Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Nuvoton/M05x_registers/UART0/UA_FUN_SEL#0x0
UART0 Function Select Register.
Function Select Enable 00 = UART Function. 01 = Reserved. 10 = Enable IrDA Function. 11 = Enable RS-485 Function.
https://github.com/cmsis-svd/cmsis-svd-data