程序代码：

#include <REGX51.H>
#include <intrins.h>
void delay(unsigned char _ms)        //@11.0592MHz
{
    unsigned char i, j;
    while(_ms--)
      {
    _nop_();
    i = 2;
    j = 199;
    do
    {
        while (--j);
    } while (--i);
    }
}                        %单位延时
sbit wei=P2^7;
sbit dua=P2^6;
unsigned char i=0;
unsigned int code a[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
void main()
{
    EA=1；%打开总开关
    EX0=1;%打开外部中断0
    IT0=1;%下降沿触发
    while(1){
        P0=0xfe;
        wei=0;%选择第一个数码管
        wei=1;%关闭位选
        dua=1;%打开段选
        P0=a[i];%数码管显示的值
    }
}
void xint0() interrupt 0 using 1    %中断函数
{
    i=i+1;
    if(i==15)
        i=0;
}