupt Mask (I2CMIMR), offset 0x010 .........................................................
I2C Master Raw Interrupt Status (I2CMRIS), offset 0x014 .................................................
October 09, 2007
344
345
349
350
351
352
15
Preliminary
Table of Contents
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
Register 12:
Register 13:
Register 14:
Register 15:
Register 16:
I2C Master Masked Interrupt Status (I2CMMIS), offset 0x018 ...........................................
I2C Master Interrupt Clear (I2CMICR), offset 0x01C .........................................................
I2C Master Configuration (I2CMCR), offset 0x020 ............................................................
I2C Slave Own Address (I2CSOAR), offset 0x000 ............................................................
I2C Slave Control/Status (I2CSCSR), offset 0x004 ...........................................................
I2C Slave Data (I2CSDR), offset 0x008 ...........................................................................
I2C Slave Interrupt Mask (I2CSIMR), offset 0x00C ...........................................................
I2C Slave Raw Interrupt Status (I2CSRIS), offset 0x010 ...................................................
I2C Slave Masked Interrupt Status (I2CSMIS), offset 0x014 ..............................................
I2C Slave Interrupt Clear (I2CSICR), offset 0x018 ............................................................
353
354
355
357
358
360
361
362
363
364
Analog Comparators ................................................................................................................... 365
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Analog Comparator Masked Interrupt Status (ACMIS), offset 0x00 ....................................
Analog Comparator Raw Interrupt Status (ACRIS), offset 0x04 .........................................
Analog Comparator Interrupt Enable (ACINTEN), offset 0x08 ...........................................
Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x10 .........................
Analog Comparator Status 0 (ACSTAT0), offset 0x20 .......................................................
Analog Comparator Status 1 (ACSTAT1), offset 0x40 .......................................................
Analog Comparator Control 0 (ACCTL0), offset 0x24 .......................................................
Analog Comparator Control 1 (ACCTL1), offset 0x44 .......................................................
16
370
371
372
373
374
374
375
375
October 09, 2007
Preliminary
LM3S1911 Microcontroller
About This Document
This data sheet provides reference information for the LM3S1911 microcontroller, describing the
functional blocks of the system-on-chip (SoC) device designed around the ARM® Cortex™-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® Cortex™-M3 Technical Reference Manual
■ ARM® CoreSight Technical Reference Manual
■ ARM® 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 1 on page 17.
Table 1. Documentation Conventions
Notation
Meaning
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.
bit
A single bit in a register.
bit field
Two or more consecutive and related bits.
offset 0xnnn
A hexadecimal increment to a register's address, relative to that module's base address as specified
in “Memory Map” on page 38.
Register N
Registers are numbered consecutively throughout the document to aid in referencing them. The
register number has no meaning to software.
October 09, 2007
17
Preliminary
About This Document
Notation
Meaning
reserved
Register bits marked reserved are reserved for future use. In most cases, reserved bits are set to
0; however, user software should not rely on the value of a reserved bit. To provide software
compatibility with future products, the value of a reserved bit should be preserved across a
read-modify-write operation.
yy:xx
The range of register bits inclusive from xx to yy. For example, 31:15 means bits 15 through 31 in
that register.
Register Bit/Field
Types
This value in the register bit diagram indicates whether software running on the controller can
change the value of the bit field.
RC
Software can read this field. The bit or field is cleared by hardware after reading the bit/field.
RO
Software can read this field. Always write the chip reset value.
R/W
Software can read or write this field.
R/W1C
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.
Register Bit/Field
Reset Value
This value in the register bit diagram shows the bit/field value after any reset, unless noted.
0
Bit cleared to 0 on chip reset.
1
Bit set to 1 on chip reset.
-
Nondeterministic.
Pin/Signal Notation
[]
Pin alternate function; a pin defaults to the signal without the brackets.
pin
Refers to the physical connection on the package.
signal
Refers to the electrical signal encoding of a pin.
assert a signal
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).
deassert a signal
Change the value of the signal from the logically True state to the logically False state.
SIGNAL
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
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.
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.
0x
Hexadecimal numbers have a prefix of 0x. For example, 0x00FF is the hexadecimal number FF.
All other numbers within register tables are assumed to be binary. Within conceptual information,
binary numbers are indicated with a b suffix, for example, 1011b, and decimal numbers are written
without a prefix or suffix.
18
October 09, 2007
Preliminary
LM3S1911 Microcontroller
1
Architectural Overview
®
The Luminary Micro Stellaris family of microcontrollers—the first ARM® Cortex™-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 Stellaris family offers efficient performance and extensive integration, favorably positioning
the device into cost-conscious applications requiring significant control-processing and connectivity
®
®
capabilities. The Stellaris LM3S1000 series extends the Stellaris family with larger on-chip
®
memories, enhanced power management, and expanded I/O and control capabilities. The Stellaris
LM3S2000 series, designed for Controller Area Network (CAN) applications, extends the Stellaris
family with Bosch CAN networking technology, the golden standard in short-haul industrial networks.
®
The Stellaris LM3S2000 series also marks the first integration of CAN capabilities with the
®
revolutionary Cortex-M3 core. The Stellaris LM3S6000 series combines both a 10/100 Ethernet
Media Access Control (MAC) and Physical (PHY) layer, marking the first time that integrated
connectivity is available with an ARM Cortex-M3 MCU and the only integrated 10/100 Ethernet MAC
®
and PHY available in an ARM architecture MCU. The Stellaris LM3S8000 series combines Bosch
Controller Area Network technology with both a 10/100 Ethernet Media Access Control (MAC) and
Physical (PHY) layer.
The LM3S1911 microcontroller is targeted for industrial applications, including remote monitoring,
electronic point-of-sale machines, test and measurement equipment, network appliances and
switches, factory automation, HVAC and building control, gaming equipment, motion control, medical
instrumentation, and fire and security.
For applications requiring extreme conservation of power, the LM3S1911 microcontroller features
a Battery-backed Hibernation module to efficiently power down the LM3S1911 to a low-power state
during extended periods of inactivity. With a power-up/power-down sequencer, a continuous time
counter (RTC), a pair of match registers, an APB interface to the system bus, and dedicated
non-volatile memory, the Hibernation module positions the LM3S1911 microcontroller perfectly for
battery applications.
In addition, the LM3S1911 microcontroller offers the advantages of ARM's widely available
development tools, System-on-Chip (SoC) infrastructure IP applications, and a large user community.
Additionally, the microcontroller uses ARM's Thumb®-compatible Thumb-2 instruction set to reduce
memory requirements and, thereby, cost. Finally, the LM3S1911 microcontroller is code-compatible
®
to all members of the extensive Stellaris family; providing flexibility to fit our customers' precise
needs.
Luminary Micro offers a complete solution to get to market quickly, with evaluation and development
boards, white papers and application notes, an easy-to-use peripheral driver library, and a strong
support, sales, and distributor network.
1.1
Product Features
The LM3S1911 microcontroller includes the following product features:
■ 32-Bit RISC Performance
– 32-bit ARM® Cortex™-M3 v7M architecture optimized for small-footprint embedded
applications
October 09, 2007
19
Preliminary
Architectural Overview
– System timer (SysTick), providing a simple, 24-bit clear-on-write, decrementing, wrap-on-zero
counter with a flexible control mechanism
– Thumb®-compatible Thumb-2-only instruction set processor core for high code density
– 50-MHz operation
– Hardware-division and single-cycle-multiplication
– Integrated Nested Vectored Interrupt Controller (NVIC) providing deterministic interrupt
handling
– 29 interrupts with eight priority levels
– Memory protection unit (MPU), providing a privileged mode for protected operating system
functionality
– Unaligned data access, enabling data to be efficiently packed into memory
– Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined
peripheral control
■ Internal Memory
– 256 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
– 64 KB single-cycle SRAM
■ General-Purpose Timers
– Four General-Purpose Timer Modules (GPTM), each of which provides two 16-bit
timer/counters. Each GPTM can be configured to operate independently as timers or event
counters as a single 32-bit timer, as one 32-bit Real-Time Clock (RTC) to event capture, or
for Pulse Width Modulation (PWM)
– 32-bit Timer modes
•
Programmable one-shot timer
•
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
– 16-bit Timer modes
•
General-purpose timer function with an 8-bit prescaler
20
October 09, 2007
Preliminary
LM3S1911 Microcontroller
•
Programmable one-shot timer
•
Programmable periodic timer
•
User-enabled stalling when the controller asserts CPU Halt flag during debug
– 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
■ 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)
– Two SSI modules, each with 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
■ UART
– Three fully programmable 16C550-type UARTs with IrDA support
– Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs to reduce CPU interrupt service
loading
– Programmable baud-rate generator with fractional divider
October 09, 2007
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Preliminary
Architectural Overview
– 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
– Standard asynchronous communication bits for start, stop, and parity
– False-start-bit detection
– Line-break generation and detection
■ Analog Comparators
– Two independent integrated analog comparators
– Configurable for output to: drive an output pin or generate an interrupt
– Compare external pin input to external pin input or to internal programmable voltage reference
■ I2C
2
– Two I C modules
– Master and slave receive and transmit operation with transmission speed up to 100 Kbps in
Standard mode and 400 Kbps in Fast mode
– Interrupt generation
– Master with arbitration and clock synchronization, multimaster support, and 7-bit addressing
mode
■ GPIOs
– 23-60 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
– 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
■ Power
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
– On-chip Low Drop-Out (LDO) voltage regulator, with programmable output user-adjustable
from 2.25 V to 2.75 V
– Hibernation module handles the power-up/down 3.3 V sequencing and control for the core
digital logic and analog circuits
– 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 brown-out detection and reporting via interrupt or reset
■ 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
– 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 100-pin RoHS-compliant LQFP package
1.2
Target Applications
■ Remote monitoring
■ Electronic point-of-sale (POS) machines
■ Test and measurement equipment
■ Network appliances and switches
■ Factory automation
October 09, 2007
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Preliminary
Architectural Overview
■ HVAC and building control
■ Gaming equipment
■ Motion control
■ Medical instrumentation
■ Fire and security
■ Power and energy
■ Transportation
1.3
High-Level Block Diagram
®
Figure 1-1 on page 25 represents the full set of features in the Stellaris 1000 series of devices;
not all features may be available on the LM3S1911 microcontroller.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
®
Figure 1-1. Stellaris 1000 Series High-Level Block Diagram
1.4
Functional Overview
The following sections provide an overview of the features of the LM3S1911 microcontroller. The
page 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 425.
October 09, 2007
25
Preliminary
Architectural Overview
1.4.1
ARM Cortex™-M3
1.4.1.1
Processor Core (see page 32)
®
All members of the Stellaris product family, including the LM3S1911 microcontroller, are designed
around an 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.
“ARM Cortex-M3 Processor Core” on page 32 provides an overview of the ARM core; the core is
detailed in the ARM® Cortex™-M3 Technical Reference Manual.
1.4.1.2
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.
1.4.1.3
Nested Vectored Interrupt Controller (NVIC)
The LM3S1911 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 29 interrupts.
“Interrupts” on page 40 provides an overview of the NVIC controller and the interrupt map. Exceptions
and interrupts are detailed in the ARM® Cortex™-M3 Technical Reference Manual.
1.4.2
Motor Control Peripherals
To enhance motor control, the LM3S1911 controller features Pulse Width Modulation (PWM) outputs.
1.4.2.1
PWM (see page 199)
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.
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October 09, 2007
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LM3S1911 Microcontroller
On the LM3S1911, PWM motion control functionality can be achieved through the motion control
features of the general-purpose timers (using the CCP pins).
CCP Pins (see page 199)
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
For support of analog signals, the LM3S1911 microcontroller offers two analog comparators.
1.4.3.1
Analog Comparators (see page 365)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S1911 microcontroller provides two independent integrated analog comparators that can
be configured to drive an output or generate an interrupt .
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 to cause it to start
capturing a sample sequence.
1.4.4
Serial Communications Peripherals
The LM3S1911 controller supports both asynchronous and synchronous serial communications
with:
■ Three fully programmable 16C550-type UARTs
■ Two SSI modules
■ Two I2C modules
1.4.4.1
UART (see page 252)
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 LM3S1911 controller includes three fully programmable 16C550-type UARTs that support data
transfer speeds up to 460.8 Kbps. (Although similar in functionality to a 16C550 UART, it is not
register-compatible.) In addition, each UART is capable of supporting IrDA.
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.
October 09, 2007
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Preliminary
Architectural Overview
1.4.4.2
SSI (see page 293)
Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface.
The LM3S1911 controller includes two SSI modules that provide 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.
Each 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.
Each 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.
Each 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.
1.4.4.3
I2C (see page 330)
The Inter-Integrated Circuit (I2C) bus provides bi-directional data transfer through a two-wire design
(a serial data line SDA and a serial clock line SCL).
The I2C bus interfaces to external I2C devices such as serial memory (RAMs and ROMs), networking
devices, LCDs, tone generators, and so on. The I2C bus may also be used for system testing and
diagnostic purposes in product development and manufacture.
The LM3S1911 controller includes two I2C modules that provide the ability to communicate to other
IC devices over an I2C bus. The I2C bus supports devices that can both transmit and receive (write
and read) data.
Devices on the I2C bus can be designated as either a master or a slave. Each I2C module supports
both sending and receiving data as either a master or a slave, and also supports the simultaneous
operation as both a master and a slave. The four I2C modes are: Master Transmit, Master Receive,
Slave Transmit, and Slave Receive.
®
A Stellaris I2C module can operate at two speeds: Standard (100 Kbps) and Fast (400 Kbps).
Both the I2C master and slave can generate interrupts. The I2C master generates interrupts when
a transmit or receive operation completes (or aborts due to an error). The I2C slave generates
interrupts when data has been sent or requested by a master.
1.4.5
System Peripherals
1.4.5.1
Programmable GPIOs (see page 153)
General-purpose input/output (GPIO) pins offer flexibility for a variety of connections.
®
The Stellaris GPIO module is composed of eight 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 23-60 programmable input/output pins.
The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page
378 for the signals available to each GPIO pin).
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October 09, 2007
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LM3S1911 Microcontroller
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
Four Programmable Timers (see page 193)
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 four 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).
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 (see page 229)
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.
®
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
Memory Peripherals
The LM3S1911 controller offers both single-cycle SRAM and single-cycle Flash memory.
1.4.6.1
SRAM (see page 129)
The LM3S1911 static random access memory (SRAM) controller supports 64 KB SRAM. The internal
®
SRAM of the Stellaris devices is located at offset 0x0000.0000 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 (see page 130)
The LM3S1911 Flash controller supports 256 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.
October 09, 2007
29
Preliminary
Architectural Overview
1.4.7
Additional Features
1.4.7.1
Memory Map (see page 38)
A memory map lists the location of instructions and data in memory. The memory map for the
LM3S1911 controller can be found in “Memory Map” on page 38. Register addresses are given as
a hexadecimal increment, relative to the module's base address as shown in the memory map.
The ARM® Cortex™-M3 Technical Reference Manual provides further information on the memory
map.
1.4.7.2
JTAG TAP Controller (see page 42)
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.
The Luminary Micro 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 Luminary Micro JTAG instructions select the Luminary
Micro TDO outputs. The multiplexer is controlled by the Luminary Micro JTAG controller, which has
comprehensive programming for the ARM, Luminary Micro, and unimplemented JTAG instructions.
1.4.7.3
System Control and Clocks (see page 53)
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.
1.4.7.4
Hibernation Module (see page 110)
The Hibernation module provides logic to switch power off to the main processor and peripherals,
and to wake on external or time-based events. The Hibernation module includes power-sequencing
logic, a real-time clock with a pair of match registers, low-battery detection circuitry, and interrupt
signalling to the processor. It also includes 64 32-bit words of non-volatile memory that can be used
for saving state during hibernation.
1.4.8
Hardware Details
Details on the pins and package can be found in the following sections:
■ “Pin Diagram” on page 377
■ “Signal Tables” on page 378
■ “Operating Characteristics” on page 392
■ “Electrical Characteristics” on page 393
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
■ “Package Information” on page 405
October 09, 2007
31
Preliminary
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.
■ Rapid application execution through Harvard architecture characterized by separate buses for
instruction and data.
■ 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.
■ Migration from the ARM7™ processor family for better performance and power efficiency.
■ 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, and stepper motors.
For more information on the ARM Cortex-M3 processor core, see the ARM® Cortex™-M3 Technical
Reference Manual. For information on SWJ-DP, see the ARM® CoreSight Technical Reference
Manual.
32
October 09, 2007
Preliminary
LM3S1911 Microcontroller
2.1
Block Diagram
Figure 2-1. CPU Block Diagram
Nested
Vectored
Interrupt
Controller
Interrupts
ARM
Cortex-M3
CM3 Core
Sleep
Debug
Instructions
Data
Trace
Port
Interface
Unit
Memory
Protection
Unit
Flash
Patch and
Breakpoint
2.2
Adv. HighPerf. Bus
Access Port
Private
Peripheral
Bus
(external)
Instrumentation
Data
Watchpoint Trace Macrocell
and Trace
ROM
Table
Private Peripheral
Bus
(internal)
Serial Wire JTAG
Debug Port
Serial
Wire
Output
Trace
Port
(SWO)
Adv. Peripheral
Bus
Bus
Matrix
I-code bus
D-code bus
System bus
Functional Description
Important: The ARM® Cortex™-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 on page 33. As
noted in the ARM® Cortex™-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 CoreSight™-compliant
Serial Wire JTAG Debug Port (SWJ-DP) interface. This means Chapter 12, “Debug Port,” of the
®
ARM® Cortex™-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
CoreSight™ Design Kit Technical Reference Manual for details on SWJ-DP.
October 09, 2007
33
Preliminary
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®
Cortex™-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 on page 34.
This is similar to the non-ETM version described in the ARM® Cortex™-M3 Technical Reference
Manual, however, SWJ-DP only provides SWV output for the TPIU.
Figure 2-2. TPIU Block Diagram
2.2.4
Debug
ATB
Slave
Port
ATB
Interface
APB
Slave
Port
APB
Interface
Asynchronous FIFO
Trace Out
(serializer)
Serial Wire
Trace Port
(SWO)
ROM Table
The default ROM table was implemented as described in the ARM® Cortex™-M3 Technical
Reference Manual.
2.2.5
Memory Protection Unit (MPU)
The Memory Protection Unit (MPU) is included on the LM3S1911 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
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October 09, 2007
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LM3S1911 Microcontroller
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
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® Cortex™-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® Cortex™-M3 Technical Reference Manual describes the maximum number of interrupts
and interrupt priorities. The LM3S1911 microcontroller supports 29 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.
October 09, 2007
35
Preliminary
ARM Cortex-M3 Processor Core
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.
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.
SysTick Control and Status Register
Use the SysTick Control and Status Register to enable the SysTick features. The reset is
0x0000.0000.
Bit/Field
Name
31:17
reserved
16
15:3
2
Type Reset Description
RO
0
Software should not rely on the value of a reserved bit. To provide compatibility with
future products, the value of a reserved bit should be preserved across a
read-modify-write operation.
COUNTFLAG R/W
0
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.
RO
0
Software should not rely on the value of a reserved bit. To provide compatibility with
future products, the value of a reserved bit should be preserved across a
read-modify-write operation.
CLKSOURCE R/W
0
0 = external reference clock. (Not implemented for Stellaris microcontrollers.)
reserved
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.
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.
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 0x00FF.FFFF. 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 0x00FF.FFFF. 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.
Bit/Field
Name
31:24
reserved
Type Reset Description
RO
0
Software should not rely on the value of a reserved bit. To provide compatibility with
future products, the value of a reserved bit should be preserved across a read-modify-write
operation.
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October 09, 2007
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LM3S1911 Microcontroller
Bit/Field
23:0
Name
Type Reset Description
RELOAD W1C
-
Value to load into the SysTick Current Value Register when the counter reaches 0.
SysTick Current Value Register
Use the SysTick Current Value Register to find the current value in the register.
Bit/Field
Name
31:24
reserved
23:0
Type Reset Description
RO
CURRENT W1C
0
Software should not rely on the value of a reserved bit. To provide compatibility with
future products, the value of a reserved bit should be preserved across a
read-modify-write operation.
-
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.
SysTick Calibration Value Register
The SysTick Calibration Value register is not implemented.
October 09, 2007
37
Preliminary
Memory Map
3
Memory Map
The memory map for the LM3S1911 controller is provided in Table 3-1 on page 38.
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®
Cortex™-M3 Technical Reference Manual.
Important: In Table 3-1 on page 38, addresses not listed are reserved.
a
Table 3-1. Memory Map
Start
End
Description
For details on
registers, see
page ...
0x0000.0000
0x0003.FFFF
On-chip flash
0x2000.0000
0x2000.FFFF
Bit-banded on-chip SRAM
133
0x2010.0000
0x21FF.FFFF
Reserved non-bit-banded SRAM space
-
0x2200.0000
0x23FF.FFFF
Bit-band alias of 0x2000.0000 through 0x200F.FFFF
129
0x2400.0000
0x3FFF.FFFF
Reserved non-bit-banded SRAM space
-
0x4000.0000
0x4000.0FFF
Watchdog timer
231
0x4000.4000
0x4000.4FFF
GPIO Port A
158
0x4000.5000
0x4000.5FFF
GPIO Port B
158
0x4000.6000
0x4000.6FFF
GPIO Port C
158
0x4000.7000
0x4000.7FFF
GPIO Port D
158
0x4000.8000
0x4000.8FFF
SSI0
304
0x4000.9000
0x4000.9FFF
SSI1
304
0x4000.C000
0x4000.CFFF
UART0
259
0x4000.D000
0x4000.DFFF
UART1
259
0x4000.E000
0x4000.EFFF
UART2
259
0x4002.0000
0x4002.07FF
I2C Master 0
343
0x4002.0800
0x4002.0FFF
I2C Slave 0
356
0x4002.1000
0x4002.17FF
I2C Master 1
343
0x4002.1800
0x4002.1FFF
I2C Slave 1
356
0x4002.4000
0x4002.4FFF
GPIO Port E
158
0x4002.5000
0x4002.5FFF
GPIO Port F
158
0x4002.6000
0x4002.6FFF
GPIO Port G
158
0x4002.7000
0x4002.7FFF
GPIO Port H
158
0x4003.0000
0x4003.0FFF
Timer0
204
0x4003.1000
0x4003.1FFF
Timer1
204
0x4003.2000
0x4003.2FFF
Timer2
204
0x4003.3000
0x4003.3FFF
Timer3
204
0x4003.C000
0x4003.CFFF
Analog Comparators
365
Memory
b
133
c
FiRM Peripherals
Peripherals
38
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Start
End
Description
For details on
registers, see
page ...
0x400F.C000
0x400F.CFFF
Hibernation Module
116
0x400F.D000
0x400F.DFFF
Flash control
133
0x400F.E000
0x400F.EFFF
System control
60
0x4200.0000
0x43FF.FFFF
Bit-banded alias of 0x4000.0000 through 0x400F.FFFF
-
0xE000.0000
0xE000.0FFF
Instrumentation Trace Macrocell (ITM)
0xE000.1000
0xE000.1FFF
Data Watchpoint and Trace (DWT)
0xE000.2000
0xE000.2FFF
Flash Patch and Breakpoint (FPB)
0xE000.3000
0xE000.DFFF
Reserved
ARM®
Cortex™-M3
Technical
Reference
Manual
0xE000.E000
0xE000.EFFF
Nested Vectored Interrupt Controller (NVIC)
0xE000.F000
0xE003.FFFF
Reserved
0xE004.0000
0xE004.0FFF
Trace Port Interface Unit (TPIU)
0xE004.1000
0xE004.1FFF
Reserved
-
0xE004.2000
0xE00F.FFFF
Reserved
-
0xE010.0000
0xFFFF.FFFF
Reserved for vendor peripherals
-
Private Peripheral Bus
a. All reserved space returns a bus fault when read or written.
b. The unavailable flash will bus fault throughout this range.
c. The unavailable SRAM will bus fault throughout this range.
October 09, 2007
39
Preliminary
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 on page 40 lists all the exceptions. Software can set eight priority levels on seven of these
exceptions (system handlers) as well as on 29 interrupts (listed in Table 4-2 on page 41).
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® Cortex™-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®
Cortex™-M3 Technical Reference Manual for more information on exceptions and interrupts.
Note:
In Table 4-2 on page 41 interrupts not listed are reserved.
Table 4-1. Exception Types
Exception Type
Position
-
0
Reset
1
Non-Maskable
Interrupt (NMI)
2
a
Priority
Description
-
Stack top is loaded from first entry of vector table on reset.
-3 (highest) 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.
-2
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
-1
All classes of Fault, when the fault cannot activate due to priority or the
configurable fault handler has been disabled. This is synchronous.
Memory Management
4
settable
Bus Fault
5
settable
MPU mismatch, including access violation and no match. This is
synchronous.
The priority of this exception can be changed.
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.
Usage Fault
SVCall
6
settable
7-10
-
11
settable
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.
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October 09, 2007
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LM3S1911 Microcontroller
Exception Type
Position
a
Priority
Description
Debug Monitor
12
settable
-
13
-
PendSV
14
settable
Pendable request for system service. This is asynchronous and only
pended by software.
15
settable
System tick timer has fired. This is asynchronous.
16 and
above
settable
Asserted from outside the ARM Cortex-M3 core and fed through the NVIC
(prioritized). These are all asynchronous. Table 4-2 on page 41 lists the
interrupts on the LM3S1911 controller.
SysTick
Interrupts
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.
a. 0 is the default priority for all the settable priorities.
Table 4-2. Interrupts
Interrupt (Bit in Interrupt Registers) Description
0
GPIO Port A
1
GPIO Port B
2
GPIO Port C
3
GPIO Port D
4
GPIO Port E
5
UART0
6
UART1
7
SSI0
8
I2C0
18
Watchdog timer
19
Timer0 A
20
Timer0 B
21
Timer1 A
22
Timer1 B
23
Timer2 A
24
Timer2 B
25
Analog Comparator 0
26
Analog Comparator 1
28
System Control
29
Flash Control
30
GPIO Port F
31
GPIO Port G
32
GPIO Port H
33
UART2
34
SSI1
35
Timer3 A
36
Timer3 B
37
I2C1
43
Hibernation Module
44-47
Reserved
October 09, 2007
41
Preliminary
JTAG Interface
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 Luminary Micro 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 Luminary Micro JTAG instructions select the Luminary
Micro TDO outputs. The multiplexer is controlled by the Luminary Micro JTAG controller, which has
comprehensive programming for the ARM, Luminary Micro, 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® Cortex™-M3 Technical Reference Manual for more information on the ARM JTAG
controller.
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October 09, 2007
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LM3S1911 Microcontroller
5.1
Block Diagram
Figure 5-1. JTAG Module Block Diagram
TRST
TCK
TMS
TDI
TAP Controller
Instruction Register (IR)
BYPASS Data Register
TDO
Boundary Scan Data Register
IDCODE Data Register
ABORT Data Register
DPACC Data Register
APACC Data Register
Cortex-M3
Debug
Port
5.2
Functional Description
A high-level conceptual drawing of the JTAG module is shown in Figure 5-1 on page 43. 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 49 for a list of implemented instructions).
See “JTAG and Boundary Scan” on page 400 for JTAG timing diagrams.
October 09, 2007
43
Preliminary
JTAG Interface
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 on page 44. Detailed information on each pin
follows.
Table 5-1. JTAG Port Pins Reset State
5.2.1.1
Pin Name
Data Direction
Internal Pull-Up
Internal Pull-Down
Drive Strength
Drive Value
TRST
Input
Enabled
Disabled
N/A
N/A
TCK
Input
Enabled
Disabled
N/A
N/A
TMS
Input
Enabled
Disabled
N/A
N/A
TDI
Input
Enabled
Disabled
N/A
N/A
TDO
Output
Enabled
Disabled
2-mA driver
High-Z
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 46.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 46. 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.
October 09, 2007
45
Preliminary
JTAG Interface
Figure 5-2. Test Access Port State Machine
Test Logic Reset
1
0
Run Test Idle
0
Select DR Scan
1
Select IR Scan
1
0
1
0
Capture DR
1
Capture IR
0
0
Shift DR
Shift IR
0
1
Exit 1 DR
Exit 1 IR
1
Pause IR
0
1
Exit 2 DR
0
1
0
Exit 2 IR
1
1
Update DR
5.2.3
1
0
Pause DR
1
0
1
0
0
1
0
Update IR
1
0
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 “Register Descriptions” 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 is described below.
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October 09, 2007
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LM3S1911 Microcontroller
5.2.4.1
GPIO Functionality
When the controller is reset with either a POR or RST, the JTAG/SWD port pins default to their
JTAG/SWD configurations. The default configuration includes enabling digital functionality (setting
GPIODEN to 1), enabling the pull-up resistors (setting GPIOPUR to 1), and enabling the alternate
hardware function (setting GPIOAFSEL to 1) for the PB7 and PC[3:0] JTAG/SWD 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/SWD 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 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.
The commit control registers provide a layer of protection against accidental programming of critical
hardware peripherals. Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL)
register (see page 168) are not committed to storage unless the GPIO Lock (GPIOLOCK) register
(see page 178) has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register
(see page 179) have been set to 1.
Recovering a "Locked" Device
If software configures any of the JTAG/SWD pins as GPIO and loses the ability to communicate
with the debugger, there is a debug sequence that can be used to recover the device. Performing
a total of ten JTAG-to-SWD and SWD-to-JTAG switch sequences while holding the device in reset
mass erases the flash memory. The sequence to recover the device is:
1. Assert and hold the RST signal.
2. Perform the JTAG-to-SWD switch sequence.
3. Perform the SWD-to-JTAG switch sequence.
4. Perform the JTAG-to-SWD switch sequence.
5. Perform the SWD-to-JTAG switch sequence.
6. Perform the JTAG-to-SWD switch sequence.
7. Perform the SWD-to-JTAG switch sequence.
8. Perform the JTAG-to-SWD switch sequence.
9. Perform the SWD-to-JTAG switch sequence.
10. Perform the JTAG-to-SWD switch sequence.
11. Perform the SWD-to-JTAG switch sequence.
October 09, 2007
47
Preliminary
JTAG Interface
12. Release the RST signal.
The JTAG-to-SWD and SWD-to-JTAG switch sequences are described in “ARM Serial Wire Debug
(SWD)” on page 48. When performing switch sequences for the purpose of recovering the debug
capabilities of the device, only steps 1 and 2 of the switch sequence need to be performed.
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, Test Logic Reset, Test Logic Reset, Run Test
Idle, Run Test Idle, Select DR, Select IR, Test Logic Reset, Test Logic Reset, Run Test Idle, Run
Test Idle, Select DR, Select IR, and Test Logic Reset states.
Stepping through this sequences of the TAP state machine enables the SWD interface and disables
the JTAG interface. For more information on this operation and the SWD interface, see the ARM®
Cortex™-M3 Technical Reference Manual and the ARM® 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.
JTAG-to-SWD Switching
To switch the operating mode of the Debug Access Port (DAP) from JTAG to SWD mode, the
external debug hardware must send a switch sequence to the device. The 16-bit switch sequence
for switching to SWD mode is defined as b1110011110011110, transmitted LSB first. This can also
be represented as 16'hE79E when transmitted LSB first. The complete switch sequence should
consist of the following transactions on the TCK/SWCLK and TMS/SWDIO signals:
1. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that both JTAG and
SWD are in their reset/idle states.
2. Send the 16-bit JTAG-to-SWD switch sequence, 16'hE79E.
3. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that if SWJ-DP was
already in SWD mode, before sending the switch sequence, the SWD goes into the line reset
state.
SWD-to-JTAG Switching
To switch the operating mode of the Debug Access Port (DAP) from SWD to JTAG mode, the
external debug hardware must send a switch sequence to the device. The 16-bit switch sequence
for switching to JTAG mode is defined as b1110011110011110, transmitted LSB first. This can also
be represented as 16'hE73C when transmitted LSB first. The complete switch sequence should
consist of the following transactions on the TCK/SWCLK and TMS/SWDIO signals:
1. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that both JTAG and
SWD are in their reset/idle states.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
2. Send the 16-bit SWD-to-JTAG switch sequence, 16'hE73C.
3. Send at least 5 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that if SWJ-DP was
already in JTAG mode, before sending the switch sequence, the JTAG goes into the Test Logic
Reset state.
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.
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 on page 49. A detailed explanation of each instruction, along
with its associated Data Register, follows.
Table 5-2. JTAG Instruction Register Commands
IR[3:0]
Instruction
0000
EXTEST
Drives the values preloaded into the Boundary Scan Chain by the SAMPLE/PRELOAD
instruction onto the pads.
0001
INTEST
Drives the values preloaded into the Boundary Scan Chain by the SAMPLE/PRELOAD
instruction into the controller.
0010
5.4.1.1
Description
SAMPLE / PRELOAD Captures the current I/O values and shifts the sampled values out of the Boundary Scan
Chain while new preload data is shifted in.
1000
ABORT
Shifts data into the ARM Debug Port Abort Register.
1010
DPACC
Shifts data into and out of the ARM DP Access Register.
1011
APACC
Shifts data into and out of the ARM AC Access Register.
1110
IDCODE
Loads manufacturing information defined by the IEEE Standard 1149.1 into the IDCODE
chain and shifts it out.
1111
BYPASS
Connects TDI to TDO through a single Shift Register chain.
All Others
Reserved
Defaults to the BYPASS instruction to ensure that TDI is always connected to TDO.
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
October 09, 2007
49
Preliminary
JTAG Interface
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 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 52 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 52 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 52 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 52 for more information.
50
October 09, 2007
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LM3S1911 Microcontroller
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 51 for more
information.
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 51 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 on page 51. 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 0x3BA00477. 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. IDCODE Register Format
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 on page 52. 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.
October 09, 2007
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Preliminary
JTAG Interface
Figure 5-4. BYPASS Register Format
5.4.2.3
Boundary Scan Data Register
The format of the Boundary Scan Data Register is shown in Figure 5-5 on page 52. 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
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. Boundary Scan Register Format
TDI
I
N
O
U
T
O
E
...
GPIO PB6
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
O TDO
E
GPIO n
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®
Cortex™-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®
Cortex™-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®
Cortex™-M3 Technical Reference Manual.
52
October 09, 2007
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LM3S1911 Microcontroller
6
System Control
System control determines the overall operation of the device. It provides information about the
device, controls the clocking to the core and individual peripherals, and handles reset detection and
reporting.
6.1
Functional Description
The System Control module provides the following capabilities:
■ Device identification, see “Device Identification” on page 53
■ Local control, such as reset (see “Reset Control” on page 53), power (see “Power
Control” on page 56) and clock control (see “Clock Control” on page 56)
■ System control (Run, Sleep, and Deep-Sleep modes), see “System Control” on page 58
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.
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
CMOD0 and CMOD1 Test-Mode Control Pins
Two pins, CMOD0 and CMOD1, are defined for use by Luminary Micro for testing the devices during
manufacture. They have no end-user function and should not be used. The CMOD pins should be
connected to ground.
6.1.2.2
Reset Sources
The controller has five sources of reset:
1. External reset input pin (RST) assertion, see “RST Pin Assertion” on page 53.
2. Power-on reset (POR), see “Power-On Reset (POR)” on page 54.
3. Internal brown-out (BOR) detector, see “Brown-Out Reset (BOR)” on page 54.
4. Software-initiated reset (with the software reset registers), see “Software Reset” on page 55.
5. A watchdog timer reset condition violation, see “Watchdog Timer Reset” on page 55.
After a reset, the Reset Cause (RESC) register is set with the reset cause. The bits in this register
are sticky and maintain their state across multiple reset sequences, except when an internal POR
is the cause, and then all the other bits in the RESC register are cleared except for the POR indicator.
6.1.2.3
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 42). The external reset sequence is as
follows:
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Preliminary
System Control
1. The external reset pin (RST) is asserted and then de-asserted.
2. The internal reset is released and the core loads from memory the initial stack pointer, the initial
program counter, the first instruction designated by the program counter, and begins execution.
A few clocks cycles from RST de-assertion to the start of the reset sequence is necessary for
synchronization.
The external reset timing is shown in Figure 19-10 on page 403.
6.1.2.4
Power-On Reset (POR)
The Power-On Reset (POR) circuit monitors the power supply voltage (VDD). The POR circuit
generates a reset signal to the internal logic when the power supply ramp reaches a threshold value
(VTH). If the application only uses the POR circuit, the RST input needs to be connected to the power
supply (VDD) through a pull-up resistor (1K to 10K Ω).
The device must be operating within the specified operating parameters at the point when the on-chip
power-on reset pulse is complete. The 3.3-V power supply to the device must reach 3.0 V within
10 msec of it crossing 2.0 V to guarantee proper operation. For applications that require the use of
an external reset to hold the device in reset longer than the internal POR, the RST input may be
used with the circuit as shown in Figure 6-1 on page 54.
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 (D1) 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. The internal reset is released and the core loads from memory the initial stack pointer, the initial
program counter, the first instruction designated by the program counter, and 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 19-11 on page 403.
Note:
6.1.2.5
The power-on reset also resets the JTAG controller. An external reset does not.
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 the power supply (VDD) drops
below a brown-out threshold voltage (VBTH). If a brown-out condition is detected, the system may
generate a controller interrupt or a system reset.
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October 09, 2007
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LM3S1911 Microcontroller
Brown-out resets are controlled with the Power-On and Brown-Out Reset Control (PBORCTL)
register. The BORIOR bit in the PBORCTL register must be set for a brown-out condition to trigger
a reset.
The brown-out reset is equivelent to an assertion of the external RST input and the reset is held
active until the proper VDD level is restored. The RESC register can be examined in the reset interrupt
handler to determine if a Brown-Out condition was the cause of the reset, thus allowing software to
determine what actions are required to recover.
The internal Brown-Out Reset timing is shown in Figure 19-12 on page 403.
6.1.2.6
Software Reset
Software can reset a specific peripheral or generate a reset to the entire system .
Peripherals can be individually reset by software via three registers that control reset signals to each
peripheral (see the SRCRn registers). If the bit position corresponding to a peripheral is set and
subsequently cleared, 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 58). 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 by 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 is 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 deasserted and the controller loads from memory 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 19-13 on page 404.
6.1.2.7
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, 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.
3. The internal reset is released and the controller loads from memory the initial stack pointer, the
initial program counter, the first instruction designated by the program counter, and begins
execution.
October 09, 2007
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Preliminary
System Control
The watchdog reset timing is shown in Figure 19-14 on page 404.
6.1.3
Power Control
®
The Stellaris microcontroller provides an integrated LDO regulator that may be used to provide
power to the majority of the controller's internal logic. The LDO regulator provides software a
mechanism to adjust the regulated value, in small increments (VSTEP), over the range of 2.25 V
to 2.75 V (inclusive)—or 2.5 V ± 10%. The adjustment is made by changing the value of the VADJ
field in the LDO Power Control (LDOPCTL) register.
Note:
6.1.4
The use of the LDO is optional. The internal logic may be supplied by the on-chip LDO or
by an external regulator. If the LDO is used, the LDO output pin is connected to the VDD25
pins on the printed circuit board. The LDO requires decoupling capacitors on the printed
circuit board. If an external regulator is used, it is strongly recommended that the external
regulator supply the controller only and not be shared with other devices on the printed
circuit board.
Clock Control
System control determines the control of clocks in this part.
6.1.4.1
Fundamental Clock Sources
There are four clock sources for use in the device:
■ Internal Oscillator (IOSC): The internal oscillator is an on-chip clock source. It does not require
the use of any external components. The frequency of the internal oscillator is 12 MHz ± 30%.
Applications that do not depend on accurate clock sources may use this clock source to reduce
system cost. The internal oscillator is the clock source the device uses during and following POR.
If the main oscillator is required, software must enable the main oscillator following reset and
allow the main oscillator to stabilize before changing the clock reference.
■ Main Oscillator: The main oscillator provides a frequency-accurate clock source by one of two
means: an external single-ended clock source is connected to the OSC0 input pin, or an external
crystal is connected across the OSC0 input and OSC1 output pins. The crystal value allowed
depends on whether the main oscillator is used as the clock reference source to the PLL. If so,
the crystal must be one of the supported frequencies between 3.579545 MHz through 8.192
MHz (inclusive). If the PLL is not being used, the crystal may be any one of the supported
frequencies between 1 MHz and 8.192 MHz. The single-ended clock source range is from DC
through the specified speed of the device. The supported crystals are listed in the XTAL bit in
the RCC register (see page 69).
■ Internal 30-kHz Oscillator: The internal 30-kHz oscillator is similar to the internal oscillator,
except that it provides an operational frequency of 30 kHz ± 30%. It is intended for use during
Deep-Sleep power-saving modes. This power-savings mode benefits from reduced internal
switching and also allows the main oscillator to be powered down.
■ External Real-Time Oscillator: The external real-time oscillator provides a low-frequency,
accurate clock reference. It is intended to provide the system with a real-time clock source. The
real-time oscillator is part of the Hibernation Module (“Hibernation Module” on page 110) and may
also provide an accurate source of Deep-Sleep or Hibernate mode power savings.
The internal system clock (sysclk), is derived from any of the four sources plus two others: the output
of the internal PLL, and the internal oscillator divided by four (3 MHz ± 30%). The frequency of the
PLL clock reference must be in the range of 3.579545 MHz to 8.192 MHz (inclusive).
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October 09, 2007
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LM3S1911 Microcontroller
The Run-Mode Clock Configuration (RCC) and Run-Mode Clock Configuration 2 (RCC2)
registers provide control for the system clock. The RCC2 register is provided to extend fields that
offer additional encodings over the RCC register. When used, the RCC2 register field values are
used by the logic over the corresponding field in the RCC register. In particular, RCC2 provides for
a larger assortment of clock configuration options.
6.1.4.2
Crystal Configuration for the Main Oscillator (MOSC)
The main oscillator supports the use of a select number of crystals. If the main oscillator is used by
the PLL as a reference clock, the supported range of crystals is 3.579545 to 8.192 MHz, otherwise,
the range of supported crystals is 1 to 8.192 MHz.
The XTAL bit in the RCC register (see page 69) describes the available crystal choices and default
programming values.
Software configures the RCC register XTAL field with the crystal number. If the PLL is used in the
design, the XTAL field value is internally translated to the PLL settings.
6.1.4.3
PLL Frequency Configuration
The PLL is disabled by default during power-on reset and is enabled later by software if required.
Software configures the PLL input reference clock source, specifies the output divisor to set the
system clock frequency, and enables the PLL to drive the output.
If the main oscillator provides the clock reference to the PLL, the translation provided by hardware
and used to program the PLL is available for software in the XTAL to PLL Translation (PLLCFG)
register (see page 73). The internal translation provides a translation within ± 1% of the targeted
PLL VCO frequency.
The XTAL bit in the RCC register (see page 69) 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. Any time the XTAL field changes, the new settings
are translated and the internal PLL settings are updated.
6.1.4.4
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/RCC2 register fields (see page 69 and page 74).
6.1.4.5
PLL Operation
If the PLL configuration is changed, the PLL output frequency is unstable until it reconverges (relocks)
to the new setting. The time between the configuration change and relock is TREADY (see Table
19-6 on page 396). 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—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
October 09, 2007
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Preliminary
System Control
to 0x1200 (that is, ~600 μs at an 8.192 MHz external oscillator clock). Hardware is provided to 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/RCC2 register is switched to use the PLL.
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.
In Run mode, the processor executes code. In Sleep mode, the clock frequency of the active
peripherals is unchanged, but the processor is not clocked and therefore no longer executes code.
In Deep-Sleep mode, the clock frequency of the active peripherals may change (depending on the
Run mode clock configuration) in addition to the processor clock being stopped. 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 below.
There are four levels of operation for the device defined as:
■ 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.
■ Sleep Mode. Sleep mode is entered by the Cortex-M3 core executing a WFI (Wait for
Interrupt) instruction. Any properly configured interrupt event in the system will bring the
processor back into Run mode. See the system control NVIC section of the ARM® Cortex™-M3
Technical Reference Manual for more details.
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 the RCC register) 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.
■ Deep-Sleep Mode. Deep-Sleep mode is entered by first writing the Deep Sleep Enable bit in
the ARM Cortex-M3 NVIC system control register and then executing a WFI instruction. Any
properly configured interrupt event in the system will bring the processor back into Run mode.
See the system control NVIC section of the ARM® Cortex™-M3 Technical Reference Manual
for more details.
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 the RCC
register) or the RCGCn register when 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. 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 will power the PLL down and override the SYSDIV field of the active
RCC/RCC2 register to be /16 or /64, respectively. 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 before enabling the clocks that had been stopped during the Deep-Sleep
duration.
■ Hibernate Mode. In this mode, the power supplies are turned off to the main part of the device
and only the Hibernation module's circuitry is active. An external wake event or RTC event is
required to bring the device back to Run mode. The Cortex-M3 processor and peripherals outside
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October 09, 2007
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LM3S1911 Microcontroller
of the Hibernation module see a normal "power on" sequence and the processor starts running
code. It can determine that it has been restarted from Hibernate mode by inspecting the
Hibernation module registers.
6.2
Initialization and Configuration
The PLL is configured using direct register writes to the RCC/RCC2 register. If the RCC2 register
is being used, the USERCC2 bit must be set and the appropriate RCC2 bit/field is used. 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 bit in
RCC/RCC2. Setting the XTAL field automatically pulls valid PLL configuration data for the
appropriate crystal, and clearing the PWRDN bit powers and enables the PLL and its output.
3. Select the desired system divider (SYSDIV) in RCC/RCC2 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.
5. Enable use of the PLL by clearing the BYPASS bit in RCC/RCC2.
6.3
Register Map
Table 6-1 on page 59 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
0x400F.E000.
Note:
Spaces in the System Control register space that are not used are reserved for future or
internal use by Luminary Micro, Inc. Software should not modify any reserved memory
address.
Table 6-1. System Control Register Map
Description
See
page
Offset
Name
Type
Reset
0x000
DID0
RO
-
Device Identification 0
61
0x004
DID1
RO
-
Device Identification 1
77
0x008
DC0
RO
0x00FF.007F
Device Capabilities 0
79
0x010
DC1
RO
0x0000.30DF
Device Capabilities 1
80
0x014
DC2
RO
0x030F.5037
Device Capabilities 2
82
0x018
DC3
RO
0x3F00.0FC0
Device Capabilities 3
84
0x01C
DC4
RO
0x0000.C0FF
Device Capabilities 4
86
0x030
PBORCTL
R/W
0x0000.7FFD
Brown-Out Reset Control
63
0x034
LDOPCTL
R/W
0x0000.0000
LDO Power Control
64
October 09, 2007
59
Preliminary
System Control
See
page
Offset
Name
Type
Reset
0x040
SRCR0
R/W
0x00000000
Software Reset Control 0
106
0x044
SRCR1
R/W
0x00000000
Software Reset Control 1
107
0x048
SRCR2
R/W
0x00000000
Software Reset Control 2
109
0x050
RIS
RO
0x0000.0000
Raw Interrupt Status
65
0x054
IMC
R/W
0x0000.0000
Interrupt Mask Control
66
0x058
MISC
R/W1C
0x0000.0000
Masked Interrupt Status and Clear
67
0x05C
RESC
R/W
-
Reset Cause
68
0x060
RCC
R/W
0x07A0.3AD1
Run-Mode Clock Configuration
69
0x064
PLLCFG
RO
-
XTAL to PLL Translation
73
0x070
RCC2
R/W
0x0780.2800
Run-Mode Clock Configuration 2
74
0x100
RCGC0
R/W
0x00000040
Run Mode Clock Gating Control Register 0
88
0x104
RCGC1
R/W
0x00000000
Run Mode Clock Gating Control Register 1
91
0x108
RCGC2
R/W
0x00000000
Run Mode Clock Gating Control Register 2
100
0x110
SCGC0
R/W
0x00000040
Sleep Mode Clock Gating Control Register 0
89
0x114
SCGC1
R/W
0x00000000
Sleep Mode Clock Gating Control Register 1
94
0x118
SCGC2
R/W
0x00000000
Sleep Mode Clock Gating Control Register 2
102
0x120
DCGC0
R/W
0x00000040
Deep Sleep Mode Clock Gating Control Register 0
90
0x124
DCGC1
R/W
0x00000000
Deep Sleep Mode Clock Gating Control Register 1
97
0x128
DCGC2
R/W
0x00000000
Deep Sleep Mode Clock Gating Control Register 2
104
0x144
DSLPCLKCFG
R/W
0x0780.0000
Deep Sleep Clock Configuration
76
6.4
Description
Register Descriptions
All addresses given are relative to the System Control base address of 0x400F.E000.
60
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 1: Device Identification 0 (DID0), offset 0x000
This register identifies the version of the device.
Device Identification 0 (DID0)
Base 0x400F.E000
Offset 0x000
Type RO, reset 31
30
reserved
Type
Reset
29
28
27
26
VER
25
24
23
22
21
20
reserved
18
17
16
CLASS
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
MAJOR
Type
Reset
19
MINOR
Bit/Field
Name
Type
Reset
31
reserved
RO
0
30:28
VER
RO
0x1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
DID0 Version
This field defines the DID0 register format version. The version number
is numeric. The value of the VER field is encoded as follows:
Value Description
0x1
First revision of the DID0 register format, for Stellaris®
Fury-class devices.
27:24
reserved
RO
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
23:16
CLASS
RO
0x1
Device Class
The CLASS field value identifies the internal design from which all mask
sets are generated for all devices in a particular product line. The CLASS
field value is changed for new product lines, for changes in fab process
(for example, a remap or shrink), or any case where the MAJOR or MINOR
fields require differentiation from prior devices. The value of the CLASS
field is encoded as follows (all other encodings are reserved):
Value Description
0x0
Stellaris® Sandstorm-class devices.
0x1
Stellaris® Fury-class devices.
October 09, 2007
61
Preliminary
System Control
Bit/Field
Name
Type
Reset
15:8
MAJOR
RO
-
Description
Major Revision
This field specifies the major revision number of the device. The major
revision reflects changes to base layers of the design. 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:
Value Description
0x0
Revision A (initial device)
0x1
Revision B (first base layer revision)
0x2
Revision C (second base layer revision)
and so on.
7:0
MINOR
RO
-
Minor Revision
This field specifies the minor revision number of the device. The minor
revision reflects changes to the metal layers of the design. The MINOR
field value is reset when the MAJOR field is changed. This field is numeric
and is encoded as follows:
Value Description
0x0
Initial device, or a major revision update.
0x1
First metal layer change.
0x2
Second metal layer change.
and so on.
62
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 2: Brown-Out Reset Control (PBORCTL), offset 0x030
This register is responsible for controlling reset conditions after initial power-on reset.
Brown-Out Reset Control (PBORCTL)
Base 0x400F.E000
Offset 0x030
Type R/W, reset 0x0000.7FFD
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
31:2
reserved
RO
0x0
1
BORIOR
R/W
0
BORIOR reserved
R/W
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
63
Preliminary
System Control
Register 3: LDO Power Control (LDOPCTL), offset 0x034
The VADJ field in this register adjusts the on-chip output voltage (VOUT).
LDO Power Control (LDOPCTL)
Base 0x400F.E000
Offset 0x034
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
VADJ
RO
0
Bit/Field
Name
Type
Reset
31:6
reserved
RO
0
5:0
VADJ
R/W
0x0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
LDO Output Voltage
This field sets the on-chip output voltage. The programming values for
the VADJ field are provided below.
Value
VOUT (V)
0x00
2.50
0x01
2.45
0x02
2.40
0x03
2.35
0x04
2.30
0x05
2.25
0x06-0x3F Reserved
0x1B
2.75
0x1C
2.70
0x1D
2.65
0x1E
2.60
0x1F
2.55
64
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 4: Raw Interrupt Status (RIS), offset 0x050
Central location for system control raw interrupts. These are set and cleared by hardware.
Raw Interrupt Status (RIS)
Base 0x400F.E000
Offset 0x050
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
PLLLRIS
RO
0
reserved
BORRIS reserved
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
PLLLRIS
RO
0
PLL Lock Raw Interrupt Status
This bit is set when the PLL TREADY Timer asserts.
5:2
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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 is currently active. This is an unregistered signal
from the brown-out detection circuit. 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
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
65
Preliminary
System Control
Register 5: Interrupt Mask Control (IMC), offset 0x054
Central location for system control interrupt masks.
Interrupt Mask Control (IMC)
Base 0x400F.E000
Offset 0x054
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
BORIM
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
PLLLIM
R/W
0
reserved
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
PLLLIM
R/W
0
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.
5:2
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
BORIM
R/W
0
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
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
66
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 6: 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 65).
Masked Interrupt Status and Clear (MISC)
Base 0x400F.E000
Offset 0x058
Type R/W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
PLLLMIS
R/W1C
0
reserved
BORMIS reserved
R/W1C
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
PLLLMIS
R/W1C
0
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.
5:2
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
BORMIS
R/W1C
0
BOR Masked Interrupt Status
The BORMIS is simply the BORRIS ANDed with the mask value, BORIM.
0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
67
Preliminary
System Control
Register 7: Reset Cause (RESC), offset 0x05C
This register is set with the reset cause after reset. 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.
Reset Cause (RESC)
Base 0x400F.E000
Offset 0x05C
Type R/W, reset 31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
LDO
SW
WDT
BOR
POR
EXT
RO
0
RO
0
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
reserved
Type
Reset
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
Description
31:6
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
LDO
R/W
-
LDO Reset
When set, indicates the LDO circuit has lost regulation and has
generated a reset event.
4
SW
R/W
-
Software Reset
When set, indicates a software reset is the cause of the reset event.
3
WDT
R/W
-
Watchdog Timer Reset
When set, indicates a watchdog reset is the cause of the reset event.
2
BOR
R/W
-
Brown-Out Reset
When set, indicates a brown-out reset is the cause of the reset event.
1
POR
R/W
-
Power-On Reset
When set, indicates a power-on reset is the cause of the reset event.
0
EXT
R/W
-
External Reset
When set, indicates an external reset (RST assertion) is the cause of
the reset event.
68
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 8: Run-Mode Clock Configuration (RCC), offset 0x060
This register is defined to provide source control and frequency speed.
Run-Mode Clock Configuration (RCC)
Base 0x400F.E000
Offset 0x060
Type R/W, reset 0x07A0.3AD1
31
30
29
28
RO
0
RO
0
RO
0
RO
0
15
14
13
12
reserved
Type
Reset
reserved
Type
Reset
RO
0
RO
0
27
26
25
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
11
10
9
8
R/W
1
R/W
0
ACG
24
RO
1
R/W
1
21
20
19
R/W
0
RO
0
RO
0
RO
0
7
6
5
4
3
R/W
1
R/W
1
R/W
0
SYSDIV
RO
0
22
XTAL
Bit/Field
Name
Type
Reset
31:28
reserved
RO
0x0
27
ACG
R/W
0
18
17
16
RO
0
RO
0
RO
0
2
1
0
reserved
USESYSDIV
PWRDN reserved BYPASS reserved
R/W
1
23
OSCSRC
R/W
1
reserved
RO
0
RO
0
IOSCDIS MOSCDIS
R/W
0
R/W
1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Auto Clock Gating
This bit specifies whether the system uses the Sleep-Mode Clock
Gating Control (SCGCn) registers and Deep-Sleep-Mode Clock
Gating Control (DCGCn) registers 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 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.
October 09, 2007
69
Preliminary
System Control
Bit/Field
Name
Type
Reset
26:23
SYSDIV
R/W
0xF
Description
System Clock Divisor
Specifies which divisor is used to generate the system clock from the
PLL output.
The PLL VCO frequency is 400 MHz.
Value Divisor (BYPASS=1) Frequency (BYPASS=0)
0x0
reserved
reserved
0x1
/2
reserved
0x2
/3
reserved
0x3
/4
50 MHz
0x4
/5
40 MHz
0x5
/6
33.33 MHz
0x6
/7
28.57 MHz
0x7
/8
25 MHz
0x8
/9
22.22 MHz
0x9
/10
20 MHz
0xA
/11
18.18 MHz
0xB
/12
16.67 MHz
0xC
/13
15.38 MHz
0xD
/14
14.29 MHz
0xE
/15
13.33 MHz
0xF
/16
12.5 MHz (default)
When reading the Run-Mode Clock Configuration (RCC) register (see
page 69), 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
Enable System Clock Divider
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.
21:14
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
13
PWRDN
R/W
1
PLL Power Down
This bit connects to the PLL PWRDN input. The reset value of 1 powers
down the PLL.
12
reserved
RO
1
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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.
70
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
10
reserved
RO
0
9:6
XTAL
R/W
0xB
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Crystal Value
This field specifies the crystal value attached to the main oscillator. The
encoding for this field is provided below.
Value
5:4
OSCSRC
R/W
0x1
Crystal Frequency (MHz)
Not Using the PLL
Crystal Frequency (MHz)
Using the PLL
0x0
1.000
reserved
0x1
1.8432
reserved
0x2
2.000
reserved
0x3
2.4576
reserved
0x4
3.579545 MHz
0x5
3.6864 MHz
0x6
4 MHz
0x7
4.096 MHz
0x8
4.9152 MHz
0x9
5 MHz
0xA
5.12 MHz
0xB
6 MHz (reset value)
0xC
6.144 MHz
0xD
7.3728 MHz
0xE
8 MHz
0xF
8.192 MHz
Oscillator Source
Picks among the four input sources for the OSC. The values are:
Value Input Source
3:2
reserved
RO
0x0
1
IOSCDIS
R/W
0
0x0
Main oscillator (default)
0x1
Internal oscillator (default)
0x2
Internal oscillator / 4 (this is necessary if used as input to PLL)
0x3
reserved
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Internal Oscillator Disable
0: Internal oscillator (IOSC) is enabled.
1: Internal oscillator is disabled.
October 09, 2007
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System Control
Bit/Field
Name
Type
Reset
0
MOSCDIS
R/W
1
Description
Main Oscillator Disable
0: Main oscillator is enabled.
1: Main oscillator is disabled (default).
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October 09, 2007
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LM3S1911 Microcontroller
Register 9: 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 69).
The PLL frequency is calculated using the PLLCFG field values, as follows:
PLLFreq = OSCFreq * F / (R + 1)
XTAL to PLL Translation (PLLCFG)
Base 0x400F.E000
Offset 0x064
Type RO, reset 31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
RO
-
reserved
Type
Reset
OD
Type
Reset
RO
-
F
Bit/Field
Name
Type
Reset
31:16
reserved
RO
0x0
15:14
OD
RO
-
R
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
PLL OD Value
This field specifies the value supplied to the PLL’s OD input.
Value Description
13:5
F
RO
-
0x0
Divide by 1
0x1
Divide by 2
0x2
Divide by 4
0x3
Reserved
PLL F Value
This field specifies the value supplied to the PLL’s F input.
4:0
R
RO
-
PLL R Value
This field specifies the value supplied to the PLL’s R input.
October 09, 2007
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Preliminary
System Control
Register 10: Run-Mode Clock Configuration 2 (RCC2), offset 0x070
This register overrides the RCC equivalent register fields when the USERCC2 bit is set. This allows
RCC2 to be used to extend the capabilities, while also providing a means to be backward-compatible
to previous parts. The fields within the RCC2 register occupy the same bit positions as they do
within the RCC register as LSB-justified.
The SYSDIV2 field is wider so that additional larger divisors are possible. This allows a lower system
clock frequency for improved Deep Sleep power consumption.
Run-Mode Clock Configuration 2 (RCC2)
Base 0x400F.E000
Offset 0x070
Type R/W, reset 0x0780.2800
31
30
USERCC2
Type
Reset
R/W
0
RO
0
15
14
reserved
Type
Reset
RO
0
29
28
27
reserved
RO
0
26
25
24
23
22
20
R/W
0
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
RO
0
13
12
11
10
9
8
7
6
PWRDN2 reserved BYPASS2
RO
0
R/W
1
reserved
RO
0
19
18
17
16
reserved
RO
0
R/W
1
21
SYSDIV2
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
5
4
3
2
1
0
RO
0
RO
0
OSCSRC2
RO
0
Bit/Field
Name
Type
Reset
Description
31
USERCC2
R/W
0
Use RCC2
R/W
0
R/W
0
reserved
R/W
0
RO
0
RO
0
When set, overrides the RCC register fields.
30:29
reserved
RO
0x0
28:23
SYSDIV2
R/W
0x0F
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
System Clock Divisor
Specifies which divisor is used to generate the system clock from the
PLL output.
The PLL VCO frequency is 400 MHz.
This field is wider than the RCC register SYSDIV field in order to provide
additional divisor values. This permits the system clock to be run at
much lower frequencies during Deep Sleep mode. For example, where
the RCC register SYSDIV encoding of 1111 provides /16, the RCC2
register SYSDIV2 encoding of 111111 provides /64.
22:14
reserved
RO
0x0
13
PWRDN2
R/W
1
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Power-Down PLL
When set, powers down the PLL.
12
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
11
BYPASS2
R/W
1
Bypass PLL
When set, bypasses the PLL for the clock source.
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October 09, 2007
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LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
Description
10:7
reserved
RO
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6:4
OSCSRC2
R/W
0x0
System Clock Source
Value Description
3:0
reserved
RO
0
0x0
Main oscillator (MOSC)
0x1
Internal oscillator (IOSC)
0x2
Internal oscillator / 4
0x3
30 kHz internal oscillator
0x7
32 kHz external oscillator
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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Preliminary
System Control
Register 11: Deep Sleep Clock Configuration (DSLPCLKCFG), offset 0x144
This register provides configuration information for the hardware control of Deep Sleep Mode.
Deep Sleep Clock Configuration (DSLPCLKCFG)
Base 0x400F.E000
Offset 0x144
Type R/W, reset 0x0780.0000
31
30
29
28
27
26
reserved
Type
Reset
25
24
23
22
21
20
DSDIVORIDE
18
17
16
reserved
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
19
RO
0
DSOSCSRC
Bit/Field
Name
Type
Reset
31:29
reserved
RO
0x0
28:23
DSDIVORIDE
R/W
0x0F
R/W
0
reserved
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Divider Field Override
6-bit system divider field to override when Deep-Sleep occurs with PLL
running.
22:7
reserved
RO
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6:4
DSOSCSRC
R/W
0x0
Clock Source
When set, forces IOSC to be clock source during Deep Sleep mode.
Value Name
3:0
reserved
RO
0x0
Description
0x0
NOORIDE No override to the oscillator clock source is done
0x1
IOSC
Use internal 12 MHz oscillator as source
0x3
30kHz
Use 30 kHz internal oscillator
0x7
32kHz
Use 32 kHz external oscillator
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 12: Device Identification 1 (DID1), offset 0x004
This register identifies the device family, part number, temperature range, pin count, and package
type.
Device Identification 1 (DID1)
Base 0x400F.E000
Offset 0x004
Type RO, reset 31
30
29
28
27
26
RO
0
15
25
24
23
22
21
20
RO
0
RO
0
RO
1
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
1
14
13
12
11
10
9
8
7
6
5
4
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
VER
Type
Reset
FAM
PINCOUNT
Type
Reset
RO
0
RO
1
18
17
16
RO
1
RO
1
RO
0
RO
1
3
2
1
0
PARTNO
reserved
RO
0
19
TEMP
Bit/Field
Name
Type
Reset
31:28
VER
RO
0x1
RO
0
PKG
ROHS
RO
1
RO
1
QUAL
RO
-
RO
-
Description
DID1 Version
This field defines the DID1 register format version. The version number
is numeric. The value of the VER field is encoded as follows (all other
encodings are reserved):
Value Description
0x1
27:24
FAM
RO
0x0
First revision of the DID1 register format, indicating a Stellaris
Fury-class device.
Family
This field provides the family identification of the device within the
Luminary Micro product portfolio. The value is encoded as follows (all
other encodings are reserved):
Value Description
0x0
23:16
PARTNO
RO
0xDD
Stellaris family of microcontollers, that is, all devices with
external part numbers starting with LM3S.
Part Number
This field provides the part number of the device within the family. The
value is encoded as follows (all other encodings are reserved):
Value Description
0xDD LM3S1911
15:13
PINCOUNT
RO
0x2
Package Pin Count
This field specifies the number of pins on the device package. The value
is encoded as follows (all other encodings are reserved):
Value Description
0x2
100-pin package
October 09, 2007
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Preliminary
System Control
Bit/Field
Name
Type
Reset
12:8
reserved
RO
0
7:5
TEMP
RO
0x1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Temperature Range
This field specifies the temperature rating of the device. The value is
encoded as follows (all other encodings are reserved):
Value Description
0x1
4:3
PKG
RO
0x1
Industrial temperature range (-40°C to 85°C)
Package Type
This field specifies the package type. The value is encoded as follows
(all other encodings are reserved):
Value Description
0x1
2
ROHS
RO
1
LQFP package
RoHS-Compliance
This bit specifies whether the device is RoHS-compliant. A 1 indicates
the part is RoHS-compliant.
1:0
QUAL
RO
-
Qualification Status
This field specifies the qualification status of the device. The value is
encoded as follows (all other encodings are reserved):
Value Description
0x0
Engineering Sample (unqualified)
0x1
Pilot Production (unqualified)
0x2
Fully Qualified
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 13: Device Capabilities 0 (DC0), offset 0x008
This register is predefined by the part and can be used to verify features.
Device Capabilities 0 (DC0)
Base 0x400F.E000
Offset 0x008
Type RO, reset 0x00FF.007F
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
7
6
5
4
3
2
1
0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
SRAMSZ
Type
Reset
FLASHSZ
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
Description
31:16
SRAMSZ
RO
0x00FF
SRAM Size
Indicates the size of the on-chip SRAM memory.
Value
Description
0x00FF 64 KB of SRAM
15:0
FLASHSZ
RO
0x007F
Flash Size
Indicates the size of the on-chip flash memory.
Value
Description
0x007F 256 KB of Flash
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Preliminary
System Control
Register 14: Device Capabilities 1 (DC1), offset 0x010
This register provides a list of features available in the system. The Stellaris family uses this register
format to indicate the availability of the following family features in the specific device: CANs, PWM,
ADC, Watchdog timer, Hibernation module, and debug capabilities. This register also indicates the
maximum clock frequency and maximum ADC sample rate. The format of this register is consistent
with the RCGC0, SCGC0, and DCGC0 clock control registers and the SRCR0 software reset control
register.
Device Capabilities 1 (DC1)
Base 0x400F.E000
Offset 0x010
Type RO, reset 0x0000.30DF
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
1
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
MPU
HIB
reserved
PLL
WDT
SWO
SWD
JTAG
RO
1
RO
1
RO
0
RO
1
RO
1
RO
1
RO
1
RO
1
reserved
Type
Reset
MINSYSDIV
Type
Reset
RO
1
reserved
Bit/Field
Name
Type
Reset
31:16
reserved
RO
0
15:12
MINSYSDIV
RO
0x3
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
System Clock Divider
Minimum 4-bit divider value for system clock. The reset value is
hardware-dependent. See the RCC register for how to change the
system clock divisor using the SYSDIV bit.
Value Description
0x3
Specifies a 50-MHz CPU clock with a PLL divider of 4.
11:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
MPU
RO
1
MPU Present
When set, indicates that the Cortex-M3 Memory Protection Unit (MPU)
module is present. See the ARM Cortex-M3 Technical Reference Manual
for details on the MPU.
6
HIB
RO
1
Hibernation Module Present
When set, indicates that the Hibernation module is present.
5
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
4
PLL
RO
1
PLL Present
When set, indicates that the on-chip Phase Locked Loop (PLL) is
present.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
3
WDT
RO
1
Description
Watchdog Timer Present
When set, indicates that a watchdog timer is present.
2
SWO
RO
1
SWO Trace Port Present
When set, indicates that the Serial Wire Output (SWO) trace port is
present.
1
SWD
RO
1
SWD Present
When set, indicates that the Serial Wire Debugger (SWD) is present.
0
JTAG
RO
1
JTAG Present
When set, indicates that the JTAG debugger interface is present.
October 09, 2007
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Preliminary
System Control
Register 15: Device Capabilities 2 (DC2), offset 0x014
This register provides a list of features available in the system. The Stellaris family uses this register
format to indicate the availability of the following family features in the specific device: Analog
Comparators, General-Purpose Timers, I2Cs, QEIs, SSIs, and UARTs. The format of this register
is consistent with the RCGC1, SCGC1, and DCGC1 clock control registers and the SRCR1 software
reset control register.
Device Capabilities 2 (DC2)
Base 0x400F.E000
Offset 0x014
Type RO, reset 0x030F.5037
31
30
29
RO
0
RO
0
RO
0
15
14
reserved
RO
0
28
27
26
25
24
RO
0
RO
0
RO
0
COMP1
COMP0
RO
1
13
12
11
10
9
I2C1
reserved
I2C0
RO
1
RO
0
RO
1
RO
0
RO
0
RO
0
reserved
Type
Reset
Type
Reset
23
22
21
20
19
18
17
16
RO
1
RO
0
RO
0
RO
0
RO
0
TIMER3
TIMER2
TIMER1
TIMER0
RO
1
RO
1
RO
1
RO
1
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
SSI1
SSI0
reserved
UART2
UART1
UART0
RO
1
RO
1
RO
0
RO
1
RO
1
RO
1
reserved
reserved
Bit/Field
Name
Type
Reset
Description
31:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
COMP1
RO
1
Analog Comparator 1 Present
When set, indicates that analog comparator 1 is present.
24
COMP0
RO
1
Analog Comparator 0 Present
When set, indicates that analog comparator 0 is present.
23:20
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
19
TIMER3
RO
1
Timer 3 Present
When set, indicates that General-Purpose Timer module 3 is present.
18
TIMER2
RO
1
Timer 2 Present
When set, indicates that General-Purpose Timer module 2 is present.
17
TIMER1
RO
1
Timer 1 Present
When set, indicates that General-Purpose Timer module 1 is present.
16
TIMER0
RO
1
Timer 0 Present
When set, indicates that General-Purpose Timer module 0 is present.
15
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
14
I2C1
RO
1
I2C Module 1 Present
When set, indicates that I2C module 1 is present.
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LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
Description
13
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
12
I2C0
RO
1
I2C Module 0 Present
When set, indicates that I2C module 0 is present.
11:6
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
SSI1
RO
1
SSI1 Present
When set, indicates that SSI module 1 is present.
4
SSI0
RO
1
SSI0 Present
When set, indicates that SSI module 0 is present.
3
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
2
UART2
RO
1
UART2 Present
When set, indicates that UART module 2 is present.
1
UART1
RO
1
UART1 Present
When set, indicates that UART module 1 is present.
0
UART0
RO
1
UART0 Present
When set, indicates that UART module 0 is present.
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System Control
Register 16: Device Capabilities 3 (DC3), offset 0x018
This register provides a list of features available in the system. The Stellaris family uses this register
format to indicate the availability of the following family features in the specific device: Analog
Comparator I/Os, CCP I/Os, ADC I/Os, and PWM I/Os.
Device Capabilities 3 (DC3)
Base 0x400F.E000
Offset 0x018
Type RO, reset 0x3F00.0FC0
31
30
reserved
Type
Reset
29
28
27
26
25
24
22
21
20
19
18
17
16
CCP5
CCP4
CCP3
CCP2
CCP1
CCP0
RO
0
RO
0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
23
RO
0
C1O
RO
0
RO
1
C1PLUS C1MINUS
RO
1
RO
1
C0O
RO
1
reserved
C0PLUS C0MINUS
RO
1
RO
1
reserved
Bit/Field
Name
Type
Reset
Description
31:30
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
29
CCP5
RO
1
CCP5 Pin Present
When set, indicates that Capture/Compare/PWM pin 5 is present.
28
CCP4
RO
1
CCP4 Pin Present
When set, indicates that Capture/Compare/PWM pin 4 is present.
27
CCP3
RO
1
CCP3 Pin Present
When set, indicates that Capture/Compare/PWM pin 3 is present.
26
CCP2
RO
1
CCP2 Pin Present
When set, indicates that Capture/Compare/PWM pin 2 is present.
25
CCP1
RO
1
CCP1 Pin Present
When set, indicates that Capture/Compare/PWM pin 1 is present.
24
CCP0
RO
1
CCP0 Pin Present
When set, indicates that Capture/Compare/PWM pin 0 is present.
23:12
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
11
C1O
RO
1
C1o Pin Present
When set, indicates that the analog comparator 1 output pin is present.
10
C1PLUS
RO
1
C1+ Pin Present
When set, indicates that the analog comparator 1 (+) input pin is present.
84
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
9
C1MINUS
RO
1
Description
C1- Pin Present
When set, indicates that the analog comparator 1 (-) input pin is present.
8
C0O
RO
1
C0o Pin Present
When set, indicates that the analog comparator 0 output pin is present.
7
C0PLUS
RO
1
C0+ Pin Present
When set, indicates that the analog comparator 0 (+) input pin is present.
6
C0MINUS
RO
1
C0- Pin Present
When set, indicates that the analog comparator 0 (-) input pin is present.
5:0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
85
Preliminary
System Control
Register 17: Device Capabilities 4 (DC4), offset 0x01C
This register provides a list of features available in the system. The Stellaris family uses this register
format to indicate the availability of the following family features in the specific device: Ethernet MAC
and PHY, GPIOs, and CCP I/Os. The format of this register is consistent with the RCGC2, SCGC2,
and DCGC2 clock control registers and the SRCR2 software reset control register.
Device Capabilities 4 (DC4)
Base 0x400F.E000
Offset 0x01C
Type RO, reset 0x0000.C0FF
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
CCP7
CCP6
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
reserved
Type
Reset
Type
Reset
reserved
RO
0
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15
CCP7
RO
1
CCP7 Pin Present
When set, indicates that Capture/Compare/PWM pin 7 is present.
14
CCP6
RO
1
CCP6 Pin Present
When set, indicates that Capture/Compare/PWM pin 6 is present.
13:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
GPIOH
RO
1
GPIO Port H Present
When set, indicates that GPIO Port H is present.
6
GPIOG
RO
1
GPIO Port G Present
When set, indicates that GPIO Port G is present.
5
GPIOF
RO
1
GPIO Port F Present
When set, indicates that GPIO Port F is present.
4
GPIOE
RO
1
GPIO Port E Present
When set, indicates that GPIO Port E is present.
3
GPIOD
RO
1
GPIO Port D Present
When set, indicates that GPIO Port D is present.
2
GPIOC
RO
1
GPIO Port C Present
When set, indicates that GPIO Port C is present.
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October 09, 2007
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LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
1
GPIOB
RO
1
Description
GPIO Port B Present
When set, indicates that GPIO Port B is present.
0
GPIOA
RO
1
GPIO Port A Present
When set, indicates that GPIO Port A is present.
October 09, 2007
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Preliminary
System Control
Register 18: Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100
This register controls 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
specifies that the system uses sleep modes.
Run Mode Clock Gating Control Register 0 (RCGC0)
Base 0x400F.E000
Offset 0x100
Type R/W, reset 0x00000040
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
HIB
reserved
RO
0
RO
0
WDT
R/W
0
reserved
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
HIB
R/W
0
HIB Clock Gating Control
This bit controls the clock gating for the Hibernation module. If set, the
unit receives a clock and functions. Otherwise, the unit is unclocked and
disabled.
5:4
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
WDT
R/W
0
WDT Clock Gating Control
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. If the unit is unclocked, a read or write to the unit generates
a bus fault.
2:0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 19: Sleep Mode Clock Gating Control Register 0 (SCGC0), offset
0x110
This register controls 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
specifies that the system uses sleep modes.
Sleep Mode Clock Gating Control Register 0 (SCGC0)
Base 0x400F.E000
Offset 0x110
Type R/W, reset 0x00000040
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
6
5
4
3
2
1
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
15
14
13
12
RO
0
RO
0
RO
0
RO
0
RO
0
11
10
9
8
7
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
HIB
RO
0
RO
0
RO
0
RO
0
R/W
0
reserved
RO
0
RO
0
WDT
R/W
0
reserved
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
HIB
R/W
0
HIB Clock Gating Control
This bit controls the clock gating for the Hibernation module. If set, the
unit receives a clock and functions. Otherwise, the unit is unclocked and
disabled.
5:4
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
WDT
R/W
0
WDT Clock Gating Control
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. If the unit is unclocked, a read or write to the unit generates
a bus fault.
2:0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
89
Preliminary
System Control
Register 20: Deep Sleep Mode Clock Gating Control Register 0 (DCGC0),
offset 0x120
This register controls 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
specifies that the system uses sleep modes.
Deep Sleep Mode Clock Gating Control Register 0 (DCGC0)
Base 0x400F.E000
Offset 0x120
Type R/W, reset 0x00000040
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
6
5
4
3
2
1
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
15
14
13
12
RO
0
RO
0
RO
0
RO
0
RO
0
11
10
9
8
7
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
HIB
RO
0
RO
0
RO
0
RO
0
R/W
0
reserved
RO
0
RO
0
WDT
R/W
0
reserved
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
HIB
R/W
0
HIB Clock Gating Control
This bit controls the clock gating for the Hibernation module. If set, the
unit receives a clock and functions. Otherwise, the unit is unclocked and
disabled.
5:4
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
WDT
R/W
0
WDT Clock Gating Control
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. If the unit is unclocked, a read or write to the unit generates
a bus fault.
2:0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 21: Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104
This register controls 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
specifies that the system uses sleep modes.
Run Mode Clock Gating Control Register 1 (RCGC1)
Base 0x400F.E000
Offset 0x104
Type R/W, reset 0x00000000
31
30
29
RO
0
RO
0
RO
0
15
14
reserved
RO
0
28
27
26
25
24
RO
0
RO
0
RO
0
COMP1
COMP0
R/W
0
13
12
11
10
9
I2C1
reserved
I2C0
R/W
0
RO
0
R/W
0
RO
0
RO
0
RO
0
reserved
Type
Reset
Type
Reset
23
22
21
20
19
18
17
16
R/W
0
RO
0
RO
0
RO
0
RO
0
TIMER3
TIMER2
TIMER1
TIMER0
R/W
0
R/W
0
R/W
0
R/W
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
reserved
reserved
Bit/Field
Name
Type
Reset
Description
31:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
COMP1
R/W
0
Analog Comparator 1 Clock Gating
This bit controls the clock gating for analog comparator 1. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
24
COMP0
R/W
0
Analog Comparator 0 Clock Gating
This bit controls the clock gating for analog comparator 0. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
23:20
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
19
TIMER3
R/W
0
Timer 3 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 3.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
October 09, 2007
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Preliminary
System Control
Bit/Field
Name
Type
Reset
18
TIMER2
R/W
0
Description
Timer 2 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 2.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
17
TIMER1
R/W
0
Timer 1 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 1.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
16
TIMER0
R/W
0
Timer 0 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 0.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
15
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
14
I2C1
R/W
0
I2C1 Clock Gating Control
This bit controls the clock gating for I2C module 1. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
13
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
12
I2C0
R/W
0
I2C0 Clock Gating Control
This bit controls the clock gating for I2C module 0. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
11:6
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
SSI1
R/W
0
SSI1 Clock Gating Control
This bit controls the clock gating for SSI module 1. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
4
SSI0
R/W
0
SSI0 Clock Gating Control
This bit controls the clock gating for SSI module 0. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
3
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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October 09, 2007
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LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
2
UART2
R/W
0
Description
UART2 Clock Gating Control
This bit controls the clock gating for UART module 2. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
1
UART1
R/W
0
UART1 Clock Gating Control
This bit controls the clock gating for UART module 1. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
0
UART0
R/W
0
UART0 Clock Gating Control
This bit controls the clock gating for UART module 0. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
October 09, 2007
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Preliminary
System Control
Register 22: Sleep Mode Clock Gating Control Register 1 (SCGC1), offset
0x114
This register controls 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
specifies that the system uses sleep modes.
Sleep Mode Clock Gating Control Register 1 (SCGC1)
Base 0x400F.E000
Offset 0x114
Type R/W, reset 0x00000000
31
30
29
28
27
26
reserved
Type
Reset
RO
0
RO
0
RO
0
24
COMP0
23
22
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
11
10
9
8
7
6
15
14
13
12
I2C1
reserved
I2C0
RO
0
R/W
0
RO
0
R/W
0
reserved
RO
0
RO
0
RO
0
RO
0
21
20
reserved
RO
0
reserved
Type
Reset
25
COMP1
RO
0
RO
0
RO
0
RO
0
19
18
17
16
TIMER3
TIMER2
TIMER1
TIMER0
R/W
0
R/W
0
R/W
0
R/W
0
5
4
3
2
1
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
COMP1
R/W
0
Analog Comparator 1 Clock Gating
This bit controls the clock gating for analog comparator 1. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
24
COMP0
R/W
0
Analog Comparator 0 Clock Gating
This bit controls the clock gating for analog comparator 0. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
23:20
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
19
TIMER3
R/W
0
Timer 3 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 3.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
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LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
18
TIMER2
R/W
0
Description
Timer 2 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 2.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
17
TIMER1
R/W
0
Timer 1 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 1.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
16
TIMER0
R/W
0
Timer 0 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 0.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
15
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
14
I2C1
R/W
0
I2C1 Clock Gating Control
This bit controls the clock gating for I2C module 1. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
13
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
12
I2C0
R/W
0
I2C0 Clock Gating Control
This bit controls the clock gating for I2C module 0. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
11:6
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
SSI1
R/W
0
SSI1 Clock Gating Control
This bit controls the clock gating for SSI module 1. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
4
SSI0
R/W
0
SSI0 Clock Gating Control
This bit controls the clock gating for SSI module 0. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
3
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
95
Preliminary
System Control
Bit/Field
Name
Type
Reset
2
UART2
R/W
0
Description
UART2 Clock Gating Control
This bit controls the clock gating for UART module 2. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
1
UART1
R/W
0
UART1 Clock Gating Control
This bit controls the clock gating for UART module 1. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
0
UART0
R/W
0
UART0 Clock Gating Control
This bit controls the clock gating for UART module 0. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 23: Deep Sleep Mode Clock Gating Control Register 1 (DCGC1),
offset 0x124
This register controls 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
specifies that the system uses sleep modes.
Deep Sleep Mode Clock Gating Control Register 1 (DCGC1)
Base 0x400F.E000
Offset 0x124
Type R/W, reset 0x00000000
31
30
29
28
27
26
reserved
Type
Reset
RO
0
RO
0
RO
0
24
COMP0
23
22
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
11
10
9
8
7
6
15
14
13
12
I2C1
reserved
I2C0
RO
0
R/W
0
RO
0
R/W
0
reserved
RO
0
RO
0
RO
0
RO
0
21
20
reserved
RO
0
reserved
Type
Reset
25
COMP1
RO
0
RO
0
RO
0
RO
0
19
18
17
16
TIMER3
TIMER2
TIMER1
TIMER0
R/W
0
R/W
0
R/W
0
R/W
0
5
4
3
2
1
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
COMP1
R/W
0
Analog Comparator 1 Clock Gating
This bit controls the clock gating for analog comparator 1. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
24
COMP0
R/W
0
Analog Comparator 0 Clock Gating
This bit controls the clock gating for analog comparator 0. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
23:20
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
19
TIMER3
R/W
0
Timer 3 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 3.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
October 09, 2007
97
Preliminary
System Control
Bit/Field
Name
Type
Reset
18
TIMER2
R/W
0
Description
Timer 2 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 2.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
17
TIMER1
R/W
0
Timer 1 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 1.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
16
TIMER0
R/W
0
Timer 0 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 0.
If set, the unit receives a clock and functions. Otherwise, the unit is
unclocked and disabled. If the unit is unclocked, reads or writes to the
unit will generate a bus fault.
15
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
14
I2C1
R/W
0
I2C1 Clock Gating Control
This bit controls the clock gating for I2C module 1. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
13
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
12
I2C0
R/W
0
I2C0 Clock Gating Control
This bit controls the clock gating for I2C module 0. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
11:6
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
SSI1
R/W
0
SSI1 Clock Gating Control
This bit controls the clock gating for SSI module 1. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
4
SSI0
R/W
0
SSI0 Clock Gating Control
This bit controls the clock gating for SSI module 0. If set, the unit receives
a clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
3
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
2
UART2
R/W
0
Description
UART2 Clock Gating Control
This bit controls the clock gating for UART module 2. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
1
UART1
R/W
0
UART1 Clock Gating Control
This bit controls the clock gating for UART module 1. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
0
UART0
R/W
0
UART0 Clock Gating Control
This bit controls the clock gating for UART module 0. If set, the unit
receives a clock and functions. Otherwise, the unit is unclocked and
disabled. If the unit is unclocked, reads or writes to the unit will generate
a bus fault.
October 09, 2007
99
Preliminary
System Control
Register 24: Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108
This register controls 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
specifies that the system uses sleep modes.
Run Mode Clock Gating Control Register 2 (RCGC2)
Base 0x400F.E000
Offset 0x108
Type R/W, reset 0x00000000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
GPIOH
R/W
0
Port H Clock Gating Control
This bit controls the clock gating for Port H. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
6
GPIOG
R/W
0
Port G Clock Gating Control
This bit controls the clock gating for Port G. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
5
GPIOF
R/W
0
Port F Clock Gating Control
This bit controls the clock gating for Port F. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
4
GPIOE
R/W
0
Port E Clock Gating Control
This bit controls the clock gating for Port E. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
100
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
3
GPIOD
R/W
0
Description
Port D Clock Gating Control
This bit controls the clock gating for Port D. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
2
GPIOC
R/W
0
Port C Clock Gating Control
This bit controls the clock gating for Port C. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
1
GPIOB
R/W
0
Port B Clock Gating Control
This bit controls the clock gating for Port B. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
0
GPIOA
R/W
0
Port A Clock Gating Control
This bit controls the clock gating for Port A. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
October 09, 2007
101
Preliminary
System Control
Register 25: Sleep Mode Clock Gating Control Register 2 (SCGC2), offset
0x118
This register controls 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
specifies that the system uses sleep modes.
Sleep Mode Clock Gating Control Register 2 (SCGC2)
Base 0x400F.E000
Offset 0x118
Type R/W, reset 0x00000000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
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
Name
Type
Reset
Description
31:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
GPIOH
R/W
0
Port H Clock Gating Control
This bit controls the clock gating for Port H. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
6
GPIOG
R/W
0
Port G Clock Gating Control
This bit controls the clock gating for Port G. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
5
GPIOF
R/W
0
Port F Clock Gating Control
This bit controls the clock gating for Port F. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
4
GPIOE
R/W
0
Port E Clock Gating Control
This bit controls the clock gating for Port E. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
3
GPIOD
R/W
0
Description
Port D Clock Gating Control
This bit controls the clock gating for Port D. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
2
GPIOC
R/W
0
Port C Clock Gating Control
This bit controls the clock gating for Port C. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
1
GPIOB
R/W
0
Port B Clock Gating Control
This bit controls the clock gating for Port B. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
0
GPIOA
R/W
0
Port A Clock Gating Control
This bit controls the clock gating for Port A. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
October 09, 2007
103
Preliminary
System Control
Register 26: Deep Sleep Mode Clock Gating Control Register 2 (DCGC2),
offset 0x128
This register controls 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
specifies that the system uses sleep modes.
Deep Sleep Mode Clock Gating Control Register 2 (DCGC2)
Base 0x400F.E000
Offset 0x128
Type R/W, reset 0x00000000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
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
Name
Type
Reset
Description
31:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
GPIOH
R/W
0
Port H Clock Gating Control
This bit controls the clock gating for Port H. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
6
GPIOG
R/W
0
Port G Clock Gating Control
This bit controls the clock gating for Port G. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
5
GPIOF
R/W
0
Port F Clock Gating Control
This bit controls the clock gating for Port F. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
4
GPIOE
R/W
0
Port E Clock Gating Control
This bit controls the clock gating for Port E. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
3
GPIOD
R/W
0
Description
Port D Clock Gating Control
This bit controls the clock gating for Port D. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
2
GPIOC
R/W
0
Port C Clock Gating Control
This bit controls the clock gating for Port C. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
1
GPIOB
R/W
0
Port B Clock Gating Control
This bit controls the clock gating for Port B. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
0
GPIOA
R/W
0
Port A Clock Gating Control
This bit controls the clock gating for Port A. If set, the unit receives a
clock and functions. Otherwise, the unit is unclocked and disabled. If
the unit is unclocked, reads or writes to the unit will generate a bus fault.
October 09, 2007
105
Preliminary
System Control
Register 27: Software Reset Control 0 (SRCR0), offset 0x040
Writes to this register are masked by the bits in the Device Capabilities 1 (DC1) register.
Software Reset Control 0 (SRCR0)
Base 0x400F.E000
Offset 0x040
Type R/W, reset 0x00000000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
HIB
reserved
RO
0
RO
0
WDT
R/W
0
reserved
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
HIB
R/W
0
HIB Reset Control
Reset control for the Hibernation module.
5:4
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
WDT
R/W
0
WDT Reset Control
Reset control for Watchdog unit.
2:0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
106
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 28: Software Reset Control 1 (SRCR1), offset 0x044
Writes to this register are masked by the bits in the Device Capabilities 2 (DC2) register.
Software Reset Control 1 (SRCR1)
Base 0x400F.E000
Offset 0x044
Type R/W, reset 0x00000000
31
30
29
RO
0
RO
0
RO
0
15
14
reserved
RO
0
28
27
26
25
24
RO
0
RO
0
RO
0
COMP1
COMP0
R/W
0
13
12
11
10
9
I2C1
reserved
I2C0
R/W
0
RO
0
R/W
0
RO
0
RO
0
RO
0
reserved
Type
Reset
Type
Reset
23
22
21
20
19
18
17
16
R/W
0
RO
0
RO
0
RO
0
RO
0
TIMER3
TIMER2
TIMER1
TIMER0
R/W
0
R/W
0
R/W
0
R/W
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
reserved
reserved
Bit/Field
Name
Type
Reset
Description
31:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
COMP1
R/W
0
Analog Comp 1 Reset Control
Reset control for analog comparator 1.
24
COMP0
R/W
0
Analog Comp 0 Reset Control
Reset control for analog comparator 0.
23:20
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
19
TIMER3
R/W
0
Timer 3 Reset Control
Reset control for General-Purpose Timer module 3.
18
TIMER2
R/W
0
Timer 2 Reset Control
Reset control for General-Purpose Timer module 2.
17
TIMER1
R/W
0
Timer 1 Reset Control
Reset control for General-Purpose Timer module 1.
16
TIMER0
R/W
0
Timer 0 Reset Control
Reset control for General-Purpose Timer module 0.
15
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
14
I2C1
R/W
0
I2C1 Reset Control
Reset control for I2C unit 1.
13
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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System Control
Bit/Field
Name
Type
Reset
12
I2C0
R/W
0
Description
I2C0 Reset Control
Reset control for I2C unit 0.
11:6
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
SSI1
R/W
0
SSI1 Reset Control
Reset control for SSI unit 1.
4
SSI0
R/W
0
SSI0 Reset Control
Reset control for SSI unit 0.
3
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
2
UART2
R/W
0
UART2 Reset Control
Reset control for UART unit 2.
1
UART1
R/W
0
UART1 Reset Control
Reset control for UART unit 1.
0
UART0
R/W
0
UART0 Reset Control
Reset control for UART unit 0.
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Register 29: Software Reset Control 2 (SRCR2), offset 0x048
Writes to this register are masked by the bits in the Device Capabilities 4 (DC4) register.
Software Reset Control 2 (SRCR2)
Base 0x400F.E000
Offset 0x048
Type R/W, reset 0x00000000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
GPIOH
R/W
0
Port H Reset Control
Reset control for GPIO Port H.
6
GPIOG
R/W
0
Port G Reset Control
Reset control for GPIO Port G.
5
GPIOF
R/W
0
Port F Reset Control
Reset control for GPIO Port F.
4
GPIOE
R/W
0
Port E Reset Control
Reset control for GPIO Port E.
3
GPIOD
R/W
0
Port D Reset Control
Reset control for GPIO Port D.
2
GPIOC
R/W
0
Port C Reset Control
Reset control for GPIO Port C.
1
GPIOB
R/W
0
Port B Reset Control
Reset control for GPIO Port B.
0
GPIOA
R/W
0
Port A Reset Control
Reset control for GPIO Port A.
October 09, 2007
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Hibernation Module
7
Hibernation Module
The Hibernation Module manages removal and restoration of power to the rest of the microcontroller
to provide a means for reducing power consumption. When the processor and peripherals are idle,
power can be completely removed with only the Hibernation Module remaining powered. Power
can be restored based on an external signal, or at a certain time using the built-in real-time clock
(RTC). The Hibernation module can be independently supplied from a battery or an auxillary power
supply.
The Hibernation module has the following features:
■ Power-switching logic to discrete external regulator
■ Dedicated pin for waking from an external signal
■ Low-battery detection, signalling, and interrupt generation
■ 32-bit real-time counter (RTC)
■ Two 32-bit RTC match registers for timed wake-up and interrupt generation
■ Clock source from a 32.768-kHz external oscillator or a 4.194304-MHz crystal
■ RTC predivider trim for making fine adjustments to the clock rate
■ 64 32-bit words of non-volatile memory
■ Programmable interrupts for RTC match, external wake, and low battery events
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7.1
Block Diagram
Figure 7-1. Hibernation Module Block Diagram
HIBCTL.CLK32EN
XOSC0
XOSC1
Interrupts
HIBIM
HIBRIS
HIBMIS
HIBIC
Pre-Divider
/128
HIBRTCT
HIBCTL.CLKSEL
Non-Volatile
Memory
HIBDATA
RTC
HIBRTCC
HIBRTCLD
HIBRTCM0
HIBRTCM1
WAKE
MATCH0/1
LOWBAT
VDD
Low Battery
Detect
VBAT
HIBCTL.LOWBATEN
7.2
Interrupts
to CPU
Power
Sequence
Logic
HIB
HIBCTL.PWRCUT
HIBCTL.RTCWEN
HIBCTL.EXTWEN
HIBCTL.VABORT
Functional Description
The Hibernation module controls the power to the processor with an enable signal (HIB) that signals
an external voltage regulator to turn off. The Hibernation module power is determined dynamically.
The supply voltage of the Hibernation module is the larger of the main voltage source (VDD) or the
battery/auxilliary voltage source (VBAT). A voting circuit indicates the larger and an internal power
switch selects the appropriate voltage source. The Hibernation module also has a separate clock
source to maintain a real-time clock (RTC). Once in hibernation, the module signals an external
voltage regulator to turn back on the power when an external pin (WAKE) is asserted, or when the
internal RTC reaches a certain value. The Hibernation module can also detect when the battery
voltage is low, and optionally prevent hibernation when this occurs.
Power-up from a power cut to code execution is defined as the regulator turn-on time (specifed at
tHIB_TO_VDD maximum) plus the normal chip POR (see “Hibernation Module” on page 398).
7.2.1
Register Access Timing
Because the Hibernation module has an independent clocking domain, certain registers must be
written only with a timing gap between accesses. The delay time is tHIB_REG_WRITE, therefore software
must guarantee that a delay of tHIB_REG_WRITE is inserted between back-to-back writes to certain
Hibernation registers, or between a write followed by a read to those same registers. There is no
October 09, 2007
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Hibernation Module
restriction on timing for back-to-back reads from the Hibernation module. Refer to “Register
Descriptions” on page 116 for details about which registers are subject to this timing restriction.
7.2.2
Clock Source
The Hibernation module must be clocked by an external source, even if the RTC feature will not be
used. An external oscillator or crystal can be used for this purpose. To use a crystal, a 4.194304-MHz
crystal is connected to the XOSC0 and XOSC1 pins. This clock signal is divided by 128 internally to
produce the 32.768-kHz clock reference. To use a more precise clock source, a 32.768-kHz oscillator
can be connected to the XOSC0 pin.
The clock source is enabled by setting the CLK32EN bit of the HIBCTL register. The type of clock
source is selected by setting the CLKSEL bit to 0 for a 4.194304-MHz clock source, and to 1 for a
32.768-kHz clock source. If the bit is set to 0, the input clock is divided by 128, resulting in a
32.768-kHz clock source. If a crystal is used for the clock source, the software must leave a delay
of tXOSC_SETTLE after setting the CLK32EN bit and before any other accesses to the Hibernation
module registers. The delay allows the crystal to power up and stabilize. If an oscillator is used for
the clock source, no delay is needed.
7.2.3
Battery Management
The Hibernation module can be independently powered by a battery or an auxiliary power source.
The module can monitor the voltage level of the battery and detect when the voltage becomes too
low. When this happens, an interrupt can be generated. The module can also be configured so that
it will not go into Hibernate mode if the battery voltage is too low.
Note that the Hibernation module draws power from whichever source (VBAT or VDD) has the higher
voltage. Therefore, it is important to design the circuit to ensure that VDD is higher that VBAT under
nominal conditions or else the Hibernation module draws power from the battery even when VDD
is available.
The Hibernation module can be configured to detect a low battery condition by setting the LOWBATEN
bit of the HIBCTL register. In this configuration, the LOWBAT bit of the HIBRIS register will be set
when the battery level is low. If the VABORT bit is also set, then the module is prevented from entering
Hibernation mode when a low battery is detected. The module can also be configured to generate
an interrupt for the low-battery condition (see “Interrupts and Status” on page 113).
7.2.4
Real-Time Clock
The Hibernation module includes a 32-bit counter that increments once per second with a proper
clock source and configuration (see “Clock Source” on page 112). The 32.768-kHz clock signal is
fed into a predivider register which counts down the 32.768-kHz clock ticks to achieve a once per
second clock rate for the RTC. The rate can be adjusted to compensate for inaccuracies in the clock
source by using the predivider trim register. This register has a nominal value of 0x7FFF, and is
used for one second out of every 64 seconds to divide the input clock. This allows the software to
make fine corrections to the clock rate by adjusting the predivider trim register up or down from
0x7FFF. The predivider trim should be adjusted up from 0x7FFF in order to slow down the RTC
rate, and down from 0x7FFF in order to speed up the RTC rate.
The Hibernation module includes two 32-bit match registers that are compared to the value of the
RTC counter. The match registers can be used to wake the processor from hibernation mode, or
to generate an interrupt to the processor if it is not in hibernation.
The RTC must be enabled with the RTCEN bit of the HIBCTL register. The value of the RTC can be
set at any time by writing to the HIBRTCLD register. The predivider trim can be adjusted by reading
and writing the HIBRTCT register. The predivider uses this register once every 64 seconds to adjust
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October 09, 2007
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LM3S1911 Microcontroller
the clock rate. The two match registers can be set by writing to the HIBRTCM0 and HIBRTCM1
registers. The RTC can be configured to generate interrupts by using the interrupt registers (see
“Interrupts and Status” on page 113).
7.2.5
Non-Volatile Memory
The Hibernation module contains 64 32-bit words of memory which are retained during hibernation.
This memory is powered from the battery or auxillary power supply during hibernation. The processor
software can save state information in this memory prior to hibernation, and can then recover the
state upon waking. The non-volatile memory can be accessed through the HIBDATA registers.
7.2.6
Power Control
The Hibernation module controls power to the processor through the use of the HIB pin, which is
intended to be connected to the enable signal of the external regulator(s) providing 3.3 V and/or
2.5 V to the microcontroller. When the HIB signal is asserted by the Hibernation module, the external
regulator is turned off and no longer powers the microcontroller. The Hibernation module remains
powered from the VBAT supply, which could be a battery or an auxillary power source. Hibernation
mode is initiated by the microcontroller setting the HIBREQ bit of the HIBCTL register. Prior to doing
this, a wake-up condition must be configured, either from the external WAKE pin, or by using an RTC
match.
The Hibernation module is configured to wake from the external WAKE pin by setting the PINWEN
bit of the HIBCTL register. It is configured to wake from RTC match by setting the RTCWEN bit. Either
one or both of these bits can be set prior to going into hibernation. The WAKE pin includes a weak
internal pull-up. Note that both the HIB and WAKE pins use the Hibernation module's internal power
supply as the logic 1 reference.
When the Hibernation module wakes, the microcontroller will see a normal power-on reset. It can
detect that the power-on was due to a wake from hibernation by examining the raw interrupt status
register (see “Interrupts and Status” on page 113) and by looking for state data in the non-volatile
memory (see “Non-Volatile Memory” on page 113).
When the HIB signal deasserts, enabling the external regulator, the external regulator must reach
the operating voltage within tHIB_TO_VDD.
7.2.7
Interrupts and Status
The Hibernation module can generate interrupts when the following conditions occur:
■ Assertion of WAKE pin
■ RTC match
■ Low battery detected
All of the interrupts are ORed together before being sent to the interrupt controller, so the Hibernate
module can only generate a single interrupt request to the controller at any given time. The software
interrupt handler can service multiple interrupt events by reading the HIBMIS register. Software can
also read the status of the Hibernation module at any time by reading the HIBRIS register which
shows all of the pending events. This register can be used at power-on to see if a wake condition
is pending, which indicates to the software that a hibernation wake occurred.
The events that can trigger an interrupt are configured by setting the appropriate bits in the HIBIM
register. Pending interrupts can be cleared by writing the corresponding bit in the HIBIC register.
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Hibernation Module
7.3
Initialization and Configuration
The Hibernation module can be configured in several different combinations. The following sections
show the recommended programming sequence for various scenarios. The examples below assume
that a 32.768-kHz oscillator is used, and thus always show bit 2 (CLKSEL) of the HIBCTL register
set to 1. If a 4.194304-MHz crystal is used instead, then the CLKSEL bit remains cleared. Because
the Hibernation module runs at 32 kHz and is asynchronous to the rest of the system, software must
allow a delay of tHIB_REG_WRITE after writes to certain registers (see “Register Access
Timing” on page 111). The registers that require a delay are denoted with a footnote in
Table 7-1 on page 115.
7.3.1
Initialization
The clock source must be enabled first, even if the RTC will not be used. If a 4.194304-MHz crystal
is used, perform the following steps:
1. Write 0x40 to the HIBCTL register at offset 0x10 to enable the crystal and select the divide-by-128
input path.
2. Wait for a time of tXOSC_SETTLE for the crystal to power up and stabilize before performing any
other operations with the Hibernation module.
If a 32.678-kHz oscillator is used, then perform the following steps:
1. Write 0x44 to the HIBCTL register at offset 0x10 to enable the oscillator input.
2. No delay is necessary.
The above is only necessary when the entire system is initialized for the first time. If the processor
is powered due to a wake from hibernation, then the Hibernation module has already been powered
up and the above steps are not necessary. The software can detect that the Hibernation module
and clock are already powered by examining the CLK32EN bit of the HIBCTL register.
7.3.2
RTC Match Functionality (No Hibernation)
The following steps are needed to use the RTC match functionality of the Hibernation module:
1. Write the required RTC match value to one of the HIBRTCMn registers at offset 0x004 or 0x008.
2. Write the required RTC load value to the HIBRTCLD register at offset 0x00C.
3. Set the required RTC match interrupt mask in the RTCALT0 and RTCALT1 bits (bits 1:0) in the
HIBIM register at offset 0x014.
4. Write 0x0000.0041 to the HIBCTL register at offset 0x010 to enable the RTC to begin counting.
7.3.3
RTC Match/Wake-Up from Hibernation
The following steps are needed to use the RTC match and wake-up functionality of the Hibernation
module:
1. Write the required RTC match value to the HIBRTCMn registers at offset 0x004 or 0x008.
2. Write the required RTC load value to the HIBRTCLD register at offset 0x00C.
3. Write any data to be retained during power cut to the HIBDATA register at offsets 0x030-0x12C.
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October 09, 2007
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LM3S1911 Microcontroller
4. Set the RTC Match Wake-Up and start the hibernation sequence by writing 0x0000.004F to the
HIBCTL register at offset 0x010.
7.3.4
External Wake-Up from Hibernation
The following steps are needed to use the Hibernation module with the external WAKE pin as the
wake-up source for the microcontroller:
1. Write any data to be retained during power cut to the HIBDATA register at offsets 0x030-0x12C.
2. Enable the external wake and start the hibernation sequence by writing 0x0000.0056 to the
HIBCTL register at offset 0x010.
7.3.5
RTC/External Wake-Up from Hibernation
1. Write the required RTC match value to the HIBRTCMn registers at offset 0x004 or 0x008.
2. Write the required RTC load value to the HIBRTCLD register at offset 0x00C.
3. Write any data to be retained during power cut to the HIBDATA register at offsets 0x030-0x12C.
4. Set the RTC Match/External Wake-Up and start the hibernation sequence by writing 0x0000.005F
to the HIBCTL register at offset 0x010.
7.4
Register Map
Table 7-1 on page 115 lists the Hibernation registers. All addresses given are relative to the Hibernation
Module base address at 0x400F.C000.
Note:
HIBRTCC, HIBRTCM0, HIBRTCM1, HIBRTCLD, HIBRTCT, and HIBDATA are on the
Hibernation module clock domain and require a delay of tHIB_REG_WRITE between write
accesses. See “Register Access Timing” on page 111.
Table 7-1. Hibernation Module Register Map
Offset
Name
0x000
Description
See
page
Type
Reset
HIBRTCC
RO
0x0000.0000
Hibernation RTC Counter
117
0x004
HIBRTCM0
R/W
0xFFFF.FFFF
Hibernation RTC Match 0
118
0x008
HIBRTCM1
R/W
0xFFFF.FFFF
Hibernation RTC Match 1
119
0x00C
HIBRTCLD
R/W
0xFFFF.FFFF
Hibernation RTC Load
120
0x010
HIBCTL
R/W
0x0000.0000
Hibernation Control
121
0x014
HIBIM
R/W
0x0000.0000
Hibernation Interrupt Mask
123
0x018
HIBRIS
RO
0x0000.0000
Hibernation Raw Interrupt Status
124
0x01C
HIBMIS
RO
0x0000.0000
Hibernation Masked Interrupt Status
125
0x020
HIBIC
R/W1C
0x0000.0000
Hibernation Interrupt Clear
126
0x024
HIBRTCT
R/W
0x0000.7FFF
Hibernation RTC Trim
127
0x0300x12C
HIBDATA
R/W
0x0000.0000
Hibernation Data
128
October 09, 2007
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Hibernation Module
7.5
Register Descriptions
The remainder of this section lists and describes the Hibernation module registers, in numerical
order by address offset.
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October 09, 2007
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LM3S1911 Microcontroller
Register 1: Hibernation RTC Counter (HIBRTCC), offset 0x000
This register is the current 32-bit value of the RTC counter.
Hibernation RTC Counter (HIBRTCC)
Base 0x400F.C000
Offset 0x000
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
RO
0
RTCC
Type
Reset
RTCC
Type
Reset
Bit/Field
Name
Type
31:0
RTCC
RO
Reset
Description
0x0000.0000 RTC Counter
A read returns the 32-bit counter value. This register is read-only. To
change the value, use the HIBRTCLD register.
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Register 2: Hibernation RTC Match 0 (HIBRTCM0), offset 0x004
This register is the 32-bit match 0 register for the RTC counter.
Hibernation RTC Match 0 (HIBRTCM0)
Base 0x400F.C000
Offset 0x004
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
R/W
1
R/W
1
R/W
1
RTCM0
Type
Reset
RTCM0
Type
Reset
Bit/Field
Name
Type
31:0
RTCM0
R/W
Reset
Description
0xFFFF.FFFF RTC Match 0
A write loads the value into the RTC match register.
A read returns the current match value.
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Register 3: Hibernation RTC Match 1 (HIBRTCM1), offset 0x008
This register is the 32-bit match 1 register for the RTC counter.
Hibernation RTC Match 1 (HIBRTCM1)
Base 0x400F.C000
Offset 0x008
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
R/W
1
R/W
1
R/W
1
RTCM1
Type
Reset
RTCM1
Type
Reset
Bit/Field
Name
Type
31:0
RTCM1
R/W
Reset
Description
0xFFFF.FFFF RTC Match 1
A write loads the value into the RTC match register.
A read returns the current match value.
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Hibernation Module
Register 4: Hibernation RTC Load (HIBRTCLD), offset 0x00C
This register is the 32-bit value loaded into the RTC counter.
Hibernation RTC Load (HIBRTCLD)
Base 0x400F.C000
Offset 0x00C
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
R/W
1
R/W
1
R/W
1
RTCLD
Type
Reset
RTCLD
Type
Reset
Bit/Field
Name
Type
31:0
RTCLD
R/W
Reset
Description
0xFFFF.FFFF RTC Load
A write loads the current value into the RTC counter (RTCC).
A read returns the 32-bit load value.
120
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LM3S1911 Microcontroller
Register 5: Hibernation Control (HIBCTL), offset 0x010
This register is the control register for the Hibernation module.
Hibernation Control (HIBCTL)
Base 0x400F.C000
Offset 0x010
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
reserved
Type
Reset
reserved
Type
Reset
VABORT CLK32EN LOWBATEN PINWEN RTCWEN CLKSEL HIBREQ
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
RTCEN
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
VABORT
R/W
0
Power Cut Abort Enable
0: Power cut occurs during a low-battery alert
1: Power cut is aborted
6
CLK32EN
R/W
0
32-kHz Oscillator Enable
0: Disabled
1: Enabled
This bit must be enabled to use the Hibernation module. If a crystal is
used, then software should wait 20 ms after setting this bit to allow the
crystal to power up and stabilize.
5
LOWBATEN
R/W
0
Low Battery Monitoring Enable
0: Disabled
1: Enabled
When set, low battery voltage detection is enabled.
4
PINWEN
R/W
0
External WAKE Pin Enable
0: Disabled
1: Enabled
When set, an external event on the WAKE pin will re-power the device.
3
RTCWEN
R/W
0
RTC Wake-up Enable
0: Disabled
1: Enabled
When set, an RTC match event (RTCM0 or RTCM1) will re-power the
device based on the RTC counter value matching the corresponding
match register 0 or 1.
October 09, 2007
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Preliminary
Hibernation Module
Bit/Field
Name
Type
Reset
2
CLKSEL
R/W
0
Description
Hibernation Module Clock Select
0: Use Divide by 128 output. Use this value for a 4-MHz crystal.
1: Use raw output. Use this value for a 32-kHz oscillator.
1
HIBREQ
R/W
0
Hibernation Request
0: Disabled
1: Hibernation initiated
After a wake-up event, this bit is cleared by hardware.
0
RTCEN
R/W
0
RTC Timer Enable
0: Disabled
1: Enabled
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LM3S1911 Microcontroller
Register 6: Hibernation Interrupt Mask (HIBIM), offset 0x014
This register is the interrupt mask register for the Hibernation module interrupt sources.
Hibernation Interrupt Mask (HIBIM)
Base 0x400F.C000
Offset 0x014
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
EXTW
Bit/Field
Name
Type
Reset
31:4
reserved
RO
0x000.0000
3
EXTW
R/W
0
R/W
0
LOWBAT RTCALT1 RTCALT0
R/W
0
R/W
0
R/W
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
External Wake-Up Interrupt Mask
0: Masked
1: Unmasked
2
LOWBAT
R/W
0
Low Battery Voltage Interrupt Mask
0: Masked
1: Unmasked
1
RTCALT1
R/W
0
RTC Alert1 Interrupt Mask
0: Masked
1: Unmasked
0
RTCALT0
R/W
0
RTC Alert0 Interrupt Mask
0: Masked
1: Unmasked
October 09, 2007
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Hibernation Module
Register 7: Hibernation Raw Interrupt Status (HIBRIS), offset 0x018
This register is the raw interrupt status for the Hibernation module interrupt sources.
Hibernation Raw Interrupt Status (HIBRIS)
Base 0x400F.C000
Offset 0x018
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
EXTW
RO
0
Bit/Field
Name
Type
Reset
31:4
reserved
RO
0x000.0000
3
EXTW
RO
0
External Wake-Up Raw Interrupt Status
2
LOWBAT
RO
0
Low Battery Voltage Raw Interrupt Status
1
RTCALT1
RO
0
RTC Alert1 Raw Interrupt Status
0
RTCALT0
RO
0
RTC Alert0 Raw Interrupt Status
LOWBAT RTCALT1 RTCALT0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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LM3S1911 Microcontroller
Register 8: Hibernation Masked Interrupt Status (HIBMIS), offset 0x01C
This register is the masked interrupt status for the Hibernation module interrupt sources.
Hibernation Masked Interrupt Status (HIBMIS)
Base 0x400F.C000
Offset 0x01C
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
EXTW
RO
0
Bit/Field
Name
Type
Reset
31:4
reserved
RO
0x000.0000
3
EXTW
RO
0
External Wake-Up Masked Interrupt Status
2
LOWBAT
RO
0
Low Battery Voltage Masked Interrupt Status
1
RTCALT1
RO
0
RTC Alert1 Masked Interrupt Status
0
RTCALT0
RO
0
RTC Alert0 Masked Interrupt Status
LOWBAT RTCALT1 RTCALT0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
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Preliminary
Hibernation Module
Register 9: Hibernation Interrupt Clear (HIBIC), offset 0x020
This register is the interrupt write-one-to-clear register for the Hibernation module interrupt sources.
Hibernation Interrupt Clear (HIBIC)
Base 0x400F.C000
Offset 0x020
Type R/W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W1C
0
reserved
Type
Reset
reserved
Type
Reset
EXTW
Bit/Field
Name
Type
Reset
31:4
reserved
RO
0x000.0000
3
EXTW
R/W1C
0
LOWBAT RTCALT1 RTCALT0
R/W1C
0
R/W1C
0
R/W1C
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
External Wake-Up Masked Interrupt Clear
Reads return an indeterminate value.
2
LOWBAT
R/W1C
0
Low Battery Voltage Masked Interrupt Clear
Reads return an indeterminate value.
1
RTCALT1
R/W1C
0
RTC Alert1 Masked Interrupt Clear
Reads return an indeterminate value.
0
RTCALT0
R/W1C
0
RTC Alert0 Masked Interrupt Clear
Reads return an indeterminate value.
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October 09, 2007
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LM3S1911 Microcontroller
Register 10: Hibernation RTC Trim (HIBRTCT), offset 0x024
This register contains the value that is used to trim the RTC clock predivider. It represents the
computed underflow value that is used during the trim cycle. It is represented as 0x7FFF ± N clock
cycles.
Hibernation RTC Trim (HIBRTCT)
Base 0x400F.C000
Offset 0x024
Type R/W, reset 0x0000.7FFF
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
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
reserved
Type
Reset
TRIM
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15:0
TRIM
R/W
0x7FFF
RTC Trim Value
This value is loaded into the RTC predivider every 64 seconds. It is used
to adjust the RTC rate to account for drift and inaccuracy in the clock
source. The compensation is made by software by adjusting the default
value of 0x7FFF up or down.
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Preliminary
Hibernation Module
Register 11: Hibernation Data (HIBDATA), offset 0x030-0x12C
This address space is implemented as a 64x32-bit memory (256 bytes). It can be loaded by the
system processor in order to store any non-volatile state data and will not lose power during a power
cut operation.
Hibernation Data (HIBDATA)
Base 0x400F.C000
Offset 0x030-0x12C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
R/W
0
RTD
Type
Reset
RTD
Type
Reset
Bit/Field
Name
Type
31:0
RTD
R/W
Reset
Description
0x0000.0000 Hibernation Module NV Registers[63:0]
128
October 09, 2007
Preliminary
LM3S1911 Microcontroller
8
Internal Memory
The LM3S1911 microcontroller comes with 64 KB of bit-banded SRAM and 256 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.
8.1
Block Diagram
Figure 8-1. Flash Block Diagram
Flash Timing
USECRL
Flash Control
ICode
Cortex-M3
DCode
FMA
Flash Array
FMD
FMC
System Bus
FCRIS
FCIM
FCMISC
Bridge
APB
Flash Protection
User Registers
USER_DBG
SRAM Array
8.2
FMPREn
USER_REG0
FMPPEn
USER_REG1
Functional Description
This section describes the functionality of both the flash and SRAM memories.
8.2.1
SRAM Memory
®
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 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.
The bit-band alias is calculated by using the formula:
October 09, 2007
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Preliminary
Internal Memory
bit-band alias = bit-band base + (byte offset * 32) + (bit number * 4)
For example, if bit 3 at address 0x2000.1000 is to be modified, the bit-band alias is calculated as:
0x2200.0000 + (0x1000 * 32) + (3 * 4) = 0x2202.000C
With the alias address calculated, an instruction performing a read/write to address 0x2202.000C
allows direct access to only bit 3 of the byte at address 0x2000.1000.
For details about bit-banding, please refer to Chapter 4, “Memory Map” in the ARM® Cortex™-M3
Technical Reference Manual.
8.2.2
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. An individual 32-bit word can be
programmed to change bits that are currently 1 to a 0. These blocks are paired into a set of 2-KB
blocks that can be individually protected. The protection allows blocks to 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.
See also “Serial Flash Loader” on page 407 for a preprogrammed flash-resident utility used to
download code to the flash memory of a device without the use of a debug interface.
8.2.2.1
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.
On reset, the USECRL register is loaded with a value that configures the flash timing so that it works
with the maximum clock rate of the part. If software changes the system operating frequency, the
new operating frequency minus 1 (in MHz) 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 (20-1) must be written to the USECRL register.
8.2.2.2
Flash Memory Protection
The user is provided two forms of flash protection per 2-KB flash blocks in four pairs of 32-bit wide
registers. The protection policy for each form is controlled by individual bits (per policy per block)
in the FMPPEn and FMPREn registers.
■ Flash Memory Protection Program Enable (FMPPEn): If set, the block may be programmed
(written) or erased. If cleared, the block may not be changed.
■ Flash Memory Protection Read Enable (FMPREn): 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.
The policies may be combined as shown in Table 8-1 on page 131.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Table 8-1. Flash Protection Policy Combinations
FMPPEn FMPREn Protection
0
0
Execute-only protection. The block may only be executed and may not be written or erased. This mode
is used to protect code.
1
0
The block may be written, erased or executed, but not read. This combination is unlikely to be used.
0
1
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.
1
1
No protection. The block may be written, erased, executed or read.
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 FMPREn and FMPPEn 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. Details on
programming these bits are discussed in “Nonvolatile Register Programming” on page 132.
8.3
Flash Memory Initialization and Configuration
8.3.1
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.
8.3.1.1
To program a 32-bit word
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 0xA442.0001) to the FMC register.
4. Poll the FMC register until the WRITE bit is cleared.
8.3.1.2
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 0xA442.0002) to the FMC register.
3. Poll the FMC register until the ERASE bit is cleared.
8.3.1.3
To perform a mass erase of the flash
1. Write the flash write key and the MERASE bit (a value of 0xA442.0004) to the FMC register.
2. Poll the FMC register until the MERASE bit is cleared.
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Internal Memory
8.3.2
Nonvolatile Register Programming
This section discusses how to update registers that are resident within the flash memory itself.
These registers exist in a separate space from the main flash array and are not affected by an
ERASE or MASS ERASE operation. These nonvolatile registers are updated by using the COMT bit
in the FMC register to activate a write operation. For the USER_DBG register, the data to be written
must be loaded into the FMD register before it is "committed". All other registers are R/W and can
have their operation tried before committing them to nonvolatile memory.
Important: These registers can only have bits changed from 1 to 0 by the user and there is no
mechanism for the user to erase them back to a 1 value.
In addition, the USER_REG0, USER_REG1, and USER_DBG use bit 31 (NW) of their respective
registers to indicate that they are available for user write. These three registers can only be written
once whereas the flash protection registers may be written multiple times. Table 8-2 on page 132
provides the FMA address required for commitment of each of the registers and the source of the
data to be written when the COMT bit of the FMC register is written with a value of 0xA442.0008.
After writing the COMT bit, the user may poll the FMC register to wait for the commit operation to
complete.
a
Table 8-2. Flash Resident Registers
Register to be Committed FMA Value
Data Source
FMPRE0
0x0000.0000 FMPRE0
FMPRE1
0x0000.0002 FMPRE1
FMPRE2
0x0000.0004 FMPRE2
FMPRE3
0x0000.0008 FMPRE3
FMPPE0
0x0000.0001 FMPPE0
FMPPE1
0x0000.0003 FMPPE1
FMPPE2
0x0000.0005 FMPPE2
FMPPE3
0x0000.0007 FMPPE3
USER_REG0
0x8000.0000 USER_REG0
USER_REG1
0x8000.0001 USER_REG1
USER_DBG
0x7510.0000 FMD
®
a. Which FMPREn and FMPPEn registers are available depend on the flash size of your particular Stellaris device.
8.4
Register Map
Table 8-3 on page 132 lists the Flash memory and control registers. The offset listed is a hexadecimal
increment to the register's address. The FMA, FMD, FMC, FCRIS, FCIM, and FCMISC registers
are relative to the Flash control base address of 0x400F.D000. The FMPREn, FMPPEn, USECRL,
USER_DBG, and USER_REGn registers are relative to the System Control base address of
0x400F.E000.
Table 8-3. Flash Register Map
Offset
Name
Type
Reset
R/W
0x0000.0000
Description
See
page
Flash Control Offset
0x000
FMA
Flash Memory Address
132
134
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Description
See
page
Offset
Name
Type
Reset
0x004
FMD
R/W
0x0000.0000
Flash Memory Data
135
0x008
FMC
R/W
0x0000.0000
Flash Memory Control
136
0x00C
FCRIS
RO
0x0000.0000
Flash Controller Raw Interrupt Status
138
0x010
FCIM
R/W
0x0000.0000
Flash Controller Interrupt Mask
139
0x014
FCMISC
R/W1C
0x0000.0000
Flash Controller Masked Interrupt Status and Clear
140
System Control Offset
0x130
FMPRE0
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 0
142
0x200
FMPRE0
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 0
142
0x134
FMPPE0
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 0
143
0x400
FMPPE0
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 0
143
0x140
USECRL
R/W
0x31
USec Reload
141
0x1D0
USER_DBG
R/W
0xFFFF.FFFE
User Debug
144
0x1E0
USER_REG0
R/W
0xFFFF.FFFF
User Register 0
145
0x1E4
USER_REG1
R/W
0xFFFF.FFFF
User Register 1
146
0x204
FMPRE1
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 1
147
0x208
FMPRE2
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 2
148
0x20C
FMPRE3
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 3
149
0x404
FMPPE1
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 1
150
0x408
FMPPE2
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 2
151
0x40C
FMPPE3
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 3
152
8.5
Flash Register Descriptions (Flash Control Offset)
The remainder of this section lists and describes the Flash Memory registers, in numerical order by
address offset. Registers in this section are relative to the Flash control base address of 0x400F.D000.
October 09, 2007
133
Preliminary
Internal Memory
Register 1: 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 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)
Base 0x400F.D000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
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
R/W
0
R/W
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
R/W
0
reserved
Type
Reset
16
OFFSET
OFFSET
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:18
reserved
RO
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
17:0
OFFSET
R/W
0x0
Address Offset
Address offset in flash where operation is performed, except for
nonvolatile registers (see “Nonvolatile Register Programming” on page
132 for details on values for this field).
134
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 2: 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)
Base 0x400F.D000
Offset 0x004
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
R/W
0
DATA
Type
Reset
DATA
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:0
DATA
R/W
0x0
Data Value
Data value for write operation.
October 09, 2007
135
Preliminary
Internal Memory
Register 3: 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 134). If the access is a write
access, the data contained in the Flash Memory Data (FMD) register (see page 135) 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)
Base 0x400F.D000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
WRKEY
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
31:16
WRKEY
WO
0x0
COMT
R/W
0
MERASE ERASE
R/W
0
R/W
0
WRITE
R/W
0
Description
Flash Write Key
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.
15:4
reserved
RO
0x0
3
COMT
R/W
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Commit Register Value
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 μs.
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.
136
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
1
ERASE
R/W
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 µs.
October 09, 2007
137
Preliminary
Internal Memory
Register 4: 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)
Base 0x400F.D000
Offset 0x00C
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
PRIS
ARIS
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
PRIS
RO
0
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 136).
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 (FMPREn) and Flash Memory Protection
Program Enable (FMPPEn) registers. Otherwise, no access has tried
to improperly access the flash.
138
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 5: Flash Controller Interrupt Mask (FCIM), offset 0x010
This register controls whether the flash controller generates interrupts to the controller.
Flash Controller Interrupt Mask (FCIM)
Base 0x400F.D000
Offset 0x010
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
PMASK
AMASK
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
PMASK
R/W
0
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.
October 09, 2007
139
Preliminary
Internal Memory
Register 6: 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 signalling the interrupt. Second, it serves as the method to clear the
interrupt reporting.
Flash Controller Masked Interrupt Status and Clear (FCMISC)
Base 0x400F.D000
Offset 0x014
Type R/W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
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
1
0
PMISC
AMISC
R/W1C
0
R/W1C
0
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
PMISC
R/W1C
0
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 138) 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.
8.6
Flash Register Descriptions (System Control Offset)
The remainder of this section lists and describes the Flash Memory registers, in numerical order by
address offset. Registers in this section are relative to the System Control base address of
0x400F.E000.
140
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 7: USec Reload (USECRL), offset 0x140
Note:
Offset is relative to System Control base address of 0x400F.E000
This register is provided as a means of creating a 1-μs 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)
Base 0x400F.E000
Offset 0x140
Type R/W, reset 0x31
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
USEC
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
1
R/W
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
USEC
R/W
0x31
Microsecond Reload Value
MHz -1 of the controller clock when the flash is being erased or
programmed.
USEC should be set to 0x31 (50 MHz) whenever the flash is being erased
or programmed.
October 09, 2007
141
Preliminary
Internal Memory
Register 8: Flash Memory Protection Read Enable 0 (FMPRE0), offset 0x130
and 0x200
Note:
This register is aliased for backwards compatability.
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Read Enable 0 (FMPRE0)
Base 0x400F.D000
Offset 0x130 and 0x200
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
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
8
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
1
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Read Enable
Enables 2-KB flash blocks to be executed or read. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
142
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 9: Flash Memory Protection Program Enable 0 (FMPPE0), offset
0x134 and 0x400
Note:
This register is aliased for backwards compatability.
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Program Enable 0 (FMPPE0)
Base 0x400F.D000
Offset 0x134 and 0x400
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PROG_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
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
8
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
PROG_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
R/W
1
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
October 09, 2007
143
Preliminary
Internal Memory
Register 10: User Debug (USER_DBG), offset 0x1D0
Note:
Offset is relative to System Control base address of 0x400FE000.
This register provides a write-once mechanism to disable external debugger access to the device
in addition to 27 additional bits of user-defined data. The DBG0 bit (bit 0) is set to 0 from the factory
and the DBG1 bit (bit 1) is set to 1, which enables external debuggers. Changing the DBG1 bit to 0
disables any external debugger access to the device permanently, starting with the next power-up
cycle of the device. The NOTWRITTEN bit (bit 31) indicates that the register is available to be written
and is controlled through hardware to ensure that the register is only written once.
User Debug (USER_DBG)
Base 0x400F.E000
Offset 0x1D0
Type R/W, reset 0xFFFF.FFFE
31
30
29
28
27
26
25
24
NW
Type
Reset
23
22
21
20
19
18
17
16
R/W
1
R/W
1
DATA
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
8
7
6
5
4
3
2
DATA
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
Reset
31
NW
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
DBG1
DBG0
R/W
1
R/W
0
Description
User Debug Not Written
Specifies that this 32-bit dword has not been written.
30:2
DATA
R/W
0x1FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be written once.
1
DBG1
R/W
1
Debug Control 1
The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available.
0
DBG0
R/W
0
Debug Control 0
The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available.
144
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 11: User Register 0 (USER_REG0), offset 0x1E0
Note:
Offset is relative to System Control base address of 0x400FE000.
This register provides 31 bits of user-defined data that is non-volatile and can only be written once.
Bit 31 indicates that the register is available to be written and is controlled through hardware to
ensure that the register is only written once. The write-once characteristics of this register are useful
for keeping static information like communication addresses that need to be unique per part and
would otherwise require an external EEPROM or other non-volatile device.
User Register 0 (USER_REG0)
Base 0x400F.E000
Offset 0x1E0
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
NW
Type
Reset
23
22
21
20
19
18
17
16
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
7
6
5
4
3
2
1
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
DATA
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
8
DATA
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
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
Specifies that this 32-bit dword has not been written.
30:0
DATA
R/W
0x7FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be written once.
October 09, 2007
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Internal Memory
Register 12: User Register 1 (USER_REG1), offset 0x1E4
Note:
Offset is relative to System Control base address of 0x400FE000.
This register provides 31 bits of user-defined data that is non-volatile and can only be written once.
Bit 31 indicates that the register is available to be written and is controlled through hardware to
ensure that the register is only written once. The write-once characteristics of this register are useful
for keeping static information like communication addresses that need to be unique per part and
would otherwise require an external EEPROM or other non-volatile device.
User Register 1 (USER_REG1)
Base 0x400F.E000
Offset 0x1E4
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
NW
Type
Reset
23
22
21
20
19
18
17
16
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
7
6
5
4
3
2
1
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
DATA
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
8
DATA
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
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
Specifies that this 32-bit dword has not been written.
30:0
DATA
R/W
0x7FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be written once.
146
October 09, 2007
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LM3S1911 Microcontroller
Register 13: Flash Memory Protection Read Enable 1 (FMPRE1), offset 0x204
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Read Enable 1 (FMPRE1)
Base 0x400F.E000
Offset 0x204
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
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
8
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
1
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Read Enable
Enables 2-KB flash blocks to be executed or read. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
October 09, 2007
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Internal Memory
Register 14: Flash Memory Protection Read Enable 2 (FMPRE2), offset 0x208
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Read Enable 2 (FMPRE2)
Base 0x400F.E000
Offset 0x208
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
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
8
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
1
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Read Enable
Enables 2-KB flash blocks to be executed or read. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
148
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 15: Flash Memory Protection Read Enable 3 (FMPRE3), offset 0x20C
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Read Enable 3 (FMPRE3)
Base 0x400F.E000
Offset 0x20C
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
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
8
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
READ_ENABLE
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
1
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Read Enable
Enables 2-KB flash blocks to be executed or read. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
October 09, 2007
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Preliminary
Internal Memory
Register 16: Flash Memory Protection Program Enable 1 (FMPPE1), offset
0x404
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Program Enable 1 (FMPPE1)
Base 0x400F.E000
Offset 0x404
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
8
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
23
22
21
20
19
18
17
16
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
PROG_ENABLE
Type
Reset
PROG_ENABLE
Type
Reset
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
150
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 17: Flash Memory Protection Program Enable 2 (FMPPE2), offset
0x408
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Program Enable 2 (FMPPE2)
Base 0x400F.E000
Offset 0x408
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
8
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
23
22
21
20
19
18
17
16
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
PROG_ENABLE
Type
Reset
PROG_ENABLE
Type
Reset
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
October 09, 2007
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Preliminary
Internal Memory
Register 18: Flash Memory Protection Program Enable 3 (FMPPE3), offset
0x40C
Note:
Offset is relative to System Control base address of 0x400FE000.
This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the
execute-only bits). This register is loaded during the power-on reset sequence. The factory settings
for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves
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 the "Flash Memory Protection" section.
Flash Memory Protection Program Enable 3 (FMPPE3)
Base 0x400F.E000
Offset 0x40C
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
8
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
23
22
21
20
19
18
17
16
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
PROG_ENABLE
Type
Reset
PROG_ENABLE
Type
Reset
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in the table “Flash Protection Policy Combinations”.
Value
Description
0xFFFFFFFF Enables 256 KB of flash.
152
October 09, 2007
Preliminary
LM3S1911 Microcontroller
9
General-Purpose Input/Outputs (GPIOs)
The GPIO module is composed of eight physical GPIO blocks, each corresponding to an individual
GPIO port (Port A, Port B, Port C, Port D, Port E, Port F, Port G, and Port H). The GPIO module is
FiRM-compliant and supports 23-60 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
9.1
Functional Description
Important: All GPIO pins are tri-stated by default (GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0,
and GPIOPUR=0), with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]).
The JTAG/SWD pins default to their JTAG/SWD functionality (GPIOAFSEL=1,
GPIODEN=1 and GPIOPUR=1). A Power-On-Reset (POR) or asserting RST puts both
groups of pins back to their default state.
Each GPIO port is a separate hardware instantiation of the same physical block. The LM3S1911
microcontroller contains eight ports and thus eight of these physical GPIO blocks.
9.1.1
Data Control
The data control registers allow software to configure the operational modes of the GPIOs. The data
direction register configures the GPIO as an input or an output while the data register either captures
incoming data or drives it out to the pads.
9.1.1.1
Data Direction Operation
The GPIO Direction (GPIODIR) register (see page 160) is used to configure each individual pin as
an input or output. When the data direction bit is set to 0, the GPIO is configured as an input and
the corresponding data register bit will capture and store the value on the GPIO port. When the data
October 09, 2007
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Preliminary
General-Purpose Input/Outputs (GPIOs)
direction bit is set to 1, the GPIO is configured as an output and the corresponding data register bit
will be driven out on the GPIO port.
9.1.1.2
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 159) 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 9-1 on page 154, where u is data unchanged by the write.
Figure 9-1. GPIODATA Write Example
ADDR[9:2]
0x098
9
8
7
6
5
4
3
2
1
0
0
0
1
0
0
1
1
0
1
0
0xEB
1
1
1
0
1
0
1
1
GPIODATA
u
u
1
u
u
0
1
u
7
6
5
4
3
2
1
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 9-2 on page 154.
Figure 9-2. GPIODATA Read Example
9.1.2
ADDR[9:2]
0x0C4
9
8
7
6
5
4
3
2
1
0
0
0
1
1
0
0
0
1
0
0
GPIODATA
1
0
1
1
1
1
1
0
Returned Value
0
0
1
1
0
0
0
0
7
6
5
4
3
2
1
0
Interrupt Control
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:
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October 09, 2007
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LM3S1911 Microcontroller
■ GPIO Interrupt Sense (GPIOIS) register (see page 161)
■ GPIO Interrupt Both Edges (GPIOIBE) register (see page 162)
■ GPIO Interrupt Event (GPIOIEV) register (see page 163)
Interrupts are enabled/disabled via the GPIO Interrupt Mask (GPIOIM) register (see page 164).
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 page 165 and page 166). 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.
Interrupts are cleared by writing a 1 to the GPIO Interrupt Clear (GPIOICR) register (see page 167).
When programming the following interrupt control registers, 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.
9.1.3
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 168), 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.
9.1.4
Commit Control
The commit control registers provide a layer of protection against accidental programming of critical
hardware peripherals. Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL)
register (see page 168) are not committed to storage unless the GPIO Lock (GPIOLOCK) register
(see page 178) has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register
(see page 179) have been set to 1.
9.1.5
Pad Control
The pad control registers allow for GPIO pad configuration by software based on the application
requirements. The pad control registers include the GPIODR2R, GPIODR4R, GPIODR8R, GPIOODR,
GPIOPUR, GPIOPDR, GPIOSLR, and GPIODEN registers.
9.1.6
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.
9.2
Initialization and Configuration
To use the GPIO, the peripheral clock must be enabled by setting the appropriate GPIO Port bit
field (GPIOn) in the RCGC2 register.
On reset, all GPIO pins (except for the five JTAG pins) are configured out of reset to be undriven
(tristate): GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, and GPIOPUR=0. Table 9-1 on page 156
shows all possible configurations of the GPIO pads and the control register settings required to
achieve them. Table 9-2 on page 156 shows how a rising edge interrupt would be configured for pin
2 of a GPIO port.
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Preliminary
General-Purpose Input/Outputs (GPIOs)
Table 9-1. GPIO Pad Configuration Examples
a
Configuration
GPIO Register Bit Value
AFSEL
DIR
ODR
DEN
PUR
PDR
?
?
DR2R
DR4R
DR8R
X
X
X
SLR
Digital Input (GPIO)
0
0
0
1
X
Digital Output (GPIO)
0
1
0
1
?
?
?
?
?
?
Open Drain Input
(GPIO)
0
0
1
1
X
X
X
X
X
X
Open Drain Output
(GPIO)
0
1
1
1
X
X
?
?
?
?
Open Drain
Input/Output (I2C)
1
X
1
1
X
X
?
?
?
?
Digital Input (Timer
CCP)
1
X
0
1
?
?
X
X
X
X
Digital Output (Timer
PWM)
1
X
0
1
?
?
?
?
?
?
Digital Input/Output
(SSI)
1
X
0
1
?
?
?
?
?
?
Digital Input/Output
(UART)
1
X
0
1
?
?
?
?
?
?
Analog Input
(Comparator)
0
0
0
0
0
0
X
X
X
X
Digital Output
(Comparator)
1
X
0
1
?
?
?
?
?
?
a. X=Ignored (don’t care bit)
?=Can be either 0 or 1, depending on the configuration
Table 9-2. GPIO Interrupt Configuration Example
Register
Desired
Interrupt
Event
Trigger
GPIOIS
0=edge
GPIOIBE
0=single
edge
a
Pin 2 Bit Value
7
6
5
4
3
2
1
0
X
X
X
X
X
0
X
X
X
X
X
X
X
0
X
X
X
X
X
X
X
1
X
X
0
0
0
0
0
1
0
0
1=level
1=both
edges
GPIOIEV
0=Low level,
or negative
edge
1=High level,
or positive
edge
GPIOIM
0=masked
1=not
masked
a. X=Ignored (don’t care bit)
156
October 09, 2007
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LM3S1911 Microcontroller
9.3
Register Map
Table 9-3 on page 157 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: 0x4000.4000
■ GPIO Port B: 0x4000.5000
■ GPIO Port C: 0x4000.6000
■ GPIO Port D: 0x4000.7000
■ GPIO Port E: 0x4002.4000
■ GPIO Port F: 0x4002.5000
■ GPIO Port G: 0x4002.6000
■ GPIO Port H: 0x4002.7000
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. In those
cases, writing to those unconnected bits has no effect and reading those unconnected
bits returns no meaningful data.
Note:
The default reset value for the GPIOAFSEL, GPIOPUR, and GPIODEN registers are
0x0000.0000 for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and
PC[3:0]). These five pins default to JTAG/SWD functionality. Because of this, the default
reset value of these registers for GPIO Port B is 0x0000.0080 while the default reset value
for Port C is 0x0000.000F.
The default register type for the GPIOCR register is RO for all GPIO pins, with the exception
of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins are currently the only
GPIOs that are protected by the GPIOCR register. Because of this, the register type for
GPIO Port B7 and GPIO Port C[3:0] is R/W.
The default reset value for the GPIOCR register is 0x0000.00FF for all GPIO pins, with the
exception of the five JTAG/SWD pins (PB7 and PC[3:0]). To ensure that the JTAG port
is not accidentally programmed as a GPIO, these five pins default to non-commitable.
Because of this, the default reset value of GPIOCR for GPIO Port B is 0x0000.007F while
the default reset value of GPIOCR for Port C is 0x0000.00F0.
Table 9-3. GPIO Register Map
Description
See
page
Offset
Name
Type
Reset
0x000
GPIODATA
R/W
0x0000.0000
GPIO Data
159
0x400
GPIODIR
R/W
0x0000.0000
GPIO Direction
160
0x404
GPIOIS
R/W
0x0000.0000
GPIO Interrupt Sense
161
0x408
GPIOIBE
R/W
0x0000.0000
GPIO Interrupt Both Edges
162
0x40C
GPIOIEV
R/W
0x0000.0000
GPIO Interrupt Event
163
October 09, 2007
157
Preliminary
General-Purpose Input/Outputs (GPIOs)
Name
Type
Reset
0x410
GPIOIM
R/W
0x0000.0000
GPIO Interrupt Mask
164
0x414
GPIORIS
RO
0x0000.0000
GPIO Raw Interrupt Status
165
0x418
GPIOMIS
RO
0x0000.0000
GPIO Masked Interrupt Status
166
0x41C
GPIOICR
W1C
0x0000.0000
GPIO Interrupt Clear
167
0x420
GPIOAFSEL
R/W
-
GPIO Alternate Function Select
168
0x500
GPIODR2R
R/W
0x0000.00FF
GPIO 2-mA Drive Select
170
0x504
GPIODR4R
R/W
0x0000.0000
GPIO 4-mA Drive Select
171
0x508
GPIODR8R
R/W
0x0000.0000
GPIO 8-mA Drive Select
172
0x50C
GPIOODR
R/W
0x0000.0000
GPIO Open Drain Select
173
0x510
GPIOPUR
R/W
-
GPIO Pull-Up Select
174
0x514
GPIOPDR
R/W
0x0000.0000
GPIO Pull-Down Select
175
0x518
GPIOSLR
R/W
0x0000.0000
GPIO Slew Rate Control Select
176
0x51C
GPIODEN
R/W
-
GPIO Digital Enable
177
0x520
GPIOLOCK
R/W
0x0000.0001
GPIO Lock
178
0x524
GPIOCR
-
-
GPIO Commit
179
0xFD0
GPIOPeriphID4
RO
0x0000.0000
GPIO Peripheral Identification 4
181
0xFD4
GPIOPeriphID5
RO
0x0000.0000
GPIO Peripheral Identification 5
182
0xFD8
GPIOPeriphID6
RO
0x0000.0000
GPIO Peripheral Identification 6
183
0xFDC
GPIOPeriphID7
RO
0x0000.0000
GPIO Peripheral Identification 7
184
0xFE0
GPIOPeriphID0
RO
0x0000.0061
GPIO Peripheral Identification 0
185
0xFE4
GPIOPeriphID1
RO
0x0000.0000
GPIO Peripheral Identification 1
186
0xFE8
GPIOPeriphID2
RO
0x0000.0018
GPIO Peripheral Identification 2
187
0xFEC
GPIOPeriphID3
RO
0x0000.0001
GPIO Peripheral Identification 3
188
0xFF0
GPIOPCellID0
RO
0x0000.000D
GPIO PrimeCell Identification 0
189
0xFF4
GPIOPCellID1
RO
0x0000.00F0
GPIO PrimeCell Identification 1
190
0xFF8
GPIOPCellID2
RO
0x0000.0005
GPIO PrimeCell Identification 2
191
0xFFC
GPIOPCellID3
RO
0x0000.00B1
GPIO PrimeCell Identification 3
192
9.4
Description
See
page
Offset
Register Descriptions
The remainder of this section lists and describes the GPIO registers, in numerical order by address
offset.
158
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 160).
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
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
reserved
Type
Reset
reserved
Type
Reset
DATA
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DATA
R/W
0x00
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 154 for examples of
reads and writes.
October 09, 2007
159
Preliminary
General-Purpose Input/Outputs (GPIOs)
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x400
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
DIR
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DIR
R/W
0x00
GPIO Data Direction
The DIR values are defined as follows:
Value Description
0
Pins are inputs.
1
Pins are outputs.
160
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x404
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
IS
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
IS
R/W
0x00
GPIO Interrupt Sense
The IS values are defined as follows:
Value Description
0
Edge on corresponding pin is detected (edge-sensitive).
1
Level on corresponding pin is detected (level-sensitive).
October 09, 2007
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Preliminary
General-Purpose Input/Outputs (GPIOs)
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 161) 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 163). Clearing a bit
configures the pin to be controlled by GPIOIEV. All bits are cleared by a reset.
GPIO Interrupt Both Edges (GPIOIBE)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x408
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
IBE
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
IBE
R/W
0x00
GPIO Interrupt Both Edges
The IBE values are defined as follows:
Value Description
0
Interrupt generation is controlled by the GPIO Interrupt Event
(GPIOIEV) register (see page 163).
1
Both edges on the corresponding pin trigger an interrupt.
Note:
162
Single edge is determined by the corresponding bit
in GPIOIEV.
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 161). 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x40C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
IEV
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
IEV
R/W
0x00
GPIO Interrupt Event
The IEV values are defined as follows:
Value Description
0
Falling edge or Low levels on corresponding pins trigger
interrupts.
1
Rising edge or High levels on corresponding pins trigger
interrupts.
October 09, 2007
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Preliminary
General-Purpose Input/Outputs (GPIOs)
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x410
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
IME
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
IME
R/W
0x00
GPIO Interrupt Mask Enable
The IME values are defined as follows:
Value Description
0
Corresponding pin interrupt is masked.
1
Corresponding pin interrupt is not masked.
164
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 164). 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x414
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RIS
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
RIS
RO
0x00
GPIO Interrupt Raw Status
Reflects the status of interrupt trigger condition detection on pins (raw,
prior to masking).
The RIS values are defined as follows:
Value Description
0
Corresponding pin interrupt requirements not met.
1
Corresponding pin interrupt has met requirements.
October 09, 2007
165
Preliminary
General-Purpose Input/Outputs (GPIOs)
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.
GPIOMIS is the state of the interrupt after masking.
GPIO Masked Interrupt Status (GPIOMIS)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x418
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
MIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
MIS
RO
0x00
GPIO Masked Interrupt Status
Masked value of interrupt due to corresponding pin.
The MIS values are defined as follows:
Value Description
0
Corresponding GPIO line interrupt not active.
1
Corresponding GPIO line asserting interrupt.
166
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x41C
Type W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
W1C
0
W1C
0
W1C
0
W1C
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
IC
RO
0
RO
0
RO
0
RO
0
W1C
0
W1C
0
W1C
0
W1C
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
IC
W1C
0x00
GPIO Interrupt Clear
The IC values are defined as follows:
Value Description
0
Corresponding interrupt is unaffected.
1
Corresponding interrupt is cleared.
October 09, 2007
167
Preliminary
General-Purpose Input/Outputs (GPIOs)
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.
The commit control registers provide a layer of protection against accidental programming of critical
hardware peripherals. Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL)
register (see page 168) are not committed to storage unless the GPIO Lock (GPIOLOCK) register
(see page 178) has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register
(see page 179) have been set to 1.
Important: All GPIO pins are tri-stated by default (GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0,
and GPIOPUR=0), with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]).
The JTAG/SWD pins default to their JTAG/SWD functionality (GPIOAFSEL=1,
GPIODEN=1 and GPIOPUR=1). A Power-On-Reset (POR) or asserting RST puts both
groups of pins back to their default state.
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 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x420
Type R/W, reset 31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
reserved
Type
Reset
reserved
Type
Reset
AFSEL
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
168
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
7:0
AFSEL
R/W
-
Description
GPIO Alternate Function Select
The AFSEL values are defined as follows:
Value Description
0
Software control of corresponding GPIO line (GPIO mode).
1
Hardware control of corresponding GPIO line (alternate
hardware function).
Note:
October 09, 2007
The default reset value for the GPIOAFSEL,
GPIOPUR, and GPIODEN registers are 0x0000.0000
for all GPIO pins, with the exception of the five
JTAG/SWD pins (PB7 and PC[3:0]). These five pins
default to JTAG/SWD functionality. Because of this,
the default reset value of these registers for GPIO
Port B is 0x0000.0080 while the default reset value
for Port C is 0x0000.000F.
169
Preliminary
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x500
Type R/W, reset 0x0000.00FF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
DRV2
RO
0
RO
0
RO
0
RO
0
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DRV2
R/W
0xFF
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.
170
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x504
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
DRV4
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DRV4
R/W
0x00
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.
October 09, 2007
171
Preliminary
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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x508
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
DRV8
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DRV8
R/W
0x00
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.
172
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 177). 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.
When using the I2C module, the GPIO Alternate Function Select (GPIOAFSEL) register bit for
PB2 and PB3 should be set to 1 (see examples in “Initialization and Configuration” on page 155).
GPIO Open Drain Select (GPIOODR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x50C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
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
reserved
Type
Reset
reserved
Type
Reset
ODE
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
ODE
R/W
0x00
Output Pad Open Drain Enable
The ODE values are defined as follows:
Value Description
0
Open drain configuration is disabled.
1
Open drain configuration is enabled.
October 09, 2007
173
Preliminary
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 175).
GPIO Pull-Up Select (GPIOPUR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x510
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PUE
RO
0
RO
0
RO
0
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PUE
R/W
-
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.
Note:
174
The default reset value for the GPIOAFSEL, GPIOPUR, and
GPIODEN registers are 0x0000.0000 for all GPIO pins, with
the exception of the five JTAG/SWD pins (PB7 and PC[3:0]).
These five pins default to JTAG/SWD functionality. Because
of this, the default reset value of these registers for GPIO Port
B is 0x0000.0080 while the default reset value for Port C is
0x0000.000F.
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 174).
GPIO Pull-Down Select (GPIOPDR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x514
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PDE
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PDE
R/W
0x00
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.
October 09, 2007
175
Preliminary
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 172).
GPIO Slew Rate Control Select (GPIOSLR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x518
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
SRL
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
SRL
R/W
0x00
Slew Rate Limit Enable (8-mA drive only)
The SRL values are defined as follows:
Value Description
0
Slew rate control disabled.
1
Slew rate control enabled.
176
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 18: GPIO Digital Enable (GPIODEN), offset 0x51C
The GPIODEN register is the digital enable register. By default, with the exception of the GPIO
signals used for JTAG/SWD function, all other GPIO signals are configured out of reset to be undriven
(tristate). Their digital function is disabled; they do not drive a logic value on the pin and they do not
allow the pin voltage into the GPIO receiver. To use the pin in a digital function (either GPIO or
alternate function), the corresponding GPIODEN bit must be set.
GPIO Digital Enable (GPIODEN)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x51C
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
DEN
RO
0
RO
0
RO
0
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DEN
R/W
-
Digital Enable
The DEN values are defined as follows:
Value Description
0
Digital functions disabled.
1
Digital functions enabled.
Note:
October 09, 2007
The default reset value for the GPIOAFSEL,
GPIOPUR, and GPIODEN registers are 0x0000.0000
for all GPIO pins, with the exception of the five
JTAG/SWD pins (PB7 and PC[3:0]). These five pins
default to JTAG/SWD functionality. Because of this,
the default reset value of these registers for GPIO
Port B is 0x0000.0080 while the default reset value
for Port C is 0x0000.000F.
177
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 19: GPIO Lock (GPIOLOCK), offset 0x520
The GPIOLOCK register enables write access to the GPIOCR register (see page 179). Writing
0x1ACCE551 to the GPIOLOCK register will unlock the GPIOCR register. Writing any other value
to the GPIOLOCK register re-enables the locked state. Reading the GPIOLOCK register returns
the lock status rather than the 32-bit value that was previously written. Therefore, when write accesses
are disabled, or locked, reading the GPIOLOCK register returns 0x00000001. When write accesses
are enabled, or unlocked, reading the GPIOLOCK register returns 0x00000000.
GPIO Lock (GPIOLOCK)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x520
Type R/W, reset 0x0000.0001
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
7
6
5
4
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
1
LOCK
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
15
14
13
12
11
10
9
8
LOCK
Type
Reset
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
31:0
LOCK
R/W
R/W
0
R/W
0
Reset
R/W
0
Description
0x0000.0001 GPIO Lock
A write of the value 0x1ACCE551 unlocks the GPIO Commit (GPIOCR)
register 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:
Value
Description
0x0000.0001 locked
0x0000.0000 unlocked
178
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 20: GPIO Commit (GPIOCR), offset 0x524
The GPIOCR register is the commit register. The value of the GPIOCR register determines which
bits of the GPIOAFSEL register will be committed when a write to the GPIOAFSEL register is
performed. If a bit in the GPIOCR register is a zero, the data being written to the corresponding bit
in the GPIOAFSEL register will not be committed and will retain its previous value. If a bit in the
GPIOCR register is a one, the data being written to the corresponding bit of the GPIOAFSEL register
will be committed to the register and will reflect the new value.
The contents of the GPIOCR register can only be modified if the GPIOLOCK register is unlocked.
Writes to the GPIOCR register will be ignored if the GPIOLOCK register is locked.
Important: This register is designed to prevent accidental programming of the GPIOAFSEL registers
that control connectivity to the JTAG/SWD debug hardware. By initializing the bits of
the GPIOCR register to 0 for PB7 and PC[3:0], the JTAG/SWD debug port can only
be converted to GPIOs through a deliberate set of writes to the GPIOLOCK, GPIOCR,
and GPIOAFSEL registers.
Because this protection is currently only implemented on the JTAG/SWD pins on PB7
and PC[3:0], all of the other bits in the GPIOCR registers cannot be written with 0x0.
These bits are hardwired to 0x1, ensuring that it is always possible to commit new
values to the GPIOAFSEL register bits of these other pins.
GPIO Commit (GPIOCR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0x524
Type -, reset 31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
-
-
-
-
-
-
-
-
reserved
Type
Reset
reserved
Type
Reset
CR
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
179
Preliminary
General-Purpose Input/Outputs (GPIOs)
Bit/Field
Name
Type
Reset
7:0
CR
-
-
Description
GPIO Commit
On a bit-wise basis, any bit set allows the corresponding GPIOAFSEL
bit to be set to its alternate function.
Note:
The default register type for the GPIOCR register is RO for
all GPIO pins, with the exception of the five JTAG/SWD pins
(PB7 and PC[3:0]). These five pins are currently the only
GPIOs that are protected by the GPIOCR register. Because
of this, the register type for GPIO Port B7 and GPIO Port
C[3:0] is R/W.
The default reset value for the GPIOCR register is
0x0000.00FF for all GPIO pins, with the exception of the five
JTAG/SWD pins (PB7 and PC[3:0]). To ensure that the
JTAG port is not accidentally programmed as a GPIO, these
five pins default to non-commitable. Because of this, the
default reset value of GPIOCR for GPIO Port B is
0x0000.007F while the default reset value of GPIOCR for Port
C is 0x0000.00F0.
180
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 21: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFD0
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID4
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID4
RO
0x00
GPIO Peripheral ID Register[7:0]
October 09, 2007
181
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 22: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFD4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID5
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID5
RO
0x00
GPIO Peripheral ID Register[15:8]
182
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 23: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFD8
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID6
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID6
RO
0x00
GPIO Peripheral ID Register[23:16]
October 09, 2007
183
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 24: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFDC
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID7
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID7
RO
0x00
GPIO Peripheral ID Register[31:24]
184
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 25: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFE0
Type RO, reset 0x0000.0061
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID0
RO
0x61
GPIO Peripheral ID Register[7:0]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
185
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 26: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFE4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID1
RO
0x00
GPIO Peripheral ID Register[15:8]
Can be used by software to identify the presence of this peripheral.
186
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 27: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFE8
Type RO, reset 0x0000.0018
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
1
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID2
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID2
RO
0x18
GPIO Peripheral ID Register[23:16]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
187
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 28: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFEC
Type RO, reset 0x0000.0001
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID3
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID3
RO
0x01
GPIO Peripheral ID Register[31:24]
Can be used by software to identify the presence of this peripheral.
188
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 29: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFF0
Type RO, reset 0x0000.000D
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
1
RO
1
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID0
RO
0x0D
GPIO PrimeCell ID Register[7:0]
Provides software a standard cross-peripheral identification system.
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Register 30: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFF4
Type RO, reset 0x0000.00F0
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID1
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
1
RO
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID1
RO
0xF0
GPIO PrimeCell ID Register[15:8]
Provides software a standard cross-peripheral identification system.
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Register 31: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFF8
Type RO, reset 0x0000.0005
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
1
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID2
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID2
RO
0x05
GPIO PrimeCell ID Register[23:16]
Provides software a standard cross-peripheral identification system.
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Register 32: 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)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
Offset 0xFFC
Type RO, reset 0x0000.00B1
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID3
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
1
RO
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID3
RO
0xB1
GPIO PrimeCell ID Register[31:24]
Provides software a standard cross-peripheral identification system.
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10
General-Purpose Timers
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 four GPTM blocks (Timer0, Timer1,
Timer 2, and Timer 3). 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).
Note:
Timer2 is an internal timer and can only be used to generate internal interrupts.
®
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).
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 (for one-shot and periodic modes only)
– 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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10.1
Block Diagram
Figure 10-1. GPTM Module Block Diagram
0x0000 (Down Counter Modes)
TimerA Control
GPTMTAPMR
TA Comparator
GPTMTAPR
Clock / Edge
Detect
GPTMTAMATCHR
Interrupt / Config
TimerA
Interrupt
GPTMCFG
GPTMTAILR
GPTMAR
En
GPTMCTL
GPTMIMR
TimerB
Interrupt
CCP (even)
GPTMTAMR
RTC Divider
GPTMRIS
GPTMMIS
TimerB Control
GPTMICR
GPTMTBPMR
GPTMTBR En
Clock / Edge
Detect
GPTMTBPR
GPTMTBMATCHR
GPTMTBILR
CCP (odd)
TB Comparator
GPTMTBMR
0x0000 (Down Counter Modes)
System
Clock
10.2
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 205),
the GPTM TimerA Mode (GPTMTAMR) register (see page 206), and the GPTM TimerB Mode
(GPTMTBMR) register (see page 208). 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.
10.2.1
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 219) and the GPTM TimerB Interval Load (GPTMTBILR) register
(see page 220). The prescale counters are initialized to 0x00: the GPTM TimerA Prescale
(GPTMTAPR) register (see page 223) and the GPTM TimerB Prescale (GPTMTBPR) register (see
page 224).
10.2.2
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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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 219
■ GPTM TimerB Interval Load (GPTMTBILR) register [15:0], see page 220
■ GPTM TimerA (GPTMTAR) register [15:0], see page 227
■ GPTM TimerB (GPTMTBR) register [15:0], see page 228
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]
10.2.2.1 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 206), 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 210), the
timer begins counting down from its preloaded value. Once the 0x0000.0000 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 215), and holds it until it is cleared by writing the GPTM Interrupt
Clear (GPTMICR) register (see page 217). If the time-out interrupt is enabled in the GPTM Interrupt
Mask (GPTIMR) register (see page 213), the GPTM also sets the TATOMIS bit in the GPTM Masked
Interrupt Status (GPTMMIS) register (see page 216).
The output trigger is a one-clock-cycle pulse that is asserted when the counter hits the 0x0000.0000
state, and deasserted on the following clock cycle. It is enabled by setting the TAOTE bit in GPTMCTL.
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.
10.2.2.2 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
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General-Purpose Timers
loaded with a value of 0x0000.0001. All subsequent load values must be written to the GPTM TimerA
Match (GPTMTAMATCHR) register (see page 221) 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.
When software writes the TAEN bit inthe GPTMCTL register, the counter starts counting up from its
preloaded value of 0x0000.0001. When the current count value matches the preloaded value in the
GPTMTAMATCHR register, it rolls over to a value of 0x0000.0000 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.
10.2.3
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 205). This section describes each of the GPTM 16-bit modes of
operation. TimerA and TimerB have identical modes, so a single description is given using an n to
reference both.
10.2.3.1 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.
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 50-MHz clock with Tc=20 ns (clock period).
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Table 10-1. 16-Bit Timer With Prescaler Configurations
a
Prescale #Clock (T c) Max Time Units
00000000
1
1.3107
mS
00000001
2
2.6214
mS
00000010
3
3.9321
mS
------------
--
--
--
11111100
254
332.9229
mS
11111110
255
334.2336
mS
11111111
256
335.5443
mS
a. Tc is the clock period.
10.2.3.2 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 10-2 on page 198 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 10-2. 16-Bit Input Edge Count Mode Example
Timer reload
on next cycle
Count
Ignored
Ignored
0x000A
0x0009
0x0008
0x0007
0x0006
Timer stops,
flags
asserted
Input Signal
10.2.3.3 16-Bit Input Edge Time Mode
Note:
The prescaler is not available in 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 GPTMCnTL register.
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 10-3 on page 199 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 10-3. 16-Bit Input Edge Time Mode Example
Count
0xFFFF
GPTMTnR=X
GPTMTnR=Y
GPTMTnR=Z
Z
X
Y
Time
Input Signal
10.2.3.4 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.
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 10-4 on page 200 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 10-4. 16-Bit PWM Mode Example
Count
GPTMTnR=GPTMnMR
GPTMTnR=GPTMnMR
0xC350
0x411A
Time
TnEN set
TnPWML = 0
Output
Signal
TnPWML = 1
10.3
Initialization and Configuration
To use the general-purpose timers, the peripheral clock must be enabled by setting the TIMER0,
TIMER1, TIMER2, and TIMER3 bits in the RCGC1 register.
This section shows module initialization and configuration examples for each of the supported timer
modes.
10.3.1
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.
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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).
In One-Shot mode, the timer stops counting after step 7 on page 201. To re-enable the timer, repeat
the sequence. A timer configured in Periodic mode does not stop counting after it times out.
10.3.2
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 0x0000.0000 and begins counting. If an interrupt is enabled, it does not have to be cleared.
10.3.3
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).
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In One-Shot mode, the timer stops counting after step 8 on page 201. To re-enable the timer, repeat
the sequence. A timer configured in Periodic mode does not stop counting after it times out.
10.3.4
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.
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 step
4 on page 202-step 9 on page 202.
10.3.5
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
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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.
10.3.6
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.
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.
10.4
Register Map
Table 10-2 on page 203 lists the GPTM registers. The offset listed is a hexadecimal increment to the
register’s address, relative to that timer’s base address:
■ Timer0: 0x4003.0000
■ Timer1: 0x4003.1000
■ Timer2: 0x4003.2000
■ Timer3: 0x4003.3000
Table 10-2. Timers Register Map
Description
See
page
Offset
Name
Type
Reset
0x000
GPTMCFG
R/W
0x0000.0000
GPTM Configuration
205
0x004
GPTMTAMR
R/W
0x0000.0000
GPTM TimerA Mode
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Description
See
page
Offset
Name
Type
Reset
0x008
GPTMTBMR
R/W
0x0000.0000
GPTM TimerB Mode
208
0x00C
GPTMCTL
R/W
0x0000.0000
GPTM Control
210
0x018
GPTMIMR
R/W
0x0000.0000
GPTM Interrupt Mask
213
0x01C
GPTMRIS
RO
0x0000.0000
GPTM Raw Interrupt Status
215
0x020
GPTMMIS
RO
0x0000.0000
GPTM Masked Interrupt Status
216
0x024
GPTMICR
W1C
0x0000.0000
GPTM Interrupt Clear
217
0x028
GPTMTAILR
R/W
0x0000.FFFF
(16-bit mode)
0xFFFF.FFFF
(32-bit mode)
GPTM TimerA Interval Load
219
0x02C
GPTMTBILR
R/W
0x0000.FFFF
GPTM TimerB Interval Load
220
GPTM TimerA Match
221
0x030
GPTMTAMATCHR
R/W
0x0000.FFFF
(16-bit mode)
0xFFFF.FFFF
(32-bit mode)
0x034
GPTMTBMATCHR
R/W
0x0000.FFFF
GPTM TimerB Match
222
0x038
GPTMTAPR
R/W
0x0000.0000
GPTM TimerA Prescale
223
0x03C
GPTMTBPR
R/W
0x0000.0000
GPTM TimerB Prescale
224
0x040
GPTMTAPMR
R/W
0x0000.0000
GPTM TimerA Prescale Match
225
0x044
GPTMTBPMR
R/W
0x0000.0000
GPTM TimerB Prescale Match
226
GPTM TimerA
227
GPTM TimerB
228
0x048
GPTMTAR
RO
0x0000.FFFF
(16-bit mode)
0xFFFF.FFFF
(32-bit mode)
0x04C
GPTMTBR
RO
0x0000.FFFF
10.5
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
1
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
9
8
7
6
5
4
3
2
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
GPTMCFG
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:3
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
2:0
GPTMCFG
R/W
0x0
GPTM Configuration
The GPTMCFG values are defined as follows:
Value
Description
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x004
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
1
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
15
14
13
12
11
10
9
8
7
6
5
4
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
3
2
TAAMS
TACMR
R/W
0
R/W
0
0
TAMR
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:4
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
TAAMS
R/W
0
GPTM TimerA Alternate Mode Select
The TAAMS values are defined as follows:
Value Description
0
Capture mode is enabled.
1
PWM mode is enabled.
Note:
2
TACMR
R/W
0
To enable PWM mode, you must also clear the TACMR
bit and set the TAMR field to 0x2.
GPTM TimerA Capture Mode
The TACMR values are defined as follows:
Value Description
0
Edge-Count mode.
1
Edge-Time mode.
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Bit/Field
Name
Type
Reset
1:0
TAMR
R/W
0x0
Description
GPTM TimerA Mode
The TAMR values are defined as follows:
Value Description
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
1
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
15
14
13
12
11
10
9
8
7
6
5
4
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
3
2
TBAMS
TBCMR
R/W
0
R/W
0
0
TBMR
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:4
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
TBAMS
R/W
0
GPTM TimerB Alternate Mode Select
The TBAMS values are defined as follows:
Value Description
0
Capture mode is enabled.
1
PWM mode is enabled.
Note:
2
TBCMR
R/W
0
To enable PWM mode, you must also clear the TBCMR
bit and set the TBMR field to 0x2.
GPTM TimerB Capture Mode
The TBCMR values are defined as follows:
Value Description
0
Edge-Count mode.
1
Edge-Time mode.
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Bit/Field
Name
Type
Reset
1:0
TBMR
R/W
0x0
Description
GPTM TimerB Mode
The TBMR values are defined as follows:
Value Description
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.
GPTM Control (GPTMCTL)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x00C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
3
2
reserved
Type
Reset
RO
0
RO
0
RO
0
15
14
13
reserved TBPWML TBOTE
Type
Reset
RO
0
R/W
0
RO
0
RO
0
RO
0
12
11
10
reserved
R/W
0
RO
0
TBEVENT
R/W
0
R/W
0
RO
0
RO
0
9
8
TBSTALL
TBEN
R/W
0
R/W
0
reserved TAPWML
RO
0
R/W
0
5
4
TAOTE
RTCEN
R/W
0
R/W
0
TAEVENT
R/W
0
R/W
0
1
0
TASTALL
TAEN
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:15
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
14
TBPWML
R/W
0
GPTM TimerB PWM Output Level
The TBPWML values are defined as follows:
Value Description
13
TBOTE
R/W
0
0
Output is unaffected.
1
Output is inverted.
GPTM TimerB Output Trigger Enable
The TBOTE values are defined as follows:
Value Description
12
reserved
RO
0
11:10
TBEVENT
R/W
0x0
0
The output TimerB trigger is disabled.
1
The output TimerB trigger is enabled.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPTM TimerB Event Mode
The TBEVENT values are defined as follows:
Value Description
0x0 Positive edge.
0x1 Negative edge.
0x2 Reserved
0x3 Both edges.
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Bit/Field
Name
Type
Reset
9
TBSTALL
R/W
0
Description
GPTM TimerB Stall Enable
The TBSTALL values are defined as follows:
Value Description
8
TBEN
R/W
0
0
TimerB stalling is disabled.
1
TimerB stalling is enabled.
GPTM TimerB Enable
The TBEN values are defined as follows:
Value Description
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
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
TAPWML
R/W
0
GPTM TimerA PWM Output Level
The TAPWML values are defined as follows:
Value Description
5
TAOTE
R/W
0
0
Output is unaffected.
1
Output is inverted.
GPTM TimerA Output Trigger Enable
The TAOTE values are defined as follows:
Value Description
4
RTCEN
R/W
0
0
The output TimerA trigger is disabled.
1
The output TimerA trigger is enabled.
GPTM RTC Enable
The RTCEN values are defined as follows:
Value Description
0
RTC counting is disabled.
1
RTC counting is enabled.
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Bit/Field
Name
Type
Reset
3:2
TAEVENT
R/W
0x0
Description
GPTM TimerA Event Mode
The TAEVENT values are defined as follows:
Value Description
0x0 Positive edge.
0x1 Negative edge.
0x2 Reserved
0x3 Both edges.
1
TASTALL
R/W
0
GPTM TimerA Stall Enable
The TASTALL values are defined as follows:
Value Description
0
TAEN
R/W
0
0
TimerA stalling is disabled.
1
TimerA stalling is enabled.
GPTM TimerA Enable
The TAEN values are defined as follows:
Value Description
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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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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x018
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
15
14
RO
0
RO
0
RO
0
13
12
11
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
7
6
5
4
10
9
8
CBEIM
CBMIM
TBTOIM
R/W
0
R/W
0
R/W
0
reserved
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RTCIM
CAEIM
CAMIM
TATOIM
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
CBEIM
R/W
0
GPTM CaptureB Event Interrupt Mask
The CBEIM values are defined as follows:
Value Description
9
CBMIM
R/W
0
0
Interrupt is disabled.
1
Interrupt is enabled.
GPTM CaptureB Match Interrupt Mask
The CBMIM values are defined as follows:
Value Description
8
TBTOIM
R/W
0
0
Interrupt is disabled.
1
Interrupt is enabled.
GPTM TimerB Time-Out Interrupt Mask
The TBTOIM values are defined as follows:
Value Description
7:4
reserved
RO
0
0
Interrupt is disabled.
1
Interrupt is enabled.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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Bit/Field
Name
Type
Reset
3
RTCIM
R/W
0
Description
GPTM RTC Interrupt Mask
The RTCIM values are defined as follows:
Value Description
2
CAEIM
R/W
0
0
Interrupt is disabled.
1
Interrupt is enabled.
GPTM CaptureA Event Interrupt Mask
The CAEIM values are defined as follows:
Value Description
1
CAMIM
R/W
0
0
Interrupt is disabled.
1
Interrupt is enabled.
GPTM CaptureA Match Interrupt Mask
The CAMIM values are defined as follows:
Value Description
0
TATOIM
R/W
0
0
Interrupt is disabled.
1
Interrupt is enabled.
GPTM TimerA Time-Out Interrupt Mask
The TATOIM values are defined as follows:
Value Description
0
Interrupt is disabled.
1
Interrupt is enabled.
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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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x01C
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
2
1
0
reserved
Type
Reset
RO
0
RO
0
15
14
RO
0
RO
0
RO
0
13
12
11
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
10
9
8
7
6
5
4
CBERIS CBMRIS TBTORIS
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
RO
0
RO
0
RO
0
3
RTCRIS
RO
0
RO
0
CAERIS CAMRIS TATORIS
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
CBERIS
RO
0
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
reserved
RO
0x0
3
RTCRIS
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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.
October 09, 2007
215
Preliminary
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x020
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
reserved
Type
Reset
RO
0
RO
0
15
14
RO
0
RO
0
RO
0
13
12
11
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
10
9
8
7
6
5
4
CBEMIS CBMMIS TBTOMIS
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
RO
0
RO
0
RO
0
RTCMIS CAEMIS CAMMIS TATOMIS
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
CBEMIS
RO
0
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
reserved
RO
0x0
3
RTCMIS
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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.
216
October 09, 2007
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LM3S1911 Microcontroller
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x024
Type W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
reserved
Type
Reset
RO
0
RO
0
15
14
RO
0
RO
0
RO
0
13
12
11
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
10
9
8
7
6
5
4
CBECINT CBMCINT TBTOCINT
RO
0
RO
0
W1C
0
W1C
0
W1C
0
reserved
RO
0
RO
0
RO
0
RTCCINT CAECINT CAMCINT TATOCINT
RO
0
W1C
0
W1C
0
W1C
0
W1C
0
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
CBECINT
W1C
0
GPTM CaptureB Event Interrupt Clear
The CBECINT values are defined as follows:
Value Description
9
CBMCINT
W1C
0
0
The interrupt is unaffected.
1
The interrupt is cleared.
GPTM CaptureB Match Interrupt Clear
The CBMCINT values are defined as follows:
Value Description
8
TBTOCINT
W1C
0
0
The interrupt is unaffected.
1
The interrupt is cleared.
GPTM TimerB Time-Out Interrupt Clear
The TBTOCINT values are defined as follows:
Value Description
7:4
reserved
RO
0x0
0
The interrupt is unaffected.
1
The interrupt is cleared.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
217
Preliminary
General-Purpose Timers
Bit/Field
Name
Type
Reset
3
RTCCINT
W1C
0
Description
GPTM RTC Interrupt Clear
The RTCCINT values are defined as follows:
Value Description
2
CAECINT
W1C
0
0
The interrupt is unaffected.
1
The interrupt is cleared.
GPTM CaptureA Event Interrupt Clear
The CAECINT values are defined as follows:
Value Description
1
CAMCINT
W1C
0
0
The interrupt is unaffected.
1
The interrupt is cleared.
GPTM CaptureA Match Raw Interrupt
This is the CaptureA match interrupt status after masking.
0
TATOCINT
W1C
0
GPTM TimerA Time-Out Raw Interrupt
The TATOCINT values are defined as follows:
Value Description
0
The interrupt is unaffected.
1
The interrupt is cleared.
218
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x028
Type R/W, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
TAILRH
Type
Reset
R/W
0
R/W
1
R/W
1
R/W
0
R/W
1
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
TAILRL
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:16
TAILRH
R/W
R/W
1
R/W
1
Reset
R/W
1
Description
0xFFFF
GPTM TimerA Interval Load Register High
(32-bit mode)
0x0000 (16-bit When configured for 32-bit mode via the GPTMCFG register, the GPTM
TimerB Interval Load (GPTMTBILR) register loads this value on a
mode)
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.
15:0
TAILRL
R/W
0xFFFF
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.
October 09, 2007
219
Preliminary
General-Purpose Timers
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x02C
Type R/W, reset 0x0000.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
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
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15:0
TBILRL
R/W
0xFFFF
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.
220
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x030
Type R/W, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
TAMRH
Type
Reset
R/W
0
R/W
1
R/W
1
R/W
0
R/W
1
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
TAMRL
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:16
TAMRH
R/W
R/W
1
R/W
1
Reset
R/W
1
Description
0xFFFF
GPTM TimerA Match Register High
(32-bit mode)
0x0000 (16-bit When configured for 32-bit Real-Time Clock (RTC) mode via the
GPTMCFG register, this value is compared to the upper half of
mode)
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.
15:0
TAMRL
R/W
0xFFFF
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.
October 09, 2007
221
Preliminary
General-Purpose Timers
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x034
Type R/W, reset 0x0000.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
TBMRL
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
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15:0
TBMRL
R/W
0xFFFF
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.
222
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 13: GPTM TimerA Prescale (GPTMTAPR), offset 0x038
This register allows software to extend the range of the 16-bit timers when operating in one-shot or
periodic mode.
GPTM TimerA Prescale (GPTMTAPR)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x038
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
TAPSR
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
TAPSR
R/W
0x00
GPTM TimerA Prescale
The register loads this value on a write. A read returns the current value
of the register.
Refer to Table 10-1 on page 197 for more details and an example.
October 09, 2007
223
Preliminary
General-Purpose Timers
Register 14: GPTM TimerB Prescale (GPTMTBPR), offset 0x03C
This register allows software to extend the range of the 16-bit timers when operating in one-shot or
periodic mode.
GPTM TimerB Prescale (GPTMTBPR)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x03C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
TBPSR
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
TBPSR
R/W
0x00
GPTM TimerB Prescale
The register loads this value on a write. A read returns the current value
of this register.
Refer to Table 10-1 on page 197 for more details and an example.
224
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 15: GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040
This register effectively extends the range of GPTMTAMATCHR to 24 bits when operating in 16-bit
one-shot or periodic mode.
GPTM TimerA Prescale Match (GPTMTAPMR)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x040
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
TAPSMR
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
TAPSMR
R/W
0x00
GPTM TimerA Prescale Match
This value is used alongside GPTMTAMATCHR to detect timer match
events while using a prescaler.
October 09, 2007
225
Preliminary
General-Purpose Timers
Register 16: GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044
This register effectively extends the range of GPTMTBMATCHR to 24 bits when operating in 16-bit
one-shot or periodic mode.
GPTM TimerB Prescale Match (GPTMTBPMR)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x044
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
TBPSMR
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
TBPSMR
R/W
0x00
GPTM TimerB Prescale Match
This value is used alongside GPTMTBMATCHR to detect timer match
events while using a prescaler.
226
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x048
Type RO, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
1
RO
1
RO
0
RO
1
RO
1
RO
1
RO
1
RO
0
7
6
5
4
3
2
1
0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
TARH
Type
Reset
RO
0
RO
1
RO
1
RO
0
RO
1
RO
0
RO
1
RO
1
15
14
13
12
11
10
9
8
TARL
Type
Reset
RO
1
RO
1
RO
1
RO
1
RO
1
Bit/Field
Name
Type
31:16
TARH
RO
15:0
TARL
RO
RO
1
RO
1
Reset
RO
1
Description
0xFFFF
GPTM TimerA Register High
(32-bit mode)
0x0000 (16-bit 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.
mode)
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.
October 09, 2007
227
Preliminary
General-Purpose Timers
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)
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
Offset 0x04C
Type RO, reset 0x0000.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
TBRL
Type
Reset
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15:0
TBRL
RO
0xFFFF
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.
228
October 09, 2007
Preliminary
LM3S1911 Microcontroller
11
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.
11.1
Block Diagram
Figure 11-1. WDT Module Block Diagram
WDTLOAD
Control / Clock /
Interrupt
Generation
WDTCTL
WDTICR
Interrupt
WDTRIS
32-Bit Down
Counter
WDTMIS
0x00000000
WDTLOCK
System Clock
WDTTEST
Comparator
WDTVALUE
Identification Registers
11.2
WDTPCellID0
WDTPeriphID0
WDTPeriphID4
WDTPCellID1
WDTPeriphID1
WDTPeriphID5
WDTPCellID2
WDTPeriphID2
WDTPeriphID6
WDTPCellID3
WDTPeriphID3
WDTPeriphID7
Functional Description
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. Once the
October 09, 2007
229
Preliminary
Watchdog Timer
Watchdog Timer has been configured, the Watchdog Timer Lock (WDTLOCK) register is written,
which prevents the timer configuration from being inadvertently altered by software.
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.
11.3
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 0x1ACC.E551.
11.4
Register Map
Table 11-1 on page 230 lists the Watchdog registers. The offset listed is a hexadecimal increment
to the register’s address, relative to the Watchdog Timer base address of 0x4000.0000.
Table 11-1. Watchdog Timer Register Map
Description
See
page
Offset
Name
Type
Reset
0x000
WDTLOAD
R/W
0xFFFF.FFFF
Watchdog Load
232
0x004
WDTVALUE
RO
0xFFFF.FFFF
Watchdog Value
233
0x008
WDTCTL
R/W
0x0000.0000
Watchdog Control
234
0x00C
WDTICR
WO
-
Watchdog Interrupt Clear
235
0x010
WDTRIS
RO
0x0000.0000
Watchdog Raw Interrupt Status
236
0x014
WDTMIS
RO
0x0000.0000
Watchdog Masked Interrupt Status
237
0x418
WDTTEST
R/W
0x0000.0000
Watchdog Test
238
0xC00
WDTLOCK
R/W
0x0000.0000
Watchdog Lock
239
230
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Offset
Name
0xFD0
Reset
WDTPeriphID4
RO
0x0000.0000
Watchdog Peripheral Identification 4
240
0xFD4
WDTPeriphID5
RO
0x0000.0000
Watchdog Peripheral Identification 5
241
0xFD8
WDTPeriphID6
RO
0x0000.0000
Watchdog Peripheral Identification 6
242
0xFDC
WDTPeriphID7
RO
0x0000.0000
Watchdog Peripheral Identification 7
243
0xFE0
WDTPeriphID0
RO
0x0000.0005
Watchdog Peripheral Identification 0
244
0xFE4
WDTPeriphID1
RO
0x0000.0018
Watchdog Peripheral Identification 1
245
0xFE8
WDTPeriphID2
RO
0x0000.0018
Watchdog Peripheral Identification 2
246
0xFEC
WDTPeriphID3
RO
0x0000.0001
Watchdog Peripheral Identification 3
247
0xFF0
WDTPCellID0
RO
0x0000.000D
Watchdog PrimeCell Identification 0
248
0xFF4
WDTPCellID1
RO
0x0000.00F0
Watchdog PrimeCell Identification 1
249
0xFF8
WDTPCellID2
RO
0x0000.0005
Watchdog PrimeCell Identification 2
250
0xFFC
WDTPCellID3
RO
0x0000.00B1
Watchdog PrimeCell Identification 3
251
11.5
Description
See
page
Type
Register Descriptions
The remainder of this section lists and describes the WDT registers, in numerical order by address
offset.
October 09, 2007
231
Preliminary
Watchdog Timer
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 0x0000.0000, an interrupt is immediately generated.
Watchdog Load (WDTLOAD)
Base 0x4000.0000
Offset 0x000
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
15
14
13
12
11
10
9
8
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
23
22
21
20
19
18
17
16
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
WDTLoad
Type
Reset
WDTLoad
Type
Reset
Bit/Field
Name
Type
31:0
WDTLoad
R/W
Reset
R/W
1
Description
0xFFFF.FFFF Watchdog Load Value
232
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 2: Watchdog Value (WDTVALUE), offset 0x004
This register contains the current count value of the timer.
Watchdog Value (WDTVALUE)
Base 0x4000.0000
Offset 0x004
Type RO, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
15
14
13
12
11
10
9
8
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
23
22
21
20
19
18
17
16
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
7
6
5
4
3
2
1
0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
WDTValue
Type
Reset
WDTValue
Type
Reset
Bit/Field
Name
Type
31:0
WDTValue
RO
Reset
RO
1
Description
0xFFFF.FFFF Watchdog Value
Current value of the 32-bit down counter.
October 09, 2007
233
Preliminary
Watchdog Timer
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 (on 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)
Base 0x4000.0000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
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
1
0
RESEN
INTEN
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
RESEN
R/W
0
Watchdog Reset Enable
The RESEN values are defined as follows:
Value Description
0
INTEN
R/W
0
0
Disabled.
1
Enable the Watchdog module reset output.
Watchdog Interrupt Enable
The INTEN values are defined as follows:
Value Description
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.
234
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0x00C
Type WO, reset 31
30
29
28
27
26
25
24
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
15
14
13
12
11
10
9
8
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
23
22
21
20
19
18
17
16
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
7
6
5
4
3
2
1
0
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WDTIntClr
Type
Reset
WDTIntClr
Type
Reset
Bit/Field
Name
Type
Reset
31:0
WDTIntClr
WO
-
WO
-
Description
Watchdog Interrupt Clear
October 09, 2007
235
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0x010
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
WDTRIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
WDTRIS
RO
0
Watchdog Raw Interrupt Status
Gives the raw interrupt state (prior to masking) of WDTINTR.
236
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0x014
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
WDTMIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
WDTMIS
RO
0
Watchdog Masked Interrupt Status
Gives the masked interrupt state (after masking) of the WDTINTR
interrupt.
October 09, 2007
237
Preliminary
Watchdog Timer
Register 7: Watchdog Test (WDTTEST), offset 0x418
This register provides user-enabled stalling when the microcontroller asserts the CPU halt flag
during debug.
Watchdog Test (WDTTEST)
Base 0x4000.0000
Offset 0x418
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
STALL
R/W
0
reserved
Bit/Field
Name
Type
Reset
Description
31:9
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
8
STALL
R/W
0
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
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
238
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 8: Watchdog Lock (WDTLOCK), offset 0xC00
Writing 0x1ACC.E551 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
0x0000.0001 (when locked; otherwise, the returned value is 0x0000.0000 (unlocked)).
Watchdog Lock (WDTLOCK)
Base 0x4000.0000
Offset 0xC00
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
15
14
13
12
11
10
9
8
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
23
22
21
20
19
18
17
16
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
7
6
5
4
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
WDTLock
Type
Reset
WDTLock
Type
Reset
Bit/Field
Name
Type
Reset
31:0
WDTLock
R/W
0x0000
R/W
0
Description
Watchdog Lock
A write of the value 0x1ACC.E551 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:
Value
Description
0x0000.0001 Locked
0x0000.0000 Unlocked
October 09, 2007
239
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0xFD0
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID4
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID4
RO
0x00
WDT Peripheral ID Register[7:0]
240
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0xFD4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID5
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID5
RO
0x00
WDT Peripheral ID Register[15:8]
October 09, 2007
241
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0xFD8
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID6
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID6
RO
0x00
WDT Peripheral ID Register[23:16]
242
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0xFDC
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID7
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID7
RO
0x00
WDT Peripheral ID Register[31:24]
October 09, 2007
243
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0xFE0
Type RO, reset 0x0000.0005
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
1
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID0
RO
0x05
Watchdog Peripheral ID Register[7:0]
244
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0xFE4
Type RO, reset 0x0000.0018
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
1
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID1
RO
0x18
Watchdog Peripheral ID Register[15:8]
October 09, 2007
245
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0xFE8
Type RO, reset 0x0000.0018
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
1
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID2
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID2
RO
0x18
Watchdog Peripheral ID Register[23:16]
246
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0xFEC
Type RO, reset 0x0000.0001
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
1
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
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID3
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID3
RO
0x01
Watchdog Peripheral ID Register[31:24]
October 09, 2007
247
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0xFF0
Type RO, reset 0x0000.000D
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID0
RO
0x0D
Watchdog PrimeCell ID Register[7:0]
248
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0xFF4
Type RO, reset 0x0000.00F0
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
1
RO
1
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
CID1
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID1
RO
0xF0
Watchdog PrimeCell ID Register[15:8]
October 09, 2007
249
Preliminary
Watchdog Timer
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)
Base 0x4000.0000
Offset 0xFF8
Type RO, reset 0x0000.0005
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID2
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID2
RO
0x05
Watchdog PrimeCell ID Register[23:16]
250
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
Base 0x4000.0000
Offset 0xFFC
Type RO, reset 0x0000.00B1
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
1
RO
0
RO
1
RO
1
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID3
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID3
RO
0xB1
Watchdog PrimeCell ID Register[31:24]
October 09, 2007
251
Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
12
Universal Asynchronous Receivers/Transmitters
(UARTs)
®
The Stellaris Universal Asynchronous Receiver/Transmitter (UART) provides fully programmable,
16C550-type serial interface characteristics. The LM3S1911 controller is equipped with three UART
modules.
Each 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 3.125 Mbps
■ 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
■ IrDA serial-IR (SIR) encoder/decoder providing:
– Programmable use of IrDA Serial InfraRed (SIR) or UART input/output
– Support of IrDA SIR encoder/decoder functions for data rates up to 115.2 Kbps half-duplex
– Support of normal 3/16 and low-power (1.41-2.23 μs) bit durations
– Programmable internal clock generator enabling division of reference clock by 1 to 256 for
low-power mode bit duration
252
October 09, 2007
Preliminary
LM3S1911 Microcontroller
12.1
Block Diagram
Figure 12-1. UART Module Block Diagram
System Clock
Interrupt Control
Interrupt
TXFIFO
16x8
UARTIFLS
.
.
.
UARTIM
UARTMIS
UARTRIS
Identification
Registers
UARTICR
Transmitter
UnTx
Receiver
UnRx
UARTPCellID0
UARTPCellID1
Baud Rate
Generator
UARTDR
UARTPCellID2
UARTIBRD
UARTPCellID3
UARTFBRD
UARTPeriphID0
UARTPeriphID1
UARTPeriphID2
UARTPeriphID3
Control / Status
UART PeriphID4
UARTRSR/ECR
UARTPeriphID5
RXFIFO
16x8
UARTFR
UARTPeriphID6
UARTLCRH
UARTPeriphID7
UARTCTL
UARTILPR
12.2
.
.
.
Functional Description
®
Each 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 271). 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.
The UART peripheral also includes a serial IR (SIR) encoder/decoder block that can be connected
to an infrared transceiver to implement an IrDA SIR physical layer. The SIR function is programmed
using the UARTCTL register.
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
October 09, 2007
253
Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
bits (LSB first), parity bit, and the stop bits according to the programmed configuration in the control
registers. See Figure 12-2 on page 254 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
LSB
1
5-8 data bits
0
n
Start
12.2.2
1-2
stop bits
MSB
Parity bit
if enabled
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 267) and the 6-bit fractional part is loaded with the UART Fractional Baud-Rate Divisor
(UARTFBRD) register (see page 268). 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 269), 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
254
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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 264) 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 (the UnRx 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 253).
The start bit is valid if UnRx 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 262). 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 UnRx 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
Serial IR (SIR)
The UART peripheral includes an IrDA serial-IR (SIR) encoder/decoder block. The IrDA SIR block
provides functionality that converts between an asynchronous UART data stream, and half-duplex
serial SIR interface. No analog processing is performed on-chip. The role of the SIR block is to
provide a digital encoded output, and decoded input to the UART. The UART signal pins can be
connected to an infrared transceiver to implement an IrDA SIR physical layer link. The SIR block
has two modes of operation:
■ In normal IrDA mode, a zero logic level is transmitted as high pulse of 3/16th duration of the
selected baud rate bit period on the output pin, while logic one levels are transmitted as a static
LOW signal. These levels control the driver of an infrared transmitter, sending a pulse of light
for each zero. On the reception side, the incoming light pulses energize the photo transistor base
of the receiver, pulling its output LOW. This drives the UART input pin LOW.
■ In low-power IrDA mode, the width of the transmitted infrared pulse is set to three times the
period of the internally generated IrLPBaud16 signal (1.63 µs, assuming a nominal 1.8432 MHz
frequency) by changing the appropriate bit in the UARTCR register.
Figure 12-3 on page 256 shows the UART transmit and receive signals, with and without IrDA
modulation.
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Figure 12-3. IrDA Data Modulation
Data bits
Start
bit
UnTx
1
0
0
0
1
Stop
bit
0
0
1
1
1
UnTx with IrDA
3
16 Bit period
Bit period
UnRx with IrDA
UnRx
0
1
0
1
Start
0
0
1
1
0
Data bits
1
Stop
In both normal and low-power IrDA modes:
■ During transmission, the UART data bit is used as the base for encoding
■ During reception, the decoded bits are transferred to the UART receive logic
The IrDA SIR physical layer specifies a half-duplex communication link, with a minimum 10 ms delay
between transmission and reception. This delay must be generated by software because it is not
automatically supported by the UART. The delay is required because the infrared receiver electronics
might become biased, or even saturated from the optical power coupled from the adjacent transmitter
LED. This delay is known as latency, or receiver setup time.
12.2.5
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 260). 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 269).
FIFO status can be monitored via the UART Flag (UARTFR) register (see page 264) 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 273). Both FIFOs can be individually configured to
trigger interrupts at different levels. Available configurations include 1/8, ¼, ½, ¾, and 7/8. For
example, if the ¼ 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
½ mark.
12.2.6
Interrupts
The UART can generate interrupts when the following conditions are observed:
■ Overrun Error
■ Break Error
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■ Parity Error
■ Framing Error
■ 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 278).
The interrupt events that can trigger a controller-level interrupt are defined in the UART Interrupt
Mask (UARTIM ) register (see page 275) 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 277).
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 279).
The receive timeout interrupt is asserted when the receive FIFO is not empty, and no further data
is received over a 32-bit period. The receive timeout interrupt is cleared either when the FIFO
becomes empty through reading all the data (or by reading the holding register), or when a 1 is
written to the corresponding bit in the UARTICR register.
12.2.7
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 271). In loopback mode,
data transmitted on UnTx is received on the UnRx input.
12.2.8
IrDA SIR block
The IrDA SIR block contains an IrDA serial IR (SIR) protocol encoder/decoder. When enabled, the
SIR block uses the UnTx and UnRx pins for the SIR protocol, which should be connected to an IR
transceiver.
The SIR block can receive and transmit, but it is only half-duplex so it cannot do both at the same
time. Transmission must be stopped before data can be received. The IrDA SIR physical layer
specifies a minimum 10-ms delay between transmission and reception.
12.3
Initialization and Configuration
To use the UARTs, the peripheral clock must be enabled by setting the UART0, UART1, or UART2
bits 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
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■ 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 254, 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 267) should be set to 10.
The value to be loaded into the UARTFBRD register (see page 268) 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.
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
0x0000.0060).
5. Enable the UART by setting the UARTEN bit in the UARTCTL register.
12.4
Register Map
Table 12-1 on page 258 lists the UART registers. The offset listed is a hexadecimal increment to the
register’s address, relative to that UART’s base address:
■ UART0: 0x4000.C000
■ UART1: 0x4000.D000
■ UART2: 0x4000.E000
Note:
The UART must be disabled (see the UARTEN bit in the UARTCTL register on page 271)
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. UART Register Map
Offset
Name
Type
Reset
Description
See
page
0x000
UARTDR
R/W
0x0000.0000
UART Data
260
0x004
UARTRSR/UARTECR
R/W
0x0000.0000
UART Receive Status/Error Clear
262
0x018
UARTFR
RO
0x0000.0090
UART Flag
264
0x020
UARTILPR
R/W
0x0000.0000
UART IrDA Low-Power Register
266
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Name
Type
Reset
0x024
UARTIBRD
R/W
0x0000.0000
UART Integer Baud-Rate Divisor
267
0x028
UARTFBRD
R/W
0x0000.0000
UART Fractional Baud-Rate Divisor
268
0x02C
UARTLCRH
R/W
0x0000.0000
UART Line Control
269
0x030
UARTCTL
R/W
0x0000.0300
UART Control
271
0x034
UARTIFLS
R/W
0x0000.0012
UART Interrupt FIFO Level Select
273
0x038
UARTIM
R/W
0x0000.0000
UART Interrupt Mask
275
0x03C
UARTRIS
RO
0x0000.000F
UART Raw Interrupt Status
277
0x040
UARTMIS
RO
0x0000.0000
UART Masked Interrupt Status
278
0x044
UARTICR
W1C
0x0000.0000
UART Interrupt Clear
279
0xFD0
UARTPeriphID4
RO
0x0000.0000
UART Peripheral Identification 4
281
0xFD4
UARTPeriphID5
RO
0x0000.0000
UART Peripheral Identification 5
282
0xFD8
UARTPeriphID6
RO
0x0000.0000
UART Peripheral Identification 6
283
0xFDC
UARTPeriphID7
RO
0x0000.0000
UART Peripheral Identification 7
284
0xFE0
UARTPeriphID0
RO
0x0000.0011
UART Peripheral Identification 0
285
0xFE4
UARTPeriphID1
RO
0x0000.0000
UART Peripheral Identification 1
286
0xFE8
UARTPeriphID2
RO
0x0000.0018
UART Peripheral Identification 2
287
0xFEC
UARTPeriphID3
RO
0x0000.0001
UART Peripheral Identification 3
288
0xFF0
UARTPCellID0
RO
0x0000.000D
UART PrimeCell Identification 0
289
0xFF4
UARTPCellID1
RO
0x0000.00F0
UART PrimeCell Identification 1
290
0xFF8
UARTPCellID2
RO
0x0000.0005
UART PrimeCell Identification 2
291
0xFFC
UARTPCellID3
RO
0x0000.00B1
UART PrimeCell Identification 3
292
12.5
Description
See
page
Offset
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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
OE
BE
PE
FE
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
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
reserved
Type
Reset
reserved
Type
Reset
RO
0
DATA
Bit/Field
Name
Type
Reset
Description
31:12
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
11
OE
RO
0
UART Overrun Error
The OE values are defined as follows:
Value Description
10
BE
RO
0
0
There has been no data loss due to a FIFO overrun.
1
New data was received when the FIFO was full, resulting in
data loss.
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 full-word
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.
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Bit/Field
Name
Type
Reset
9
PE
RO
0
Description
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.
8
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).
7:0
DATA
R/W
0
Data Transmitted or Received
When written, the data that is to be transmitted via the UART. When
read, the data that was received by the UART.
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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.
Read-Only Receive Status (UARTRSR) Register
UART Receive Status/Error Clear (UARTRSR/UARTECR)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x004
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
OE
BE
PE
FE
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
31:4
reserved
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
The UARTRSR register cannot be written.
3
OE
RO
0
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.
2
BE
RO
0
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 full-word
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.
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Bit/Field
Name
Type
Reset
1
PE
RO
0
Description
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
UART Receive Status/Error Clear (UARTRSR/UARTECR)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x004
Type WO, reset 0x0000.0000
31
30
29
28
27
26
25
24
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
15
14
13
12
11
10
9
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
23
22
21
20
19
18
17
16
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
8
7
6
5
4
3
2
1
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
reserved
Type
Reset
reserved
Type
Reset
DATA
WO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
WO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DATA
WO
0
Error Clear
A write to this register of any data clears the framing, parity, break, and
overrun flags.
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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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x018
Type RO, reset 0x0000.0090
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
TXFE
RXFF
TXFF
RXFE
BUSY
RO
1
RO
0
RO
0
RO
1
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
reserved
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
TXFE
RO
1
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.
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Bit/Field
Name
Type
Reset
4
RXFE
RO
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
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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Register 4: UART IrDA Low-Power Register (UARTILPR), offset 0x020
The UARTILPR register is an 8-bit read/write register that stores the low-power counter divisor
value used to generate the IrLPBaud16 signal by dividing down the system clock (SysClk). All the
bits are cleared to 0 when reset.
The IrLPBaud16 internal signal is generated by dividing down the UARTCLK signal according to
the low-power divisor value written to UARTILPR. The low-power divisor value is calculated as
follows:
ILPDVSR = SysClk / FIrLPBaud16
where FIrLPBaud16 is nominally 1.8432 MHz.
IrLPBaud16 is an internal signal used for SIR pulse generation when low-power mode is used.
You must choose the divisor so that 1.42 MHz < FIrLPBaud16 < 2.12 MHz, which results in a low-power
pulse duration of 1.41–2.11 μs (three times the period of IrLPBaud16). The minimum frequency
of IrLPBaud16 ensures that pulses less than one period of IrLPBaud16 are rejected, but that
pulses greater than 1.4 μs are accepted as valid pulses.
Note:
Zero is an illegal value. Programming a zero value results in no IrLPBaud16 pulses being
generated.
UART IrDA Low-Power Register (UARTILPR)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x020
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
ILPDVSR
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0
7:0
ILPDVSR
R/W
0x00
R/W
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
IrDA Low-Power Divisor
This is an 8-bit low-power divisor value.
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Preliminary
LM3S1911 Microcontroller
Register 5: 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 254
for configuration details.
UART Integer Baud-Rate Divisor (UARTIBRD)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x024
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
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
reserved
Type
Reset
DIVINT
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0
15:0
DIVINT
R/W
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Integer Baud-Rate Divisor
October 09, 2007
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Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 6: 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 254
for configuration details.
UART Fractional Baud-Rate Divisor (UARTFBRD)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x028
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
DIVFRAC
R/W
0
Bit/Field
Name
Type
Reset
Description
31:6
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5:0
DIVFRAC
R/W
0x000
Fractional Baud-Rate Divisor
268
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 7: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x02C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
SPS
RO
0
RO
0
RO
0
RO
0
R/W
0
5
WLEN
R/W
0
R/W
0
4
3
2
1
0
FEN
STP2
EPS
PEN
BRK
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7
SPS
R/W
0
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:
Value Description
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.
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Universal Asynchronous Receivers/Transmitters (UARTs)
Bit/Field
Name
Type
Reset
3
STP2
R/W
0
Description
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.
2
EPS
R/W
0
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.
270
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 8: 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 (UARTCTL)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x030
Type R/W, reset 0x0000.0300
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
6
5
4
3
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
9
8
7
RXE
TXE
LBE
R/W
1
R/W
1
R/W
0
reserved
RO
0
RO
0
RO
0
RO
0
2
1
0
SIRLP
SIREN
UARTEN
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:10
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
9
RXE
R/W
1
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.
Note:
8
TXE
R/W
1
To enable reception, the UARTEN bit must also be set.
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.
Note:
7
LBE
R/W
0
To enable transmission, the UARTEN bit must also be set.
UART Loop Back Enable
If this bit is set to 1, the UnTX path is fed through the UnRX path.
6:3
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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Universal Asynchronous Receivers/Transmitters (UARTs)
Bit/Field
Name
Type
Reset
2
SIRLP
R/W
0
Description
UART SIR Low Power Mode
This bit selects the IrDA encoding mode. If this bit is cleared to 0,
low-level bits are transmitted as an active High pulse with a width of
3/16th of the bit period. If this bit is set to 1, low-level bits are transmitted
with a pulse width which is 3 times the period of the IrLPBaud16 input
signal, regardless of the selected bit rate. Setting this bit uses less power,
but might reduce transmission distances. See page 266 for more
information.
1
SIREN
R/W
0
UART SIR Enable
If this bit is set to 1, the IrDA SIR block is enabled, and the UART will
transmit and receive data using SIR protocol.
0
UARTEN
R/W
0
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.
272
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 9: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x034
Type R/W, reset 0x0000.0012
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
RXIFLSEL
R/W
1
TXIFLSEL
R/W
1
R/W
0
Bit/Field
Name
Type
Reset
Description
31:6
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5:3
RXIFLSEL
R/W
0x2
UART Receive Interrupt FIFO Level Select
The trigger points for the receive interrupt are as follows:
Value
Description
0x0
RX FIFO ≥ 1/8 full
0x1
RX FIFO ≥ ¼ full
0x2
RX FIFO ≥ ½ full (default)
0x3
RX FIFO ≥ ¾ full
0x4
RX FIFO ≥ 7/8 full
0x5-0x7 Reserved
October 09, 2007
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Universal Asynchronous Receivers/Transmitters (UARTs)
Bit/Field
Name
Type
Reset
2:0
TXIFLSEL
R/W
0x2
Description
UART Transmit Interrupt FIFO Level Select
The trigger points for the transmit interrupt are as follows:
Value
Description
0x0
TX FIFO ≤ 1/8 full
0x1
TX FIFO ≤ ¼ full
0x2
TX FIFO ≤ ½ full (default)
0x3
TX FIFO ≤ ¾ full
0x4
TX FIFO ≤ 7/8 full
0x5-0x7 Reserved
274
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 10: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x038
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
15
14
RO
0
RO
0
RO
0
13
12
11
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
10
9
8
7
6
5
4
OEIM
BEIM
PEIM
FEIM
RTIM
TXIM
RXIM
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
OEIM
R/W
0
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.
5
TXIM
R/W
0
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.
October 09, 2007
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Universal Asynchronous Receivers/Transmitters (UARTs)
Bit/Field
Name
Type
Reset
4
RXIM
R/W
0
Description
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
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
276
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 11: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x03C
Type RO, reset 0x0000.000F
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
OERIS
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
BERIS
PERIS
FERIS
RTRIS
TXRIS
RXRIS
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
1
RO
1
reserved
Type
Reset
reserved
Type
Reset
RO
0
reserved
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
OERIS
RO
0
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
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
October 09, 2007
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Universal Asynchronous Receivers/Transmitters (UARTs)
Register 12: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x040
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
OEMIS
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
BEMIS
PEMIS
FEMIS
RTMIS
TXMIS
RXMIS
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
reserved
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
OEMIS
RO
0
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
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
278
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 13: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0x044
Type W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
OEIC
RO
0
RO
0
RO
0
RO
0
W1C
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
BEIC
PEIC
FEIC
RTIC
TXIC
RXIC
W1C
0
W1C
0
W1C
0
W1C
0
W1C
0
W1C
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
reserved
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10
OEIC
W1C
0
Overrun Error Interrupt Clear
The OEIC values are defined as follows:
Value Description
9
BEIC
W1C
0
0
No effect on the interrupt.
1
Clears interrupt.
Break Error Interrupt Clear
The BEIC values are defined as follows:
Value Description
8
PEIC
W1C
0
0
No effect on the interrupt.
1
Clears interrupt.
Parity Error Interrupt Clear
The PEIC values are defined as follows:
Value Description
0
No effect on the interrupt.
1
Clears interrupt.
October 09, 2007
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Universal Asynchronous Receivers/Transmitters (UARTs)
Bit/Field
Name
Type
Reset
7
FEIC
W1C
0
Description
Framing Error Interrupt Clear
The FEIC values are defined as follows:
Value Description
6
RTIC
W1C
0
0
No effect on the interrupt.
1
Clears interrupt.
Receive Time-Out Interrupt Clear
The RTIC values are defined as follows:
Value Description
5
TXIC
W1C
0
0
No effect on the interrupt.
1
Clears interrupt.
Transmit Interrupt Clear
The TXIC values are defined as follows:
Value Description
4
RXIC
W1C
0
0
No effect on the interrupt.
1
Clears interrupt.
Receive Interrupt Clear
The RXIC values are defined as follows:
Value Description
3:0
reserved
RO
0x00
0
No effect on the interrupt.
1
Clears interrupt.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
280
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 14: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFD0
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID4
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID4
RO
0x0000
UART Peripheral ID Register[7:0]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
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Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 15: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFD4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID5
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID5
RO
0x0000
UART Peripheral ID Register[15:8]
Can be used by software to identify the presence of this peripheral.
282
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 16: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFD8
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID6
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID6
RO
0x0000
UART Peripheral ID Register[23:16]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
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Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 17: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFDC
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID7
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0
7:0
PID7
RO
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
UART Peripheral ID Register[31:24]
Can be used by software to identify the presence of this peripheral.
284
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 18: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFE0
Type RO, reset 0x0000.0011
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
PID0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID0
RO
0x11
UART Peripheral ID Register[7:0]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
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Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 19: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFE4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID1
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID1
RO
0x00
UART Peripheral ID Register[15:8]
Can be used by software to identify the presence of this peripheral.
286
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 20: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFE8
Type RO, reset 0x0000.0018
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID2
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID2
RO
0x18
UART Peripheral ID Register[23:16]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
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Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 21: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFEC
Type RO, reset 0x0000.0001
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
PID3
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID3
RO
0x01
UART Peripheral ID Register[31:24]
Can be used by software to identify the presence of this peripheral.
288
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 22: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFF0
Type RO, reset 0x0000.000D
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID0
RO
0x0D
UART PrimeCell ID Register[7:0]
Provides software a standard cross-peripheral identification system.
October 09, 2007
289
Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 23: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFF4
Type RO, reset 0x0000.00F0
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
1
RO
1
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
CID1
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID1
RO
0xF0
UART PrimeCell ID Register[15:8]
Provides software a standard cross-peripheral identification system.
290
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 24: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFF8
Type RO, reset 0x0000.0005
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID2
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID2
RO
0x05
UART PrimeCell ID Register[23:16]
Provides software a standard cross-peripheral identification system.
October 09, 2007
291
Preliminary
Universal Asynchronous Receivers/Transmitters (UARTs)
Register 25: 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)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
Offset 0xFFC
Type RO, reset 0x0000.00B1
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
1
RO
0
RO
1
RO
1
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID3
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID3
RO
0xB1
UART PrimeCell ID Register[31:24]
Provides software a standard cross-peripheral identification system.
292
October 09, 2007
Preliminary
LM3S1911 Microcontroller
13
Synchronous Serial Interface (SSI)
®
The Stellaris microcontroller includes two Synchronous Serial Interface (SSI) modules. Each 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.
®
Each Stellaris SSI module 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
SSIRIS
SSIICR
SSICR0
SSICR1
TxFIFO
8 x 16
.
.
.
SSITx
SSISR
SSIDR
RxFIFO
8 x 16
SSIRx
Transmit/
Receive
Logic
SSIClk
SSIFss
System Clock
Clock
Prescaler
Identification Registers
13.2
SSIPCellID0
SSIPeriphID0
SSIPeriphID4
SSIPCellID1
SSIPeriphID1
SSIPeriphID5
SSIPCellID2
SSIPeriphID2
SSIPeriphID6
SSIPCellID3
SSIPeriphID3
SSIPeriphID7
.
.
.
SSICPSR
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
October 09, 2007
293
Preliminary
Synchronous Serial Interface (SSI)
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 50-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 312). 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 305).
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 25 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 “Synchronous Serial Interface (SSI)” on page 399 to view SSI timing parameters.
13.2.2
FIFO Operation
13.2.2.1 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 309), 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
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
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of the four individual maskable interrupts by setting the appropriate bits in the SSI Interrupt Mask
(SSIIM) register (see page 313). 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 315 and page 316, 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 on page 295 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
LSB
4 to 16 bits
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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 on page 296 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
LSB
4 to 16 bits
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 on page 297 and Figure 13-5 on page 297.
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Figure 13-4. Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0
SSIClk
SSIFss
SSIRx
MSB
LSB
Q
4 to 16 bits
MSB
SSITx
Note:
LSB
Q is undefined.
Figure 13-5. Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0
SSIClk
SSIFss
SSIRx LSB
MSB
LSB
MSB
4 to 16 bits
SSITx 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.
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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 on page 298, which covers both single and continuous transfers.
Figure 13-6. Freescale SPI Frame Format with SPO=0 and SPH=1
SSIClk
SSIFss
SSIRx
Q
LSB
MSB
Q
4 to 16 bits
SSITx
Note:
MSB
LSB
Q is undefined.
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 on page 299 and Figure 13-8 on page 299.
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Figure 13-7. Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0
SSIClk
SSIFss
SSIRx
MSB
LSB
Q
4 to 16 bits
SSITx
MSB
Note:
Q is undefined.
LSB
Figure 13-8. Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0
SSIClk
SSIFss
SSITx/SSIRxLSB
MSB
LSB
MSB
4 to 16 bits
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.
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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 on page 300, which covers both single and continuous transfers.
Figure 13-9. Freescale SPI Frame Format with SPO=1 and SPH=1
SSIClk
SSIFss
SSIRx
Q
LSB
MSB
Q
4 to 16 bits
SSITx
MSB
Note:
Q is undefined.
LSB
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 on page 301 shows the MICROWIRE frame format, again for a single frame. Figure
13-11 on page 302 shows the same format when back-to-back frames are transmitted.
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Figure 13-10. MICROWIRE Frame Format (Single Frame)
SSIClk
SSIFss
SSITx
MSB
LSB
8-bit control
SSIRx
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
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.
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Figure 13-11. MICROWIRE Frame Format (Continuous Transfer)
SSIClk
SSIFss
SSITx
LSB
MSB
LSB
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 on page 302 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.
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 0x0000.0000.
b. For slave mode (output enabled), set the SSICR1 register to 0x0000.0004.
c. For slave mode (output disabled), set the SSICR1 register to 0x0000.000C.
3. Configure the clock prescale divisor by writing the SSICPSR register.
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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 0x0000.0000.
3. Write the SSICPSR register with a value of 0x0000.0002.
4. Write the SSICR0 register with a value of 0x0000.09C7.
5. The SSI is then enabled by setting the SSE bit in the SSICR1 register to 1.
13.4
Register Map
Table 13-1 on page 304 lists the SSI registers. The offset listed is a hexadecimal increment to the
register’s address, relative to that SSI module’s base address:
■ SSI0: 0x4000.8000
■ SSI1: 0x4000.9000
Note:
The SSI must be disabled (see the SSE bit in the SSICR1 register) before any of the control
registers are reprogrammed.
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Table 13-1. SSI Register Map
Offset
Name
Type
Reset
Description
See
page
0x000
SSICR0
R/W
0x0000.0000
SSI Control 0
305
0x004
SSICR1
R/W
0x0000.0000
SSI Control 1
307
0x008
SSIDR
R/W
0x0000.0000
SSI Data
309
0x00C
SSISR
RO
0x0000.0003
SSI Status
310
0x010
SSICPSR
R/W
0x0000.0000
SSI Clock Prescale
312
0x014
SSIIM
R/W
0x0000.0000
SSI Interrupt Mask
313
0x018
SSIRIS
RO
0x0000.0008
SSI Raw Interrupt Status
315
0x01C
SSIMIS
RO
0x0000.0000
SSI Masked Interrupt Status
316
0x020
SSIICR
W1C
0x0000.0000
SSI Interrupt Clear
317
0xFD0
SSIPeriphID4
RO
0x0000.0000
SSI Peripheral Identification 4
318
0xFD4
SSIPeriphID5
RO
0x0000.0000
SSI Peripheral Identification 5
319
0xFD8
SSIPeriphID6
RO
0x0000.0000
SSI Peripheral Identification 6
320
0xFDC
SSIPeriphID7
RO
0x0000.0000
SSI Peripheral Identification 7
321
0xFE0
SSIPeriphID0
RO
0x0000.0022
SSI Peripheral Identification 0
322
0xFE4
SSIPeriphID1
RO
0x0000.0000
SSI Peripheral Identification 1
323
0xFE8
SSIPeriphID2
RO
0x0000.0018
SSI Peripheral Identification 2
324
0xFEC
SSIPeriphID3
RO
0x0000.0001
SSI Peripheral Identification 3
325
0xFF0
SSIPCellID0
RO
0x0000.000D
SSI PrimeCell Identification 0
326
0xFF4
SSIPCellID1
RO
0x0000.00F0
SSI PrimeCell Identification 1
327
0xFF8
SSIPCellID2
RO
0x0000.0005
SSI PrimeCell Identification 2
328
0xFFC
SSIPCellID3
RO
0x0000.00B1
SSI PrimeCell Identification 3
329
13.5
Register Descriptions
The remainder of this section lists and describes the SSI registers, in numerical order by address
offset.
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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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
SPH
SPO
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
SCR
Type
Reset
FRF
R/W
0
DSS
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15:8
SCR
R/W
0x0000
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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Bit/Field
Name
Type
Reset
5:4
FRF
R/W
0x0
Description
SSI Frame Format Select
The FRF values are defined as follows:
Value Frame Format
0x0 Freescale SPI Frame Format
0x1 Texas Intruments Synchronous Serial Frame Format
0x2 MICROWIRE Frame Format
0x3 Reserved
3:0
DSS
R/W
0x00
SSI Data Size Select
The DSS values are defined as follows:
Value
Data Size
0x0-0x2 Reserved
0x3
4-bit data
0x4
5-bit data
0x5
6-bit data
0x6
7-bit data
0x7
8-bit data
0x8
9-bit data
0x9
10-bit data
0xA
11-bit data
0xB
12-bit data
0xC
13-bit data
0xD
14-bit data
0xE
15-bit data
0xF
16-bit data
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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 (SSICR1)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x004
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
SOD
MS
SSE
LBM
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:4
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
SOD
R/W
0
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.
The SOD values are defined as follows:
Value Description
2
MS
R/W
0
0
SSI can drive SSITx output in Slave Output mode.
1
SSI must not drive the SSITx output in Slave mode.
SSI Master/Slave Select
This bit selects Master or Slave mode and can be modified only when
SSI is disabled (SSE=0).
The MS values are defined as follows:
Value Description
0
Device configured as a master.
1
Device configured as a slave.
October 09, 2007
307
Preliminary
Synchronous Serial Interface (SSI)
Bit/Field
Name
Type
Reset
1
SSE
R/W
0
Description
SSI Synchronous Serial Port Enable
Setting this bit enables SSI operation.
The SSE values are defined as follows:
Value Description
0
SSI operation disabled.
1
SSI operation enabled.
Note:
0
LBM
R/W
0
This bit must be set to 0 before any control registers
are reprogrammed.
SSI Loopback Mode
Setting this bit enables Loopback Test mode.
The LBM values are defined as follows:
Value Description
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.
308
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
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
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
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
Bit/Field
Name
Type
Reset
Description
31:16
reserved
RO
0x0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
15:0
DATA
R/W
0x0000
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.
October 09, 2007
309
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x00C
Type RO, reset 0x0000.0003
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
BSY
RFF
RNE
TNF
TFE
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
R0
1
reserved
Type
Reset
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
Description
31:5
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
4
BSY
RO
0
SSI Busy Bit
The BSY values are defined as follows:
Value Description
3
RFF
RO
0
0
SSI is idle.
1
SSI is currently transmitting and/or receiving a frame, or the
transmit FIFO is not empty.
SSI Receive FIFO Full
The RFF values are defined as follows:
Value Description
2
RNE
RO
0
0
Receive FIFO is not full.
1
Receive FIFO is full.
SSI Receive FIFO Not Empty
The RNE values are defined as follows:
Value Description
0
Receive FIFO is empty.
1
Receive FIFO is not empty.
310
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Bit/Field
Name
Type
Reset
1
TNF
RO
1
Description
SSI Transmit FIFO Not Full
The TNF values are defined as follows:
Value Description
0
TFE
R0
1
0
Transmit FIFO is full.
1
Transmit FIFO is not full.
SSI Transmit FIFO Empty
The TFE values are defined as follows:
Value Description
0
Transmit FIFO is not empty.
1
Transmit FIFO is empty.
October 09, 2007
311
Preliminary
Synchronous Serial Interface (SSI)
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x010
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CPSDVSR
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CPSDVSR
R/W
0x00
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.
312
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x014
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
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
15
14
13
12
11
10
9
8
7
6
5
4
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
3
2
1
0
TXIM
RXIM
RTIM
RORIM
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:4
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
TXIM
R/W
0
SSI Transmit FIFO Interrupt Mask
The TXIM values are defined as follows:
Value Description
2
RXIM
R/W
0
0
TX FIFO half-full or less condition interrupt is masked.
1
TX FIFO half-full or less condition interrupt is not masked.
SSI Receive FIFO Interrupt Mask
The TFE values are defined as follows:
Value Description
1
RTIM
R/W
0
0
RX FIFO half-full or more condition interrupt is masked.
1
RX FIFO half-full or more condition interrupt is not masked.
SSI Receive Time-Out Interrupt Mask
The RTIM values are defined as follows:
Value Description
0
RX FIFO time-out interrupt is masked.
1
RX FIFO time-out interrupt is not masked.
October 09, 2007
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Preliminary
Synchronous Serial Interface (SSI)
Bit/Field
Name
Type
Reset
0
RORIM
R/W
0
Description
SSI Receive Overrun Interrupt Mask
The RORIM values are defined as follows:
Value Description
0
RX FIFO overrun interrupt is masked.
1
RX FIFO overrun interrupt is not masked.
314
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x018
Type RO, reset 0x0000.0008
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
TXRIS
RXRIS
RTRIS
RORRIS
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:4
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
TXRIS
RO
1
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.
October 09, 2007
315
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x01C
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
TXMIS
RXMIS
RTMIS
RORMIS
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:4
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
TXMIS
RO
0
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.
316
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x020
Type W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RTIC
RORIC
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
W1C
0
W1C
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
RTIC
W1C
0
SSI Receive Time-Out Interrupt Clear
The RTIC values are defined as follows:
Value Description
0
RORIC
W1C
0
0
No effect on interrupt.
1
Clears interrupt.
SSI Receive Overrun Interrupt Clear
The RORIC values are defined as follows:
Value Description
0
No effect on interrupt.
1
Clears interrupt.
October 09, 2007
317
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFD0
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID4
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID4
RO
0x00
SSI Peripheral ID Register[7:0]
Can be used by software to identify the presence of this peripheral.
318
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFD4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID5
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID5
RO
0x00
SSI Peripheral ID Register[15:8]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
319
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFD8
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID6
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID6
RO
0x00
SSI Peripheral ID Register[23:16]
Can be used by software to identify the presence of this peripheral.
320
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFDC
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID7
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID7
RO
0x00
SSI Peripheral ID Register[31:24]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
321
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFE0
Type RO, reset 0x0000.0022
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
RO
0
RO
1
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0
7:0
PID0
RO
0x22
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
SSI Peripheral ID Register[7:0]
Can be used by software to identify the presence of this peripheral.
322
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFE4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID1
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID1
RO
0x00
SSI Peripheral ID Register [15:8]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
323
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFE8
Type RO, reset 0x0000.0018
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID2
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID2
RO
0x18
SSI Peripheral ID Register [23:16]
Can be used by software to identify the presence of this peripheral.
324
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFEC
Type RO, reset 0x0000.0001
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
PID3
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
PID3
RO
0x01
SSI Peripheral ID Register [31:24]
Can be used by software to identify the presence of this peripheral.
October 09, 2007
325
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFF0
Type RO, reset 0x0000.000D
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID0
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID0
RO
0x0D
SSI PrimeCell ID Register [7:0]
Provides software a standard cross-peripheral identification system.
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October 09, 2007
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LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFF4
Type RO, reset 0x0000.00F0
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
1
RO
1
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
CID1
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID1
RO
0xF0
SSI PrimeCell ID Register [15:8]
Provides software a standard cross-peripheral identification system.
October 09, 2007
327
Preliminary
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFF8
Type RO, reset 0x0000.0005
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID2
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID2
RO
0x05
SSI PrimeCell ID Register [23:16]
Provides software a standard cross-peripheral identification system.
328
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0xFFC
Type RO, reset 0x0000.00B1
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
1
RO
0
RO
1
RO
1
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
reserved
Type
Reset
CID3
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID3
RO
0xB1
SSI PrimeCell ID Register [31:24]
Provides software a standard cross-peripheral identification system.
October 09, 2007
329
Preliminary
Inter-Integrated Circuit (I2C) Interface
14
Inter-Integrated Circuit (I2C) Interface
The Inter-Integrated Circuit (I2C) bus provides bi-directional data transfer through a two-wire design
(a serial data line SDA and a serial clock line SCL), and interfaces to external I2C devices such as
serial memory (RAMs and ROMs), networking devices, LCDs, tone generators, and so on. The I2C
bus may also be used for system testing and diagnostic purposes in product development and
manufacture. The LM3S1911 microcontroller includes two I2C modules, providing the ability to
interact (both send and receive) with other I2C devices on the bus.
®
Devices on the I2C bus can be designated as either a master or a slave. Each Stellaris I2C module
supports both sending and receiving data as either a master or a slave, and also supports the
simultaneous operation as both a master and a slave. There are a total of four I2C modes: Master
®
Transmit, Master Receive, Slave Transmit, and Slave Receive. The Stellaris I2C modules can
operate at two speeds: Standard (100 Kbps) and Fast (400 Kbps).
Both the I2C master and slave can generate interrupts; the I2C master generates interrupts when
a transmit or receive operation completes (or aborts due to an error) and the I2C slave generates
interrupts when data has been sent or requested by a master.
14.1
Block Diagram
Figure 14-1. I2C Block Diagram
I2CSCL
I2C Control
Interrupt
I2CMSA
I2CSOAR
I2CMCS
I2CSCSR
I2CMDR
I2CSDR
I2CMTPR
I2CSIM
I2CMIMR
I2CSRIS
I2CMRIS
I2CSMIS
I2CMMIS
I2CSICR
2
I C Master Core
I2CSCL
2
I C I/O Select
I2CSDA
I2CSCL
I2C Slave Core
I2CMICR
I2CSDA
I2CMCR
14.2
I2CSDA
Functional Description
Each I2C module is comprised of both master and slave functions which are implemented as separate
peripherals. For proper operation, the SDA and SCL pins must be connected to bi-directional
open-drain pads. A typical I2C bus configuration is shown in Figure 14-2 on page 331.
See “I2C” on page 397 for I2C timing diagrams.
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October 09, 2007
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LM3S1911 Microcontroller
Figure 14-2. I2C Bus Configuration
RPUP
SCL
SDA
I2C Bus
I2CSCL
I2CSDA
StellarisTM
14.2.1
RPUP
SCL
SDA
3rd Party Device
with I2C Interface
SCL
SDA
3rd Party Device
with I2C Interface
I2C Bus Functional Overview
®
The I2C bus uses only two signals: SDA and SCL, named I2CSDA and I2CSCL on Stellaris
microcontrollers. SDA is the bi-directional serial data line and SCL is the bi-directional serial clock
line. The bus is considered idle when both lines are high.
Every transaction on the I2C bus is nine bits long, consisting of eight data bits and a single
acknowledge bit. The number of bytes per transfer (defined as the time between a valid START
and STOP condition, described in “START and STOP Conditions” on page 331) is unrestricted, but
each byte has to be followed by an acknowledge bit, and data must be transferred MSB first. When
a receiver cannot receive another complete byte, it can hold the clock line SCL Low and force the
transmitter into a wait state. The data transfer continues when the receiver releases the clock SCL.
14.2.1.1 START and STOP Conditions
The protocol of the I2C bus defines two states to begin and end a transaction: START and STOP.
A high-to-low transition on the SDA line while the SCL is high is defined as a START condition, and
a low-to-high transition on the SDA line while SCL is high is defined as a STOP condition. The bus
is considered busy after a START condition and free after a STOP condition. See Figure
14-3 on page 331.
Figure 14-3. START and STOP Conditions
SDA
SDA
SCL
SCL
START
condition
STOP
condition
14.2.1.2 Data Format with 7-Bit Address
Data transfers follow the format shown in Figure 14-4 on page 332. After the START condition, a
slave address is sent. This address is 7-bits long followed by an eighth bit, which is a data direction
bit (R/S bit in the I2CMSA register). A zero indicates a transmit operation (send), and a one indicates
a request for data (receive). A data transfer is always terminated by a STOP condition generated
by the master, however, a master can initiate communications with another device on the bus by
generating a repeated START condition and addressing another slave without first generating a
STOP condition. Various combinations of receive/send formats are then possible within a single
transfer.
October 09, 2007
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Preliminary
Inter-Integrated Circuit (I2C) Interface
Figure 14-4. Complete Data Transfer with a 7-Bit Address
SDA
MSB
SCL
1
2
LSB
R/S
ACK
7
8
9
Slave address
MSB
1
2
7
LSB
ACK
8
9
Data
The first seven bits of the first byte make up the slave address (see Figure 14-5 on page 332). The
eighth bit determines the direction of the message. A zero in the R/S position of the first byte means
that the master will write (send) data to the selected slave, and a one in this position means that
the master will receive data from the slave.
Figure 14-5. R/S Bit in First Byte
MSB
LSB
R/S
Slave address
14.2.1.3 Data Validity
The data on the SDA line must be stable during the high period of the clock, and the data line can
only change when SCL is low (see Figure 14-6 on page 332).
Figure 14-6. Data Validity During Bit Transfer on the I2C Bus
SDA
SCL
Data line Change
stable
of data
allowed
14.2.1.4 Acknowledge
All bus transactions have a required acknowledge clock cycle that is generated by the master. During
the acknowledge cycle, the transmitter (which can be the master or slave) releases the SDA line.
To acknowledge the transaction, the receiver must pull down SDA during the acknowledge clock
cycle. The data sent out by the receiver during the acknowledge cycle must comply with the data
validity requirements described in “Data Validity” on page 332.
When a slave receiver does not acknowledge the slave address, SDA must be left high by the slave
so that the master can generate a STOP condition and abort the current transfer. If the master
device is acting as a receiver during a transfer, it is responsible for acknowledging each transfer
made by the slave. Since the master controls the number of bytes in the transfer, it signals the end
of data to the slave transmitter by not generating an acknowledge on the last data byte. The slave
transmitter must then release SDA to allow the master to generate the STOP or a repeated START
condition.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
14.2.1.5 Arbitration
A master may start a transfer only if the bus is idle. It's possible for two or more masters to generate
a START condition within minimum hold time of the START condition. In these situations, an
arbitration scheme takes place on the SDA line, while SCL is high. During arbitration, the first of the
competing master devices to place a '1' (high) on SDA while another master transmits a '0' (low)
will switch off its data output stage and retire until the bus is idle again.
Arbitration can take place over several bits. Its first stage is a comparison of address bits, and if
both masters are trying to address the same device, arbitration continues on to the comparison of
data bits.
14.2.2
Available Speed Modes
The I2C clock rate is determined by the parameters: CLK_PRD, TIMER_PRD, SCL_LP, and SCL_HP.
where:
CLK_PRD is the system clock period
SCL_LP is the low phase of SCL (fixed at 6)
SCL_HP is the high phase of SCL (fixed at 4)
TIMER_PRD is the programmed value in the I2C Master Timer Period (I2CMTPR) register (see
page 350).
The I2C clock period is calculated as follows:
SCL_PERIOD = 2*(1 + TIMER_PRD)*(SCL_LP + SCL_HP)*CLK_PRD
For example:
CLK_PRD = 50 ns
TIMER_PRD = 2
SCL_LP=6
SCL_HP=4
yields a SCL frequency of:
1/T = 333 Khz
Table 14-1 on page 333 gives examples of timer period, system clock, and speed mode (Standard
or Fast).
Table 14-1. Examples of I2C Master Timer Period versus Speed Mode
System Clock Timer Period Standard Mode Timer Period Fast Mode
4 Mhz
0x01
100 Kbps
-
-
6 Mhz
0x02
100 Kbps
-
-
12.5 Mhz
0x06
89 Kbps
0x01
312 Kbps
16.7 Mhz
0x08
93 Kbps
0x02
278 Kbps
20 Mhz
0x09
100 Kbps
0x02
333 Kbps
25 Mhz
0x0C
96.2 Kbps
0x03
312 Kbps
33Mhz
0x10
97.1 Kbps
0x04
330 Kbps
40Mhz
0x13
100 Kbps
0x04
400 Kbps
October 09, 2007
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Preliminary
Inter-Integrated Circuit (I2C) Interface
System Clock Timer Period Standard Mode Timer Period Fast Mode
50Mhz
14.2.3
0x18
100 Kbps
0x06
357 Kbps
Interrupts
The I2C can generate interrupts when the following conditions are observed:
■ Master transaction completed
■ Master transaction error
■ Slave transaction received
■ Slave transaction requested
There is a separate interrupt signal for the I2C master and I2C modules. While both modules can
generate interrupts for multiple conditions, only a single interrupt signal is sent to the interrupt
controller.
14.2.3.1 I2C Master Interrupts
The I2C master module generates an interrupt when a transaction completes (either transmit or
receive), or when an error occurs during a transaction. To enable the I2C master interrupt, software
must write a '1' to the I2C Master Interrupt Mask (I2CMIMR) register. When an interrupt condition
is met, software must check the ERROR bit in the I2C Master Control/Status (I2CMCS) register to
verify that an error didn't occur during the last transaction. An error condition is asserted if the last
transaction wasn't acknowledge by the slave or if the master was forced to give up ownership of
the bus due to a lost arbitration round with another master. If an error is not detected, the application
can proceed with the transfer. The interrupt is cleared by writing a '1' to the I2C Master Interrupt
Clear (I2CMICR) register.
If the application doesn't require the use of interrupts, the raw interrupt status is always visible via
the I2C Master Raw Interrupt Status (I2CMRIS) register.
14.2.3.2 I2C Slave Interrupts
The slave module generates interrupts as it receives requests from an I2C master. To enable the
I2C slave interrupt, write a '1' to the I2C Slave Interrupt Mask (I2CSIMR) register. Software
determines whether the module should write (transmit) or read (receive) data from the I2C Slave
Data (I2CSDR) register, by checking the RREQ and TREQ bits of the I2C Slave Control/Status
(I2CSCSR) register. If the slave module is in receive mode and the first byte of a transfer is received,
the FBR bit is set along with the RREQ bit. The interrupt is cleared by writing a '1' to the I2C Slave
Interrupt Clear (I2CSICR) register.
If the application doesn't require the use of interrupts, the raw interrupt status is always visible via
the I2C Slave Raw Interrupt Status (I2CSRIS) register.
14.2.4
Loopback Operation
The I2C modules can be placed into an internal loopback mode for diagnostic or debug work. This
is accomplished by setting the LPBK bit in the I2C Master Configuration (I2CMCR) register. In
loopback mode, the SDA and SCL signals from the master and slave modules are tied together.
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14.2.5
Command Sequence Flow Charts
This section details the steps required to perform the various I2C transfer types in both master and
slave mode.
14.2.5.1 I2C Master Command Sequences
The figures that follow show the command sequences available for the I2C master.
Figure 14-7. Master Single SEND
Idle
Write Slave
Address to
I2CMSA
Sequence
may be
omitted in a
Single Master
system
Write data to
I2CMDR
Read I2CMCS
NO
BUSBSY bit=0?
YES
Write ---0-111 to
I2CMCS
Read I2CMCS
NO
BUSY bit=0?
YES
Error Service
NO
ERROR bit=0?
YES
Idle
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Figure 14-8. Master Single RECEIVE
Idle
Write Slave
Address to
I2CMSA
Sequence may be
omitted in a Single
Master system
Read I2CMCS
NO
BUSBSY bit=0?
YES
Write ---00111 to
I2CMCS
Read I2CMCS
NO
BUSY bit=0?
YES
Error Service
NO
ERROR bit=0?
YES
Read data from
I2CMDR
Idle
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Figure 14-9. Master Burst SEND
Idle
Write Slave
Address to
I2CMSA
Sequence
may be
omitted in a
Single Master
system
Read I2CMCS
Write data to
I2CMDR
BUSY bit=0?
YES
Read I2CMCS
ERROR bit=0?
NO
NO
NO
BUSBSY bit=0?
YES
Write data to
I2CMDR
YES
Write ---0-011 to
I2CMCS
NO
ARBLST bit=1?
YES
Write ---0-001 to
I2CMCS
NO
Index=n?
YES
Write ---0-101 to
I2CMCS
Write ---0-100 to
I2CMCS
Error Service
Idle
Read I2CMCS
NO
BUSY bit=0?
YES
Error Service
NO
ERROR bit=0?
YES
Idle
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Figure 14-10. Master Burst RECEIVE
Idle
Write Slave
Address to
I2CMSA
Sequence
may be
omitted in a
Single Master
system
Read I2CMCS
BUSY bit=0?
Read I2CMCS
NO
YES
NO
BUSBSY bit=0?
ERROR bit=0?
NO
YES
Write ---01011 to
I2CMCS
NO
Read data from
I2CMDR
ARBLST bit=1?
YES
Write ---01001 to
I2CMCS
NO
Write ---0-100 to
I2CMCS
Index=m-1?
Error Service
YES
Write ---00101 to
I2CMCS
Idle
Read I2CMCS
BUSY bit=0?
NO
YES
NO
ERROR bit=0?
YES
Error Service
Read data from
I2CMDR
Idle
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Figure 14-11. Master Burst RECEIVE after Burst SEND
Idle
Master operates in
Master Transmit mode
STOP condition is not
generated
Write Slave
Address to
I2CMSA
Write ---01011 to
I2CMCS
Repeated START
condition is generated
with changing data
direction
Master operates in
Master Receive mode
Idle
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Figure 14-12. Master Burst SEND after Burst RECEIVE
Idle
Master operates in
Master Receive mode
STOP condition is not
generated
Write Slave
Address to
I2CMSA
Write ---0-011 to
I2CMCS
Repeated START
condition is generated
with changing data
direction
Master operates in
Master Transmit mode
Idle
14.2.5.2 I2C Slave Command Sequences
Figure 14-13 on page 341 presents the command sequence available for the I2C slave.
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Figure 14-13. Slave Command Sequence
Idle
Write OWN Slave
Address to
I2CSOAR
Write -------1 to
I2CSCSR
Read I2CSCSR
NO
TREQ bit=1?
YES
Write data to
I2CSDR
14.3
NO
RREQ bit=1?
FBR is
also valid
YES
Read data from
I2CSDR
Initialization and Configuration
The following example shows how to configure the I2C module to send a single byte as a master.
This assumes the system clock is 20 MHz.
1. Enable the I2C clock by writing a value of 0x0000.1000 to the RCGC1 register in the System
Control module.
2. Enable the clock to the appropriate GPIO module via the RCGC2 register in the System Control
module.
3. In the GPIO module, enable the appropriate pins for their alternate function using the
GPIOAFSEL register. Also, be sure to enable the same pins for Open Drain operation.
4. Initialize the I2C Master by writing the I2CMCR register with a value of 0x0000.0020.
5. Set the desired SCL clock speed of 100 Kbps by writing the I2CMTPR register with the correct
value. The value written to the I2CMTPR register represents the number of system clock periods
in one SCL clock period. The TPR value is determined by the following equation:
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TPR = (System Clock / (2 * (SCL_LP + SCL_HP) * SCL_CLK)) - 1;
TPR = (20MHz / (2 * (6 + 4) * 100000)) - 1;
TPR = 9
Write the I2CMTPR register with the value of 0x0000.0009.
6. Specify the slave address of the master and that the next operation will be a Send by writing
the I2CMSA register with a value of 0x0000.0076. This sets the slave address to 0x3B.
7. Place data (byte) to be sent in the data register by writing the I2CMDR register with the desired
data.
8. Initiate a single byte send of the data from Master to Slave by writing the I2CMCS register with
a value of 0x0000.0007 (STOP, START, RUN).
9. Wait until the transmission completes by polling the I2CMCS register’s BUSBSY bit until it has
been cleared.
14.4
I2C Register Map
Table 14-2 on page 342 lists the I2C registers. All addresses given are relative to the I2C base
addresses for the master and slave:
■ I2C Master 0: 0x4002.0000
■ I2C Slave 0: 0x4002.0800
■ I2C Master 1: 0x4002.1000
■ I2C Slave 1: 0x4002.1800
Table 14-2. Inter-Integrated Circuit (I2C) Interface Register Map
Offset
Description
See
page
Name
Type
Reset
0x000
I2CMSA
R/W
0x0000.0000
I2C Master Slave Address
344
0x004
I2CMCS
R/W
0x0000.0000
I2C Master Control/Status
345
0x008
I2CMDR
R/W
0x0000.0000
I2C Master Data
349
0x00C
I2CMTPR
R/W
0x0000.0001
I2C Master Timer Period
350
0x010
I2CMIMR
R/W
0x0000.0000
I2C Master Interrupt Mask
351
0x014
I2CMRIS
RO
0x0000.0000
I2C Master Raw Interrupt Status
352
0x018
I2CMMIS
RO
0x0000.0000
I2C Master Masked Interrupt Status
353
0x01C
I2CMICR
WO
0x0000.0000
I2C Master Interrupt Clear
354
0x020
I2CMCR
R/W
0x0000.0000
I2C Master Configuration
355
I2CSOAR
R/W
0x0000.0000
I2C Slave Own Address
357
I2C Master
I2C
Slave
0x000
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Offset
Name
0x004
Reset
I2CSCSR
RO
0x0000.0000
I2C Slave Control/Status
358
0x008
I2CSDR
R/W
0x0000.0000
I2C Slave Data
360
0x00C
I2CSIMR
R/W
0x0000.0000
I2C Slave Interrupt Mask
361
0x010
I2CSRIS
RO
0x0000.0000
I2C Slave Raw Interrupt Status
362
0x014
I2CSMIS
RO
0x0000.0000
I2C Slave Masked Interrupt Status
363
0x018
I2CSICR
WO
0x0000.0000
I2C Slave Interrupt Clear
364
14.5
Description
See
page
Type
Register Descriptions (I2C Master)
The remainder of this section lists and describes the I2C master registers, in numerical order by
address offset. See also “Register Descriptions (I2C Slave)” on page 356.
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Register 1: I2C Master Slave Address (I2CMSA), offset 0x000
This register consists of eight bits: seven address bits (A6-A0), and a Receive/Send bit, which
determines if the next operation is a Receive (High), or Send (Low).
I2C Master Slave Address (I2CMSA)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
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
reserved
Type
Reset
reserved
Type
Reset
SA
RO
0
R/S
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:1
SA
R/W
0
I2C Slave Address
This field specifies bits A6 through A0 of the slave address.
0
R/S
R/W
0
Receive/Send
The R/S bit specifies if the next operation is a Receive (High) or Send
(Low).
0: Send
1: Receive
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Register 2: I2C Master Control/Status (I2CMCS), offset 0x004
This register accesses four control bits when written, and accesses seven status bits when read.
The status register consists of seven bits, which when read determine the state of the I2C bus
controller.
The control register consists of four bits: the RUN, START, STOP, and ACK bits. The START bit causes
the generation of the START, or REPEATED START condition.
The STOP bit determines if the cycle stops at the end of the data cycle, or continues on to a burst.
To generate a single send cycle, the I2C Master Slave Address (I2CMSA) register is written with
the desired address, the R/S bit is set to 0, and the Control register is written with ACK=X (0 or 1),
STOP=1, START=1, and RUN=1 to perform the operation and stop. When the operation is completed
(or aborted due an error), the interrupt pin becomes active and the data may be read from the
I2CMDR register. When the I2C module operates in Master receiver mode, the ACK bit must be set
normally to logic 1. This causes the I2C bus controller to send an acknowledge automatically after
each byte. This bit must be reset when the I2C bus controller requires no further data to be sent
from the slave transmitter.
Read-Only Status Register
I2C Master Control/Status (I2CMCS)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x004
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
BUSBSY
IDLE
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
ARBLST DATACK ADRACK ERROR
RO
0
RO
0
RO
0
RO
0
BUSY
RO
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6
BUSBSY
RO
0
Bus Busy
This bit specifies the state of the I2C bus. If set, the bus is busy;
otherwise, the bus is idle. The bit changes based on the START and
STOP conditions.
5
IDLE
RO
0
I2C Idle
This bit specifies the I2C controller state. If set, the controller is idle;
otherwise the controller is not idle.
4
ARBLST
RO
0
Arbitration Lost
This bit specifies the result of bus arbitration. If set, the controller lost
arbitration; otherwise, the controller won arbitration.
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Bit/Field
Name
Type
Reset
3
DATACK
RO
0
Description
Acknowledge Data
This bit specifies the result of the last data operation. If set, the
transmitted data was not acknowledged; otherwise, the data was
acknowledged.
2
ADRACK
RO
0
Acknowledge Address
This bit specifies the result of the last address operation. If set, the
transmitted address was not acknowledged; otherwise, the address was
acknowledged.
1
ERROR
RO
0
Error
This bit specifies the result of the last bus operation. If set, an error
occurred on the last operation; otherwise, no error was detected. The
error can be from the slave address not being acknowledged, the
transmit data not being acknowledged, or because the controller lost
arbitration.
0
BUSY
RO
I2C Busy
0
This bit specifies the state of the controller. If set, the controller is busy;
otherwise, the controller is idle. When the BUSY bit is set, the other status
bits are not valid.
Write-Only Control Register
I2C Master Control/Status (I2CMCS)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x004
Type WO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WO
0
WO
0
WO
0
WO
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
15
14
13
12
11
10
9
8
7
6
5
4
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
3
2
1
0
ACK
STOP
START
RUN
WO
0
WO
0
WO
0
WO
0
Bit/Field
Name
Type
Reset
Description
31:4
reserved
WO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3
ACK
WO
0
Data Acknowledge Enable
When set, causes received data byte to be acknowledged automatically
by the master. See field decoding in Table 14-3 on page 347.
2
STOP
WO
0
Generate STOP
When set, causes the generation of the STOP condition. See field
decoding in Table 14-3 on page 347.
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Bit/Field
Name
Type
Reset
1
START
WO
0
Description
Generate START
When set, causes the generation of a START or repeated START
condition. See field decoding in Table 14-3 on page 347.
0
RUN
WO
I2C Master Enable
0
When set, allows the master to send or receive data. See field decoding
in Table 14-3 on page 347.
Table 14-3. Write Field Decoding for I2CMCS[3:0] Field (Sheet 1 of 3)
Current I2CMSA[0]
State
R/S
Idle
I2CMCS[3:0]
ACK
Description
STOP
START
RUN
0
X
a
0
1
1
0
X
1
1
1
START condition followed by a SEND and STOP
condition (master remains in Idle state).
1
0
0
1
1
START condition followed by RECEIVE operation with
negative ACK (master goes to the Master Receive state).
1
0
1
1
1
START condition followed by RECEIVE and STOP
condition (master remains in Idle state).
1
1
0
1
1
START condition followed by RECEIVE (master goes to
the Master Receive state).
1
1
1
1
1
Illegal.
START condition followed by SEND (master goes to the
Master Transmit state).
All other combinations not listed are non-operations. NOP.
Master
Transmit
X
X
0
0
1
SEND operation (master remains in Master Transmit
state).
X
X
1
0
0
STOP condition (master goes to Idle state).
X
X
1
0
1
SEND followed by STOP condition (master goes to Idle
state).
0
X
0
1
1
Repeated START condition followed by a SEND (master
remains in Master Transmit state).
0
X
1
1
1
Repeated START condition followed by SEND and STOP
condition (master goes to Idle state).
1
0
0
1
1
Repeated START condition followed by a RECEIVE
operation with a negative ACK (master goes to Master
Receive state).
1
0
1
1
1
Repeated START condition followed by a SEND and
STOP condition (master goes to Idle state).
1
1
0
1
1
Repeated START condition followed by RECEIVE (master
goes to Master Receive state).
1
1
1
1
1
Illegal.
All other combinations not listed are non-operations. NOP.
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Current I2CMSA[0]
State
R/S
Master
Receive
I2CMCS[3:0]
Description
ACK
STOP
START
RUN
X
0
0
0
1
RECEIVE operation with negative ACK (master remains
in Master Receive state).
X
X
1
0
0
STOP condition (master goes to Idle state).
X
0
1
0
1
RECEIVE followed by STOP condition (master goes to
Idle state).
X
1
0
0
1
RECEIVE operation (master remains in Master Receive
state).
X
1
1
0
1
Illegal.
1
0
0
1
1
Repeated START condition followed by RECEIVE
operation with a negative ACK (master remains in Master
Receive state).
1
0
1
1
1
Repeated START condition followed by RECEIVE and
STOP condition (master goes to Idle state).
1
1
0
1
1
Repeated START condition followed by RECEIVE (master
remains in Master Receive state).
0
X
0
1
1
Repeated START condition followed by SEND (master
goes to Master Transmit state).
0
X
1
1
1
Repeated START condition followed by SEND and STOP
condition (master goes to Idle state).
b
All other combinations not listed are non-operations. NOP.
a. An X in a table cell indicates the bit can be 0 or 1.
b. In Master Receive mode, a STOP condition should be generated only after a Data Negative Acknowledge executed by
the master or an Address Negative Acknowledge executed by the slave.
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Register 3: I2C Master Data (I2CMDR), offset 0x008
This register contains the data to be transmitted when in the Master Transmit state, and the data
received when in the Master Receive state.
I2C Master Data (I2CMDR)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
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
reserved
Type
Reset
reserved
Type
Reset
DATA
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DATA
R/W
0x00
Data Transferred
Data transferred during transaction.
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Register 4: I2C Master Timer Period (I2CMTPR), offset 0x00C
This register specifies the period of the SCL clock.
I2C Master Timer Period (I2CMTPR)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x00C
Type R/W, reset 0x0000.0001
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
1
reserved
Type
Reset
reserved
Type
Reset
TPR
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
TPR
R/W
0x1
SCL Clock Period
This field specifies the period of the SCL clock.
SCL_PRD = 2*(1 + TPR)*(SCL_LP + SCL_HP)*CLK_PRD
where:
SCL_PRD is the SCL line period (I2C clock).
TPR is the Timer Period register value (range of 1 to 255).
SCL_LP is the SCL Low period (fixed at 6).
SCL_HP is the SCL High period (fixed at 4).
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Register 5: I2C Master Interrupt Mask (I2CMIMR), offset 0x010
This register controls whether a raw interrupt is promoted to a controller interrupt.
I2C Master Interrupt Mask (I2CMIMR)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x010
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
IM
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
IM
R/W
0
Interrupt Mask
This bit controls whether a raw interrupt is promoted to a controller
interrupt. If set, the interrupt is not masked and the interrupt is promoted;
otherwise, the interrupt is masked.
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Inter-Integrated Circuit (I2C) Interface
Register 6: I2C Master Raw Interrupt Status (I2CMRIS), offset 0x014
This register specifies whether an interrupt is pending.
I2C Master Raw Interrupt Status (I2CMRIS)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x014
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
RIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
RIS
RO
0
Raw Interrupt Status
This bit specifies the raw interrupt state (prior to masking) of the I2C
master block. If set, an interrupt is pending; otherwise, an interrupt is
not pending.
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LM3S1911 Microcontroller
Register 7: I2C Master Masked Interrupt Status (I2CMMIS), offset 0x018
This register specifies whether an interrupt was signaled.
I2C Master Masked Interrupt Status (I2CMMIS)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x018
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
MIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
MIS
RO
0
Masked Interrupt Status
This bit specifies the raw interrupt state (after masking) of the I2C master
block. If set, an interrupt was signaled; otherwise, an interrupt has not
been generated since the bit was last cleared.
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Inter-Integrated Circuit (I2C) Interface
Register 8: I2C Master Interrupt Clear (I2CMICR), offset 0x01C
This register clears the raw interrupt.
I2C Master Interrupt Clear (I2CMICR)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x01C
Type WO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
WO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
IC
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
IC
WO
0
Interrupt Clear
This bit controls the clearing of the raw interrupt. A write of 1 clears the
interrupt; otherwise, a write of 0 has no affect on the interrupt state. A
read of this register returns no meaningful data.
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October 09, 2007
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LM3S1911 Microcontroller
Register 9: I2C Master Configuration (I2CMCR), offset 0x020
This register configures the mode (Master or Slave) and sets the interface for test mode loopback.
I2C Master Configuration (I2CMCR)
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
Offset 0x020
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
SFE
MFE
RO
0
RO
0
RO
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
reserved
RO
0
RO
0
LPBK
RO
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:6
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5
SFE
R/W
0
I2C Slave Function Enable
This bit specifies whether the interface may operate in Slave mode. If
set, Slave mode is enabled; otherwise, Slave mode is disabled.
4
MFE
R/W
0
I2C Master Function Enable
This bit specifies whether the interface may operate in Master mode. If
set, Master mode is enabled; otherwise, Master mode is disabled and
the interface clock is disabled.
3:1
reserved
RO
0x00
0
LPBK
R/W
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
I2C Loopback
This bit specifies whether the interface is operating normally or in
Loopback mode. If set, the device is put in a test mode loopback
configuration; otherwise, the device operates normally.
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Inter-Integrated Circuit (I2C) Interface
14.6
Register Descriptions (I2C Slave)
The remainder of this section lists and describes the I2C slave registers, in numerical order by
address offset. See also “Register Descriptions (I2C Master)” on page 343.
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October 09, 2007
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LM3S1911 Microcontroller
Register 10: I2C Slave Own Address (I2CSOAR), offset 0x000
®
This register consists of seven address bits that identify the Stellaris I2C device on the I2C bus.
I2C Slave Own Address (I2CSOAR)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
OAR
R/W
0
Bit/Field
Name
Type
Reset
Description
31:7
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
6:0
OAR
R/W
0x00
I2C Slave Own Address
This field specifies bits A6 through A0 of the slave address.
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Preliminary
Inter-Integrated Circuit (I2C) Interface
Register 11: I2C Slave Control/Status (I2CSCSR), offset 0x004
This register accesses one control bit when written, and three status bits when read.
The read-only Status register consists of three bits: the FBR, RREQ, and TREQ bits. The First
®
Byte Received (FBR) bit is set only after the Stellaris device detects its own slave address
and receives the first data byte from the I2C master. The Receive Request (RREQ) bit indicates
®
that the Stellaris I2C device has received a data byte from an I2C master. Read one data byte from
the I2C Slave Data (I2CSDR) register to clear the RREQ bit. The Transmit Request (TREQ) bit
®
indicates that the Stellaris I2C device is addressed as a Slave Transmitter. Write one data byte
2
into the I C Slave Data (I2CSDR) register to clear the TREQ bit.
The write-only Control register consists of one bit: the DA bit. The DA bit enables and disables the
®
Stellaris I2C slave operation.
Read-Only Status Register
I2C Slave Control/Status (I2CSCSR)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x004
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
FBR
TREQ
RREQ
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
Description
31:3
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
2
FBR
RO
0
First Byte Received
Indicates that the first byte following the slave’s own address is received.
This bit is only valid when the RREQ bit is set, and is automatically cleared
when data has been read from the I2CSDR register.
Note:
1
TREQ
RO
0
This bit is not used for slave transmit operations.
Transmit Request
This bit specifies the state of the I2C slave with regards to outstanding
transmit requests. If set, the I2C unit has been addressed as a slave
transmitter and uses clock stretching to delay the master until data has
been written to the I2CSDR register. Otherwise, there is no outstanding
transmit request.
0
RREQ
RO
0
Receive Request
This bit specifies the status of the I2C slave with regards to outstanding
receive requests. If set, the I2C unit has outstanding receive data from
the I2C master and uses clock stretching to delay the master until the
data has been read from the I2CSDR register. Otherwise, no receive
data is outstanding.
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October 09, 2007
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LM3S1911 Microcontroller
Write-Only Control Register
I2C Slave Control/Status (I2CSCSR)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x004
Type WO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
WO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
DA
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
DA
WO
0
Device Active
1=Enables the I2C slave operation.
0=Disables the I2C slave operation.
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Preliminary
Inter-Integrated Circuit (I2C) Interface
Register 12: I2C Slave Data (I2CSDR), offset 0x008
This register contains the data to be transmitted when in the Slave Transmit state, and the data
received when in the Slave Receive state.
I2C Slave Data (I2CSDR)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
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
reserved
Type
Reset
reserved
Type
Reset
DATA
RO
0
Bit/Field
Name
Type
Reset
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
DATA
R/W
0x0
Data for Transfer
This field contains the data for transfer during a slave receive or transmit
operation.
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October 09, 2007
Preliminary
LM3S1911 Microcontroller
Register 13: I2C Slave Interrupt Mask (I2CSIMR), offset 0x00C
This register controls whether a raw interrupt is promoted to a controller interrupt.
I2C Slave Interrupt Mask (I2CSIMR)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x00C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
IM
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
IM
R/W
0
Interrupt Mask
This bit controls whether a raw interrupt is promoted to a controller
interrupt. If set, the interrupt is not masked and the interrupt is promoted;
otherwise, the interrupt is masked.
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Inter-Integrated Circuit (I2C) Interface
Register 14: I2C Slave Raw Interrupt Status (I2CSRIS), offset 0x010
This register specifies whether an interrupt is pending.
I2C Slave Raw Interrupt Status (I2CSRIS)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x010
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
RIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
RIS
RO
0
Raw Interrupt Status
This bit specifies the raw interrupt state (prior to masking) of the I2C
slave block. If set, an interrupt is pending; otherwise, an interrupt is not
pending.
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October 09, 2007
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LM3S1911 Microcontroller
Register 15: I2C Slave Masked Interrupt Status (I2CSMIS), offset 0x014
This register specifies whether an interrupt was signaled.
I2C Slave Masked Interrupt Status (I2CSMIS)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x014
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
MIS
RO
0
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
MIS
RO
0
Masked Interrupt Status
This bit specifies the raw interrupt state (after masking) of the I2C slave
block. If set, an interrupt was signaled; otherwise, an interrupt has not
been generated since the bit was last cleared.
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Inter-Integrated Circuit (I2C) Interface
Register 16: I2C Slave Interrupt Clear (I2CSICR), offset 0x018
This register clears the raw interrupt.
I2C Slave Interrupt Clear (I2CSICR)
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
Offset 0x018
Type WO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
WO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
IC
Bit/Field
Name
Type
Reset
Description
31:1
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
IC
WO
0
Clear Interrupt
This bit controls the clearing of the raw interrupt. A write of 1 clears the
interrupt; otherwise a write of 0 has no affect on the interrupt state. A
read of this register returns no meaningful data.
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15
Analog Comparators
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S1911 controller provides two independent integrated analog comparators that can be
configured to drive an output or generate an interrupt
Note:
Not all comparators have the option to drive an output pin. See the Comparator Operating
Mode tables for more information.
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 to cause it to start
capturing a sample sequence.
15.1
Block Diagram
Figure 15-1. Analog Comparator Module Block Diagram
C1-
-ve input
C1+
+ve input
Comparator 1
output
C1o
+ve input (alternate)
ACCTL1
ACSTAT1
interrupt
reference input
C0-
-ve input
C0+
+ve input
interrupt
Comparator 0
output
C0o
+ve input (alternate)
ACCTL0
ACSTAT0
interrupt
reference input
interrupt
Voltage
Ref
internal
bus
15.2
ACREFCTL
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.
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Preliminary
Analog Comparators
VIN- < VIN+, VOUT = 1
VIN- > VIN+, VOUT = 0
As shown in Figure 15-2 on page 366, 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.
Figure 15-2. Structure of Comparator Unit
-ve input
+ve input
output
0
+ve input (alternate)
1
reference input
2
CINV
IntGen
ACCTL
interrupt
internal
bus
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 the Comparator Operating Mode tables.
Typically, the comparator output is used internally to generate controller interrupts. It may also be
used to drive an external pin.
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 the
Comparator Operating Mode tables.
Table 15-1. Comparator 0 Operating Modes
ACCNTL0 Comparator 0
ASRCP
VIN- VIN+
Output Interrupt
00
C0-
C0+
C0o
yes
01
C0-
C0+
C0o
yes
10
C0-
Vref
C0o
yes
11
C0- reserved
C0o
yes
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Table 15-2. Comparator 1 Operating Modes
ACCNTL1 Comparator 1
ASRCP
VIN- VIN+
00
C1- C1o/C1+ C1o/C1+
Output
yes
01
C1-
C0+
C1o/C1+
yes
10
C1-
Vref
C1o/C1+
yes
11
C1- reserved C1o/C1+
yes
a
Interrupt
a. C1o and C1+ signals share a single pin and may only be used as one or the other.
15.2.1
Internal Reference Programming
The structure of the internal reference is shown in Figure 15-3 on page 367. This is controlled by a
single configuration register (ACREFCTL). Table 15-3 on page 367 shows the programming options
to develop specific internal reference values, to compare an external voltage against a particular
voltage generated internally.
Figure 15-3. Comparator Internal Reference Structure
8R
AVDD
8R
R
R
R
R
•••
EN
15
14
•••
1
0
Decoder
VREF
internal
reference
RNG
Table 15-3. Internal Reference Voltage and ACREFCTL Field Values
ACREFCTL Register
Output Reference Voltage Based on VREF Field Value
EN Bit Value RNG Bit Value
EN=0
RNG=X
0 V (GND) for any value of VREF; however, it is recommended that RNG=1 and VREF=0
for the least noisy ground reference.
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Preliminary
Analog Comparators
ACREFCTL Register
Output Reference Voltage Based on VREF Field Value
EN Bit Value RNG Bit Value
EN=1
RNG=0
Total resistance in ladder is 32 R.
V
V
V
RE F
= AV
RE F
R EF
= AV
DD
DD
R
-------F
× ------V----RE
R
T
( VREF + 8 )
× -----------------------------32
= 0.825 + 0.103 VR EF
The range of internal reference in this mode is 0.825-2.37 V.
RNG=1
Total resistance in ladder is 24 R.
V
V
RE F
RE F
= AV
= AV
DD
DD
R
-------F
× ------V----RE
R
T
( VREF )
× --------------------24
VREF = 0.1375 x VREF
The range of internal reference for this mode is 0.0-2.0625 V.
15.3
Initialization and Configuration
The following example shows how to configure an analog comparator to read back its output value
from an internal register.
1. Enable the analog comparator 0 clock by writing a value of 0x0010.0000 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 0x0000.030C.
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 0x0000.040C.
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.
15.4
Register Map
Table 15-4 on page 369 lists the comparator registers. The offset listed is a hexadecimal increment
to the register’s address, relative to the Analog Comparator base address of 0x4003.C000.
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Table 15-4. Analog Comparators Register Map
Name
Type
Reset
0x00
ACMIS
R/W1C
0x0000.0000
Analog Comparator Masked Interrupt Status
370
0x04
ACRIS
RO
0x0000.0000
Analog Comparator Raw Interrupt Status
371
0x08
ACINTEN
R/W
0x0000.0000
Analog Comparator Interrupt Enable
372
0x10
ACREFCTL
R/W
0x0000.0000
Analog Comparator Reference Voltage Control
373
0x20
ACSTAT0
RO
0x0000.0000
Analog Comparator Status 0
374
0x24
ACCTL0
R/W
0x0000.0000
Analog Comparator Control 0
375
0x40
ACSTAT1
RO
0x0000.0000
Analog Comparator Status 1
374
0x44
ACCTL1
R/W
0x0000.0000
Analog Comparator Control 1
375
15.5
Description
See
page
Offset
Register Descriptions
The remainder of this section lists and describes the Analog Comparator registers, in numerical
order by address offset.
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Analog Comparators
Register 1: Analog Comparator Masked Interrupt Status (ACMIS), offset 0x00
This register provides a summary of the interrupt status (masked) of the comparators.
Analog Comparator Masked Interrupt Status (ACMIS)
Base 0x4003.C000
Offset 0x00
Type R/W1C, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
IN1
IN0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W1C
0
R/W1C
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
IN1
R/W1C
0
Comparator 1 Masked Interrupt Status
Gives the masked interrupt state of this interrupt. Write 1 to this bit to
clear the pending interrupt.
0
IN0
R/W1C
0
Comparator 0 Masked Interrupt Status
Gives the masked interrupt state of this interrupt. Write 1 to this bit to
clear the pending interrupt.
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Register 2: Analog Comparator Raw Interrupt Status (ACRIS), offset 0x04
This register provides a summary of the interrupt status (raw) of the comparators.
Analog Comparator Raw Interrupt Status (ACRIS)
Base 0x4003.C000
Offset 0x04
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
IN1
IN0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
IN1
RO
0
Comparator 1 Interrupt Status
When set, indicates that an interrupt has been generated by comparator
1.
0
IN0
RO
0
Comparator 0 Interrupt Status
When set, indicates that an interrupt has been generated by comparator
0.
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Analog Comparators
Register 3: Analog Comparator Interrupt Enable (ACINTEN), offset 0x08
This register provides the interrupt enable for the comparators.
Analog Comparator Interrupt Enable (ACINTEN)
Base 0x4003.C000
Offset 0x08
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
IN1
IN0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
IN1
R/W
0
Comparator 1 Interrupt Enable
When set, enables the controller interrupt from the comparator 1 output.
0
IN0
R/W
0
Comparator 0 Interrupt Enable
When set, enables the controller interrupt from the comparator 0 output.
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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)
Base 0x4003.C000
Offset 0x10
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
1
0
R/W
0
R/W
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
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
7
6
5
4
3
2
9
8
EN
RNG
R/W
0
R/W
0
reserved
Type
Reset
RO
0
reserved
RO
0
RO
0
RO
0
VREF
RO
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:10
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
9
EN
R/W
0
Resistor Ladder Enable
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
Resistor Ladder Range
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.
7:4
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
3:0
VREF
R/W
0x00
Resistor Ladder Voltage Ref
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
15-3 on page 367 for some output reference voltage examples.
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Preliminary
Analog Comparators
Register 5: Analog Comparator Status 0 (ACSTAT0), offset 0x20
Register 6: Analog Comparator Status 1 (ACSTAT1), offset 0x40
These registers specify the current output value of the comparator.
Analog Comparator Status 0 (ACSTAT0)
Base 0x4003.C000
Offset 0x20
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
OVAL
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:2
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
OVAL
RO
0
Comparator Output Value
The OVAL bit specifies the current output value of the comparator.
0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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LM3S1911 Microcontroller
Register 7: Analog Comparator Control 0 (ACCTL0), offset 0x24
Register 8: Analog Comparator Control 1 (ACCTL1), offset 0x44
These registers configure the comparator’s input and output.
Analog Comparator Control 0 (ACCTL0)
Base 0x4003.C000
Offset 0x24
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
CINV
reserved
RO
0
RO
0
RO
0
RO
0
R/W
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
ASRCP
reserved
ISLVAL
R/W
0
ISEN
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:11
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
10:9
ASRCP
R/W
0x00
Analog Source Positive
The ASRCP field specifies the source of input voltage to the VIN+ terminal
of the comparator. The encodings for this field are as follows:
Value Function
0x0
Pin value
0x1
Pin value of C0+
0x2
Internal voltage reference
0x3
Reserved
8:5
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
4
ISLVAL
R/W
0
Interrupt Sense Level Value
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.
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Preliminary
Analog Comparators
Bit/Field
Name
Type
Reset
3:2
ISEN
R/W
0x0
Description
Interrupt Sense
The ISEN field specifies the sense of the comparator output that
generates an interrupt. The sense conditioning is as follows:
Value Function
1
CINV
R/W
0
0x0
Level sense, see ISLVAL
0x1
Falling edge
0x2
Rising edge
0x3
Either edge
Comparator Output Invert
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.
0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
376
October 09, 2007
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LM3S1911 Microcontroller
16
Pin Diagram
Figure 16-1 on page 377 shows the pin diagram and pin-to-signal-name mapping.
PH2
PH3
GND
VDD
PC0/TCK/SWCLK
PC1/TMS/SWDIO
PC2/TDI
PC3/TDO/SWO
CMOD1
PD5
PD4
GND
VDD
PB4/C0PB5/C1PB6/C0+
PB7/TRST
VDD25
GND
PH0/CCP6
PH1/CCP7
October 09, 2007
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
PE3/SSI1Tx
PE2/SSI1Rx
PE1/SSI1Fss
PE0/SSI1Clk
PB3/I2C0SDA
PB2/I2C0SCL
GND
VDD
PB1/CCP2
PB0/CCP0
CMOD0
RST
GND
VDD25
PF1
PF2
PF3
PF4/C0o
GND
VDD
VBAT
GND
XOSC1
XOSC0
HIB
PF5
PF0
OSC0
OSC1
WAKE
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
PA6/I2C1SCL
PA7/I2C1SDA
PG7
PG6
VDD25
GND
PG5
PG4
PF7
PF6
VDD
GND
LM3S1911
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
PA0/U0Rx
PA1/U0Tx
PA2/SSI0Clk
PA3/SSI0Fss
PA4/SSI0Rx
PA5/SSI0Tx
VDD
GND
PE7
PE6/C1o
VDDA
GNDA
PE5
PE4
LDO
VDD
GND
PD0
PD1
PD2/U1Rx
PD3/U1Tx
VDD25
GND
PG3
PG2
PG1/U2Tx
PG0/U2Rx
VDD
GND
PC7/CCP4
PC6/CCP3
PC5/C1+
PC4/CCP5
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
PD7/CCP1
PD6
VDDA
GNDA
Figure 16-1. Pin Connection Diagram
377
Preliminary
Signal Tables
17
Signal Tables
The following tables list the signals available for each pin. Functionality is enabled by software with
the GPIOAFSEL register.
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.
Table 17-1 on page 378 shows the pin-to-signal-name mapping, including functional characteristics
of the signals. Table 17-2 on page 382 lists the signals in alphabetical order by signal name.
Table 17-3 on page 386 groups the signals by functionality, except for GPIOs. Table 17-4 on page
390 lists the GPIO pins and their alternate functionality.
Table 17-1. Signals by Pin Number
Pin Number
Pin Name
Pin Type
1
PE7
I/O
Buffer Type Description
TTL
GPIO port E bit 7
2
PE6
I/O
TTL
GPIO port E bit 6
C1o
O
TTL
Analog comparator 1 output
3
VDDA
-
Power
The positive supply (3.3 V) for the analog
circuits (ADC, Analog Comparators, etc.).
These are separated from VDD to minimize
the electrical noise contained on VDD from
affecting the analog functions.
4
GNDA
-
Power
The ground reference for the analog circuits
(ADC, Analog Comparators, etc.). These are
separated from GND to minimize the electrical
noise contained on VDD from affecting the
analog functions.
5
PE5
I/O
TTL
GPIO port E bit 5
6
PE4
I/O
TTL
GPIO port E bit 4
7
LDO
-
Power
Low drop-out regulator output voltage. This
pin requires an external capacitor between
the pin and GND of 1 µF or greater. When the
on-chip LDO is used to provide power to the
logic, the LDO pin must also be connected to
the VDD25 pins at the board level in addition
to the decoupling capacitor(s).
8
VDD
-
Power
Positive supply for I/O and some logic.
Ground reference for logic and I/O pins.
9
GND
-
Power
10
PD0
I/O
TTL
GPIO port D bit 0
11
PD1
I/O
TTL
GPIO port D bit 1
12
13
14
PD2
I/O
TTL
GPIO port D bit 2
U1Rx
I
TTL
UART module 1 receive. When in IrDA mode,
this signal has IrDA modulation.
PD3
I/O
TTL
GPIO port D bit 3
U1Tx
O
TTL
UART module 1 transmit. When in IrDA mode,
this signal has IrDA modulation.
VDD25
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
378
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Pin Number
Pin Name
Pin Type
15
GND
-
Power
16
PG3
I/O
TTL
GPIO port G bit 3
17
PG2
I/O
TTL
GPIO port G bit 2
18
PG1
I/O
TTL
GPIO port G bit 1
U2Tx
O
TTL
UART 2 Transmit. When in IrDA mode, this
signal has IrDA modulation.
19
Buffer Type Description
Ground reference for logic and I/O pins.
PG0
I/O
TTL
GPIO port G bit 0
U2Rx
I
TTL
UART 2 Receive. When in IrDA mode, this
signal has IrDA modulation.
20
VDD
-
Power
Positive supply for I/O and some logic.
21
GND
-
Power
Ground reference for logic and I/O pins.
22
23
24
25
26
27
28
29
30
31
PC7
I/O
TTL
GPIO port C bit 7
CCP4
I/O
TTL
Capture/Compare/PWM 4
PC6
I/O
TTL
GPIO port C bit 6
CCP3
I/O
TTL
Capture/Compare/PWM 3
PC5
I/O
TTL
GPIO port C bit 5
C1+
I
Analog
PC4
I/O
TTL
GPIO port C bit 4
CCP5
I/O
TTL
Capture/Compare/PWM 5
Analog comparator positive input
PA0
I/O
TTL
GPIO port A bit 0
U0Rx
I
TTL
UART module 0 receive. When in IrDA mode,
this signal has IrDA modulation.
PA1
I/O
TTL
GPIO port A bit 1
U0Tx
O
TTL
UART module 0 transmit. When in IrDA mode,
this signal has IrDA modulation.
PA2
I/O
TTL
GPIO port A bit 2
SSI0Clk
I/O
TTL
SSI module 0 clock
PA3
I/O
TTL
GPIO port A bit 3
SSI0Fss
I/O
TTL
SSI module 0 frame
PA4
I/O
TTL
GPIO port A bit 4
SSI0Rx
I
TTL
SSI module 0 receive
PA5
I/O
TTL
GPIO port A bit 5
SSI0Tx
O
TTL
SSI module 0 transmit
32
VDD
-
Power
Positive supply for I/O and some logic.
33
GND
-
Power
Ground reference for logic and I/O pins.
34
PA6
I/O
TTL
GPIO port A bit 6
I2C1SCL
I/O
OD
I2C module 1 clock
PA7
I/O
TTL
GPIO port A bit 7
35
I2C1SDA
I/O
OD
I2C module 1 data
36
PG7
I/O
TTL
GPIO port G bit 7
37
PG6
I/O
TTL
GPIO port G bit 6
38
VDD25
-
Power
October 09, 2007
Positive supply for most of the logic function,
including the processor core and most
peripherals.
379
Preliminary
Signal Tables
Pin Number
Pin Name
Pin Type
39
GND
-
Power
40
PG5
I/O
TTL
GPIO port G bit 5
41
PG4
I/O
TTL
GPIO port G bit 4
42
PF7
I/O
TTL
GPIO port F bit 7
43
PF6
I/O
TTL
GPIO port F bit 6
44
VDD
-
Power
Positive supply for I/O and some logic.
45
GND
-
Power
Ground reference for logic and I/O pins.
46
PF5
I/O
TTL
GPIO port F bit 5
47
PF0
I/O
TTL
GPIO port F bit 0
48
OSC0
I
Analog
Main oscillator crystal input or an external
clock reference input.
49
OSC1
O
Analog
Main oscillator crystal output.
50
WAKE
I
OD
An external input that brings the processor out
of hibernate mode when asserted.
51
HIB
O
TTL
An output that indicates the processor is in
hibernate mode.
52
XOSC0
I
Analog
Hibernation Module oscillator crystal input or
an external clock reference input. Note that
this is either a 4.19-MHz crystal or a
32.768-kHz oscillator for the Hibernation
Module RTC. See the CLKSEL bit in the
HIBCTL register.
53
XOSC1
O
Analog
Hibernation Module oscillator crystal output.
54
GND
-
Power
Ground reference for logic and I/O pins.
55
VBAT
-
Power
Power source for the Hibernation Module. It
is normally connected to the positive terminal
of a battery and serves as the battery
backup/Hibernation Module power-source
supply.
56
VDD
-
Power
Positive supply for I/O and some logic.
57
GND
-
Power
Ground reference for logic and I/O pins.
58
PF4
I/O
TTL
GPIO port F bit 4
C0o
O
TTL
Analog comparator 0 output
59
PF3
I/O
TTL
GPIO port F bit 3
60
PF2
I/O
TTL
GPIO port F bit 2
61
PF1
I/O
TTL
GPIO port F bit 1
62
VDD25
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
63
GND
-
Power
Ground reference for logic and I/O pins.
64
RST
I
TTL
System reset input.
65
CMOD0
I/O
TTL
CPU Mode bit 0. Input must be set to logic 0
(grounded); other encodings reserved.
66
67
Buffer Type Description
Ground reference for logic and I/O pins.
PB0
I/O
TTL
GPIO port B bit 0
CCP0
I/O
TTL
Capture/Compare/PWM 0
PB1
I/O
TTL
GPIO port B bit 1
CCP2
I/O
TTL
Capture/Compare/PWM 2
380
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Pin Number
Pin Name
Pin Type
68
VDD
-
Power
Positive supply for I/O and some logic.
69
GND
-
Power
Ground reference for logic and I/O pins.
70
71
72
73
74
75
Buffer Type Description
PB2
I/O
TTL
GPIO port B bit 2
I2C0SCL
I/O
OD
I2C module 0 clock
PB3
I/O
TTL
GPIO port B bit 3
I2C0SDA
I/O
OD
I2C module 0 data
PE0
I/O
TTL
GPIO port E bit 0
SSI1Clk
I/O
TTL
SSI module 1 clock
PE1
I/O
TTL
GPIO port E bit 1
SSI1Fss
I/O
TTL
SSI module 1 frame
PE2
I/O
TTL
GPIO port E bit 2
SSI1Rx
I
TTL
SSI module 1 receive
PE3
I/O
TTL
GPIO port E bit 3
SSI1Tx
O
TTL
SSI module 1 transmit
76
CMOD1
I/O
TTL
CPU Mode bit 1. Input must be set to logic 0
(grounded); other encodings reserved.
77
PC3
I/O
TTL
GPIO port C bit 3
TDO
O
TTL
JTAG TDO and SWO
SWO
O
TTL
JTAG TDO and SWO
PC2
I/O
TTL
GPIO port C bit 2
TDI
I
TTL
JTAG TDI
PC1
I/O
TTL
GPIO port C bit 1
78
79
TMS
I/O
TTL
JTAG TMS and SWDIO
SWDIO
I/O
TTL
JTAG TMS and SWDIO
PC0
I/O
TTL
GPIO port C bit 0
TCK
I
TTL
JTAG/SWD CLK
SWCLK
I
TTL
JTAG/SWD CLK
81
VDD
-
Power
Positive supply for I/O and some logic.
82
GND
-
Power
Ground reference for logic and I/O pins.
83
PH3
I/O
TTL
GPIO port H bit 3
84
PH2
I/O
TTL
GPIO port H bit 2
85
PH1
I/O
TTL
GPIO port H bit 1
CCP7
I/O
TTL
Capture/Compare/PWM 7
PH0
I/O
TTL
GPIO port H bit 0
CCP6
I/O
TTL
Capture/Compare/PWM 6
87
GND
-
Power
Ground reference for logic and I/O pins.
88
VDD25
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
80
86
89
90
PB7
I/O
TTL
GPIO port B bit 7
TRST
I
TTL
JTAG TRSTn
PB6
I/O
TTL
GPIO port B bit 6
C0+
I
Analog
October 09, 2007
Analog comparator 0 positive input
381
Preliminary
Signal Tables
Pin Number
Pin Name
Pin Type
91
PB5
I/O
TTL
C1-
I
Analog
PB4
I/O
TTL
C0-
I
Analog
Analog comparator 0 negative input
93
VDD
-
Power
Positive supply for I/O and some logic.
94
GND
-
Power
Ground reference for logic and I/O pins.
95
PD4
I/O
TTL
GPIO port D bit 4
96
PD5
I/O
TTL
GPIO port D bit 5
97
GNDA
-
Power
The ground reference for the analog circuits
(ADC, Analog Comparators, etc.). These are
separated from GND to minimize the electrical
noise contained on VDD from affecting the
analog functions.
98
VDDA
-
Power
The positive supply (3.3 V) for the analog
circuits (ADC, Analog Comparators, etc.).
These are separated from VDD to minimize
the electrical noise contained on VDD from
affecting the analog functions.
99
PD6
I/O
TTL
GPIO port D bit 6
100
PD7
I/O
TTL
GPIO port D bit 7
CCP1
I/O
TTL
Capture/Compare/PWM 1
92
Buffer Type Description
GPIO port B bit 5
Analog comparator 1 negative input
GPIO port B bit 4
Table 17-2. Signals by Signal Name
Pin Name
Pin Number
Pin Type
C0+
90
I
Analog
Analog comparator 0 positive input
C0-
92
I
Analog
Analog comparator 0 negative input
C0o
58
O
TTL
C1+
24
I
Analog
Analog comparator positive input
C1-
91
I
Analog
Analog comparator 1 negative input
C1o
2
O
TTL
Analog comparator 1 output
CCP0
66
I/O
TTL
Capture/Compare/PWM 0
CCP1
100
I/O
TTL
Capture/Compare/PWM 1
CCP2
67
I/O
TTL
Capture/Compare/PWM 2
CCP3
23
I/O
TTL
Capture/Compare/PWM 3
CCP4
22
I/O
TTL
Capture/Compare/PWM 4
CCP5
25
I/O
TTL
Capture/Compare/PWM 5
CCP6
86
I/O
TTL
Capture/Compare/PWM 6
CCP7
85
I/O
TTL
Capture/Compare/PWM 7
CMOD0
65
I/O
TTL
CPU Mode bit 0. Input must be set to logic 0
(grounded); other encodings reserved.
CMOD1
76
I/O
TTL
CPU Mode bit 1. Input must be set to logic 0
(grounded); other encodings reserved.
GND
9
-
Power
Ground reference for logic and I/O pins.
GND
15
-
Power
Ground reference for logic and I/O pins.
GND
21
-
Power
Ground reference for logic and I/O pins.
382
Buffer Type Description
Analog comparator 0 output
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Pin Name
Pin Number
Pin Type
GND
33
-
Buffer Type Description
Power
Ground reference for logic and I/O pins.
GND
39
-
Power
Ground reference for logic and I/O pins.
GND
45
-
Power
Ground reference for logic and I/O pins.
GND
54
-
Power
Ground reference for logic and I/O pins.
GND
57
-
Power
Ground reference for logic and I/O pins.
GND
63
-
Power
Ground reference for logic and I/O pins.
GND
69
-
Power
Ground reference for logic and I/O pins.
GND
82
-
Power
Ground reference for logic and I/O pins.
GND
87
-
Power
Ground reference for logic and I/O pins.
GND
94
-
Power
Ground reference for logic and I/O pins.
GNDA
4
-
Power
The ground reference for the analog circuits
(ADC, Analog Comparators, etc.). These are
separated from GND to minimize the electrical
noise contained on VDD from affecting the
analog functions.
GNDA
97
-
Power
The ground reference for the analog circuits
(ADC, Analog Comparators, etc.). These are
separated from GND to minimize the electrical
noise contained on VDD from affecting the
analog functions.
HIB
51
O
TTL
An output that indicates the processor is in
hibernate mode.
I2C0SCL
70
I/O
OD
I2C module 0 clock
I2C0SDA
71
I/O
OD
I2C module 0 data
I2C1SCL
34
I/O
OD
I2C module 1 clock
I2C1SDA
35
I/O
OD
I2C module 1 data
LDO
7
-
Power
Low drop-out regulator output voltage. This
pin requires an external capacitor between
the pin and GND of 1 µF or greater. When the
on-chip LDO is used to provide power to the
logic, the LDO pin must also be connected to
the VDD25 pins at the board level in addition
to the decoupling capacitor(s).
OSC0
48
I
Analog
Main oscillator crystal input or an external
clock reference input.
OSC1
49
O
Analog
Main oscillator crystal output.
PA0
26
I/O
TTL
GPIO port A bit 0
PA1
27
I/O
TTL
GPIO port A bit 1
PA2
28
I/O
TTL
GPIO port A bit 2
PA3
29
I/O
TTL
GPIO port A bit 3
PA4
30
I/O
TTL
GPIO port A bit 4
PA5
31
I/O
TTL
GPIO port A bit 5
PA6
34
I/O
TTL
GPIO port A bit 6
PA7
35
I/O
TTL
GPIO port A bit 7
PB0
66
I/O
TTL
GPIO port B bit 0
PB1
67
I/O
TTL
GPIO port B bit 1
PB2
70
I/O
TTL
GPIO port B bit 2
October 09, 2007
383
Preliminary
Signal Tables
Pin Name
Pin Number
Pin Type
PB3
71
I/O
TTL
GPIO port B bit 3
PB4
92
I/O
TTL
GPIO port B bit 4
PB5
91
I/O
TTL
GPIO port B bit 5
PB6
90
I/O
TTL
GPIO port B bit 6
PB7
89
I/O
TTL
GPIO port B bit 7
PC0
80
I/O
TTL
GPIO port C bit 0
PC1
79
I/O
TTL
GPIO port C bit 1
PC2
78
I/O
TTL
GPIO port C bit 2
PC3
77
I/O
TTL
GPIO port C bit 3
PC4
25
I/O
TTL
GPIO port C bit 4
PC5
24
I/O
TTL
GPIO port C bit 5
PC6
23
I/O
TTL
GPIO port C bit 6
PC7
22
I/O
TTL
GPIO port C bit 7
PD0
10
I/O
TTL
GPIO port D bit 0
PD1
11
I/O
TTL
GPIO port D bit 1
PD2
12
I/O
TTL
GPIO port D bit 2
PD3
13
I/O
TTL
GPIO port D bit 3
PD4
95
I/O
TTL
GPIO port D bit 4
PD5
96
I/O
TTL
GPIO port D bit 5
PD6
99
I/O
TTL
GPIO port D bit 6
PD7
100
I/O
TTL
GPIO port D bit 7
PE0
72
I/O
TTL
GPIO port E bit 0
PE1
73
I/O
TTL
GPIO port E bit 1
PE2
74
I/O
TTL
GPIO port E bit 2
PE3
75
I/O
TTL
GPIO port E bit 3
PE4
6
I/O
TTL
GPIO port E bit 4
PE5
5
I/O
TTL
GPIO port E bit 5
PE6
2
I/O
TTL
GPIO port E bit 6
PE7
1
I/O
TTL
GPIO port E bit 7
PF0
47
I/O
TTL
GPIO port F bit 0
PF1
61
I/O
TTL
GPIO port F bit 1
PF2
60
I/O
TTL
GPIO port F bit 2
PF3
59
I/O
TTL
GPIO port F bit 3
PF4
58
I/O
TTL
GPIO port F bit 4
PF5
46
I/O
TTL
GPIO port F bit 5
PF6
43
I/O
TTL
GPIO port F bit 6
PF7
42
I/O
TTL
GPIO port F bit 7
PG0
19
I/O
TTL
GPIO port G bit 0
PG1
18
I/O
TTL
GPIO port G bit 1
PG2
17
I/O
TTL
GPIO port G bit 2
PG3
16
I/O
TTL
GPIO port G bit 3
PG4
41
I/O
TTL
GPIO port G bit 4
384
Buffer Type Description
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Pin Name
Pin Number
Pin Type
PG5
40
I/O
Buffer Type Description
TTL
GPIO port G bit 5
PG6
37
I/O
TTL
GPIO port G bit 6
PG7
36
I/O
TTL
GPIO port G bit 7
PH0
86
I/O
TTL
GPIO port H bit 0
PH1
85
I/O
TTL
GPIO port H bit 1
PH2
84
I/O
TTL
GPIO port H bit 2
PH3
83
I/O
TTL
GPIO port H bit 3
RST
64
I
TTL
System reset input.
SSI0Clk
28
I/O
TTL
SSI module 0 clock
SSI0Fss
29
I/O
TTL
SSI module 0 frame
SSI0Rx
30
I
TTL
SSI module 0 receive
SSI0Tx
31
O
TTL
SSI module 0 transmit
SSI1Clk
72
I/O
TTL
SSI module 1 clock
SSI1Fss
73
I/O
TTL
SSI module 1 frame
SSI1Rx
74
I
TTL
SSI module 1 receive
SSI1Tx
75
O
TTL
SSI module 1 transmit
SWCLK
80
I
TTL
JTAG/SWD CLK
SWDIO
79
I/O
TTL
JTAG TMS and SWDIO
SWO
77
O
TTL
JTAG TDO and SWO
TCK
80
I
TTL
JTAG/SWD CLK
TDI
78
I
TTL
JTAG TDI
TDO
77
O
TTL
JTAG TDO and SWO
TMS
79
I/O
TTL
JTAG TMS and SWDIO
TRST
89
I
TTL
JTAG TRSTn
U0Rx
26
I
TTL
UART module 0 receive. When in IrDA mode,
this signal has IrDA modulation.
U0Tx
27
O
TTL
UART module 0 transmit. When in IrDA mode,
this signal has IrDA modulation.
U1Rx
12
I
TTL
UART module 1 receive. When in IrDA mode,
this signal has IrDA modulation.
U1Tx
13
O
TTL
UART module 1 transmit. When in IrDA mode,
this signal has IrDA modulation.
U2Rx
19
I
TTL
UART 2 Receive. When in IrDA mode, this
signal has IrDA modulation.
U2Tx
18
O
TTL
UART 2 Transmit. When in IrDA mode, this
signal has IrDA modulation.
VBAT
55
-
Power
Power source for the Hibernation Module. It
is normally connected to the positive terminal
of a battery and serves as the battery
backup/Hibernation Module power-source
supply.
VDD
8
-
Power
Positive supply for I/O and some logic.
VDD
20
-
Power
Positive supply for I/O and some logic.
VDD
32
-
Power
Positive supply for I/O and some logic.
VDD
44
-
Power
Positive supply for I/O and some logic.
VDD
56
-
Power
Positive supply for I/O and some logic.
October 09, 2007
385
Preliminary
Signal Tables
Pin Name
Pin Number
Pin Type
VDD
68
-
Buffer Type Description
Power
Positive supply for I/O and some logic.
VDD
81
-
Power
Positive supply for I/O and some logic.
VDD
93
-
Power
Positive supply for I/O and some logic.
VDD25
14
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
VDD25
38
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
VDD25
62
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
VDD25
88
-
Power
Positive supply for most of the logic function,
including the processor core and most
peripherals.
VDDA
3
-
Power
The positive supply (3.3 V) for the analog
circuits (ADC, Analog Comparators, etc.).
These are separated from VDD to minimize
the electrical noise contained on VDD from
affecting the analog functions.
VDDA
98
-
Power
The positive supply (3.3 V) for the analog
circuits (ADC, Analog Comparators, etc.).
These are separated from VDD to minimize
the electrical noise contained on VDD from
affecting the analog functions.
WAKE
50
I
OD
An external input that brings the processor out
of hibernate mode when asserted.
XOSC0
52
I
Analog
Hibernation Module oscillator crystal input or
an external clock reference input. Note that
this is either a 4.19-MHz crystal or a
32.768-kHz oscillator for the Hibernation
Module RTC. See the CLKSEL bit in the
HIBCTL register.
XOSC1
53
O
Analog
Hibernation Module oscillator crystal output.
Table 17-3. Signals by Function, Except for GPIO
Function
Analog
Comparators
Pin Name
Pin
Number
Pin Type
Buffer
Type
C0+
90
I
Analog
Analog comparator 0 positive input
C0-
92
I
Analog
Analog comparator 0 negative input
C0o
58
O
TTL
C1+
24
I
Analog
Analog comparator positive input
C1-
91
I
Analog
Analog comparator 1 negative input
C1o
2
O
TTL
386
Description
Analog comparator 0 output
Analog comparator 1 output
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Function
Pin Name
Pin
Number
Pin Type
Buffer
Type
Description
General-Purpose CCP0
Timers
CCP1
66
I/O
TTL
Capture/Compare/PWM 0
100
I/O
TTL
Capture/Compare/PWM 1
CCP2
67
I/O
TTL
Capture/Compare/PWM 2
CCP3
23
I/O
TTL
Capture/Compare/PWM 3
CCP4
22
I/O
TTL
Capture/Compare/PWM 4
CCP5
25
I/O
TTL
Capture/Compare/PWM 5
CCP6
86
I/O
TTL
Capture/Compare/PWM 6
CCP7
85
I/O
TTL
Capture/Compare/PWM 7
I2C0SCL
70
I/O
OD
I2C module 0 clock
I2C0SDA
71
I/O
OD
I2C module 0 data
I2C1SCL
34
I/O
OD
I2C module 1 clock
I2C1SDA
I2C
35
I/O
OD
I2C module 1 data
JTAG/SWD/SWO SWCLK
80
I
TTL
JTAG/SWD CLK
SWDIO
79
I/O
TTL
JTAG TMS and SWDIO
SWO
77
O
TTL
JTAG TDO and SWO
TCK
80
I
TTL
JTAG/SWD CLK
TDI
78
I
TTL
JTAG TDI
TDO
77
O
TTL
JTAG TDO and SWO
TMS
79
I/O
TTL
JTAG TMS and SWDIO
October 09, 2007
387
Preliminary
Signal Tables
Function
Power
Pin Name
Pin
Number
Pin Type
Buffer
Type
GND
9
-
Power
Ground reference for logic and I/O pins.
GND
15
-
Power
Ground reference for logic and I/O pins.
GND
21
-
Power
Ground reference for logic and I/O pins.
GND
33
-
Power
Ground reference for logic and I/O pins.
GND
39
-
Power
Ground reference for logic and I/O pins.
GND
45
-
Power
Ground reference for logic and I/O pins.
GND
54
-
Power
Ground reference for logic and I/O pins.
GND
57
-
Power
Ground reference for logic and I/O pins.
GND
63
-
Power
Ground reference for logic and I/O pins.
GND
69
-
Power
Ground reference for logic and I/O pins.
GND
82
-
Power
Ground reference for logic and I/O pins.
GND
87
-
Power
Ground reference for logic and I/O pins.
GND
94
-
Power
Ground reference for logic and I/O pins.
GNDA
4
-
Power
The ground reference for the analog circuits (ADC,
Analog Comparators, etc.). These are separated
from GND to minimize the electrical noise contained
on VDD from affecting the analog functions.
GNDA
97
-
Power
The ground reference for the analog circuits (ADC,
Analog Comparators, etc.). These are separated
from GND to minimize the electrical noise contained
on VDD from affecting the analog functions.
HIB
51
O
TTL
LDO
7
-
Power
Low drop-out regulator output voltage. This pin
requires an external capacitor between the pin and
GND of 1 µF or greater. When the on-chip LDO is
used to provide power to the logic, the LDO pin
must also be connected to the VDD25 pins at the
board level in addition to the decoupling
capacitor(s).
VBAT
55
-
Power
Power source for the Hibernation Module. It is
normally connected to the positive terminal of a
battery and serves as the battery
backup/Hibernation Module power-source supply.
VDD
8
-
Power
Positive supply for I/O and some logic.
VDD
20
-
Power
Positive supply for I/O and some logic.
VDD
32
-
Power
Positive supply for I/O and some logic.
VDD
44
-
Power
Positive supply for I/O and some logic.
VDD
56
-
Power
Positive supply for I/O and some logic.
VDD
68
-
Power
Positive supply for I/O and some logic.
VDD
81
-
Power
Positive supply for I/O and some logic.
VDD
93
-
Power
Positive supply for I/O and some logic.
VDD25
14
-
Power
Positive supply for most of the logic function,
including the processor core and most peripherals.
VDD25
38
-
Power
Positive supply for most of the logic function,
including the processor core and most peripherals.
VDD25
62
-
Power
Positive supply for most of the logic function,
including the processor core and most peripherals.
388
Description
An output that indicates the processor is in
hibernate mode.
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Function
Pin
Number
Pin Type
Buffer
Type
Description
VDD25
88
-
Power
Positive supply for most of the logic function,
including the processor core and most peripherals.
VDDA
3
-
Power
The positive supply (3.3 V) for the analog circuits
(ADC, Analog Comparators, etc.). These are
separated from VDD to minimize the electrical noise
contained on VDD from affecting the analog
functions.
VDDA
98
-
Power
The positive supply (3.3 V) for the analog circuits
(ADC, Analog Comparators, etc.). These are
separated from VDD to minimize the electrical noise
contained on VDD from affecting the analog
functions.
WAKE
50
I
OD
An external input that brings the processor out of
hibernate mode when asserted.
SSI0Clk
28
I/O
TTL
SSI module 0 clock
SSI0Fss
29
I/O
TTL
SSI module 0 frame
SSI0Rx
30
I
TTL
SSI module 0 receive
SSI0Tx
31
O
TTL
SSI module 0 transmit
SSI1Clk
72
I/O
TTL
SSI module 1 clock
SSI1Fss
73
I/O
TTL
SSI module 1 frame
SSI1Rx
74
I
TTL
SSI module 1 receive
SSI1Tx
75
O
TTL
SSI module 1 transmit
System Control & CMOD0
Clocks
65
I/O
TTL
CPU Mode bit 0. Input must be set to logic 0
(grounded); other encodings reserved.
CMOD1
76
I/O
TTL
CPU Mode bit 1. Input must be set to logic 0
(grounded); other encodings reserved.
OSC0
48
I
Analog
Main oscillator crystal input or an external clock
reference input.
OSC1
49
O
Analog
Main oscillator crystal output.
RST
64
I
TTL
System reset input.
TRST
89
I
TTL
JTAG TRSTn
XOSC0
52
I
Analog
Hibernation Module oscillator crystal input or an
external clock reference input. Note that this is
either a 4.19-MHz crystal or a 32.768-kHz oscillator
for the Hibernation Module RTC. See the CLKSEL
bit in the HIBCTL register.
XOSC1
53
O
Analog
Hibernation Module oscillator crystal output.
U0Rx
26
I
TTL
UART module 0 receive. When in IrDA mode, this
signal has IrDA modulation.
U0Tx
27
O
TTL
UART module 0 transmit. When in IrDA mode, this
signal has IrDA modulation.
U1Rx
12
I
TTL
UART module 1 receive. When in IrDA mode, this
signal has IrDA modulation.
U1Tx
13
O
TTL
UART module 1 transmit. When in IrDA mode, this
signal has IrDA modulation.
U2Rx
19
I
TTL
UART 2 Receive. When in IrDA mode, this signal
has IrDA modulation.
U2Tx
18
O
TTL
UART 2 Transmit. When in IrDA mode, this signal
has IrDA modulation.
SSI
UART
Pin Name
October 09, 2007
389
Preliminary
Signal Tables
Table 17-4. GPIO Pins and Alternate Functions
GPIO Pin
Pin Number
Multiplexed Function
PA0
26
U0Rx
PA1
27
U0Tx
PA2
28
SSI0Clk
PA3
29
SSI0Fss
PA4
30
SSI0Rx
PA5
31
SSI0Tx
PA6
34
I2C1SCL
PA7
35
I2C1SDA
PB0
66
CCP0
PB1
67
CCP2
PB2
70
I2C0SCL
PB3
71
I2C0SDA
PB4
92
C0-
PB5
91
C1-
PB6
90
C0+
PB7
89
TRST
PC0
80
TCK
SWCLK
PC1
79
TMS
SWDIO
PC2
78
TDI
PC3
77
TDO
PC4
25
CCP5
PC5
24
C1+
PC6
23
CCP3
PC7
22
CCP4
PD0
10
PD1
11
PD2
12
U1Rx
PD3
13
U1Tx
PD4
95
PD5
96
PD6
99
PD7
100
CCP1
PE0
72
SSI1Clk
PE1
73
SSI1Fss
PE2
74
SSI1Rx
PE3
75
SSI1Tx
PE4
6
PE5
5
PE6
2
PE7
1
PF0
47
Multiplexed Function
SWO
C1o
390
October 09, 2007
Preliminary
LM3S1911 Microcontroller
GPIO Pin
Pin Number
PF1
61
PF2
60
PF3
59
PF4
58
PF5
46
PF6
43
PF7
42
PG0
19
U2Rx
PG1
18
U2Tx
PG2
17
PG3
16
PG4
41
PG5
40
PG6
37
PG7
36
PH0
86
CCP6
PH1
85
CCP7
PH2
84
PH3
83
October 09, 2007
Multiplexed Function
Multiplexed Function
C0o
391
Preliminary
Operating Characteristics
18
Operating Characteristics
Table 18-1. Temperature Characteristics
Characteristic
Symbol Value
a
Operating temperature range TA
-40 to +85
Unit
°C
a. Maximum storage temperature is 150°C.
Table 18-2. Thermal Characteristics
Characteristic
Symbol Value
a
Thermal resistance (junction to ambient) ΘJA
b
Average junction temperature
TJ
55.3
TA + (PAVG • ΘJA)
Unit
°C/W
°C
a. Junction to ambient thermal resistance θJA numbers are determined by a package simulator.
b. Power dissipation is a function of temperature.
392
October 09, 2007
Preliminary
LM3S1911 Microcontroller
19
Electrical Characteristics
19.1
DC Characteristics
19.1.1
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.
Table 19-1. Maximum Ratings
Characteristic
a
Symbol
Value
Unit
Min Max
I/O supply voltage (VDD)
VDD
0
4
V
Core supply voltage (VDD25)
VDD25
0
4
V
Analog supply voltage (VDDA)
VDDA
0
4
V
Battery supply voltage (VBAT)
VBAT
0
4
V
Input voltage
VIN
Maximum current per output pins
I
-0.3 5.5
-
25
V
mA
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. Recommended DC Operating Conditions
Parameter Parameter Name
Min
Nom
Max
Unit
I/O supply voltage
3.0
3.3
3.6
V
VDD25
Core supply voltage
2.25
2.5
2.75
V
VDDA
Analog supply voltage
3.0
3.3
3.6
V
VBAT
Battery supply voltage
2.3
3.0
3.6
V
VIH
High-level input voltage
2.0
-
5.0
V
VIL
Low-level input voltage
-0.3
VDD
-
1.3
V
VSIH
High-level input voltage for Schmitt trigger inputs 0.8 * VDD
-
VDD
V
VSIL
Low-level input voltage for Schmitt trigger inputs
0
-
0.2 * VDD
V
VOH
High-level output voltage
2.4
-
-
V
VOL
Low-level output voltage
-
-
0.4
V
IOH
High-level source current, VOH=2.4 V
2-mA Drive
2.0
-
-
mA
4-mA Drive
4.0
-
-
mA
8-mA Drive
8.0
-
-
mA
October 09, 2007
393
Preliminary
Electrical Characteristics
Parameter Parameter Name
IOL
19.1.3
Min
Nom
Max
Unit
2-mA Drive
2.0
-
-
mA
4-mA Drive
4.0
-
-
mA
8-mA Drive
8.0
-
-
mA
Low-level sink current, VOL=0.4 V
On-Chip Low Drop-Out (LDO) Regulator Characteristics
Table 19-3. LDO Regulator Characteristics
Parameter Parameter Name
VLDOOUT
19.1.4
Min Nom Max Unit
Programmable internal (logic) power supply output value 2.25 2.5 2.75
V
Output voltage accuracy
-
2%
-
%
tPON
Power-on time
-
-
100
µs
tON
Time on
-
-
200
µs
tOFF
Time off
-
-
100
µs
VSTEP
Step programming incremental voltage
-
50
-
mV
CLDO
External filter capacitor size for internal power supply
1.0
-
3.0
µF
Power Specifications
The power measurements specified in the tables that follow are run on the core processor using
SRAM with the following specifications (except as noted):
■ VDD = 3.3 V
■ VDD25 = 2.50 V
■ VBAT = 3.0 V
■ VDDA = 3.3 V
■ Temperature = 25°C
■ Clock Source (MOSC) =3.579545 MHz Crystal Oscillator
■ Main oscillator (MOSC) = enabled
■ Internal oscillator (IOSC) = disabled
394
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Table 19-4. Detailed Power Specifications
Parameter
Parameter
Name
Conditions
3.3 V VDD, VDDA,
VDDPHY
Nom
IDD_RUN
Run mode 1
(Flash loop)
VDD25 = 2.50 V
Max
a
2.5 V VDD25
3.0 V VBAT
Unit
Nom
Max
Nom
Max
0
pendinga mA
3
pending
108
pendinga
0
pendinga
53
pendinga
0
pendinga mA
3
pendinga
102 pendinga
0
pendinga mA
0
pendinga
47
pendinga
0
pendinga mA
0
pendinga
17
pendinga
0
pendinga mA
pendinga 0.18 pendinga
0
pendinga mA
pendinga
16
pendinga µA
Code= while(1){} executed in
Flash
Peripherals = All ON
System Clock = 50 MHz (with
PLL)
Run mode 2
(Flash loop)
VDD25 = 2.50 V
Code= while(1){} executed in
Flash
Peripherals = All OFF
System Clock = 50 MHz (with
PLL)
Run mode 1
(SRAM loop)
VDD25 = 2.50 V
Code= while(1){} executed in
SRAM
Peripherals = All ON
System Clock = 50 MHz (with
PLL)
Run mode 2
(SRAM loop)
VDD25 = 2.50 V
Code= while(1){} executed in
SRAM
Peripherals = All OFF
System Clock = 50 MHz (with
PLL)
IDD_SLEEP
Sleep mode
VDD25 = 2.50 V
Peripherals = All OFF
System Clock = 50 MHz (with
PLL)
IDD_DEEPSLEEP Deep-Sleep
mode
LDO = 2.25 V
0.14
Peripherals = All OFF
System Clock = IOSC30KHZ/64
IDD_HIBERNATE Hibernate
mode
VBAT = 3.0 V
0
0
pendinga
VDD = 0 V
VDD25 = 0 V
VDDA = 0 V
VDDPHY = 0 V
Peripherals = All OFF
System Clock = OFF
Hibernate Module = 32 kHz
a. Pending characterization completion.
October 09, 2007
395
Preliminary
Electrical Characteristics
19.1.5
Flash Memory Characteristics
Table 19-5. Flash Memory Characteristics
Parameter Parameter Name
PECYC
TRET
Min
Nom
a
Max Unit
Number of guaranteed program/erase cycles before failure 10,000 100,000
-
cycles
Data retention at average operating temperature of 85˚C
10
-
-
years
TPROG
Word program time
20
-
-
µs
TERASE
Page erase time
20
-
-
ms
TME
Mass erase time
200
-
-
ms
a. A program/erase cycle is defined as switching the bits from 1-> 0 -> 1.
19.2
AC Characteristics
19.2.1
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
CL = 50 pF
pin
GND
19.2.2
Clocks
Table 19-6. Phase Locked Loop (PLL) Characteristics
Parameter Parameter Name
fref_crystal
fref_ext
a
Crystal reference
referencea
External clock
b
Min
Nom Max Unit
3.579545
-
8.192 MHz
3.579545
-
8.192 MHz
fpll
PLL frequency
-
400
-
MHz
TREADY
PLL lock time
-
-
0.5
ms
a. The exact value is determined by the crystal value programmed into the XTAL field of the Run-Mode Clock Configuration
(RCC) register.
b. PLL frequency is automatically calculated by the hardware based on the XTAL field of the RCC register.
Table 19-7. Clock Characteristics
Parameter Name
Min
Nom
Max Unit
fIOSC
Parameter
Internal 12 MHz oscillator frequency
8.4
12
15.6 MHz
fIOSC30KHZ
Internal 30 KHz oscillator frequency
21
30
39
KHz
fXOSC
Hibernation module oscillator frequency
-
4.194304
-
MHz
fXOSC_XTAL
Crystal reference for hibernation oscillator
-
4.194304
-
MHz
fXOSC_EXT
External clock reference for hibernation module
-
32.768
-
KHz
396
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Parameter
Parameter Name
Min
Nom
1
-
8
MHz
125
-
1000
ns
fref_crystal_bypass Crystal reference using the main oscillator (PLL in BYPASS mode)
1
-
8
MHz
fref_ext_bypass
External clock reference (PLL in BYPASS mode)
0
-
50
MHz
fsystem_clock
System clock
0
-
50
MHz
fMOSC
Main oscillator frequency
tMOSC_per
Main oscillator period
Max Unit
Table 19-8. Crystal Characteristics
Parameter Name
Value
Frequency
Frequency tolerance
Aging
Oscillation mode
19.2.3
Units
8
6
4
3.5
MHz
±50
±50
±50
±50
ppm
±5
±5
±5
±5
ppm/yr
Parallel Parallel Parallel Parallel
Temperature stability (0 - 85 °C)
±25
±25
±25
±25
ppm
Motional capacitance (typ)
27.8
37.0
55.6
63.5
pF
Motional inductance (typ)
14.3
19.1
28.6
32.7
mH
Equivalent series resistance (max)
120
160
200
220
Ω
Shunt capacitance (max)
10
10
10
10
pF
Load capacitance (typ)
16
16
16
16
pF
Drive level (typ)
100
100
100
100
µW
Analog Comparator
Table 19-9. Analog Comparator Characteristics
Parameter Parameter Name
Min Nom
Max
Unit
VOS
Input offset voltage
-
±10
±25
mV
VCM
Input common mode voltage range
0
-
VDD-1.5
V
CMRR
Common mode rejection ratio
50
-
-
dB
TRT
Response time
-
-
1
µs
TMC
Comparator mode change to Output Valid
-
-
10
µs
Table 19-10. Analog Comparator Voltage Reference Characteristics
Parameter Parameter Name
19.2.4
Min Nom Max Unit
RHR
Resolution high range
-
VDD/32
-
LSB
RLR
Resolution low range
-
VDD/24
-
LSB
AHR
Absolute accuracy high range
-
-
±1/2 LSB
ALR
Absolute accuracy low range
-
-
±1/4 LSB
I2C
Table 19-11. I2C Characteristics
Parameter No. Parameter Parameter Name
a
tSCH
a
tLP
I1
I2
Max
Unit
Start condition hold time
36
-
-
system clocks
Clock Low period
36
-
-
system clocks
October 09, 2007
Min Nom
397
Preliminary
Electrical Characteristics
Parameter No. Parameter Parameter Name
Max
Unit
b
tSRT
I2CSCL/I2CSDA rise time (VIL =0.5 V to V IH =2.4 V)
-
-
(see note b)
ns
a
tDH
Data hold time
2
-
-
system clocks
c
tSFT
I2CSCL/I2CSDA fall time (VIH =2.4 V to V IL =0.5 V)
-
9
10
ns
a
tHT
Clock High time
24
-
-
system clocks
a
tDS
Data setup time
18
-
-
system clocks
a
tSCSR
Start condition setup time (for repeated start condition 36
only)
-
-
system clocks
a
tSCS
Stop condition setup time
-
-
system clocks
I3
I4
I5
I6
I7
I8
I9
Min Nom
24
I2C
a. Values depend on the value programmed into the TPR bit in the
Master Timer Period (I2CMTPR) register; a TPR
programmed for the maximum I2CSCL frequency (TPR=0x2) results in a minimum output timing as shown in the table
above. The I 2C interface is designed to scale the actual data transition time to move it to the middle of the I2CSCL Low
period. The actual position is affected by the value programmed into the TPR; however, the numbers given in the above
values are minimum values.
b. Because I2CSCL and I2CSDA are open-drain-type outputs, which the controller can only actively drive Low, the time
I2CSCL or I2CSDA takes to reach a high level depends on external signal capacitance and pull-up resistor values.
c. Specified at a nominal 50 pF load.
Figure 19-2. I2C Timing
I2
I6
I5
I2CSCL
I1
I4
I7
I8
I3
I9
I2CSDA
19.2.5
Hibernation Module
The Hibernation Module requires special system implementation considerations since it is intended
to power-down all other sections of its host device. The system power-supply distribution and
interfaces of the system must be driven to 0 VDC or powered down with the same regulator controlled
by HIB.
The regulators controlled by HIB are expected to have a settling time of 250 μs or less.
Table 19-12. Hibernation Module Characteristics
Parameter No
Parameter
H1
tHIB_LOW
Internal 32.768 KHz clock reference rising edge to /HIB asserted
-
200
-
μs
H2
tHIB_HIGH
Internal 32.768 KHz clock reference rising edge to /HIB deasserted
-
30
-
μs
62
-
-
μs
62
-
124
μs
20
-
-
ms
H6
tHIB_REG_WRITE Time for a write to non-volatile registers in HIB module to complete 92
-
-
μs
H7
tHIB_TO_VDD
-
250
μs
H3
H4
H5
Parameter Name
tWAKE_ASSERT /WAKE assertion time
tWAKETOHIB
/WAKE assert to /HIB desassert
a
tXOSC_SETTLE XOSC settling time
HIB deassert to VDD and VDD25 at minimum operational level
Min Nom Max Unit
-
a. This parameter is highly sensitive to PCB layout and trace lengths, which may make this parameter time longer. Care
must be taken in PCB design to minimize trace lengths and RLC (resistance, inductance, capacitance).
398
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Figure 19-3. Hibernation Module Timing
32.768 KHz
(internal)
H1
H2
/HIB
H4
/WAKE
H3
19.2.6
Synchronous Serial Interface (SSI)
Table 19-13. SSI Characteristics
Parameter No. Parameter Parameter Name
Min Nom Max
Unit
S1
tclk_per
SSIClk cycle time
2
-
65024 system clocks
S2
tclk_high
SSIClk high time
-
1/2
-
t clk_per
S3
tclk_low
SSIClk low time
-
1/2
-
t clk_per
S4
tclkrf
SSIClk rise/fall time
-
7.4
26
ns
S5
tDMd
Data from master valid delay time
0
-
20
ns
S6
tDMs
Data from master setup time
20
-
-
ns
S7
tDMh
Data from master hold time
40
-
-
ns
S8
tDSs
Data from slave setup time
20
-
-
ns
S9
tDSh
Data from slave hold time
40
-
-
ns
Figure 19-4. SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement
S1
S4
S2
SSIClk
S3
SSIFss
SSITx
SSIRx
MSB
LSB
4 to 16 bits
October 09, 2007
399
Preliminary
Electrical Characteristics
Figure 19-5. SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer
S2
S1
SSIClk
S3
SSIFss
SSITx
MSB
LSB
8-bit control
SSIRx
0
MSB
LSB
4 to 16 bits output data
Figure 19-6. SSI Timing for SPI Frame Format (FRF=00), with SPH=1
S1
S4
S2
SSIClk
(SPO=0)
S3
SSIClk
(SPO=1)
S6
SSITx
(master)
MSB
S5
SSIRx
(slave)
S7
S8
LSB
S9
MSB
LSB
SSIFss
19.2.7
JTAG and Boundary Scan
Table 19-14. JTAG Characteristics
Parameter No.
Parameter
J1
fTCK
Parameter Name
TCK operational clock frequency
J2
tTCK
TCK operational clock period
J3
tTCK_LOW
TCK clock Low time
400
Min Nom Max Unit
0
-
10 MHz
100
-
-
ns
-
tTCK
-
ns
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Parameter No.
Parameter
J4
tTCK_HIGH
J5
Parameter Name
Min Nom Max Unit
TCK clock High time
-
tTCK
-
ns
tTCK_R
TCK rise time
0
-
10
ns
J6
tTCK_F
TCK fall time
0
-
10
ns
J7
tTMS_SU
TMS setup time to TCK rise
20
-
-
ns
J8
tTMS_HLD
TMS hold time from TCK rise
20
-
-
ns
J9
tTDI_SU
TDI setup time to TCK rise
25
-
-
ns
J10
tTDI_HLD
TDI hold time from TCK rise
25
-
-
ns
J11
TCK fall to Data Valid from High-Z
-
23
35
ns
4-mA drive
15
26
ns
8-mA drive
14
25
ns
18
29
ns
21
35
ns
4-mA drive
14
25
ns
8-mA drive
13
24
ns
8-mA drive with slew rate control
18
28
ns
2-mA drive
t TDO_ZDV
8-mA drive with slew rate control
J12
TCK fall to Data Valid from Data Valid
2-mA drive
t TDO_DV
J13
TCK fall to High-Z from Data Valid
2-mA drive
9
11
ns
4-mA drive
7
9
ns
8-mA drive
6
8
ns
8-mA drive with slew rate control
7
9
ns
t TDO_DVZ
J14
tTRST
J15
tTRST_SU
-
-
TRST assertion time
100
-
-
ns
TRST setup time to TCK rise
10
-
-
ns
Figure 19-7. JTAG Test Clock Input Timing
J2
J3
J4
TCK
J6
J5
October 09, 2007
401
Preliminary
Electrical Characteristics
Figure 19-8. JTAG Test Access Port (TAP) Timing
TCK
J7
TMS
TDI
J8
J7
J8
TMS Input Valid
TMS Input Valid
J9
J9
J10
TDI Input Valid
J10
TDI Input Valid
J11
J12
TDO
J13
TDO Output Valid
TDO Output Valid
Figure 19-9. JTAG TRST Timing
TCK
J14
J15
TRST
19.2.8
General-Purpose I/O
Note:
All GPIOs are 5 V-tolerant.
Table 19-15. GPIO Characteristics
Parameter Parameter Name
tGPIOR
Condition
GPIO Rise Time (from 20% to 80% of VDD)
Min Nom Max Unit
2-mA drive
-
4-mA drive
tGPIOF
19.2.9
17
26
ns
9
13
ns
8-mA drive
6
9
ns
8-mA drive with slew rate control
10
12
ns
17
25
ns
4-mA drive
8
12
ns
8-mA drive
6
10
ns
8-mA drive with slew rate control
11
13
ns
GPIO Fall Time (from 80% to 20% of VDD)
2-mA drive
-
Reset
Table 19-16. Reset Characteristics
Parameter No. Parameter Parameter Name
R1
VTH
Reset threshold
Min Nom Max Unit
-
402
2.0
-
V
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Parameter No. Parameter Parameter Name
Min Nom Max Unit
R2
VBTH
Brown-Out threshold
2.85 2.9 2.95
R3
TPOR
Power-On Reset timeout
R4
TBOR
R5
TIRPOR
R6
TIRBOR
Internal reset timeout after BOR
R7
TIRHWR
Internal reset timeout after hardware reset (RST pin)
-
10
Brown-Out timeout
-
500
-
µs
Internal reset timeout after POR
6
-
11
ms
0
-
1
µs
0
-
1
ms
2.5
-
20
µs
2.5
-
20
µs
Supply voltage (VDD) rise time (0V-3.3V)
-
-
100 ms
Minimum RST pulse width
2
-
a
R8
TIRSWR
Internal reset timeout after software-initiated system
R9
TIRWDR
Internal reset timeout after watchdog reseta
R10
TVDDRISE
R11
TMIN
reset a
-
V
-
ms
µs
a. 20 * t MOSC_per
Figure 19-10. External Reset Timing (RST)
RST
R7
R11
/Reset
(Internal)
Figure 19-11. Power-On Reset Timing
R1
VDD
R3
/POR
(Internal)
R5
/Reset
(Internal)
Figure 19-12. Brown-Out Reset Timing
R2
VDD
R4
/BOR
(Internal)
R6
/Reset
(Internal)
October 09, 2007
403
Preliminary
Electrical Characteristics
Figure 19-13. Software Reset Timing
SW Reset
R8
/Reset
(Internal)
Figure 19-14. Watchdog Reset Timing
WDOG
Reset
(Internal)
R9
/Reset
(Internal)
404
October 09, 2007
Preliminary
LM3S1911 Microcontroller
20
Package Information
Figure 20-1. 100-Pin LQFP Package
Note:
The following notes apply to the package drawing.
1. All dimensions shown in mm.
2. Dimensions shown are nominal with tolerances indicated.
3. Foot length 'L' is measured at gage plane 0.25 mm above seating plane.
October 09, 2007
405
Preliminary
Package Information
Body +2.00 mm Footprint, 1.4 mm package thickness
Symbols
Leads
100L
A
Max.
1.60
A1
0.05 Min./0.15 Max.
A2
±0.05
1.40
D
±0.20
16.00
D1
±0.05
14.00
E
±0.20
16.00
E1
±0.05
14.00
L
±0.15/-0.10
0.60
e
BASIC
0.50
b
±0.05
0.22
θ
===
0˚~7˚
ddd
Max.
0.08
ccc
Max.
0.08
JEDEC Reference Drawing
MS-026
Variation Designator
BED
406
October 09, 2007
Preliminary
LM3S1911 Microcontroller
A
Serial Flash Loader
A.1
Serial Flash Loader
®
The Stellaris serial flash loader is a preprogrammed flash-resident utility 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 SSI0 interfaces. For simplicity, both
the data format and communication protocol are identical for both serial interfaces.
A.2
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.
A.2.1
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
which is calculated as follows:
Max Baud Rate = System Clock Frequency / 16
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 0.35 ms.
A.2.2
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 “Frame
Formats” on page 295 in the SSI chapter for more information on formats for 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
October 09, 2007
407
Preliminary
Serial Flash Loader
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.
A.3
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
format for receiving and sending packets, including the method used to acknowledge successful or
unsuccessful reception of a packet.
A.3.1
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[];
};
A.3.2
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.
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 section that describes the serial
flash loader command, COMMAND_SEND_DATA (see “COMMAND_SEND_DATA
(0x24)” on page 410).
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.
A.3.3
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
408
October 09, 2007
Preliminary
LM3S1911 Microcontroller
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.
A.4
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.
A.4.1
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.
A.4.2
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
A.4.3
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]
Byte[1]
Byte[2]
Byte[3]
Byte[4]
Byte[5]
Byte[6]
Byte[7]
=
=
=
=
=
=
=
=
11
checksum(Bytes[2:10])
COMMAND_DOWNLOAD
Program Address [31:24]
Program Address [23:16]
Program Address [15:8]
Program Address [7:0]
Program Size [31:24]
October 09, 2007
409
Preliminary
Serial Flash Loader
Byte[8] = Program Size [23:16]
Byte[9] = Program Size [15:8]
Byte[10] = Program Size [7:0]
A.4.4
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
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]
A.4.5
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]
A.4.6
=
=
=
=
=
=
=
7
checksum(Bytes[2:6])
COMMAND_RUN
Execute Address[31:24]
Execute Address[23:16]
Execute Address[15:8]
Execute Address[7:0]
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.
410
October 09, 2007
Preliminary
LM3S1911 Microcontroller
Byte[0] = 3
Byte[1] = checksum(Byte[2])
Byte[2] = COMMAND_RESET
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.
October 09, 2007
411
Preliminary
Register Quick Reference
B
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
System Control
Base 0x400F.E000
DID0, type RO, offset 0x000, reset VER
CLASS
MAJOR
MINOR
PBORCTL, type R/W, offset 0x030, reset 0x0000.7FFD
BORIOR
LDOPCTL, type R/W, offset 0x034, reset 0x0000.0000
VADJ
RIS, type RO, offset 0x050, reset 0x0000.0000
PLLLRIS
BORRIS
PLLLIM
BORIM
PLLLMIS
BORMIS
IMC, type R/W, offset 0x054, reset 0x0000.0000
MISC, type R/W1C, offset 0x058, reset 0x0000.0000
RESC, type R/W, offset 0x05C, reset -
LDO
SW
WDT
BOR
POR
EXT
RCC, type R/W, offset 0x060, reset 0x07A0.3AD1
ACG
PWRDN
SYSDIV
USESYSDIV
BYPASS
XTAL
OSCSRC
IOSCDIS MOSCDIS
PLLCFG, type RO, offset 0x064, reset -
OD
F
R
RCC2, type R/W, offset 0x070, reset 0x0780.2800
USERCC2
SYSDIV2
PWRDN2
BYPASS2
OSCSRC2
DSLPCLKCFG, type R/W, offset 0x144, reset 0x0780.0000
DSDIVORIDE
DSOSCSRC
DID1, type RO, offset 0x004, reset VER
FAM
PARTNO
PINCOUNT
TEMP
PKG
ROHS
QUAL
DC0, type RO, offset 0x008, reset 0x00FF.007F
SRAMSZ
FLASHSZ
DC1, type RO, offset 0x010, reset 0x0000.30DF
MINSYSDIV
MPU
HIB
PLL
WDT
SWO
SWD
JTAG
TIMER3
TIMER2
TIMER1
TIMER0
UART2
UART1
UART0
DC2, type RO, offset 0x014, reset 0x030F.5037
COMP1
I2C1
COMP0
I2C0
SSI1
SSI0
DC3, type RO, offset 0x018, reset 0x3F00.0FC0
CCP5
CCP4
CCP3
C1O
CCP2
CCP1
C1PLUS C1MINUS
CCP0
C0O
C0PLUS C0MINUS
412
October 09, 2007
Preliminary
LM3S1911 Microcontroller
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
TIMER2
TIMER1
TIMER0
UART2
UART1
UART0
TIMER2
TIMER1
TIMER0
UART2
UART1
UART0
TIMER2
TIMER1
TIMER0
UART2
UART1
UART0
DC4, type RO, offset 0x01C, reset 0x0000.C0FF
CCP7
CCP6
RCGC0, type R/W, offset 0x100, reset 0x00000040
HIB
WDT
HIB
WDT
HIB
WDT
SCGC0, type R/W, offset 0x110, reset 0x00000040
DCGC0, type R/W, offset 0x120, reset 0x00000040
RCGC1, type R/W, offset 0x104, reset 0x00000000
COMP1
I2C1
COMP0
TIMER3
I2C0
SSI1
SSI0
SSI1
SSI0
SSI1
SSI0
SCGC1, type R/W, offset 0x114, reset 0x00000000
COMP1
I2C1
COMP0
TIMER3
I2C0
DCGC1, type R/W, offset 0x124, reset 0x00000000
COMP1
I2C1
COMP0
TIMER3
I2C0
RCGC2, type R/W, offset 0x108, reset 0x00000000
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
TIMER2
TIMER1
TIMER0
UART2
UART1
UART0
GPIOC
GPIOB
GPIOA
SCGC2, type R/W, offset 0x118, reset 0x00000000
DCGC2, type R/W, offset 0x128, reset 0x00000000
SRCR0, type R/W, offset 0x040, reset 0x00000000
HIB
WDT
SRCR1, type R/W, offset 0x044, reset 0x00000000
COMP1
I2C1
COMP0
TIMER3
I2C0
SSI1
SSI0
GPIOF
GPIOE
SRCR2, type R/W, offset 0x048, reset 0x00000000
GPIOH
GPIOG
GPIOD
Hibernation Module
Base 0x400F.C000
HIBRTCC, type RO, offset 0x000, reset 0x0000.0000
RTCC
RTCC
HIBRTCM0, type R/W, offset 0x004, reset 0xFFFF.FFFF
RTCM0
RTCM0
HIBRTCM1, type R/W, offset 0x008, reset 0xFFFF.FFFF
RTCM1
RTCM1
HIBRTCLD, type R/W, offset 0x00C, reset 0xFFFF.FFFF
RTCLD
RTCLD
October 09, 2007
413
Preliminary
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
HIBREQ
RTCEN
HIBCTL, type R/W, offset 0x010, reset 0x0000.0000
VABORT CLK32EN LOWBATEN PINWEN RTCWEN CLKSEL
HIBIM, type R/W, offset 0x014, reset 0x0000.0000
EXTW
LOWBAT RTCALT1 RTCALT0
EXTW
LOWBAT RTCALT1 RTCALT0
EXTW
LOWBAT RTCALT1 RTCALT0
EXTW
LOWBAT RTCALT1 RTCALT0
HIBRIS, type RO, offset 0x018, reset 0x0000.0000
HIBMIS, type RO, offset 0x01C, reset 0x0000.0000
HIBIC, type R/W1C, offset 0x020, reset 0x0000.0000
HIBRTCT, type R/W, offset 0x024, reset 0x0000.7FFF
TRIM
HIBDATA, type R/W, offset 0x030-0x12C, reset 0x0000.0000
RTD
RTD
Internal Memory
Flash Control Offset
Base 0x400F.D000
FMA, type R/W, offset 0x000, reset 0x0000.0000
OFFSET
OFFSET
FMD, type R/W, offset 0x004, reset 0x0000.0000
DATA
DATA
FMC, type R/W, offset 0x008, reset 0x0000.0000
WRKEY
COMT
MERASE
ERASE
WRITE
PRIS
ARIS
PMASK
AMASK
PMISC
AMISC
FCRIS, type RO, offset 0x00C, reset 0x0000.0000
FCIM, type R/W, offset 0x010, reset 0x0000.0000
FCMISC, type R/W1C, offset 0x014, reset 0x0000.0000
Internal Memory
System Control Offset
Base 0x400F.E000
USECRL, type R/W, offset 0x140, reset 0x31
USEC
FMPRE0, type R/W, offset 0x130 and 0x200, reset 0xFFFF.FFFF
READ_ENABLE
READ_ENABLE
414
October 09, 2007
Preliminary
LM3S1911 Microcontroller
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DBG1
DBG0
FMPPE0, type R/W, offset 0x134 and 0x400, reset 0xFFFF.FFFF
PROG_ENABLE
PROG_ENABLE
USER_DBG, type R/W, offset 0x1D0, reset 0xFFFF.FFFE
NW
DATA
DATA
USER_REG0, type R/W, offset 0x1E0, reset 0xFFFF.FFFF
NW
DATA
DATA
USER_REG1, type R/W, offset 0x1E4, reset 0xFFFF.FFFF
NW
DATA
DATA
FMPRE1, type R/W, offset 0x204, reset 0xFFFF.FFFF
READ_ENABLE
READ_ENABLE
FMPRE2, type R/W, offset 0x208, reset 0xFFFF.FFFF
READ_ENABLE
READ_ENABLE
FMPRE3, type R/W, offset 0x20C, reset 0xFFFF.FFFF
READ_ENABLE
READ_ENABLE
FMPPE1, type R/W, offset 0x404, reset 0xFFFF.FFFF
PROG_ENABLE
PROG_ENABLE
FMPPE2, type R/W, offset 0x408, reset 0xFFFF.FFFF
PROG_ENABLE
PROG_ENABLE
FMPPE3, type R/W, offset 0x40C, reset 0xFFFF.FFFF
PROG_ENABLE
PROG_ENABLE
General-Purpose Input/Outputs (GPIOs)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
GPIO Port H base: 0x4002.7000
GPIODATA, type R/W, offset 0x000, reset 0x0000.0000
DATA
GPIODIR, type R/W, offset 0x400, reset 0x0000.0000
DIR
GPIOIS, type R/W, offset 0x404, reset 0x0000.0000
IS
GPIOIBE, type R/W, offset 0x408, reset 0x0000.0000
IBE
GPIOIEV, type R/W, offset 0x40C, reset 0x0000.0000
IEV
October 09, 2007
415
Preliminary
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GPIOIM, type R/W, offset 0x410, reset 0x0000.0000
IME
GPIORIS, type RO, offset 0x414, reset 0x0000.0000
RIS
GPIOMIS, type RO, offset 0x418, reset 0x0000.0000
MIS
GPIOICR, type W1C, offset 0x41C, reset 0x0000.0000
IC
GPIOAFSEL, type R/W, offset 0x420, reset -
AFSEL
GPIODR2R, type R/W, offset 0x500, reset 0x0000.00FF
DRV2
GPIODR4R, type R/W, offset 0x504, reset 0x0000.0000
DRV4
GPIODR8R, type R/W, offset 0x508, reset 0x0000.0000
DRV8
GPIOODR, type R/W, offset 0x50C, reset 0x0000.0000
ODE
GPIOPUR, type R/W, offset 0x510, reset -
PUE
GPIOPDR, type R/W, offset 0x514, reset 0x0000.0000
PDE
GPIOSLR, type R/W, offset 0x518, reset 0x0000.0000
SRL
GPIODEN, type R/W, offset 0x51C, reset -
DEN
GPIOLOCK, type R/W, offset 0x520, reset 0x0000.0001
LOCK
LOCK
GPIOCR, type -, offset 0x524, reset -
CR
GPIOPeriphID4, type RO, offset 0xFD0, reset 0x0000.0000
PID4
GPIOPeriphID5, type RO, offset 0xFD4, reset 0x0000.0000
PID5
416
October 09, 2007
Preliminary
LM3S1911 Microcontroller
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GPIOPeriphID6, type RO, offset 0xFD8, reset 0x0000.0000
PID6
GPIOPeriphID7, type RO, offset 0xFDC, reset 0x0000.0000
PID7
GPIOPeriphID0, type RO, offset 0xFE0, reset 0x0000.0061
PID0
GPIOPeriphID1, type RO, offset 0xFE4, reset 0x0000.0000
PID1
GPIOPeriphID2, type RO, offset 0xFE8, reset 0x0000.0018
PID2
GPIOPeriphID3, type RO, offset 0xFEC, reset 0x0000.0001
PID3
GPIOPCellID0, type RO, offset 0xFF0, reset 0x0000.000D
CID0
GPIOPCellID1, type RO, offset 0xFF4, reset 0x0000.00F0
CID1
GPIOPCellID2, type RO, offset 0xFF8, reset 0x0000.0005
CID2
GPIOPCellID3, type RO, offset 0xFFC, reset 0x0000.00B1
CID3
General-Purpose Timers
Timer0 base: 0x4003.0000
Timer1 base: 0x4003.1000
Timer2 base: 0x4003.2000
Timer3 base: 0x4003.3000
GPTMCFG, type R/W, offset 0x000, reset 0x0000.0000
GPTMCFG
GPTMTAMR, type R/W, offset 0x004, reset 0x0000.0000
TAAMS
TACMR
TAMR
TBAMS
TBCMR
TBMR
GPTMTBMR, type R/W, offset 0x008, reset 0x0000.0000
GPTMCTL, type R/W, offset 0x00C, reset 0x0000.0000
TBPWML
TBOTE
TBEVENT
TBSTALL
TBEN
TAPWML
TAOTE
RTCEN
TAEVENT
CBEIM
CBMIM
TBTOIM
RTCIM
CBERIS
CBMRIS TBTORIS
RTCRIS
TASTALL
TAEN
CAEIM
CAMIM
TATOIM
CAERIS
CAMRIS
TATORIS
GPTMIMR, type R/W, offset 0x018, reset 0x0000.0000
GPTMRIS, type RO, offset 0x01C, reset 0x0000.0000
October 09, 2007
417
Preliminary
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTCMIS
CAEMIS
GPTMMIS, type RO, offset 0x020, reset 0x0000.0000
CBEMIS
CBMMIS TBTOMIS
CAMMIS TATOMIS
GPTMICR, type W1C, offset 0x024, reset 0x0000.0000
CBECINT CBMCINT TBTOCINT
RTCCINT CAECINT CAMCINT TATOCINT
GPTMTAILR, type R/W, offset 0x028, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode)
TAILRH
TAILRL
GPTMTBILR, type R/W, offset 0x02C, reset 0x0000.FFFF
TBILRL
GPTMTAMATCHR, type R/W, offset 0x030, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode)
TAMRH
TAMRL
GPTMTBMATCHR, type R/W, offset 0x034, reset 0x0000.FFFF
TBMRL
GPTMTAPR, type R/W, offset 0x038, reset 0x0000.0000
TAPSR
GPTMTBPR, type R/W, offset 0x03C, reset 0x0000.0000
TBPSR
GPTMTAPMR, type R/W, offset 0x040, reset 0x0000.0000
TAPSMR
GPTMTBPMR, type R/W, offset 0x044, reset 0x0000.0000
TBPSMR
GPTMTAR, type RO, offset 0x048, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode)
TARH
TARL
GPTMTBR, type RO, offset 0x04C, reset 0x0000.FFFF
TBRL
Watchdog Timer
Base 0x4000.0000
WDTLOAD, type R/W, offset 0x000, reset 0xFFFF.FFFF
WDTLoad
WDTLoad
WDTVALUE, type RO, offset 0x004, reset 0xFFFF.FFFF
WDTValue
WDTValue
WDTCTL, type R/W, offset 0x008, reset 0x0000.0000
RESEN
INTEN
WDTICR, type WO, offset 0x00C, reset WDTIntClr
WDTIntClr
WDTRIS, type RO, offset 0x010, reset 0x0000.0000
WDTRIS
418
October 09, 2007
Preliminary
LM3S1911 Microcontroller
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WDTMIS, type RO, offset 0x014, reset 0x0000.0000
WDTMIS
WDTTEST, type R/W, offset 0x418, reset 0x0000.0000
STALL
WDTLOCK, type R/W, offset 0xC00, reset 0x0000.0000
WDTLock
WDTLock
WDTPeriphID4, type RO, offset 0xFD0, reset 0x0000.0000
PID4
WDTPeriphID5, type RO, offset 0xFD4, reset 0x0000.0000
PID5
WDTPeriphID6, type RO, offset 0xFD8, reset 0x0000.0000
PID6
WDTPeriphID7, type RO, offset 0xFDC, reset 0x0000.0000
PID7
WDTPeriphID0, type RO, offset 0xFE0, reset 0x0000.0005
PID0
WDTPeriphID1, type RO, offset 0xFE4, reset 0x0000.0018
PID1
WDTPeriphID2, type RO, offset 0xFE8, reset 0x0000.0018
PID2
WDTPeriphID3, type RO, offset 0xFEC, reset 0x0000.0001
PID3
WDTPCellID0, type RO, offset 0xFF0, reset 0x0000.000D
CID0
WDTPCellID1, type RO, offset 0xFF4, reset 0x0000.00F0
CID1
WDTPCellID2, type RO, offset 0xFF8, reset 0x0000.0005
CID2
WDTPCellID3, type RO, offset 0xFFC, reset 0x0000.00B1
CID3
Universal Asynchronous Receivers/Transmitters (UARTs)
UART0 base: 0x4000.C000
UART1 base: 0x4000.D000
UART2 base: 0x4000.E000
UARTDR, type R/W, offset 0x000, reset 0x0000.0000
OE
BE
PE
FE
October 09, 2007
DATA
419
Preliminary
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OE
BE
PE
FE
EPS
PEN
BRK
SIRLP
SIREN
UARTEN
UARTRSR/UARTECR, type RO, offset 0x004, reset 0x0000.0000
UARTRSR/UARTECR, type WO, offset 0x004, reset 0x0000.0000
DATA
UARTFR, type RO, offset 0x018, reset 0x0000.0090
TXFE
RXFF
TXFF
RXFE
BUSY
UARTILPR, type R/W, offset 0x020, reset 0x0000.0000
ILPDVSR
UARTIBRD, type R/W, offset 0x024, reset 0x0000.0000
DIVINT
UARTFBRD, type R/W, offset 0x028, reset 0x0000.0000
DIVFRAC
UARTLCRH, type R/W, offset 0x02C, reset 0x0000.0000
SPS
WLEN
FEN
STP2
UARTCTL, type R/W, offset 0x030, reset 0x0000.0300
RXE
TXE
LBE
UARTIFLS, type R/W, offset 0x034, reset 0x0000.0012
RXIFLSEL
TXIFLSEL
UARTIM, type R/W, offset 0x038, reset 0x0000.0000
OEIM
BEIM
PEIM
FEIM
RTIM
TXIM
RXIM
OERIS
BERIS
PERIS
FERIS
RTRIS
TXRIS
RXRIS
OEMIS
BEMIS
PEMIS
FEMIS
RTMIS
TXMIS
RXMIS
OEIC
BEIC
PEIC
FEIC
RTIC
TXIC
RXIC
UARTRIS, type RO, offset 0x03C, reset 0x0000.000F
UARTMIS, type RO, offset 0x040, reset 0x0000.0000
UARTICR, type W1C, offset 0x044, reset 0x0000.0000
UARTPeriphID4, type RO, offset 0xFD0, reset 0x0000.0000
PID4
UARTPeriphID5, type RO, offset 0xFD4, reset 0x0000.0000
PID5
UARTPeriphID6, type RO, offset 0xFD8, reset 0x0000.0000
PID6
UARTPeriphID7, type RO, offset 0xFDC, reset 0x0000.0000
PID7
420
October 09, 2007
Preliminary
LM3S1911 Microcontroller
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
UARTPeriphID0, type RO, offset 0xFE0, reset 0x0000.0011
PID0
UARTPeriphID1, type RO, offset 0xFE4, reset 0x0000.0000
PID1
UARTPeriphID2, type RO, offset 0xFE8, reset 0x0000.0018
PID2
UARTPeriphID3, type RO, offset 0xFEC, reset 0x0000.0001
PID3
UARTPCellID0, type RO, offset 0xFF0, reset 0x0000.000D
CID0
UARTPCellID1, type RO, offset 0xFF4, reset 0x0000.00F0
CID1
UARTPCellID2, type RO, offset 0xFF8, reset 0x0000.0005
CID2
UARTPCellID3, type RO, offset 0xFFC, reset 0x0000.00B1
CID3
Synchronous Serial Interface (SSI)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
SSICR0, type R/W, offset 0x000, reset 0x0000.0000
SCR
SPH
SPO
FRF
DSS
SSICR1, type R/W, offset 0x004, reset 0x0000.0000
SOD
MS
SSE
LBM
RFF
RNE
TNF
TFE
TXIM
RXIM
RTIM
RORIM
TXRIS
RXRIS
RTRIS
RORRIS
TXMIS
RXMIS
RTMIS
RORMIS
SSIDR, type R/W, offset 0x008, reset 0x0000.0000
DATA
SSISR, type RO, offset 0x00C, reset 0x0000.0003
BSY
SSICPSR, type R/W, offset 0x010, reset 0x0000.0000
CPSDVSR
SSIIM, type R/W, offset 0x014, reset 0x0000.0000
SSIRIS, type RO, offset 0x018, reset 0x0000.0008
SSIMIS, type RO, offset 0x01C, reset 0x0000.0000
October 09, 2007
421
Preliminary
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTIC
RORIC
SSIICR, type W1C, offset 0x020, reset 0x0000.0000
SSIPeriphID4, type RO, offset 0xFD0, reset 0x0000.0000
PID4
SSIPeriphID5, type RO, offset 0xFD4, reset 0x0000.0000
PID5
SSIPeriphID6, type RO, offset 0xFD8, reset 0x0000.0000
PID6
SSIPeriphID7, type RO, offset 0xFDC, reset 0x0000.0000
PID7
SSIPeriphID0, type RO, offset 0xFE0, reset 0x0000.0022
PID0
SSIPeriphID1, type RO, offset 0xFE4, reset 0x0000.0000
PID1
SSIPeriphID2, type RO, offset 0xFE8, reset 0x0000.0018
PID2
SSIPeriphID3, type RO, offset 0xFEC, reset 0x0000.0001
PID3
SSIPCellID0, type RO, offset 0xFF0, reset 0x0000.000D
CID0
SSIPCellID1, type RO, offset 0xFF4, reset 0x0000.00F0
CID1
SSIPCellID2, type RO, offset 0xFF8, reset 0x0000.0005
CID2
SSIPCellID3, type RO, offset 0xFFC, reset 0x0000.00B1
CID3
Inter-Integrated Circuit
(I2C)
Interface
I2C Master
I2C Master 0 base: 0x4002.0000
I2C Master 1 base: 0x4002.1000
I2CMSA, type R/W, offset 0x000, reset 0x0000.0000
SA
R/S
I2CMCS, type RO, offset 0x004, reset 0x0000.0000
BUSBSY
IDLE
ARBLST
DATACK
ADRACK
ERROR
BUSY
ACK
STOP
START
RUN
I2CMCS, type WO, offset 0x004, reset 0x0000.0000
422
October 09, 2007
Preliminary
LM3S1911 Microcontroller
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
I2CMDR, type R/W, offset 0x008, reset 0x0000.0000
DATA
I2CMTPR, type R/W, offset 0x00C, reset 0x0000.0001
TPR
I2CMIMR, type R/W, offset 0x010, reset 0x0000.0000
IM
I2CMRIS, type RO, offset 0x014, reset 0x0000.0000
RIS
I2CMMIS, type RO, offset 0x018, reset 0x0000.0000
MIS
I2CMICR, type WO, offset 0x01C, reset 0x0000.0000
IC
I2CMCR, type R/W, offset 0x020, reset 0x0000.0000
SFE
Inter-Integrated Circuit
(I2C)
MFE
LPBK
Interface
I2C Slave
I2C Slave 0 base: 0x4002.0800
I2C Slave 1 base: 0x4002.1800
I2CSOAR, type R/W, offset 0x000, reset 0x0000.0000
OAR
I2CSCSR, type RO, offset 0x004, reset 0x0000.0000
FBR
TREQ
RREQ
I2CSCSR, type WO, offset 0x004, reset 0x0000.0000
DA
I2CSDR, type R/W, offset 0x008, reset 0x0000.0000
DATA
I2CSIMR, type R/W, offset 0x00C, reset 0x0000.0000
IM
I2CSRIS, type RO, offset 0x010, reset 0x0000.0000
RIS
I2CSMIS, type RO, offset 0x014, reset 0x0000.0000
MIS
I2CSICR, type WO, offset 0x018, reset 0x0000.0000
IC
Analog Comparators
October 09, 2007
423
Preliminary
Register Quick Reference
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IN1
IN0
IN1
IN0
IN1
IN0
Base 0x4003.C000
ACMIS, type R/W1C, offset 0x00, reset 0x0000.0000
ACRIS, type RO, offset 0x04, reset 0x0000.0000
ACINTEN, type R/W, offset 0x08, reset 0x0000.0000
ACREFCTL, type R/W, offset 0x10, reset 0x0000.0000
EN
RNG
VREF
ACSTAT0, type RO, offset 0x20, reset 0x0000.0000
OVAL
ACSTAT1, type RO, offset 0x40, reset 0x0000.0000
OVAL
ACCTL0, type RO, offset 0x24, reset 0x0000.0000
ASRCP
ISLVAL
ISEN
CINV
ASRCP
ISLVAL
ISEN
CINV
ACCTL1, type RO, offset 0x44, reset 0x0000.0000
424
October 09, 2007
Preliminary
LM3S1911 Microcontroller
C
Ordering and Contact Information
C.1
Ordering Information
LM3Snnnn–gppss–rrm
Part Number
Shipping Medium
T = Tape-and-reel
Omitted = Default shipping (tray or tube)
Temperature
I = -40 C to 85 C
Revision
Omitted = Default to current shipping
revision
A0 = First all-layer mask
A1 = Metal layers update to A0
A2 = Metal layers update to A1
B0 = Second all-layer mask revision
Package
RN = 28-pin SOIC
QN = 48-pin LQFP
QC = 100-pin LQFP
Speed
20 = 20 MHz
25 = 25 MHz
50 = 50 MHz
Table C-1. Part Ordering Information
Orderable Part Number Description
C.2
®
LM3S1911-IQC50
Stellaris LM3S1911 Microcontroller
LM3S1911-IQC50(T)
Stellaris LM3S1911 Microcontroller
®
Kits
®
The Luminary Micro Stellaris Family provides the hardware and software tools that engineers need
to begin development quickly.
■ Reference Design Kits accelerate product development by providing ready-to-run hardware, and
comprehensive documentation including hardware design files:
http://www.luminarymicro.com/products/reference_design_kits/
®
■ Evaluation Kits provide a low-cost and effective means of evaluating Stellaris microcontrollers
before purchase:
http://www.luminarymicro.com/products/evaluation_kits/
■ Development Kits provide you with all the tools you need to develop and prototype embedded
applications right out of the box:
http://www.luminarymicro.com/products/boards.html
See the Luminary Micro website for the latest tools available or ask your Luminary Micro distributor.
C.3
Company Information
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
October 09, 2007
425
Preliminary
Ordering and Contact Information
Stellaris® 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
[email protected]
C.4
Support Information
For support on Luminary Micro products, contact:
[email protected] +1-512-279-8800, ext. 3
426
October 09, 2007
Preliminary