Datasheet

822
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
39.7.10 Write Protection Registers
To prevent any single software error that may corrupt USART behavior, certain address spaces can be write-protected
by setting the WPEN bit in the USART Write Protect Mode Register (US_WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the USART Write Protect Status Register
(US_WPSR) is set and the WPVSRC field indicates in which register the write access has been attempted.
The WPVS flag is automatically reset by reading the USART Write Protect Mode Register (US_WPMR) with the
appropriate access key, WPKEY.
The protected registers are:
z “USART Mode Register”
z “USART Baud Rate Generator Register”
z “USART Receiver Time-out Register”
z “USART Transmitter Timeguard Register”
z “USART FI DI RATIO Register”
z “USART IrDA FILTER Register”
z “USART Manchester Configuration Register”