Regarding nordic SPI driver implicitly using DMA

[Ubaid_M]

Hi,

Request confirmation that nCS nordic SPIM & SPIS drivers implicitly use DMA,
I found the response as in: https://devzone.nordicsemi.com/f/nordic-q-a/83593/zephyr-rtos-spi-dma-sample-code

Hence the query, request you to also point to me towards DMA usage code snippets in driver files "spi_nrfx_spim" & "spi_nrfx_spis", or in nordic legacy SPI drivers, so that I can justify my development.

Thanks,

Ubaid 

[Karl Ylvisaker]

Hello Ubaid,

The SPIM and SPIS peripherals use easyDMA explicitly - there is no other option. The drivers for these specific peripherals thus has no influence on the usage of easyDMA.
I do not know which device you are working with, but you could read more about this in the respective device's Product Specification under Peripherals -> SPIM -> EasyDMA.

Best regards,
Karl

[Ubaid_M]

Hi Karl,

Thanks for the confirmation, so I am to understand that in the compatible property, if I am using:

compatible = "nordic,nrf-spis"

or

compatible = "nordic,nrf-spim"

Than it implies I am also using EasyDMA.

I am using nrf52833_dk device.

Thanks,

Ubaid

[Karl Ylvisaker]

Ubaid_M said:

Thanks for the confirmation

No problem at all, I am happy to help!

Ubaid_M said:

compatible = "nordic,nrf-spis"

or

compatible = "nordic,nrf-spim"

Than it implies I am also using EasyDMA.

Yes, when using the SPIM or SPIS peripheral they will always use easyDMA.
Is your intention to avoid using EasyDMA in your application? If so, could you elaborate on this requirement / constraint?

Best regards,
Karl

[Ubaid_M]

Hello Karl,

Karl Ylvisaker said:

Is your intention to avoid using EasyDMA in your application?

Just for the sake of understanding, How can I disable EasyDMA, from SPIM.?

Thanks,

Ubaid

[Karl Ylvisaker]

Ubaid_M said:

Just for the sake of understanding, How can I disable EasyDMA, from SPIM.?

Thank you for clarifying. As mentioned, there is no way to disable EasyDMA for the SPIM peripheral, so if you intend to not use EasyDMA you will have to use the legacy SPI peripheral instead, if available.

Best regards,
Karl