I would like to ask whether it is possible both to record and to play back sound on Primer2 simultaneously (i.e. using Primer2 as some kind of sound effect device)?
It could be possible in 'voice mode', by using both I2S2 and I2S3. At the moment (in Circle OS), 'voice mode is used for recording, but 'audio mode' is used for playing, and both cannot be used simultaneoulsy. We never used 'voice mode' for playing.