Scan LCD IIC address and init LCD module automatically.

LiquidCrystal_I2C_Scan_Gist.ino

//
// Copyright (c) 2019 Conplug (https://conplug.com.tw)
// Author: Hartman Hsieh
//
// Description :
//   Scan LCD IIC address and init LCD module automatically.
//
// Connections :
//   Connect LCD module to IIC bus.
//
// Required Library :
//   https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library
//

#include  <Wire.h> // IIC bus

const int TryLcdAddress[] = {0x27, 0x3f}; // Add other addresses
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C* Lcd = 0;

void setup() {

  Wire.begin(); // Join IIC bus

  Serial.begin(9600);
  
  //
  // Scan Lcd IIC address in table - TryLcdAddress.
  //
  Serial.println("Try IIC address for LCD module.");
  for(int i = 0; i < sizeof(TryLcdAddress); i++) {
    Wire.beginTransmission(TryLcdAddress[i]);
    uint8_t data8 = Wire.endTransmission();
    if (data8 == 0) {
      Serial.print("IIC address of LCD module is 0x");
      Serial.println(TryLcdAddress[i], HEX);
      Lcd = new LiquidCrystal_I2C(TryLcdAddress[i], 16, 2);
      break;
    }
  }

  //
  // Check the scanning result.
  //
  if(Lcd == 0) {
    Serial.println("ERROR : Address not found");
  }

  Lcd->begin();
  Lcd->backlight();

  Lcd->setCursor(0, 0);
  Lcd->print(" conplug.com.tw ");
  Lcd->setCursor(0, 1);
  Lcd->print("  Hello World!  ");
  delay(5000);
}

void loop() {
  Lcd->setCursor(0, 1);
  Lcd->print("                ");
  Lcd->setCursor(0, 1);
  Lcd->print(millis());
  delay(1000);
}