简单的单片机矩阵键盘程序

#include <reg52.h>sbit ADDR0 = P1^0;sbit ADDR1 = P1^1;sbit ADDR2 = P1^2;sbit ADDR3 = P1^3;sbit ENLED = P1^4;sbit KEY1 = P2^4;sbit KEY2 = P2^5;sbit KEY3 = P2^6;sbit KEY4 = P2^7;unsigned char code LedChar[] = {  //数码管显示字符转换表    0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07,    0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71};void delay();void main(){    bit keybuf = 1;  //按键值暂存，临时保存按键的扫描值    bit backup = 1;  //按键值备份，保存前一次的扫描值    unsigned char cnt = 0;  //按键计数，记录按键按下的次数    ADDR3 = 1;    ADDR2 = 0;    ADDR1 = 0;    ADDR0 = 0;    P2 = 0xf7;   //P2.3置0，即KeyOut1输出低电平    P0 = LedChar[cnt];   //显示按键次数初值        while (1)    {        keybuf = KEY4;            //把当前扫描值暂存        if (keybuf != backup)     //当前值与前次值不相等说明此时按键有动作        {           delay();              //延时大约10ms            if (keybuf == KEY4)   //判断扫描值有没有发生改变，即按键抖动            {                if (backup == 0)  //如果前次值为0，则说明当前是弹起动作                {                    cnt++;        //按键次数+1                    if (cnt >= 10)                    {             //只用1个数码管显示，所以加到10就清零重新开始                        cnt = 0;                    }                    P0 = LedChar[cnt];  //计数值显示到数码管上                }                backup = keybuf;  //更新备份为当前值，以备进行下次比较            }        }    }}/* 软件延时函数，延时约10ms */void delay(){    unsigned int i = 1000;            while (i--);}