Quite interesting. Nothing too surprising here - TDM, a few clock lines and some communication channel. Really good description of the reverse engineering process and a nice end result. A few weeks ago I was hoping that someone could give me pinouts for the WING expansion slot, because I'd love to be able to use hard drives instead of SD cards to record things. This gives me new hope that something like this is possible - Receiving some TDM signals is not too magical (although it will probably be 8x TDM with 8 channels for the WING), so I might actually investigate this when things calm down a bit here.
Writing to a disk with FS, likely over USB, will require some beefy CPU anyway, so it might make sense to look in the direction of interfacing some SBC/SoC with TDM, and doing the rest in an optimized buildroot OS. That's kind of what the Dante Brooklyn-II cards do anyway. Even weirder (and improbable) thought: Might it be possible to modify a firmware of a Brooklyn-II/III module to write the audio to some NFS share? It's already running Linux anyway, and I'm sure that there's some SDK available somewhere
