void setup() 
{ 
  volatile char *dirf,*dira,*outf,*ina;
  volatile long i,x,j;
   dirf=0x30; dira=0x21; outf=0x31; ina=0x20;
  *dirf=0xFF; *dira=0x00; 
  
  while(1)  
  {
    i=0;
    x=*ina;
    
    if(((x & 0x01) == 0x01) && ((x & 0x40) == 0x40))
    
    {       
      *outf = 0x10;
      //for (i=0; i<2000000; i++);      
      } 
      *outf = 0x00;
  }     
    
  }