2 FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to distribute
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28 >>! a combined work that includes FreeRTOS without being obliged to provide
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29 >>! the source code for proprietary components outside of the FreeRTOS
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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67 * This is a version of PollQ.c that uses the alternative (Alt) API.
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69 * Creates two tasks that communicate over a single queue. One task acts as a
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70 * producer, the other a consumer.
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72 * The producer loops for three iteration, posting an incrementing number onto the
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73 * queue each cycle. It then delays for a fixed period before doing exactly the
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76 * The consumer loops emptying the queue. Each item removed from the queue is
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77 * checked to ensure it contains the expected value. When the queue is empty it
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78 * blocks for a fixed period, then does the same again.
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80 * All queue access is performed without blocking. The consumer completely empties
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81 * the queue each time it runs so the producer should never find the queue full.
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83 * An error is flagged if the consumer obtains an unexpected value or the producer
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84 * find the queue is full.
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90 + Delay periods are now specified using variables and constants of
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91 portTickType rather than unsigned long.
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96 /* Scheduler include files. */
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97 #include "FreeRTOS.h"
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101 /* Demo program include files. */
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102 #include "AltPollQ.h"
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104 #define pollqSTACK_SIZE configMINIMAL_STACK_SIZE
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105 #define pollqQUEUE_SIZE ( 10 )
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106 #define pollqPRODUCER_DELAY ( ( portTickType ) 200 / portTICK_RATE_MS )
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107 #define pollqCONSUMER_DELAY ( pollqPRODUCER_DELAY - ( portTickType ) ( 20 / portTICK_RATE_MS ) )
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108 #define pollqNO_DELAY ( ( portTickType ) 0 )
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109 #define pollqVALUES_TO_PRODUCE ( ( signed portBASE_TYPE ) 3 )
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110 #define pollqINITIAL_VALUE ( ( signed portBASE_TYPE ) 0 )
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112 /* The task that posts the incrementing number onto the queue. */
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113 static portTASK_FUNCTION_PROTO( vPolledQueueProducer, pvParameters );
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115 /* The task that empties the queue. */
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116 static portTASK_FUNCTION_PROTO( vPolledQueueConsumer, pvParameters );
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118 /* Variables that are used to check that the tasks are still running with no
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120 static volatile signed portBASE_TYPE xPollingConsumerCount = pollqINITIAL_VALUE, xPollingProducerCount = pollqINITIAL_VALUE;
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122 /*-----------------------------------------------------------*/
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124 void vStartAltPolledQueueTasks( unsigned portBASE_TYPE uxPriority )
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126 static xQueueHandle xPolledQueue;
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128 /* Create the queue used by the producer and consumer. */
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129 xPolledQueue = xQueueCreate( pollqQUEUE_SIZE, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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131 /* vQueueAddToRegistry() adds the queue to the queue registry, if one is
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132 in use. The queue registry is provided as a means for kernel aware
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133 debuggers to locate queues and has no purpose if a kernel aware debugger
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134 is not being used. The call to vQueueAddToRegistry() will be removed
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135 by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is
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136 defined to be less than 1. */
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137 vQueueAddToRegistry( xPolledQueue, "AltPollQueue" );
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140 /* Spawn the producer and consumer. */
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141 xTaskCreate( vPolledQueueConsumer, "QConsNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( xTaskHandle * ) NULL );
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142 xTaskCreate( vPolledQueueProducer, "QProdNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( xTaskHandle * ) NULL );
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144 /*-----------------------------------------------------------*/
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146 static portTASK_FUNCTION( vPolledQueueProducer, pvParameters )
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148 unsigned short usValue = ( unsigned short ) 0;
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149 signed portBASE_TYPE xError = pdFALSE, xLoop;
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152 void vPrintDisplayMessage( const char * const * ppcMessageToSend );
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154 const char * const pcTaskStartMsg = "Alt polling queue producer task started.\r\n";
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156 /* Queue a message for printing to say the task has started. */
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157 vPrintDisplayMessage( &pcTaskStartMsg );
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162 for( xLoop = 0; xLoop < pollqVALUES_TO_PRODUCE; xLoop++ )
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164 /* Send an incrementing number on the queue without blocking. */
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165 if( xQueueAltSendToBack( *( ( xQueueHandle * ) pvParameters ), ( void * ) &usValue, pollqNO_DELAY ) != pdPASS )
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167 /* We should never find the queue full so if we get here there
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168 has been an error. */
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173 if( xError == pdFALSE )
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175 /* If an error has ever been recorded we stop incrementing the
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177 portENTER_CRITICAL();
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178 xPollingProducerCount++;
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179 portEXIT_CRITICAL();
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182 /* Update the value we are going to post next time around. */
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187 /* Wait before we start posting again to ensure the consumer runs and
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188 empties the queue. */
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189 vTaskDelay( pollqPRODUCER_DELAY );
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191 } /*lint !e818 Function prototype must conform to API. */
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192 /*-----------------------------------------------------------*/
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194 static portTASK_FUNCTION( vPolledQueueConsumer, pvParameters )
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196 unsigned short usData, usExpectedValue = ( unsigned short ) 0;
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197 signed portBASE_TYPE xError = pdFALSE;
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200 void vPrintDisplayMessage( const char * const * ppcMessageToSend );
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202 const char * const pcTaskStartMsg = "Alt blocking queue consumer task started.\r\n";
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204 /* Queue a message for printing to say the task has started. */
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205 vPrintDisplayMessage( &pcTaskStartMsg );
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210 /* Loop until the queue is empty. */
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211 while( uxQueueMessagesWaiting( *( ( xQueueHandle * ) pvParameters ) ) )
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213 if( xQueueAltReceive( *( ( xQueueHandle * ) pvParameters ), &usData, pollqNO_DELAY ) == pdPASS )
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215 if( usData != usExpectedValue )
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217 /* This is not what we expected to receive so an error has
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221 /* Catch-up to the value we received so our next expected
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222 value should again be correct. */
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223 usExpectedValue = usData;
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227 if( xError == pdFALSE )
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229 /* Only increment the check variable if no errors have
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231 portENTER_CRITICAL();
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232 xPollingConsumerCount++;
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233 portEXIT_CRITICAL();
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237 /* Next time round we would expect the number to be one higher. */
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242 /* Now the queue is empty we block, allowing the producer to place more
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243 items in the queue. */
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244 vTaskDelay( pollqCONSUMER_DELAY );
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246 } /*lint !e818 Function prototype must conform to API. */
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247 /*-----------------------------------------------------------*/
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249 /* This is called to check that all the created tasks are still running with no errors. */
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250 portBASE_TYPE xAreAltPollingQueuesStillRunning( void )
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252 portBASE_TYPE xReturn;
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254 /* Check both the consumer and producer poll count to check they have both
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255 been changed since out last trip round. We do not need a critical section
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256 around the check variables as this is called from a higher priority than
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257 the other tasks that access the same variables. */
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258 if( ( xPollingConsumerCount == pollqINITIAL_VALUE ) ||
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259 ( xPollingProducerCount == pollqINITIAL_VALUE )
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269 /* Set the check variables back down so we know if they have been
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270 incremented the next time around. */
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271 xPollingConsumerCount = pollqINITIAL_VALUE;
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272 xPollingProducerCount = pollqINITIAL_VALUE;
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