TRIG pages (Digitakt mk1)

More TRIG sub-pages for the Digitakt mk1, OS 1.53, where each audio track picks a generator: a mod that changes what the track's steps play. TRIG pages is the framework; it has no generator of its own. The first one is TURING.

It is an elekloader mod, on core 4.0 and elekloader's seq-events: elekloader builds a custom OS file on your own machine, from your stock OS file and the mods you pick; nothing from Elektron is distributed.

Press TRIG again to step through them, as on SRC, FLTR and LFO; the title names the sub-page. With GEN OFF the page has two sub-pages, 1/2 and 2/2.

• 2/3 is drawn as the stock pages are: the stock knob rings, the labels in the stock font (a knob's value under it while it turns) and the header's pop-up with its long name and value ("Loop Lock=75%"). A generator may draw a knob's graphic of its own in the ring's place.
• Knobs A-H on 2/3 and 3/3 set the generator, never a trig; LEVEL is the stock's. The trig keys work as on 1/3.
• Each track's generator and knob values are kept on the +Drive (/cfw/trigp.a and /cfw/trigp.b, written in turn) and loaded at start-up. A generator is kept by its id, so a build without it finds the track OFF.
• The values are the track's, not the pattern's, and they do not lock.

How it works

• The sub-pages. A page view keeps the list of its sub-pages (page ids) as a vector at +0x7c (begin, end, capacity), the shown one at +0x90; pressing the page's key again steps through the list (% count), and the stock title names it "TRIG 2/3". The audio tracks' TRIG page is built with one id, 1 (SRC, FLTR and LFO with two). TRIG pages patches the page's draw (its vtable's slot 4, 0x40184018: 0x400368ba → tp_draw), which points the list at its own {1, 1, 1}, two or three long, and draws 2/3 and 3/3 itself. The stock code sees the TRIG page on each. A MIDI track's TRIG page (id 15) is left as it is.
• The knobs. While 2/3 or 3/3 shows, ev_enc takes A-H through the stock knob filter (a short list a notch at a time), as CUT's settings page does.
• The pop-up. ev_draw draws the inverted bar over the header, in the stock pop-up's font, while a knob turns.
• The step fire. seq-events' ev_gen_trig, ev_gen_notes, ev_fire_vel and ev_fire_locks (order 40) go to the track's generator.

The stock assets it draws with, found in the firmware and in an emulator's RAM:

Writing a generator

include/trigpages.h is the whole API. A generator adds one entry to the tp_gens table, a function that gives its descriptor: its id and name, up to seven knobs (name, long name, range, default, value text, an optional graphic), the step-fire callbacks, a UI tick, its view for 3/3 and GEN's graphic. It reads its values from tp_val[track].

"subscribe": [{ "event": "tp_gens", "fn": "turing_gen", "order": 50 }],
"cflags": ["-I../trig-pages/include"],
"requires": ["core", "seq-events", "trig-pages"]

Build

seq-events is in elekloader (mods/seq-events-dt1); build it the same way.

python -m elekloader.sdk.build . --stock Digitakt_OS1.53.syx            # -> out/trig-pages-0.1.elemod
python -m elekloader.lint out/trig-pages-0.1.elemod --stock Digitakt_OS1.53.syx \
    --with core-4.0.elemod --with seq-events-0.1.elemod

Status

0.1: built and linked by elekloader with core 4.0 and seq-events 0.1, alone, with TURING, and beside every mod of this set (digislicer, euclid, duck, GRAIN, WAVE, CUT). Not yet run. Things to check on the first run:

• TRIG pressed again: 2/2 (GEN OFF), the title, the GEN knob; with TURING 2/3 and 3/3, and back to 1/3;
• on 2/3 the rings, labels and graphics where the stock page has them; a knob's value under it and in the header while it turns;
• A-H never change a trig on 2/3 or 3/3; LEVEL still works; the trig keys do;
• another track: its own generator; a track without one on 3/3 goes to 2/2;
• the settings back after a restart.

Planned: open on 2/3 when the track has a generator; values per pattern (core 4.0 has the room); the trig keys' LEDs showing what the generator plays.

The stock OS file always recovers the unit: hold [FUNC] while powering on, press [TRIG 4] for OS UPGRADE, and send the stock .syx with Transfer.

Licence

GPL-2.0-or-later: LICENSE. Not affiliated with Elektron. Custom firmware is at your own risk.