Debugging SPI problems on NXP K66
I've worked with the K64 - it is a powerful beast :)

Checklist:


Are you using the right SPI peripheral? SPI0, SPI1, SPI2 etc.
Is the clock to the peripheral enabled? (if not you should have got a hard fault)
Is the right pin multiplexing option selected? The most likely issue in my opinion.
Is the driver correct? For example: after you write the SPI data register you have to wait (poll a flag) until the byte is shifted out before writing another byte.