Isochronous channels on nRF5340

[lCannon]

Does nRF Connect SDK V2.4.0 support Isochronous channels over BLE?  My understanding is it does.  In fact there is now an Nordic audio DK that uses it to stream audio.  The centeral_iso example fails with the error "Failed to create CIG (-134)" when starting.  Other ISO examples fail similarly and do not work  Should these examples be working?  Are there any working ISO examples?  If there are not, how would the audio DK work?

Could changes be made to the net core configuration to get the examples to work by adding a child_image folder and hci_rpmsg.conf file?

Inside the SDK at \v2.4.0\zephyr\samples\bluetooth\hci_rpmsg\ there are many configurations for ISO usage.  Do any of them work with any examples?

Thank you

[dejans]

Hi,

lCannon said:

How can a debug session be started without writing over the net core. There is no child_image folder created yet the GENERATED_CP_NETWORK_merged_domains.hex file is created and I think installed.

Child image folder should be created manually before building the application.

lCannon said:

Can you verify the proper command or series of command to write the net core and at what time it should be done?

There is no special command to be run for writing to the net core. Previously, the assumption from my side was that you would use nrf5340_audio board and audio controller, but you do not need to flash anything to the net core in this case since you use standard Zephyr controller.

lCannon said:

Should the centeral_iso and peripahl_iso examples work with the child image file created and modified as stated or are they unsupported?

4) When starting the peripheral_iso example with the chile image changes the error 

    Bluetooth initialized
    Unable to register ISO server (err -134)

is generated.  Are there other changes for the peripheral_iso example?

For both samples (central_iso and peripheral_iso) you would need to create child_image folder and hci_rpmsg.conf inside it manually. Only the contents of these files are different, as shown below.

in hci_rpmsg.conf of peripheral_iso

CONFIG_BT_LL_SW_SPLIT=y
CONFIG_BT_CTLR_PERIPHERAL_ISO=y

in hci_rpmsg.conf of central_iso

CONFIG_BT_LL_SW_SPLIT=y
CONFIG_BT_CTLR_CENTRAL_ISO=y

I have tested both samples successfully using nrf5340dk_nrf5340_cpuapp as the build target.

If you have any further questions related to Zephyr controller and ISO support, please use Zephyr Discord Channel.

Best regards,
Dejan