LCD 16x2 PCF8574AT + RTC Tiny I2C

//LCD 16x2 PCF8574AT + RTC Tiny I2C V 1.3 set 2018 / Versione IDE 1.6.0
//Cerani Marco Tolentino Cotesta
#include <Wire.h>
#include <RTClib.h>
RTC_DS1307 RTC;
#include <LiquidCrystal_I2C.h>
#define DS1307_I2C_ADDRESS 0x68
LiquidCrystal_I2C lcd(0x3F,16,2);
char daysOfTheWeek[7][10] = {"Do", "Lu", "Ma", "Me", "Gio", "Ve", "Sa"};
char bufferRX[50];
void setup()
{
  Serial.begin(9600);
  Serial.println("Per aggiornare data e ora inviare il seguente comando: ");
  Serial.println("\"setDateTime anno, mese, giorno, ora, minuti, secondi\"");
  Serial.println("17:30 del 8 sett 2018");
  Serial.println("Esempio: setDateTime, 2018, 9, 8, 17, 30, 00");
  lcd.init();
  lcd.backlight();
}
void loop()
{
  static unsigned long updateTime;
  if(millis() - updateTime > 1000){
    updateTime = millis();
    DateTime now = RTC.now();
    lcd.clear();
    lcd.setCursor(0, 0);
    LCDPrintNum(now.hour());
    lcd.print(":");
    LCDPrintNum(now.minute());
    lcd.print(":");
    LCDPrintNum(now.second());
    lcd.print(" ");
    lcd.print(daysOfTheWeek[now.dayOfTheWeek()]);
    lcd.setCursor(0, 1);
    LCDPrintNum(now.day());
    lcd.print("/");
    LCDPrintNum(now.month());
    lcd.print("/");
    lcd.print(now.year(), DEC);
  }
  readSerial();
}
void LCDPrintNum(int num){
  if(num <10)
    lcd.print("0");
  lcd.print(num);
}
void readSerial(){
  while (Serial.available() > 0) {
    Serial.readBytesUntil('\n', bufferRX, sizeof(bufferRX) - 1);
    if(strstr(bufferRX, "setDateTime,")){
      int tdArray[6];
      char * pch = strtok (bufferRX, " ,");
      unsigned int i = 0;
      while (pch != NULL){
        if(i > 0)
          tdArray[i-1] = atoi(pch);
        pch = strtok (NULL, " ,");
        i++;
      }
      DateTime newTime = DateTime(tdArray[0], tdArray[1], tdArray[2], tdArray[3], tdArray[4], tdArray[5]);
      RTC.adjust(newTime);
      Serial.println("Impostato nuovo orario.");
    }
  }
}