I am using the DSPI drivers supplied with S32DS. The SPI is in Master mode, interfacing to a SPI to UART device with a bit rate of 10Mbps. When I read a buffer of 38 bytes in the SPI to UART device using the interrupt driven DSPI_MasterTransfer() function, it takes 392us between calling the function and receiving the transfer complete interrupt. At this bitrate, this time should be a lot less. Clocking the data at the 10Mbps takes 30.4us. I don't understand what happens with the rest of the time? My guess is that this function should execute in no more than 40us. The MPC5744P is running at 200MHz.