Datasheet

668
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
33.7.5 Register Write Protection
To prevent any single software error from corrupting SPI behavior, certain registers in the address space can be write-
protected by setting the WPEN bit in the ”SPI Write Protection Mode Register” (SPI_WPMR).
If a write access to a write-protected register is detected, the WPVS flag in the ”SPI Write Protection Status Register”
(SPI_WPSR) is set and the WPVSRC field indicates the register in which the write access has been attempted.
The WPVS bit is automatically cleared after reading SPI_WPSR.
The following registers can be write-protected:
 ”SPI Mode Register”
 ”SPI Chip Select Register”