SPI slave driver - NRFX_SPIS_XFER_DONE event

[Adm]

Hello,

I have a question regarding NRFX_SPIS_XFER_DONE event. Documentation says that this means "SPI transaction has been completed."

I'm curious if this event is triggered on the rising edge of CS signal, or something else triggers it?

[Jørgen Holmefjord]

Hi,

The NRFX_SPIS_XFER_DONE event is generated when the SPIS driver enters the SPIS_XFER_COMPLETED state. This happens when the NRF_SPIS_EVENT_END is generated by the SPIS peripheral. From the SPIS peripheral documentation in the nRF5340 Product Specifications:

"When a granted transaction is completed and CSN goes high, the SPI slave will automatically release the semaphore and generate the END event."

So to sum up: yes, the event is generated right after the CSN pin goes high.

Best regards,
Jørgen