---
title: "RAK3272-SiP and W5500 Ethernet controller"
url: "https://maker.wiznet.io/jakelee/projects/rak3272-sip-and-w5500-ethernet-controller/"
markdown_url: "https://maker.wiznet.io/jakelee/projects/rak3272-sip-and-w5500-ethernet-controller/md"
type: "UCC: User Created Content"
author: "Fulvio Spelta"
author_url: "https://forum.rakwireless.com/t/rak3272-sip-and-w5500-ethernet-controller/11829"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "Fulvio Spelta"
original_url: "https://forum.rakwireless.com/t/rak3272-sip-and-w5500-ethernet-controller/11829"
published: "2025-12-16"
language: "en"
hardware: ["RAK3272-SiP Breakout Board", "WIZnet W5500"]
likes: 0
views: 278
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# RAK3272-SiP and W5500 Ethernet controller

> Discussion about using RAK13800_W5100S Arduino library while building RAK3272-SiP-based module with W5500 to handle dual communication channels using SPI.

Original author: Fulvio Spelta (source: https://forum.rakwireless.com/t/rak3272-sip-and-w5500-ethernet-controller/11829)

## Components

- **RAK3272-SiP Breakout Board** x 1
- **WIZnet W5500** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500))

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

### **🔎 Context**

The original poster wanted to build a **custom RAK3272-SiP-based module** with a **W5500 Ethernet controller** to handle dual communication channels using SPI. They tried using the **RAK13800_W5100S Arduino library** (designed for the W5100/W5100S) but ran into problems: detection works, but the system **hangs after **`**Ethernet.begin()**`, both in DHCP and static IP modes.

---

### **🧪 What Happened**

#### **1. Initial Setup & Symptoms**

The setup includes the RAK3272-SiP connected to a W5500 module over SPI.

The Arduino sketch detects the module (via SPI); if it’s not present it reports “no module”.

However, once `Ethernet.begin(mac)` is called, the code **stalls during Ethernet initialization** — seemingly hanging during the Wiznet reset/init sequence.

---

### **🔧 Wiring & Pins DiscussionThe OP wired only the 4 core SPI lines** (MOSI, MISO, SCLK, CS).

They asked whether other pins (like **reset or interrupt) need to be connected** for the library to work properly instead of just the 4 SPI pins.

![image](https://forum.rakwireless.com/uploads/default/optimized/2X/e/eaf55559be8bccdbc27f9de3fa9f9c176f5a3e10_2_690x377.jpeg)

---

### **🗣️ Community Guidance & Insights**

Another contributor warned that **pin conflicts** on the RAK3272-SiP can occur if multiple peripherals share the same pins — especially when adding custom hardware. Confirming correct SPI and CS wiring is essential.

It was noted that in WisBlock modules (e.g., RAK13800 Ethernet modules using W5100) additional signals like **Reset (RSTn) and Interrupt (INTn)** play a role, and the equivalent pins should be mapped appropriately when using W5500.

One responder posted the **RAK3272-SiP pin definitions** from the Arduino core (mapping SPI and general I/O), helping clarify which SiP pins correspond to the SPI signals used.

---

### **🧠 Troubleshooting & Outcome**

After incorporating advice, the OP attempted further hardware tests using a breadboard to verify wiring.

They modified the Wiznet driver code with additional debug prints and found that the initialization **appeared to hang inside the Wiznet soft-reset routine**.

At the time of the last update in the thread, the OP mentions **no working solution yet** and plans to try a W5100S-based board next, suspecting the library might not fully support the W5500 in this context.
![image](https://forum.rakwireless.com/uploads/default/optimized/2X/7/7e152f7dda0430ab758777910495c1baf8e2aca0_2_469x500.jpeg)
![image](https://forum.rakwireless.com/uploads/default/original/2X/4/4a91a3d252372e6adb1158305a8bfaa338a3dd95.png)

---

Source: https://maker.wiznet.io/jakelee/projects/rak3272-sip-and-w5500-ethernet-controller/