That makes sense. I have a lot of information about how this thing works, and also a lot of information about things that are still not working about it, I could send you what I've got privately.

I'm finding that there are quirks about its initial handshaking with a device right after you pair with it, and it may work fine on one device and not on another, and I'm trying to figure out how to configure and program the thing so that it works in all cases. This is really tricky.

Example: I found that if I pair up with my car stereo and wait for the pairing to complete, I get a certain set of messages on the console. It doesn't work properly until after I issue an "A2DP STREAMING START" command to the chip, at which point everything works well. Except unless I get the timing wrong of exactly when I send that command. If I send it too soon then it has the old "30 seconds delay" problem on the steering wheel controls. But if I send it later it still has the same problem. And there's no documentation telling me how to do the initial handshaking. Also on my bluetooth headset, audio doesn't stream until I issue the "CALL <btaddr>" command but on the car stereo it streams fine and the "CALL" is automatic. Issuing the CALL command on the car stereo doesn't fix any issues.

Another example, the docs for the A2DP/AVRCP communication seem like they have a lot of good syntax examples, but in practice none of the examples work as expected and the entire system is almost completely inscrutable: https://www.silabs.com/documents/login/application-notes/AN986.pdf (link won't unlock for you until after you sign up for an account at their web site).

For instance, in the document linked above, for the track titles, it looks like what you are supposed to do is register with the headunit to respond to notifications where it requests to get the track titles from you, and then you respond with the track titles. But the syntax is poorly documented and only a single non-working example is given for doing it.

So I'm pulling my hair out on this one. :-)
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Tony Fabris