PGEZ PCA9671 GPIO Expander Zero

NEW For April2025! - Further details to follow.

PGEZ Zero is a new STEM Maker and Developer SDK board, based on an PCA9671 GPIO Expander wrapped in a compact mechanical Pi Zero form.

Introduction

During development of the IPEM PiHat and ESPuno Pi Zero, I required a different approach to humble PCF series GPIO Expanders, so I looked around with the key objectives:

• Requires to operate on 3V3 and 5V systems
• 5V Tolerant GPIOs
• Quasi-Bidirectional Ports
• High Pin Sink Current with Latched Output
• High Total Sink Current
• Wide range of I2C Device Addresses
• Hardware and Software Resettable
• 400 kHz or 1 MHz I2C Bus speed
• Defaults to Inputs on Power-Up

The result was the PCA9671 from NXP which although is a replacement for the PCF8575, offers so much more.

Once a suitable device was sourced, and little development options available to test with, I decided to make my own compact and flexible PCA9671 Dev Board.

With a view to making this design available, I developed this further into the PGEZ (PCA9671 GPIO Expander Zero), so others may use it too.

Uses

PGEZ Zero is ideal for:

• Educational and Classroom projects.
• Battery powered projects such as Robotics, Drones, Cars and Vehicles, Boats and University Projects.
• Farming and Agricultural Projects.
• Industrial applications, Test Systems and Development
• Compatible with the GROVE EcoSystem

**Supporting STEM Electronic Internet of Things & Home Automation Technology for Smart Energy Monitoring**

Design

The PGEZ Zero has been designed to be as flexible as possible, providing easy interfacing support to, and not exclusively:

• Raspberry Pi (and other flavours)
• Espressif ESP
• Arduino
• ARM
• STM32
• AVR
• Microchip PIC
• GROVE EcoSystem

Features

PGEZ Zero features the new PCA9671 GPIO Expander.

• PCF8575 Replacement
• 16 GPIO Ports (Inputs or Outputs)
• 64 I2C Addresses
• Selectable 3V3 or 5V
• GPIO 5V Tolerant Inputs
• Hardware and Software Resets
• Supports 400 kHz and 1 MHz I2C Bus
• Supported in development environments including:
• PlatformIO
• Arduino IDE
• Python
• C Libraries
• Others.

Libraries

[Rob Tillaart PCA9671](https://github.com/RobTillaart/PCA9671) (NEW)

Updates

23rd March 2025 - Design of PGEZ development board.

January 2025 - Concept for another project

GitHub

Further details and updates maybe also be found on my GitHub

Purchase

This new board will be available mid April on eBay.

Further Information

Additional information, and other technical details on this project, maybe found in the related repository pages.

Repository Folders

• Code(Code examples for Arduino IDE and Platform IO)
• Datasheets and Information(Component Datasheets, Schematics, Board Layouts, Photos, Technical Documentation)
• Certification(Related Repository Project or Part, Certification Information)

Repository Tabs

• Wiki (Related Repository Wiki pages and Technical User Information)
• Discussions (Related Repository User Discussion Forum)
• Issues (Related Repository Technical Issues and Fixes)

We value our Customers, Users of our designs and STEM Communities, all over the World. Should you have any other questions, or feedback to share to others, please feel free to:

Visit the related Project Repositories plus the related Discussions and Wiki Pages. See tab in each separate repository.

Project Community Information can be found at https://www.hackster.io/DitroniX

DitroniX.net Website - Contact Ushttps://ditronix.net/contact/

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LinkedIN: https://www.linkedin.com/in/g8puo/

Dave Williams, Maidstone, Kent, UK.

Electronics Engineer | Software Developer | R&D Support | RF Engineering | Product Certification and Testing | STEM Ambassador

STEM

Supporting STEM Learning

Life is one long exciting learning curve, help others by setting the seed to knowledge.

Should you have any thoughts, or have a challenging application and would like to beta test a board, please let me know.