FreeRTOS/Demo/ARM7_LPC2138_Rowley/mainISR.c

/*
 * FreeRTOS Kernel V10.0.0
 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
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 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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 *
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 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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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 SemaphoreHandle_t 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();
}