int4._c

这个程序是用atmega128芯片实现外部中断的一个例子

#include<iom128v.h>
#define uchar unsigned char 
#define uint unsigned int 

void ext_int0_isr(void)
{
  uchar aa=1;
  while(aa)       //判断端口是否恢复高电平，有延时抗干扰
  {
  aa=!(PINE&(1<<4));
  if(aa==0)
    {
	key+=1;
	aa=!(PINE&(1<<4));
	}
  }
}

//数码管译码函数
uchar encoder(uchar key)
{
uchar num;
switch(key)
{
  case 1:
  num=0x79;break;
  case 2:
  num=0x24;break;
  case 4:
  num=0x30;break;
  case 8:
  num=0x19;break;
  case 16:
  num=0x12;break;
  case 32:
  num=0x02;break;
  case 64:
  num=0x78;break;
  case 128:
  num=0x00;break;
}
  return(num);
}

//主函数
main()
{uchar key=0;
DDRA=0xff;
DDRE=0x00;
PORTE=0xff;
SREG=0x80;    //开全局中断
EIMSK=0x10;   //开外部中断int_4,对应按键K5
EICRB=0xf0;


DDRA=0xff;
PORTA=0xff;
DDRC=0xff;
PORTC=0xff;
DDRE=0x00;
PORTE=0xff;
DDRF=0xf8;
while(1);

}