19:49 <Siegurd> Hi! I'm searching for fastest SPI communication method on BBB with AD7771 ADC. I need 30MHz speed and that CS pin working without delays (when DRDY interrupt occur I need to send 8 packets covered by SC LOW state in 8us time window). For now, when I use https://github.com/deeplyembeddedWP/BeagleBone-SPI-Library/blob/master/SPI_Library/SPI.h I reach

19:50 <Siegurd> 30MHz speed but CS pin is triggered way to slow (14.5us before and 4.3us after transaction of 4 bytes, for some reason transaction took 4.25us instead of 1.06us). Maybe is there a PRU library for fastest SPI transactions or GPIO triggering or some "RAW" kernel SPI layer that I can communicate directly from C/C++? I've found this 2 example but the

19:50 <Siegurd> both have low maximum CLK speed (up to 10MHz): https://gitlab.mpcdf.mpg.de/mpq-polarlab/pru-spi/-/blob/master/pru_spi.c and https://github.com/giuliomoro/bb-pru-spi-duplex/blob/master/pru-spi-master.p looking forward to your replay.

19:56 <Siegurd> I also found AD7771 ADC Linux driver but I don't know how to integrate it in BBB: https://github.com/analogdevicesinc/linux/blob/ad7779_driver/drivers/iio/adc/ad7779.c#L426