2 FreeRTOS.org V4.3.0 - Copyright (C) 2003-2007 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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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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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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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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31 Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
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32 with commercial development and support options.
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33 ***************************************************************************
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37 * This demo application file demonstrates the use of queues to pass data
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38 * between co-routines.
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40 * N represents the number of 'fixed delay' co-routines that are created and
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41 * is set during initialisation.
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43 * N 'fixed delay' co-routines are created that just block for a fixed
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44 * period then post the number of an LED onto a queue. Each such co-routine
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45 * uses a different block period. A single 'flash' co-routine is also created
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46 * that blocks on the same queue, waiting for the number of the next LED it
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47 * should flash. Upon receiving a number it simply toggle the instructed LED
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48 * then blocks on the queue once more. In this manner each LED from LED 0 to
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49 * LED N-1 is caused to flash at a different rate.
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51 * The 'fixed delay' co-routines are created with co-routine priority 0. The
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52 * flash co-routine is created with co-routine priority 1. This means that
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53 * the queue should never contain more than a single item. This is because
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54 * posting to the queue will unblock the 'flash' co-routine, and as this has
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55 * a priority greater than the tasks posting to the queue it is guaranteed to
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56 * have emptied the queue and blocked once again before the queue can contain
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57 * any more date. An error is indicated if an attempt to post data to the
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58 * queue fails - indicating that the queue is already full.
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62 /* Scheduler includes. */
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63 #include "FreeRTOS.h"
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64 #include "croutine.h"
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67 /* Demo application includes. */
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68 #include "partest.h"
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69 #include "crflash.h"
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71 /* The queue should only need to be of length 1. See the description at the
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73 #define crfQUEUE_LENGTH 1
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75 #define crfFIXED_DELAY_PRIORITY 0
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76 #define crfFLASH_PRIORITY 1
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78 /* Only one flash co-routine is created so the index is not significant. */
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79 #define crfFLASH_INDEX 0
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81 /* Don't allow more than crfMAX_FLASH_TASKS 'fixed delay' co-routines to be
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83 #define crfMAX_FLASH_TASKS 8
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85 /* We don't want to block when posting to the queue. */
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86 #define crfPOSTING_BLOCK_TIME 0
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89 * The 'fixed delay' co-routine as described at the top of the file.
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91 static void prvFixedDelayCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
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94 * The 'flash' co-routine as described at the top of the file.
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96 static void prvFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
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98 /* The queue used to pass data between the 'fixed delay' co-routines and the
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99 'flash' co-routine. */
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100 static xQueueHandle xFlashQueue;
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102 /* This will be set to pdFALSE if we detect an error. */
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103 static unsigned portBASE_TYPE uxCoRoutineFlashStatus = pdPASS;
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105 /*-----------------------------------------------------------*/
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108 * See the header file for details.
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110 void vStartFlashCoRoutines( unsigned portBASE_TYPE uxNumberToCreate )
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112 unsigned portBASE_TYPE uxIndex;
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114 if( uxNumberToCreate > crfMAX_FLASH_TASKS )
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116 uxNumberToCreate = crfMAX_FLASH_TASKS;
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119 /* Create the queue used to pass data between the co-routines. */
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120 xFlashQueue = xQueueCreate( crfQUEUE_LENGTH, sizeof( unsigned portBASE_TYPE ) );
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124 /* Create uxNumberToCreate 'fixed delay' co-routines. */
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125 for( uxIndex = 0; uxIndex < uxNumberToCreate; uxIndex++ )
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127 xCoRoutineCreate( prvFixedDelayCoRoutine, crfFIXED_DELAY_PRIORITY, uxIndex );
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130 /* Create the 'flash' co-routine. */
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131 xCoRoutineCreate( prvFlashCoRoutine, crfFLASH_PRIORITY, crfFLASH_INDEX );
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134 /*-----------------------------------------------------------*/
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136 static void prvFixedDelayCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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138 /* Even though this is a co-routine the xResult variable does not need to be
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139 static as we do not need it to maintain its state between blocks. */
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140 signed portBASE_TYPE xResult;
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141 /* The uxIndex parameter of the co-routine function is used as an index into
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142 the xFlashRates array to obtain the delay period to use. */
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143 static const portTickType xFlashRates[ crfMAX_FLASH_TASKS ] = { 150 / portTICK_RATE_MS,
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144 200 / portTICK_RATE_MS,
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145 250 / portTICK_RATE_MS,
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146 300 / portTICK_RATE_MS,
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147 350 / portTICK_RATE_MS,
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148 400 / portTICK_RATE_MS,
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149 450 / portTICK_RATE_MS,
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150 500 / portTICK_RATE_MS };
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152 /* Co-routines MUST start with a call to crSTART. */
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153 crSTART( xHandle );
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157 /* Post our uxIndex value onto the queue. This is used as the LED to
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159 crQUEUE_SEND( xHandle, xFlashQueue, ( void * ) &uxIndex, crfPOSTING_BLOCK_TIME, &xResult );
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161 if( xResult != pdPASS )
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163 /* For the reasons stated at the top of the file we should always
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164 find that we can post to the queue. If we could not then an error
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166 uxCoRoutineFlashStatus = pdFAIL;
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169 crDELAY( xHandle, xFlashRates[ uxIndex ] );
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172 /* Co-routines MUST end with a call to crEND. */
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175 /*-----------------------------------------------------------*/
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177 static void prvFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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179 /* Even though this is a co-routine the variable do not need to be
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180 static as we do not need it to maintain their state between blocks. */
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181 signed portBASE_TYPE xResult;
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182 unsigned portBASE_TYPE uxLEDToFlash;
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184 /* Co-routines MUST start with a call to crSTART. */
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185 crSTART( xHandle );
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190 /* Block to wait for the number of the LED to flash. */
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191 crQUEUE_RECEIVE( xHandle, xFlashQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
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193 if( xResult != pdPASS )
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195 /* We would not expect to wake unless we received something. */
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196 uxCoRoutineFlashStatus = pdFAIL;
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200 /* We received the number of an LED to flash - flash it! */
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201 vParTestToggleLED( uxLEDToFlash );
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205 /* Co-routines MUST end with a call to crEND. */
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208 /*-----------------------------------------------------------*/
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210 portBASE_TYPE xAreFlashCoRoutinesStillRunning( void )
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212 /* Return pdPASS or pdFAIL depending on whether an error has been detected
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214 return uxCoRoutineFlashStatus;
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