int main()
{
  //Row of Keypad
  //output port for 5v as input to keypad port f
  volatile char *dir_port_f , *output_f;
  dir_port_f = 0x30;
  *dir_port_f = 0x0f;
  output_f = 0x31;
  *output_f = 0x0f;


  //column of Keypad
  //input port to read keypad portk
  volatile char *dir_k , *input_k , x ;
  dir_k = 0x107;
  *dir_k =0x00;
  input_k = 0x106;
  volatile long t;

  //LED debugging column
  //to debug input to keypad porta
  volatile char *dir_port_a , *output_a;
   dir_port_a = 0x21;
   *dir_port_a = 0x0f;
   output_a = 0x22;
   //*output_a = 0x0f;
   



   //LED debugging ROW
  //to debug input to keypad porta
  volatile char *dir_port_c , *output_c;
   dir_port_c = 0x27;
   *dir_port_c = 0x0f;
   output_c = 0x28;
   //*output_a = 0x0f;


   
  while(1)
  {
  
    x = *input_k;
    //for(t = 0 ; t <=20000; t++); //Debounce
    if((x & 0x01) == 0x01)
      {
        //for(t = 0 ; t<= 200000; t++); //Debounce
        *output_a = 0x01; 
        *output_c = 0x01;
      }

    if((x & 0x02) == 0x02)
      {
        //for(t = 0 ; t<= 200000; t++); //Debounce
        *output_a = 0x02;
        *output_c = 0x01; 
      }  
    if((x & 0x04) == 0x04)
      {
        //for(t = 0 ; t<= 200000; t++); //Debounce
        *output_a = 0x04; 
        *output_c = 0x01;
      }  

    if((x & 0x08) == 0x08)
      {
        //for(t = 0 ; t<= 200000; t++); //Debounce
        *output_a = 0x08; 
        *output_c = 0x01;
      }  
    else
      *output_a = 0x00;
  }


  
  
return 0;

}