---
title: "[RE] x65"
url: "https://maker.wiznet.io/irina/projects/re-x65/"
markdown_url: "https://maker.wiznet.io/irina/projects/re-x65/md"
type: "UCC: User Created Content"
author: "Jaroslav Sykora"
author_url: "https://github.com/jsyk/x65/"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "Jaroslav Sykora"
original_url: "https://github.com/jsyk/x65/"
published: "2025-05-28"
language: "en"
likes: 0
views: 1562
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# [RE] x65

> X65 is a modern retro computer using 65C02/65816 CPUs, VERA FPGA for video/audio, and Wiznet W6100 for full IPv4/IPv6 Ethernet networking support.

Original author: Jaroslav Sykora (source: https://github.com/jsyk/x65/)

## Article

## 🔎 Overview

The [X65 Project](https://github.com/jsyk/x65) is a modern take on the classic retro computer, built around the **WDC 65C02** or **65C816** microprocessor. It blends the charm of 8/16-bit computing with modern features like **Ethernet networking**, **FPGA-based video/audio**, and **Python-based debugging tools**—making it an ideal platform for firmware developers, RTL designers, retro computing enthusiasts, and embedded systems engineers.

---

## ⚙️ Hardware Specifications

| Component | Description |
| --- | --- |
| **CPU** | W65C02S (8-bit) or W65C816S (16-bit) |
| **Memory** | 2MB SRAM with memory banking via RAMBLOCK/ROMBLOCK registers |
| **Video Output** | VERA FPGA (open-source, VGA-compatible, 128KB VRAM) |
| **Audio Output** | PCM, PSG, and FM synthesis (YM2151 via Verilog – AURA module) |
| **Networking** | Wiznet **W6100** – Hardware TCP/IP Stack with IPv4/IPv6 support |
| **I/O Ports** | PS/2 keyboard & mouse, SD card, USB device, Ethernet, UEXT connector |
| **Board Format** | 4-layer PCB single-board computer (SBC) |

---

## 🌐 Ethernet on X65 – Powered by Wiznet W6100

The X65 integrates a **Wiznet W6100 Ethernet controller**, which brings full-stack hardware networking capabilities into the 8/16-bit computing realm.W6100 Highlights:

**10/100 Mbps Ethernet**

Supports both **IPv4 and IPv6Hardware TCP/IP Stack** (TCP, UDP, ICMP, IGMP)

Simplified microprocessor interface

Integrated into X65 through memory-mapped I/O and Verilog-defined interface logic via the NORA FPGA

### Use Cases on X65:

Remote debugging via Ethernet

Lightweight web server or client using W6100 stack

TFTP booting and network-based development

IoT-style communication from a 65C816 system

---

## 🧠 Memory & System Architecture

The 65C02 uses a 64KB address space, while the 65C816 supports a 24-bit address bus (16MB max).

The X65 system implements **bank switching** via `RAMBLOCK` and `ROMBLOCK` control registers.

The VERA video/audio module and W6100 are mapped into the I/O space for efficient access.

For detailed memory map documentation, see:
👉 [Memory Map Doc](https://github.com/jsyk/x65/blob/main/doc/mem-map.md)

---

## 🎮 Video & Audio Subsystem

**VERA FPGA**: Provides high-resolution VGA video and PSG-style sound.

**AURA (YM2151 FPGA)**: A cycle-accurate FM synthesis implementation using Verilog, enabling arcade-quality audio from a classic CPU.

![](https://maker.wiznet.io/upload/ckeditor5/872661155%5F1748444355%2Epng)

---

## 🔧 Debugging and Development Tools

**Python-based host CLI tools**: Interact with X65 memory, I/O, and firmware uploads directly from your PC.

**USB-C debug interface**: Supports in-circuit debugging and quick firmware flashing.

---

## 🧪 Why X65 Matters

X65 isn’t just a retro machine—it’s a fully capable **hardware-software co-design platform** for engineers and makers. Whether you’re:

Exploring WDC-based assembly programming

Writing bare-metal firmware with memory-mapped peripherals

Testing custom Verilog modules in a live system

Implementing embedded networking via Wiznet’s W6100

…the X65 can be your hands-on lab.

![](https://maker.wiznet.io/upload/ckeditor5/872661155%5F1748444371%2Epng)

---

## 📂 Related Repositories

🔩 [x65-mech](https://github.com/jsyk/x65-mech): Mechanical design files (case, mounting, layout)

🎮 [VERA module](https://github.com/commanderx16/vera-module): Video & audio FPGA engine

🎵 [AURA (YM2151 Verilog)](https://github.com/jsyk/aura): FM synthesizer in HDL

---

## 📈 SEO Tags (for metadata)

`X65 retro computer, WDC 65C02 65C816, Wiznet W6100 ethernet, FPGA computer, Python firmware debugger, YM2151 FPGA, VERA video, Verilog SBC, maker retro CPU, 8bit 16bit SoC`

---

## ✅ Final Thoughts

The X65 project is a one-of-a-kind blend of retro CPU charm and modern embedded systems engineering. It's open-source, highly hackable, and perfect for WIZnet-powered networking experiments. With the **W6100**, engineers can bring vintage processors into the modern web-enabled world.

👉 Check out the full project: [GitHub - jsyk/x65](https://github.com/jsyk/x65)

**Keywords**: 65C02, 65C816, retro computer, W6100 Ethernet, FPGA SBC, Python debugger, VERA, YM2151, WDC CPU, X65 board, Verilog

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Source: https://maker.wiznet.io/irina/projects/re-x65/