原理图

源码

#include<reg52.h>
table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; //共阳极 
unsigned int count,i=0,j; 

void delay (unsigned int ms) //延时函数 
{unsigned char j; while(ms--); 
for(j=0;j<120;j++); } 

void main()
{ count=60; 
TMOD=0x10;
TH1=(65536-50000)/256;
TH1=(65536-50000)/256;
EA=1;
TR1=1;
ET1=1;
P0=0xff; 
P2=0; 
    while(1)
     { P0=0xff; 
        P2=0x01;
        P0=table[count/10]; //十位
        delay(5);
       P0=0xff;
       P0=table[count%10];// 个位
       P2=0x02;
       delay(5);
      if(count==0)
           {TR1=0;}
     }
void Timer1() interrupt 3 
{ TH1=(65536-50000)/256; // 50ms
  TL1=(65536-50000)%256;
  i++;
  if(i>=20) //20次，1000ms=1s
  {count--;
   i=0;}
}