void setup() {
  Serial.begin(9600);
  DDRA |= 0xFF;
  DDRK |= 0x00; 
  DDRF |= 0xFF;
}
void loop() {
  unsigned char digits[] = {
    0x3F, // 0
    0x06, // 1
    0x5B, // 2
    0x4F, // 3
    0x66, // 4
    0x6D, // 5
    0x7D, // 6
    0x07, // 7
    0x7F, // 8
    0x6F  // 9
  };
  int keymap[4][3]={
    {1, 2, 3},
    {4, 5, 6},
    {7, 8, 9},
    {-1, 0, -1}
  };
  unsigned int row,col;
  for(row = 0; row < 4; row++) {
    PORTF =(1<<row);
    for(col = 0; col < 3; col++) {
      if (PINK & (1 << col)) {
        int numPressed = keymap[row][col];
        if (numPressed>=0) {
          PORTA = digits[numPressed];
          Serial.println(numPressed);
          delay(500);
        }
      }
    }
  }
}