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/*
FreeRTOS.org V5.1.1 - 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.
***************************************************************************
***************************************************************************
* *
* SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
* and even write all or part of your application on your behalf. *
* See http://www.OpenRTOS.com for details of the services we provide to *
* expedite your project. *
* *
***************************************************************************
***************************************************************************
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 file defines the button push task and ISR as described at the top of
* main.c. The ISR is called from a wrapper function defined in ButtonISR.s26.
*/
/* Kernel includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
/* The LED output used by the button push task. */
#define butLED1 P7_bit.no7
/* A short delay used for button debouncing. */
#define butDEBOUNCE_DELAY ( 200 / portTICK_RATE_MS )
/* The semaphore used to synchronise the button push task with the interrupt. */
static xSemaphoreHandle xButtonSemaphore;
/*
* The definition of the button task itself. See the comments at the top of
* main.c.
*/
void vButtonTask( void *pvParameters )
{
/* Ensure the semaphore is created before it gets used. */
vSemaphoreCreateBinary( xButtonSemaphore );
for( ;; )
{
/* Block on the semaphore to wait for an interrupt event. The semaphore
is 'given' from vButtonISRHandler() below. Using portMAX_DELAY as the
block time will cause the task to block indefinitely provided
INCLUDE_vTaskSuspend is set to 1 in FreeRTOSConfig.h. */
xSemaphoreTake( xButtonSemaphore, portMAX_DELAY );
/* The button must have been pushed for this line to be executed.
Simply toggle the LED. */
butLED1 = !butLED1;
/* Wait a short time then clear any pending button pushes as a crude
method of debouncing the switch. xSemaphoreTake() uses a block time of
zero this time so it returns immediately rather than waiting for the
interrupt to occur. */
vTaskDelay( butDEBOUNCE_DELAY );
xSemaphoreTake( xButtonSemaphore, 0 );
}
}
/*-----------------------------------------------------------*/
/*
* The C portion of the interrupt handler. Interrupts are triggered by pushing
* the button on the target board. This interrupt can cause a context switch
* so has an assembly file wrapper defined within ButtonISR.s26.
*/
void vButtonISRHandler( void )
{
short sHigherPriorityTaskWoken = pdFALSE;
/* 'Give' the semaphore to unblock the button task. */
xSemaphoreGiveFromISR( xButtonSemaphore, &sHigherPriorityTaskWoken );
/* If giving the semaphore unblocked a task, and the unblocked task has a
priority that is higher than the currently running task, then
sHigherPriorityTaskWoken will have been set to pdTRUE. Passing a pdTRUE
value to portYIELD_FROM_ISR() will cause this interrupt to return directly
to the higher priority unblocked task. */
portYIELD_FROM_ISR( sHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/
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