C51单片机项目：时钟

#include<reg52.h>

sbit ADDR0 = P1^0;
sbit ADDR1 = P1^1;
sbit ADDR2 = P1^2;
sbit ADDR3 = P1^3;
sbit ENLED = P1^4;
sbit ENLCD = P1^5;
sbit KeyIn2 = P2^5;
sbit KeyIn3 = P2^6;
sbit BUZZ = P1^6;
unsigned char LED[]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};

void main()
{
    bit buff=1;//buf为KeyIn2上一次状态
    bit bufff=1;//buf为KeyIn3上一次状态
    unsigned int i,tt;
    static char bit_p[6]={0,0,0,0,0,0};
    static int cnt,sec,min,hour;
    i = 0;
    sec=0;
    min=0;
    hour=0;
    ENLED = 0;
    ENLCD = 0;
    ADDR3 = 1;
    TMOD = 0x10;
    TH1 = 0xFC;
    TL1 = 0x66;
    TR1 = 1;
    P2 = 0xFE;

    while(1)
    {
        if(TF1==1)
        {
            TF1 = 0;
            TH1 = 0xFC;
            TL1 = 0x66;
            cnt++;
            if(cnt ==1000)
            {
                cnt = 0;
                //秒
                sec++;
                bit_p[0]=sec%10;
                bit_p[1]=sec/10%10;
                if(sec==60)
                {
                    sec=0;
                    //分钟
                    min++;
                    bit_p[2]=min%10;
                    bit_p[3]=min/10%10;
                }
                if(min==60)
                {
                    min=0;
                    //小时
                    hour++;
                    bit_p[4]=hour%10;
                    bit_p[5]=hour/10%10;
                }
            }
            switch (i)
            {
                case 0:ADDR2 = 0;ADDR1 = 0;ADDR0 = 0;P0 = LED[bit_p[0]];i++;break;
                case 1:ADDR2 = 0;ADDR1 = 0;ADDR0 = 1;P0 = LED[bit_p[1]];i++;break;
                case 2:ADDR2 = 0;ADDR1 = 1;ADDR0 = 0;P0 = LED[bit_p[2]];i++;break;
                case 3:ADDR2 = 0;ADDR1 = 1;ADDR0 = 1;P0 = LED[bit_p[3]];i++;break;
                case 4:ADDR2 = 1;ADDR1 = 0;ADDR0 = 0;P0 = LED[bit_p[4]];i++;break;
                case 5:ADDR2 = 1;ADDR1 = 0;ADDR0 = 1;P0 = LED[bit_p[5]];i=0;break;
            }
        }
            //设置时钟的分钟
            if(KeyIn2!=buff)
            {
                if(buff==0)
                 {
                    TR1=0;
                    min--;
                    if(min==-1)
                    {
                        min=60;
                    }
                    bit_p[2]=min%10;
                    bit_p[3]=min/10%10;
                }
                buff=KeyIn2;
                TR1=1;
            }

            //设置时钟的小时
            if(KeyIn3!=bufff)
            {
                if(bufff==0)
                 {
                    TR1=0;
                    hour--;
                    if(hour==-1)
                    {
                        hour=24;
                    }
                    bit_p[4]=hour%10;
                    bit_p[5]=hour/10%10;
                }
                bufff=KeyIn3;    //buf = 0，keyIn2=0
                TR1=1;
            }

            //自己设置闹钟 00:00:10
            if(sec==10)
            {
                BUZZ=~BUZZ;
                for(tt=0;tt<2000;tt++);
            } 

}    }

C51单片机，时钟时间显示，蜂鸣器一到指定时间可以响。