Evaluation of NRF5340 Confirmation of findings

[Moreimic]

Dear Support

I have made the following findings of my evaluation of the NRF5340 with Version 2.1.0 SDK:

-CIS mode has no constant delay at default settings 48-4. According to our measurements it is between 31ms-42ms. Delta is almost 10ms in a lab environment.

-In the current state of the nrf5340_audio sample program its not possible yet to set BN events, Number of IRC, Number of Suebevents, Flush timeout, GC ,PTO.

-CIS mode does not support changes of sampling rate and frame length.

Could you please confirm the following findings.

Kind regards

[dejans]

Hi,

CIS mode has no constant delay at default settings 48-4.

What are default settings 48-4?

In the current state of the nrf5340_audio sample program its not possible yet to set BN events, Number of IRC, Number of Suebevents, Flush timeout, GC ,PTO.

What are you referring to as BN, IRC, GC and PTO?

Best regards,
Dejan

[Moreimic]

Hi,

The 48-4 settings are the codec capability settings according to the Bluethooth Audio Profile (BAP) specification (https://www.bluetooth.com/de/specifications/bap-html/). These profiles are referenced in the audio.h file to set up the LC3 codec accordingly.

- (PTO) Pre-Transmission Offset

- (BN) The Burst Number, which is the number of payloads supplied for transmission in each CIS event.

- (IRC) Immediate Repeat Count

- (GC)Group Count

Best regards,

Moreimic

[dejans]

Hi,

Could you provide debug log from the application core UART?

Best regards,
Dejan

[Moreimic]

Hi,

My question is whether it is possible to set the mentioned parameters with version 2.1.0 SDK. 

Best regards,

Moreimic

[dejans]

Hi,

Regarding your questions
1. If you use analog input, delay should be constant. In case you use USB, note that Zephyr USB stack does not yet support async, which means that both PC and gateway/headset have their own non-synchronized master clocks.
2. Controller is quite flexible in setting the necessary parameters. Parameters that are selected by the controller cannot be set by the application (or host).
3. Changing configuration on the fly is not allowed as this would require tearing down the stream.

Best regards,
Dejan