RE: Latency of 2us when set up the SPIM transmit and receive buffer

Kenneth — Wed, 30 Jan 2019 13:47:33 GMT

Hi,

So I assume you have measured that spim_xfer() takes 2us to execute here, and that there is no delay due to wakeup from sleep that take is part of the 2us.

To speed up transfer you can call spim_xfer() with NRFX_SPIM_FLAG_HOLD_XFER flag to setup the SPI transfer before SS pin. You can get the task to start the transfer by calling nrfx_spim_start_task_get():

https://www.nordicsemi.com/DocLib/Content/SDK_Doc/nRF5_SDK/v15-2-0/group__nrfx__spim#gadb5b212e351bd65958c6be78a957ac65

Then you only need to call the start task to trigger the SPIM transfer (for instance through PPI or from application).

Best regards,
Kenneth