Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Nuvoton/M05x_registers/UART0/UA_THR#0x0
UART0 Transmit Holding Register.
Transmit Holding Register By writing to this register, the UART will send out an 8-bit data through the Tx pin (LSB first).
https://github.com/cmsis-svd/cmsis-svd-data