confusing about nrfx. How should I use it without legacy with old and do I need it?

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Simon — Tue, 21 Jul 2020 19:39:25 GMT

I have updated my earlier answer. Please check it out.

Best regards,

Simon

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

robwasab — Sat, 18 Jul 2020 06:41:20 GMT

Here's an idea,

This is coming from my current predicament where I was using the nrfx_clock driver, but found that it didn't implement the request and release API I need to share the resource between different modules of code, however, the nrf_drv_clock did implement it.

The thing is, is that the nrf_drv_clock driver is implemented as actual C code and calls the nrfx functions. The "deprecated" drivers, where you should use nrfx, are the ones where the distinction is simply a macro.

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Patrick — Wed, 27 Mar 2019 13:16:00 GMT

There is a nrfx_config.h located in <sdkdir>/modules/nrfx/templates/<board>

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Jake — Tue, 26 Mar 2019 21:36:22 GMT

Are there peripheral examples using purely nrfx drivers with the legacy defines already cleaned up?

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Simon — Tue, 12 Mar 2019 15:34:01 GMT

UPDATE 7/21/2020:

There have been some discussions internally and it seems like the answer provided below is not correct. There are no strong recommendations to use the NRFX drivers.

Earlier in the SDK 15.2.0 NRFX migration guide, it said the following:

"The legacy layer will no longer be supported in the future SDK releases."

However, in the SDK 17.0.0 NRFX migration guide, this is updated to the following:

"The migration process is not required and often results in exactly the same functionality. Consider migration only if you want to take advantage of the new features offered by nrfx."

You are right Patrick, the answers regarding the use of the NRFX vs. the legacy drivers are not consistent. However, the SDK 15.0.0 migration guide strongly recommends to use the NRFX API for new applications. The justification is that the legacy layer will be deprecated and removed in future SDK releases.

My recommendation is that one should use pick the drivers that fits their specific product and future plans. If you are planning to update your solution as new SDK's are released and want to decrease the amount of future work, you should use the NRFX drivers. If not, just use the SDK as it is, with the legacy "glue" layer.

Regarding Einar's answer, you should take a look at the SDK 15.0.0 migration guide, where all the nrf_drv drivers which can't be easily swapped with NRFX functions, are listed. E.g. the nrf_drv_clock driver contains SoftDevice dependent code.

The migration to NRFX drivers shouldn't be too difficult, if you follow the appropriate migration guide correctly you should be good, since you will be warned about the drivers that is difficult/can't be easily switched out, and the corresponding legacy drivers should be used.

Best regards,

Simon

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Patrick — Mon, 11 Mar 2019 17:37:26 GMT

Hi Simon,

Here is the thread I was referring to. My reply may have been overly general as I made the comment without going back to look at the linked thread. A more accurate statement on my part would have been that not all of the nrfx drivers play nicely with the SoftDevice. I think Einar also implies that there is really no reason to switch from nrf_drv_* to nrfx_*, and I have seen this point of view in other threads that I do not have time to find. This has not stopped me from using nrfx_* in some of my libraries but it does create confusion.

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Simon — Mon, 11 Mar 2019 16:00:20 GMT

I could not find the answer you referred to (about nrfx not being SoftDevice safe). Could you provide a link?

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Simon — Mon, 11 Mar 2019 15:57:58 GMT

The approach seems correct. Remember to remove/comment all legacy defines in sdk_config.h (as explained here), if not it will override the NRFX defines.

Best regards,

Simon

RE: confusing about nrfx. How should I use it without legacy with old and do I need it?

Patrick — Sat, 09 Mar 2019 18:14:05 GMT

Depending on who responds from Nordic you’ll get a number of different answers. The last answer I saw a few weeks ago suggested that nrfx shouldn’t be used because it isn’t SoftDevice safe. Apparently nrfx is lower level than nrf_drv and nrf_drv uses nrfx behind the scenes. It’s confusing as hell because apparently nrf_drv being “depreciated” doesn’t really mean it shouldn’t be used according to Nordic.