Clearing Interrupt Flags

The individual status flags (IOCxF register bits) will be cleared by resetting them to zero. If another edge is detected during this clearing operation, the associated status flag will be set at the end of the sequence, regardless of the value actually being written.

To ensure that no detected edge is lost while clearing flags, only AND operations masking out known changed bits must be performed. The following sequence is an example of clearing an IOC interrupt flag using this method.

Clearing Interrupt Flags (PORTA Example)

    MOVLW    0xff
    XORWF    IOCAF, W
    ANDWF    IOCAF, F