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40 /* Used to hide the implementation of the co-routine control block. The
41 control block structure however has to be included in the header due to
42 the macro implementation of the co-routine functionality. */
43 typedef void * xCoRoutineHandle;
45 /* Defines the prototype to which co-routine functions must conform. */
46 typedef void (*crCOROUTINE_CODE)( xCoRoutineHandle, unsigned portBASE_TYPE );
48 typedef struct corCoRoutineControlBlock
50 crCOROUTINE_CODE pxCoRoutineFunction;
51 xListItem xGenericListItem; /*< List item used to place the CRCB in ready and blocked queues. */
52 xListItem xEventListItem; /*< List item used to place the CRCB in event lists. */
53 unsigned portBASE_TYPE uxPriority; /*< The priority of the co-routine in relation to other co-routines. */
54 unsigned portBASE_TYPE uxIndex; /*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */
55 unsigned portSHORT uxState; /*< Used internally by the co-routine implementation. */
56 } corCRCB; /* Co-routine control block. Note must be identical in size down to uxPriority with tskTCB. */
61 portBASE_TYPE xCoRoutineCreate(
62 crCOROUTINE_CODE pxCoRoutineCode,
63 unsigned portBASE_TYPE uxPriority,
64 unsigned portBASE_TYPE uxIndex
67 * Create a new co-routine and add it to the list of co-routines that are
70 * @param pxCoRoutineCode Pointer to the co-routine function. Co-routine
71 * functions require special syntax - see the co-routine section of the WEB
72 * documentation for more information.
74 * @param uxPriority The priority with respect to other co-routines at which
75 * the co-routine will run.
77 * @param uxIndex Used to distinguish between different co-routines that
78 * execute the same function. See the example below and the co-routine section
79 * of the WEB documentation for further information.
81 * @return pdPASS if the co-routine was successfully created and added to a ready
82 * list, otherwise an error code defined with ProjDefs.h.
86 // Co-routine to be created.
87 void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
89 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
90 // This may not be necessary for const variables.
91 static const char cLedToFlash[ 2 ] = { 5, 6 };
92 static const portTickType xTimeToDelay[ 2 ] = { 200, 400 };
94 // Must start every co-routine with a call to crSTART();
99 // This co-routine just delays for a fixed period, then toggles
100 // an LED. Two co-routines are created using this function, so
101 // the uxIndex parameter is used to tell the co-routine which
102 // LED to flash and how long to delay. This assumes xQueue has
103 // already been created.
104 vParTestToggleLED( cLedToFlash[ uxIndex ] );
105 crDELAY( xHandle, uxFlashRates[ uxIndex ] );
108 // Must end every co-routine with a call to crEND();
112 // Function that creates two co-routines.
113 void vOtherFunction( void )
115 unsigned char ucParameterToPass;
118 // Create two co-routines at priority 0. The first is given index 0
119 // so (from the code above) toggles LED 5 every 200 ticks. The second
120 // is given index 1 so toggles LED 6 every 400 ticks.
121 for( uxIndex = 0; uxIndex < 2; uxIndex++ )
123 xCoRoutineCreate( vFlashCoRoutine, 0, uxIndex );
127 * \defgroup xCoRoutineCreate xCoRoutineCreate
130 signed portBASE_TYPE xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, unsigned portBASE_TYPE uxPriority, unsigned portBASE_TYPE uxIndex );
136 void vCoRoutineSchedule( void );</pre>
140 * vCoRoutineSchedule() executes the highest priority co-routine that is able
141 * to run. The co-routine will execute until it either blocks, yields or is
142 * preempted by a task. Co-routines execute cooperatively so one
143 * co-routine cannot be preempted by another, but can be preempted by a task.
145 * If an application comprises of both tasks and co-routines then
146 * vCoRoutineSchedule should be called from the idle task (in an idle task
151 // This idle task hook will schedule a co-routine each time it is called.
152 // The rest of the idle task will execute between co-routine calls.
153 void vApplicationIdleHook( void )
155 vCoRoutineSchedule();
158 // Alternatively, if you do not require any other part of the idle task to
159 // execute, the idle task hook can call vCoRoutineScheduler() within an
161 void vApplicationIdleHook( void )
165 vCoRoutineSchedule();
169 * \defgroup vCoRoutineSchedule vCoRoutineSchedule
172 void vCoRoutineSchedule( void );
177 crSTART( xCoRoutineHandle xHandle );</pre>
179 * This macro MUST always be called at the start of a co-routine function.
183 // Co-routine to be created.
184 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
186 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
187 static portLONG ulAVariable;
189 // Must start every co-routine with a call to crSTART();
194 // Co-routine functionality goes here.
197 // Must end every co-routine with a call to crEND();
200 * \defgroup crSTART crSTART
203 #define crSTART( pxCRCB ) switch( ( ( corCRCB * )pxCRCB )->uxState ) { case 0:
210 * This macro MUST always be called at the end of a co-routine function.
214 // Co-routine to be created.
215 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
217 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
218 static portLONG ulAVariable;
220 // Must start every co-routine with a call to crSTART();
225 // Co-routine functionality goes here.
228 // Must end every co-routine with a call to crEND();
231 * \defgroup crSTART crSTART
237 * These macros are intended for internal use by the co-routine implementation
238 * only. The macros should not be used directly by application writers.
240 #define crSET_STATE0( xHandle ) ( ( corCRCB * )xHandle)->uxState = (__LINE__ * 2); return; case (__LINE__ * 2):
241 #define crSET_STATE1( xHandle ) ( ( corCRCB * )xHandle)->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1):
246 crDELAY( xCoRoutineHandle xHandle, portTickType xTicksToDelay );</pre>
248 * Delay a co-routine for a fixed period of time.
250 * crDELAY can only be called from the co-routine function itself - not
251 * from within a function called by the co-routine function. This is because
252 * co-routines do not maintain their own stack.
254 * @param xHandle The handle of the co-routine to delay. This is the xHandle
255 * parameter of the co-routine function.
257 * @param xTickToDelay The number of ticks that the co-routine should delay
258 * for. The actual amount of time this equates to is defined by
259 * configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_RATE_MS
260 * can be used to convert ticks to milliseconds.
264 // Co-routine to be created.
265 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
267 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
268 // This may not be necessary for const variables.
269 // We are to delay for 200ms.
270 static const xTickType xDelayTime = 200 / portTICK_RATE_MS;
272 // Must start every co-routine with a call to crSTART();
278 crDELAY( xHandle, xDelayTime );
280 // Do something here.
283 // Must end every co-routine with a call to crEND();
286 * \defgroup crDELAY crDELAY
289 #define crDELAY( xHandle, xTicksToDelay ) \
290 if( xTicksToDelay > 0 ) \
292 vCoRoutineAddToDelayedList( xTicksToDelay, NULL ); \
294 crSET_STATE0( xHandle );
299 xCoRoutineHandle xHandle,
300 xQueueHandle pxQueue,
302 portTickType xTicksToWait,
303 portBASE_TYPE *pxResult
306 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
307 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
309 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
310 * xQueueSend() and xQueueReceive() can only be used from tasks.
312 * crQUEUE_SEND can only be called from the co-routine function itself - not
313 * from within a function called by the co-routine function. This is because
314 * co-routines do not maintain their own stack.
316 * See the co-routine section of the WEB documentation for information on
317 * passing data between tasks and co-routines and between ISR's and
320 * @param xHandle The handle of the calling co-routine. This is the xHandle
321 * parameter of the co-routine function.
323 * @param pxQueue The handle of the queue on which the data will be posted.
324 * The handle is obtained as the return value when the queue is created using
325 * the xQueueCreate() API function.
327 * @param pvItemToQueue A pointer to the data being posted onto the queue.
328 * The number of bytes of each queued item is specified when the queue is
329 * created. This number of bytes is copied from pvItemToQueue into the queue
332 * @param xTickToDelay The number of ticks that the co-routine should block
333 * to wait for space to become available on the queue, should space not be
334 * available immediately. The actual amount of time this equates to is defined
335 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
336 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see example
339 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
340 * data was successfully posted onto the queue, otherwise it will be set to an
341 * error defined within ProjDefs.h.
345 // Co-routine function that blocks for a fixed period then posts a number onto
347 static void prvCoRoutineFlashTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
349 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
350 static portBASE_TYPE xNumberToPost = 0;
351 static portBASE_TYPE xResult;
353 // Co-routines must begin with a call to crSTART().
358 // This assumes the queue has already been created.
359 crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult );
361 if( xResult != pdPASS )
363 // The message was not posted!
366 // Increment the number to be posted onto the queue.
369 // Delay for 100 ticks.
370 crDELAY( xHandle, 100 );
373 // Co-routines must end with a call to crEND().
376 * \defgroup crQUEUE_SEND crQUEUE_SEND
379 #define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult ) \
381 *pxResult = xQueueCRSend( pxQueue, pvItemToQueue, xTicksToWait ); \
382 if( *pxResult == errQUEUE_BLOCKED ) \
384 crSET_STATE0( xHandle ); \
385 *pxResult = xQueueCRSend( pxQueue, pvItemToQueue, 0 ); \
387 if( *pxResult == errQUEUE_YIELD ) \
389 crSET_STATE1( xHandle ); \
390 *pxResult = pdPASS; \
398 xCoRoutineHandle xHandle,
399 xQueueHandle pxQueue,
401 portTickType xTicksToWait,
402 portBASE_TYPE *pxResult
405 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
406 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
408 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
409 * xQueueSend() and xQueueReceive() can only be used from tasks.
411 * crQUEUE_RECEIVE can only be called from the co-routine function itself - not
412 * from within a function called by the co-routine function. This is because
413 * co-routines do not maintain their own stack.
415 * See the co-routine section of the WEB documentation for information on
416 * passing data between tasks and co-routines and between ISR's and
419 * @param xHandle The handle of the calling co-routine. This is the xHandle
420 * parameter of the co-routine function.
422 * @param pxQueue The handle of the queue from which the data will be received.
423 * The handle is obtained as the return value when the queue is created using
424 * the xQueueCreate() API function.
426 * @param pvBuffer The buffer into which the received item is to be copied.
427 * The number of bytes of each queued item is specified when the queue is
428 * created. This number of bytes is copied into pvBuffer.
430 * @param xTickToDelay The number of ticks that the co-routine should block
431 * to wait for data to become available from the queue, should data not be
432 * available immediately. The actual amount of time this equates to is defined
433 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
434 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see the
435 * crQUEUE_SEND example).
437 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
438 * data was successfully retrieved from the queue, otherwise it will be set to
439 * an error code as defined within ProjDefs.h.
443 // A co-routine receives the number of an LED to flash from a queue. It
444 // blocks on the queue until the number is received.
445 static void prvCoRoutineFlashWorkTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
447 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
448 static portBASE_TYPE xResult;
449 static unsigned portBASE_TYPE uxLEDToFlash;
451 // All co-routines must start with a call to crSTART().
456 // Wait for data to become available on the queue.
457 crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
459 if( xResult == pdPASS )
461 // We received the LED to flash - flash it!
462 vParTestToggleLED( uxLEDToFlash );
468 * \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE
471 #define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult ) \
473 *pxResult = xQueueCRReceive( pxQueue, pvBuffer, xTicksToWait ); \
474 if( *pxResult == errQUEUE_BLOCKED ) \
476 crSET_STATE0( xHandle ); \
477 *pxResult = xQueueCRReceive( pxQueue, pvBuffer, 0 ); \
479 if( *pxResult == errQUEUE_YIELD ) \
481 crSET_STATE1( xHandle ); \
482 *pxResult = pdPASS; \
489 crQUEUE_SEND_FROM_ISR(
490 xQueueHandle pxQueue,
492 portBASE_TYPE xCoRoutinePreviouslyWoken
495 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
496 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
497 * functions used by tasks.
499 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
500 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
501 * xQueueReceiveFromISR() can only be used to pass data between a task and and
504 * crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue
505 * that is being used from within a co-routine.
507 * See the co-routine section of the WEB documentation for information on
508 * passing data between tasks and co-routines and between ISR's and
511 * @param xQueue The handle to the queue on which the item is to be posted.
513 * @param pvItemToQueue A pointer to the item that is to be placed on the
514 * queue. The size of the items the queue will hold was defined when the
515 * queue was created, so this many bytes will be copied from pvItemToQueue
516 * into the queue storage area.
518 * @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto
519 * the same queue multiple times from a single interrupt. The first call
520 * should always pass in pdFALSE. Subsequent calls should pass in
521 * the value returned from the previous call.
523 * @return pdTRUE if a co-routine was woken by posting onto the queue. This is
524 * used by the ISR to determine if a context switch may be required following
529 // A co-routine that blocks on a queue waiting for characters to be received.
530 static void vReceivingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
533 portBASE_TYPE xResult;
535 // All co-routines must start with a call to crSTART().
540 // Wait for data to become available on the queue. This assumes the
541 // queue xCommsRxQueue has already been created!
542 crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
544 // Was a character received?
545 if( xResult == pdPASS )
547 // Process the character here.
551 // All co-routines must end with a call to crEND().
555 // An ISR that uses a queue to send characters received on a serial port to
557 void vUART_ISR( void )
560 portBASE_TYPE xCRWokenByPost = pdFALSE;
562 // We loop around reading characters until there are none left in the UART.
563 while( UART_RX_REG_NOT_EMPTY() )
565 // Obtain the character from the UART.
566 cRxedChar = UART_RX_REG;
568 // Post the character onto a queue. xCRWokenByPost will be pdFALSE
569 // the first time around the loop. If the post causes a co-routine
570 // to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE.
571 // In this manner we can ensure that if more than one co-routine is
572 // blocked on the queue only one is woken by this ISR no matter how
573 // many characters are posted to the queue.
574 xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost );
577 * \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR
580 #define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken )
586 crQUEUE_SEND_FROM_ISR(
587 xQueueHandle pxQueue,
589 portBASE_TYPE * pxCoRoutineWoken
592 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
593 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
594 * functions used by tasks.
596 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
597 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
598 * xQueueReceiveFromISR() can only be used to pass data between a task and and
601 * crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data
602 * from a queue that is being used from within a co-routine (a co-routine
603 * posted to the queue).
605 * See the co-routine section of the WEB documentation for information on
606 * passing data between tasks and co-routines and between ISR's and
609 * @param xQueue The handle to the queue on which the item is to be posted.
611 * @param pvBuffer A pointer to a buffer into which the received item will be
612 * placed. The size of the items the queue will hold was defined when the
613 * queue was created, so this many bytes will be copied from the queue into
616 * @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become
617 * available on the queue. If crQUEUE_RECEIVE_FROM_ISR causes such a
618 * co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise
619 * *pxCoRoutineWoken will remain unchanged.
621 * @return pdTRUE an item was successfully received from the queue, otherwise
626 // A co-routine that posts a character to a queue then blocks for a fixed
627 // period. The character is incremented each time.
628 static void vSendingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
630 // cChar holds its value while this co-routine is blocked and must therefore
631 // be declared static.
632 static portCHAR cCharToTx = 'a';
633 portBASE_TYPE xResult;
635 // All co-routines must start with a call to crSTART().
640 // Send the next character to the queue.
641 crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult );
643 if( xResult == pdPASS )
645 // The character was successfully posted to the queue.
649 // Could not post the character to the queue.
652 // Enable the UART Tx interrupt to cause an interrupt in this
653 // hypothetical UART. The interrupt will obtain the character
654 // from the queue and send it.
655 ENABLE_RX_INTERRUPT();
657 // Increment to the next character then block for a fixed period.
658 // cCharToTx will maintain its value across the delay as it is
661 if( cCharToTx > 'x' )
668 // All co-routines must end with a call to crEND().
672 // An ISR that uses a queue to receive characters to send on a UART.
673 void vUART_ISR( void )
676 portBASE_TYPE xCRWokenByPost = pdFALSE;
678 while( UART_TX_REG_EMPTY() )
680 // Are there any characters in the queue waiting to be sent?
681 // xCRWokenByPost will automatically be set to pdTRUE if a co-routine
682 // is woken by the post - ensuring that only a single co-routine is
683 // woken no matter how many times we go around this loop.
684 if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) )
686 SEND_CHARACTER( cCharToTx );
690 * \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR
693 #define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( pxQueue, pvBuffer, pxCoRoutineWoken )
696 * This function is intended for internal use by the co-routine macros only.
697 * The macro nature of the co-routine implementation requires that the
698 * prototype appears here. The function should not be used by application
701 * Removes the current co-routine from its ready list and places it in the
702 * appropriate delayed list.
704 void vCoRoutineAddToDelayedList( portTickType xTicksToDelay, xList *pxEventList );
707 * This function is intended for internal use by the queue implementation only.
708 * The function should not be used by application writers.
710 * Removes the highest priority co-routine from the event list and places it in
711 * the pending ready list.
713 signed portBASE_TYPE xCoRoutineRemoveFromEventList( const xList *pxEventList );
716 #endif /* CO_ROUTINE_H */