Description

Bare PCB For CH390H SPI to Ethernet Controller Module

Product Overview

The CH390H SPI to Ethernet Controller Bare PCB is a compact DIY development board designed for building a 10/100 Mbps Ethernet interface for microcontrollers through SPI.

This product is supplied as an unassembled bare PCB, allowing users to source and solder the required components themselves. The PCB provides footprints for the CH390H Ethernet controller, 25 MHz crystal, Ethernet transformer/RJ45 interface, capacitors, resistors, status LEDs, and SPI header.

It is a suitable choice for electronics enthusiasts, embedded developers, and students who want to build and experiment with their own SPI-based Ethernet interface.

Key Features

• CH390H Ethernet Controller
• SPI host interface for connection to an external MCU
• 10/100 Mbps Ethernet interface
• Integrated Ethernet PHY functionality
• Standard RJ45 Ethernet connector with integrated magnetics
• 25 MHz crystal oscillator
• Dedicated INT interrupt output
• Onboard Ethernet status LEDs
• Compact PCB design
• Clearly labeled SPI interface
• Designed for 3.3 V logic
• Suitable for Arduino, STM32, ESP32, and other MCU platforms with SPI
• No external Ethernet PHY is required when using the complete module

The WCH product family includes dedicated Ethernet controllers and PHY/interface devices intended for embedded connectivity applications.

SPI Interface

The module provides a 7-pin header for direct connection to an MCU:

Typical MCU Connection

The CS, SCK, MOSI and MISO signals form the SPI communication interface, while INT can be connected to an MCU GPIO for Ethernet event/interrupt handling.

Ethernet Interface

The board uses an RJ45 Ethernet connector with integrated magnetics.

The Ethernet section includes:

• RJ45 connector
• Integrated Ethernet transformer/magnetics
• Ethernet differential-pair connections
• Ethernet link/activity LEDs
• 75 Ω termination network
• CH390H Ethernet interface

The RJ45 connector provides a standard physical Ethernet connection for connecting the MCU system to an Ethernet switch, router, PC, or other Ethernet-enabled equipment.

Technical Specifications

Note: The exact electrical limits, SPI timing, supported Ethernet modes, and controller operating conditions should be taken from the CH390H datasheet for the specific chip revision being used.

Onboard Components

The PCB includes the main circuitry required for the Ethernet interface:

• CH390H Ethernet controller
• 25 MHz crystal oscillator
• Ethernet RJ45 connector with integrated transformer
• Decoupling capacitors
• Ethernet termination components
• SPI interface header
• Ethernet status LEDs
• 3.3 V power connections

Applications

The CH390H SPI Ethernet Module can be used in many embedded applications, including:

• STM32 Ethernet expansion
• ESP32 Ethernet applications
• Arduino Ethernet projects
• Industrial controllers
• PLC and automation projects
• Embedded web servers
• Remote monitoring systems
• IoT gateways
• Network-connected sensors
• Data acquisition systems
• Robotics
• Custom development boards
• Ethernet-to-MCU communication systems

It is particularly useful when the selected MCU does not have a convenient Ethernet interface or when you want to keep the Ethernet hardware separate from the main controller board.

Why Use SPI Ethernet?

One of the main advantages of this design is that the MCU only needs an SPI interface plus one interrupt GPIO to communicate with the Ethernet controller.

This allows Ethernet connectivity to be added to many low-cost microcontrollers without requiring a dedicated Ethernet MAC interface on the MCU.

For example:

Package Contents

• 1 × CH390H SPI to Ethernet Controller PCB

Notes

• 3.3 V supply is required for the module.
• Connect the module’s GND to the MCU GND.
• The SPI signals should be connected according to the MCU’s SPI peripheral configuration.
• The INT pin is optional depending on the software implementation, but using it allows interrupt-driven Ethernet communication.
• MCU firmware/library support is required to communicate with the CH390H.
• This product is an Ethernet controller module, not a standalone Ethernet-to-USB adapter.
• Ethernet cable and MCU are not included unless specifically stated.