Description
The PCF8574 IIC/I2C 16 Pin Serial Interface LCD Display Adapter Module is a compact daughterboard designed to add I2C communication to standard 16-pin character LCD displays. It uses the PCF8574 I2C I/O expander to convert serial I2C data into the parallel signals required by the LCD.
Instead of connecting multiple LCD data and control wires directly to your Arduino or other microcontroller, this module allows the display to be controlled through the I2C interface using only SDA and SCL, along with power and ground. This helps reduce wiring and frees up GPIO pins for other components.
The module is compatible with common 16×2 and 20×4 character LCD displays and includes a built-in potentiometer for contrast adjustment and a jumper for controlling the LCD backlight.
Key Features
- Built-in PCF8574 I2C I/O expander
- Converts I2C serial data to LCD parallel signals
- Compatible with standard 16×2 and 20×4 LCD displays
- Uses only two communication lines: SDA and SCL
- Operating voltage: 5V
- Adjustable LCD contrast using onboard potentiometer
- Backlight ON/OFF control through jumper
- Two I2C interface connectors
- Selectable I2C address using solder jumpers
- Supports multiple modules on the same I2C bus
- Compact and easy-to-install design
- RoHS compliant
Specifications
| Specification | Details |
|---|---|
| IC / Controller | PCF8574 |
| Interface | IIC / I2C |
| Operating Voltage | 5V |
| Compatible LCD | 16×2 / 20×4 Character LCD |
| Communication Lines | SDA, SCL |
| Contrast Adjustment | Onboard Potentiometer |
| Backlight Control | Jumper |
| I2C Address | Commonly 0x27 or 0x3F |
| Address Selection | Solder Jumpers |
| I2C Modules per Bus | Up to 8, depending on address configuration |
| Interface Connector | 2 × I2C Interface |
| Dimensions | 41.6 × 19.2 mm |
I2C Address
Depending on the version of the adapter, the default I2C address may be 0x27 or 0x3F. Address selection can be configured using the solder pads on the module.
For versions with A0, A1 and A2 solder pads, the address can be adjusted according to the jumper configuration. This makes it possible to use multiple compatible modules on the same I2C bus when different addresses are available.
Easy LCD Connection
The PCF8574 adapter significantly reduces the number of connections required between an LCD and a microcontroller. Instead of using several GPIO pins for the LCD’s parallel interface, your controller communicates through the I2C SDA and SCL lines.
This makes the module especially useful when your project has limited GPIO pins or when you want to keep wiring clean and simple.
Backlight and Contrast Control
An onboard potentiometer allows you to adjust the LCD contrast for clear and readable characters. The backlight can be enabled or disabled using the jumper provided on the adapter board.
Compatible Projects
- Arduino Uno and other Arduino boards
- 16×2 LCD displays
- 20×4 LCD displays
- Raspberry Pi projects
- Microcontroller-based systems
- Sensor monitoring systems
- Digital clocks and timers
- DIY control panels
- Home automation projects
- Embedded electronics projects
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