If I put the DSP in play mode (B_PLAY_UL) I can send
some garbage on
dsp_api.ndb->a_du_1 and the peer will play it, but if I peek the data at
dsp_api.ndb->a_du_0, it's null filled. If I revert the play mode, I can see
data on dsp_api.ndb->a_du_0.
I guess the play ul both enables the tx from a_du_1 and also disables
the audio compression stuff ...
You can try to modify the content of a_du_0 at the time of the
interrupt without leaving but I'm not sure it'll work or if the dsp
will already have taken the data ...
Cheers,
Sylvain