#include <reg51.h>

#define INT8U unsigned char

#define INT16U unsigned int

const INT8U SEG_CODE[]=

{0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E,0xFF};

sbit BEEP=P3^0;

INT8U pre_keyNo=0xFF,keyNo=0xFF;

void delay_ms(INT16U x)

{

INT8U t;

while (x--)

for (t=0;t<120;t++);

}

void Keys_Scan()

{

P1=0x0F;

delay_ms(1);

if(P1==0x0F)

{

keyNo=0xFF;

return;

}

switch (P1)

{

case 0x0E:keyNo=0;break;

case 0x0D:keyNo=1;break;

case 0x0B:keyNo=2;break;

case 0x07:keyNo=3;break;

  default:keyNo=0xFF;return;

}

P1=0xF0;

delay_ms(1);

switch (P1)

{

case 0xE0:keyNo+=0;break;

case 0xD0:keyNo+=4;break;

case 0xB0:keyNo+=8;break;

case 0x70:keyNo+=12;break;

  default:  keyNo=0xFF;

}

}

void Beep()

{

INT8U i;

for(i=0;i<100;i++)

{

delay_ms(1);

BEEP=~BEEP;

}

BEEP=i;

}

void main()

{

   P0=0xFF;

   while(1)

   {

Keys_Scan();

if(keyNo==0xFF)

{

delay_ms(10);

continue;

}

P0=SEG_CODE[keyNo];

Beep();

while (Keys_Scan(),keyNo!=0xFF);

}

}