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SA-1110 Developer’s Manual 211
Peripheral Control Module
11.6.1 DMA Register Definitions
Each DMA channel is supported by six 32-bit registers as part of the DMA controller hardware.
These registers are the DMA device address register (DDARn), DMA control/status register
(DCSRn), DMA buffer A start address (DBSAn), DMA buffer B start address (DBSBn), DMA
buffer A transfer count (DBTAn), and DMA buffer B transfer count (DBTBn). (The n is a value
from 0 to 5 and is the channel number.) A register summary including physical addresses is
provided in Section 11.6.2.
11.6.1.1 DMA Device Address Register (DDARn)
The DDARn is a 32-bit read/write register containing channel information regarding the target
device. Writes to this register are blocked if the RUN bit in the DCSRn is one. The following figure
shows the format for this register. Question marks indicate the values are unknown at reset. Valid
values for DDARn are shown in Table 11-6.
1
“Partial” means certain bits in the address are assumed to be zero. The DA [31:8] field is constructed as follows:
DA[31:28] = Device port address [31:28].
Device port address 27:22 is assumed to be zero.
DA[27:8] = Device port address [21:2].
Device port address 1:0 is assumed to be zero.
DDARn Read/Write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
DA 31
DA 30
DA 29
DA 28
DA 27
DA 26
DA 25
DA 24
DA 23
DA 22
DA 21
DA 20
DA 19
DA 18
DA 17
DA 16
DA 15
DA 14
DA 13
DA 12
DA 11
DA 10
DA 9
DA 8
DS 3
DS 2
DS 1
DS 0
DW
BS
E
RW
Reset ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Bits Name Description
0RW
Device data transfer direction (read/write).
0 = Transfer is a write (memory to device).
1 = Transfer is a read (device to memory).
1E
Device endianess.
0 = Byte ordering is little endian.
1 = Byte ordering is big endian.
2BS
Device burst size.
0 = Four datums per burst.
1 = Eight datums per burst.
3DW
Device datum width.
0 = Datum size is one byte.
1 = Datum size is one half-word.
7..4 DS 3..0
Device select.
This field is programmed to point to the desired device.
31..8 DA 31..8
Device address field.
This field is a partial address of the data port of the device currently being serviced.
1