Contributing to Bubba Machine

Thanks for wanting to help. Bubba Machine is free firmware for the M-VAVE FM-1 and every bit of help counts: testing in the emulator, reporting bugs, improving the manual, designing sounds or writing code.

You can write in English or Spanish.

Ways to help

• Test and report. Use the web emulator and open an issue with what happened, what you expected and how to reproduce it. Screenshots help a lot.
• Interface ideas. Open an idea issue. The current direction is in DESIGN_3.0.md.
• Documentation. The manual lives in docs/en/MANUAL.md (and the Spanish one in docs/MANUAL.md); the website is generated from the .md files.
• Code. Read DEVELOPMENT.md to build and test.
• Hardware. If you have an FM-1 and experience with the JieLi SDK, the port in hal/fm1/ is what needs help the most.

Code rules

1. All code is our own. Do not copy, translate or paraphrase code from other FM-1 firmwares (including Felucca). Hardware facts (pins, timings, documented registers) can be used, citing the source in docs/SPEC_V3.md.
2. Third-party code only with a GPL-3.0-compatible license, and listed in the credits.
3. Sounds: only synthesized in tools/, made by you, or under a free compatible license (CC0, CC-BY or GPL). No samples from records or commercial packs. To test with third-party audio use assets/loops/loops.local.json, which is never pushed.
4. Dependency-free C99 in core/: no malloc, no floating point in the audio path and nothing that depends on the hardware. Everything hardware-related goes in hal/.
5. Every new file starts with the license identifier:

/* SPDX-License-Identifier: GPL-3.0-or-later
 * Copyright (C) 2026 Your Name */

Before opening a pull request

Pull requests go to the dev branch. From there changes move to qa to be tested and then to main, which is what is released (see branches).

• ☐ py -3 tools/build.py test passes with no failures.
• ☐ If you changed the interface, the screenshots (assets/screens/) and the manual are updated.
• ☐ If you changed the pattern or flash format, it is explained in the PR and in the changelog.
• ☐ If you added anything third-party, it is in the credits.

License of contributions

By submitting a contribution you agree that it is published under the project's license, GPL-3.0-or-later. We recommend signing your commits with git commit -s (Developer Certificate of Origin) to record that you have the right to contribute that code.

Conduct

This project follows a code of conduct.

This page is generated from docs/en/CONTRIBUTING.md. Spotted a mistake? Edit the file and send a pull request.