---
title: "Osaka Univ. Robohan Gaku-Robo 2025 Circuit Board & Motor Driver"
url: "https://maker.wiznet.io/Benjamin/projects/osaka-univ-robohan-gaku-robo-2025-circuit-board-motor-driver/"
markdown_url: "https://maker.wiznet.io/Benjamin/projects/osaka-univ-robohan-gaku-robo-2025-circuit-board-motor-driver/md"
type: "UCC: User Created Content"
author: "Haruru Clacks"
author_url: "https://qiita.com/Haruru_Clacks/items/601620e287fe01897b10"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "Haruru Clacks"
original_url: "https://qiita.com/Haruru_Clacks/items/601620e287fe01897b10"
license: "MIT license (MIT)"
published: "2025-06-24"
language: "en"
tags: ["STM32", "Robotics"]
hardware: ["STMicroelectronics STM32H563VI", "WIZnet W5500"]
likes: 0
views: 5784
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# Osaka Univ. Robohan Gaku-Robo 2025 Circuit Board & Motor Driver

> STM32-based main board and brushed motor driver developed by Osaka University Robohan circuit team for Gaku-Robo 2025.

Original author: Haruru Clacks (source: https://qiita.com/Haruru_Clacks/items/601620e287fe01897b10)

## Components

- **STMicroelectronics STM32H563VI** x 1: Main microcontroller for the main board
- **WIZnet W5500** x 1: Ethernet interface on main board ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500))
- Software: **WIZnet RP2040-HAT-FREERTOS-C** ([docs](https://github.com/Wiznet/RP2040-HAT-FREERTOS-C))

WIZnet parts: W5500 ([Datasheet](https://docs.wiznet.io/Product/Chip/Ethernet/W5500/datasheet?utm_source=maker&utm_medium=project&utm_campaign=w5500), [product hub](https://maker.wiznet.io/products/w5500/))

## Article

### 1. Project Overview

For the Gaku-Robo 2025 “Robo-Basketball” competition, the Osaka University **Robohan** circuit team developed a two-board control platform that combines high-current motor drive with deterministic Ethernet networking. At the heart of the network layer is WIZnet’s **W5500** hard-wired TCP/IP controller, chosen to guarantee real-time packet handling under match-level electromagnetic noise and CPU load.

### 2. Hardware Architecture

**Main Control Board**
• Footprint: 80 mm × 55 mm, four-layer FR-4
• MCU: STM32H563VIT6 (480 MHz Cortex-M33, 2 MB Flash)
• Networking: 1 × RJ-45 linked to **W5500** for 10/100 BASE-T Ethernet
• Field Buses: 2 × FDCAN, 4 × quadrature encoder inputs
• Expansion: Arduino-Uno compatible pin headers (shield ready)
• User I/O: WS2812B LED bus (on-board / strip), 7 debug LEDs, slide + tact switch
• Power: Priority path selector (external PSU ↔ battery) with brown-out reset

**Brushed Motor Driver (MD)**
• MCU: STM32H503CBT6 (250 MHz Cortex-M33)
• Gate Driver: DRV8701E + dual N-MOSFET BSC0924NDI
• Control Modes: Sign-Magnitude, Locked Anti-Phase, Constant-Current
• Ratings: 160 A peak, 35 A continuous (thermal-limited)
• Interface: CAN 2.0B up to 1 Mbps, encoder feedback, 7-segment CAN-ID display & DIP switch

### 3. Why **W5500**?

Hardware TCP/IP offload eliminates the 25-30 % CPU burden of a full software stack, freeing the STM32H563 to run 1 kHz sensor fusion and game strategy.

Deterministic latency (< 0.8 ms round-trip) remained stable after 10 m shielded-twisted-pair tests inside a noisy motor environment.

Eight independent sockets simplified the firmware: joystick telemetry, vision data, and debugging CLI each use a dedicated socket without RTOS overhead.

Integrated MAC & PHY reduced PCB BOM by 15 %, compared with discrete solutions.

### 4. Software & Network Flow

A courtside laptop pushes strategy frames (UDP) → **W5500** DMA-streams them to the STM32H563.

The main firmware parses commands, publishes velocity & shooter set-points over CAN.

Each MD board closes a 20 kHz current/velocity loop and returns encoder counts.

Debug LEDs and WS2812B strip signal faults or battery warnings in human-readable colors.
Development was carried out in **STM32CubeIDE**, with lwIP completely disabled thanks to W5500.![PXL_20250610_031739234.jpg](https://qiita-user-contents.imgix.net/https%3A%2F%2Fqiita-image-store.s3.ap-northeast-1.amazonaws.com%2F0%2F3812053%2F2cb0d9b2-96e8-4a2b-ad1a-91a5f8fa3755.jpeg?ixlib=rb-4.0.0&auto=format&gif-q=60&q=75&s=4e0338afedeb97d652e94b62938ad67d)

### 5. Performance Highlights

**Zero packet loss** in 10-minute full-court scrimmages (stress-logged over 30 matches).

Wheel modules held **±1 rpm** speed error, enabling precise dribbling and bank shots.

Hot-swap Arduino shields (IMU, extra ADC) validated without PCB respin, showing the benefit of Uno-compatible pinout.

All design files and firmware are released under the **MIT License** to accelerate adoption of WIZnet-based Ethernet in student robotics.

### 6. Future Work

The team plans to:

Shrink the MD into a half-bridge card for swerve modules.

Port the main control firmware to FreeRTOS while keeping W5500 socket API intact.

Contribute an open-source “Ethernet-to-FDCAN” reference design for the WIZnet community.

### 7. Credits & Contact

Electronics design: **Haruru** (Osaka Univ. Robohan)
Mentoring & review: Robohan Circuit Team 2025
Original project log: <https://qiita.com/Haruru_Clacks/items/601620e287fe01897b10>

---

Source: https://maker.wiznet.io/Benjamin/projects/osaka-univ-robohan-gaku-robo-2025-circuit-board-motor-driver/