Datasheet

512
SAM9G25 [DATASHEET]
11032D–ATARM–10-Mar-2014
31.6 Write Protection Registers
To prevent any single software error that may corrupt the DMAC behavior, the DMAC address space can be write-
protected by setting the WPEN bit in the “DMAC Write Protect Mode Register” (DMAC_WPMR).
If a write access to anywhere in the DMAC address space is detected, then the WPVS flag in the DMAC Write Protect
Status Register (MCI_WPSR) is set, and the WPVSRC field indicates in which register the write access has been
attempted.
The WPVS flag is reset by writing the DMAC Write Protect Mode Register (DMAC_WPMR) with the appropriate access
key, WPKEY.
The protected registers are:
 “DMAC Global Configuration Register” on page 514
 “DMAC Enable Register” on page 515
 “DMAC Channel x [x = 0..7] Source Address Register” on page 526
 “DMAC Channel x [x = 0..7] Destination Address Register” on page 527
 “DMAC Channel x [x = 0..7] Descriptor Address Register” on page 528
 “DMAC Channel x [x = 0..7] Control A Register” on page 529
 “DMAC Channel x [x = 0..7] Control B Register” on page 531
 “DMAC Channel x [x = 0..7] Configuration Register” on page 533
 “DMAC Channel x [x = 0..7] Source Picture-in-Picture Configuration Register” on page 535
 “DMAC Channel x [x = 0..7] Destination Picture-in-Picture Configuration Register” on page 536