下面是數碼管部分電路原理圖:

下面是矩陣鍵盤部分的電路原理圖:

c51單片機程序如下:
#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
//數碼管的段碼編碼
uchar table[16] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
uchar seg[4]={0xfe,0xfd,0xfb,0xf7};
uchar shu;
void Delay_1ms(uint i)//1ms延時
{
uchar x,j;
for(j=0;j<i;j++)
for(x=0;x<=148;x++);
}
void keyboard()
{
uchar x,y,i;
for(y=0;y<4;y++)
{
P1=seg[y];
if((P1&0xf0)!=0xf0)
{
Delay_1ms(5);
if((P1&0xf0)!=0xf0)
{
x=P1&0XF0;
x=(x>>4)|0xf0;
for(i=0;i<4;i++)
{
if(x==seg[i])
{
x=i;
shu=4*y+x+1;
}
}
}
}
}
}
void segdisplay(uchar i)
{
P0 = 0; //消隱
P2 = 6; //第7位數碼管顯示
P0 = table[(i / 10)%10]; //在這里取 i 的十位數
Delay_1ms(5); //延時0.5秒后顯示下一個數
P0 = 0; //消隱
P2 = 7; //第8位數碼管顯示
P0 = table[i % 10]; //在這里取 i 的個位數
Delay_1ms(5);
P0=0;
}
void main()
{
shu = 0;
while(1)
{
keyboard();
segdisplay(shu);
}
}