12.8 INT Pin
The INT pin can be used to generate an asynchronous edge-triggered interrupt. This interrupt is
enabled by setting the External Interrupt Enable (INTE) bit. The External
Interrupt Edge Select (INTEDG) bit determines on which
edge the interrupt will occur. When the INTEDG bit is set, the
rising edge will cause the interrupt. When the INTEDG bit is
clear, the falling edge will cause the interrupt. The External
Interrupt Flag (INTF) bit will be set when a
valid edge appears on the INT pin. If the GIE and INTE bits are
also set, the processor will redirect program execution to the
interrupt vector.