2 FreeRTOS.org V4.8.0 - Copyright (C) 2003-2008 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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14 GNU General Public License for more details.
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26 ***************************************************************************
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27 ***************************************************************************
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33 ***************************************************************************
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34 ***************************************************************************
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36 Please ensure to read the configuration and relevant port sections of the
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37 online documentation.
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39 http://www.FreeRTOS.org - Documentation, latest information, license and
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42 http://www.SafeRTOS.com - A version that is certified for use in safety
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45 http://www.OpenRTOS.com - Commercial support, development, porting,
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46 licensing and training services.
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48 #ifndef CO_ROUTINE_H
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49 #define CO_ROUTINE_H
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57 /* Used to hide the implementation of the co-routine control block. The
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58 control block structure however has to be included in the header due to
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59 the macro implementation of the co-routine functionality. */
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60 typedef void * xCoRoutineHandle;
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62 /* Defines the prototype to which co-routine functions must conform. */
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63 typedef void (*crCOROUTINE_CODE)( xCoRoutineHandle, unsigned portBASE_TYPE );
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65 typedef struct corCoRoutineControlBlock
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67 crCOROUTINE_CODE pxCoRoutineFunction;
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68 xListItem xGenericListItem; /*< List item used to place the CRCB in ready and blocked queues. */
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69 xListItem xEventListItem; /*< List item used to place the CRCB in event lists. */
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70 unsigned portBASE_TYPE uxPriority; /*< The priority of the co-routine in relation to other co-routines. */
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71 unsigned portBASE_TYPE uxIndex; /*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */
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72 unsigned portSHORT uxState; /*< Used internally by the co-routine implementation. */
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73 } corCRCB; /* Co-routine control block. Note must be identical in size down to uxPriority with tskTCB. */
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78 portBASE_TYPE xCoRoutineCreate(
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79 crCOROUTINE_CODE pxCoRoutineCode,
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80 unsigned portBASE_TYPE uxPriority,
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81 unsigned portBASE_TYPE uxIndex
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84 * Create a new co-routine and add it to the list of co-routines that are
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87 * @param pxCoRoutineCode Pointer to the co-routine function. Co-routine
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88 * functions require special syntax - see the co-routine section of the WEB
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89 * documentation for more information.
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91 * @param uxPriority The priority with respect to other co-routines at which
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92 * the co-routine will run.
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94 * @param uxIndex Used to distinguish between different co-routines that
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95 * execute the same function. See the example below and the co-routine section
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96 * of the WEB documentation for further information.
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98 * @return pdPASS if the co-routine was successfully created and added to a ready
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99 * list, otherwise an error code defined with ProjDefs.h.
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103 // Co-routine to be created.
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104 void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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106 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
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107 // This may not be necessary for const variables.
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108 static const char cLedToFlash[ 2 ] = { 5, 6 };
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109 static const portTickType xTimeToDelay[ 2 ] = { 200, 400 };
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111 // Must start every co-routine with a call to crSTART();
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112 crSTART( xHandle );
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116 // This co-routine just delays for a fixed period, then toggles
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117 // an LED. Two co-routines are created using this function, so
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118 // the uxIndex parameter is used to tell the co-routine which
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119 // LED to flash and how long to delay. This assumes xQueue has
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120 // already been created.
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121 vParTestToggleLED( cLedToFlash[ uxIndex ] );
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122 crDELAY( xHandle, uxFlashRates[ uxIndex ] );
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125 // Must end every co-routine with a call to crEND();
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129 // Function that creates two co-routines.
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130 void vOtherFunction( void )
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132 unsigned char ucParameterToPass;
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133 xTaskHandle xHandle;
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135 // Create two co-routines at priority 0. The first is given index 0
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136 // so (from the code above) toggles LED 5 every 200 ticks. The second
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137 // is given index 1 so toggles LED 6 every 400 ticks.
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138 for( uxIndex = 0; uxIndex < 2; uxIndex++ )
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140 xCoRoutineCreate( vFlashCoRoutine, 0, uxIndex );
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144 * \defgroup xCoRoutineCreate xCoRoutineCreate
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147 signed portBASE_TYPE xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, unsigned portBASE_TYPE uxPriority, unsigned portBASE_TYPE uxIndex );
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153 void vCoRoutineSchedule( void );</pre>
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155 * Run a co-routine.
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157 * vCoRoutineSchedule() executes the highest priority co-routine that is able
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158 * to run. The co-routine will execute until it either blocks, yields or is
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159 * preempted by a task. Co-routines execute cooperatively so one
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160 * co-routine cannot be preempted by another, but can be preempted by a task.
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162 * If an application comprises of both tasks and co-routines then
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163 * vCoRoutineSchedule should be called from the idle task (in an idle task
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168 // This idle task hook will schedule a co-routine each time it is called.
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169 // The rest of the idle task will execute between co-routine calls.
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170 void vApplicationIdleHook( void )
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172 vCoRoutineSchedule();
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175 // Alternatively, if you do not require any other part of the idle task to
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176 // execute, the idle task hook can call vCoRoutineScheduler() within an
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178 void vApplicationIdleHook( void )
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182 vCoRoutineSchedule();
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186 * \defgroup vCoRoutineSchedule vCoRoutineSchedule
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189 void vCoRoutineSchedule( void );
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194 crSTART( xCoRoutineHandle xHandle );</pre>
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196 * This macro MUST always be called at the start of a co-routine function.
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200 // Co-routine to be created.
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201 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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203 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
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204 static portLONG ulAVariable;
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206 // Must start every co-routine with a call to crSTART();
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207 crSTART( xHandle );
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211 // Co-routine functionality goes here.
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214 // Must end every co-routine with a call to crEND();
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217 * \defgroup crSTART crSTART
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220 #define crSTART( pxCRCB ) switch( ( ( corCRCB * )pxCRCB )->uxState ) { case 0:
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227 * This macro MUST always be called at the end of a co-routine function.
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231 // Co-routine to be created.
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232 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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234 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
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235 static portLONG ulAVariable;
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237 // Must start every co-routine with a call to crSTART();
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238 crSTART( xHandle );
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242 // Co-routine functionality goes here.
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245 // Must end every co-routine with a call to crEND();
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248 * \defgroup crSTART crSTART
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254 * These macros are intended for internal use by the co-routine implementation
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255 * only. The macros should not be used directly by application writers.
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257 #define crSET_STATE0( xHandle ) ( ( corCRCB * )xHandle)->uxState = (__LINE__ * 2); return; case (__LINE__ * 2):
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258 #define crSET_STATE1( xHandle ) ( ( corCRCB * )xHandle)->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1):
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263 crDELAY( xCoRoutineHandle xHandle, portTickType xTicksToDelay );</pre>
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265 * Delay a co-routine for a fixed period of time.
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267 * crDELAY can only be called from the co-routine function itself - not
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268 * from within a function called by the co-routine function. This is because
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269 * co-routines do not maintain their own stack.
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271 * @param xHandle The handle of the co-routine to delay. This is the xHandle
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272 * parameter of the co-routine function.
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274 * @param xTickToDelay The number of ticks that the co-routine should delay
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275 * for. The actual amount of time this equates to is defined by
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276 * configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_RATE_MS
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277 * can be used to convert ticks to milliseconds.
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281 // Co-routine to be created.
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282 void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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284 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
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285 // This may not be necessary for const variables.
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286 // We are to delay for 200ms.
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287 static const xTickType xDelayTime = 200 / portTICK_RATE_MS;
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289 // Must start every co-routine with a call to crSTART();
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290 crSTART( xHandle );
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294 // Delay for 200ms.
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295 crDELAY( xHandle, xDelayTime );
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297 // Do something here.
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300 // Must end every co-routine with a call to crEND();
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303 * \defgroup crDELAY crDELAY
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306 #define crDELAY( xHandle, xTicksToDelay ) \
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307 if( xTicksToDelay > 0 ) \
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309 vCoRoutineAddToDelayedList( xTicksToDelay, NULL ); \
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311 crSET_STATE0( xHandle );
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316 xCoRoutineHandle xHandle,
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317 xQueueHandle pxQueue,
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318 void *pvItemToQueue,
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319 portTickType xTicksToWait,
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320 portBASE_TYPE *pxResult
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323 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
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324 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
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326 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
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327 * xQueueSend() and xQueueReceive() can only be used from tasks.
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329 * crQUEUE_SEND can only be called from the co-routine function itself - not
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330 * from within a function called by the co-routine function. This is because
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331 * co-routines do not maintain their own stack.
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333 * See the co-routine section of the WEB documentation for information on
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334 * passing data between tasks and co-routines and between ISR's and
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337 * @param xHandle The handle of the calling co-routine. This is the xHandle
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338 * parameter of the co-routine function.
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340 * @param pxQueue The handle of the queue on which the data will be posted.
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341 * The handle is obtained as the return value when the queue is created using
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342 * the xQueueCreate() API function.
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344 * @param pvItemToQueue A pointer to the data being posted onto the queue.
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345 * The number of bytes of each queued item is specified when the queue is
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346 * created. This number of bytes is copied from pvItemToQueue into the queue
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349 * @param xTickToDelay The number of ticks that the co-routine should block
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350 * to wait for space to become available on the queue, should space not be
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351 * available immediately. The actual amount of time this equates to is defined
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352 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
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353 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see example
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356 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
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357 * data was successfully posted onto the queue, otherwise it will be set to an
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358 * error defined within ProjDefs.h.
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362 // Co-routine function that blocks for a fixed period then posts a number onto
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364 static void prvCoRoutineFlashTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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366 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
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367 static portBASE_TYPE xNumberToPost = 0;
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368 static portBASE_TYPE xResult;
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370 // Co-routines must begin with a call to crSTART().
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371 crSTART( xHandle );
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375 // This assumes the queue has already been created.
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376 crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult );
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378 if( xResult != pdPASS )
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380 // The message was not posted!
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383 // Increment the number to be posted onto the queue.
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386 // Delay for 100 ticks.
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387 crDELAY( xHandle, 100 );
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390 // Co-routines must end with a call to crEND().
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393 * \defgroup crQUEUE_SEND crQUEUE_SEND
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396 #define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult ) \
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398 *pxResult = xQueueCRSend( pxQueue, pvItemToQueue, xTicksToWait ); \
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399 if( *pxResult == errQUEUE_BLOCKED ) \
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401 crSET_STATE0( xHandle ); \
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402 *pxResult = xQueueCRSend( pxQueue, pvItemToQueue, 0 ); \
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404 if( *pxResult == errQUEUE_YIELD ) \
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406 crSET_STATE1( xHandle ); \
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407 *pxResult = pdPASS; \
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415 xCoRoutineHandle xHandle,
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416 xQueueHandle pxQueue,
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418 portTickType xTicksToWait,
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419 portBASE_TYPE *pxResult
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422 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
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423 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
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425 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
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426 * xQueueSend() and xQueueReceive() can only be used from tasks.
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428 * crQUEUE_RECEIVE can only be called from the co-routine function itself - not
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429 * from within a function called by the co-routine function. This is because
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430 * co-routines do not maintain their own stack.
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432 * See the co-routine section of the WEB documentation for information on
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433 * passing data between tasks and co-routines and between ISR's and
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436 * @param xHandle The handle of the calling co-routine. This is the xHandle
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437 * parameter of the co-routine function.
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439 * @param pxQueue The handle of the queue from which the data will be received.
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440 * The handle is obtained as the return value when the queue is created using
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441 * the xQueueCreate() API function.
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443 * @param pvBuffer The buffer into which the received item is to be copied.
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444 * The number of bytes of each queued item is specified when the queue is
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445 * created. This number of bytes is copied into pvBuffer.
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447 * @param xTickToDelay The number of ticks that the co-routine should block
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448 * to wait for data to become available from the queue, should data not be
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449 * available immediately. The actual amount of time this equates to is defined
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450 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
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451 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see the
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452 * crQUEUE_SEND example).
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454 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
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455 * data was successfully retrieved from the queue, otherwise it will be set to
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456 * an error code as defined within ProjDefs.h.
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460 // A co-routine receives the number of an LED to flash from a queue. It
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461 // blocks on the queue until the number is received.
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462 static void prvCoRoutineFlashWorkTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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464 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
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465 static portBASE_TYPE xResult;
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466 static unsigned portBASE_TYPE uxLEDToFlash;
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468 // All co-routines must start with a call to crSTART().
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469 crSTART( xHandle );
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473 // Wait for data to become available on the queue.
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474 crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
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476 if( xResult == pdPASS )
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478 // We received the LED to flash - flash it!
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479 vParTestToggleLED( uxLEDToFlash );
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485 * \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE
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488 #define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult ) \
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490 *pxResult = xQueueCRReceive( pxQueue, pvBuffer, xTicksToWait ); \
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491 if( *pxResult == errQUEUE_BLOCKED ) \
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493 crSET_STATE0( xHandle ); \
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494 *pxResult = xQueueCRReceive( pxQueue, pvBuffer, 0 ); \
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496 if( *pxResult == errQUEUE_YIELD ) \
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498 crSET_STATE1( xHandle ); \
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499 *pxResult = pdPASS; \
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506 crQUEUE_SEND_FROM_ISR(
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507 xQueueHandle pxQueue,
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508 void *pvItemToQueue,
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509 portBASE_TYPE xCoRoutinePreviouslyWoken
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512 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
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513 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
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514 * functions used by tasks.
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516 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
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517 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
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518 * xQueueReceiveFromISR() can only be used to pass data between a task and and
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521 * crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue
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522 * that is being used from within a co-routine.
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524 * See the co-routine section of the WEB documentation for information on
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525 * passing data between tasks and co-routines and between ISR's and
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528 * @param xQueue The handle to the queue on which the item is to be posted.
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530 * @param pvItemToQueue A pointer to the item that is to be placed on the
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531 * queue. The size of the items the queue will hold was defined when the
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532 * queue was created, so this many bytes will be copied from pvItemToQueue
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533 * into the queue storage area.
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535 * @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto
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536 * the same queue multiple times from a single interrupt. The first call
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537 * should always pass in pdFALSE. Subsequent calls should pass in
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538 * the value returned from the previous call.
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540 * @return pdTRUE if a co-routine was woken by posting onto the queue. This is
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541 * used by the ISR to determine if a context switch may be required following
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546 // A co-routine that blocks on a queue waiting for characters to be received.
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547 static void vReceivingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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549 portCHAR cRxedChar;
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550 portBASE_TYPE xResult;
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552 // All co-routines must start with a call to crSTART().
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553 crSTART( xHandle );
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557 // Wait for data to become available on the queue. This assumes the
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558 // queue xCommsRxQueue has already been created!
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559 crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
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561 // Was a character received?
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562 if( xResult == pdPASS )
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564 // Process the character here.
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568 // All co-routines must end with a call to crEND().
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572 // An ISR that uses a queue to send characters received on a serial port to
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574 void vUART_ISR( void )
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576 portCHAR cRxedChar;
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577 portBASE_TYPE xCRWokenByPost = pdFALSE;
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579 // We loop around reading characters until there are none left in the UART.
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580 while( UART_RX_REG_NOT_EMPTY() )
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582 // Obtain the character from the UART.
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583 cRxedChar = UART_RX_REG;
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585 // Post the character onto a queue. xCRWokenByPost will be pdFALSE
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586 // the first time around the loop. If the post causes a co-routine
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587 // to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE.
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588 // In this manner we can ensure that if more than one co-routine is
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589 // blocked on the queue only one is woken by this ISR no matter how
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590 // many characters are posted to the queue.
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591 xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost );
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594 * \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR
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597 #define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken )
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603 crQUEUE_SEND_FROM_ISR(
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604 xQueueHandle pxQueue,
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606 portBASE_TYPE * pxCoRoutineWoken
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609 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
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610 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
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611 * functions used by tasks.
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613 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
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614 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
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615 * xQueueReceiveFromISR() can only be used to pass data between a task and and
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618 * crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data
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619 * from a queue that is being used from within a co-routine (a co-routine
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620 * posted to the queue).
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622 * See the co-routine section of the WEB documentation for information on
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623 * passing data between tasks and co-routines and between ISR's and
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626 * @param xQueue The handle to the queue on which the item is to be posted.
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628 * @param pvBuffer A pointer to a buffer into which the received item will be
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629 * placed. The size of the items the queue will hold was defined when the
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630 * queue was created, so this many bytes will be copied from the queue into
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633 * @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become
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634 * available on the queue. If crQUEUE_RECEIVE_FROM_ISR causes such a
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635 * co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise
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636 * *pxCoRoutineWoken will remain unchanged.
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638 * @return pdTRUE an item was successfully received from the queue, otherwise
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643 // A co-routine that posts a character to a queue then blocks for a fixed
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644 // period. The character is incremented each time.
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645 static void vSendingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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647 // cChar holds its value while this co-routine is blocked and must therefore
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648 // be declared static.
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649 static portCHAR cCharToTx = 'a';
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650 portBASE_TYPE xResult;
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652 // All co-routines must start with a call to crSTART().
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653 crSTART( xHandle );
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657 // Send the next character to the queue.
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658 crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult );
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660 if( xResult == pdPASS )
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662 // The character was successfully posted to the queue.
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666 // Could not post the character to the queue.
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669 // Enable the UART Tx interrupt to cause an interrupt in this
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670 // hypothetical UART. The interrupt will obtain the character
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671 // from the queue and send it.
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672 ENABLE_RX_INTERRUPT();
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674 // Increment to the next character then block for a fixed period.
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675 // cCharToTx will maintain its value across the delay as it is
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676 // declared static.
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678 if( cCharToTx > 'x' )
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685 // All co-routines must end with a call to crEND().
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689 // An ISR that uses a queue to receive characters to send on a UART.
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690 void vUART_ISR( void )
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692 portCHAR cCharToTx;
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693 portBASE_TYPE xCRWokenByPost = pdFALSE;
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695 while( UART_TX_REG_EMPTY() )
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697 // Are there any characters in the queue waiting to be sent?
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698 // xCRWokenByPost will automatically be set to pdTRUE if a co-routine
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699 // is woken by the post - ensuring that only a single co-routine is
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700 // woken no matter how many times we go around this loop.
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701 if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) )
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703 SEND_CHARACTER( cCharToTx );
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707 * \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR
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710 #define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( pxQueue, pvBuffer, pxCoRoutineWoken )
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713 * This function is intended for internal use by the co-routine macros only.
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714 * The macro nature of the co-routine implementation requires that the
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715 * prototype appears here. The function should not be used by application
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718 * Removes the current co-routine from its ready list and places it in the
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719 * appropriate delayed list.
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721 void vCoRoutineAddToDelayedList( portTickType xTicksToDelay, xList *pxEventList );
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724 * This function is intended for internal use by the queue implementation only.
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725 * The function should not be used by application writers.
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727 * Removes the highest priority co-routine from the event list and places it in
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728 * the pending ready list.
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730 signed portBASE_TYPE xCoRoutineRemoveFromEventList( const xList *pxEventList );
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736 #endif /* CO_ROUTINE_H */
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