Wiznet makers

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]: M12 connectors are robust, circular connectors They come in 2- to 17-pin configurations for data or power applications

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

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.