Zephyr - Changing SPI Frequency on NRF52840DK

RE: Zephyr - Changing SPI Frequency on NRF52840DK

Susheel Nuguru — Thu, 13 Apr 2023 14:38:22 GMT

Using an actual SPI peripheral should be easy as there are a lot of samples and articles showing you how to do it. For example an external article for running basic SPI on zephyr can be seen here.

A template can be taken from the NCS playground here.

RE: Zephyr - Changing SPI Frequency on NRF52840DK

Jeff Maigemu — Thu, 13 Apr 2023 08:38:51 GMT

I am currently looking to implement this. Please point me to some examples I could use as a reference

RE: Zephyr - Changing SPI Frequency on NRF52840DK

Susheel Nuguru — Tue, 11 Apr 2023 07:52:59 GMT

Bitbanging does not go well with throughput achieved on embedded cores. Why wont you use an actial SPI peripheral that comes with our SoC?

RE: Zephyr - Changing SPI Frequency on NRF52840DK

Simonr — Mon, 03 Apr 2023 06:05:26 GMT

Susheel is out of office for the Easter holiday, and will get back to you on April 11th. Thank you for your patience!

Best regards,

Simon

RE: Zephyr - Changing SPI Frequency on NRF52840DK

Jeff Maigemu — Fri, 31 Mar 2023 12:33:52 GMT

Thanks for your reply. How would you suggest that I configure my SPI to achieve the maximum rates then?

RE: Zephyr - Changing SPI Frequency on NRF52840DK

Susheel Nuguru — Thu, 30 Mar 2023 14:46:43 GMT

I have not tried the SPI bitbanging sample, but I am quite certain that bit banging is a slow process and will take many CPU cycles to bang just one bit of the serial protocol. I have not profiled this serial communication but 12.5Khz could be on the max end of what you can achieve with bit banging for SPI. I cannot say it for sure, since I have not tested this but I do not think you can achieve very high rates compared to 32MHz HFCLK.