oroymd Is there a way to use gSerial.write() in a real-time safe fashion to send feedback to the host?
no, that's writing directly to the file descriptor, so it needs to be done from a separate thread. You can use a Pipe to send POD between the two. There already is a Pipe object in the example for Serial. You can use it to also send data back from the audio thread to a new thread. So you can send data from the Rt side with Pipe::writeRt(). You probably want to set the non-rt side to be blocking and have a dedicated thread calling readNonRt() repeatedly, blocking on each call, to minimise the jitter that is typical of polling and non-blocking reads. Whenever valid data is received, pass it to gSerial.write() immediately.
Class documentation: http://docs.bela.io/classPipe.html
