2 FreeRTOS.org V5.1.0 - 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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7 it under the terms of the GNU General Public License as published by
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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26 ***************************************************************************
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27 ***************************************************************************
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29 * SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
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32 * expedite your project. *
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34 ***************************************************************************
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35 ***************************************************************************
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37 Please ensure to read the configuration and relevant port sections of the
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38 online documentation.
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40 http://www.FreeRTOS.org - Documentation, latest information, license and
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43 http://www.SafeRTOS.com - A version that is certified for use in safety
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46 http://www.OpenRTOS.com - Commercial support, development, porting,
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47 licensing and training services.
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51 * This is a version of PollQ.c that uses the alternative (Alt) API.
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53 * Creates two tasks that communicate over a single queue. One task acts as a
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54 * producer, the other a consumer.
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56 * The producer loops for three iteration, posting an incrementing number onto the
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57 * queue each cycle. It then delays for a fixed period before doing exactly the
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60 * The consumer loops emptying the queue. Each item removed from the queue is
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61 * checked to ensure it contains the expected value. When the queue is empty it
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62 * blocks for a fixed period, then does the same again.
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64 * All queue access is performed without blocking. The consumer completely empties
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65 * the queue each time it runs so the producer should never find the queue full.
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67 * An error is flagged if the consumer obtains an unexpected value or the producer
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68 * find the queue is full.
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74 + Delay periods are now specified using variables and constants of
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75 portTickType rather than unsigned portLONG.
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80 /* Scheduler include files. */
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81 #include "FreeRTOS.h"
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85 /* Demo program include files. */
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86 #include "AltPollQ.h"
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88 #define pollqSTACK_SIZE configMINIMAL_STACK_SIZE
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89 #define pollqQUEUE_SIZE ( 10 )
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90 #define pollqPRODUCER_DELAY ( ( portTickType ) 200 / portTICK_RATE_MS )
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91 #define pollqCONSUMER_DELAY ( pollqPRODUCER_DELAY - ( portTickType ) ( 20 / portTICK_RATE_MS ) )
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92 #define pollqNO_DELAY ( ( portTickType ) 0 )
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93 #define pollqVALUES_TO_PRODUCE ( ( signed portBASE_TYPE ) 3 )
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94 #define pollqINITIAL_VALUE ( ( signed portBASE_TYPE ) 0 )
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96 /* The task that posts the incrementing number onto the queue. */
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97 static portTASK_FUNCTION_PROTO( vPolledQueueProducer, pvParameters );
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99 /* The task that empties the queue. */
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100 static portTASK_FUNCTION_PROTO( vPolledQueueConsumer, pvParameters );
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102 /* Variables that are used to check that the tasks are still running with no
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104 static volatile signed portBASE_TYPE xPollingConsumerCount = pollqINITIAL_VALUE, xPollingProducerCount = pollqINITIAL_VALUE;
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106 /*-----------------------------------------------------------*/
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108 void vStartAltPolledQueueTasks( unsigned portBASE_TYPE uxPriority )
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110 static xQueueHandle xPolledQueue;
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112 /* Create the queue used by the producer and consumer. */
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113 xPolledQueue = xQueueCreate( pollqQUEUE_SIZE, ( unsigned portBASE_TYPE ) sizeof( unsigned portSHORT ) );
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115 /* vQueueAddToRegistry() adds the queue to the queue registry, if one is
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116 in use. The queue registry is provided as a means for kernel aware
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117 debuggers to locate queues and has no purpose if a kernel aware debugger
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118 is not being used. The call to vQueueAddToRegistry() will be removed
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119 by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is
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120 defined to be less than 1. */
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121 vQueueAddToRegistry( xPolledQueue, ( signed portCHAR * ) "AltPollQueue" );
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124 /* Spawn the producer and consumer. */
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125 xTaskCreate( vPolledQueueConsumer, ( signed portCHAR * ) "QConsNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( xTaskHandle * ) NULL );
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126 xTaskCreate( vPolledQueueProducer, ( signed portCHAR * ) "QProdNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( xTaskHandle * ) NULL );
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128 /*-----------------------------------------------------------*/
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130 static portTASK_FUNCTION( vPolledQueueProducer, pvParameters )
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132 unsigned portSHORT usValue = ( unsigned portSHORT ) 0;
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133 signed portBASE_TYPE xError = pdFALSE, xLoop;
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136 void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
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138 const portCHAR * const pcTaskStartMsg = "Alt polling queue producer task started.\r\n";
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140 /* Queue a message for printing to say the task has started. */
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141 vPrintDisplayMessage( &pcTaskStartMsg );
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146 for( xLoop = 0; xLoop < pollqVALUES_TO_PRODUCE; xLoop++ )
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148 /* Send an incrementing number on the queue without blocking. */
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149 if( xQueueAltSendToBack( *( ( xQueueHandle * ) pvParameters ), ( void * ) &usValue, pollqNO_DELAY ) != pdPASS )
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151 /* We should never find the queue full so if we get here there
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152 has been an error. */
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157 if( xError == pdFALSE )
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159 /* If an error has ever been recorded we stop incrementing the
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161 portENTER_CRITICAL();
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162 xPollingProducerCount++;
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163 portEXIT_CRITICAL();
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166 /* Update the value we are going to post next time around. */
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171 /* Wait before we start posting again to ensure the consumer runs and
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172 empties the queue. */
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173 vTaskDelay( pollqPRODUCER_DELAY );
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175 } /*lint !e818 Function prototype must conform to API. */
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176 /*-----------------------------------------------------------*/
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178 static portTASK_FUNCTION( vPolledQueueConsumer, pvParameters )
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180 unsigned portSHORT usData, usExpectedValue = ( unsigned portSHORT ) 0;
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181 signed portBASE_TYPE xError = pdFALSE;
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184 void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
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186 const portCHAR * const pcTaskStartMsg = "Alt blocking queue consumer task started.\r\n";
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188 /* Queue a message for printing to say the task has started. */
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189 vPrintDisplayMessage( &pcTaskStartMsg );
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194 /* Loop until the queue is empty. */
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195 while( uxQueueMessagesWaiting( *( ( xQueueHandle * ) pvParameters ) ) )
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197 if( xQueueAltReceive( *( ( xQueueHandle * ) pvParameters ), &usData, pollqNO_DELAY ) == pdPASS )
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199 if( usData != usExpectedValue )
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201 /* This is not what we expected to receive so an error has
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205 /* Catch-up to the value we received so our next expected
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206 value should again be correct. */
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207 usExpectedValue = usData;
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211 if( xError == pdFALSE )
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213 /* Only increment the check variable if no errors have
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215 portENTER_CRITICAL();
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216 xPollingConsumerCount++;
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217 portEXIT_CRITICAL();
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221 /* Next time round we would expect the number to be one higher. */
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226 /* Now the queue is empty we block, allowing the producer to place more
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227 items in the queue. */
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228 vTaskDelay( pollqCONSUMER_DELAY );
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230 } /*lint !e818 Function prototype must conform to API. */
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231 /*-----------------------------------------------------------*/
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233 /* This is called to check that all the created tasks are still running with no errors. */
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234 portBASE_TYPE xAreAltPollingQueuesStillRunning( void )
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236 portBASE_TYPE xReturn;
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238 /* Check both the consumer and producer poll count to check they have both
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239 been changed since out last trip round. We do not need a critical section
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240 around the check variables as this is called from a higher priority than
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241 the other tasks that access the same variables. */
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242 if( ( xPollingConsumerCount == pollqINITIAL_VALUE ) ||
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243 ( xPollingProducerCount == pollqINITIAL_VALUE )
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253 /* Set the check variables back down so we know if they have been
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254 incremented the next time around. */
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255 xPollingConsumerCount = pollqINITIAL_VALUE;
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256 xPollingProducerCount = pollqINITIAL_VALUE;
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