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FirmwareM-VAVE FM-1

ACID FM1

kclack/acid-fm1 · ★ 0

Acid bassline instrument: monophonic saw/pulse voice, slide, accents, ratchets and probability on up to 64 steps, with two browser emulators.

README from GitHub, AGPL-3.0

ACID FM1

An original acid bassline firmware for the M-VAVE FM-1, with two browser emulators. Inspired by the public feature set of Arturia Acid V and classic acid instruments. No Arturia code, presets, or assets are used.

Experimental, version 0.1.0. Builds and simulations are tested; this firmware has not been run on a physical FM1. Do not interpret a successful compile or browser demo as proof of device timing, audio quality, or safe recovery.

What is implemented

  • Monophonic saw/pulse voice with PolyBLEP edges and 2× voice oversampling.
  • Original saturated four-pole TPT feedback filter; cutoff, resonance, envelope, decay, accent amount/attack, tracking, bass boost, clipping.
  • Legato slide, variable pulse width, sine sub, circuit noise, vibrato, tune.
  • Up to 64 steps with notes, rests, accents, slides, per-step probability, 1–4 ratchets, and cutoff locks.
  • Independent note/accent/slide loop lengths, swing, four sequence directions, root/scale selection, seeded generation, and mutation.
  • Three tempo-related modulators with independent cycle lengths; six shapes including eight-point curves, and cutoff/resonance/PW/drive/pitch/level routes.
  • Seven distortion modes, mono feedback delay with stereo taps, chorus, and compact four-comb ambience. Not Arturia's complete effects suite.
  • Live last-note-priority mode and an arpeggiator; MIDI notes, transport, 24-PPQN clock and CC control. MIDI-clock silence timeout.
  • Eight original factory patches; four hardware project slots with A/B-sector CRC-protected storage supplied by the platform.
  • Browser patch save/import/export, MIDI input, two-cycle WAV bounce, one-cycle MIDI export, keyboard, scope, and generation undo.
  • USB MIDI, TRS MIDI input, USB audio, screen mirroring, and update support supplied by fm1-base / felucca-bsp. Bluetooth and Wi-Fi are deliberately left out of this first build. There is no network reporting in the application.

What it is not

This is an independent instrument, not Acid V running on the FM1 and not a circuit-accurate or sonically validated clone. Arturia's proprietary circuit model, full 14-mode distortion / 17-effect collection, preset library, drag-and- drop DAW integration and other desktop features are not reproduced. The attached Windows installer could not be transferred into this environment because the upload download tool has a 32 MiB limit; it was not run or extracted. Public documentation was used instead. See the feature matrix.

The studio and hardware emulator share the same C sound engine. The hardware emulator additionally runs the actual application, panel mapping and LCD code against a simulated platform. It does not emulate the processor, physical codec, flash electrical behavior, USB timing, or CPU load. Browser local slots and hardware slots are separate; there is currently no studio-to-device patch transfer protocol. The hardware-view emulator edits its own simulated device.

Build here or on Linux x86-64

git clone --recurse-submodules https://github.com/kclack/acid-fm1
cd acid-fm1
python3 -m pip install pillow fonttools
sh tools/test.sh

The native test compiles with cc, then the complete app compiles against the platform's host simulator. The device is JieLi AC79 / pi32v2, not ARM.

# All downloads stay in the directory you select.
sh base/tools/get_toolchain.sh "$PWD/.toolchains/jieli"
python3 tools/fetch_sdk.py "$PWD/.toolchains/ac79-sdk"
export JIELI_TOOLCHAIN="$PWD/.toolchains/jieli/toolchain"
export AC79_SDK="$PWD/.toolchains/ac79-sdk"
python3 base/tools/build.py . --release 0.1.0

Outputs: build/acid-fm1.bin, build/loader/ota.bin, and build/acid-fm1-0.1.0.fwsc. The three SDK packaging files are hash-checked. The build checks RAM/flash limits, RAM-only routines, unintended MMIO, target 64-bit-multiply hazards, and absence of soft-double routines.

Browser builds

Activate Emscripten 4.0.20, then:

sh tools/build_web.sh
python3 -m http.server 8000 --directory web
# http://localhost:8000/

web/engine.wasm is compiled from dsp/acid.c with the studio bridge. web/hardware/app.wasm is the complete app built with fm1-base's simulator. Both use -ffp-contract=off. No npm install is needed to play the site. GitHub Pages serves the checked-in web/ artifacts through .github/workflows/pages.yml.

Installation and recovery

First back up the projects and patches of whichever firmware is on your FM1. The four slot pairs and settings area used by this application can replace existing firmware's data. Do not install on an FM1 you cannot recover.

Use the download in the experimental release with the fm1-base CLI:

python3 -m pip install mido python-rtmidi
python3 base/tools/fm1_install.py build/acid-fm1-0.1.0.fwsc

Check --help and the base's documentation before updating. The package embeds the base update loader; this project does not flash a device automatically, bundle stock firmware, or install an alternative bootloader. If the existing firmware does not support that update path, use its documented update method. Recovery references: FM-1-transporter and the official Workbench.

Hardware acceptance checklist: docs/HARDWARE_TEST.md.

Contributing and license

Original code: AGPL-3.0-only. Platform: MPL-2.0 file-by-file; fonts: SIL OFL; three SDK package files: Apache-2.0. See THIRD_PARTY.md. The full-source release includes both pinned submodules. Bugs and contributions are welcome; no support or performance guarantee is implied.