#include<reg52.h>
     #include<absacc.h>
     #define      Z8279    XBYTE[0x8FFF] //定義外部命令口
     #define      D8279    XBYTE[0x8FFE] //定義外部數(shù)據(jù)口
     #define      LEDWR0   0x90    //寫端口命令
#define uchar unsigned char
   
     void view8279(void);
uchar   hour1=0,hour2=0,min1=0,min2=0,sec1=0,sec2=0,num_20; //時分秒的十位和個位，初值為零
     uchar led[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x77,0x7C,0x39,0x5E,0x79,0x71};//定義0到F的鍵碼
   
     void main(void)
     {
      TMOD=0x01;
      TH0=0x3c;
      TL0=0xb0;
      IE=0x82;
      TR0=1;
      num_20=20;
      while(1)
      {}
     }
   
     void shizhong(void) interrupt 1
     {          //7                 
      TH0=0x3c;
      TL0=0xb0;
      num_20--;
      if(num_20!=0) return;
    
      if(sec1==5 && sec2==9)
      {          //05
    sec1=0;
    sec2=0;
       if(min1==5 && min2==9)
       {         //03
     min1=0;
     min2=0;
        if(hour1==5 && hour2==9)
        {        //01
         hour1=0;
         hour2=0;
     }        //01
         else if(hour2==9)
         {       //02
          hour1++;
          hour2=0;
         }       //02
         else hour2++;
        }        //03
        else if(min2==9)
        {        //04
         min1++;
         min2=0;
        }        //04
         else min2++;
       }
            //05
       else if(sec2==9)
       {         //06
        sec1++;
        sec2=0;
       }         //06
       else sec2++;
   
    
      view8279();
      num_20=20;         //7
     }
   
     void view8279(void)
     {  
      if (1)    //在正常顯示情況下顯示各位數(shù)字
      {
          Z8279=LEDWR0;
            D8279=led[sec2];
            D8279=led[sec1];
      D8279=0x40;     
            D8279=led[min2];
            D8279=led[min1];
            D8279=0x40;
            D8279=led[hour2];
            D8279=led[hour1];
      }
     }