Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32l5/STM32L552/LPUART1/RQR#0x0
Request register
Send break request
Mute mode request
Receive data flush request
TXFRQ
https://github.com/modm-io/cmsis-svd-stm32