Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Atmel/AT91SAM9G25/UART1/SR#0x0
Status Register
Receiver Ready
Transmitter Ready
Overrun Error
Framing Error
Parity Error
Transmitter Empty
https://github.com/cmsis-svd/cmsis-svd-data