nRF5340 Audio Application: Two unicast gateways and one headset

[Ladivin]

Hello DevZone community, 

I'm playing with the nRF5340 Audio Application and I'm trying to modify it to support a scenario where one headset can be switching between two unicast gateways. First, ACL connection between the first gateway and the headset is established, so that the audio stream can be configured and started. Then I want to do the same for the other gateway, i.e. to establish ACL connection and if certain conditions are met, stop the first stream and configure and start the new one from the new gateway. The point I struggle with is, that the second ACL connection gets established - I get the connected_cb - but right after that the connection is always ended with BT_HCI_ERR_CONN_LIMIT_EXCEEDED as a result, despite the fact I increased CONFIG_BT_MAX_CONN to 2.

This leads me to a question - is this scenario where one headset (peripheral) can accept more simultaneous ACL connections even supported by LE Audio Controller Subsystem for nRF53?

Thanks!

Lada

[Einarh]

Hello

It is possible to switch between gateways in broadcasting mode:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/nrf5340_audio/README.html#enabling-the-bis-mode-with-two-gateways

In this mode you can change what gateway you're listening to by pressing BTN 5 on the headset:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/nrf5340_audio/README.html#buttons

Note that these aren't "simultaneous connections", from what I understand you simply alter what stream you're listening to.

Best regards,

Einar

[Ladivin]

Hello Einar,

thank you very much for your response. I'm aware of the possibilities of broadcast gateway switching. What I'm trying to find out is, whether I can swich unicast streams - i.e. whether the BLE controller (LE Audio Controller Subsystem for nRF53) supports multiple ACL connections to one peripheral device. 

Thanks,

Lada 

[Einarh]

No I don't believe multiple simultaneous connections to one peripheral device is supported in the audio application:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/nrf5340_audio/README.html#application-modes

Not sure I see the use-case either, what would you get out of this that you couldn't get from broadcast gateway switching?