I hadn't been able to get any serial monitor feedback except start up sequence with RN52 configuration, even supposedly activating debugmode in CPP ; maybe I'm doing wrong with this.
By the way, as it starts properly while USB powered, it works perfectly in car. It is recognised by car, plays music, change tracks with SEEK buttons... I assume CAN comms are ok.
Removing power from USB let it keep going on.
I gave a try by connecting module directly to car's 12V CDC connector without other pins and it starts !
Under proper CDC connection, it would start if I shorten 3.3V and PWREN pins from RN52 chip... it looks like PWREN signal isn't sent by 328P when connected to audio lines and CAN bus, code seems to stop but why ?
I use v4.1 code revision to ensure nothing related to text scrolling would interfere.
I keep following white stones in the code to understand starting steps...
01' 9.3 SE Conv - AS3 - Nexus 5 Android M 6.0.1 - BlueSaab v4.2 + Amp - Latest CDC repo.