Multiple services in GATT profile with Zephyr OS

RE: Multiple services in GATT profile with Zephyr OS

runsiv — Wed, 09 Aug 2023 09:24:42 GMT

I'm sorry I was not able to provide the service that would be able to be off help.
I will give the feedback regarding how service discovery to the course makers. It would be helpful since the documentation is to be honest, not the easiest to navigate, and a single sentence would make everything more clear. I tried to see if I could find any good explanations in our documentation but I was not able to find it

Regards

Runar

RE: Multiple services advertising with Zephyr OS

bem22 — Tue, 08 Aug 2023 19:32:26 GMT

I figured this out by myself.

If you want to add multiple services to the GATT Profile you don't necessarily need to advertise them. This was unclear to me and it did not make sense.

You can add any number of services and characteristics and they will be discovered after connection. The advertisement of the UUID for service has the purpose of filtering the scanned devices. Again, very unclear to me from the wording in the BLE Course - or my English is lacking - who knows?

The answer for coding multiple services without advertising them can be found in ncs/v2.x/zephyr/samples/bluetooth/peripheral

Here's a screenshot of the peripheral app to which I added the Nordic LBS service

RE: Multiple services advertising with Zephyr OS

bem22 — Tue, 08 Aug 2023 11:26:17 GMT

I'm sorry to say but your comment passes as very shallow

I've run through the course myself and it's unclear whether I could expose multiple services. The course/academy does not cover multiple services or even hint at multiple service discovery so this is why I'm coming here.

To come back to the problem at hand, I'm trying to understand how can I implement this for my development and how Sony managed it to do in those headphones where there appear to be 11 services after connection:

Am I really asking for too much here?

RE: Multiple services advertising with Zephyr OS

runsiv — Tue, 08 Aug 2023 08:28:18 GMT

I think our academy can describe this better then I, so I would have a look here.

[quote user="bem22"]I would like to know whether there is a different method of discovering the services post connection to the device[/quote]

At this point you already have the information, you just need to read it out.

Regards

Runar

RE: Multiple services advertising with Zephyr OS

bem22 — Mon, 07 Aug 2023 13:24:18 GMT

Oh, I understand.

So that 31 bytes is really the limit.

I would like to know whether there is a different method of discovering the services post connection to the device - much like how the characteristics get discovered. I realized that I don't need the services to be discovered during advertising - but just have them as a structural hierarchy. What do you think?

RE: Multiple services advertising with Zephyr OS

runsiv — Mon, 07 Aug 2023 12:21:23 GMT

Hi,

I recommend looking into this sample for multiple service advertising

Regards

Runar