Mix BLE audio and custom BLE Characteristic

[bojan]

Hello, everyone!

I'm interested to know about the possibility of mixing BLE audio and custom BLE Characteristic in one single nRF5340 application.

For example, we would like to mix:

1. A True Wireless Earbud (TWS) BLE audio topology with mono output and microphone input for two-way audio communication and
2. Custom BLE Characteristic that will be used for transferring data collected from various sensors

If there is no possibility to mix BLE audio with the Custom BLE Characteristic for data transfer, would it be possible to have run-time reconfiguration and change the desired BLE profile during run time?

I know that we must have LE Audio Controller for nRF53 app binary implemented in the network core of nRF5340 for BLE audio profile. Is this any blocker for using custom BLE characteristic for data transfer?

Thanks in advance for your time and efforts.

Sincerely,
Bojan.

[Hieu]

Hi Bojan,

Yes, it is possible to setup a custom GATT Characteristic when you are using the BLE Audio feature together with the LE Audio Controller.

Could you please give a little more details on which devices have to connect to which for the sensor data in your example? There is a limit on the number of concurrent connections a device with the LE Audio Controller can maintain.

Hieu

---

Due to Christmas & New Year Holidays, our team is currently understaffed and will take longer than usual for responses and follow-ups. Our apologies for the inconvenience.

[bojan]

Hello, Hieu 

Sorry for the late reply.

We would basically have one single BLE Central device (e.g the smartphone) that will be used to establish a connection with nRF53.

We would need to:

1. Establish two-way audio communication (TWS topology) between nRF53 and BLE Central
2. Collect the data from various sensors and transfer them to the BLE Central device using a custom-defined BLE Service with multiple custom BLE Characteristics.

Those two should exist in parallel (ideally) or it would be nice if we could reconfigure the BLE part during run-time to run either in TWS BLE audio mode or in data collection mode.

I hope it's now clear what we want to achieve.

Sincerely,
Bojan.

[Karl Ylvisaker]

Hello Bojan,

Hieu is unfortunately unavailable for a couple of days, so I will follow this up in his absence.

bojan said:

Anyway, good thing is that we could stop some of the sensor readings when we want BLE audio link.

Great, then you can send the sensor data over the ACL link when the audio is paused and visa versa without issue.

bojan said:

What would be the code we need for the network CPU in this use case?

The network core must be programmed with the precompiled LE Audio Controller, so you do not need to write any code for the network core specifically.
Please note that we are aware of a stability issue with the current controller when the ACL connection interval is not a 2x multiple of the ISO interval, so please make sure to only use a 2x multiple of the ISO interval for your ACL connection interval to avoid this.
You should also avoid updating the ACL connection interval while the ISO is transferring audio for the same reason, if possible.
We are of course working on a fix for this already, but just keep it in mind for the time being! :)

Best regards,
Karl

[bojan]

Thanks for the update, Karl Ylvisaker .

For transferring sensor readings, we need a connection interval of at least 12.5ms (10 x 1.25).

What is the value of the ISO interval? Is it something fixed or flexible? Can we make it to be 5 x 1.25ms?

Best regards,
Bojan.

[Karl Ylvisaker]

Hello Bojan,

bojan said:

Thanks for the update, Karl Ylvisaker .

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

The ISO interval used is primarily 10 ms currently, but since you are stopping the ISO stream before you start your sensor data transfer then this consideration does not apply, so you can use whichever connection interval as you would like, just as with a regular BLE (non-ISO) connection.

Best regards,
Karl

[pal_722]

Hi all, 
I am working on a similar application too, and wish to know how to setup iso connection between nrf5340 audio dk and mobile?

Any help would be of great use!
Thank you so much in advance

[AHaug]

Hi,

Please create a new ticket for your own questions and we'll look into the case :) 

Closing this discussion since it is over 2 years old and it was started by someone else.

Kind regards,
Andreas