interrupt.c

用c语言实现的点亮s3c2410开发板的LED灯的程序

#include "interrupt.h"
#include "led.h"


//中断初始化
void init_interrupt()
{
	//关闭中断
	disable_interrupt();
	
	//初始化相关寄存器
	rI_ISPC = 0x3ffffff;
	//active EINT4,5,6,7
	rEXTINTPND = 0xf;
	//IRQ:0 FIQ:1
	rINTMOD = 0;
	//Reserved V I F 0101
	rINTCON = 0x5;
	//service available EINT 4/5/6/7
	rINTMSK = ~(0x4000000 | 0x200000);
	(*(unsigned*)(0xc7fff00 + 0x18))  = (unsigned)(irq_isr);
	//PG的控制寄存器 EINT1~7=11
	rPCONG = 0xffff;
	//enable pull up register
	rPUPG = 0x00;
	//external interrupt control register
	rEXTINT = rEXTINT | 0x22220020;           //中断4567 全部下降沿触发
	//clear register IRQ interrupt service
	rI_ISPC = rI_ISPC | 0x200000;              //EINT4567 clear the pending bit
	rEXTINTPND = 0xf; 
	
	//使能寄存器
	enable_interrupt();         

}

void irq_isr()
{
	disable_interrupt();
	
	led(8, 1);      /* 点亮LED1 */
    delay(1000);    /* 延时 */
    led(9, 1);      /* 点亮LED2 */
    delay(1000);
    led(8, 0);      /* 点亮LED3 */
    delay(1000);
    led(9, 0);      /* 熄灭LED1 */
    delay(1000);

	
	rEXTINTPND = 0xf;		//EXTINT4.5.6.7同时清除；
	rI_ISPC = 0x3ffffff;	//清除中断状态寄存器，[21]为1的时候，清除extint4.5.6.7；
	
	enable_interrupt();
}

//关闭中断
void disable_interrupt()
{
	__asm
	{
		MRS R0,CPSR
		ORR R0,R0,#0x80
		MSR CPSR_c,R0
	}
}
//使能中断
void enable_interrupt()
{
	__asm
	{
		MRS R0,CPSR
		BIC R0,R0,#0x80
		MSR CPSR_c,R0
	}
}