/* | |
FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* If you are: * | |
* * | |
* + New to FreeRTOS, * | |
* + Wanting to learn FreeRTOS or multitasking in general quickly * | |
* + Looking for basic training, * | |
* + Wanting to improve your FreeRTOS skills and productivity * | |
* * | |
* then take a look at the FreeRTOS books - available as PDF or paperback * | |
* * | |
* "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
* http://www.FreeRTOS.org/Documentation * | |
* * | |
* A pdf reference manual is also available. Both are usually delivered * | |
* to your inbox within 20 minutes to two hours when purchased between 8am * | |
* and 8pm GMT (although please allow up to 24 hours in case of * | |
* exceptional circumstances). Thank you for your support! * | |
* * | |
*************************************************************************** | |
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 exception 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 kernel. | |
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: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
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 ); | |
} | |
/*-----------------------------------------------------------*/ |