The I2C address of my display is 0x27 and it has 16 columns and 2 rows. It requires three variables – the I2C address of the LCD and the dimension of the LCD (columns and rows of the display).

In the second line, I create a LiquidCrystal_I2C variable. But before uploading this sketch you need to do some minor changes according to your display size and address. The below sketch will print some text on the display. To change the default address it has address selection pads – A0, A1, and A2. If you use multiple I2C devices on the same I2C bus, sometimes you need to change this default I2C address to avoid conflict with other I2C devices. Sometimes you need to change this default I2C address for a project where you use multiple I2C devices on the same I2C bus So that it does not conflict with other I2C devices. The PCF8574 chip from NXP Semiconductor uses 0x27 while the PCF8574A chip uses 0x3F. Each of these chips has its own I2C address. Some I2C LCD adapters come with PCF8574, while others use PCF8574A chips. The I2C LCD adapter also has a small trim pot to adjust the contrast of the display. You can remove the jumper to turn off the backlight LED or you can use a potentiometer in between these two pins to control the intensity of the backlight LED. These two pins are connected together by default.

One pin supplies a 5v power and another pin is for the backlight LED. There are two header pins to control the backlight of the LCD display.

Arduino wire library code