Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F415xx_v2/USART1/CTRL2#0x0
Control register 2
USART identification
Break frame bit num
Break frame interrupt enable
Last bit clock pulse
Clock phase
Clock polarity
Clock enable
STOP bit num
LIN mode enable
https://github.com/cmsis-svd/cmsis-svd-data