nRF54L15 – Direct Access to Channel Sounding (CSTONES/RTT) Hardware Without SoftDevice Controller

[Abdel0]

I am developing a proprietary 2.4 GHz distance measurement with two-way phase-based ranging and RTT on the nRF54L15.

I intend to control the RADIO peripheral directly, without using the Bluetooth stack or SoftDevice Controller.

The Product Specification documents CSTONES and RTT registers, but I could not find a complete initialization sequence.

Can the CSTONES and RTT hardware operate independently of the SoftDevice Controller?

If yes, is there a register-level example, driver, or documentation covering initialization, timing, and calibration?

If no, are there hardware restrictions that prevent proprietary use?

[PaKa]

Yes, you can run phase based ranging and RTT in proprietary mode by just using the register access. All registers used for Channel Sounding are in the datasheet.

No, there are no register level code examples for doing this, the only supported solution for CS is the SoftDevice Controller.

No, there are no hardware restrictions for using the register level for proprietary use. Only hurdle is building the code and this is a fairly big project indeed.

Any specific reason for not using Channel Sounding?

[Abdel0]

Hi PaKa,

Thank you for your clarification and for confirming that PBR and RTT can be implemented through direct register access.

The main reason for considering a proprietary implementation is financial. I have a startup idea that I would like to develop into a commercial product, but at this early stage, I cannot afford the $12,000 Bluetooth SIG qualification fee.

I would be happy to pay the qualification fee once the business becomes successful. However, right now, I don't even know whether the idea will be commercially viable.

That is why I am exploring a proprietary solution using the nRF54L15's PBR and RTT hardware without the Bluetooth stack.

I understand that this involves considerable development effort, but given my limited budget, I would like to explore this possibility.

Do you happen to know of any alternatives, startup support programs, or other ways to develop and eventually commercialize such a solution without this substantial upfront cost? Any suggestions would be greatly appreciated.

Thank you again for your time and support!

Best regards,
Abdul

[PaKa]

Thanks for the explanation, I can see the thinking.

Unfortunately I do not know of any such programs but someone else on DevZone may do that.

[Emil Lenngren]

The rest of the RADIO peripheral is documented fairly thoroughly in the datasheet. However, the CSTONES and RTT registers don't have any corresponding documentation. Is there any specific reason for that? I suggest those registers get the same thorough documentation as Nordic Semiconductor typically provides for its peripherals.

[Edvin]

Hello Abdel0  and Emil Lenngren ,

The CTONES and RTT registers are not properly documented at this point in time, unfortunately. It is a work in progress, but it has been postponed.

I will ping our R&D and docs team, but I can't give any guarantee for when this will be done.

I am sorry for the inconvenience.

Best regards,

Edvin