Backup Fast RC (BFRC) Oscillator

The PIC32MZ oscillator system includes a Fail-Safe Clock Monitor (FSCM). The FSCM monitors the SYSCLK for continuous operation. If it detects that the SYSCLK has failed, it switches the SYSCLK over to the Backup Fast RC (BFRC) oscillator and triggers a Non-Maskable Interrupt (NMI). The BFRC is an untuned 8 MHz oscillator that will drive the SYSCLK during an FSCM event. When code at the NMI vector is executed, the software can attempt to restart the main oscillator or shut down the system.