#include <REG2051.H>		
#define uint unsigned int	
#define uchar unsigned char	
uchar flag;
/****************************/
void delay(uint k)				
{							
uint data i,j;						
for(i=0;i<k;i++)					
{for(j=0;j<10000;j++)					
{;}}							
}							
/**********************************/
uchar scan_key(void)
{
uchar temp;
temp=P3;
return temp;
}
/***********************************/
void main(void)		
{							
	   while(1)						
	  {
	   P3=0xfe;
	   if(P3!=0xfe)
	   {
 	   delay(5);		
	   P3=0xfe;
		if(P3!=0xfe)flag=scan_key();
	   }
	   else flag=0;
	   switch(flag)
	   {
	   case 0xfd:P1=0xfe;
	   delay(1000);
	   default:P1=0xff;break;
      }
	 }			
}