begriffs open source - cmsis-freertos/blob - Demo/CORTEX_LM3S316

1 /*

4

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

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67 1 tab == 4 spaces!

68 */

69

70 /*

71 * This demo application creates eight co-routines and four tasks (five

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

73 * hook. The application is limited in size to allow its compilation using

74 * the KickStart version of the IAR compiler.

75 *

76 * Six of the created co-routines are the standard 'co-routine flash'

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

78 * documented on the FreeRTOS.org WEB site.

79 *

80 * The 'LCD Task' waits on a message queue for messages informing it what and

81 * where to display text. This is the only task that accesses the LCD

82 * so mutual exclusion is guaranteed.

83 *

84 * The 'LCD Message Task' periodically sends strings to the LCD Task using

85 * the message queue. The strings are rotated to form a short message and

86 * are written to the top row of the LCD.

87 *

88 * The 'ADC Co-routine' periodically reads the ADC input that is connected to

89 * the light sensor, forms a short message from the value, and then sends this

90 * message to the LCD Task using the same message queue. The ADC readings are

91 * displayed on the bottom row of the LCD.

92 *

93 * The eighth co-routine and final task control the transmission and reception

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

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

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

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

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

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

100 *

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

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

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

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

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

106 * therefore more likely to highlight any problems.

107 *

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

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

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

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

112 *

113 * In addition the idle task makes repetitive calls to

114 * vSetAndCheckRegisters(). This simply loads the general purpose registers

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

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

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

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

119 * mechanism.

120 *

121 */

122

123 /* standard include files. */

124 #include <stdio.h>

125

126 /* Scheduler include files. */

127 #include "FreeRTOS.h"

128 #include "task.h"

129 #include "queue.h"

130 #include "croutine.h"

131

132 /* Demo application include files. */

133 #include "partest.h"

134 #include "crflash.h"

135 #include "commstest.h"

136

137 /* Library include files. */

138 #include "DriverLib.h"

139

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

141 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_PERIOD_MS )

142

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

144 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_PERIOD_MS )

145

146 #define mainADC_DELAY ( 200 / portTICK_PERIOD_MS )

147

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

149 #define mainNUM_FLASH_CO_ROUTINES ( 5 )

150

151 /* The length of the queue used to send messages to the LCD task. */

152 #define mainLCD_QUEUE_LEN ( 3 )

153

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

155 string on UART 0. */

156 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )

157 #define mainADC_CO_ROUTINE_PRIORITY ( 2 )

158

159 /* Only one of each co-routine is created so its index is not important. */

160 #define mainTX_CO_ROUTINE_INDEX ( 0 )

161 #define mainADC_CO_ROUTINE_INDEX ( 0 )

162

163 /* The task priorities. */

164 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )

165 #define mainMSG_TASK_PRIORITY ( mainLCD_TASK_PRIORITY - 1 )

166 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )

167

168 /* The LCD had two rows. */

169 #define mainTOP_ROW 0

170 #define mainBOTTOM_ROW 1

171

172 /* Dimension for the buffer into which the ADC value string is written. */

173 #define mainMAX_ADC_STRING_LEN 20

174

175 /* The LED that is lit should an error be detected in any of the tasks or

176 co-routines. */

177 #define mainFAIL_LED ( 7 )

178

179 /*-----------------------------------------------------------*/

180

181 /*

182 * The task that displays text on the LCD.

183 */

184 static void prvLCDTask( void * pvParameters );

185

186 /*

187 * The task that sends messages to be displayed on the top row of the LCD.

188 */

189 static void prvLCDMessageTask( void * pvParameters );

190

191 /*

192 * The co-routine that reads the ADC and sends messages for display on the

193 * bottom row of the LCD.

194 */

195 static void prvADCCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex );

196

197 /*

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

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

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

201 */

202 extern void vSetAndCheckRegisters( void );

203

204 /*

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

206 */

207 void vSetErrorLED( void );

208

209 /*

210 * Thread safe write to the PDC.

211 */

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

213

214 /*

215 * Sets up the hardware used by the demo.

216 */

217 static void prvSetupHardware( void );

218

219

220 /*-----------------------------------------------------------*/

221

222 /* The structure that is passed on the LCD message queue. */

223 typedef struct

224 {

225 char **ppcMessageToDisplay; /*<< Points to a char* pointing to the message to display. */

226 portBASE_TYPE xRow; /*<< The row on which the message should be displayed. */

227 } xLCDMessage;

228

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

230 defined within this file. */

231 unsigned portBASE_TYPE uxErrorStatus = pdPASS;

232

233 /* The queue used to transmit messages to the LCD task. */

234 static QueueHandle_t xLCDQueue;

235

236 /*-----------------------------------------------------------*/

237

238 /*

239 * Setup the hardware, create the tasks/co-routines, then start the scheduler.

240 */

241 void main( void )

242 {

243 /* Create the queue used by tasks wanting to write to the LCD. */

244 xLCDQueue = xQueueCreate( mainLCD_QUEUE_LEN, sizeof( xLCDMessage ) );

245

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

247 prvSetupHardware();

248

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

250 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );

251

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

253 on the UART and the task that receives them, as described at the top of

254 this file. */

255 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );

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

257

258 /* Create the task that waits for messages to display on the LCD, plus the

259 task and co-routine that send messages for display (as described at the top

260 of this file. */

261 xTaskCreate( prvLCDTask, "LCD", configMINIMAL_STACK_SIZE, ( void * ) &xLCDQueue, mainLCD_TASK_PRIORITY, NULL );

262 xTaskCreate( prvLCDMessageTask, "MSG", configMINIMAL_STACK_SIZE, ( void * ) &xLCDQueue, mainMSG_TASK_PRIORITY, NULL );

263 xCoRoutineCreate( prvADCCoRoutine, mainADC_CO_ROUTINE_PRIORITY, mainADC_CO_ROUTINE_INDEX );

264

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

266 vTaskStartScheduler();

267

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

269 scheduler. */

270 for( ;; );

271 }

272 /*-----------------------------------------------------------*/

273

274 static void prvLCDMessageTask( void * pvParameters )

275 {

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

277 char *pcStringsToDisplay[] = {

278 "IAR ",

279 "Stellaris ",

280 "Demo ",

281 "www.FreeRTOS.org",

282 ""

283 };

284

285 QueueHandle_t *pxLCDQueue;

286 xLCDMessage xMessageToSend;

287 portBASE_TYPE xIndex = 0;

288

289 /* To test the parameter passing mechanism, the queue on which messages are

290 posted is passed in as a parameter even though it is available as a file

291 scope variable anyway. */

292 pxLCDQueue = ( QueueHandle_t * ) pvParameters;

293

294 for( ;; )

295 {

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

297 vTaskDelay( mainSTRING_WRITE_DELAY );

298

299 /* Create the message object to send to the LCD task. */

300 xMessageToSend.ppcMessageToDisplay = &pcStringsToDisplay[ xIndex ];

301 xMessageToSend.xRow = mainTOP_ROW;

302

303 /* Post the message to be displayed. */

304 if( !xQueueSend( *pxLCDQueue, ( void * ) &xMessageToSend, 0 ) )

305 {

306 uxErrorStatus = pdFAIL;

307 }

308

309 /* Move onto the next message, wrapping when necessary. */

310 xIndex++;

311 if( *( pcStringsToDisplay[ xIndex ] ) == 0x00 )

312 {

313 xIndex = 0;

314

315 /* Delay longer before going back to the start of the messages. */

316 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );

317 }

318 }

319 }

320 /*-----------------------------------------------------------*/

321

322 void prvLCDTask( void * pvParameters )

323 {

324 unsigned portBASE_TYPE uxIndex;

325 QueueHandle_t *pxLCDQueue;

326 xLCDMessage xReceivedMessage;

327 char *pcString;

328 const unsigned char ucCFGData[] = {

329 0x30, /* Set data bus to 8-bits. */

330 0x30,

331 0x30,

332 0x3C, /* Number of lines/font. */

333 0x08, /* Display off. */

334 0x01, /* Display clear. */

335 0x06, /* Entry mode [cursor dir][shift]. */

336 0x0C /* Display on [display on][curson on][blinking on]. */

337 };

338

339 /* To test the parameter passing mechanism, the queue on which messages are

340 received is passed in as a parameter even though it is available as a file

341 scope variable anyway. */

342 pxLCDQueue = ( QueueHandle_t * ) pvParameters;

343

344 /* Configure the LCD. */

345 uxIndex = 0;

346 while( uxIndex < sizeof( ucCFGData ) )

347 {

348 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );

349 uxIndex++;

350 vTaskDelay( mainCHAR_WRITE_DELAY );

351 }

352

353 /* Turn the LCD Backlight on. */

354 prvPDCWrite( PDC_CSR, 0x01 );

355

356 /* Clear display. */

357 vTaskDelay( mainCHAR_WRITE_DELAY );

358 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );

359

360 uxIndex = 0;

361 for( ;; )

362 {

363 /* Wait for a message to arrive. */

364 if( xQueueReceive( *pxLCDQueue, &xReceivedMessage, portMAX_DELAY ) )

365 {

366 /* Which row does the received message say to write to? */

367 PDCLCDSetPos( 0, xReceivedMessage.xRow );

368

369 /* Where is the string we are going to display? */

370 pcString = *xReceivedMessage.ppcMessageToDisplay;

371

372 while( *pcString )

373 {

374 /* Don't write out the string too quickly as LCD's are usually

375 pretty slow devices. */

376 vTaskDelay( mainCHAR_WRITE_DELAY );

377 prvPDCWrite( PDC_LCD_RAM, *pcString );

378 pcString++;

379 }

380 }

381 }

382 }

383 /*-----------------------------------------------------------*/

384

385 static void prvADCCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex )

386 {

387 static unsigned long ulADCValue;

388 static char cMessageBuffer[ mainMAX_ADC_STRING_LEN ];

389 static char *pcMessage;

390 static xLCDMessage xMessageToSend;

391

392 /* Co-routines MUST start with a call to crSTART(). */

393 crSTART( xHandle );

394

395 for( ;; )

396 {

397 /* Start an ADC conversion. */

398 ADCProcessorTrigger( ADC_BASE, 0 );

399

400 /* Simply delay - when we unblock the result should be available */

401 crDELAY( xHandle, mainADC_DELAY );

402

403 /* Get the ADC result. */

404 ADCSequenceDataGet( ADC_BASE, 0, &ulADCValue );

405

406 /* Create a string with the result. */

407 sprintf( cMessageBuffer, "ADC = %d ", ulADCValue );

408 pcMessage = cMessageBuffer;

409

410 /* Configure the message we are going to send for display. */

411 xMessageToSend.ppcMessageToDisplay = ( char** ) &pcMessage;

412 xMessageToSend.xRow = mainBOTTOM_ROW;

413

414 /* Send the string to the LCD task for display. We are sending

415 on a task queue so do not have the option to block. */

416 if( !xQueueSend( xLCDQueue, ( void * ) &xMessageToSend, 0 ) )

417 {

418 uxErrorStatus = pdFAIL;

419 }

420 }

421

422 /* Co-routines MUST end with a call to crEND(). */

423 crEND();

424 }

425 /*-----------------------------------------------------------*/

426

427 static void prvSetupHardware( void )

428 {

429 /* Setup the PLL. */

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

431

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

433 PDCInit();

434 vParTestInitialise();

435 vSerialInit();

436

437 /* The ADC is used to read the light sensor. */

438 SysCtlPeripheralEnable( SYSCTL_PERIPH_ADC );

439 ADCSequenceConfigure( ADC_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);

440 ADCSequenceStepConfigure( ADC_BASE, 0, 0, ADC_CTL_CH0 | ADC_CTL_END );

441 ADCSequenceEnable( ADC_BASE, 0 );

442

443 }

444 /*-----------------------------------------------------------*/

445

446 static void prvPDCWrite( char cAddress, char cData )

447 {

448 vTaskSuspendAll();

449 {

450 PDCWrite( cAddress, cData );

451 }

452 xTaskResumeAll();

453 }

454 /*-----------------------------------------------------------*/

455

456 void vSetErrorLED( void )

457 {

458 vParTestSetLED( mainFAIL_LED, pdTRUE );

459 }

460 /*-----------------------------------------------------------*/

461

462 void vApplicationIdleHook( void )

463 {

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

465 hook. */

466 for( ;; )

467 {

468 /* Schedule the co-routines. */

469 vCoRoutineSchedule();

470

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

472 vSetAndCheckRegisters();

473

474 /* See if the comms task and co-routine has found any errors. */

475 if( uxGetCommsStatus() != pdPASS )

476 {

477 vParTestSetLED( mainFAIL_LED, pdTRUE );

478 }

479 }

480 }

481 /*-----------------------------------------------------------*/