Custom firmware that turns the M-VAVE FM-1 into a stand-alone MIDI processor: monitor, filter, remap, re-channelize and trigger MIDI without a computer.
- Help guide: how every page and control works, with screen captures.
- Flash the firmware: install it from desktop Chrome or Edge over USB. No software to install.
Latest version: 0.1.0 (build d120f8ed27c9d6b5, 2026-11-03 14:53 UTC)
- FM1-MidiProc.fwsc: the compiled firmware package, 459,316 bytes, for use with your own flasher.
- SHA-256:
4c119da121c813cd5f882390b9e1f3a474d92993207f3305d914090716c22834 - Update identity
FM-1_8000014, FM1 Open SDK family 7. Details in manifest.json.
GitHub builds the firmware from source on every change, with JieLi's 2.5.3 compiler. The build is byte-for-byte identical to the file above. Each run's firmware is available under Actions, and tagged versions are under Releases.
MIDI from TRS MIDI IN and USB passes through a pipeline and comes out of USB MIDI OUT:
- MIDI Monitor: a scrolling list of the last 100 messages. Colours show what the pipeline did: passed, blocked, remapped or triggered.
- Search with OP1–OP5 by port, channel, type and data ranges.
- Shortcuts turn the selected message into a rule or trigger.
- Filters: per port, pass or block each channel and each message type. Channel messages are set per channel.
- Remaps:
- Message rules change note, CC or program numbers and set the output channel.
- Channel rules move a port's channel to another channel.
- Rule Builder (GLO): build a remap rule by taking its input from one message and its output from another. Each can come from the monitor, the keys or the knobs.
- Event Triggers: an incoming message, or a range of values, sends a list of other messages, such as bank select and program changes for a whole rig.
- Knobs: KNOB 1–4 send a CC each, on the channel and CC number you choose, from any page.
- Live Keys: the FM-1's keys play notes with random velocity, and send program and bank changes.
- MIDI clock:
- One input owns the clock, so clocks are never merged.
- A metronome click plays on the headphone output, with its volume on MASTER.
- The Clock Monitor shows the source, run state, BPM and elapsed time.
- Patches: 16 named patches.
- Every setting can be dumped and loaded over SysEx, for backup and editing on a computer.
Measured on 2026-11-03 with version 0.1.0 (build a8c8fd4918ca4038), using tools/latency_test.py. The FM-1 was connected over USB to a Windows 11 PC. Notes were sent to the FM-1's USB input and timed on their way back from its USB output.
Inside the FM-1: from a message arriving to the processed message being handed to USB.
| Test | Messages | Mean | Max | Lost |
|---|---|---|---|---|
| Single notes | 2,000 | 0.13 ms | 0.47 ms | 0 |
| Bursts of 8 notes | 4,800 | 0.18 ms | 0.79 ms | 0 |
Every message took under 0.5 ms with single notes, and under 1 ms in bursts.
Round trip: PC → FM-1 → PC. This includes the PC's own USB MIDI handling in both directions, so most of the time is spent on the computer.
| Test | Probes | Min | Median | 95% | 99% | Max |
|---|---|---|---|---|---|---|
| Single notes | 1,000 | 0.28 ms | 0.50 ms | 1.01 ms | 1.84 ms | 3.66 ms |
| Bursts of 8 notes, whole burst | 300 | 1.02 ms | 1.91 ms | 3.33 ms | 4.02 ms | 6.25 ms |
To repeat the test, close other MIDI software and run python tools/latency_test.py. Add --burst 8 for bursts and --count to set the number of probes. Needs python-rtmidi.
The DoReMidi USB MIDI Host Box can be used to provide DIN MIDI in/out ports for the FM-1. With the USB Host Box, you have 2 inputs (1 DIN and 1 TRS) and 1 DIN output. The USB Host Box will also power the FM-1.
Note
MIDI from the host box's DIN input reaches the FM-1 over USB. So on the FM-1 it appears as the USB port (U in the monitor).
| Folder | Contents |
|---|---|
src/ |
Firmware, built on the FM1 Open SDK |
tools/ |
USB flasher (fm1_flash.py), patch SysEx tool, screen designer, site builder, tests |
design/ |
Screen designs, design decisions, patch and SysEx format |
html/ |
The help site and flash page, published with GitHub Pages |
To build the firmware, you need the JieLi PI32 toolchain. Run:
set FM1_PI32_TOOLCHAIN=C:\JL\pi32
python tools\fm1_flash.py --build
fm1_flash.py --build builds the firmware and flashes it to a connected FM-1.
FM-1 MIDI Processor is unofficial firmware. It isn't made or supported by M-VAVE. Use it at your own risk.