Chapter 17: Afterword

Acknowledgements

The X65 is the work of a small group of people and a much larger collection of shoulders to stand on. A few that deserve particular mention:

  • PCBWay, for sponsoring the manufacturing of the DEV-boards and delivering them with their characteristic quality.

  • zbyti, for writing Sokoban in MAD-Pascal and for being the first to put a real game on the platform.

  • Rumbledethumps and the picocomputer project, whose RP6502 / RIA lineage is visible throughout the X65’s firmware surface — the fastcall API, the monitor command shape, the HID handling.

  • Andre Weissflog (flooh), whose chips / chip-emulators toolbox and cycle-accurate 65Cxx core are the technical heart of Emu.

  • tildearrow, whose Sound Unit (tSU) fantasy-chip design is the architectural heart of the SGU-1. Without it, a custom X65 synth chip would have been a much slower and less coherent project.

  • Furmilion, from the Furnace Tracker community, for patient hands-on help bringing up and tuning the SGU-1 — testing register behavior, reporting quirks, suggesting fixes, and shaping the chip’s voice.

  • Android Arts, whose keyboard layout explorations (Famicube, Amiga770) inspired the X65 keyboard’s packed ortholinear top rows.

  • Every contributor who has filed a bug, answered a question in the community channels, or written a demo or utility for the DEV-boards.

Resources

All the X65 project material — code, documentation, community — is linked from the project website. The useful entry points:

Where

What it is

https://docs.x65.zone

This book

https://github.com/X65

The project GitHub organisation — firmware, schematic, examples, emulator, K816, cc65-dbg, OS/816, Furnace port

https://x65.zone/emu/

Web emulator (WebAssembly build of Emu)

https://x65.zone/news.html

Development blog — announcements, milestones, deep-dives

Matrix space #x65:chrome.pl

Real-time community chat

Core repositories

  • firmware — the authoritative implementation of the NORTH, SOUTH, and audio chips on RP2350 microcontrollers. The behavioural source of truth for this book.

  • schematic — KiCad project and PDF for the DEV-board.

  • examples — cc65 / ca65 starter projects, the x65.cfg linker config, and a growing library of example programs per subsystem.

  • emulator — the native and WebAssembly Emu builds.

  • K816 — the Rust high-level assembler used by OS/816.

  • cc65-dbg — the VS Code Debug Adapter Protocol extension for cc65 / ca65 workflows.

  • OS-816 — the operating system that boots on the X65 by default.

  • furnace — the X65 fork of Furnace Tracker with SGU-1 support.

Where the Project Is Now

At the time this book snapshot was written, the X65 is in the Gen2 DEV-board era: two RP2350s split as a NORTH / SOUTH pair, a dedicated audio RP2350 behind SOUTH, and the Raspberry Pi Radio Module 2 for Wi-Fi and Bluetooth. The SGU-1 sound chip is feature-complete — nine 4-operator FM channels with SID-style filtering, sweeps, and PCM playback, available in Emu and in the Furnace tracker. CGIA provides paletted and attribute modes plus HAM6 and affine, at a perfect 60 Hz over DVI-D. OS/816 has a working scheduler, COP-based syscalls, and a small shell; several of its intended subsystems (CIO, signals, bank allocator, system-wide lock registry) are designed and reserved but not yet implemented.

The long-term shape of the machine is the full computer: an all-in-one keyboard form factor with a custom 70 % keyboard (the 🐾 key at the Meta / Windows position), rear and side I/O, extra USB ports, and internal bays for storage — the Amiga / MSX lineage restated in modern parts. The DEV-boards currently in the field are Milestone 1: a platform for bring-up, for writing OS/816 and the first generation of software, for proving out each subsystem before they land in the full machine.

Book snapshots trail the code by design — for the current state of the work, the blog, Matrix space, and GitHub organisation linked in the Resources table above are the live sources.

Open-Source Contributions

Every part of the X65 — firmware, OS, emulator, toolchain, this book — is open source and accepts contributions. The usual paths in:

  • Bug reports on the GitHub repository that owns the behaviour: firmware for chip-level bugs, OS-816 for kernel bugs, examples for example-program bugs, and this book’s repository for documentation issues.

  • Pull requests for fixes or new features — start by opening an issue so the maintainer can flag whether the change fits the project direction before you spend time on it.

  • Example programs — concrete, small programs that demonstrate one feature well are some of the most valuable contributions, both for the examples repository and as blog-post material.

  • Music and graphics assets for shared demos and games — the SGU-1 + Furnace pipeline and the CGIA + image-converter tooling mean a composer or artist can contribute without touching 65C816 assembly.

If the idea is bigger than a single issue or PR, the Matrix space or Discord is the right place to have the conversation first.

That is the end of the book. Thank you for reading — and, if you build something on the X65, please consider sharing it with the community.