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/*
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	FreeRTOS.org V4.2.1 - Copyright (C) 2003-2007 Richard Barry.
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	This file is part of the FreeRTOS.org distribution.
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	FreeRTOS.org is free software; you can redistribute it and/or modify
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	it under the terms of the GNU General Public License as published by
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	the Free Software Foundation; either version 2 of the License, or
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	(at your option) any later version.
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	FreeRTOS.org is distributed in the hope that it will be useful,
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	but WITHOUT ANY WARRANTY; without even the implied warranty of
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	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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	GNU General Public License for more details.
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	You should have received a copy of the GNU General Public License
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	along with FreeRTOS.org; if not, write to the Free Software
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	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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	A special exception to the GPL can be applied should you wish to distribute
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	a combined work that includes FreeRTOS.org, without being obliged to provide
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	the source code for any proprietary components.  See the licensing section
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	of http://www.FreeRTOS.org for full details of how and when the exception
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	can be applied.
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	***************************************************************************
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	See http://www.FreeRTOS.org for documentation, latest information, license
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	and contact details.  Please ensure to read the configuration and relevant
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	port sections of the online documentation.
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	Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
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	with commercial development and support options.
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	***************************************************************************
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*/
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#ifndef CO_ROUTINE_H
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#define CO_ROUTINE_H
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38
#include "list.h"
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/* Used to hide the implementation of the co-routine control block.  The
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control block structure however has to be included in the header due to
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the macro implementation of the co-routine functionality. */
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typedef void *xCoRoutineHandle;
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/* Defines the prototype to which co-routine functions must conform. */
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typedef void (*crCOROUTINE_CODE) (xCoRoutineHandle, unsigned portBASE_TYPE);
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typedef struct corCoRoutineControlBlock
49
{
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  crCOROUTINE_CODE pxCoRoutineFunction;
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  xListItem xGenericListItem;	/*< List item used to place the CRCB in ready and blocked queues. */
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  xListItem xEventListItem;	/*< List item used to place the CRCB in event lists. */
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  unsigned portBASE_TYPE uxPriority;	/*< The priority of the co-routine in relation to other co-routines. */
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  unsigned portBASE_TYPE uxIndex;	/*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */
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  unsigned portSHORT uxState;	/*< Used internally by the co-routine implementation. */
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} corCRCB;			/* Co-routine control block.  Note must be identical in size down to uxPriority with tskTCB. */
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58
/**
59
 * croutine. h
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 *<pre>
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 portBASE_TYPE xCoRoutineCreate(
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                                 crCOROUTINE_CODE pxCoRoutineCode,
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                                 unsigned portBASE_TYPE uxPriority,
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                                 unsigned portBASE_TYPE uxIndex
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                               );</pre>
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 *
67
 * Create a new co-routine and add it to the list of co-routines that are
68
 * ready to run.
69
 *
70
 * @param pxCoRoutineCode Pointer to the co-routine function.  Co-routine
71
 * functions require special syntax - see the co-routine section of the WEB
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 * documentation for more information.
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 *
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 * @param uxPriority The priority with respect to other co-routines at which
75
 *  the co-routine will run.
76
 *
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.
80
 *
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.
83
 *
84
 * Example usage:
85
   <pre>
86
 // Co-routine to be created.
87
 void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
88
 {
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 // 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 };
93

    
94
     // Must start every co-routine with a call to crSTART();
95
     crSTART( xHandle );
96

    
97
     for( ;; )
98
     {
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 ] );
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         crDELAY( xHandle, uxFlashRates[ uxIndex ] );
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     }
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108
     // Must end every co-routine with a call to crEND();
109
     crEND();
110
 }
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112
 // Function that creates two co-routines.
113
 void vOtherFunction( void )
114
 {
115
 unsigned char ucParameterToPass;
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 xTaskHandle xHandle;
117
		
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.
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     for( uxIndex = 0; uxIndex < 2; uxIndex++ )
122
     {
123
         xCoRoutineCreate( vFlashCoRoutine, 0, uxIndex );
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     }
125
 }
126
   </pre>
127
 * \defgroup xCoRoutineCreate xCoRoutineCreate
128
 * \ingroup Tasks
129
 */
130
signed portBASE_TYPE xCoRoutineCreate (crCOROUTINE_CODE pxCoRoutineCode,
131
				       unsigned portBASE_TYPE uxPriority,
132
				       unsigned portBASE_TYPE uxIndex);
133

    
134

    
135
/**
136
 * croutine. h
137
 *<pre>
138
 void vCoRoutineSchedule( void );</pre>
139
 *
140
 * Run a co-routine.
141
 *
142
 * vCoRoutineSchedule() executes the highest priority co-routine that is able
143
 * to run.  The co-routine will execute until it either blocks, yields or is
144
 * preempted by a task.  Co-routines execute cooperatively so one
145
 * co-routine cannot be preempted by another, but can be preempted by a task.
146
 *
147
 * If an application comprises of both tasks and co-routines then
148
 * vCoRoutineSchedule should be called from the idle task (in an idle task
149
 * hook).
150
 *
151
 * Example usage:
152
   <pre>
153
 // This idle task hook will schedule a co-routine each time it is called.
154
 // The rest of the idle task will execute between co-routine calls.
155
 void vApplicationIdleHook( void )
156
 {
157
	vCoRoutineSchedule();
158
 }
159

    
160
 // Alternatively, if you do not require any other part of the idle task to
161
 // execute, the idle task hook can call vCoRoutineScheduler() within an
162
 // infinite loop.
163
 void vApplicationIdleHook( void )
164
 {
165
    for( ;; )
166
    {
167
        vCoRoutineSchedule();
168
    }
169
 }
170
 </pre>
171
 * \defgroup vCoRoutineSchedule vCoRoutineSchedule
172
 * \ingroup Tasks
173
 */
174
void vCoRoutineSchedule (void);
175

    
176
/**
177
 * croutine. h
178
 * <pre>
179
 crSTART( xCoRoutineHandle xHandle );</pre>
180
 *
181
 * This macro MUST always be called at the start of a co-routine function.
182
 *
183
 * Example usage:
184
   <pre>
185
 // Co-routine to be created.
186
 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
187
 {
188
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
189
 static portLONG ulAVariable;
190

    
191
     // Must start every co-routine with a call to crSTART();
192
     crSTART( xHandle );
193

    
194
     for( ;; )
195
     {
196
          // Co-routine functionality goes here.
197
     }
198

    
199
     // Must end every co-routine with a call to crEND();
200
     crEND();
201
 }</pre>
202
 * \defgroup crSTART crSTART
203
 * \ingroup Tasks
204
 */
205
#define crSTART( pxCRCB ) switch( ( ( corCRCB * )pxCRCB )->uxState ) { case 0:
206

    
207
/**
208
 * croutine. h
209
 * <pre>
210
 crEND();</pre>
211
 *
212
 * This macro MUST always be called at the end of a co-routine function.
213
 *
214
 * Example usage:
215
   <pre>
216
 // Co-routine to be created.
217
 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
218
 {
219
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
220
 static portLONG ulAVariable;
221

    
222
     // Must start every co-routine with a call to crSTART();
223
     crSTART( xHandle );
224

    
225
     for( ;; )
226
     {
227
          // Co-routine functionality goes here.
228
     }
229

    
230
     // Must end every co-routine with a call to crEND();
231
     crEND();
232
 }</pre>
233
 * \defgroup crSTART crSTART
234
 * \ingroup Tasks
235
 */
236
#define crEND() }
237

    
238
/*
239
 * These macros are intended for internal use by the co-routine implementation
240
 * only.  The macros should not be used directly by application writers.
241
 */
242
#define crSET_STATE0( xHandle ) ( ( corCRCB * )xHandle)->uxState = (__LINE__ * 2); return; case (__LINE__ * 2):
243
#define crSET_STATE1( xHandle ) ( ( corCRCB * )xHandle)->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1):
244

    
245
/**
246
 * croutine. h
247
 *<pre>
248
 crDELAY( xCoRoutineHandle xHandle, portTickType xTicksToDelay );</pre>
249
 *
250
 * Delay a co-routine for a fixed period of time.
251
 *
252
 * crDELAY can only be called from the co-routine function itself - not
253
 * from within a function called by the co-routine function.  This is because
254
 * co-routines do not maintain their own stack.
255
 *
256
 * @param xHandle The handle of the co-routine to delay.  This is the xHandle
257
 * parameter of the co-routine function.
258
 *
259
 * @param xTickToDelay The number of ticks that the co-routine should delay
260
 * for.  The actual amount of time this equates to is defined by
261
 * configTICK_RATE_HZ (set in FreeRTOSConfig.h).  The constant portTICK_RATE_MS
262
 * can be used to convert ticks to milliseconds.
263
 *
264
 * Example usage:
265
   <pre>
266
 // Co-routine to be created.
267
 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
268
 {
269
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
270
 // This may not be necessary for const variables.
271
 // We are to delay for 200ms.
272
 static const xTickType xDelayTime = 200 / portTICK_RATE_MS;
273

    
274
     // Must start every co-routine with a call to crSTART();
275
     crSTART( xHandle );
276

    
277
     for( ;; )
278
     {
279
        // Delay for 200ms.
280
        crDELAY( xHandle, xDelayTime );
281

    
282
        // Do something here.
283
     }
284

    
285
     // Must end every co-routine with a call to crEND();
286
     crEND();
287
 }</pre>
288
 * \defgroup crDELAY crDELAY
289
 * \ingroup Tasks
290
 */
291
#define crDELAY( xHandle, xTicksToDelay )												\
292
	if( xTicksToDelay > 0 )																\
293
	{																					\
294
		vCoRoutineAddToDelayedList( xTicksToDelay, NULL );								\
295
	}																					\
296
	crSET_STATE0( xHandle );
297

    
298
/**
299
 * <pre>
300
 crQUEUE_SEND(
301
                  xCoRoutineHandle xHandle,
302
                  xQueueHandle pxQueue,
303
                  void *pvItemToQueue,
304
                  portTickType xTicksToWait,
305
                  portBASE_TYPE *pxResult
306
             )</pre>
307
 *
308
 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
309
 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
310
 *
311
 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
312
 * xQueueSend() and xQueueReceive() can only be used from tasks.
313
 *
314
 * crQUEUE_SEND can only be called from the co-routine function itself - not
315
 * from within a function called by the co-routine function.  This is because
316
 * co-routines do not maintain their own stack.
317
 *
318
 * See the co-routine section of the WEB documentation for information on
319
 * passing data between tasks and co-routines and between ISR's and
320
 * co-routines.
321
 *
322
 * @param xHandle The handle of the calling co-routine.  This is the xHandle
323
 * parameter of the co-routine function.
324
 *
325
 * @param pxQueue The handle of the queue on which the data will be posted.
326
 * The handle is obtained as the return value when the queue is created using
327
 * the xQueueCreate() API function.
328
 *
329
 * @param pvItemToQueue A pointer to the data being posted onto the queue.
330
 * The number of bytes of each queued item is specified when the queue is
331
 * created.  This number of bytes is copied from pvItemToQueue into the queue
332
 * itself.
333
 *
334
 * @param xTickToDelay The number of ticks that the co-routine should block
335
 * to wait for space to become available on the queue, should space not be
336
 * available immediately. The actual amount of time this equates to is defined
337
 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h).  The constant
338
 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see example
339
 * below).
340
 *
341
 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
342
 * data was successfully posted onto the queue, otherwise it will be set to an
343
 * error defined within ProjDefs.h.
344
 *
345
 * Example usage:
346
   <pre>
347
 // Co-routine function that blocks for a fixed period then posts a number onto
348
 // a queue.
349
 static void prvCoRoutineFlashTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
350
 {
351
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
352
 static portBASE_TYPE xNumberToPost = 0;
353
 static portBASE_TYPE xResult;
354

    
355
    // Co-routines must begin with a call to crSTART().
356
    crSTART( xHandle );
357

    
358
    for( ;; )
359
    {
360
        // This assumes the queue has already been created.
361
        crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult );
362

    
363
        if( xResult != pdPASS )
364
        {
365
            // The message was not posted!
366
        }
367

    
368
        // Increment the number to be posted onto the queue.
369
        xNumberToPost++;
370

    
371
        // Delay for 100 ticks.
372
        crDELAY( xHandle, 100 );
373
    }
374

    
375
    // Co-routines must end with a call to crEND().
376
    crEND();
377
 }</pre>
378
 * \defgroup crQUEUE_SEND crQUEUE_SEND
379
 * \ingroup Tasks
380
 */
381
#define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult )			\
382
{																						\
383
	*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, xTicksToWait );					\
384
	if( *pxResult == errQUEUE_BLOCKED )													\
385
	{																					\
386
		crSET_STATE0( xHandle );														\
387
		*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, 0 );							\
388
	}																					\
389
	if( *pxResult == errQUEUE_YIELD )													\
390
	{																					\
391
		crSET_STATE1( xHandle );														\
392
		*pxResult = pdPASS;																\
393
	}																					\
394
}
395

    
396
/**
397
 * croutine. h
398
 * <pre>
399
  crQUEUE_RECEIVE(
400
                     xCoRoutineHandle xHandle,
401
                     xQueueHandle pxQueue,
402
                     void *pvBuffer,
403
                     portTickType xTicksToWait,
404
                     portBASE_TYPE *pxResult
405
                 )</pre>
406
 *
407
 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
408
 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
409
 *
410
 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
411
 * xQueueSend() and xQueueReceive() can only be used from tasks.
412
 *
413
 * crQUEUE_RECEIVE can only be called from the co-routine function itself - not
414
 * from within a function called by the co-routine function.  This is because
415
 * co-routines do not maintain their own stack.
416
 *
417
 * See the co-routine section of the WEB documentation for information on
418
 * passing data between tasks and co-routines and between ISR's and
419
 * co-routines.
420
 *
421
 * @param xHandle The handle of the calling co-routine.  This is the xHandle
422
 * parameter of the co-routine function.
423
 *
424
 * @param pxQueue The handle of the queue from which the data will be received.
425
 * The handle is obtained as the return value when the queue is created using
426
 * the xQueueCreate() API function.
427
 *
428
 * @param pvBuffer The buffer into which the received item is to be copied.
429
 * The number of bytes of each queued item is specified when the queue is
430
 * created.  This number of bytes is copied into pvBuffer.
431
 *
432
 * @param xTickToDelay The number of ticks that the co-routine should block
433
 * to wait for data to become available from the queue, should data not be
434
 * available immediately. The actual amount of time this equates to is defined
435
 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h).  The constant
436
 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see the
437
 * crQUEUE_SEND example).
438
 *
439
 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
440
 * data was successfully retrieved from the queue, otherwise it will be set to
441
 * an error code as defined within ProjDefs.h.
442
 *
443
 * Example usage:
444
 <pre>
445
 // A co-routine receives the number of an LED to flash from a queue.  It
446
 // blocks on the queue until the number is received.
447
 static void prvCoRoutineFlashWorkTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
448
 {
449
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
450
 static portBASE_TYPE xResult;
451
 static unsigned portBASE_TYPE uxLEDToFlash;
452

    
453
    // All co-routines must start with a call to crSTART().
454
    crSTART( xHandle );
455

    
456
    for( ;; )
457
    {
458
        // Wait for data to become available on the queue.
459
        crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
460

    
461
        if( xResult == pdPASS )
462
        {
463
            // We received the LED to flash - flash it!
464
            vParTestToggleLED( uxLEDToFlash );
465
        }
466
    }
467

    
468
    crEND();
469
 }</pre>
470
 * \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE
471
 * \ingroup Tasks
472
 */
473
#define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult )			\
474
{																						\
475
	*pxResult = xQueueCRReceive( pxQueue, pvBuffer, xTicksToWait );						\
476
	if( *pxResult == errQUEUE_BLOCKED ) 												\
477
	{																					\
478
		crSET_STATE0( xHandle );														\
479
		*pxResult = xQueueCRReceive( pxQueue, pvBuffer, 0 );							\
480
	}																					\
481
	if( *pxResult == errQUEUE_YIELD )													\
482
	{																					\
483
		crSET_STATE1( xHandle );														\
484
		*pxResult = pdPASS;																\
485
	}																					\
486
}
487

    
488
/**
489
 * croutine. h
490
 * <pre>
491
  crQUEUE_SEND_FROM_ISR(
492
                            xQueueHandle pxQueue,
493
                            void *pvItemToQueue,
494
                            portBASE_TYPE xCoRoutinePreviouslyWoken
495
                       )</pre>
496
 *
497
 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
498
 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
499
 * functions used by tasks.
500
 *
501
 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
502
 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
503
 * xQueueReceiveFromISR() can only be used to pass data between a task and and
504
 * ISR.
505
 *
506
 * crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue
507
 * that is being used from within a co-routine.
508
 *
509
 * See the co-routine section of the WEB documentation for information on
510
 * passing data between tasks and co-routines and between ISR's and
511
 * co-routines.
512
 *
513
 * @param xQueue The handle to the queue on which the item is to be posted.
514
 *
515
 * @param pvItemToQueue A pointer to the item that is to be placed on the
516
 * queue.  The size of the items the queue will hold was defined when the
517
 * queue was created, so this many bytes will be copied from pvItemToQueue
518
 * into the queue storage area.
519
 *
520
 * @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto
521
 * the same queue multiple times from a single interrupt.  The first call
522
 * should always pass in pdFALSE.  Subsequent calls should pass in
523
 * the value returned from the previous call.
524
 *
525
 * @return pdTRUE if a co-routine was woken by posting onto the queue.  This is
526
 * used by the ISR to determine if a context switch may be required following
527
 * the ISR.
528
 *
529
 * Example usage:
530
 <pre>
531
 // A co-routine that blocks on a queue waiting for characters to be received.
532
 static void vReceivingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
533
 {
534
 portCHAR cRxedChar;
535
 portBASE_TYPE xResult;
536

    
537
     // All co-routines must start with a call to crSTART().
538
     crSTART( xHandle );
539

    
540
     for( ;; )
541
     {
542
         // Wait for data to become available on the queue.  This assumes the
543
         // queue xCommsRxQueue has already been created!
544
         crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
545

    
546
         // Was a character received?
547
         if( xResult == pdPASS )
548
         {
549
             // Process the character here.
550
         }
551
     }
552

    
553
     // All co-routines must end with a call to crEND().
554
     crEND();
555
 }
556

    
557
 // An ISR that uses a queue to send characters received on a serial port to
558
 // a co-routine.
559
 void vUART_ISR( void )
560
 {
561
 portCHAR cRxedChar;
562
 portBASE_TYPE xCRWokenByPost = pdFALSE;
563

    
564
     // We loop around reading characters until there are none left in the UART.
565
     while( UART_RX_REG_NOT_EMPTY() )
566
     {
567
         // Obtain the character from the UART.
568
         cRxedChar = UART_RX_REG;
569

    
570
         // Post the character onto a queue.  xCRWokenByPost will be pdFALSE
571
         // the first time around the loop.  If the post causes a co-routine
572
         // to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE.
573
         // In this manner we can ensure that if more than one co-routine is
574
         // blocked on the queue only one is woken by this ISR no matter how
575
         // many characters are posted to the queue.
576
         xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost );
577
     }
578
 }</pre>
579
 * \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR
580
 * \ingroup Tasks
581
 */
582
#define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken )
583

    
584

    
585
/**
586
 * croutine. h
587
 * <pre>
588
  crQUEUE_SEND_FROM_ISR(
589
                            xQueueHandle pxQueue,
590
                            void *pvBuffer,
591
                            portBASE_TYPE * pxCoRoutineWoken
592
                       )</pre>
593
 *
594
 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
595
 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
596
 * functions used by tasks.
597
 *
598
 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
599
 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
600
 * xQueueReceiveFromISR() can only be used to pass data between a task and and
601
 * ISR.
602
 *
603
 * crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data
604
 * from a queue that is being used from within a co-routine (a co-routine
605
 * posted to the queue).
606
 *
607
 * See the co-routine section of the WEB documentation for information on
608
 * passing data between tasks and co-routines and between ISR's and
609
 * co-routines.
610
 *
611
 * @param xQueue The handle to the queue on which the item is to be posted.
612
 *
613
 * @param pvBuffer A pointer to a buffer into which the received item will be
614
 * placed.  The size of the items the queue will hold was defined when the
615
 * queue was created, so this many bytes will be copied from the queue into
616
 * pvBuffer.
617
 *
618
 * @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become
619
 * available on the queue.  If crQUEUE_RECEIVE_FROM_ISR causes such a
620
 * co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise
621
 * *pxCoRoutineWoken will remain unchanged.
622
 *
623
 * @return pdTRUE an item was successfully received from the queue, otherwise
624
 * pdFALSE.
625
 *
626
 * Example usage:
627
 <pre>
628
 // A co-routine that posts a character to a queue then blocks for a fixed
629
 // period.  The character is incremented each time.
630
 static void vSendingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
631
 {
632
 // cChar holds its value while this co-routine is blocked and must therefore
633
 // be declared static.
634
 static portCHAR cCharToTx = 'a';
635
 portBASE_TYPE xResult;
636

    
637
     // All co-routines must start with a call to crSTART().
638
     crSTART( xHandle );
639

    
640
     for( ;; )
641
     {
642
         // Send the next character to the queue.
643
         crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult );
644

    
645
         if( xResult == pdPASS )
646
         {
647
             // The character was successfully posted to the queue.
648
         }
649
		 else
650
		 {
651
			// Could not post the character to the queue.
652
		 }
653

    
654
         // Enable the UART Tx interrupt to cause an interrupt in this
655
		 // hypothetical UART.  The interrupt will obtain the character
656
		 // from the queue and send it.
657
		 ENABLE_RX_INTERRUPT();
658

    
659
		 // Increment to the next character then block for a fixed period.
660
		 // cCharToTx will maintain its value across the delay as it is
661
		 // declared static.
662
		 cCharToTx++;
663
		 if( cCharToTx > 'x' )
664
		 {
665
			cCharToTx = 'a';
666
		 }
667
		 crDELAY( 100 );
668
     }
669

    
670
     // All co-routines must end with a call to crEND().
671
     crEND();
672
 }
673

    
674
 // An ISR that uses a queue to receive characters to send on a UART.
675
 void vUART_ISR( void )
676
 {
677
 portCHAR cCharToTx;
678
 portBASE_TYPE xCRWokenByPost = pdFALSE;
679

    
680
     while( UART_TX_REG_EMPTY() )
681
     {
682
         // Are there any characters in the queue waiting to be sent?
683
		 // xCRWokenByPost will automatically be set to pdTRUE if a co-routine
684
		 // is woken by the post - ensuring that only a single co-routine is
685
		 // woken no matter how many times we go around this loop.
686
         if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) )
687
		 {
688
			 SEND_CHARACTER( cCharToTx );
689
		 }
690
     }
691
 }</pre>
692
 * \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR
693
 * \ingroup Tasks
694
 */
695
#define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( pxQueue, pvBuffer, pxCoRoutineWoken )
696

    
697
/*
698
 * This function is intended for internal use by the co-routine macros only.
699
 * The macro nature of the co-routine implementation requires that the
700
 * prototype appears here.  The function should not be used by application
701
 * writers.
702
 *
703
 * Removes the current co-routine from its ready list and places it in the
704
 * appropriate delayed list.
705
 */
706
void vCoRoutineAddToDelayedList (portTickType xTicksToDelay,
707
				 xList * pxEventList);
708

    
709
/*
710
 * This function is intended for internal use by the queue implementation only.
711
 * The function should not be used by application writers.
712
 *
713
 * Removes the highest priority co-routine from the event list and places it in
714
 * the pending ready list.
715
 */
716
signed portBASE_TYPE xCoRoutineRemoveFromEventList (const xList *
717
						    pxEventList);
718

    
719

    
720
#endif /* CO_ROUTINE_H */
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