Datasheet

SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
376
22.7.17 DMAC Channel x [x = 0..5] Control B Register
Name: DMAC_CTRLBx [x = 0..5]
Address: 0x400C404C [0], 0x400C4074 [1], 0x400C409C [2], 0x400C40C4 [3], 0x400C40EC [4], 0x400C4114 [5]
Access: Read-write
Reset: 0x00000000
This register can only be written if the WPEN bit is cleared in “DMAC Write Protect Mode Register” .
• SRC_DSCR: Source Address Descriptor
0 (FETCH_FROM_MEM): Source address is updated when the descriptor is fetched from the memory.
1 (FETCH_DISABLE): Buffer Descriptor Fetch operation is disabled for the source.
• DST_DSCR: Destination Address Descriptor
0 (FETCH_FROM_MEM): Destination address is updated when the descriptor is fetched from the memory.
1 (FETCH_DISABLE): Buffer Descriptor Fetch operation is disabled for the destination.
• FC: Flow Control
This field defines which device controls the size of the buffer transfer, also referred to as the Flow Controller.
• SRC_INCR: Incrementing, Decrementing or Fixed Address for the Source
31 30 29 28 27 26 25 24
– IEN DST_INCR – – SRC_INCR
23 22 21 20 19 18 17 16
FC DST_DSCR – – – SRC_DSCR
15 14 13 12 11 10 9 8
–– –––––
76543210
–– – –– –
Value Name Description
000 MEM2MEM_DMA_FC Memory-to-Memory Transfer DMAC is flow controller
001 MEM2PER_DMA_FC Memory-to-Peripheral Transfer DMAC is flow controller
010 PER2MEM_DMA_FC Peripheral-to-Memory Transfer DMAC is flow controller
011 PER2PER_DMA_FC Peripheral-to-Peripheral Transfer DMAC is flow controller
Value Name Description
00 INCREMENTING The source address is incremented
01 DECREMENTING The source address is decremented
10 FIXED The source address remains unchanged