docs · AISLING on the M-VAVE SMK-37 Elite

The Elite has the FM-1's chip and its audio path, so AISLING's whole app runs on it as it is: the same engine, the same eight pieces, the same pages and screen, saved the same way. What differs is the panel: 37 keys, more buttons, knobs that turn without end, pads, faders and wheels. One switch, AISLING_BOARD_SMK37, puts a board layer for the Elite under the FM-1's interfaces. Without it the same tree builds the FM-1's firmware exactly as before, to the byte.

It is for the SMK-37 Elite only, its layout read from M-VAVE's V016 firmware for it: not the SMK-37 Pro, and not the MKE-P37.

The site for the Elite is aisling.stephen8n.com/smk37, with the controls on a page of their own. The package is in the releases. Everything AISLING does is in the FM-1 version's manual.

1 What differs from the FM-1

2 The controls

Each of the Elite's buttons does the job of an FM-1 button. The manual, the cheat sheet and the screen use the FM-1's names; this is what they mean on the Elite:

Two buttons held together work as on the FM-1, by their Elite names: OCTAVE− with OCTAVE+ for five seconds, for instance, is the update mode. PARA has no light: the FM-1's EDIT has none either. The screen's hints still name the FM-1's buttons: TAP REC on the effects page means SEQ REC.

The site's controls page has what each one does.

3 Volume

The FM-1's MASTER is a pot, which stays where it was left. The Elite's K1 turns without end, so AISLING keeps the level itself. At each power-on it is half (−6 dB). One click of the knob moves it a step, and 43 clicks take it from silence to full. The steps follow the same curve as the FM-1's pot, so the quiet end has room. The level isn't saved.

4 The keys

The Elite's 37 keys run from C3 to C6. AISLING plays the middle 27, F3 to G5, which are the FM-1's 27: the white keys give the Lead, and the black keys do what the FM-1's do. The five below them (C3 to E3) and the five above (G♯5 to C6) are silent for now.

A key sounds near the bottom of its travel and stops when it is nearly back up. AISLING doesn't use velocity, as on the FM-1. The Elite's keys have no lights, so the FM-1's lit key for the note the Lead sounds has no place to show.

5 The pads and the faders

The 16 pads are PERFORM's sixteen effects, on any page, each on while its pad is down, and several together:

• Latch: hold > and hit a pad, and its effect stays on; the same again lets it go. > is lit while any is latched.
• Let go of everything: tap <. It also learns the pads' resting levels again, which frees one that has stuck.
• A throw: with a pad down, turn K5, K6, K7 or K8 for Filter, Wet, Energy or Duck. They go back to where they were when the last pad is up.

• Their lights: each pad glows in its group's colour, orange for the rhythm effects (Stutter to Roll), sea green for the echoes (Repeat to Reverse), heather for the space (Reverb to Wash) and yellow for the colour (Flange to Crush). A pad is bright while it is held and beats while it is latched. They are dark while the instrument sleeps.

The 4 faders are the mix, left to right: the Drone, the Sequence, Sequence 2 and the Lead. FADER BANK (lit) makes them the master actions instead: Filter, Wet, Energy and Duck. A fader does nothing until it is moved, so a piece's own mix holds, and the screen names what it sets. The Atmosphere is on no fader: it is on the MIX page. The mix is saved with the piece. Filter, Wet, Energy and Duck are not, on either bank or knob: they start in the middle each time the instrument is switched on.

Not used yet: the pitch and mod wheels and the pedal (read, with no job), KNOB BANK, the outer keys (C3 to E3 and G♯5 to C6), TRS MIDI out and Bluetooth.

6 The flash

The Elite's flash holds 1 MiB. Its regions are M-VAVE's own, read from M-VAVE's SMK-37 Elite V016 update package. AISLING writes three parts of it and never writes the rest:

The velocity calibration matters most: it was made for each Elite in the factory, and without a backup of that unit it can't be put back. AISLING's saved pieces sit over the start of the stock presets, so a full backup taken before the first install is what restores those: tools/fm1_rescue.py --write --presets BACKUP.bin (section 11).

The map is in firmware/hal/smk37/smk_flash_map.h. Its _Static_asserts keep every window the firmware writes off the protected ranges; at run time the flash driver refuses a write that would touch one; and tests/smk_flash_test.c checks the saved pieces, the update and the update loader against each range, byte by byte. The FM-1's own map would cross three of those ranges on an Elite, which is why the Elite has its own.

7 The pins

The Elite wires the same chip's pins to other things: PH8, the FM-1's TRS MIDI in, is a row of the Elite's button matrix, for instance, so the Elite has no MIDI in on its jack. The FM-1's drivers would set pins up wrongly here, so:

• The Elite build never touches PB1 (the charger's status line: held low for eight seconds, it resets the chip), PC7 (TRS MIDI out). PA8, PC9 and PA10, the pads', faders' and wheels' three analog lines, are inputs only.
• The pads' lights are sixteen colour LEDs on one data line, PC10, fed from the screen's SPI port switched to its other set of pins for the 0.8 ms a frame takes, between the screen's own transfers. That set's clock pin is PC9, the bottom row of pads' analog line; it stays an input, so the clock never reaches it.
• Every pin it does set up is in one table, firmware/hal/smk37/smk_pins.h. Each driver sets up its own rows from it, inputs first, and an output's level before its direction.
• The build fails if any of the FM-1's hardware headers (fm1_input.h, fm1_adc.h, fm1_lcd_hw.h, fm1_uart.h) is among the includes of any part of the Elite's firmware, by any path.

8 Building

The toolchain and the SDK are the FM-1's (BUILDING.md). Then:

./build.sh --board smk37                    # build/smk37/amb.fwsc
./build.sh --board smk37 --release 1.0      # build/smk37/aisling-smk37-elite-1.0.fwsc

The default board is the FM-1: ./build.sh makes the same bytes it always has, in build/. The Elite's build goes into build/smk37/ with the same file names (amb.bin, loader/ota.bin, the package), and its own checks: the app must fit the Elite's app area (0x4000–0x9CFFF), leave at least 2 KiB of RAM and 8 KiB of the pool spare, and pass the pin guard. A release's identity is SMK-37 Elite_353 and the version's three numbers, two digits each.

tools/mini_build.sh --board smk37 does the same on another Mac over ssh and fetches the package back.

After a change to shared code, build the FM-1 too and check that build/amb.bin, build/loader/ota.bin and its package are unchanged.

9 Testing

tests/run_tests.sh runs the Elite's tests with the FM-1's. Each control must fail:

10 The simulator

sh host/build_host.sh builds build/host/amb_host_smk37 beside the FM-1's amb_host. It runs the same scripts (the command list is at the top of host/amb_host.c), with the Elite's controls by their printed names, underscores for spaces:

• Buttons: FX, SCALE, CHORD, NOTE_REPEAT, PARA, GLOBE, PATCH, BT, ARP, SEQ, SEQ_PLAY, SEQ_REC, OCT- and OCT+, and KNOB_BANK (nothing yet), FADER_BANK, < and >.
• Pads and faders: pad N down, pad N up, tappad N (0 to 7 the top row, 8 to 15 the bottom); fader N V (0 to 3, V 0 to 1023).
• Knobs: K1 to K8. K1 is MASTER, turned like the others (turn, spin), so master N is refused.
• Keys: 0 to 36 (C3 to C6), or w0 to w21 for the white keys and b0 to b14 for the black.
• The battery: battery N sets its reading.

tests/smk37_scenario.py renames an FM-1 script for it:

sh host/build_host.sh
python3 tests/smk37_scenario.py tests/scenarios/pages.amb > build/pages_smk37.amb
build/host/amb_host_smk37 build/pages_smk37.amb build/pages_smk37

11 Installing, and going back

Done on one Elite with tools/fm1_install.py, in both directions; the web installer (web/fm1ota.js) uses the same protocol but has not yet been tried on an Elite.

First, a backup of the whole flash. It holds that unit's velocity calibration and its stock presets, and nothing else can bring those back:

python3 tools/fm1_install.py build/smk37/aisling-smk37-elite-1.3.1-dryloader.fwsc --uboot --port "SMK-37 Elite"
sudo python3 tools/fm1_rescue.py --location LOCATION "SMK-37 Elite_016.fwsc"

The first starts a loader that writes nothing and leaves the chip in its own update mode; the second, with no --write, reads the flash to a file. Switch the Elite off and on afterwards. Keep the file private: it is that unit's.

Installing: python3 tools/fm1_install.py aisling-smk37-elite-1.3.1.fwsc --port "SMK-37 Elite". On M-VAVE's firmware the Elite has three MIDI ports and the installer uses the one ending "-Private"; under AISLING it has one, "DUB-1 SMK-37 Elite". The installers refuse a package made for the other model.

Going back: the same command with M-VAVE's own SMK-37 Elite_016.fwsc. The Elite then runs V016 again, makes its sounds, and its controls work. Its first presets hold AISLING's saved pieces, though: a fader showed a stale value until it was moved. tools/fm1_rescue.py --write --presets BACKUP.bin puts the four preset sectors AISLING uses (0xC2000–0xC5FFF) back from the unit's own backup; it checks the flash chip's ID and that the backup's bootloader area and velocity calibration equal the flash's, and writes only the app area and those sectors. That route has not been needed yet, so it is untried on an Elite.

M-VAVE's own SMK37 OPEN firmware changes three sectors AISLING never writes (the Bluetooth record at 0xC0000, the end of the resources at 0xFD000, and 0xFE000). AISLING installed and ran over V016 afterwards all the same.

12 Settled on an Elite, and still open

Settled, on one Elite on V016 (November 2026):

• The matrix. The shift registers' bit order is the guide's. The rows read belong to the column after the one the guide gives, so fm1_input_tick files them there (smk_input.h); with the guide's column every button and knob read as its neighbour.
• The knobs turn the right way, all eight, and K1 is the volume.
• The buttons and their lights, each by its name. The keys: F3 to G5 sound.
• The pads and faders: the pads' order and effects, latch, < and a throw; the faders left to right, at rest 0 and at the top 1023.
• The stock loader's USB name, "ota-SMK-37 Elite_016": AISLING started it, and M-VAVE's package went back on.
• The flash chip's ID, 856014. EB6014 was read on an SMK-37 Pro; both are on the list, and any other part runs from RAM and saves nothing until it has been read and added.
• Saving, and running on the battery. A piece saved with BT held came back after a power-off, started from the battery with no cable; the icon showed three bars and Setup 76.
• The pads' lights: their order, their colours, bright while held, beating while latched.
• The protected ranges. After two installs and a return to stock, the bootloader area, the velocity calibration and the key at 0xFF000 equalled the backup taken before the first.
• A long run. An hour playing (13 November 2026, 18:39 to 19:40, read every five minutes over USB): no dropouts, no missed conversions in the analog scan; the heaviest audio block took 96% of its time.

Still open:

• The update record: whether the Elite's first-stage loader finds it at the top of the settings area (0xBFF00), so that a cable pulled mid-update resumes. No update has been interrupted on purpose.
• The battery's percentage: its span (BATT_PCT_LO) is a guess; it read 76 on a battery not known to be full or part used.
• The web installer on an Elite, and the presets' restore (section 11).

13 The files

14 Credits

AISLING is by CU_STE (www.stephen8n.com). Its board layer for the Elite follows M. Geisler's (genkigenki) SMK-37 ports on the smk37 branches of fm1-amb and fm1-fomni (GPL-3.0), written again for AISLING. The hardware's facts are from M. Geisler's guide, FM-1 to SMK-37 Pro (CC BY-NC 4.0), cited in each file and not copied. The flash regions were read from M-VAVE's own SMK-37 Elite V016 package, none of which is in this tree. LICENSING.md has the rest.

M-VAVE, FM-1 and SMK-37 are trademarks of their owners. AISLING is not affiliated with M-VAVE, or with the authors of the ports it follows.