begriffs open source - cmsis-freertos/blob - Demo/ARM7_AT91SAM7S64

151 AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_US0, serINTERRUPT_LEVEL, AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE, ( void (*)( void ) ) vSerialISREntry );

152 AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_US0 );

153 }

154 portEXIT_CRITICAL();

155 }

156 else

157 {

158 xReturn = ( xComPortHandle ) 0;

159 }

160

161 /* This demo file only supports a single port but we have to return

162 something to comply with the standard demo header file. */

163 return xReturn;

164 }

165 /*-----------------------------------------------------------*/

166

167 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )

168 {

169 /* The port handle is not required as this driver only supports one port. */

170 ( void ) pxPort;

171

172 /* Get the next character from the buffer. Return false if no characters

173 are available, or arrive before xBlockTime expires. */

174 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )

175 {

176 return pdTRUE;

177 }

178 else

179 {

180 return pdFALSE;

181 }

182 }

183 /*-----------------------------------------------------------*/

184

185 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )

186 {

187 signed char *pxNext;

188

189 /* A couple of parameters that this port does not use. */

190 ( void ) usStringLength;

191 ( void ) pxPort;

192

193 /* NOTE: This implementation does not handle the queue being full as no

194 block time is used! */

195

196 /* The port handle is not required as this driver only supports UART0. */

197 ( void ) pxPort;

198

199 /* Send each character in the string, one at a time. */

200 pxNext = ( signed char * ) pcString;

201 while( *pxNext )

202 {

203 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );

204 pxNext++;

205 }

206 }

207 /*-----------------------------------------------------------*/

208

209 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )

210 {

211 /* Place the character in the queue of characters to be transmitted. */

212 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )

213 {

214 return pdFAIL;

215 }

216

217 /* Turn on the Tx interrupt so the ISR will remove the character from the

218 queue and send it. This does not need to be in a critical section as

219 if the interrupt has already removed the character the next interrupt

220 will simply turn off the Tx interrupt again. */

221 vInterruptOn();

222

223 return pdPASS;

224 }

225 /*-----------------------------------------------------------*/

226

227 void vSerialClose( xComPortHandle xPort )

228 {

229 /* Not supported as not required by the demo application. */

230 }

231 /*-----------------------------------------------------------*/

232

233 /* Serial port ISR. This can cause a context switch so is not defined as a

234 standard ISR using the __irq keyword. Instead a wrapper function is defined

235 within serialISR.s79 which in turn calls this function. See the port

236 documentation on the FreeRTOS.org website for more information. */

237 __arm void vSerialISR( void )

238 {

239 unsigned long ulStatus;

240 signed char cChar;

241 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

242

243 /* What caused the interrupt? */

244 ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR;

245

246 if( ulStatus & AT91C_US_TXRDY )

247 {

248 /* The interrupt was caused by the THR becoming empty. Are there any

249 more characters to transmit? */

250 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )

251 {

252 /* A character was retrieved from the queue so can be sent to the

253 THR now. */

254 serCOM0->US_THR = cChar;

255 }

256 else

257 {

258 /* Queue empty, nothing to send so turn off the Tx interrupt. */

259 vInterruptOff();

260 }

261 }

262

263 if( ulStatus & AT91C_US_RXRDY )

264 {

265 /* The interrupt was caused by a character being received. Grab the

266 character from the RHR and place it in the queue or received

267 characters. */

268 cChar = serCOM0->US_RHR;

269 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );

270 }

271

272 /* If a task was woken by either a character being received or a character

273 being transmitted then we may need to switch to another task. */

274 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );

275

276 /* End the interrupt in the AIC. */

277 AT91C_BASE_AIC->AIC_EOICR = 0;

278 }

283