Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Microchip Technology/ATSAML11E15A/SERCOM0/USART/CTRLB#0x0
USART Control B
Character Size
Stop Bit Mode
Collision Detection Enable
Start of Frame Detection Enable
Encoding Format
Parity Mode
Transmitter Enable
Receiver Enable
LIN Command
https://github.com/cmsis-svd/cmsis-svd-data