51单片机四路抢答器程序

#include

sbit key1=P3^0;

sbit key2=P3^1;

sbit key3=P3^2;

sbit key4=P3^3;

sbit key5=P3^7;

sbit BEEP=P2^0;

unsigned char temp;

unsigned char pulse_number1=9;

unsigned char code TAB[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,

0x7f,0x6f};

void delay_100ms(unsigned int t)

{

unsigned char i,j,k;

for(i=t;i>0;i--)

{

for(j=200;j>0;j--);

{

for(k=248;k>0;k--) ;

}

}

}

void beep()

{

BEEP=1;

delay_100ms(100);

BEEP=0;

}

void T0_int() interrupt 1

{

static unsigned char count;

unsigned char a=1;

count++;

TH0=(65536-50000)/256;

TL0=(65536-50000)%256;

if(count==20)

{

count=0;

P0=TAB[pulse_number1--];

beep();

if(pulse_number1==0)

{

P0=TAB[0];

TR0=0;

while(a)

{

beep();

if(!key5)a=0;

}

}

}

}

void main()

{

bit flag;

temp=0x00;

P2=temp;

P0=0x3f;

TMOD=0x01;

TH0=(65536-50000)/256;

TL0=(65536-50000)%256;

ET0=1;

EA=1;

TR0=1;

while(!flag)

{

if(!key1){P0=0x06;beep();flag=1;TR0=0;}

else if (!key2){P0=0x5b;beep();flag=1;TR0=0;}

else if (!key3){P0=0X4f;beep();flag=1;TR0=0;}

else if (!key4){P0=0x66;beep();flag=1;TR0=0;}

}

while(flag);

}