How to let nRF5340 Audio DK device work as Host?

[John81]

Dear nRF team,

My requirement is that this device works as Host, and it can communicate with controller device through UART, so I have several questions:

1. How to build an Host image for this device?

2. Which pins are used for UART? If default set doesn't work, how can I configure the pins for it?

3. Can this Host used for music or call business just by UART?

Best regards,

John

[John81]

BTW, UART mentioned in Q2 and Q3 is HCI UART.

[John81]

Dear Team,

I have generated a hci uart hex file successfully following steps in

One of nRF5340 audio DK not working at 1M hci uart - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

and uart1 works as HCI UART, which pins are p1.08, p1.09, p1.10 and p1.11.

But I am not sure how to test these functions below with a LE Audio Controller device connected by HCI UART:

1. Music through CIS with Mobile Phone that supports LE Audio.

2. Call through CIS with Mobile Phone that supports LE Audio.

3. Music through BIS with Mobile Phone that supports LE Audio? If the phone doesn't support, with bluez or others ?

Would you please give me some advices? Thanks!

Best regards, 

John

[ovrebekk]

Hi John

Is there any particular reason why you need to split the controller and host between two nRF5340 devices? With its dual core design the nRF5340 is optimized to run the controller on the network core and the host on the application core. 

For regular Bluetooth LE applications it should be possible to split the controller and host between two physical devices like you describe, but unfortunately LE Audio is a bit different in that the controller and host needs very accurate synchronization in time in order to tune the audio clock on the receiver to the clock of the transmitter (to avoid audio buffer overrun or underrun). 

In our solution this is handled by synchronizing the RTC counters in the network core and application core using the DPPI controller, and this system is not easy to adapt to a solution where the host and controller resides on different devices.

If you can provide more information about your product and why you need to split the host and controller between two devices I will see if I can find any solution or workaround.    

Best regards
Torbjørn

[John81]

Hi Torbjørn,

Thanks for your reply.

As I have a LE audio controller device, and I want to test music and call functions on it.

I found v2.5.0 had hci_uart project, as you know we can test music and call function by hci uart on classic BT, so I suppose whether I can test LE Audio by hci uart.

So is there any other methods to let it work? any suggests are grateful.

Best regards,

John

[ovrebekk]

Hi John

You could try to disable drift compensation and presentation compensation here in order to disable the synchronization feature. Simply update these two lines of code in audio_datapath.c to set the fields false rather than true. 

This is likely to introduce artifacts in the audio, but that might be acceptable for your testing. 

Regarding running the host only on the nRF53 this has never been tested for audio applications, but there is some general information here about how to run the Bluetooth host only. Just navigate to the chapter called "Host-only build". 

Best regards
Torbjørn