2 FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 ***************************************************************************
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8 * + New to FreeRTOS, *
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9 * + Wanting to learn FreeRTOS or multitasking in general quickly *
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10 * + Looking for basic training, *
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11 * + Wanting to improve your FreeRTOS skills and productivity *
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13 * then take a look at the FreeRTOS eBook *
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15 * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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16 * http://www.FreeRTOS.org/Documentation *
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18 * A pdf reference manual is also available. Both are usually delivered *
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19 * to your inbox within 20 minutes to two hours when purchased between 8am *
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20 * and 8pm GMT (although please allow up to 24 hours in case of *
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21 * exceptional circumstances). Thank you for your support! *
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23 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 ***NOTE*** The exception to the GPL is included to allow you to distribute
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31 a combined work that includes FreeRTOS without being obliged to provide the
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32 source code for proprietary components outside of the FreeRTOS kernel.
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33 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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34 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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35 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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61 * Instead of the normal single demo application, the PIC18F demo is split
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62 * into several smaller programs of which this is the seventh. This enables the
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63 * demo's to be executed on the RAM limited PIC-devices.
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65 * The Demo7 project is configured for a PIC18F4620 device. Main.c starts 10
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66 * tasks (including the idle task). See the indicated files in the demo/common
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67 * directory for more information.
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69 * demo/common/minimal/flash.c: Creates 3 tasks
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70 * demo/common/minimal/death.c: Creates 1 controltask and
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71 * creates/deletes 4 suicidaltasks
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73 * Main.c also creates a check task. This periodically checks that all the
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74 * other tasks are still running and have not experienced any unexpected
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75 * results. If all the other tasks are executing correctly an LED is flashed
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76 * once every mainCHECK_PERIOD milliseconds. If any of the tasks have not
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77 * executed, or report an error, the frequency of the LED flash will increase
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78 * to mainERROR_FLASH_RATE.
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80 * On entry to main an 'X' is transmitted. Monitoring the serial port using a
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81 * dumb terminal allows for verification that the device is not continuously
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82 * being reset (no more than one 'X' should be transmitted).
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84 * http://www.FreeRTOS.org contains important information on the use of the
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88 /* Scheduler include files. */
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89 #include <FreeRTOS.h>
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92 /* Demo app include files. */
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95 #include "partest.h"
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98 /* The period between executions of the check task before and after an error
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99 has been discovered. If an error has been discovered the check task runs
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100 more frequently - increasing the LED flash rate. */
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101 #define mainNO_ERROR_CHECK_PERIOD ( ( portTickType ) 10000 / portTICK_RATE_MS )
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102 #define mainERROR_CHECK_PERIOD ( ( portTickType ) 1000 / portTICK_RATE_MS )
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103 #define mainCHECK_TASK_LED ( ( unsigned char ) 3 )
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105 /* Priority definitions for some of the tasks. Other tasks just use the idle
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107 #define mainCHECK_TASK_PRIORITY ( tskIDLE_PRIORITY + ( unsigned char ) 2 )
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108 #define mainLED_FLASH_PRIORITY ( tskIDLE_PRIORITY + ( unsigned char ) 2 )
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109 #define mainCREATOR_TASK_PRIORITY ( tskIDLE_PRIORITY + ( unsigned char ) 1 )
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111 /* Constants required for the communications. Only one character is ever
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113 #define mainCOMMS_QUEUE_LENGTH ( ( unsigned char ) 5 )
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114 #define mainNO_BLOCK ( ( portTickType ) 0 )
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115 #define mainBAUD_RATE ( ( unsigned long ) 57600 )
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118 * The task function for the "Check" task.
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120 static portTASK_FUNCTION_PROTO( vErrorChecks, pvParameters );
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123 * Checks the unique counts of other tasks to ensure they are still operational.
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124 * Returns pdTRUE if an error is detected, otherwise pdFALSE.
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126 static char prvCheckOtherTasksAreStillRunning( void );
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128 /*-----------------------------------------------------------*/
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130 /* Creates the tasks, then starts the scheduler. */
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133 /* Initialise the required hardware. */
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134 vParTestInitialise();
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136 /* Send a character so we have some visible feedback of a reset. */
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137 xSerialPortInitMinimal( mainBAUD_RATE, mainCOMMS_QUEUE_LENGTH );
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138 xSerialPutChar( NULL, 'X', mainNO_BLOCK );
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140 /* Start a few of the standard demo tasks found in the demo\common directory. */
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141 vStartLEDFlashTasks( mainLED_FLASH_PRIORITY );
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143 /* Start the check task defined in this file. */
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144 xTaskCreate( vErrorChecks, ( const char * const ) "Check", portMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );
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146 /* This task has to be created last as it keeps account of the number of tasks
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147 it expects to see running. */
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148 vCreateSuicidalTasks( mainCREATOR_TASK_PRIORITY );
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150 /* Start the scheduler. Will never return here. */
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151 vTaskStartScheduler();
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153 while(1) /* This point should never be reached. */
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157 /*-----------------------------------------------------------*/
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159 static portTASK_FUNCTION( vErrorChecks, pvParameters )
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161 portTickType xLastCheckTime;
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162 portTickType xDelayTime = mainNO_ERROR_CHECK_PERIOD;
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163 char cErrorOccurred;
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165 /* We need to initialise xLastCheckTime prior to the first call to
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166 vTaskDelayUntil(). */
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167 xLastCheckTime = xTaskGetTickCount();
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169 /* Cycle for ever, delaying then checking all the other tasks are still
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170 operating without error. */
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173 /* Wait until it is time to check the other tasks again. */
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174 vTaskDelayUntil( &xLastCheckTime, xDelayTime );
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176 /* Check all the other tasks are running, and running without ever
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177 having an error. */
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178 cErrorOccurred = prvCheckOtherTasksAreStillRunning();
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180 /* If an error was detected increase the frequency of the LED flash. */
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181 if( cErrorOccurred == pdTRUE )
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183 xDelayTime = mainERROR_CHECK_PERIOD;
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186 /* Flash the LED for visual feedback. */
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187 vParTestToggleLED( mainCHECK_TASK_LED );
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190 /*-----------------------------------------------------------*/
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192 static char prvCheckOtherTasksAreStillRunning( void )
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194 char cErrorHasOccurred = ( char ) pdFALSE;
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196 if( xIsCreateTaskStillRunning() != pdTRUE )
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198 cErrorHasOccurred = ( char ) pdTRUE;
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201 return cErrorHasOccurred;
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203 /*-----------------------------------------------------------*/
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