Unit ChainBUS (STM32G031)

2026-02-06T13:10:13+00:00

Price: 4.30

The M5Stack Unit ChainBus is a Chain-series protocol conversion module with an STM32G031G8U6 and UART daisy-chaining for multi-device setups. It supports Chain UID/version queries and Unit expansion via I2C, GPIO, ADC sampling and NVIC interrupt management for unified control.

The M5Stack Unit ChainBus is a communication protocol conversion unit for the M5Stack Chain series, designed to simplify connecting and managing multiple devices on a single bus. It integrates an STM32G031G8U6 controller and uses a UART daisy-chain communication protocol, allowing multiple Chain devices to be linked together in a chained setup. It also supports multiple protocol interface conversions, making it possible to expand different peripherals on the same bus while enabling both hardware control and data interaction.

The left and right UART interfaces are used for connecting Chain series modules, supporting functions such as device UID queries, version queries, linked device enumeration, heartbeat communication, and more. A top multifunction expansion interface is included for connecting Unit series devices, supporting I2C communication control, GPIO input/output management, ADC sampling, and NVIC interrupt management.

With its unified bus control approach, Unit ChainBus is well suited to industrial control, IoT, smart home, and other applications where multiple devices need to be managed reliably through one communication system.

Features

STM32G031G8U6 core controller

UART daisy-chain communication protocol, supporting single / multiple Chain series devices in a chained connection

1 x RGB LED for status indication

1 x HY2.0-4P multifunction expansion interface for extending Unit series devices

2 x HY2.0-4P UART interfaces for extending Chain series devices

Development Platform

UiFlow2

Arduino

Specifications

MCU | STM32G031G8U6
Interface | 2 x HY2.0-4P UART Interfaces, 1 x HY2.0-4P Multifunction Expansion Interface
RGB LED | 1 x WS2812
Communication | UART 115200bps @ 8N1
Chain Protocol | Chain Bus UART daisy-chain communication protocol
Chain Features | Device UID query, version query, link device enumeration, heartbeat, etc.
Expansion I/O | I2C communication control, GPIO management (including interrupt configuration and status query), ADC sampling, NVIC interrupt management
Power Consumption | RGB white light max brightness 3.3V@17.72mA
Product Size | 29.8 x 24.0 x 8.0mm
Product Weight | 5.9g

Resources

Documents

Package Contents

1x Unit ChainBUS

2x HY2.0-4P Grove Cable (5cm)