PCF8574T I2C I/O Expansion Board – 8-Bit GPIO Expander

Product Description

The PCF8574T I2C I/O Expansion Board is an 8-bit I/O expander module designed to add additional digital input/output ports to microcontroller and development-board projects using the I2C communication interface. It is useful when the available GPIO pins on a controller are insufficient for connecting multiple switches, LEDs, sensors, displays, and other peripherals.

Based on the PCF8574T chip, the module provides 8-bit parallel I/O expansion while requiring only the I2C communication lines from the host controller. Up to 8 PCF8574-based modules can be connected on the same I2C bus when different I2C addresses are configured, providing up to 64 additional I/O ports.

The board features an I2C pin header on one side and an I2C connector on the opposite side, making wiring convenient and supporting I2C cascading between multiple modules. It is suitable for use with platforms such as Arduino and Raspberry Pi.

Features

• Based on PCF8574T I/O expander IC
• Provides 8-bit parallel I/O expansion
• Uses the I2C interface
• Up to 8 modules can be connected to the same I2C bus
• Supports up to 64 I/O ports using multiple modules
• I2C pin header and connector provided on opposite sides
• Supports convenient I2C cascading
• Reduces the number of GPIO pins required from the host controller
• Compatible with Arduino and Raspberry Pi
• Suitable for compact embedded and DIY projects

Specifications

Working Principle

The PCF8574T communicates with a microcontroller through the I2C bus, typically requiring only the I2C communication lines. The host controller sends commands through the I2C interface, and the PCF8574T provides access to its 8 digital I/O pins.

This allows a controller with limited GPIO availability to control or read additional digital devices. Multiple compatible boards can be connected to the same I2C bus using different addresses, expanding the available I/O capacity.

I2C Cascading

The board is designed with an I2C pin header and I2C connector on opposite sides. This arrangement makes it convenient to connect multiple boards together.

When multiple PCF8574 modules are used with different valid I2C addresses, up to 8 modules can share the I2C bus, providing up to 64 I/O ports in total.

Applications

The PCF8574T I/O Expansion Board can be used for:

• Arduino projects
• Raspberry Pi projects
• GPIO expansion
• LED control
• Push-button and switch interfaces
• Relay control
• Keypad interfaces
• Digital sensor interfacing
• Display control
• Home automation
• Robotics projects
• Industrial control prototypes
• IoT projects
• Embedded system development

Package Includes

• 1 × PCF8574T I2C I/O Extension Board

Product Disclaimer

• The module is an I2C digital I/O expansion board and does not function as an analog input expansion board.
• The maximum number of modules depends on the available and configurable I2C addresses of the specific PCF8574 variant and board design.
• Ensure that the connected devices operate within the electrical limits of the PCF8574T and the development board being used.
• Product images are for illustration and representation purposes only. The actual product may slightly differ in appearance, colour, design, or component placement from the images shown due to manufacturing variations and production batches.