#include <avr/io.h>
#include <LiquidCrystal_I2C.h>
#define NUMC 3
LiquidCrystal_I2C lcd(0x27, 16, 2);

volatile uint8_t n;
ISR(INT0_vect){
  n++;
  n %= NUMC;
}
enum MSGS{
  MSG0,
  MSG1,
  MSG2
};

void setup() {
 DDRD = 0;//input
 PORTD = 1 << PD2;//interal pull up
 lcd.init();
 lcd.backlight();
 EIMSK |= 1 << INT0;//Enable ext interrupt INT0
 EICRA |= 0b00000010;//Trig. INT0 on falling edge
 sei();
}

void print_msg(int n)
{
  switch(n){
    case MSGS::MSG0:
      lcd.print("Hello !");
      break;
    case MSGS::MSG1:
      lcd.print("Welcome to AAU");
      break;
    case MSGS::MSG2:
      lcd.print("RTGP Spring 2024");
      break; 
    default:
      break;
  }

}

int main() {
 init();
 setup();
 n=0;
 for(;;)
 {
  print_msg(n);
  _delay_ms(1000);
  lcd.clear();
  }
}