PCF8574 I2C LCD Backpack Module

The PCF8574 I2C LCD Backpack Module is an I²C interface adapter designed for standard 16×2 and 20×4 HD44780-compatible character LCDs. It converts the LCD's parallel interface into a simple 4-pin connection: VCC, GND, SDA and SCL, significantly reducing the number of microcontroller GPIO pins required. ShillehTek The module includes an onboard contrast adjustment potentiometer, backlight control jumper and address-selection pads. Common PCF8574 versions use address 0x27, while PCF8574A versions commonly use 0x3F.