Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Microchip Technology/ATSAME51J19A/SERCOM0/I2CM/CTRLC#0x0
DATA32B=DATA_TRANS_8BIT
I2CM Control C
Data 32 Bit
0 (DATA_TRANS_8BIT): Data transaction from/to DATA register are 8-bit
1 (DATA_TRANS_32BIT): Data transaction from/to DATA register are 32-bit
https://github.com/cmsis-svd/cmsis-svd-data