#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

#define ENCODER_CLK 2
#define ENCODER_DF 3
#define ENCODER_SW 4

int counter = 0;

void setup() {
  // put your setup code here, to run once:
  lcd.init();
  lcd.backlight();

  pinMode(ENCODER_CLK, INPUT);
  pinMode(ENCODER_DF, INPUT);
  pinMode(ENCODER_SW, INPUT_PULLUP);

  attachInterrupt(digitalPinToInterrupt(ENCODER_CLK), readEncoder, FALLING);
}

void readEncoder() {
  int dtValue = digitalRead(ENCODER_DF);
  if (dtValue == HIGH) {
    counter++;
  }
  if (dtValue == LOW ) {
    counter--;
  }
  
}

int getCounter(){
  int result;
  noInterrupts();
  result=counter;
  interrupts();
  return result;
}

void resetCounter(){
  noInterrupts();
  counter=0;
  interrupts();
}

void loop() {
  // put your main code here, to run repeatedly:
  lcd.setCursor(3,0);
  lcd.print("Counter ");
  lcd.setCursor(7,1);
  lcd.print(getCounter());
}