begriffs open source - cmsis-freertos/blob - Demo/CORTEX_LM3S102

1 /*

4

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25 ***************************************************************************

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67 1 tab == 4 spaces!

68 */

69

70 /*

71 * This demo application creates six co-routines and two tasks (three including

72 * the idle task). The co-routines execute as part of the idle task hook.

73 *

74 * Five of the created co-routines are the standard 'co-routine flash'

75 * co-routines contained within the Demo/Common/Minimal/crflash.c file and

76 * documented on the FreeRTOS.org WEB site.

77 *

78 * The 'LCD Task' rotates a string on the LCD, delaying between each character

79 * as necessitated by the slow interface, and delaying between each string just

80 * long enough to enable the text to be read.

81 *

82 * The sixth co-routine and final task control the transmission and reception

83 * of a string to UART 0. The co-routine periodically sends the first

84 * character of the string to the UART, with the UART's TxEnd interrupt being

85 * used to transmit the remaining characters. The UART's RxEnd interrupt

86 * receives the characters and places them on a queue to be processed by the

87 * 'COMs Rx' task. An error is latched should an unexpected character be

88 * received, or any character be received out of sequence.

89 *

90 * A loopback connector is required to ensure that each character transmitted

91 * on the UART is also received on the same UART. For test purposes the UART

92 * FIFO's are not utalised in order to maximise the interrupt overhead. Also

93 * a pseudo random interval is used between the start of each transmission in

94 * order that the resultant interrupts are more randomly distributed and

95 * therefore more likely to highlight any problems.

96 *

97 * The flash co-routines control LED's zero to four. LED five is toggled each

98 * time the string is transmitted on the UART. LED six is toggled each time

99 * the string is CORRECTLY received on the UART. LED seven is latched on should

100 * an error be detected in any task or co-routine.

101 *

102 * In addition the idle task makes repetative calls to

103 * prvSetAndCheckRegisters(). This simply loads the general purpose registers

104 * with a known value, then checks each register to ensure the held value is

105 * still correct. As a low priority task this checking routine is likely to

106 * get repeatedly swapped in and out. A register being found to contain an

107 * incorrect value is therefore indicative of an error in the task switching

108 * mechansim.

109 *

110 */

111

112 /* Scheduler include files. */

113 #include "FreeRTOS.h"

114 #include "task.h"

115 #include "queue.h"

116 #include "croutine.h"

117

118 /* Demo application include files. */

119 #include "partest.h"

120 #include "crflash.h"

121

122 /* Library include files. */

123 #include "DriverLib.h"

124

125 /* The time to delay between writing each character to the LCD. */

126 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_PERIOD_MS )

127

128 /* The time to delay between writing each string to the LCD. */

129 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_PERIOD_MS )

130

131 /* The number of flash co-routines to create. */

132 #define mainNUM_FLASH_CO_ROUTINES ( 5 )

133

134 /* The length of the queue used to pass received characters to the Comms Rx

135 task. */

136 #define mainRX_QUEUE_LEN ( 5 )

137

138 /* The priority of the co-routine used to initiate the transmission of the

139 string on UART 0. */

140 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )

141

142 /* Only one co-routine is created so its index is not important. */

143 #define mainTX_CO_ROUTINE_INDEX ( 0 )

144

145 /* The time between transmissions of the string on UART 0. This is pseudo

146 random in order to generate a bit or randomness to when the interrupts occur.*/

147 #define mainMIN_TX_DELAY ( 40 / portTICK_PERIOD_MS )

148 #define mainMAX_TX_DELAY ( ( TickType_t ) 0x7f )

149 #define mainOFFSET_TIME ( ( TickType_t ) 3 )

150

151 /* The time the Comms Rx task should wait to receive a character. This should

152 be slightly longer than the time between transmissions. If we do not receive

153 a character after this time then there must be an error in the transmission or

154 the timing of the transmission. */

155 #define mainCOMMS_RX_DELAY ( mainMAX_TX_DELAY + 20 )

156

157 /* The task priorites. */

158 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY )

159 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )

160

161 /* The LED's toggled by the various tasks. */

162 #define mainCOMMS_FAIL_LED ( 7 )

163 #define mainCOMMS_RX_LED ( 6 )

164 #define mainCOMMS_TX_LED ( 5 )

165

166 /* The baud rate used by the UART comms tasks/co-routine. */

167 #define mainBAUD_RATE ( 57600 )

168

169 /* FIFO setting for the UART. The FIFO is not used to create a better test. */

170 #define mainFIFO_SET ( 0x10 )

171

172 /* The string that is transmitted on the UART contains sequentially the

173 characters from mainFIRST_TX_CHAR to mainLAST_TX_CHAR. */

174 #define mainFIRST_TX_CHAR '0'

175 #define mainLAST_TX_CHAR 'z'

176

177 /* Just used to walk through the program memory in order that some random data

178 can be generated. */

179 #define mainTOTAL_PROGRAM_MEMORY ( ( unsigned long * ) ( 8 * 1024 ) )

180 #define mainFIRST_PROGRAM_BYTES ( ( unsigned long * ) 4 )

181

182 /* The error routine that is called if the driver library encounters an error. */

183 #ifdef DEBUG

184 void

185 __error__(char *pcFilename, unsigned long ulLine)

186 {

187 }

188 #endif

189

190 /*-----------------------------------------------------------*/

191

192 /*

193 * The task that rotates text on the LCD.

194 */

195 static void vLCDTask( void * pvParameters );

196

197 /*

198 * The task that receives the characters from UART 0.

199 */

200 static void vCommsRxTask( void * pvParameters );

201

202 /*

203 * The co-routine that periodically initiates the transmission of the string on

204 * the UART.

205 */

206 static void vSerialTxCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex );

207

208 /*

209 * Writes a string the the LCD.

210 */

211 static void prvWriteString( const char *pcString );

212

213 /*

214 * Initialisation routine for the UART.

215 */

216 static void vSerialInit( void );

217

218 /*

219 * Thread safe write to the PDC.

220 */

221 static void prvPDCWrite( char cAddress, char cData );

222

223 /*

224 * Function to simply set a known value into the general purpose registers

225 * then read them back to ensure they remain set correctly. An incorrect value

226 * being indicative of an error in the task switching mechanism.

227 */

228 void prvSetAndCheckRegisters( void );

229

230 /*

231 * Latch the LED that indicates that an error has occurred.

232 */

233 void vSetErrorLED( void );

234

235 /*

236 * Sets up the PLL and ports used by the demo.

237 */

238 static void prvSetupHardware( void );

239

240 /*-----------------------------------------------------------*/

241

242 /* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines

243 defined within this file. */

244 unsigned portBASE_TYPE uxErrorStatus = pdPASS;

245

246 /* The next character to transmit. */

247 static char cNextChar;

248

249 /* The queue used to transmit characters from the interrupt to the Comms Rx

250 task. */

251 static QueueHandle_t xCommsQueue;

252

253 /*-----------------------------------------------------------*/

254

255 void Main( void )

256 {

257 /* Create the queue used to communicate between the UART ISR and the Comms

258 Rx task. */

259 xCommsQueue = xQueueCreate( mainRX_QUEUE_LEN, sizeof( char ) );

260

261 /* Setup the ports used by the demo and the clock. */

262 prvSetupHardware();

263

264 /* Create the co-routines that flash the LED's. */

265 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );

266

267 /* Create the co-routine that initiates the transmission of characters

268 on the UART. */

269 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );

270

271 /* Create the LCD and Comms Rx tasks. */

272 xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, mainLCD_TASK_PRIORITY, NULL );

273 xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );

274

275 /* Start the scheduler running the tasks and co-routines just created. */

276 vTaskStartScheduler();

277

278 /* Should not get here unless we did not have enough memory to start the

279 scheduler. */

280 for( ;; );

281 }

282 /*-----------------------------------------------------------*/

283

284 static void prvSetupHardware( void )

285 {

286 /* Setup the PLL. */

287 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );

288

289 /* Initialise the hardware used to talk to the LCD, LED's and UART. */

290 PDCInit();

291 vParTestInitialise();

292 vSerialInit();

293 }

294 /*-----------------------------------------------------------*/

295

296 void vApplicationIdleHook( void )

297 {

298 /* The co-routines are executed in the idle task using the idle task

299 hook. */

300 for( ;; )

301 {

302 /* Schedule the co-routines. */

303 vCoRoutineSchedule();

304

305 /* Run the register check function between each co-routine. */

306 prvSetAndCheckRegisters();

307 }

308 }

309 /*-----------------------------------------------------------*/

310

311 static void prvWriteString( const char *pcString )

312 {

313 /* Write pcString to the LED, pausing between each character. */

314 prvPDCWrite(PDC_LCD_CSR, LCD_CLEAR);

315 while( *pcString )

316 {

317 vTaskDelay( mainCHAR_WRITE_DELAY );

318 prvPDCWrite( PDC_LCD_RAM, *pcString );

319 pcString++;

320 }

321 }

322 /*-----------------------------------------------------------*/

323

324 void vLCDTask( void * pvParameters )

325 {

326 unsigned portBASE_TYPE uxIndex;

327 const unsigned char ucCFGData[] = {

328 0x30, /* Set data bus to 8-bits. */

329 0x30,

330 0x30,

331 0x3C, /* Number of lines/font. */

332 0x08, /* Display off. */

333 0x01, /* Display clear. */

334 0x06, /* Entry mode [cursor dir][shift]. */

335 0x0C /* Display on [display on][curson on][blinking on]. */

336 };

337

338 /* The strings that are written to the LCD. */

339 const char *pcStringsToDisplay[] = {

340 "Stellaris",

341 "Demo",

342 "One",

343 "www.FreeRTOS.org",

344 ""

345 };

346

347 /* Configure the LCD. */

348 uxIndex = 0;

349 while( uxIndex < sizeof( ucCFGData ) )

350 {

351 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );

352 uxIndex++;

353 vTaskDelay( mainCHAR_WRITE_DELAY );

354 }

355

356 /* Turn the LCD Backlight on. */

357 prvPDCWrite( PDC_CSR, 0x01 );

358

359 /* Clear display. */

360 vTaskDelay( mainCHAR_WRITE_DELAY );

361 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );

362

363 uxIndex = 0;

364 for( ;; )

365 {

366 /* Display the string on the LCD. */

367 prvWriteString( pcStringsToDisplay[ uxIndex ] );

368

369 /* Move on to the next string - wrapping if necessary. */

370 uxIndex++;

371 if( *( pcStringsToDisplay[ uxIndex ] ) == 0x00 )

372 {

373 uxIndex = 0;

374 /* Longer pause on the last string to be sent. */

375 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );

376 }

377

378 /* Wait until it is time to move onto the next string. */

379 vTaskDelay( mainSTRING_WRITE_DELAY );

380 }

381 }

382 /*-----------------------------------------------------------*/

383

384 static void vCommsRxTask( void * pvParameters )

385 {

386 static char cRxedChar, cExpectedChar;

387

388 /* Set the char we expect to receive to the start of the string. */

389 cExpectedChar = mainFIRST_TX_CHAR;

390

391 for( ;; )

392 {

393 /* Wait for a character to be received. */

394 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, mainCOMMS_RX_DELAY );

395

396 /* Was the character recived (if any) the expected character. */

397 if( cRxedChar != cExpectedChar )

398 {

399 /* Got an unexpected character. This can sometimes occur when

400 reseting the system using the debugger leaving characters already

401 in the UART regsters. */

402 uxErrorStatus = pdFAIL;

403

404 /* Resync by waiting for the end of the current string. */

405 while( cRxedChar != mainLAST_TX_CHAR )

406 {

407 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );

408 }

409

410 /* The next expected character is the start of the string again. */

411 cExpectedChar = mainFIRST_TX_CHAR;

412 }

413 else

414 {

415 if( cExpectedChar == mainLAST_TX_CHAR )

416 {

417 /* We have reached the end of the string - we now expect to

418 receive the first character in the string again. The LED is

419 toggled to indicate that the entire string was received without

420 error. */

421 vParTestToggleLED( mainCOMMS_RX_LED );

422 cExpectedChar = mainFIRST_TX_CHAR;

423 }

424 else

425 {

426 /* We got the expected character, we now expect to receive the

427 next character in the string. */

428 cExpectedChar++;

429 }

430 }

431 }

432 }

433 /*-----------------------------------------------------------*/

434

435 static void vSerialTxCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex )

436 {

437 TickType_t xDelayPeriod;

438 static unsigned long *pulRandomBytes = mainFIRST_PROGRAM_BYTES;

439

440 /* Co-routine MUST start with a call to crSTART. */

441 crSTART( xHandle );

442

443 for(;;)

444 {

445 /* Was the previously transmitted string received correctly? */

446 if( uxErrorStatus != pdPASS )

447 {

448 /* An error was encountered so set the error LED. */

449 vSetErrorLED();

450 }

451

452 /* The next character to Tx is the first in the string. */

453 cNextChar = mainFIRST_TX_CHAR;

454

455 UARTIntDisable( UART0_BASE, UART_INT_TX );

456 {

457 /* Send the first character. */

458 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )

459 {

460 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;

461 }

462

463 /* Move the variable to the char to Tx on so the ISR transmits

464 the next character in the string once this one has completed. */

465 cNextChar++;

466 }

467 UARTIntEnable(UART0_BASE, UART_INT_TX);

468

469 /* Toggle the LED to show a new string is being transmitted. */

470 vParTestToggleLED( mainCOMMS_TX_LED );

471

472 /* Delay before we start the string off again. A pseudo-random delay

473 is used as this will provide a better test. */

474 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );

475

476 pulRandomBytes++;

477 if( pulRandomBytes > mainTOTAL_PROGRAM_MEMORY )

478 {

479 pulRandomBytes = mainFIRST_PROGRAM_BYTES;

480 }

481

482 /* Make sure we don't wait too long... */

483 xDelayPeriod &= mainMAX_TX_DELAY;

484

485 /* ...but we do want to wait. */

486 if( xDelayPeriod < mainMIN_TX_DELAY )

487 {

488 xDelayPeriod = mainMIN_TX_DELAY;

489 }

490

491 /* Block for the random(ish) time. */

492 crDELAY( xHandle, xDelayPeriod );

493 }

494

495 /* Co-routine MUST end with a call to crEND. */

496 crEND();

497 }

498 /*-----------------------------------------------------------*/

499

500 static void vSerialInit( void )

501 {

502 /* Enable the UART. GPIOA has already been initialised. */

503 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

504

505 /* Set GPIO A0 and A1 as peripheral function. They are used to output the

506 UART signals. */

507 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );

508

509 /* Configure the UART for 8-N-1 operation. */

510 UARTConfigSet( UART0_BASE, mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );

511

512 /* We dont want to use the fifo. This is for test purposes to generate

513 as many interrupts as possible. */

514 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;

515

516 /* Enable both Rx and Tx interrupts. */

517 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );

518 IntEnable( INT_UART0 );

519 }

520 /*-----------------------------------------------------------*/

521

522 void vUART_ISR(void)

523 {

524 unsigned long ulStatus;

525 char cRxedChar;

526 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

527

528 /* What caused the interrupt. */

529 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );

530

531 /* Clear the interrupt. */

532 UARTIntClear( UART0_BASE, ulStatus );

533

534 /* Was an Rx interrpt pending? */

535 if( ulStatus & UART_INT_RX )

536 {

537 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )

538 {

539 /* Get the char from the buffer and post it onto the queue of

540 Rxed chars. Posting the character should wake the task that is

541 blocked on the queue waiting for characters. */

542 cRxedChar = ( char ) HWREG( UART0_BASE + UART_O_DR );

543 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );

544 }

545 }

546

547 /* Was a Tx interrupt pending? */

548 if( ulStatus & UART_INT_TX )

549 {

550 /* Send the next character in the string. We are not using the FIFO. */

551 if( cNextChar <= mainLAST_TX_CHAR )

552 {

553 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )

554 {

555 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;

556 }

557 cNextChar++;

558 }

559 }

560

561 /* If a task was woken by the character being received then we force

562 a context switch to occur in case the task is of higher priority than

563 the currently executing task (i.e. the task that this interrupt

564 interrupted.) */

565 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );

566 }

567 /*-----------------------------------------------------------*/

568

569 static void prvPDCWrite( char cAddress, char cData )

570 {

571 vTaskSuspendAll();

572 {

573 PDCWrite( cAddress, cData );

574 }

575 xTaskResumeAll();

576 }

577 /*-----------------------------------------------------------*/

578

579 void vSetErrorLED( void )

580 {

581 vParTestSetLED( mainCOMMS_FAIL_LED, pdTRUE );

582 }

583 /*-----------------------------------------------------------*/

584

585 void prvSetAndCheckRegisters( void )

586 {

587 /* Fill the general purpose registers with known values. */

588 __asm volatile( " mov r11, #10\n"

589 " add r0, r11, #1\n"

590 " add r1, r11, #2\n"

591 " add r2, r11, #3\n"

592 " add r3, r11, #4\n"

593 " add r4, r11, #5\n"

594 " add r5, r11, #6\n"

595 " add r6, r11, #7\n"

596 " add r7, r11, #8\n"

597 " add r8, r11, #9\n"

598 " add r9, r11, #10\n"

599 " add r10, r11, #11\n"

600 " add r12, r11, #12" );

601

602 /* Check the values are as expected. */

603 __asm volatile( " cmp r11, #10\n"

604 " bne set_error_led\n"

605 " cmp r0, #11\n"

606 " bne set_error_led\n"

607 " cmp r1, #12\n"

608 " bne set_error_led\n"

609 " cmp r2, #13\n"

610 " bne set_error_led\n"

611 " cmp r3, #14\n"

612 " bne set_error_led\n"

613 " cmp r4, #15\n"

614 " bne set_error_led\n"

615 " cmp r5, #16\n"

616 " bne set_error_led\n"

617 " cmp r6, #17\n"

618 " bne set_error_led\n"

619 " cmp r7, #18\n"

620 " bne set_error_led\n"

621 " cmp r8, #19\n"

622 " bne set_error_led\n"

623 " cmp r9, #20\n"

624 " bne set_error_led\n"

625 " cmp r10, #21\n"

626 " bne set_error_led\n"

627 " cmp r12, #22\n"

628 " bne set_error_led\n"

629 " bx lr" );

630

631 __asm volatile( "set_error_led:\n"

632 " push {r14}\n"

633 " ldr r1, =vSetErrorLED\n"

634 " blx r1\n"

635 " pop {r14}\n"

636 " bx lr" );

637 }

638 /*-----------------------------------------------------------*/