#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit beep=P0^0;
void delay(uint z)
{
uint x,y;
for(x=z;x>0;x--)
for(y=111;y>0;y--);
}
void main()
{
while(1)
{
beep=0;
delay(500);
beep=1;
delay(500);
}
}