I'm wondering how to use (soft)SPI functionality of my cleanflight flight controller. I want to connect a NRF24L01 module. I can find some references to it in the Cleanflight code, as well as some discussions about it. However, I can't find how I should enable or use this. 

Anybody knows how to do this?

There is no SPI bus available on the SPR F3. There is no such thing as software SPI implemented in the code.

What are you trying to accomplish? Even if you did write your own custom code to implement SPI by bit-banging some unused pins, I doubt you would be able to achieve any of the higher data rates that the NRF24L01 offers.

(27-Apr-2017, 11:09 AM)unseen Wrote: There is no SPI bus available on the SPR F3. There is no such thing as software SPI implemented in the code.

Hmm, I might misunderstand these features in the CLI dump then. Plus I saw a few references in the cleanflight code to NRF24L01.

(27-Apr-2017, 11:09 AM)unseen Wrote: What are you trying to accomplish? Even if you did write your own custom code to implement SPI by bit-banging some unused pins, I doubt you would be able to achieve any of the higher data rates that the NRF24L01 offers.

I am actually trying to build a DIY transmitter and receiver, using arduinos and nrf24l01 modules. I guess this is possible using PWM output with an arduino as receiver anyway, but then I saw some references to direct use of the nrf24l01 on a flight controller. Could not find further info about it though.

Hmm....it would seem there is some support for SPI based receivers in Betaflight, but without a more lengthy analysis, I can't tell you which boards might let you use this feature easily or if it is actually supported.

The SPRacing F3 does not include this code and the only defined SPI interface for this board is SPI bus 2 which is used to access the onboard flash.

There may be other flight controllers out there that would be more appropriate for what you are trying to do and I'm fairly sure you'll need to use a hardware SPI bus if you want to use the receiver chip's 2Mb data rate.