STC12C5A单片机外部中断问题

只看该作者 · 2013-10-7 10:37

想用外部中断下降沿检测一个光强变化，结果现在写的程序触发一次下降沿进两次中断，求高手帮忙看一下为什么？红色我是认为可能出错的地方
初始化程序：
#include <stc12c5a60s2.h>
#include<lcd1602_zixie.h>
#define uchar unsigned char
#define uint unsigned int
const int BOCHANG=560;
const float LONG;
const double E=5215.1261       ;
float ZHESHELV=1.35,YAQIANG=12.03;
sbit  key1 = P1^0;
sbit  key2 = P1^1;
sbit  key3 = P3^7;
unsigned char  num=0;
uchar time_num=0;
void delay_ms(uint time)                                                       //延时函数延时time毫秒
{
      uint i,j;
      for(i = 0;i < time;i ++)
            for(j = 0;j < 930;j ++);
}
void main()
{

      Init();//液晶初始化
      EA=1;
      IT0=0;
      ET0=1;
      TMOD=0X01;//定时器0以方式1计数
   TL0=0XB0;
      TH0=0X3C;
      while(1)
      {
            if(key1==0)
            {
                     delay_ms(5);
                     write_com(0X01);                                     //清屏
                     num=0;
                     write_string("Start count num",0x80);
                     EX0=1;
            }
/*             if(key2==0)
            {
                     write_com(0X01);                                     //清屏
                     delay_ms(5);
                     EX0=0;
                     write_string("Result of num",0x80);
                     if((num%2)==1)
                              num=(num+1)/2;
                     else
                              num=num/2;
                     write_num(num,0xc0);
            } */
            if(key3==0)       //复位键
            {
                     write_com(0X01);                                     //清屏
                     EX0=0;
                     num=0;
                     time_num=0;
            }
      }

}
void time0() interrupt 1
{
      TR0=0;
      TL0=0XB0;
      TH0=0X3C;
      if(time_num<20)
      {
            time_num++;
            TR0=1;
      }
      else
      {
               time_num=0;
            EX0=1;//开外部中断0
            TR0=0;
//             num--;
      }

}
void exint0() interrupt 0
{
      EX0=0;
      num++;
      write_num(num,0xc0);
      TR0=1;//开定时器0
}