Datasheet

781
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
36.7.10 Register Write Protection
To prevent any single software error from corrupting USART behavior, certain registers in the address space can be
write-protected by setting the WPEN bit in the “USART Write Protection Mode Register” (US_WPMR).
If a write access to a write-protected register is detected, the WPVS flag in the “USART Write Protection Status Register”
(US_WPSR) is set and the field WPVSRC indicates the register in which the write access has been attempted.
The WPVS bit is automatically cleared after reading the US_WPSR.
The following registers can be write-protected:
 “USART Mode Register”
 “USART Baud Rate Generator Register”
 “USART Receiver Time-out Register”
 “USART Transmitter Timeguard Register”
 “USART FI DI RATIO Register”
 “USART IrDA FILTER Register”
 “USART Manchester Configuration Register”