基于stc89c52RC单片机的倒计时的代码

以下是基于STC89C52RC单片机的倒计时代码：

#include <reg52.h>
#include <intrins.h>

typedef unsigned char uchar;
typedef unsigned int uint;

#define LED P0

sbit KEY1 = P3^2;
sbit KEY2 = P3^3;
sbit KEY3 = P3^4;

uchar code table[]={
    0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90
};

uint count = 0;

void delayms(uint xms) {
    uint i,j;
    for(i=xms;i>0;i--)
        for(j=110;j>0;j--);
}

void display() {
    uchar i,j;
    for(i=0;i<6;i++) {
        switch(i) {
            case 0:
                j = count / 60000;
                break;
            case 1:
                j = count % 60000 / 10000;
                break;
            case 2:
                j = count % 10000 / 1000;
                break;
            case 3:
                j = count % 1000 / 100;
                break;
            case 4:
                j = count % 100 / 10;
                break;
            case 5:
                j = count % 10;
                break;
        }
        LED = table[j];
        _nop_();
        _nop_();
        _nop_();
        LED = 0x00;
        delayms(1);
    }
}

void main() {
    KEY1 = 1;
    KEY2 = 1;
    KEY3 = 1;
    while(1) {
        if(KEY1 == 0) {
            delayms(5);
            if(KEY1 == 0) {
                while(!KEY1);
                count += 60000;
            }
        }
        if(KEY2 == 0) {
            delayms(5);
            if(KEY2 == 0) {
                while(!KEY2);
                count += 1000;
            }
        }
        if(KEY3 == 0) {
            delayms(5);
            if(KEY3 == 0) {
                while(!KEY3);
                count = 0;
            }
        }
        display();
    }
}

该代码使用了STC89C52RC单片机，通过按键控制倒计时时间，并在LED数码管上显示倒计时的时间。按一次KEY1加1分钟，按一次KEY2加1秒钟，按一次KEY3清零倒计时时间。