// Configuation
// Port B 0 - 3 - LED Port 4 - 7
// Port D 4 - 7 - LED Port 0 - 3
// PORT C 0 - 3 - Keypad Row 1 - 4
// Port C 4 - 5 - Keypad Col 2 - 3
// Port C 2 -3  - Keypad Col 0 - 1
// Keypad configuation
// 1 - 1; 2 - 2; 3 - 3 

void init_port(void);
void outport(char);
void delay1(int);
char inport(void);
char scan_keypad(void);
void outportc(char);

void setup() {
  char x;
  outport(0);
  init_port();
  x = scan_keypad();
  while(1)
  {
    while(x == 0)
    {
      x = scan_keypad();
      delay1(1);
    }
    outport(x);
    x = 0;
  }
}
;
char scan_keypad()
{
  int i,row,col,column;
  char j,k,rdata;
  for(row =0; row<4; row++)
  {
    outportc(~(1<<row));
    for(col=0; col<4; col++)
    {
      column = inport();
      if(column != 0x0)
      {
        delay1(1);
        for(col=0; col<4; col++)
        {
          if(column == (1 << col))
          {
            rdata = row * 4 + col + 1;
            delay1(1);
            return(rdata);
          }
        }

      }
    }
  }
  return(0);
}
void init_port()
{
  char *portb_dir  = (char *)0x24;
  char *portc_dir  = (char *)0x27;
  char *portd_dir  = (char *)0x2A;

  *portb_dir = 0x0F;
  *portd_dir = 0xF0;
  *portc_dir = 0x0F;
}

void outport( char out_data)
{
  char *portb_data = (char *)0x25; 
  char *portd_data = (char *)0x2B; 
  *portb_data = out_data >> 4;
  *portd_data = out_data << 4;
}

void outportc( char out_data)
{
  char *portc_data = (char *)0x28; 
  *portc_data = out_data;
}

void delay1(int count)
{
  volatile long i;
  while(count)
  {
    for(i=0; i<1000; i++);
    count--;
  }
}

char inport(void)
{
  char indata,datad,datac;
  char *portc_data = (char *)0x26; 
  char *portd_data = (char *)0x29; 
  datad = *portd_data;
  datac = *portc_data;
  indata = (((datac & 0x30)>>2) & 0x0F) | ((datad & 0x0C) >> 2);
  indata = ~indata & 0x0F;
  return(indata);
}


void loop() {

}