ex_int0.c

学习C51时写的中断程序,提供给刚学单片机程序的朋友参考

//外部中断实验一
//功能：按键时产生一次外部中断（小灯闪烁三次）
#include <reg51.h>
unsigned char data buff_time;
unsigned char data wei;

void Delay() //the function of delay 
{  unsigned int i;
  for (i=0; i<25000; i++) ;}

void spark() //the function of sparking the lights for once
{Delay();
P1=0x00;
Delay();
P1=0xff;
}

void main() 
{ 
IE=0;
IP=0X01;
TMOD=0x01;   //set the timer's mode
  TH0=(65536-5000)/256; //fill the timer0's higher register 
  TL0=(65536-5000)%256; //fill the timer0's lower register
  IE=0x83;   //EA=1,IT0=1
  TR0=1;  //start the timer for scanning the key
while(1){}//empty loop  
}


void EXInt() interrupt 0 using 2  //external interupt for 3 times spark 
{ 
EX0=0;
spark();
spark();
spark();
EX0=1;
}


void T0Int() interrupt 1 // timer0 interupt scan for the key 
{
 TH0=(65536-5000)/256; //fill the timer0's higher register 
 TL0=(65536-5000)%256; //fill the timer0's lower register 
 buff_time--;
 wei=buff_time%6; 
 if (wei==5)
 {P0=P0&0xfe;}
else if (wei==4)
 {P0=P0&0xfd;}
else if (wei==3)
 {P0=P0&0xfb;}
else if (wei==2)
 {P0=P0&0xf7;}
else if (wei==1)
 {P0=P0&0xef;}
else if (wei==0)
 {P0=P0&0xdf;}
}