The High-Frequency Internal Oscillator (HFINTOSC) is a factory-calibrated, precision digitally-controlled internal clock source that produces a wide range of stable clock frequencies. The HFINTOSC can be enabled through one of the following methods:

The HFINTOSC frequency is selected via the HFINTOSC Frequency Selection (FRQ) bits. Fine-tuning of the HFINTOSC is done via the HFINTOSC Frequency Tuning (TUN) bits. The HFINTOSC output frequency can be divided (post-scaled) via the New Divider Selection Request (NDIV) bits.