https://onlinedocs.microchip.com/oxy/GUID-208C8525-948F-497D-8CDD-6E94D4E9DC95-en-US-9/GUID-353A791A-9833-4034-960A-DE56C0D4AB06.html
11.5.6 OSCFRQ
https://onlinedocs.microchip.com/oxy/GUID-5B57F3E2-A025-4F39-AEF3-EEFDC7C17196-en-US-11/GUID-FFD47547-472D-4A97-B494-02C199C2E77E.html
5.6.5 OSCFRQ