DIRECT JUMP for Digitone

Direct Jump and Start on Bar for the Elektron Digitone mk1, as an elekloader mod (id directjump). Two settings decide what picking a pattern does while the sequencer plays:

• DIRECT JUMP: the pattern takes over on the next step, legato, carrying on from the same place in the bar.
• START ON BAR: the pattern starts from its first step on the next bar line, perfectly in time. Press the key of the pattern that's playing to relaunch it from its first step on the next beat, as an Erica Synths Perkons does.

Unticked, the Digitone behaves as stock.

By Robbie (designed and tested on a Digitone mk1, OS 1.44). There is no Digitakt version. GPL-2.0-or-later.

Unofficial and unsupported. Flashing modified firmware is at your own risk; the stock Digitone OS always recovers the unit (hold FUNC while powering on, TRIG 4 OS UPGRADE, send the stock .syx).

What you need

Install

Add elemods/directjump-1.5-os1.44.elemod in the elekloader app together with core-dn1, build, and send the firmware to the Digitone. From the command line:

python -m elekloader.patch --stock Digitone_and_Digitone_Keys_OS1.44.syx \
  --mod core-4.1.1-os1.44.elemod --mod elemods/directjump-1.5-os1.44.elemod --out Digitone_directjump.syx

It combines with DIGISNAKE for Digitone, PUMP for Digitone and the rest: checked linked and played on a unit with core-dn1 4.1.1, seq-events 0.1, DIGISNAKE 1.3, PUMP 2.10 and LØST LVLS 1.0 (earlier with DIGISNAKE 1.1 and PUMP 2.9). Tested on a unit: 1.0 never jumped (it took a pick's entry flag, 0xFF, for a stop); fixed in 1.1. 1.1 started the new pattern a step late, so the beat slipped a 16th at each jump; fixed in 1.2. 1.3 added RESTART PATTERN, which restarted on the next 16th and drifted off the beat; 1.4 replaced it with START ON BAR, whose relaunch waited for the bar line, where a 16-step pattern is at step 1 anyway; 1.5 relaunches on the beat.

Use core-dn1 4.1.1 whenever the build has two or more mod rows in SETTINGS (DIRECT JUMP and PUMP ANIMATION, say). With 4.1 and earlier, each mod row takes firmware heap at boot, and two of them can stall a first boot (the "FACTORY PROJECT >> +DRIVE" screen). 4.1.1 keeps the rows off the heap. It is in elekloader's source (mods/core-dn1), not yet a release: build it with the SDK (python -m elekloader.sdk.build mods/core-dn1 --stock ...).

Using it

SETTINGS > DIRECT JUMP and SETTINGS > START ON BAR: YES (or RIGHT) ticks a row, YES (or LEFT) unticks it.

Both on is the performance setup: jump between patterns without losing the groove, and relaunch the one playing on the beat. Tap it on every beat to stutter its first beat, or once a bar to keep replaying its first bar. A relaunch lands on a beat rather than a bar line because a 16-step pattern is on its first step at every bar line anyway: relaunched there, it could not be heard.

• Legato jumps: the new pattern plays on from the step the old one would have played, wrapped to its length. Playing step 38 of a 64-step pattern, a jump into a 16-step one goes on from its own step 7. In per-track scale mode every track lands where it would be had the new pattern been playing all along.
• The bar is the Digitone's own song position: the 16ths since PLAY, or the MIDI song position it is sent. So starts stay locked to the tempo and to other gear, whatever the patterns' lengths. A pick waits for the next bar line; picking again before then changes what starts. Into a pattern with another master speed, step 1 lands as close after the bar line as that speed allows (within a step).
• DIGISNAKE (1.1 or later): a start relaunches every snake from its path's start with the pattern, so the whole groove restarts together. A legato jump leaves the snakes walking.
• Chains play on as stock. Song mode is left as stock.

The settings are saved with the project, and on OS 1.44 they survive a power cycle. Loading a project saved without them, or making a new one, keeps whatever the unit had.

How it works

The Digitone's sequencer changes pattern in its 24 PPQN tick interrupt. Two ticks into every master step it looks at the next entry of its pattern source (the chain), and only on the master length's last step it arms the change; at the next step boundary it switches, starting the new pattern at step 0.

Picking a pattern gives the source a new chain and sets its index to -1 until the switch. DIRECT JUMP reads that (site 0x40095fdc) and arms the change itself, as the stock does:

• a jump on the very next step, with the step after the one playing as the start step;
• a start with step 0 as the start, but only on the step that puts the new step 1 on a bar line (a relaunch: a beat) of the song position (16ths × 6 + ticks; a new pattern's first step is heard one of its steps after the switch). Until then it holds the stock arm off too.

The switch's per-track arithmetic assumes step 0 (it reads the old pattern's track speeds and never wraps), so after a jump DIRECT JUMP works each track's step out again from the new pattern (site 0x4009643a). It counts each start in dj_starts, which DIGISNAKE 1.1 and later read (a weak import) to relaunch its paths.

The SETTINGS rows are core-dn1 ev_settings rows; the settings are core-dn1 project data (DJMP), and on 1.44 a change asks the OS to refresh its power-up copy of the project, as DIGISNAKE and PUMP do.

Checked

• Builds, lints and links with core-dn1 4.1.1, seq-events 0.1, DIGISNAKE 1.0, PUMP 2.9 and LØST LVLS 1.0; elekloader verified the patched image (every other section byte for byte, the main OS unpacks in place).
• The compiled ColdFire code read back against the stock routines it stands in for.
• The logic run natively against a model of the sequencer's state: every condition that leaves a change to the stock, the arm's fields, the start step, and each track's step and offset in per-track mode at mixed speeds and lengths; and a tick-by-tick timeline of 14,112 picks at step lengths 3-48: every start's first step lands on a bar line (at equal speeds exactly), within a bar of the pick; and 2,016 relaunches, each on a beat, within a beat of the press.
• On a unit (Robbie's Digitone mk1, OS 1.44, with DIGISNAKE 1.1, PUMP 2.9 and LØST LVLS): DIRECT JUMP's legato jumps, START ON BAR's starts on the bar and 1.5's relaunches on the beat all stay in time, and the snakes relaunch with the pattern.

Building

With elekloader and an m68k cross GCC on the path:

python -m elekloader.sdk.build --stock Digitone_and_Digitone_Keys_OS1.44.syx .

Credits and third-party code

DIRECT JUMP is Robbie's own work, written with Claude (Anthropic). The SETTINGS rows' callbacks are adapted from digihealth's SYSTEM INFO row (irpina/digihealth, sysinfo.s, GPL-2.0-or-later), as PUMP's are; the power-up copy request follows DIGISNAKE's. It builds against irpina's elekloader SDK and runs on core-dn1 (GPL-2.0-or-later); none of them is included here. The firmware addresses were found by studying the Digitone's own OS so the mod can work with it; no Elektron code is included.

Trademarks

Elektron and Digitone are trademarks of Elektron Music Machines. They are named only to say what this works with. This project is not affiliated with or endorsed by Elektron.

Licence

GPL-2.0-or-later, see LICENSE.