Manual

LCD-4 turns the M-VAVE FM-1 into a four-track pocket groovebox: a drum machine with four kits and three synth tracks with sixteen sounds, each modelled on a classic's circuit. You write 16-step patterns, chain them, give the synths chords to follow, and play punch-in effects over the top. On the screen, every sound has its own little LCD game, in the manner of the old handheld games and the pocket synths that took after them, and it moves with the music.

1Install

Try it first: the browser emulator runs the same code with sound, played with the mouse, a touch screen or the keyboard.

Install from the browser: open the web installer in Chrome or Edge, connect the FM-1 with a USB data cable and press Install. Don't unplug it while it's writing; when it finishes, the FM-1 restarts into LCD-4.

Install from the command line: download lcd4-X.Y.Z.fwsc from the latest release, install Python 3 with pip3 install mido python-rtmidi, and from the LCD-4 source run:

python3 tools/fm1_install.py lcd4-X.Y.Z.fwsc

Which version: the Setup page (GLO) shows it at the bottom left, and the start screen under the name.

Go back: "Back to the stock firmware", at the bottom of the installer page, puts M-VAVE's firmware back (download the FM-1 V15 file from the link there, choose it, press the button). M-VAVE's own updater, M-UPGRADE, works too.

Coming from IND-1 or AMB-1: LCD-4 keeps its settings where they kept theirs, under another name, and its patterns in a place of their own. None of them reads the others': installing LCD-4 starts it with the first demo song, and LCD-4's first save replaces what the other firmware had saved.

2Getting started

1. Switch the FM-1 on and turn MASTER up. LCD-4 starts with a demo song in its patterns, stopped.
2. Press PLAY. Four tracks play: an 808, a 303-style bass, Juno chords and a chip lead, over a chain of patterns and a chain of chords.
3. Turn ALGORITHM to pick a track. The tabs under the screen show the four tracks and what each plays; the scene on the screen changes with the track's sound.
4. Turn PRESETS to give the track another sound (on track 1, another kit). Try them all: each has a scene of its own.
5. On a synth track, play the keys. OCT− and OCT+ move them an octave.
6. Turn ALGORITHM to track 1, the drums. A black key picks a part (and plays it); the white keys are that part's 16 steps: press one to switch it on or off.
7. Press REC (writing) while it plays, and play: on a synth track, the notes go into the pattern; on the drums, the black keys do. Press REC again to stop writing.
8. Press HOME for the patterns: a white key picks the next pattern. Hold one key and press others for a chain.
9. Hold FX and press a white key: an effect, for as long as you hold it.
10. Hold any button for a second and a card says what it does. Your work saves itself a few seconds after you stop; SAVE saves at once.

3Controls

A page's button pressed again goes back to the Sound page. Hold OCT− and OCT+ together for five seconds for the update mode (see Troubleshooting).

4The screen

The top of the screen is an LCD, as on a handheld game:

• The status line: the pattern playing (P01), its place in the chain (1/4), the chord (on a dark tag); then REC, play or stop, and the tempo in segments. A small dot means changes not saved yet. A message takes the middle for a moment when you change something.
• The scene: a little game for the track's sound. Its parts are LCD segments: dark when lit, and faintly there when not, so you can see every pose a character can take. The music lights them.
• The steps: the track's 16 steps. A filled cell has a note (on the drums, the part plays); a tall one is accented; lines across it are a ratchet; a tail joins a slide to the next step; a dot above is a locked knob, a mark at its top-left an effect written there. The bar under it is the playhead. Small dots under the drums' steps show where the other parts play. Steps past the pattern's length are dashes.

Below the LCD:

• The tracks: four tabs, the selected one lit in its colour, with each track's sound and a meter. A muted track is struck through.
• The knobs: the page's name and its place among the pages (the dots), the four knobs' names, rings and values. A knob just turned is lit. On the drums, the part the knobs are for is at the left.

5The tracks

Track 1 is the drums; tracks 2, 3 and 4 are synths. Any synth track can load any of the sixteen sounds; the drum track loads any of the four kits. Each track remembers its knobs for every sound, so you can try another sound and come back. Each track has a colour: orange, cyan, yellow and pink.

The Track page (ENV) sets the track's Level, Pan, and how much it sends to the Delay and the Reverb. The Mixer (SEL) has the four levels together, and mutes.

6The drums

The black keys pick the part (and play it). The white keys are the part's 16 steps: press a step and let go to switch it on or off. The Sound page's knobs are the part's own: Tune (an octave up or down), Decay (a quarter to four times as long), Tone (what it means depends on the part: the kick's click, the snare's snap, the hats' brightness) and Level.

• ENV + a white key: an accent on that step (all the drums on it play harder).
• EDIT + a white key: the step cleared (every part on it); EDIT + a black key: the part's whole row cleared.
• OCT− / OCT+: the part before, the next part.
• Hold a step and turn KNOB 1 or 2: that step's tune or decay, moved for every part on it.

Every kit has the same eleven places, so a pattern written on one kit makes sense on another:

The closed hat cuts the open hat off, as on the machines.

• 808: a sine that rings and dies for the kick and toms (its bridged-T resonators), two heads and snappy noise for the snare, a clap of noise bursts, the cymbal and hats from six square oscillators through band-passes (the 808's own frequencies), the cowbell's two squares.
• 909: a kick swept down from a click, triangles and noise for the snare, swept toms, hats and cymbals of metal and noise (the real ones were 6-bit samples).
• Arcade: a games console's sound chip: pulse and triangle waves swept in pitch, its 15-bit noise register (long, or short and metallic), volume in sixteen steps; a blip, a laser zap and a coin.
• Box: a CR-78 and a TR-606: a soft kick, a snare, toms, a conga, claves, a guiro's scrape, metallic hats, a tambourine and a cowbell.

On screen, Pip plays the 808, a press shop stamps to the 909, invaders march to the arcade kit and Pip plays the congas on a beach to the box.

7The synth sounds

Each sound has four knobs on the Sound page (LFO). A and B (the first two) can be locked on a step. Mono sounds glide where notes overlap; the keys (Poly to Bells) play four notes at once.

Some of them, closer:

• Acid: a saw through a resonant low-pass with the 303's high-pass in its feedback, its envelope short or long (Decay), and its accent: louder, a shorter, brighter sweep, and the "wow" that builds when accents follow each other. A slide (see Writing) glides into the next note without starting the envelopes again.
• Poly: the Juno's one oscillator (a saw and a pulse whose width moves), its 24 dB filter moved by the same envelope as the amp, and its BBD chorus: Chorus off, I, II, or both.
• Strings: a divide-down saw and its octave, mellowed, through the Solina's ensemble: three delays wobbling at two rates, 120 degrees apart.
• E.Piano: two FM pairs, as the DX7's: the body (Bark, dying over a second) and the tine (ratio 14, gone in 50 ms); Tremolo is a suitcase's stereo pan.
• Arcade: Wave picks the console's channel: a pulse of 12.5, 25 or 50 %, the 32-step triangle, or noise (its pitch the note). Effect is what a tracker would do to it: vibrato, portamento, an arpeggio (the chord's), a blip (down from an octave), a rise. Decay at its top holds the note. Crunch is a slower, coarser converter.
• Arp: each note of a step runs as an arpeggio for as long as the step lasts. A chord on the step runs over its notes; a single note runs over the chord playing (see Chords), or its triad. Mode: up, melodic (leapfrogging), down, octaves. Rate: sixteenths, triplets, 32nds, 48ths.

8Writing

On the steps (any time, playing or not): on the drums, the white keys always are the part's steps. On a synth track, the Steps page (SEQ) turns the white keys into its 16 steps.

• Press an empty step: it takes the notes in hand, what you last played on the keys (a chord, if you played one), one step long. Stopped, you hear it.
• Press a full step: it's cleared.
• Hold a step and turn the knobs: KNOB 1 its note (a chord moves together), KNOB 2 its length (in quarter steps, up to 16 steps: a long note holds over the next steps), KNOB 3 and 4 the sound's A and B for that step alone (a lock). Turning a held empty step fills it first.
• Hold a step and press OCT−: a slide into the next note (the 303's: on a mono sound the pitch glides and the envelopes go on). OCT+: a ratchet, the note played two, three or four times in its step.
• ENV + a step: an accent. EDIT + a step: cleared.

Live (REC on, playing): what you play goes into the pattern playing, on the nearest step.

• Synth tracks: each key's note and how long you hold it; keys pressed together make a chord on one step; a key pressed while another is still held makes the first slide into it. Hold ENV for accents.
• The drums: the black keys, on their steps (hold ENV for accents). A hit just before a step doesn't play twice.
• On a synth track, turning KNOB 1 or 2 on the Sound page writes their values as locks on the steps as they pass.
• An effect held (FX) is written onto the steps it plays over.

Step by step (REC on, stopped, a synth track on the Sound page): each key (or chord) goes on the next step, from the first; EDIT is a rest. The cell waiting for a note blinks.

Clearing: EDIT + REC clears the selected track in this pattern.

9Patterns and chains

A pattern holds all four tracks: the drums' steps and accents, the three synth tracks' steps, the effects written on its steps, and its length. There are sixteen, on the white keys of the Patterns page (HOME), or with HOME held from any page.

• A key: that pattern next. While playing, it starts when this one ends; stopped, at once. The pattern playing is the one you edit.
• Hold a key and press others, or hold HOME and press keys in order: a chain, up to 64 long, repeats allowed (1, 1, 1, 4 plays pattern 1 three times, then 4). It starts over when this pattern ends.
• SAVE + a key: this pattern copied there. EDIT + a key: that pattern cleared.
• The keys' lights show the chain; the one playing blinks.

The page's knobs: Tempo (40–240), Swing (50 % straight to 75 %, the off-beats later), Length (this pattern's steps, 1–16) and Key (everything the synths play, moved to it; see Chords).

10Chords

The Chords page (ARP) puts sixteen chords on the white keys, in C (Key moves them):

• A key: that chord, held. Hold a key and press others, or hold ARP and press keys: a chain of up to 64, a chord each time a pattern starts (so a four-chord chain over a one-pattern loop goes round every four bars). EDIT + a key: no chords.
• Follow (KNOB 1, for the selected track): the track's notes follow the chord. Write the parts in C; each note moves with the chord's root (no more than half an octave), and the scale bends to the chord: in a minor chord E is played as Eb, A as Ab and B as Bb; a seventh chord flattens B; a suspended chord raises E to F. A bass line, a riff and a pad written once then play the whole progression.
• The Arp sound plays the chord's notes; the Arcade's arpeggio takes its major or minor.

With no chords, the notes play as written (and Key still moves them).

11Effects

Hold FX and press a white key (or use the keys on the FX page): the effect lasts as long as you hold the key. While writing, it's written onto the steps it plays over, and plays there every time. EDIT + an effect's key takes it off the pattern's steps.

The FX page's knobs: Time (the delay's, in sixteenths: 1/16, 1/8, 3/16, 1/4, 3/8), Feedback, Space (how long the plate rings) and Punch (a bus compressor: more of it, louder and tighter).

12The pages

Setup:

• Tune: ±50 cents.
• MIDI out: off or on (see MIDI).
• Clock: Auto follows MIDI clock when it comes; Internal ignores it.
• Demo: pick one of four demo songs (Pocket, Arcade, House, Lo-fi), then hold SAVE for a moment to load it. It replaces every pattern and setting, and is saved like any change (by itself a few seconds after, while stopped): save anything you want to keep before you load one.
• The status line shows how much of the FM-1's time the sound takes (CPU).

13MIDI

MIDI comes in over USB and the TRS jack, and goes out over USB.

• In, notes: channel 1 (or 10) plays the drums (General MIDI: kick 36, snare 38, toms 41, 45 and 48, rim 37, clap 39, closed hat 42, open hat 46, cymbal 49, cowbell 56); channels 2, 3 and 4 play tracks 2, 3 and 4. While writing and playing, they're written like the keys.
• In, clock (Clock: Auto): the steps follow MIDI clock, start and stop start and stop LCD-4 (start: from the chain's top). The status line shows EXT for the tempo.
• Out (MIDI out on): the drums on channel 10 (the notes above), tracks 2–4 on channels 2–4 with their lengths; and clock with start and stop when LCD-4 runs on its own tempo.

14Saving

LCD-4 keeps everything in the FM-1's memory: the sixteen patterns, the chains, the chords, every track's sound and knobs (for every sound), the kits' parts, and the setup.

• By itself: a few seconds after a change, but only while stopped. Writing to the memory interrupts the sound for a moment, so it never happens while it plays. A dot in the status line means there are unsaved changes.
• SAVE: saves now, playing or not.

15Troubleshooting

Update mode: hold OCT− and OCT+ together for five seconds. A countdown appears; let go before it ends to cancel.

Calibration: if a button or knob does the wrong thing, hold OCT− and OCT+ while you switch the FM-1 on. The screen then asks you to press each button and turn each knob in turn.

Clicks or dropouts: the most the FM-1 has to do is three tracks of four-note chords with every drum on every step; even then it keeps up, measured on the FM-1, with a margin. If it ever runs short, LCD-4 plays fewer notes at once on the keys (three, then two) until it has time again. The Setup page shows the load.

After a crash: LCD-4 shows a red CRASH screen and restarts by itself a few seconds later. The next start shows RESTARTED AFTER A CRASH and an address (PC ...) for a moment. If you report the problem, include that address and what you were doing.

Safe mode: if LCD-4 crashes twice in a row while starting, it starts in SAFE MODE instead. There's no sound, but USB works, so the web installer can reach it: reinstall LCD-4, or put the stock firmware back from the same page. Press PLAY to try starting LCD-4 normally again. If even safe mode fails twice, the FM-1 drops into the chip's own update mode, and only the rescue below can reach it.

Recovering an FM-1 that won't start

An FM-1 in the chip's own update mode shows a blank screen, and neither the web installer nor M-VAVE's updater can see it. A script in the LCD-4 source puts M-VAVE's firmware back, on a Mac, with the USB cable you already have. In Terminal, from the LCD-4 folder:

bash tools/fm1_rescue.sh

1. If a window asks to install the command line developer tools, click Install. When it has finished, run the line again.
2. If it asks for a password, type your Mac password (nothing shows as you type) and press Return.
3. When it says it's waiting, plug the FM-1 in and switch it on. The script catches it, checks the chip, saves a backup of the FM-1's memory in the fm1-rescue folder in your home folder, and asks before it writes anything.
4. Type yes and press Return. Don't unplug anything until it says it's restarting the FM-1. The FM-1 then starts into its original firmware, and you can install LCD-4 again from there.

The script downloads M-VAVE's FM-1 V15 firmware and JieLi's flash loader, and checks both against known fingerprints. It writes only the firmware area of the memory, never the bootloader or the FM-1's own settings, and checks everything it writes. Running it again is always safe. If the FM-1 never shows up at all, Felucca's FM-1-transporter (a small RP2040 board wired to the USB lines) can still reach it.

16Credits

LCD-4 is free software under the GNU General Public License, version 3. If you share the firmware, you must also share its source code.

• The idea follows the little synths that live in a calculator's body, Teenage Engineering's pocket operators, and the handheld LCD games their screens took after. LCD-4's sounds, patterns, scenes and characters are its own.
• The sounds are modelled on the circuits of the Roland TB-303, SH-101, Juno-60, TR-808, TR-909, CR-78 and TR-606, the Minimoog Model D, the Yamaha DX7, the Sequential Prophet-5, the Oberheim OB-Xa, the ARP Solina, the Korg MS-20 and M1, the PPG Wave, and the sound chips of the NES and the Game Boy.
• LCD-4 is built on IND-1, itself built on AMB-1 by Charles Vestal: the engine's frame, the screen and knob code, the simulator and the browser emulator.
• The reverb is Jon Dattorro's plate ("Effect Design, Part 1", JAES 1997), by way of FoMni-1, AMB-1 and IND-1. The ladder filter is solved as in Vadim Zavalishin's "The Art of VA Filter Design".
• The platform (hardware layer, USB, update loader, installer and storage) is from Felucca by Leo Kuroshita, Hügelton Instruments, by way of X0X, AMB-1 and IND-1. X0X's drum machines showed how the black keys pick the parts.
• The idea of running FM-1 firmware in the browser comes from Groove OS.
• The fonts are Barlow Semi Condensed and Terminus (SIL Open Font License).

M-VAVE and FM-1 are trademarks of their owners, as are the names of the instruments above. LCD-4 is not connected with M-VAVE, Teenage Engineering, Nintendo, Roland, Yamaha, Korg, Moog, Sequential, Oberheim, ARP, PPG or Hügelton Instruments.