int input_pin = 2;
volatile int value;

void setup() {
    pinMode(input_pin, INPUT);
    attachInterrupt(digitalPinToInterrupt(input_pin), state, RISING);
    DDRC = 0xFF;
    Serial.begin(9600);
}

void loop() {
    PORTC = (1 << PC4) | (1 << PC5) | (1 << PC6) | (1 << PC7);
    delay(1000);
    PORTC = (0 << PC4) | (0 << PC5) | (0 << PC6) | (0 << PC7);
    delay(1000);
}

void state() {
    value = digitalRead(input_pin);
    Serial.print("Input reading: ");
    Serial.println(value);
}