Dual Interface NIC - Proof of Concept

A cross-platform (x86 + ARM) network interface card using ESP32 with both USB-C and PCIe support.

Hardware Requirements

Minimal POC (USB-C Only - $12)

• ESP32-S3 DevKit with USB-C ($8)
• W5500 Ethernet Module ($4)
• Jumper wires

Full POC (USB-C + PCIe - $35)

• ESP32-S3 DevKit with USB-C ($8)
• W5500 Ethernet Module ($4)
• PCIe-to-USB Adapter Board ($15)
• USB-C breakout board ($5)
• Jumper wires ($3)

Architecture

Host Computer (x86/ARM)
    ↓
USB-C or PCIe Interface
    ↓
ESP32-S3 (Bridge Controller)
    ↓
W5500 Ethernet Controller
    ↓
Network

Pin Connections

ESP32-S3 to W5500 (SPI)

ESP32-S3    W5500
GPIO36   →  SCK
GPIO37   →  MISO
GPIO35   →  MOSI
GPIO34   →  CS
GPIO33   →  RST
3.3V     →  VCC
GND      →  GND

Interface Detection

GPIO2  →  PCIe Present Detection (pulled low when PCIe active)
GPIO15 →  USB-C CC1 Detection
GPIO12 →  Status LED (USB Active)
GPIO13 →  Status LED (PCIe Active)

Features

• ✅ Cross-platform: Works on x86 and ARM hosts
• ✅ Dual interface: USB-C and PCIe support
• ✅ Auto-detection: Automatically selects active interface
• ✅ Standard drivers: Uses CDC-ECM (no custom drivers needed)
• ✅ Hardware Ethernet: W5500 handles TCP/IP stack
• ✅ Hot-plug support: USB-C hot-pluggable

Supported Host Systems

• Linux (x86_64, ARM64, RISC-V)
• Windows 10/11 (x86_64, ARM64)
• macOS (Intel, Apple Silicon)
• Embedded Linux (Raspberry Pi, etc.)

Build Instructions

See docs/BUILD.md for detailed assembly instructions.

Firmware

See firmware/ directory for Arduino/ESP-IDF code.

Testing

See docs/TESTING.md for cross-platform testing procedures.