volatile int  count = 0;
void IRAM_ATTR isr()
{
  count++;
}

void setup() {
    pinMode(2, OUTPUT);
    pinMode(0, OUTPUT);
    pinMode(4, OUTPUT);
    pinMode(16, OUTPUT);
    pinMode(14, INPUT_PULLUP);

    attachInterrupt(14, isr, FALLING);
}

void loop() {
  digitalWrite(2, bitRead(count, 0));
  digitalWrite(0, bitRead(count, 1));
  digitalWrite(4, bitRead(count, 2));
  digitalWrite(16, bitRead(count, 3));
  delay(300);
}