2 * FreeRTOS Kernel V10.2.1
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3 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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29 * This demo application file demonstrates the use of queues to pass data
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30 * between co-routines.
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32 * N represents the number of 'fixed delay' co-routines that are created and
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33 * is set during initialisation.
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35 * N 'fixed delay' co-routines are created that just block for a fixed
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36 * period then post the number of an LED onto a queue. Each such co-routine
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37 * uses a different block period. A single 'flash' co-routine is also created
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38 * that blocks on the same queue, waiting for the number of the next LED it
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39 * should flash. Upon receiving a number it simply toggle the instructed LED
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40 * then blocks on the queue once more. In this manner each LED from LED 0 to
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41 * LED N-1 is caused to flash at a different rate.
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43 * The 'fixed delay' co-routines are created with co-routine priority 0. The
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44 * flash co-routine is created with co-routine priority 1. This means that
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45 * the queue should never contain more than a single item. This is because
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46 * posting to the queue will unblock the 'flash' co-routine, and as this has
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47 * a priority greater than the tasks posting to the queue it is guaranteed to
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48 * have emptied the queue and blocked once again before the queue can contain
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49 * any more date. An error is indicated if an attempt to post data to the
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50 * queue fails - indicating that the queue is already full.
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54 /* Scheduler includes. */
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55 #include "FreeRTOS.h"
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56 #include "croutine.h"
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59 /* Demo application includes. */
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60 #include "partest.h"
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61 #include "crflash.h"
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63 /* The queue should only need to be of length 1. See the description at the
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65 #define crfQUEUE_LENGTH 1
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67 #define crfFIXED_DELAY_PRIORITY 0
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68 #define crfFLASH_PRIORITY 1
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70 /* Only one flash co-routine is created so the index is not significant. */
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71 #define crfFLASH_INDEX 0
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73 /* Don't allow more than crfMAX_FLASH_TASKS 'fixed delay' co-routines to be
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75 #define crfMAX_FLASH_TASKS 8
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77 /* We don't want to block when posting to the queue. */
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78 #define crfPOSTING_BLOCK_TIME 0
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81 * The 'fixed delay' co-routine as described at the top of the file.
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83 static void prvFixedDelayCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex );
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86 * The 'flash' co-routine as described at the top of the file.
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88 static void prvFlashCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex );
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90 /* The queue used to pass data between the 'fixed delay' co-routines and the
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91 'flash' co-routine. */
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92 static QueueHandle_t xFlashQueue;
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94 /* This will be set to pdFALSE if we detect an error. */
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95 static BaseType_t xCoRoutineFlashStatus = pdPASS;
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97 /*-----------------------------------------------------------*/
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100 * See the header file for details.
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102 void vStartFlashCoRoutines( UBaseType_t uxNumberToCreate )
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104 UBaseType_t uxIndex;
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106 if( uxNumberToCreate > crfMAX_FLASH_TASKS )
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108 uxNumberToCreate = crfMAX_FLASH_TASKS;
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111 /* Create the queue used to pass data between the co-routines. */
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112 xFlashQueue = xQueueCreate( crfQUEUE_LENGTH, sizeof( UBaseType_t ) );
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116 /* Create uxNumberToCreate 'fixed delay' co-routines. */
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117 for( uxIndex = 0; uxIndex < uxNumberToCreate; uxIndex++ )
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119 xCoRoutineCreate( prvFixedDelayCoRoutine, crfFIXED_DELAY_PRIORITY, uxIndex );
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122 /* Create the 'flash' co-routine. */
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123 xCoRoutineCreate( prvFlashCoRoutine, crfFLASH_PRIORITY, crfFLASH_INDEX );
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126 /*-----------------------------------------------------------*/
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128 static void prvFixedDelayCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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130 /* Even though this is a co-routine the xResult variable does not need to be
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131 static as we do not need it to maintain its state between blocks. */
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132 BaseType_t xResult;
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133 /* The uxIndex parameter of the co-routine function is used as an index into
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134 the xFlashRates array to obtain the delay period to use. */
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135 static const TickType_t xFlashRates[ crfMAX_FLASH_TASKS ] = { 150 / portTICK_PERIOD_MS,
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136 200 / portTICK_PERIOD_MS,
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137 250 / portTICK_PERIOD_MS,
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138 300 / portTICK_PERIOD_MS,
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139 350 / portTICK_PERIOD_MS,
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140 400 / portTICK_PERIOD_MS,
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141 450 / portTICK_PERIOD_MS,
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142 500 / portTICK_PERIOD_MS };
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144 /* Co-routines MUST start with a call to crSTART. */
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145 crSTART( xHandle );
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149 /* Post our uxIndex value onto the queue. This is used as the LED to
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151 crQUEUE_SEND( xHandle, xFlashQueue, ( void * ) &uxIndex, crfPOSTING_BLOCK_TIME, &xResult );
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153 if( xResult != pdPASS )
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155 /* For the reasons stated at the top of the file we should always
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156 find that we can post to the queue. If we could not then an error
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158 xCoRoutineFlashStatus = pdFAIL;
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161 crDELAY( xHandle, xFlashRates[ uxIndex ] );
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164 /* Co-routines MUST end with a call to crEND. */
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167 /*-----------------------------------------------------------*/
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169 static void prvFlashCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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171 /* Even though this is a co-routine the variable do not need to be
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172 static as we do not need it to maintain their state between blocks. */
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173 BaseType_t xResult;
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174 UBaseType_t uxLEDToFlash;
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176 /* Co-routines MUST start with a call to crSTART. */
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177 crSTART( xHandle );
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182 /* Block to wait for the number of the LED to flash. */
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183 crQUEUE_RECEIVE( xHandle, xFlashQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
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185 if( xResult != pdPASS )
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187 /* We would not expect to wake unless we received something. */
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188 xCoRoutineFlashStatus = pdFAIL;
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192 /* We received the number of an LED to flash - flash it! */
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193 vParTestToggleLED( uxLEDToFlash );
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197 /* Co-routines MUST end with a call to crEND. */
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200 /*-----------------------------------------------------------*/
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202 BaseType_t xAreFlashCoRoutinesStillRunning( void )
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204 /* Return pdPASS or pdFAIL depending on whether an error has been detected
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206 return xCoRoutineFlashStatus;
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