---
title: "Dual Ethernet Port Expansion for SP2302 Using WIZ850io (W5500)"
url: "https://maker.wiznet.io/Benjamin/projects/dual-ethernet-port-expansion-for-sp2302-using-wiz850io-w5500/"
markdown_url: "https://maker.wiznet.io/Benjamin/projects/dual-ethernet-port-expansion-for-sp2302-using-wiz850io-w5500/md"
type: "UCC: User Created Content"
author: "SecurePi"
author_url: "https://hackaday.io/page/399465-dual-ethernet-port-expansion-for-sp2302-using-wiz850io-w5500"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "SecurePi"
original_url: "https://hackaday.io/page/399465-dual-ethernet-port-expansion-for-sp2302-using-wiz850io-w5500"
license: "Apache License 2.0 (Apache-2.0)"
published: "2025-05-29"
language: "en"
tags: ["W5500"]
hardware: ["WIZnet WIZ850io"]
likes: 0
views: 2756
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# Dual Ethernet Port Expansion for SP2302 Using WIZ850io (W5500)

> Enable dual Ethernet on SP2302 board using WIZ850io (W5500) module via SPI interface. Perfect for industrial IoT and secure networking applications.

Original author: SecurePi (source: https://hackaday.io/page/399465-dual-ethernet-port-expansion-for-sp2302-using-wiz850io-w5500)

## Components

- **WIZnet WIZ850io** x 1 ([docs](https://docs.wiznet.io/Product/ioModule/WIZ850io))

## Article

### **Overview**

In today's interconnected world, single-board computers often need multiple network interfaces for advanced applications such as network segmentation, firewall implementation, or redundant connectivity. This project transforms the Secure Pi SP2302 into a powerful dual-Ethernet platform using WIZnet's WIZ850io module, opening new possibilities for industrial IoT and secure networking applications.

### **🎯 Why Dual Ethernet Matters**

Traditional single-board computers typically come with only one Ethernet port, limiting their use in:

- **Network Isolation**: Separating trusted internal networks from untrusted external connections

- **Gateway Applications**: Acting as a bridge between different network segments

- **Redundancy**: Maintaining connectivity even if one network fails

- **Load Balancing**: Distributing network traffic across multiple interfaces

- **Industrial Control**: Connecting to both control and monitoring networks simultaneously

### **🔧 Hardware Implementation**

The WIZ850io module, powered by the W5500 chip, provides a complete hardware TCP/IP stack with SPI interface. This approach offers several advantages:

**Key Connections:**

- **SPI Communication**: MISO, MOSI, SCLK, and CS pins for high-speed data transfer

- **Control Signals**: Reset and interrupt pins for reliable operation

- **Power**: 3.3V supply shared with SP2302 for simplified power management

The beauty of this solution lies in its simplicity - just 8 wires connect the two boards, yet provide full Ethernet functionality without burdening the main processor.

### **💻 Software Architecture**

Our custom dual-port firmware seamlessly integrates the W5500 into the Linux ecosystem:

**1. Driver Integration**

- Native SPI driver support for W5500

- Automatic device recognition as eth1

- Full integration with Linux networking stack

**2. Network Management**

- Netplan configuration for modern network setup

- Support for both DHCP and static IP configurations

- Independent operation of both interfaces

**3. System Integration**

- Udev rules for consistent device naming

- Automatic initialization on boot

- Compatible with standard Linux networking tools

### **📋 Step-by-Step ImplementationPhase 1: Hardware Setup**
Connect the WIZ850io to your SP2302 following the pin mapping table. Ensure solid connections and proper grounding to avoid communication issues.

**Phase 2: Firmware Installation**
Flash the provided dual-Ethernet firmware image to enable W5500 support. This custom firmware includes all necessary drivers and configurations.

**Phase 3: Network Configuration**
Use netplan to configure your network settings. The system supports various configurations:

- Dual DHCP for automatic setup

- Mixed DHCP/Static for specific requirements

- VLAN support for advanced networking

**Phase 4: Verification**
Test both interfaces independently using standard Linux tools like ping, ifconfig, and ip commands.

### **🚀 Real-World ApplicationsIndustrial IoT Gateway**

- Connect to both operational technology (OT) and information technology (IT) networks

- Maintain security isolation while enabling data flow

**Network Security Appliance**

- Build custom firewalls or intrusion detection systems

- Monitor traffic between network segments

**Edge Computing Platform**

- Process data from isolated sensor networks

- Forward filtered results to cloud services

**Development and Testing**

- Create network testing environments

- Simulate complex network topologies

### **🔍 Troubleshooting TipsCommon Issues and Solutions:**

1. **W5500 Not Detected**: Check SPI connections and ensure proper power supply

2. **No IP Address on eth1**: Verify netplan configuration and DHCP server availability

3. **Intermittent Connection**: Review power stability and cable quality

4. **Performance Issues**: Optimize SPI clock speed for your application

### **📊 Performance Considerations**

The W5500 provides:

- Up to 80 Mbps throughput

- Hardware TCP/IP offloading

- Low CPU usage for network operations

- 32KB internal buffer for efficient packet handling

### **✅ Summary**

This project successfully demonstrates how to expand the SP2302's networking capabilities using the WIZ850io module. With minimal hardware modifications and our custom firmware, you can transform a single-port device into a versatile dual-Ethernet platform suitable for professional applications.

Whether you're building an industrial gateway, developing network security solutions, or simply need redundant connectivity, this solution provides a reliable and cost-effective path forward. The combination of SP2302's processing power and W5500's hardware networking engine creates a powerful platform for your next IoT or networking project.

**Get started today and unlock the full potential of your SP2302!**

---

Source: https://maker.wiznet.io/Benjamin/projects/dual-ethernet-port-expansion-for-sp2302-using-wiz850io-w5500/