Arduino 4x4 Keypad Password

/*
  Aluno: Wesley Alves Santana
  Turma: 3IELN2017
  Simulação: https://circuits.io/circuits/4014551-sistemas-programaveis-keypad-diplsay-de-7-segmentos/
*/

// Keypad:
const byte ROW[] = {A0, A1, A2, A3};
// Display 7 segmentos:
const byte COL[] = {2, 3, 4, 5};
// Segmentos:        a,  b,  c,  d,  e,  f,  g,  p
const byte SEG[] = {12, 13,  7,  8,  9, 11, 10,  6};
// Teclado:
const char KEYS[4][4] = {{'A', 'B', 'C', 'D'}, {'3', '6', '9', '#'}, {'2', '5', '8', '0'}, {'1', '4', '7', '*'}};
//Senha Padrão:
const char PASSWORD[] = {'B', 'C', 'D', '8', '4', '2'};

void setup() {
  for (byte i = 2; i <= 13; i++) {
    pinMode (i, OUTPUT);
    digitalWrite (i, LOW);
  }
  Serial.begin(9600);
  Serial.println("=========================");
}

void loop() {
  delay(10);
  char pressedKey = getKey();
  if (pressedKey != 'w') {
    senha(pressedKey);
  }
}

char scanKey() {
  char r = 'w';
  for (byte i = 0; i < 4; i++) {
    digitalWrite(COL[i], HIGH);
    for (byte j = 0; j < 4; j++) {
      if (digitalRead(ROW[j])) {
        r = KEYS[i][j];
      }
    }
    digitalWrite(COL[i], LOW);
  }
  return r;
}

char getKey() {
  static byte estado = 0;
  char key = 'w';
  char scan = scanKey();
  switch (estado) {
    case 0:
      if (scan != 'w') {
        estado = 1;
        key = scan;
      }
      break;
    case 1:
      if (scan == 'w') {
        key = 'w';
        estado = 0;
      }
      break;
  }
  return key;
}

void senha(char pressedKey) {
  static bool keepTesting = true, checkPass = false;
  static byte counter = 0;
  if (pressedKey != '#') {
    Serial.print(pressedKey);
    if (keepTesting) {
      if (counter <= 5 && pressedKey == PASSWORD[counter]) {
        checkPass = true;
        counter++;
      } else {
        checkPass = false;
        keepTesting = false;
      }
    }
  }  else if (checkPass) {
    counter = 0;
    keepTesting = true;
    Serial.println("\nSenha correta.");
  } else {
    counter = 0;
    keepTesting = true;
    Serial.println("\nSenha errada.");
  }
}