/* FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry. This file is part of the FreeRTOS.org distribution. FreeRTOS.org is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA A special exception to the GPL can be applied should you wish to distribute a combined work that includes FreeRTOS.org, without being obliged to provide the source code for any proprietary components. See the licensing section of http://www.FreeRTOS.org for full details of how and when the exception can be applied. *************************************************************************** *************************************************************************** * * * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation * * * * This is a concise, step by step, 'hands on' guide that describes both * * general multitasking concepts and FreeRTOS specifics. It presents and * * explains numerous examples that are written using the FreeRTOS API. * * Full source code for all the examples is provided in an accompanying * * .zip file. * * * *************************************************************************** *************************************************************************** Please ensure to read the configuration and relevant port sections of the online documentation. http://www.FreeRTOS.org - Documentation, latest information, license and contact details. http://www.SafeRTOS.com - A version that is certified for use in safety critical systems. http://www.OpenRTOS.com - Commercial support, development, porting, licensing and training services. */ /** * This version of flash .c is for use on systems that have limited stack space * and no display facilities. The complete version can be found in the * Demo/Common/Full directory. * * Three tasks are created, each of which flash an LED at a different rate. The first * LED flashes every 200ms, the second every 400ms, the third every 600ms. * * The LED flash tasks provide instant visual feedback. They show that the scheduler * is still operational. * */ #include /* Scheduler include files. */ #include "FreeRTOS.h" #include "task.h" /* Demo program include files. */ #include "partest.h" #include "flash.h" #define ledSTACK_SIZE configMINIMAL_STACK_SIZE #define ledNUMBER_OF_LEDS ( 3 ) #define ledFLASH_RATE_BASE ( ( portTickType ) 333 ) /* Variable used by the created tasks to calculate the LED number to use, and the rate at which they should flash the LED. */ static volatile unsigned portBASE_TYPE uxFlashTaskNumber = 0; /* The task that is created three times. */ static portTASK_FUNCTION_PROTO( vLEDFlashTask, pvParameters ); /*-----------------------------------------------------------*/ void vStartLEDFlashTasks( unsigned portBASE_TYPE uxPriority ) { signed portBASE_TYPE xLEDTask; /* Create the three tasks. */ for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask ) { /* Spawn the task. */ xTaskCreate( vLEDFlashTask, ( signed portCHAR * ) "LEDx", ledSTACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL ); } } /*-----------------------------------------------------------*/ static portTASK_FUNCTION( vLEDFlashTask, pvParameters ) { portTickType xFlashRate, xLastFlashTime; unsigned portBASE_TYPE uxLED; /* The parameters are not used. */ ( void ) pvParameters; /* Calculate the LED and flash rate. */ portENTER_CRITICAL(); { /* See which of the eight LED's we should use. */ uxLED = uxFlashTaskNumber; /* Update so the next task uses the next LED. */ uxFlashTaskNumber++; } portEXIT_CRITICAL(); xFlashRate = ledFLASH_RATE_BASE + ( ledFLASH_RATE_BASE * ( portTickType ) uxLED ); xFlashRate /= portTICK_RATE_MS; /* We will turn the LED on and off again in the delay period, so each delay is only half the total period. */ xFlashRate /= ( portTickType ) 2; /* We need to initialise xLastFlashTime prior to the first call to vTaskDelayUntil(). */ xLastFlashTime = xTaskGetTickCount(); for(;;) { /* Delay for half the flash period then turn the LED on. */ vTaskDelayUntil( &xLastFlashTime, xFlashRate ); vParTestToggleLED( uxLED ); /* Delay for half the flash period then turn the LED off. */ vTaskDelayUntil( &xLastFlashTime, xFlashRate ); vParTestToggleLED( uxLED ); } } /*lint !e715 !e818 !e830 Function definition must be standard for task creation. */