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124 lines
5.6 KiB
C
124 lines
5.6 KiB
C
/*
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FreeRTOS V6.0.1 - Copyright (C) 2009 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS eBook *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/*
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* This file defines the button push task and ISR as described at the top of
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* main.c. The ISR is called from a wrapper function defined in ButtonISR.s26.
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*/
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/* Kernel includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "semphr.h"
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/* The LED output used by the button push task. */
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#define butLED1 P7_bit.no7
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/* A short delay used for button debouncing. */
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#define butDEBOUNCE_DELAY ( 200 / portTICK_RATE_MS )
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/* The semaphore used to synchronise the button push task with the interrupt. */
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static xSemaphoreHandle xButtonSemaphore;
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/*
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* The definition of the button task itself. See the comments at the top of
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* main.c.
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*/
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void vButtonTask( void *pvParameters )
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{
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/* Ensure the semaphore is created before it gets used. */
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vSemaphoreCreateBinary( xButtonSemaphore );
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for( ;; )
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{
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/* Block on the semaphore to wait for an interrupt event. The semaphore
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is 'given' from vButtonISRHandler() below. Using portMAX_DELAY as the
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block time will cause the task to block indefinitely provided
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INCLUDE_vTaskSuspend is set to 1 in FreeRTOSConfig.h. */
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xSemaphoreTake( xButtonSemaphore, portMAX_DELAY );
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/* The button must have been pushed for this line to be executed.
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Simply toggle the LED. */
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butLED1 = !butLED1;
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/* Wait a short time then clear any pending button pushes as a crude
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method of debouncing the switch. xSemaphoreTake() uses a block time of
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zero this time so it returns immediately rather than waiting for the
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interrupt to occur. */
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vTaskDelay( butDEBOUNCE_DELAY );
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xSemaphoreTake( xButtonSemaphore, 0 );
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}
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}
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/*-----------------------------------------------------------*/
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/*
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* The C portion of the interrupt handler. Interrupts are triggered by pushing
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* the button on the target board. This interrupt can cause a context switch
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* so has an assembly file wrapper defined within ButtonISR.s26.
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*/
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void vButtonISRHandler( void )
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{
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short sHigherPriorityTaskWoken = pdFALSE;
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/* 'Give' the semaphore to unblock the button task. */
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xSemaphoreGiveFromISR( xButtonSemaphore, &sHigherPriorityTaskWoken );
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/* If giving the semaphore unblocked a task, and the unblocked task has a
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priority that is higher than the currently running task, then
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sHigherPriorityTaskWoken will have been set to pdTRUE. Passing a pdTRUE
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value to portYIELD_FROM_ISR() will cause this interrupt to return directly
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to the higher priority unblocked task. */
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portYIELD_FROM_ISR( sHigherPriorityTaskWoken );
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}
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/*-----------------------------------------------------------*/
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