currently I'm developing generic SPI driver for S32K devices for use in slave mode. My intention is to perform the whole handling without usage of DMA and interrupts. The issue I'm facing now is end of frame detection. In order to read Receive FIFO I need to know if it contains data of the whole frame. I tried to use SR[FCF] bit, which according to Reference Manual should indicate the end of frame, when PCS negates. Unfortunately it doesn't seem to work this way. It is not set, though PCS is negative. How does this bit really work?