Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Microchip Technology/ATSAML11E15A/MCLK/CPUDIV#0x0
CPU Clock Division
CPU Clock Division Factor
1 (DIV1): Divide by 1
2 (DIV2): Divide by 2
4 (DIV4): Divide by 4
8 (DIV8): Divide by 8
16 (DIV16): Divide by 16
32 (DIV32): Divide by 32
64 (DIV64): Divide by 64
128 (DIV128): Divide by 128
https://github.com/cmsis-svd/cmsis-svd-data