setup_ext_int.c

mpc564 时钟中断 时钟中断

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 * Copyright: MOTOROLA, INC. All Rights Reserved.
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/*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
 *  File:  setup_ext_int.c                                       *
 *                                                               *
 *  Setup external interrupts for MPC5xx                         *
 *                                                               *
 *  Last Updated: 02/09/17 14:14                                 *
 *                                                               *
 *=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*/

/*****************************************************************
 *                                                               *
 *  In this example, the ISR simply calls a C function.          *
 *  However, since the C function may be out of range for a PC   *
 *  relative call, we will call it using far absolute addressing.*
 *                                                               *
 *****************************************************************/

#include "m_common.h"
#include "mpc500_util.h"
#include "mpc555.h"

/* save current state of section characteristics */

#pragma push

/* change the .text section to far absolute addressing */

#pragma section code_type ".text" code_mode=far_abs

/* tell the compiler to use the current addressing mode for .text  */
/* for all calls to ext_Int_Handler(), this must be done before    */
/* the first reference or prototype of ext_Int_Handler()           */

void ext_Int_Handler(void);

/* create new code section called .ext_isr */

#pragma section code_type ".ext_isr"

/* use .ext_isr as the default section for code, this must be      */
/* done before the first reference or prototype of external_isr()  */

void external_isr();

/* mods are done, restore the state of the sections, .text will go */
/* back to being PC relative and the default section for all code  */

#pragma pop

#pragma interrupt SRR on

void external_isr()
    {
    ext_Int_Handler();
    }
#pragma interrupt off


/*******************************************************************************************
FUNCTION        : setup_ext_int
PURPOSE         : sets up the MPC5xx to respond to external interrupts
INPUT NOTES     : None
RETURN NOTES	: None
GENERAL NOTES   : Enables the U-interface to pass on interrupts to PowerPC
*******************************************************************************************/

void setup_ext_int (void)
    {

    struct USIU_tag *usiu = &USIU;          /* pointer for USIU */

    usiu->SIMASK.R = SIU_INT_LEVEL2;        /* enable only interrupt level 2 */

  	asm
        {
        mtspr EIE,r7        /* Enable the MSR[EE] and MSR[RI] bits to setup interrupts    */
        mfmsr r3            /* MSR = external interrupts enabled, floating point enabled, */
        ori r3,r3,0x3002    /* machine checks enabled and exception table at 0x00000000   */
		mtmsr r3
        }
    }

/*******************************************************************************************
FUNCTION        : InterruptHandler
PURPOSE         : dummy interrupt handler
INPUT NOTES     :
RETURN NOTES    :
GENERAL NOTES   :
*******************************************************************************************/

void InterruptHandler()
{
	while (1)
	{
	}
}