2 FreeRTOS V7.0.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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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 modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or 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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55 * This version of flash .c is for use on systems that have limited stack space
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56 * and no display facilities. The complete version can be found in the
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57 * Demo/Common/Full directory.
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59 * Three tasks are created, each of which flash an LED at a different rate. The first
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60 * LED flashes every 200ms, the second every 400ms, the third every 600ms.
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62 * The LED flash tasks provide instant visual feedback. They show that the scheduler
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63 * is still operational.
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70 /* Scheduler include files. */
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71 #include "FreeRTOS.h"
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74 /* Demo program include files. */
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75 #include "partest.h"
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78 #define ledSTACK_SIZE configMINIMAL_STACK_SIZE
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79 #define ledNUMBER_OF_LEDS ( 3 )
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80 #define ledFLASH_RATE_BASE ( ( portTickType ) 333 )
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82 /* Variable used by the created tasks to calculate the LED number to use, and
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83 the rate at which they should flash the LED. */
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84 static volatile unsigned portBASE_TYPE uxFlashTaskNumber = 0;
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86 /* The task that is created three times. */
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87 static portTASK_FUNCTION_PROTO( vLEDFlashTask, pvParameters );
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89 /*-----------------------------------------------------------*/
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91 void vStartLEDFlashTasks( unsigned portBASE_TYPE uxPriority )
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93 signed portBASE_TYPE xLEDTask;
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95 /* Create the three tasks. */
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96 for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask )
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98 /* Spawn the task. */
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99 xTaskCreate( vLEDFlashTask, ( signed char * ) "LEDx", ledSTACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL );
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102 /*-----------------------------------------------------------*/
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104 static portTASK_FUNCTION( vLEDFlashTask, pvParameters )
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106 portTickType xFlashRate, xLastFlashTime;
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107 unsigned portBASE_TYPE uxLED;
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109 /* The parameters are not used. */
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110 ( void ) pvParameters;
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112 /* Calculate the LED and flash rate. */
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113 portENTER_CRITICAL();
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115 /* See which of the eight LED's we should use. */
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116 uxLED = uxFlashTaskNumber;
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118 /* Update so the next task uses the next LED. */
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119 uxFlashTaskNumber++;
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121 portEXIT_CRITICAL();
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123 xFlashRate = ledFLASH_RATE_BASE + ( ledFLASH_RATE_BASE * ( portTickType ) uxLED );
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124 xFlashRate /= portTICK_RATE_MS;
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126 /* We will turn the LED on and off again in the delay period, so each
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127 delay is only half the total period. */
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128 xFlashRate /= ( portTickType ) 2;
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130 /* We need to initialise xLastFlashTime prior to the first call to
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131 vTaskDelayUntil(). */
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132 xLastFlashTime = xTaskGetTickCount();
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136 /* Delay for half the flash period then turn the LED on. */
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137 vTaskDelayUntil( &xLastFlashTime, xFlashRate );
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138 vParTestToggleLED( uxLED );
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140 /* Delay for half the flash period then turn the LED off. */
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141 vTaskDelayUntil( &xLastFlashTime, xFlashRate );
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142 vParTestToggleLED( uxLED );
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144 } /*lint !e715 !e818 !e830 Function definition must be standard for task creation. */
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