#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int 

sbit LED=P1^0;
sbit DOUT=P2^0;

void delay()
{
uchar m,n,s;
for(m=20;m>0;m--)
for(n=20;n>0;n--)
for(s=248;s>0;s--);
}

void main()
{
while(1) 
{
LED=0;
if(DOUT==0)
{
delay();
if(DOUT==0)
{
LED=1;
delay();
}
}
}
}