2 FreeRTOS.org V4.2.0 - 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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30 ***************************************************************************
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34 * This version of flash .c is for use on systems that have limited stack space
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35 * and no display facilities. The complete version can be found in the
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36 * Demo/Common/Full directory.
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38 * Three tasks are created, each of which flash an LED at a different rate. The first
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39 * LED flashes every 200ms, the second every 400ms, the third every 600ms.
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41 * The LED flash tasks provide instant visual feedback. They show that the scheduler
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42 * is still operational.
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44 * The PC port uses the standard parallel port for outputs, the Flashlite 186 port
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45 * uses IO port F and the AVR port port B.
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52 + Delay periods are now specified using variables and constants of
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53 portTickType rather than unsigned portLONG.
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57 + Calls to vTaskDelay() have been replaced with vTaskDelayUntil().
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63 /* Scheduler include files. */
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64 #include "FreeRTOS.h"
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67 /* Demo program include files. */
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68 #include "partest.h"
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71 #define ledSTACK_SIZE configMINIMAL_STACK_SIZE
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72 #define ledNUMBER_OF_LEDS ( 3 )
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73 #define ledFLASH_RATE_BASE ( ( portTickType ) 333 )
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75 /* Variable used by the created tasks to calculate the LED number to use, and
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76 the rate at which they should flash the LED. */
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77 static volatile unsigned portBASE_TYPE uxFlashTaskNumber = 0;
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79 /* The task that is created three times. */
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80 static portTASK_FUNCTION_PROTO( vLEDFlashTask, pvParameters );
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82 /*-----------------------------------------------------------*/
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84 void vStartLEDFlashTasks( unsigned portBASE_TYPE uxPriority )
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86 signed portBASE_TYPE xLEDTask;
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88 /* Create the three tasks. */
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89 for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask )
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91 /* Spawn the task. */
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92 xTaskCreate( vLEDFlashTask, ( const signed portCHAR * const ) "LEDx", ledSTACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL );
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95 /*-----------------------------------------------------------*/
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97 static portTASK_FUNCTION( vLEDFlashTask, pvParameters )
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99 portTickType xFlashRate, xLastFlashTime;
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100 unsigned portBASE_TYPE uxLED;
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102 /* The parameters are not used. */
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103 ( void ) pvParameters;
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105 /* Calculate the LED and flash rate. */
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106 portENTER_CRITICAL();
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108 /* See which of the eight LED's we should use. */
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109 uxLED = uxFlashTaskNumber;
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111 /* Update so the next task uses the next LED. */
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112 uxFlashTaskNumber++;
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114 portEXIT_CRITICAL();
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116 xFlashRate = ledFLASH_RATE_BASE + ( ledFLASH_RATE_BASE * ( portTickType ) uxLED );
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117 xFlashRate /= portTICK_RATE_MS;
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119 /* We will turn the LED on and off again in the delay period, so each
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120 delay is only half the total period. */
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121 xFlashRate /= ( portTickType ) 2;
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123 /* We need to initialise xLastFlashTime prior to the first call to
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124 vTaskDelayUntil(). */
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125 xLastFlashTime = xTaskGetTickCount();
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129 /* Delay for half the flash period then turn the LED on. */
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130 vTaskDelayUntil( &xLastFlashTime, xFlashRate );
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131 vParTestToggleLED( uxLED );
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133 /* Delay for half the flash period then turn the LED off. */
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134 vTaskDelayUntil( &xLastFlashTime, xFlashRate );
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135 vParTestToggleLED( uxLED );
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137 } /*lint !e715 !e818 !e830 Function definition must be standard for task creation. */
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