What is the maximum number of bits that can be transferred in a single SPI operation on a K64? The reference manual says: "The module is in SPI configuration when the DCONF
field in the MCR is 0b00. The SPI frames can be 32 bits long." However, the FMSZ (frame size) field in the SPIx_CTARn register is only four bits wide, which would imply a maximum frame size of 16 bits.