/*
    FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
	

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS tutorial books are available in pdf and paperback.        *
     *    Complete, revised, and edited pdf reference manuals are also       *
     *    available.                                                         *
     *                                                                       *
     *    Purchasing FreeRTOS documentation will not only help you, by       *
     *    ensuring you get running as quickly as possible and with an        *
     *    in-depth knowledge of how to use FreeRTOS, it will also help       *
     *    the FreeRTOS project to continue with its mission of providing     *
     *    professional grade, cross platform, de facto standard solutions    *
     *    for microcontrollers - completely free of charge!                  *
     *                                                                       *
     *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
     *                                                                       *
     *    Thank you for using FreeRTOS, and 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 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
    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!
    
    ***************************************************************************
     *                                                                       *
     *    Having a problem?  Start by reading the FAQ "My application does   *
     *    not run, what could be wrong?                                      *
     *                                                                       *
     *    http://www.FreeRTOS.org/FAQHelp.html                               *
     *                                                                       *
    ***************************************************************************

    
    http://www.FreeRTOS.org - Documentation, training, latest information, 
    license and contact details.
    
    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool.

    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell 
    the code with commercial support, indemnification, and middleware, under 
    the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
    provide a safety engineered and independently SIL3 certified version under 
    the SafeRTOS brand: http://www.SafeRTOS.com.
*/

/*
 * 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 );
}
/*-----------------------------------------------------------*/