Issue with Channel Sounding modes on nRF54L15DK

RE: Issue with Channel Sounding modes on nRF54L15DK

SwRa — Fri, 20 Feb 2026 10:32:55 GMT

Hi Sandy,

Sorry for the delay.. The issue is that you are not using a valid combination of main mode and sub mode types (Main mode 3 and sub mode 1). See here for the valid combinations: https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/low-energy-controller/channel-sounding.html#UUID-5bd41abf-c6ad-a020-d3cf-e6ad8434fc66_N1690580327249

Try changing it as follows:

.main_mode_type = BT_CONN_LE_CS_MAIN_MODE_3,
.sub_mode_type = BT_CONN_LE_CS_SUB_MODE_UNUSED

Best Regards,

Swathy

RE: Issue with Channel Sounding modes on nRF54L15DK

SwRa — Mon, 21 Jul 2025 14:39:35 GMT

Hi Sandy,

I will need to check this.. I will get back to you with the updates.

Regards,

Swathy

RE: Issue with Channel Sounding modes on nRF54L15DK

sandysparky — Thu, 17 Jul 2025 13:46:42 GMT

Hi Swathy,

Thanks for the quick response.

Yes, I had already tried enabling them on proj.conf:

CONFIG_BT_CTLR_SDC_CS_STEP_MODE3=y
CONFIG_BT_RAS_MODE_3_SUPPORTED=y

I did this on both the initiator and reflector boards. I also verified the configuration by running the shell command:

cs read_local_supported_capabilities

And got the expected response:

Mode 3 supported: Yes
RTT AA only supported: Yes

So it does indicate that Mode 3 is supported, but unfortunately the issue still persists despite this. Let me know if there’s anything else I should try or check.

Best regards,

Santhosh

RE: Issue with Channel Sounding modes on nRF54L15DK

SwRa — Thu, 17 Jul 2025 13:34:28 GMT

Hi Sandy,

MAIN_MODE_3 is supported on nRF54L15. Could you try adding the following config: CONFIG_BT_CTLR_SDC_CS_STEP_MODE3=y and see if it works.?

See here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrfxlib/softdevice_controller/doc/channel_sounding.html#cs_kconfigs

Best Regards,

Swathy