How to modify NRF_RADIO registers in Bluetooth Application nRF Connect SDK

[HillRipper21]

Hello,

I am getting a bit lost in the pool of different versions and libraries. For simplicity, I just want to achieve a single goal to start which is send a bluetooth packet from my nrf52840 dk to my nrf52833 dk with data whitening turned off (and in the future modify other bluetooth settings). I have followed some examples in the nrf Connect SDK (NCS) to get the boards successfully communicating with each other.

Reading the nrf52840 product specification, I can see there is a bit called WHITEEN in the PCNF1 register I can modify for this effect. I could not find any documentation on how to modify these register values but digging around in the header files I can see some examples of changing the NRF_RADIO registers within the Enhanced ShockBurst (ESB) headers. I can call this code in my application and it appears to change the register value but it doesn't really have any effect as far as I can tell.

Reading around on devzone, it was stated that SoftDevice takes over the RADIO peripheral and it controls all the registers. So I am not sure how to change this property through the softdevice controller on NCS. Again, there is a huge clash of terminology with the nRF5 SDK softdevice, and the NCS Softdevice Controller. Can someone point me in the right direction here please? Some things I am not clear on:

1. Are softdevice used by nRF5 SDK and softdevice controller used by NCS completely different things?

2. How do I change registers listed in the nrf52840 product specification via the softdevice controller? I don't want to have to rewrite an entire bluetooth code stack from scratch to add the customization options I want. I am looking at the softdevice controller documentation, but I don't really see that many customization options beyond a couple of defines https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.6.1/nrfxlib/softdevice_controller/README.html 

3. Should I be using nRF5 SDK instead of NCS? Again, very confusing for developers when there are similar examples in both platforms. Should I be using the Zephyr bluetooth controller instead of the softdevice controller?

[Kenneth]

Hello,

The short story:

There are two different development environement, the nRF5 SDK and the nRF Connect SDK (NCS). For new development I would suggest to start with nRF Connect SDK.

Both nRF5 SDK and NCS can be used with a softdevice (controller) that is tested and qualified by Nordic, the feature it supports depend on which variant you choose:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/softdevice_controller/README.html#softdevice-controller

It's not intended (not possible) that a developer should work with the lower layers of the stack (e.g. RADIO parameters affecting whitening, data-rate and such are not modifieble). This is already implemented and handled by the softdevice controller and following BLE spec, tampering with these settings will likely affect interoperability and also require you to do full re-testing and re-qualifying. I do not see any benfit of this.

NCS also provide a zephyr BLE controller, this is open source, and you may be able to do some modifications there if you really want to, but I highly recommend you not to do any changes if you are making a BLE product. It will affect interoperability and very likely violate BLE specifications, but here is in any case some information about the zephyr BLE controller:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_ble_controller.html#zephyr-bluetooth-le-controller

Kenneth