bool Cstate[4]={1,1,1,1};
bool btnPressed = 0;
bool bPressed = 0;
byte Col,Row;
byte button;

byte hexaKeys[4][4] = {
  {1, 2, 3, 4},
  {5, 6, 7, 8},
  {9, 10, 11, 12},
  {13, 14, 15, 16}
};

bool checkBtn(){
 for(int i=0;i<4;i++){
    //Cstate[i] = digitalRead(i+8);  //Check if a collumn is pressed
    //if (Cstate[i] == 0){           //If yes
    if (!(PINB & (1<<i))){ 
      //Cstate[i] = 1;
      Col = i+1;                   //save col number
      bPressed = 1;
      for(int i=0;i<4;i++){
        PORTD |= (1<<i+4);
          //if (digitalRead(Col+7) == 1){  //when the col turns high
          if (PINB & (1<<Col-1)){
            Row = i+1;                  //we know the row now, save it
            PORTD &= ~(0b11110000);
            delay(250);
            //break;
            goto get_out;
          }
        }  
    }
  }
get_out:;
}


void setup() {
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, INPUT_PULLUP);
  pinMode(9, INPUT_PULLUP);
  pinMode(10, INPUT_PULLUP);
  pinMode(11, INPUT_PULLUP);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
Serial.begin(115200);
}

void loop() {
unsigned long start = micros();
 checkBtn();
unsigned long finish = micros();
if(bPressed == 1){
  bPressed = 0;
  button = hexaKeys[Row-1][Col-1];
  Serial.print(button);
  Serial.print(" took ");
  Serial.println(finish - start - 250000);
}
switch (button){
  case 1:

  break;

  case 2:

  break;

  case 3:

  break;

  case 4:

  break;

  case 5:

  break;

  case 6:

  break;

  case 7:

  break;

  case 8:

  break;

  case 9:

  break;

  case 10:

  break;

  case 11:

  break;

  case 12:

  break;

  case 13:

  break;

  case 14:

  break;

  case 15:

  break;

  case 16:

  break;
}
}