1.代码：
#include <reg52.h>
typedef unsigned char u8;typedef unsigned int u16;sbit seg_sel = P1^4;sbit bit_sel = P1^5;#define DATA P0u8 code seg_tab[]={ 0xc0,0xf9,0xa4,0xb0, 0x99,0x92,0x82,0xf8, 0x80,0x90,0x88,0x83, 0xc6,0xa1,0x86,0x8e };u8 code bit_tab[]={ 0x10,0x20,0x40,0x80, 0x01,0x02,0x04,0x08 };void delay(u16 num){ u16 x,y; for(x=num; x>0; x--) for(y=110; y>0; y--) { ;//延时1ms }}void display_led(u8 which_bit, u8 which_number){ bit_sel = 1;//Q[7..0]=D[7..0] DATA = bit_tab[which_bit]; bit_sel = 0;//BIT[7..0]=0x80 seg_sel = 1;//Q[7..0]=D[7..0] DATA = seg_tab[which_number]; seg_sel = 0; delay(2); }u8 key_scan (void){ u8 temp,temp2; P2 = 0xf0;//让P2输出0xf0 temp = P2;//读入P2的值 if (temp != 0xf0) //当P2读入的值不等于0xf0 { delay(5);//延迟5ms temp = P2;//再读入P2口的值 if (temp != 0xf0)//如果P2读入的值不等于 { //0xf0，就说明有按键按下 temp2 = temp & 0xf0;//保留P2读入值得高四位 P2 = 0x0f;//再让P2口输出0x0f delay(1); temp = P2;//再读入P2口的值 temp2 |= temp;//保留此读入值的低四位 return temp2; } //while(P2!=0x0f); }}u8 encode(u8 cod){ u8 num; switch(cod) { case 0xee: num = 0;break; case 0xde: num = 1;break; case 0xbe: num = 2;break; case 0x7e: num = 3;break; case 0xed: num = 4;break; case 0xdd: num = 5;break; case 0xbd: num = 6;break; case 0x7d: num = 7;break; case 0xeb: num = 8;break; case 0xdb: num = 9;break; case 0xbb: num = 10;break; case 0x7b: num = 11;break; case 0xe7: num = 12;break; case 0xd7: num = 13;break; case 0xb7: num = 14;break; case 0x77: num = 15;break; default : break; } return num;}void main (void){ u8 cod,num; P0 = 0xff; P1 = 0xff;//端口初始化 seg_sel = 0;//LE禁止锁存 bit_sel = 0; while (1) { cod = key_scan();//判断以及编码 num = encode(cod);//解码程序。得出数字 display_led(1, num);//显示程序 }}2.电路图：
3.效果
