IIC/I2C Serial Interface Adapter Module

Product Description

The I2C/IIC Serial Interface Adapter Module is a compact PCF8574-based interface board designed to easily connect standard 16×2 and 20×4 character LCD displays to Arduino, ESP32, ESP8266, and other compatible microcontrollers. It converts the LCD’s parallel interface into a simple I2C serial connection, reducing the number of microcontroller pins required for communication.

With this adapter, the LCD can be controlled using just two communication lines, SDA and SCL, along with power and ground. This makes wiring simpler and leaves additional GPIO pins available for sensors, motors, buttons, and other peripherals.

The module supports standard HD44780-compatible LCDs in 4-bit mode and works with commonly used LCD libraries, making it suitable for both beginners and experienced developers. An onboard potentiometer allows easy contrast adjustment, while the jumper provides convenient backlight control.

Features

• Supports 16×2 and 20×4 character LCD displays
• Based on PCF8574 I2C controller
• Converts parallel LCD interface to I2C
• Requires only SDA and SCL communication lines
• Compatible with HD44780-compatible LCDs
• Compatible with Arduino, ESP32, ESP8266, and other microcontrollers
• 5V power supply
• Adjustable LCD contrast
• Onboard backlight control jumper
• Configurable I2C address
• Default I2C address: 0x3F
• Address can be adjusted using onboard solder jumpers
• Compact design
• RoHS compliant

Specifications

Parameter	Specification
Controller IC	PCF8574
Interface	I2C / IIC
Supported LCD	16×2 / 20×4
LCD Compatibility	HD44780-compatible
Operating Voltage	5V
Default I2C Address	0x3F
Address Configuration	Solder Jumpers
Contrast Adjustment	Onboard Potentiometer
Backlight Control	Jumper
Module Dimensions	Approx. 41.6 × 19.2mm
Communication Lines	SDA, SCL

Working Principle

The PCF8574 IC acts as an I2C-to-parallel converter. The microcontroller sends commands and display data through the SDA and SCL lines. The PCF8574 then converts these serial signals into the parallel signals required by the LCD.

This allows a standard LCD to be controlled while using significantly fewer GPIO pins than a conventional parallel connection.

I2C Address

The module comes with a default I2C address of 0x3F. The address can be configured using the onboard solder jumpers, allowing multiple LCD modules to be used on the same I2C bus when unique addresses are assigned.

Contrast and Backlight Control

An onboard potentiometer is provided to adjust the LCD contrast for clear character visibility. The backlight can be controlled using the onboard jumper, allowing the user to enable or disable the LCD backlight as required.

Applications

• Arduino LCD projects
• ESP32 projects
• ESP8266 projects
• Robotics
• IoT devices
• Sensor dashboards
• Control panels
• Embedded systems
• DIY electronics
• Data monitoring systems
• Automation projects
• Educational projects
• Character display applications

Advantages

• Saves valuable GPIO pins
• Simple I2C wiring
• Easy LCD integration
• Supports both 16×2 and 20×4 LCDs
• Adjustable contrast
• Convenient backlight control
• Configurable I2C address
• Compact and lightweight
• Works with popular microcontroller platforms
• Compatible with commonly used LCD libraries

Package Includes

• 1 × I2C/IIC Serial Interface Adapter Module – PCF8574 Based

Note: The LCD display is not included unless specifically mentioned in the product package.

Product Disclaimer

Product images are for representation purposes only. The actual product may vary slightly in PCB layout, component placement, colour, or appearance depending on stock availability and manufacturing batch. Please verify the I2C address and pin configuration before connecting the module to your project.