Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Microchip Technology/ATSAML11E14A/OSCCTRL/OSC16MCTRL#0x0
FSEL=4
16MHz Internal Oscillator (OSC16M) Control
Oscillator Enable
Oscillator Frequency Selection
0 (4): 4MHz
1 (8): 8MHz
2 (12): 12MHz
3 (16): 16MHz
Run in Standby
On Demand Control
https://github.com/cmsis-svd/cmsis-svd-data