1.21

 #include<reg52.h>


//sbit Led1 = P0^0;
sbit Latch_seg = P2^0;
sbit Latch_bit = P2^1;
sbit BUZZ = P2^2;
 
void delay(unsigned char cnt);


/*unsigned char code LedChar[16]={
   0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E
};*/
unsigned char code LedChar[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
unsigned char code LedBuff[] = {0xFE,0xFD,0xFB,0xF7,0xEF,0xDF,0xBF,0x7F};
unsigned char Led[8] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
unsigned int sec = 9;
unsigned int ms = 99;
bit flag = 0;
bit openbuzz = 0;
bit run = 1;
unsigned char k = 0;


void main()
{
EA = 1;
     TMOD = 0x01;
TH0 = 0xFC;
TL0 = 0x67;
ET0 = 1;
     TR0 = 1; 


while(1)
{
/////////////////////////////////////1秒计时数码管
   if((flag == 1)&&(run == 1))
{
flag = 0;
   ms--;
if(ms <= 0)
{
   ms = 99;
sec--;
if(sec <= 0)
{
   ms = 0;
                    sec = 0;
openbuzz = 1;
run = 0;
}
}
   Led[7] = LedChar[ms%10];
       Led[6] = LedChar[ms/10];
       Led[5] = 0x40;
       Led[4] = LedChar[sec%10];
       Led[3] = LedChar[sec/10];
       Led[2] = 0x00;
Led[1] = 0x00;
Led[0] = 0x00;
   }
 }
}


void InterruptTimer0() interrupt 1
{
static unsigned int cnt = 0;


     TH0 = 0xFC;
TL0 = 0x67;
cnt++;
if(cnt >= 10)
{
    cnt = 0;
flag = 1;
}
if(openbuzz == 1)
{
    BUZZ = ~BUZZ;
}
P0 = 0xFF;
switch(k)
{
    case 0:  P0 = Led[0];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[0];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
case 1:  P0 = Led[1];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[1];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
    case 2:  P0 = Led[2];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[2];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
case 3:  P0 = Led[3];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[3];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
case 4:  P0 = Led[4];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[4];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
case 5:  P0 = Led[5];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[5];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
case 6:  P0 = Led[6];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[6];
             Latch_bit = 1;
             Latch_bit = 0;
 k++;
 break;
    case 7:  P0 = Led[7];
             Latch_seg = 1;
             Latch_seg = 0;
             P0 = LedBuff[7];
             Latch_bit = 1;
             Latch_bit = 0;
 k=0;
 break;
default:break;
}
}