11.3.3 Fail-Safe Condition Clearing
The Fail-Safe condition is cleared after a device Reset, execution of a
SLEEP
instruction, or a change to the NOSC/NDIV bits. When switching to the external oscillator or PLL, the Oscillator
Start-up Timer (OST) is restarted. While the OST is running, the device continues to
from HFINTOSC. When the OST expires, the Fail-Safe condition is cleared after
successfully switching to the external clock source.Important: Software must clear
the OSFIF bit before switching to the external oscillator. If the Fail-Safe condition
still exists, the OSFIF bit will be set again by module hardware.