2 FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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68 * Creates six tasks that operate on three queues as follows:
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70 * The first two tasks send and receive an incrementing number to/from a queue.
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71 * One task acts as a producer and the other as the consumer. The consumer is a
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72 * higher priority than the producer and is set to block on queue reads. The queue
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73 * only has space for one item - as soon as the producer posts a message on the
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74 * queue the consumer will unblock, pre-empt the producer, and remove the item.
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76 * The second two tasks work the other way around. Again the queue used only has
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77 * enough space for one item. This time the consumer has a lower priority than the
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78 * producer. The producer will try to post on the queue blocking when the queue is
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79 * full. When the consumer wakes it will remove the item from the queue, causing
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80 * the producer to unblock, pre-empt the consumer, and immediately re-fill the
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83 * The last two tasks use the same queue producer and consumer functions. This time the queue has
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84 * enough space for lots of items and the tasks operate at the same priority. The
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85 * producer will execute, placing items into the queue. The consumer will start
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86 * executing when either the queue becomes full (causing the producer to block) or
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87 * a context switch occurs (tasks of the same priority will time slice).
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95 + The second set of tasks were created the wrong way around. This has been
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100 #include <stdlib.h>
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102 /* Scheduler include files. */
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103 #include "FreeRTOS.h"
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107 /* Demo program include files. */
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108 #include "BlockQ.h"
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110 #define blckqSTACK_SIZE configMINIMAL_STACK_SIZE
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111 #define blckqNUM_TASK_SETS ( 3 )
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113 /* Structure used to pass parameters to the blocking queue tasks. */
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114 typedef struct BLOCKING_QUEUE_PARAMETERS
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116 xQueueHandle xQueue; /*< The queue to be used by the task. */
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117 portTickType xBlockTime; /*< The block time to use on queue reads/writes. */
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118 volatile short *psCheckVariable; /*< Incremented on each successful cycle to check the task is still running. */
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119 } xBlockingQueueParameters;
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121 /* Task function that creates an incrementing number and posts it on a queue. */
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122 static portTASK_FUNCTION_PROTO( vBlockingQueueProducer, pvParameters );
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124 /* Task function that removes the incrementing number from a queue and checks that
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125 it is the expected number. */
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126 static portTASK_FUNCTION_PROTO( vBlockingQueueConsumer, pvParameters );
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128 /* Variables which are incremented each time an item is removed from a queue, and
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129 found to be the expected value.
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130 These are used to check that the tasks are still running. */
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131 static volatile short sBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( unsigned short ) 0, ( unsigned short ) 0, ( unsigned short ) 0 };
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133 /* Variable which are incremented each time an item is posted on a queue. These
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134 are used to check that the tasks are still running. */
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135 static volatile short sBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( unsigned short ) 0, ( unsigned short ) 0, ( unsigned short ) 0 };
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137 /*-----------------------------------------------------------*/
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139 void vStartBlockingQueueTasks( unsigned portBASE_TYPE uxPriority )
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141 xBlockingQueueParameters *pxQueueParameters1, *pxQueueParameters2;
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142 xBlockingQueueParameters *pxQueueParameters3, *pxQueueParameters4;
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143 xBlockingQueueParameters *pxQueueParameters5, *pxQueueParameters6;
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144 const unsigned portBASE_TYPE uxQueueSize1 = 1, uxQueueSize5 = 5;
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145 const portTickType xBlockTime = ( portTickType ) 1000 / portTICK_RATE_MS;
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146 const portTickType xDontBlock = ( portTickType ) 0;
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148 /* Create the first two tasks as described at the top of the file. */
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150 /* First create the structure used to pass parameters to the consumer tasks. */
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151 pxQueueParameters1 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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153 /* Create the queue used by the first two tasks to pass the incrementing number.
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154 Pass a pointer to the queue in the parameter structure. */
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155 pxQueueParameters1->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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157 /* The consumer is created first so gets a block time as described above. */
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158 pxQueueParameters1->xBlockTime = xBlockTime;
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160 /* Pass in the variable that this task is going to increment so we can check it
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161 is still running. */
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162 pxQueueParameters1->psCheckVariable = &( sBlockingConsumerCount[ 0 ] );
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164 /* Create the structure used to pass parameters to the producer task. */
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165 pxQueueParameters2 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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167 /* Pass the queue to this task also, using the parameter structure. */
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168 pxQueueParameters2->xQueue = pxQueueParameters1->xQueue;
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170 /* The producer is not going to block - as soon as it posts the consumer will
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171 wake and remove the item so the producer should always have room to post. */
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172 pxQueueParameters2->xBlockTime = xDontBlock;
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174 /* Pass in the variable that this task is going to increment so we can check
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175 it is still running. */
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176 pxQueueParameters2->psCheckVariable = &( sBlockingProducerCount[ 0 ] );
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179 /* Note the producer has a lower priority than the consumer when the tasks are
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181 xTaskCreate( vBlockingQueueConsumer, ( signed char * ) "QConsB1", blckqSTACK_SIZE, ( void * ) pxQueueParameters1, uxPriority, NULL );
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182 xTaskCreate( vBlockingQueueProducer, ( signed char * ) "QProdB2", blckqSTACK_SIZE, ( void * ) pxQueueParameters2, tskIDLE_PRIORITY, NULL );
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186 /* Create the second two tasks as described at the top of the file. This uses
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187 the same mechanism but reverses the task priorities. */
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189 pxQueueParameters3 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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190 pxQueueParameters3->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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191 pxQueueParameters3->xBlockTime = xDontBlock;
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192 pxQueueParameters3->psCheckVariable = &( sBlockingProducerCount[ 1 ] );
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194 pxQueueParameters4 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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195 pxQueueParameters4->xQueue = pxQueueParameters3->xQueue;
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196 pxQueueParameters4->xBlockTime = xBlockTime;
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197 pxQueueParameters4->psCheckVariable = &( sBlockingConsumerCount[ 1 ] );
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199 xTaskCreate( vBlockingQueueConsumer, ( signed char * ) "QConsB3", blckqSTACK_SIZE, ( void * ) pxQueueParameters3, tskIDLE_PRIORITY, NULL );
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200 xTaskCreate( vBlockingQueueProducer, ( signed char * ) "QProdB4", blckqSTACK_SIZE, ( void * ) pxQueueParameters4, uxPriority, NULL );
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204 /* Create the last two tasks as described above. The mechanism is again just
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205 the same. This time both parameter structures are given a block time. */
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206 pxQueueParameters5 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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207 pxQueueParameters5->xQueue = xQueueCreate( uxQueueSize5, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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208 pxQueueParameters5->xBlockTime = xBlockTime;
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209 pxQueueParameters5->psCheckVariable = &( sBlockingProducerCount[ 2 ] );
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211 pxQueueParameters6 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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212 pxQueueParameters6->xQueue = pxQueueParameters5->xQueue;
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213 pxQueueParameters6->xBlockTime = xBlockTime;
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214 pxQueueParameters6->psCheckVariable = &( sBlockingConsumerCount[ 2 ] );
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216 xTaskCreate( vBlockingQueueProducer, ( signed char * ) "QProdB5", blckqSTACK_SIZE, ( void * ) pxQueueParameters5, tskIDLE_PRIORITY, NULL );
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217 xTaskCreate( vBlockingQueueConsumer, ( signed char * ) "QConsB6", blckqSTACK_SIZE, ( void * ) pxQueueParameters6, tskIDLE_PRIORITY, NULL );
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219 /*-----------------------------------------------------------*/
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221 static portTASK_FUNCTION( vBlockingQueueProducer, pvParameters )
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223 unsigned short usValue = 0;
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224 xBlockingQueueParameters *pxQueueParameters;
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225 short sErrorEverOccurred = pdFALSE;
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227 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;
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231 if( xQueueSend( pxQueueParameters->xQueue, ( void * ) &usValue, pxQueueParameters->xBlockTime ) != pdPASS )
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233 sErrorEverOccurred = pdTRUE;
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237 /* We have successfully posted a message, so increment the variable
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238 used to check we are still running. */
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239 if( sErrorEverOccurred == pdFALSE )
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241 ( *pxQueueParameters->psCheckVariable )++;
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244 /* Increment the variable we are going to post next time round. The
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245 consumer will expect the numbers to follow in numerical order. */
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250 /*-----------------------------------------------------------*/
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252 static portTASK_FUNCTION( vBlockingQueueConsumer, pvParameters )
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254 unsigned short usData, usExpectedValue = 0;
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255 xBlockingQueueParameters *pxQueueParameters;
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256 short sErrorEverOccurred = pdFALSE;
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258 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;
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262 if( xQueueReceive( pxQueueParameters->xQueue, &usData, pxQueueParameters->xBlockTime ) == pdPASS )
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264 if( usData != usExpectedValue )
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267 usExpectedValue = usData;
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269 sErrorEverOccurred = pdTRUE;
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273 /* We have successfully received a message, so increment the
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274 variable used to check we are still running. */
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275 if( sErrorEverOccurred == pdFALSE )
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277 ( *pxQueueParameters->psCheckVariable )++;
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280 /* Increment the value we expect to remove from the queue next time
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287 /*-----------------------------------------------------------*/
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289 /* This is called to check that all the created tasks are still running. */
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290 portBASE_TYPE xAreBlockingQueuesStillRunning( void )
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292 static short sLastBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( unsigned short ) 0, ( unsigned short ) 0, ( unsigned short ) 0 };
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293 static short sLastBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( unsigned short ) 0, ( unsigned short ) 0, ( unsigned short ) 0 };
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294 portBASE_TYPE xReturn = pdPASS, xTasks;
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296 /* Not too worried about mutual exclusion on these variables as they are 16
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297 bits and we are only reading them. We also only care to see if they have
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300 Loop through each check variable to and return pdFALSE if any are found not
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301 to have changed since the last call. */
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303 for( xTasks = 0; xTasks < blckqNUM_TASK_SETS; xTasks++ )
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305 if( sBlockingConsumerCount[ xTasks ] == sLastBlockingConsumerCount[ xTasks ] )
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309 sLastBlockingConsumerCount[ xTasks ] = sBlockingConsumerCount[ xTasks ];
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312 if( sBlockingProducerCount[ xTasks ] == sLastBlockingProducerCount[ xTasks ] )
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316 sLastBlockingProducerCount[ xTasks ] = sBlockingProducerCount[ xTasks ];
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