https://devzone.nordicsemi.com/f/nordic-q-a/75244/nrf_drv_spi_transfer-takes-too-long-timeGood morning, I am working on nRF52840 DK, using nRF5 SDK. I am trying to communicate using SPI. However, I found out that the function nrf_drv_spi_transfer took 10&#181;s, I need to work at high sampling rate to get a good result of my system, thereforeen-USTelligent Community 13Tue, 18 May 2021 07:13:46 GMThttps://devzone.nordicsemi.com/thread/310022?ContentTypeID=1Tue, 18 May 2021 07:13:46 GMT137ad170-7792-4731-bb38-c0d22fbe4515:810b7800-66a7-4525-b8f4-2e8d8aa0b474Susheel Nuguru<p>Hi,</p> <p>Can you also give me some info on how much time it takes for your spi&nbsp;event handler to complete? I see that you rely on a rhd_spi_transfer_done flag to be set in the callback function. What other processing is done in that callback handler?</p> <p>&nbsp;</p> [quote user=""]We can see that within 2.33µs, I have already gotten the response from the slave. However LED0 is still at high level indicating that I am still inside the function nrf_drv_spi_transfer for another 7µs, I would like to know what is the function nrf_drv_spi_transfer waiting for ? Can I reduce this duration ?[/quote] <p>If my math is correct, one CPU instruction on a 64MHz clocked system takes about 15.625 nano second to execute. So in 7 us it can execute 448 instruction. This is not such a big number for the post processing after&nbsp;nrf_spim_task_trigger is called. Maybe you want to fine tune the driver and optimize it even more for your need?</p><div style="clear:both;"></div>