PurpleMonkey FM-1
A firmware for the M-VAVE FM-1 for a small child: press any key and something nice happens. Six-operator FM notes on a pentatonic scale, synthesised drums, a backing beat, four animal friends (Monkey, Cat, Dog, Llama) on a screen that moves with the music. No menus, nothing to save, nothing to break.
Status: a first public beta. It has been installed and runs on the owner's FM-1 (2026-10-09); most of what is checked was checked on the emulator. Before installing, read docs/PURPLEMONKEY.md, "Install, rollback". Installing firmware is at your own risk. Update mode is OCT- + OCT+ + HOME held 5 s.
Try it in the browser
https://quixotic7.github.io/PurpleMonkeyFM1/ (the site, once a release is published): the same firmware compiled to WebAssembly under "Try it first", the browser installer, the manual. Releases, and how one is made: BUILDING.md, "Releasing"; the notes are in docs/releases/.
Try it (Mac, no FM-1 needed)
pip3 install Pillow fonttools
brew install libraqm sdl2
sh tools/emu/build_pm.sh
build/host/pm_emu --front
| Computer key | FM-1 | PurpleMonkey |
|---|---|---|
A S D F G H J K L ; ' ] and W E T Y U O P, 2 3 4 5, F1..F4, Tab | the note keys | play |
F5 | FX | DRUMS |
F6 | SEL | SYNTH |
- | PLAY | BEAT on / off |
7 | HOME | knobs back to normal |
| Page Up / Page Down, then Up / Down | select a knob of SELECT, KNOB 1..4; turn it | PET, SPEED, BUSY, BOUNCE, SQUISH |
| mouse wheel over a knob | any knob, PRESETS and ALGORITHM too | SOUND, WORLD |
Every key and button can also be clicked. build/host/pm_emu --help has the full map and options
(tools/emu/README.md describes the emulator; it is ChoralRoot's, with PurpleMonkey's firmware in it).
What is here
| Path | What |
|---|---|
docs/PURPLEMONKEY.md | what it does, how it is built, where it differs from the brief, what was verified, budgets, open questions |
docs/UPSTREAM.md | the exact upstream revisions and every change made to imported files |
CLAUDE_HANDOFF.md | the brief |
firmware/src/pm_*.c, purplemonkey.c | PurpleMonkey's code; the rest of firmware/ is ChoralRoot's (Felucca's platform) |
tools/gen_pm_*.py, tools/emu/pm_*, tests/pm_*, tests/run_pm_tests.sh | its generators, emulator side and tests |
assets/purplemonkey/ | the approved concept art the sprites are cut from |
docs/ (other files), docs/upstream/, web/, firmware/src/cr_*.c | ChoralRoot's, kept as reference and as the baseline build |
Build and test
See BUILDING.md.
sh tests/run_pm_tests.sh # the engine's unit tests, then the emulator's acceptance scripts
./build.sh # the device image and package (needs Docker and the JieLi toolchain); installs nothing
Licence
GPL-3.0-only (LICENSE), as its sources: built on ChoralRoot FM-1, which is built on Felucca by Leo Kuroshita (Hügelton Instruments) with the FM6 engine of Melodee by Kerem Kilic; the drum synthesis is from SLOOP. LICENSING.md has the whole list. Independent of and unaffiliated with M-VAVE; M-VAVE and FM-1 are trademarks of their owners. Installing firmware is at your own risk.