#include <avr/interrupt.h>

void initButton() 
{
  DDRC = 0x00; // all pins are inputs
  PORTC = 0b00110000;  // set PC4 & PC5 to INPUT_PULLUP
  
  cli();
  PCICR  |= 0b00000010; // Enables Port C Pin Change Interrupts
  PCMSK1 |= 0b00110000; // PCINT12 (pin 27) (PC4)
  sei();
}

ISR(PCINT1_vect)
{
  static unsigned long lastInterruptTime_A4 = 0;
  static unsigned long lastInterruptTime_A5 = 0;

  if(digitalRead(A4) == LOW){
    unsigned long interruptTime_A4 = millis();
    if(interruptTime_A4 - lastInterruptTime_A4 > 200) {
      currentState = nextState(currentState);
      animationTimer = 0;
    }
    lastInterruptTime_A4 = interruptTime_A4;
  }
  if(digitalRead(A5) == LOW){
    unsigned long interruptTime_A5 = millis();
    if(interruptTime_A5 - lastInterruptTime_A5 > 200) {
      currentState = nextState(currentState);
      animationTimer = 0;
    }
    lastInterruptTime_A5 = interruptTime_A5;
  }
}