2 FreeRTOS.org V5.1.1 - Copyright (C) 2003-2008 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 ***************************************************************************
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29 * SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
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30 * and even write all or part of your application on your behalf. *
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31 * See http://www.OpenRTOS.com for details of the services we provide to *
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32 * expedite your project. *
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34 ***************************************************************************
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35 ***************************************************************************
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37 Please ensure to read the configuration and relevant port sections of the
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38 online documentation.
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40 http://www.FreeRTOS.org - Documentation, latest information, license and
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43 http://www.SafeRTOS.com - A version that is certified for use in safety
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46 http://www.OpenRTOS.com - Commercial support, development, porting,
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47 licensing and training services.
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51 * This version of flash .c is for use on systems that have limited stack space
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52 * and no display facilities. The complete version can be found in the
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53 * Demo/Common/Full directory.
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55 * Three tasks are created, each of which flash an LED at a different rate. The first
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56 * LED flashes every 200ms, the second every 400ms, the third every 600ms.
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58 * The LED flash tasks provide instant visual feedback. They show that the scheduler
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59 * is still operational.
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66 /* Scheduler include files. */
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67 #include "FreeRTOS.h"
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70 /* Demo program include files. */
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71 #include "partest.h"
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74 #define ledSTACK_SIZE configMINIMAL_STACK_SIZE
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75 #define ledNUMBER_OF_LEDS ( 3 )
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76 #define ledFLASH_RATE_BASE ( ( portTickType ) 333 )
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78 /* Variable used by the created tasks to calculate the LED number to use, and
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79 the rate at which they should flash the LED. */
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80 static volatile unsigned portBASE_TYPE uxFlashTaskNumber = 0;
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82 /* The task that is created three times. */
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83 static portTASK_FUNCTION_PROTO( vLEDFlashTask, pvParameters );
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85 static xTaskHandle xFlashTaskHandles[ ledNUMBER_OF_LEDS ] = { 0 };
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87 /*-----------------------------------------------------------*/
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89 void vStartLEDFlashTasks( unsigned portBASE_TYPE uxPriority )
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91 signed portBASE_TYPE xLEDTask;
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93 /* Create the three tasks. */
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94 for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask )
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96 /* Spawn the task. */
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97 xTaskCreate( vLEDFlashTask, ( signed portCHAR * ) "LEDx", ledSTACK_SIZE, NULL, uxPriority, &( xFlashTaskHandles[ xLEDTask ] ) );
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100 /*-----------------------------------------------------------*/
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102 void vSuspendFlashTasks( short sSuspendTasks )
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104 signed portBASE_TYPE xLEDTask;
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106 for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask )
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108 if( xFlashTaskHandles[ xLEDTask ] != NULL )
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110 if( sSuspendTasks == pdTRUE )
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112 vTaskSuspend( xFlashTaskHandles[ xLEDTask ] );
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116 vTaskResume( xFlashTaskHandles[ xLEDTask ] );
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121 /*-----------------------------------------------------------*/
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123 static portTASK_FUNCTION( vLEDFlashTask, pvParameters )
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125 portTickType xFlashRate, xLastFlashTime;
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126 unsigned portBASE_TYPE uxLED;
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128 /* The parameters are not used. */
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129 ( void ) pvParameters;
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131 /* Calculate the LED and flash rate. */
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132 portENTER_CRITICAL();
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134 /* See which of the eight LED's we should use. */
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135 uxLED = uxFlashTaskNumber;
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137 /* Update so the next task uses the next LED. */
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138 uxFlashTaskNumber++;
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140 portEXIT_CRITICAL();
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142 xFlashRate = ledFLASH_RATE_BASE + ( ledFLASH_RATE_BASE * ( portTickType ) uxLED );
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143 xFlashRate /= portTICK_RATE_MS;
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145 /* We will turn the LED on and off again in the delay period, so each
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146 delay is only half the total period. */
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147 xFlashRate /= ( portTickType ) 2;
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149 /* We need to initialise xLastFlashTime prior to the first call to
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150 vTaskDelayUntil(). */
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151 xLastFlashTime = xTaskGetTickCount();
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155 /* Delay for half the flash period then turn the LED on. */
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156 vTaskDelayUntil( &xLastFlashTime, xFlashRate );
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157 vParTestToggleLED( uxLED );
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159 /* Delay for half the flash period then turn the LED off. */
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160 vTaskDelayUntil( &xLastFlashTime, xFlashRate );
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161 vParTestToggleLED( uxLED );
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163 } /*lint !e715 !e818 !e830 Function definition must be standard for task creation. */
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