Anyway, Open source isn't really necessary.
A simple 'Native Mode' that let user get all the interaction informations from the BeatStep and messages to control every visual feedback on it
It has been done before on the Launchpad, Monome, Apc40, Padkontrol, etc...
Many custom mod have been done with those very simple access
It generally consist in a series of:
- midi notes to light up any Led with the color parameter in the velocity value (like it was done on the launchpad)
- same midi notes, aftertouch for the input pads
- simple midi cc for the knobs
- obviously the 7segment Led display is gointg to need Sysex or NRPN messages (better for ableton users)
Then even users with no C++/harware knowledge can easily build whatever they want without any risk to compromise the hardware's firmware.
Making a new sequencer, would be possible through :
- Max
- Pure Data
- Max4live
- Live midi remote script
- Processing
- Arduino
- Raspberry Pi
- ...
Actually whatever can execute code and send/receive midi.