Datasheet

537
SAM9G25 [DATASHEET]
11032D–ATARM–10-Mar-2014
31.7.21 DMAC Write Protect Mode Register
Name: DMAC_WPMR
Address: 0xFFFFEDE4 (0), 0xFFFFEFE4 (1)
Access: Read-write
Reset: See Table 31-4
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x444D41 (“DMA” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x444D41 (“DMA” in ASCII).
Protects the registers:
• “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
• WPKEY: Write Protect KEY
Should be written at value 0x444D41 (“DMA” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN