采用P0口设计一个4*4行列式按键，采用P1 P2口设计8个8段数码管，P1作公共的段选线，送出显示数字的编码;P2口作为数码管的位选线，负责数码管的分时显示，每位数码管显示2ms。通过按键，可以输入0-9 A-F 不同的值，在数码管上显示最高8位的值。给我写代码

下面是一个简单的基于51单片机的程序，实现了上述功能。本程序使用定时器中断实现了分时显示，使用了一个16*8的编码表将要显示的数字转换为了段选编码值。

#include <reg51.h>

// 定义IO口
sbit P0_0 = P0^0;
sbit P0_1 = P0^1;
sbit P0_2 = P0^2;
sbit P0_3 = P0^3;

sbit P1_0 = P1^0;
sbit P1_1 = P1^1;
sbit P1_2 = P1^2;
sbit P1_3 = P1^3;
sbit P1_4 = P1^4;
sbit P1_5 = P1^5;
sbit P1_6 = P1^6;
sbit P1_7 = P1^7;

sbit P2_0 = P2^0;
sbit P2_1 = P2^1;
sbit P2_2 = P2^2;
sbit P2_3 = P2^3;
sbit P2_4 = P2^4;
sbit P2_5 = P2^5;
sbit P2_6 = P2^6;
sbit P2_7 = P2^7;

// 定义变量
unsigned char key = 0;  // 按键值
unsigned char disp[8] = {0};  // 要显示的数字（BCD码）
unsigned char code seg_table[16][8] = {  // 编码表
    {1,1,1,1,1,1,0,0},  // 0
    {0,1,1,0,0,0,0,0},  // 1
    {1,1,0,1,1,0,1,0},  // 2
    {1,1,1,1,0,0,1,0},  // 3
    {0,1,1,0,0,1,1,0},  // 4
    {1,0,1,1,0,1,1,0},  // 5
    {1,0,1,1,1,1,1,0},  // 6
    {1,1,1,0,0,0,0,0},  // 7
    {1,1,1,1,1,1,1,0},  // 8
    {1,1,1,1,0,1,1,0},  // 9
    {1,1,1,0,1,1,1,0},  // A
    {0,0,1,1,1,1,1,0},  // B
    {1,0,0,1,1,1,0,0},  // C
    {0,1,1,1,1,0,1,0},  // D
    {1,0,0,1,1,1,1,0},  // E
    {1,0,0,0,1,1,1,0},  // F
};

// 定时器中断
void timer0_isr(void) interrupt 1 {
    static unsigned char cnt = 0;  // 计数器
    static unsigned char pos = 0;  // 当前显示的数码管位置

    // 分时显示
    P2_0 = (pos == 0);
    P2_1 = (pos == 1);
    P2_2 = (pos == 2);
    P2_3 = (pos == 3);
    P2_4 = (pos == 4);
    P2_5 = (pos == 5);
    P2_6 = (pos == 6);
    P2_7 = (pos == 7);

    // 显示数字
    P1 = seg_table[disp[pos]][cnt];

    // 更新计数器和位置
    cnt++;
    if (cnt == 8) {
        cnt = 0;
        pos++;
        if (pos == 8) {
            pos = 0;
        }
    }
}

// 读取按键
unsigned char read_key(void) {
    unsigned char key_value = 0;
    P0_0 = 0;
    if (P0_4 == 0) key_value = 1;
    if (P0_5 == 0) key_value = 2;
    if (P0_6 == 0) key_value = 3;
    if (P0_7 == 0) key_value = 0;
    P0_0 = 1;

    P0_1 = 0;
    if (P0_4 == 0) key_value = 4;
    if (P0_5 == 0) key_value = 5;
    if (P0_6 == 0) key_value = 6;
    if (P0_7 == 0) key_value = 0;
    P0_1 = 1;

    P0_2 = 0;
    if (P0_4 == 0) key_value = 7;
    if (P0_5 == 0) key_value = 8;
    if (P0_6 == 0) key_value = 9;
    if (P0_7 == 0) key_value = 0;
    P0_2 = 1;

    P0_3 = 0;
    if (P0_4 == 0) key_value = 0;
    if (P0_5 == 0) key_value = 0;
    if (P0_6 == 0) key_value = 0;
    if (P0_7 == 0) key_value = 0;
    P0_3 = 1;

    return key_value;
}

// 延时函数
void delay(unsigned int t) {
    while (t--);
}

// 主函数
void main() {
    // 初始化端口
    P0 = 0xff;
    P1 = 0xff;
    P2 = 0xff;
    TMOD = 0x01;
    TH0 = 0xfc;
    TL0 = 0x66;
    TR0 = 1;
    ET0 = 1;
    EA = 1;

    while (1) {
        // 读取按键
        key = read_key();

        // 处理按键
        if (key != 0) {
            delay(1000);  // 消抖
            if (key != 0) {
                // 显示按键值
                if (key <= 9) {
                    disp[7] = key;
                } else {
                    disp[7] = key - 7;
                }
            }
        }

        // 更新显示
        delay(1000);  // 延时
    }
}