My laptop is a modest Asus running Windows (Core i3, 8 GB of RAM).
I have Visual Studio Code installed, as well as SourceTree for source control.

For a previous project, I had installed MSYS2 (msys2.org) to develop a BASIC interpreter in C.
I thought that with all this in place, setting up a development environment for the Thomson MO5 would be easy… but not quite 😅

First attempts on Windows

According to forums, developing for Motorola 6809 processors requires installing two tools:

I therefore went looking for precompiled Windows versions, without much success.
These tools seem much more oriented toward Linux, so I tried installing them under MSYS2.

However, compiling CMOC did not go well:
there were many errors related to Linux-specific header files (sys/select.h, sys/wait.h, etc.), which are missing on Windows, even with MSYS.

Plan B: a Raspberry Pi as the development machine 🧠

Instead of installing WSL (a Linux environment under Windows), I chose to use my Raspberry Pi 4 — simpler and, above all, lighter.

I installed Raspberry Pi OS (Raspbian) using Raspberry Pi Imager, then enabled:

  • Wi-Fi
  • Samba
  • and SSH, to work remotely from my PC.

Then I connected to the Pi via SSH and installed the development tools:

sudo apt install build-essential bison flex git vim nano

Installing LWTOOLS

Download:

wget http://www.lwtools.ca/releases/lwtools/lwtools-4.24.tar.gz
tar -xzf lwtools-4.24.tar.gz
cd lwtools-4.24

Build and install:

make
sudo make install

Installing CMOC

Download:

wget https://freshcode.club/projects/cmoc/files/cmoc-0.1.93.tar.gz
tar -xzf cmoc-0.1.93.tar.gz
cd cmoc-0.1.93

Build and install:

./configure
make
sudo make install

Verification:

cmoc --version

Remote development with VS Code

To work comfortably, I installed the Remote - SSH extension in Visual Studio Code.
It allows me to connect directly to my Raspberry Pi and run compilation commands without leaving my editor.

Another advantage of Visual Studio Code is the ability to enable development agents such as GitHub Copilot or other AI assistants.

For a project as atypical as development on the Thomson MO5, these modern tools can prove invaluable — whether to generate C code, understand old concepts, or help optimize routines for the 6809 processor.

Testing and emulators

Before trying things on a real MO5, it’s better to test programs in an emulator.

  • Under Linux, several MO5 emulators are available.
  • Under Windows (my case), I chose DCMOTO (dcmoto.free.fr).

⚠️ Most of these sites are served over HTTP (not secure), which triggers some warnings in modern browsers.
But don’t worry: they are reliable historical references in the retro-computing world.

Configuration summary

🖥️ Windows:

  • Visual Studio Code + Remote - SSH extension
  • SourceTree (I like handling Git from a graphical environment — that’s my “Windows side” 😄)

🍓 Raspberry Pi 4 (Raspbian):

  • CMOC
  • LWTOOLS

💬 In short: to recapture the spirit of 8-bit development, I recreated a minimalist but functional environment based on a Raspberry Pi.
This setup will be used to compile and test my future programs for the Thomson MO5.