#define SET0(REG,BIT) REG &= ~(1<<BIT)
#define SET1(REG,BIT) REG |= (1<<BIT)

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27 ,16, 2);


void setup() {

  SET0 (DDRD,2);
  lcd.init();
  lcd.backlight();




   SET0(ADMUX,REFS1); // voľba Aref
   SET0(ADMUX,REFS0);
   SET1(ADMUX,ADLAR); // zarovnanie nahor
   SET1(ADMUX,MUX0); // voľba kanála ADC1
   SET0(ADMUX,MUX1);
   SET0(ADMUX,MUX2);
   SET0(ADMUX,MUX3);
   SET1(ADIE,SREG);
   SET1(ADCSRA,ADATE); // spúšťanie príkazom
   SET0(ADCSRA,ADIE); // negenerovanie prerušenia
   SET1(ADCSRA,ADPS2); // voľba preddeličky 128 
   SET1(ADCSRA,ADPS1);
   SET1(ADCSRA,ADPS0);
   SET1(ADCSRA,ADEN); // zapnutie ADC


}

void loop() {
lcd.println(ADCH);

}