Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Nuvoton/NUC1xx_registers/UART0/UA_FUN_SEL#0x0
Function Select Register.
Function Select Enable 00 = UART Function 01 = Enable LIN Function 10 = Enable IrDA Function 11 = Enable RS-485 Function (Low Density Only)
https://github.com/cmsis-svd/cmsis-svd-data