---
title: "ECU – Single Ethernet Module"
url: "https://maker.wiznet.io/Lihan__/projects/ecu--single-ethernet-module/"
markdown_url: "https://maker.wiznet.io/Lihan__/projects/ecu--single-ethernet-module/md"
type: "UCC: User Created Content"
author: "Jan Vidar Berger"
author_url: "https://www.basicpi.org/2025/07/16/ecu-single-ethernet-module/"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "Jan Vidar Berger"
original_url: "https://www.basicpi.org/2025/07/16/ecu-single-ethernet-module/"
published: "2025-09-24"
language: "en"
likes: 0
views: 924
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# ECU – Single Ethernet Module

> Compact 10/100 Mbps ECU add-on that pairs an M33-class MCU with the W5500 TCP/IP Ethernet controller. Offers RJ-45 or rugged M12-4 connectors, low BOM cost and

Original author: Jan Vidar Berger (source: https://www.basicpi.org/2025/07/16/ecu-single-ethernet-module/)

## Article

### Project Overview

This module is a single-port Ethernet card for a modular ECU/PLC system. By embedding WIZnet’s W5500, the design gains a full TCP/IP stack in silicon, freeing the MCU for control tasks and keeping the BOM lean. Two connector footprints—industrial M12-4 and standard RJ-45—cover both harsh-environment and lab deployments.

### Key Features

**Embedded TCP/IP**: W5500 off-loads MAC/PHY and protocol handling, enabling deterministic 10/100 Mbps links over SPI.

**Dual Form-Factor Ports**: Board can be stuffed for either M12-4 or RJ-45 without schematic changes

**PoE-Ready**: Extra footprint allows a simple PoE front-end so the ECU can be powered through the Ethernet cable

**M12 Connector [**[**Link**](https://www.attend.com.tw/en/news.php?act=view&id=89#:~:text=Primarily%20used%20for%20DC%20power%20applications%2C%20T%2Dcoded,sensors%2C%20and%20other%20devices%20in%20industrial%20environments)**]: **M12 connectors are robust, circular connectors They come in 2- to 17-pin configurations for data or power applications

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## What is an ECU?

**ECU (Electronic Control Unit)**
→ A **small computer (controller)** embedded in vehicles or industrial equipment.
→ It takes sensor inputs, performs **computations**, and controls actuators (motors, valves, lights, etc.).

In simple terms, it is the **“electronic brain” responsible for a specific function**.

## Where are ECUs used?

**Automotive** 🚗

Engine/Transmission control, ABS/ESP, Body control (doors, lighting), ADAS/Autonomous driving

**Industrial / Special Vehicles** 🚜

Construction machinery, agricultural machines, forklifts → hydraulic and work equipment control

**Industrial Automation** 🏭

Robots, motor drives, sensor hubs → factory automation systems

**Marine / Aerospace** 🚤✈️

Boat engines/navigation, drones, aircraft flight controllers

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### Network Architecture

Module plugs into ECU back-plane.
upstream switch delivers power (if PoE) and network. For time-critical traffic multiple single-port boards can be replaced by the author’s upcoming dual-/triple-port variants, but for event-driven UDP telemetry this board is sufficient.

### Lessons Learned

Access to the MAC layer is required for hard-real-time protocols like EtherCAT.
W5500’s closed MAC limits this, but for UDP/HTTP it excels.

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Source: https://maker.wiznet.io/Lihan__/projects/ecu--single-ethernet-module/