2 FreeRTOS V9.0.0 - Copyright (C) 2016 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 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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72 * Simple demonstration of the usage of counting semaphore.
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75 /* Scheduler include files. */
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76 #include "FreeRTOS.h"
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80 /* Demo program include files. */
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81 #include "countsem.h"
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83 /* The maximum count value that the semaphore used for the demo can hold. */
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84 #define countMAX_COUNT_VALUE ( 200 )
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86 /* Constants used to indicate whether or not the semaphore should have been
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87 created with its maximum count value, or its minimum count value. These
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88 numbers are used to ensure that the pointers passed in as the task parameters
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90 #define countSTART_AT_MAX_COUNT ( 0xaa )
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91 #define countSTART_AT_ZERO ( 0x55 )
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93 /* Two tasks are created for the test. One uses a semaphore created with its
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94 count value set to the maximum, and one with the count value set to zero. */
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95 #define countNUM_TEST_TASKS ( 2 )
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96 #define countDONT_BLOCK ( 0 )
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98 /*-----------------------------------------------------------*/
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100 /* Flag that will be latched to pdTRUE should any unexpected behaviour be
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101 detected in any of the tasks. */
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102 static volatile BaseType_t xErrorDetected = pdFALSE;
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104 /*-----------------------------------------------------------*/
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107 * The demo task. This simply counts the semaphore up to its maximum value,
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108 * the counts it back down again. The result of each semaphore 'give' and
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109 * 'take' is inspected, with an error being flagged if it is found not to be
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110 * the expected result.
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112 static void prvCountingSemaphoreTask( void *pvParameters );
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115 * Utility function to increment the semaphore count value up from zero to
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116 * countMAX_COUNT_VALUE.
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118 static void prvIncrementSemaphoreCount( SemaphoreHandle_t xSemaphore, UBaseType_t *puxLoopCounter );
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121 * Utility function to decrement the semaphore count value up from
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122 * countMAX_COUNT_VALUE to zero.
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124 static void prvDecrementSemaphoreCount( SemaphoreHandle_t xSemaphore, UBaseType_t *puxLoopCounter );
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126 /*-----------------------------------------------------------*/
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128 /* The structure that is passed into the task as the task parameter. */
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129 typedef struct COUNT_SEM_STRUCT
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131 /* The semaphore to be used for the demo. */
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132 SemaphoreHandle_t xSemaphore;
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134 /* Set to countSTART_AT_MAX_COUNT if the semaphore should be created with
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135 its count value set to its max count value, or countSTART_AT_ZERO if it
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136 should have been created with its count value set to 0. */
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137 UBaseType_t uxExpectedStartCount;
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139 /* Incremented on each cycle of the demo task. Used to detect a stalled
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141 UBaseType_t uxLoopCounter;
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144 /* Two structures are defined, one is passed to each test task. */
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145 static volatile xCountSemStruct xParameters[ countNUM_TEST_TASKS ];
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147 /*-----------------------------------------------------------*/
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149 void vStartCountingSemaphoreTasks( void )
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151 /* Create the semaphores that we are going to use for the test/demo. The
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152 first should be created such that it starts at its maximum count value,
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153 the second should be created such that it starts with a count value of zero. */
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154 xParameters[ 0 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, countMAX_COUNT_VALUE );
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155 xParameters[ 0 ].uxExpectedStartCount = countSTART_AT_MAX_COUNT;
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156 xParameters[ 0 ].uxLoopCounter = 0;
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158 xParameters[ 1 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, 0 );
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159 xParameters[ 1 ].uxExpectedStartCount = 0;
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160 xParameters[ 1 ].uxLoopCounter = 0;
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162 /* Were the semaphores created? */
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163 if( ( xParameters[ 0 ].xSemaphore != NULL ) || ( xParameters[ 1 ].xSemaphore != NULL ) )
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165 /* vQueueAddToRegistry() adds the semaphore to the registry, if one is
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166 in use. The registry is provided as a means for kernel aware
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167 debuggers to locate semaphores and has no purpose if a kernel aware
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168 debugger is not being used. The call to vQueueAddToRegistry() will be
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169 removed by the pre-processor if configQUEUE_REGISTRY_SIZE is not
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170 defined or is defined to be less than 1. */
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171 vQueueAddToRegistry( ( QueueHandle_t ) xParameters[ 0 ].xSemaphore, "Counting_Sem_1" );
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172 vQueueAddToRegistry( ( QueueHandle_t ) xParameters[ 1 ].xSemaphore, "Counting_Sem_2" );
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174 /* Create the demo tasks, passing in the semaphore to use as the parameter. */
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175 xTaskCreate( prvCountingSemaphoreTask, "CNT1", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 0 ] ), tskIDLE_PRIORITY, NULL );
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176 xTaskCreate( prvCountingSemaphoreTask, "CNT2", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 1 ] ), tskIDLE_PRIORITY, NULL );
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179 /*-----------------------------------------------------------*/
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181 static void prvDecrementSemaphoreCount( SemaphoreHandle_t xSemaphore, UBaseType_t *puxLoopCounter )
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185 /* If the semaphore count is at its maximum then we should not be able to
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186 'give' the semaphore. */
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187 if( xSemaphoreGive( xSemaphore ) == pdPASS )
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189 xErrorDetected = pdTRUE;
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192 /* We should be able to 'take' the semaphore countMAX_COUNT_VALUE times. */
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193 for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ )
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195 configASSERT( uxSemaphoreGetCount( xSemaphore ) == ( countMAX_COUNT_VALUE - ux ) );
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197 if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) != pdPASS )
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199 /* We expected to be able to take the semaphore. */
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200 xErrorDetected = pdTRUE;
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203 ( *puxLoopCounter )++;
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206 #if configUSE_PREEMPTION == 0
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210 /* If the semaphore count is zero then we should not be able to 'take'
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212 configASSERT( uxSemaphoreGetCount( xSemaphore ) == 0 );
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213 if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS )
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215 xErrorDetected = pdTRUE;
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218 /*-----------------------------------------------------------*/
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220 static void prvIncrementSemaphoreCount( SemaphoreHandle_t xSemaphore, UBaseType_t *puxLoopCounter )
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224 /* If the semaphore count is zero then we should not be able to 'take'
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226 if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS )
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228 xErrorDetected = pdTRUE;
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231 /* We should be able to 'give' the semaphore countMAX_COUNT_VALUE times. */
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232 for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ )
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234 configASSERT( uxSemaphoreGetCount( xSemaphore ) == ux );
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236 if( xSemaphoreGive( xSemaphore ) != pdPASS )
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238 /* We expected to be able to take the semaphore. */
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239 xErrorDetected = pdTRUE;
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242 ( *puxLoopCounter )++;
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245 #if configUSE_PREEMPTION == 0
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249 /* If the semaphore count is at its maximum then we should not be able to
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250 'give' the semaphore. */
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251 if( xSemaphoreGive( xSemaphore ) == pdPASS )
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253 xErrorDetected = pdTRUE;
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256 /*-----------------------------------------------------------*/
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258 static void prvCountingSemaphoreTask( void *pvParameters )
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260 xCountSemStruct *pxParameter;
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263 void vPrintDisplayMessage( const char * const * ppcMessageToSend );
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265 const char * const pcTaskStartMsg = "Counting semaphore demo started.\r\n";
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267 /* Queue a message for printing to say the task has started. */
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268 vPrintDisplayMessage( &pcTaskStartMsg );
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271 /* The semaphore to be used was passed as the parameter. */
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272 pxParameter = ( xCountSemStruct * ) pvParameters;
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274 /* Did we expect to find the semaphore already at its max count value, or
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276 if( pxParameter->uxExpectedStartCount == countSTART_AT_MAX_COUNT )
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278 prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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281 /* Now we expect the semaphore count to be 0, so this time there is an
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282 error if we can take the semaphore. */
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283 if( xSemaphoreTake( pxParameter->xSemaphore, 0 ) == pdPASS )
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285 xErrorDetected = pdTRUE;
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290 prvIncrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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291 prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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294 /*-----------------------------------------------------------*/
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296 BaseType_t xAreCountingSemaphoreTasksStillRunning( void )
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298 static UBaseType_t uxLastCount0 = 0, uxLastCount1 = 0;
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299 BaseType_t xReturn = pdPASS;
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301 /* Return fail if any 'give' or 'take' did not result in the expected
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303 if( xErrorDetected != pdFALSE )
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308 /* Return fail if either task is not still incrementing its loop counter. */
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309 if( uxLastCount0 == xParameters[ 0 ].uxLoopCounter )
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315 uxLastCount0 = xParameters[ 0 ].uxLoopCounter;
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318 if( uxLastCount1 == xParameters[ 1 ].uxLoopCounter )
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324 uxLastCount1 = xParameters[ 1 ].uxLoopCounter;
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