Demo/ARM7_LPC2138_Rowley/mainISR.c

/*
    FreeRTOS V7.0.1 - Copyright (C) 2011 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
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    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
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*/
#include "FreeRTOS.h"
#include "semphr.h"

#define isrCLEAR_EINT_1 2

/*
 * Interrupt routine that simply wakes vButtonHandlerTask on each interrupt 
 * generated by a push of the built in button.  The wrapper takes care of
 * the ISR entry.  This then calls the actual handler function to perform
 * the work.  This work should not be done in the wrapper itself unless
 * you are absolutely sure that no stack space is used.
 */
void vButtonISRWrapper( void ) __attribute__ ((naked));
void vButtonHandler( void ) __attribute__ ((noinline));

void vButtonHandler( void )
{
extern xSemaphoreHandle xButtonSemaphore;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	xSemaphoreGiveFromISR( xButtonSemaphore, &xHigherPriorityTaskWoken );

	if( xHigherPriorityTaskWoken )
	{
		/* We have woken a task.  Calling "yield from ISR" here will ensure
		the interrupt returns to the woken task if it has a priority higher
		than the interrupted task. */
		portYIELD_FROM_ISR();
	}

    EXTINT = isrCLEAR_EINT_1;
    VICVectAddr = 0;
}
/*-----------------------------------------------------------*/

void vButtonISRWrapper( void )
{
	/* Save the context of the interrupted task. */
	portSAVE_CONTEXT();

	/* Call the handler to do the work.  This must be a separate function to
	the wrapper to ensure the correct stack frame is set up. */
	__asm volatile( "bl vButtonHandler" );

	/* Restore the context of whichever task is going to run once the interrupt
	completes. */
	portRESTORE_CONTEXT();
}