FreeRTOS/Demo/CORTEX_A5_SAMA5D4x_EK_IAR/FreeRTOS_tick_config.c

/*
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    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.

	***************************************************************************
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    >>!   outside of the FreeRTOS kernel.                                   !<<
	***************************************************************************

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*/

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "Task.h"

/* Library includes. */
#include "board.h"

/*
 * The FreeRTOS tick handler.  This function must be installed as the handler
 * for the timer used to generate the tick interrupt.  Note that the interrupt
 * generated by the PIT is shared by other system peripherals, so if the PIT is
 * used for Tick generation then FreeRTOS_Tick_Handler() can only be installed
 * directly as the PIT handler if no other system interrupts need to be
 * serviced.  If system interrupts other than the PIT need to be serviced then
 * install System_Handler() as the PIT interrupt handler in place of
 * FreeRTOS_Tick_Handler() and add additional interrupt processing into the
 * implementation of System_Handler().
 */
extern void FreeRTOS_Tick_Handler( void );
static void System_Handler( void );

/*-----------------------------------------------------------*/

static void System_Handler( void )
{
	/* See the comments above the function prototype in this file. */
	FreeRTOS_Tick_Handler();
}
/*-----------------------------------------------------------*/

/*
 * The application must provide a function that configures a peripheral to
 * create the FreeRTOS tick interrupt, then define configSETUP_TICK_INTERRUPT()
 * in FreeRTOSConfig.h to call the function.  This file contains a function
 * that is suitable for use on the Atmel SAMA5.
 */
void vConfigureTickInterrupt( void )
{
	/* NOTE:  The PIT interrupt is cleared by the configCLEAR_TICK_INTERRUPT()
	macro in FreeRTOSConfig.h. */

	/* Enable the PIT clock. */
	PMC->PMC_PCER0 = 1 << ID_PIT;

	/* Initialize the PIT to the desired frequency - specified in uS. */
	PIT_Init( 1000000UL / configTICK_RATE_HZ, ( BOARD_MCK / 2 ) / 1000000 );

	/* Enable IRQ / select PIT interrupt. */
	PMC->PMC_PCER1 = ( 1 << ( ID_IRQ - 32 ) );
	AIC->AIC_SSR  = ID_PIT;

	/* Ensure interrupt is disabled before setting the mode and installing the
	handler.  The priority of the tick interrupt should always be set to the
	lowest possible. */
	AIC->AIC_IDCR = AIC_IDCR_INTD;
	AIC->AIC_SMR  = AIC_SMR_SRCTYPE_EXT_POSITIVE_EDGE;
	AIC->AIC_SVR = ( uint32_t ) FreeRTOS_Tick_Handler;

	/* Start with the interrupt clear. */
	AIC->AIC_ICCR = AIC_ICCR_INTCLR;

	/* Enable the interrupt in the AIC and peripheral. */
	AIC_EnableIT( ID_PIT );
	PIT_EnableIT();

	/* Enable the peripheral. */
	PIT_Enable();

	/* Prevent compiler warnings in the case where System_Handler() is not used
	as the handler.  See the comments above the System_Handler() function
	prototype at the top of this file. */
	( void ) System_Handler;
}
/*-----------------------------------------------------------*/