Low IRQ and adl_audiostreamlisten issue

Hi Everybody,

I’m trying to transfer data using voice call. I would like to send ascii char (mapped into
PCM sample) from one modem to another.
Therefore, I need to record PCM stream using adl_audiostreamlisten function.

I started from pcm_record_play sample but I noted that Low Irq handler is not called
(where the receiving buffer is written).
Only High Irq handler is called and the resulting buffer is empty.

I search in the forum and some guys seem to success in recording PCM stream but I
can’t understand how this function and irq work.

Does anyone has expirence on this matter?

Thank you.

Best Regards,
Davide Tasca

That doesn’t sound like a very good idea - please elaborate on your goal


Trying to elaborate…

Step 1: modem 1 starts a voice call

Step 2: modem 2 answers the voice call

Step 3: modem 2 starts listen to an audio PCM stream

Step 4: modem 1 sends a PCM stream which values are ascii char.
Example: “Hello” means “0x48, 0x65, 0x6C, 0x6C, 0x6F”

Step 5: modem 2 receives the stream and save it

The Problem:

Step 1, 2, 3 and 4 seem to work correctly, but Step 5 fails because I expect
that function adl_audioStreamListen call for LOW IRQ callback, but it is
never called (tried to put a debug trace into the callback). Only the HIGH IRQ callback is
called at the end of listen, where I check that recorded buffer is empty

Thank for assistance if anybody could help.


No: that describes the steps you’re taking - not the goal you’re trying to achieve!


I don’t think this is going to work - GSM speech coding is not linear - so I think you probably need to go back to your goal, and re-think the steps to achieve it…