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FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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This file is part of the FreeRTOS distribution.
FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
>>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
distribute a combined work that includes FreeRTOS without being obliged to
provide the source code for proprietary components outside of the FreeRTOS
FreeRTOS 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
and the FreeRTOS license exception along with FreeRTOS; if not it can be
viewed here: and also obtained by
writing to Real Time Engineers Ltd., contact details for whom are available
on the FreeRTOS WEB site.
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* Having a problem? Start by reading the FAQ "My application does *
* not run, what could be wrong?" *
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*************************************************************************** - Documentation, books, training, latest versions,
license and Real Time Engineers Ltd. contact details. - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, and our new
fully thread aware and reentrant UDP/IP stack. - Real Time Engineers ltd license FreeRTOS to High
Integrity Systems, who sell the code with commercial support,
indemnification and middleware, under the OpenRTOS brand. - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
* 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 <stdlib.h>
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
/* Demo program include files. */
#include "partest.h"
#include "flash.h"
#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 char * ) "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. */
/* See which of the eight LED's we should use. */
uxLED = uxFlashTaskNumber;
/* Update so the next task uses the next LED. */
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();
/* 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. */