Datasheet

588
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
35.13 Register Write Protection
To prevent any single software error from corrupting HSMCI behavior, certain registers in the address space can be
write-protected by setting the WPEN bit in the “HSMCI Write Protection Mode Register” (HSMCI_WPMR).
If a write access to a write-protected register is detected, the WPVS bit in the “HSMCI Write Protection Status Register”
(HSMCI_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 HSMCI_WPSR.
The following registers can be protected:
 “HSMCI Mode Register”
 “HSMCI Data Timeout Register”
 “HSMCI SDCard/SDIO Register”
 “HSMCI Completion Signal Timeout Register”
 “HSMCI DMA Configuration Register”
 “HSMCI Configuration Register”