PollyStep BSPP
A clean-room operating system and software emulator for the BeatStep Pro, built in Rust with zero vendor code. The workflow you know from the stock firmware stays where your hands expect it; PollyStep adds chords of up to 8 notes on both sequencers, an arpeggiating CV output, Euclidean drum lanes, per-lane drum mutes, Fast Tie and high-resolution DAW control.
★ marks what is new beyond the stock BeatStep Pro.
Relative, Absolute or 14-bit Knobs
Press CONTROL and the panel becomes a MIDI controller while the sequencers keep playing. Knobs send relative CCs by default, and faster turns send bigger steps. Hold CONTROL + KNOBS for absolute CCs, or SHIFT + CONTROL for 14-bit high-res CCs on the DAW port, with values remembered per channel.
Mackie Control on Its Own Port
Two USB ports: BSPP MIDI carries everything, BSPP DAW carries Mackie Control and the high-res knobs. V-pots and faders follow the DAW. Pads and steps send notes and CCs on the User channel, with Scene Mode to store and recall scenes.
Tempo, Tap & Four Clock Sources
30–300 BPM with hundredths on SHIFT, three-tap tempo and a metronome. Clock from internal, USB, MIDI or the Clock In jack. SHIFT + PLAY restarts every track on the next Drum step; three quick presses of STOP send All Notes Off.
Play It From Outside
Notes on Seq 1 and Seq 2 channels play their CV/gate when stopped or muted, with pitch bend. Drum-channel notes play lanes and channel 3 transposes both sequences. DIN MIDI out mirrors the main port, clock first, and pads send polyphonic aftertouch in every mode.
Chords on Both Melodic Tracks
Seq 1 and Seq 2 can each hold a chord of up to 8 notes on every step. Build chords from the pads, record them live, and move them with the Pitch knob without losing the voicing.
Up to 8 Notes per Step
Hold a step and play several pads: the first sets the note, each further pad adds one. Or hold the pads first and press a step to drop the chord in, in the order pressed. Pads played together while recording land as a chord, and a dot on the display marks a chord step.
Arpeggiate Chords Over CV
Hold SHIFT + REC to set the arp rate (1/8, 1/16 or 1/32, plus triplets), order (up, down, up-down, as played or random) and range of 1–3 octaves. Settings are saved with the pattern.
Per-Output Octave Offset
Choose which chord note the CV plays for each pattern, and shift each output from −5 to +2 octaves (0: C3 = 5 V) to match your oscillators. The offset is stored as a device setting.
Scales, Transpose & Octaves
Chromatic, Major, Minor, Dorian, Mixolydian, Harmonic Minor, Blues and a User scale. Transpose live from the keyboard (0 to +12), shift sequences by octave, and send transpositions to both sequencers with TRNS LNK.
Faster Editing, Same Hands-On Flow
Patterns, chains, the touch strip, swing, randomness and probability all work the way the BeatStep Pro taught your hands. PollyStep adds faster ways to shape notes across many steps at once.
Every Step at Once
SHIFT + knob 1 offsets, and SHIFT + knob 2 sets, the velocity or gate of every step in the pattern. Touch any knob to see its value; gates run all the way to TIE and slide.
16 Patterns, Up to 64 Steps
Sixteen pattern slots per track, up to 64 steps each. Copy patterns between sequencers, build chains from the panel, and move all three tracks together with PRST LNK.
Looper & Roller
Touch 1/4 to 1/32 while playing to loop a slice of all tracks, then let go to rejoin the timeline. In Roller mode, or while recording, it repeats held pads at their current pressure and arpeggiates held keys.
Swing, Randomness, Probability
Set per project, or per pattern with CURRENT TRACK lit. REC records pads and incoming MIDI notes onto the nearest step, and long notes tie across steps.
Algorithmic Euclidean Percussion
Switch any drum lane to Euclidean with SHIFT + DRUM + pad, then spread its hits evenly from knobs 1–4, live, while hand-programmed lanes play alongside.
| New in 0.1 | Stock | BSPP |
|---|---|---|
| Chords per step | — | Up to 8 notes |
| CV arpeggiator | — | 5 orders, 1–3 octaves |
| Euclidean lanes | — | Per drum lane |
| Drum lane mutes | — | Per drum lane |
| Fast Tie & bulk edits | — | Two-step hold, SHIFT + knob |
| High-res knobs | — | 14-bit CCs on DAW port |
Request Early Access
Receive test builds of the cross-platform Rust emulator, early-access firmware packages (.led container), and development changelogs.
Every Control in 0.1
The complete control map for the current build. Open a group to see each control. ★ marks what is new beyond the stock BeatStep Pro.
Transport and tempo +−
| Control | Does |
|---|---|
| PLAY | Start, pause or resume; PLAY blinks while paused |
| SHIFT + PLAY | Restart all tracks at the next Drum step |
| STOP | Stop and rewind; press it three times quickly for All Notes Off on every channel |
| RATE/FINE knob | Tempo, 30–300 BPM; with SHIFT held, the hundredths |
| TAP | Three taps set the tempo |
| SHIFT + TAP | Metronome on/off (note 37 on channel 10) |
| SYNC (while stopped) | Clock source: INT → USB → MIDI → CLK (Clock In jack) |
Tracks and patterns +−
| Control | Does |
|---|---|
| SEQ1 / SEQ2 / DRUM | Select a track |
| < / > | Previous or next pattern; waits for the pattern to end while playing |
| Hold SEQ1/SEQ2/DRUM + step | Choose pattern 1–16 |
| SAVE + step | Save the pattern to that slot |
| SAVE + other sequencer + step | Copy a Seq pattern to the other Seq track |
| SHIFT + step 1 / step 2 | Clear the pattern / clear only its steps |
| LST STEP + step (with << / >>) | Set the last step, up to 64 steps |
| << / >> | Page through the step groups; both together toggle Sequence Follow |
| SHIFT + >> | Extend the pattern |
| PRST LNK | A pattern change moves all three tracks |
| SHIFT + hold SEQ/DRUM, release SHIFT, press steps | Make a pattern chain; it ends when you pick a pattern by hand |
Step editing +−
| Control | Does |
|---|---|
| Step button | Step on/off |
| KNOBS (Seq) | Knob mode: Pitch → Velo → Gate (gate up to TIE and slide) |
| KNOBS (Drum) | Knob mode: Shift → Velo → Gate |
| Knobs 1–16 | Edit that step; touching a knob shows its value |
| ★ Hold a step, press a later one, keep both held about 0.6 s | Fast Tie: one tied note across them |
| ★ SHIFT held | Tied steps show in cyan |
| ★ SHIFT + knob 1 / knob 2 | Offset / set the velocity or gate of every step |
| Hold a step + play a pad | Set that step's note and velocity |
★ Chords (Seq 1 and Seq 2) +−
| Control | Does |
|---|---|
| ★ Hold a step + play several pads | The first pad sets the note; each further pad adds one, up to 8 |
| ★ Hold several pads + press a step | The step gets their chord, in the order pressed |
| ★ Pads played together while recording | Recorded as a chord |
| ★ Pitch knob | Moves the whole chord; a dot on the display marks a chord |
MIDI plays the whole chord; the CV plays one note of it, or arpeggiates it.
★ CV and arpeggiator menu +−
| Knob | Sets | Saved |
|---|---|---|
| 1 | CV note: first entered, lowest, highest, or arpeggio | with the pattern |
| 2 | Arp rate: 1/8, 1/16, 1/32, plus triplets | with the pattern |
| 3 | Arp order: up, down, up-down, as played, random | with the pattern |
| 4 | Arp octaves, 1–3 | with the pattern |
| 5 | CV octave offset for this output, −5 to +2 (0: C3 = 5 V) | device setting |
Hold SHIFT + REC; works on the selected Seq. Everything in this menu is new beyond stock.
Scales and transposition (Seq) +−
| Control | Does |
|---|---|
| SHIFT + pads 9–16 | Scale: Chromatic, Major, Minor, Dorian, Mixolydian, Harmonic Minor, Blues, User |
| SHIFT + pads 1–3 / 4 / 5–8 | Direction (forward, reverse, alternate) / triplets / division 1/4–1/32 |
| Hold SEQ1/SEQ2 + keyboard pad | Transpose the sequence, 0 to +12 |
| Hold SEQ1/SEQ2 + OCT− / OCT+ | Move the sequence an octave; both together reset |
| TRNS LNK | A transposition goes to both sequencers |
| Pads 15 / 16 | Keyboard octave down / up, kept separately for each sequencer |
Drum +−
| Control | Does |
|---|---|
| Pad | Select that lane and play it; a lane's pad lights while its note sounds |
| Hold DRUM + pad | Select a lane silently |
| SHIFT + step 16 | Polyrhythm on/off; then LST STEP sets the lane's own length |
| ★ Hold DRUM + MUTE + pad | Mute or unmute that lane; Drum MUTE blinks while any lane is muted |
| ★ SHIFT + DRUM + pad | Euclidean on/off for that lane (Euc / oFF) |
| ★ Knobs 1–4 on a Euclidean lane | Steps (1–64), hits, rotation, hit velocity |
Mutes +−
| Control | Does |
|---|---|
| SEQ1 / SEQ2 / DRUM MUTE | Mutes on press; on a muted track, releasing unmutes; with drum lanes muted, a press unmutes them all |
Feel +−
| Control | Does |
|---|---|
| SWING / RANDOMNESS / PROBABILITY | Project values; with CURRENT TRACK lit, the pattern's own |
Recording +−
| Control | Does |
|---|---|
| REC (then PLAY) | Record pads and MIDI notes onto the nearest step; long notes tie across steps |
Touch strip +−
| Use | Does |
|---|---|
| Touch 1/4–1/32 while playing | Looper: repeats a slice of all tracks; letting go rejoins the timeline |
| Roller mode, or while recording | Repeats held pads at their current pressure; held keys are arpeggiated |
Projects and channels +−
| Control | Does |
|---|---|
| Hold PROJECT | Shows projects: current red, saved ones white |
| PROJECT + step | Load a project |
| SAVE + PROJECT + step | Save the project to that slot |
| CHAN + step | The selected track's MIDI send channel |
| SHIFT + CHAN + step | The selected track's receive channel |
Saved projects, channels and device settings survive power-off.
Control mode +−
| Control | Does |
|---|---|
| CONTROL | The panel becomes a MIDI controller while the sequencers keep playing |
| ★ Knobs | Relative CCs by default (binary offset; faster turns send bigger steps) |
| ★ Hold CONTROL + KNOBS | Switch to absolute CCs, values remembered per channel (AbS / rEL) |
| ★ SHIFT + CONTROL | High-res knobs: 14-bit CCs on the BSPP DAW port, values remembered per channel |
| KNOBS | Mackie Control on the DAW port (V-pots and faders); the faders follow the DAW |
| Pads / steps | Notes 36–51 / CCs 20–31 and 52–55 on the User channel |
| CHAN + step | User channel |
| SHIFT + step 9 / 14 / 15 / 16 | Roller on/off / Wait to Load Pattern / Global Tempo / Scene Mode |
| With Scene Mode on: step / SAVE + step | Recall / store a scene |
MIDI and USB +−
| Port / input | Does |
|---|---|
| USB: BSPP MIDI | Everything |
| USB: BSPP DAW | Mackie Control and the high-res knobs |
| DIN MIDI out | Mirrors the BSPP MIDI port, with clock sent first |
| MIDI in: Seq 1 / Seq 2 channels | Notes play their CV/gate when stopped or muted, with pitch bend |
| MIDI in: Drum channel | Notes play its lanes |
| MIDI in: channel 3 | Notes transpose both sequences |
| MIDI in: CC 123 | All Notes Off silences everything |
| Pads | Send polyphonic aftertouch in every mode |