Waveshare 2-Channel RS485 UART-RS485 SP3485 module for Raspberry Pi Pico

The Waveshare 2-Channel RS485 UART-RS485 SP3485 module for Raspberry Pi Pico provides two independent half-duplex RS485 ports using SP3485 transceivers and a UART interface compatible with the Pico's serial pins. The module enables differential serial communication over longer distances and in electrically noisy environments by converting UART signals to RS485 differential pairs. Its compact board layout is intended to extend Raspberry Pi Pico projects that require multi-node serial links, sensor networks, or industrial-style wiring.

Advantages

This module offers two RS485 channels on a single board, allowing simultaneous connection of multiple differential serial lines without additional transceivers. The use of SP3485 transceivers ensures TTL-to-RS485 conversion optimized for half-duplex communication. Designed for direct connection to Raspberry Pi Pico UART pins, the module simplifies wiring and integration into existing Pico projects. The board's compact form factor saves space on prototyping setups while providing reliable physical-layer conversion for extended-range serial connections.

Suitable for

• Connecting Raspberry Pi Pico to industrial sensors and actuators over RS485.
• Building multi-node serial networks such as Modbus RTU or custom protocols on a shared bus.
• Extending Pico UART connectivity over long cable runs in noisy environments.
• Prototyping systems that require two independent half-duplex RS485 links.

Key specifications

• Channels: 2 independent half-duplex RS485 ports.
• Transceiver type: SP3485 RS485 transceivers.
• Interface to host: UART-level signals compatible with Raspberry Pi Pico serial pins.
• Data direction: Automatic or TTL-controlled DE/RE as per board design (drive/receive control available).
• Signal type: Differential A/B pairs per channel for RS485 bus connection.
• Power supply: Low-voltage logic-compatible supply suitable for Pico (check board silk for exact voltage requirement).
• Mounting: Compact PCB suitable for prototyping and small enclosures.

How to use

Connect the module's UART TX/RX pins to the corresponding UART pins on the Raspberry Pi Pico and supply the board with the same logic voltage as the Pico. Terminate the RS485 bus with appropriate resistors at the ends of the cable if required by the network topology. Configure the Pico's UART peripheral for the desired baud rate and parity to match connected RS485 devices. Manage data direction either by using the module's automatic DE/RE control or by toggling the direction control pin from the Pico when deterministic direction control is needed.

Usage recommendations

For reliable RS485 communication, use twisted-pair shielded cable for A/B differential lines, enable proper bus termination at both ends, and ensure a single common reference or ground between nodes when required. Match UART settings across devices and avoid long unterminated stubs. If galvanic isolation is necessary in your application, consider adding an isolated transceiver or isolation stage since the module's isolation is not specified.