28.5.4 Interrupt Flags - Normal Mode

This flag is set when a serial transfer is complete, and one byte is completely shifted in/out of the SPIn.DATA register. If SS is configured as input and is driven low when the SPI is in Host mode, this will also set this flag. The IF is cleared by writing a ‘1’ to it. Alternatively, the IF can be cleared by first reading the SPIn.INTFLAGS register when IF is set and then accessing the SPIn.DATA register.

The WRCOL flag is set if the SPIn.DATA register is written before a complete byte has been shifted out. This flag is cleared by first reading the SPIn.INTFLAGS register when WRCOL is set and then accessing the SPIn.DATA register.