The BMB22M301 is a UART-to-RS485 bridge module designed for long-distance and multi-device communication scenarios such as automation equipment, sensor networks, and smart agriculture. Simply plug in the module, and your original controller board—previously limited to short-distance communication—instantly transforms into a powerful RS485 communication hub!
Whether you're using an Arduino, BMduino, or other development boards, as long as it has a UART interface, you can easily integrate the BMB22M301 to upgrade to an RS485 system for remote data transmission and real-time monitoring.
The BMB22M301 is a UART-to-RS485 bridge module designed for long-distance and multi-device communication scenarios such as automation equipment, sensor networks, and smart agriculture. Simply plug in the module, and your original controller board—previously limited to short-distance communication—instantly transforms into a powerful RS485 communication hub!
Whether you're using an Arduino, BMduino, or other development boards, as long as it has a UART interface, you can easily integrate the BMB22M301 to upgrade to an RS485 system for remote data transmission and real-time monitoring.
Optional 120Ω termination resistor via jumper for improved signal integrity
Product Description
The BMB22M301 is a UART-to-RS485 bridge module.
UART (commonly seen as TX/RX on Arduino or BMduino boards) is typically used for short-distance, point-to-point communication. With this module, you can upgrade a basic UART interface into an industrial-grade RS485 interface suitable for long-distance applications.
Just a few simple connections and a control pin for switching transmission modes are all you need to get started—making it ideal for beginners, students, and developers. For example, if you want to interface with the BM25S2621-1 soil sensor module, simply connect the BMB22M301 in between, and your controller can easily read soil humidity and temperature data—perfect for smart irrigation or environmental monitoring.
Main Functions
UART ⇄ RS485 Bidirectional Conversion: Enables RS485 communication on UART-only controller boards.
High-Speed Transmission: Supports data rates up to 1000kbps for real-time data exchange.
Multi-Device Connectivity: Connect up to 256 RS485 devices—ideal for large-scale deployments.
Low Power Consumption: Consumes just 2.5mA in receive mode—great for long-term applications.
Selectable Termination Resistor: Built-in 120Ω jumper switchable as needed.
Simple Control: Use the STA pin to switch between transmit and receive modes.
How to Use
Wiring Instructions:
- Connect the module’s TX/RX to the controller board’s RX/TX (note: TX to RX, RX to TX)
- Connect the power supply (supports 3.0V ~ 5.5V)
- Connect A/B pins to the RS485 device (A to A, B to B)
- STA pin is controlled by the MCU to toggle between transmit and receive modes
Mode Switching:
- STA = High (1): Transmit mode
- STA = Low (0): Receive mode
Termination Resistor Setup (optional):
- For long-distance or multi-device setups, enable the 120Ω termination resistor by shorting the jumper
- For short connections or minimal devices, disable the jumper to reduce power consumption
⬥ For detailed usage instructions, please refer to the datasheet.
