Integrate NUS into BLE Audio code

[Dekel]

Hi,

I'm working with nRF5340 Audio DK.

I'm able to successfully run the audio example in BIS mode (with gateway and headset devices), and also to run the Peripheral UART Bluetooth example separately on my DK.

My goal is to open another BT connection, in parallel to the audio broadcast on my gateway device, to which I can connect with the nRF Toolbox App.

Is it possible? If so, which BT controller should be used? How should proj.conf should look like? What other configurations are required?

I've noticed that the UART example code uses adv.c for advertising, while the audio example code uses bt_mgmt.c.

Thank you,

Dekel

[Karl Ylvisaker]

Hello Dekel,

Is it possible? If so, which BT controller should be used? How should proj.conf should look like? What other configurations are required?

Yes, this is possible - what other requirements do you have to the application / Audio streams?
With the Packetcraft controller there is a hard limitation on the total number of concurrent connections: 2 ISO + 2 ACL, and so you could for instance use this for 2 CIS (1 CIS requires 1 ISO + 1 ACL), or a combination of 1 or 2 BIS + 1 or 2 ACLs.
In case of the latter, you can see an example of how to do this here, but please keep in mind that this is an old example that we do not maintain, but it highlights the general approach you should take to achieve this.

With the SoftDevice Controller there is no such hard limit on the number of concurrent connections, but the downside to using it is that it was very recently updated with ISO functionality, and so it is still experimental and undergoing testing and integration with the nRF5340 LE Audio reference application.
If you would like to give this controller a try (which I recommend), you be on the ncs main, and you must follow the same outline for the NUS inclusion as demonstrated in the referenced example above, but you must also perform these steps when building and flashing the application using the buildprog script:

1. Checkout latest NCS main, since SDC with ISO is merged after NCS v2.5.0, and also some modification are needed for application to run with SDC
   The PR which brings ISO on SDC: https://github.com/nrfconnect/sdk-nrf/pull/12508
   The PR which update buildprog.py for switching between SDC and PCFT https://github.com/nrfconnect/sdk-nrf/pull/12996
2. For using buildprog.py, we can add the command --ctlr="SDC" in the end
   E.g., $ python buildprog.py -c both -b debug -d both -p --pristine--ctlr="SDC"

Please also keep in mind that the SoftDevice Controller still does not have support for DFU with the nRF5340 LE Audio application for the time being.

Best regards,
Karl

[Dekel]

Hi Karl,

I appreciate your quick and detailed response!

First, I've followed these steps:

1. Cloned NCS repository and checked-out on the latest commit (main branch).

2. Initialized West workspace in the repository's directory ("west init" and then "west update", which both completed successfully).

3. As a sanity check, I tried to build the code with the original buildproj.py. Unfortunately, I got stuck with this error:

Therefore, I decided to go with the nRF Toolchain Manager for installing SDK v2.5.1. After successfully achieving that, once again I've done my sanity check. This time it worked. So my first question is what am I doing wrong with the cloned NCS? How can I fix that?

Continuing with NCS v2.5.1 from the Toolchain Manager, I've followed these steps:

1. Replaced 6 files in the NCS with the files from the two pull-requests you've mentioned (3 files from each PR).

2. As a sanity check, I tried to build the code with the new buildproj.py by using this command:

python buildprog.py -c both -b debug -d both -p --pristine --ctlr="SDC"

Unfortunately, I'm stuck with the error of "no such file or directory" for ble_hci_vsc.h, which is included by bt_mgmt_ctlr_cfg.c and bt_mgmt.c:

How should I continue from here?

In addition, I'm not sure how to work with the example code that you've mentioned (NUS integration) - they use there bt_le_adv_start(), compared to bt_mgmt_adv_start() in the audio example code. I assume only one should be used. Which one is it?

Another important thing I've been wondering about:

What are the currently available options for debugging the audio example code? I'm asking this since this is my base-code, and when building & flashing with buildproj.py it's obviously not possible. In addition, when using VSCode with the nRF extension things don't work as expected, which aligns with the note on the example's documentation page.

This is a critical part of my development process.

Thank you,

Dekel

[Karl Ylvisaker]

Hello again,

Dekel said:

I appreciate your quick and detailed response!

No problem at all, Dekel - I am happy to help! :) 

Dekel said:

In addition, I'm not sure how to work with the example code that you've mentioned (NUS integration) - they use there bt_le_adv_start(), compared to bt_mgmt_adv_start() in the audio example code. I assume only one should be used. Which one is it?

This example is very old - it is made using NCS v2.3.0 - so if you wish to run it as is you will need to also use the v2.3.0 code. However, the example still serves as a good illustration of the general approach you must use, and the things you will need to add, in order to merge NUS functionality into the existing nRF5340 LE Audio reference application.

Dekel said:

What are the currently available options for debugging the audio example code? I'm asking this since this is my base-code, and when building & flashing with buildproj.py it's obviously not possible. In addition, when using VSCode with the nRF extension things don't work as expected, which aligns with the note on the example's documentation page.

Which issues are you encountering with the nRF extensions?
You are correct that building and flashing is not supported for the nRF5340 LE Audio application through VSC yet, unfortunately - but the command line and buildprog approaches are very convenient once you get familiar with them! :)

Best regards,
Karl

[Dekel]

Karl Ylvisaker said:

but the command line and buildprog approaches are very convenient once you get familiar with them! :)

Do these approaches allow runtime debugging?

Dekel said:

How should I continue from here?

I would appreciate your comment for that, since I'm stuck at this point.

Thanks,

Dekel

[Karl Ylvisaker]

Hello again Dekel,

Thank you for your extreme patience with this!

I have been out of office for some days, but now I am back.
I am checking some things and I will get back to you with a proper answer to your questions tomorrow!

Best regards,
Karl

[Dekel]

Thanks Karl.

I'll mention that I encountered the "multiple advertising sets" example code, which seems like a good direction to follow. It's not completely strightforward to me, but I've made some progress. I'll keep you updated.

Thanks,

Dekel

[Karl Ylvisaker]

Hello again, Dekel

In the past thread debugging in VSC was not supported by the LE Audio controller, but now that we have ISO support for the SoftDevice Controller there should be no issue using all the tools available in the nRF Connect VSC extension to work with the application, so long as you make sure that you are using the SoftDevice Controller.
I am however having some troubles verifying that all the functionality works as expected, but I suspect that this is due to some recent changes I've made to my development setup, and so I'll keep looking into that.

Dekel said:

I'll mention that I encountered the "multiple advertising sets" example code, which seems like a good direction to follow. It's not completely strightforward to me, but I've made some progress. I'll keep you updated.

Which functionality from the 'multiple advertising sets' example code will you be merging into the nRF5340 LE Audio reference application? Please do not hesitate to ask if you should encounter any issues or questions while working with this! :) 

Best regards,
Karl