OpenElixir-02 v1.0

First stable release of OpenElixir-02, custom firmware for the Erica Synths LXR-02 drum machine.

OpenElixir-02 extends what the LXR-02 already does while staying fully backwards compatible: kits,
patterns and projects from the stock firmware load and play as before, the MIDI implementation is
unchanged, and the update works with the stock bootloader. Every change to the core sound comes with
a switch in the config menu, so the stock sound is always one setting away.

Tested on hardware by the author. OpenElixir-02 is not official Erica Synths firmware and is not
affiliated with or approved by Erica Synths. Install it at your own risk.

Kit management

Load full kits and single voices from any project:

• Single voices: hold LOAD and press step button 1-7 (Drum 1 ... OP HH). Choose the kit with the
  encoder, also from other projects, and press the encoder button to load just that voice into the
  current kit. The menu stays open, so you can try several kits.
• Full kits: "Change Project" below kit 0 in the load and save kit menus loads kits from other
  projects and saves kits into them.

Freely assignable voice engines

Each of the 6 voice slots can run any engine: drum, snare, cymbal or hi-hat. Select a voice and press
SHIFT + KIT (or send NRPN 98). The engines are saved in the kit; kits from the stock firmware load
with the stock engines.

Details for kit management and engines:
docs/ENGINES.md.

Limiter

Voices and FX are summed in 32 bit, followed by a limiter on each output, so loud kits no longer
hard-clip. Levels that didn't clip before are unchanged. Config menu "lim" (2nd page) switches it off
for exactly the stock mix.

Under the hood

• About 10 % less CPU load.
• Many stock firmware bugs fixed (MIDI, sequencer, SD card, memory corruption), most of them found in
  the firmware review by jhw in
  erica-synths/lxr-desktop-app#3.
• A project save that can't lose the saved project: it is written into a new folder and replaces the
  old one only when everything was written. The card needs free space for a second copy of the
  project (a few hundred KB).

Stock issues that are kept on purpose:
docs/KNOWN_ISSUES.md.

Installing

1. Download LXR_OpenElixir-02_V1.0.img below.
2. Copy it to the top folder of the SD card and delete any other LXR*.img files there.
3. Switch the LXR-02 off, insert the card, hold the encoder button and switch it on. Keep holding
   until "LXR Updater" appears.
4. Wait for "Update OK!". The device restarts with the new firmware.

To go back, install the official firmware update from Erica Synths the same way. Kits saved with
OpenElixir-02 keep working there; slots with a different engine play with their stock engine.

The .hex and .elf files are for programming and debugging with an ST-Link; you don't need them for
a normal update.

OpenElixir-02 v0.2

Second release of OpenElixir-02, custom firmware for the Erica Synths LXR-02 drum machine.

Pre-release. Tested on hardware by the author. OpenElixir-02 is not official Erica Synths
firmware and is not affiliated with or approved by Erica Synths. Install it at your own risk.

New: assignable voice engines

Each of the 6 voice slots can now run any of the 4 engines: drum, snare, cymbal or hi-hat. Want three
snares, or a second kick instead of the cymbal? Select the voice and press SHIFT + KIT: turn the
encoder to choose the engine and press the encoder button to apply it. Via MIDI, NRPN 98 does the same.

• Track 7 is always the second trigger of slot 6, for any engine: track 6 plays with decay A (d1),
  track 7 with decay B (d2), and they cut each other off like closed and open hi-hat.
• A switched slot starts from the new engine's default sound. Its menu pages, value ranges and
  modulation target names follow the engine.
• The engines are saved in kits, projects and the autosave.
• Fully compatible: kits from the stock firmware, older versions or anyone else load with the
  stock engines and sound exactly as before. The stock firmware still loads OpenElixir-02 kits
  (switched slots then play with their stock engine). All MIDI CC and NRPN numbers are unchanged.

Details, including the MIDI table: docs/ENGINES.md.

Other changes since 0.1

• About 10 % less CPU load in the worst case (all voices busy, heavy FX), with identical sound.
• Fix: switching the FX delay to ping-pong could overwrite up to 32 KB of other sound data. (Also in
  the stock firmware.)
• Fix: saving a project into an existing project slot renamed kit 1 to ".SNG". (Also in the stock
  firmware.) If one of your kits got that name, rename it once.

Everything from 0.1 is included: no more hard clipping in the mix (32-bit mix bus with a limiter on
each output).

Installing

1. Download LXR_OpenElixir-02_V0.2.img below.
2. Copy it to the top folder of the SD card and delete any other LXR*.img files there.
3. Switch the LXR-02 off, insert the card, hold the encoder button and switch it on. Keep holding
   until "LXR Updater" appears.
4. Wait for "Update OK!". The device restarts with the new firmware.

To go back, install the official firmware update from Erica Synths the same way. Kits saved with
OpenElixir-02 keep working there; slots with a different engine play with their stock engine.

The .hex and .elf files are for programming and debugging with an ST-Link; you don't need them for
a normal update.

OpenElixir-02 v0.1

First release of OpenElixir-02, custom firmware for the Erica Synths LXR-02 drum machine.

Changes from the stock firmware (1.7)

• No more hard clipping in the mix. Voices and FX are summed in 32 bit, followed by a limiter on
  each output. Kits that didn't clip before sound exactly the same; louder ones are limited instead
  of clipped. Voice drive/distortion and the FX are unchanged.
• Renamed to OpenElixir-02. The start-up screen shows "OpenElixir-02 / Version 0.1" and the
  device appears as "OpenElixir-02" (manufacturer "tunefish.at") on USB. MIDI mappings in your DAW
  that use the old "Sonic Potions USB MIDI" port name need to be set up again.
• Memory usage report in every build (developer change, no effect on the device).

Kits, patterns, projects and the MIDI implementation are unchanged.

Installing

1. Download LXR_OpenElixir-02_V0.1.img below.
2. Copy it to the top folder of the SD card and delete any other LXR*.img files there.
3. Switch the LXR-02 off, insert the card, hold the encoder button and switch it on. Keep holding
   until "LXR Updater" appears.
4. Wait for "Update OK!". The device restarts with the new firmware.

To go back, install the official firmware update from Erica Synths the same way.

The .hex and .elf files are for programming and debugging with an ST-Link; you don't need them for
a normal update.