Minimal PAWR subevent_interval

[CHEN YANG]

Hi,

When I try nrfsdk/zephyr/sample/bluetooth/periodic_adv_rsp, after changing subevent_interval to 8, I meet following error:

*** Booting nRF Connect SDK v2.7.0-5cb85570ca43 ***
*** Using Zephyr OS v3.6.99-0454640d52c7 ***
Starting Periodic Advertising Demo
[00:00:00.392,150] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:00.392,181] <inf> bt_hci_core: HW Variant: nRF53x (0x0003)
[00:00:00.392,211] <inf> bt_hci_core: Firmware: Standard Bluetooth controller (0x00) Version 214.51162 B0
[00:00:00.394,317] <inf> bt_hci_core: Identity: F6:68:C5:DB:A1:04 (random)
[00:00:00.394,317] <inf> bt_hci_core: HCI: version 5.4 (0x0d) revision 0x21fb, manufacturer 0x0059
[00:00:00.394,348] <inf> bt_hci_core: LMP: version 5.4 (0x0d) subver 0x21fb
[00:00:00.397,399] <wrn> bt_hci_core: opcode 0x2086 status 0x12
Failed to set periodic advertising parameters (err -22)

According spec, 8 is a valid value. It seems that Softdevice has some limitation of this value. Please help to tell me how to fix this error.

FYI, my hardware is nrf64349 audio dk, link layer is softdevice.

Thanks,

Chen Yang

[Sigurd]

Hi!

Try reducing the response_slot_spacing , ref https://github.com/nrfconnect/sdk-nrfxlib-next/blob/3a7c771af233c33105966546ca33ea01748b4cc6/softdevice_controller/include/sdc_hci_cmd_le.h#L3828 , 

 * The Response_Slot_Spacing parameter identifies the time between the start of
 * two consecutive response slots. The Response_Slot_Spacing shall be less
 * than or equal to 10 × (Subevent_Interval - Response_Slot_Delay) /
 * Num_Response_Slots. If the Num_Response_Slots parameter is set to 1, then
 * the Controller shall ignore the Response_Slot_Spacing parameter.

[CHEN YANG]

Thanks. Let me check it.