Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Atmel/ATSAM4S4B/CRCCU/MR#0x0
PTYPE=CCITT8023
CRCCU Mode Register
CRC Enable
CRC Compare
Primitive Polynomial
0 (CCITT8023): Polynom 0x04C11DB7
1 (CASTAGNOLI): Polynom 0x1EDC6F41
2 (CCITT16): Polynom 0x1021
Request Divider
https://github.com/cmsis-svd/cmsis-svd-data