Configuring SPI -- is the legacy layer required?

RE: Configuring SPI -- is the legacy layer required?

Jørgen Holmefjord — Fri, 24 Aug 2018 08:23:48 GMT

I have reported your suggestions to our SDK team.

RE: Configuring SPI -- is the legacy layer required?

Eric Smith — Thu, 23 Aug 2018 23:25:40 GMT

Before reading your reply, I just tracked it down to the fact that apply_old_config.h uses #ifdef to check for the legacy configuration. That makes it think legacy is enabled if the define is to 0. It should use #if the way almost all other Nordic SDK feature tests work; that way if it is either undefined OR zero, the right thing will happen. In my opinion, this is still a defect in the SDK.

RE: Configuring SPI -- is the legacy layer required?

Jørgen Holmefjord — Mon, 06 Aug 2018 06:25:53 GMT

Just remove the legacy SPI driver config from sdk_config.h and you will be fine. apply_old_config.h will overwrite the config if the SPI_ENABLED config is defined, so you should make sure it is not defined at all. This can only be achieved by removing the config from sdk_config.h.

You do not need the legacy config when using the new nrfx drivers, so removing this is completely safe.

RE: Configuring SPI -- is the legacy layer required?

Eric Smith — Fri, 03 Aug 2018 17:57:05 GMT

It may be the _intention_ that the legacy driver is not required, but the configuration for it _IS_ required, due to (in my opinion) a bug in SDK 15.0 apply_old_config.h. Here's what I wrote in response to another ticket (206140) for the same issue:

I have the same problem, and just spent an hour tracking it down. It is caused by the legacy adapter code in apply_old_config.h, which is included from nrf_glue.h, which is included from nrfx.h, which is included from just about everything peripheral-related.

If you're not using the legacy interface, this should leave your NRFX_SPI0_ENABLED etc. unchanged, but unfortunately it does not. If you don't also have SPI0_ENABLED, it redefines NRFX_SPI0_ENABLED to 0. In my opinion, this is a serious defect in the SDK; using the new NRFX drivers shouldn't require having the legacy defines also set.

The workaround is to define SPI<n>_ENABLED to have the same value as NRFX_SPI<n>_ENABLED, to prevent apply_old_config from changing it.

RE: Configuring SPI -- is the legacy layer required?

Jørgen Holmefjord — Fri, 27 Jul 2018 14:44:00 GMT

Hi,

You do not need the legacy layer when switching to the new NRFX drivers.

You should remove the old config for legacy driver from sdk_config.h file, to avoid the configuration to be overwritten by apply_old_config file.

Attached an example that show how this should be done: devzone.nordicsemi.com/.../spi_5F00_nrfx.zip

Best regards,
Jørgen