Datasheet

528
SAM9X25 [DATASHEET]
11054E–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 505
• “DMAC Enable Register” on page 506
• “DMAC Channel x [x = 0..7] Source Address Register” on page 517
• “DMAC Channel x [x = 0..7] Destination Address Register” on page 518
• “DMAC Channel x [x = 0..7] Descriptor Address Register” on page 519
• “DMAC Channel x [x = 0..7] Control A Register” on page 520
• “DMAC Channel x [x = 0..7] Control B Register” on page 522
• “DMAC Channel x [x = 0..7] Configuration Register” on page 524
• “DMAC Channel x [x = 0..7] Source Picture-in-Picture Configuration Register” on page 526
• “DMAC Channel x [x = 0..7] Destination Picture-in-Picture Configuration Register” on page 527
• 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