When Active Clock Tuning is enabled (ACTEN = 1) and
either the ACTLOCK or ACTORS bits change state (e.g.,
from a Locked to an Unlocked state), the ACT Interrupt Flag
(ACTIF) of the PIR registers is set (ACTIF =
1). If the ACT Interrupt Enable (ACTIE) bit is
set (ACTIE = 1), an interrupt will be generated
when ACTIF becomes set. No interrupts are generated for each
OSCTUNE update unless the
update results in a change of Lock status or Out-of-Range
status.