NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 911 -
Revision V1.30
NUC97
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CHNIC
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SD Host DMA Control and Status Register (SDH_DMACTL)
Register
Offset
R/W
Description
Reset Value
SDH_DMACTL
0x400 R/W
SD Host DMA Control and Status Register
0x0000_0000
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
DMABUSY
Reserved
7
6
5
4
3
2
1
0
Reserved
SGEN
Reserved
DMARST
DMAEN
Bits
Description
[31:10]
Reserved
Reserved.
[9]
DMABUSY
DMA Transfer Is in Progress
This bit indicates if SD Host is granted and doing DMA transfer or not.
0 = DMA transfer is not in progress.
1 = DMA transfer is in progress.
[8:4]
Reserved
Reserved.
[3]
SGEN
Scatter-gather Function Enable
0 = Scatter-gather function Disabled (DMA will treat the starting address in SDH_DMASA as
starting pointer of a single block memory).
1 = Scatter-gather function Enabled (DMA will treat the starting address in SDH_DMASA as a
starting address of Physical Address Descriptor (PAD) table. The format of these Pads’ will be
described later).
[2]
Reserved
Reserved.
[1]
DMARST
Software Engine Reset
0 = No effect.
1 = Reset internal state machine and pointers. The contents of control register will not be
cleared. This bit will auto be cleared after few clock cycles.
Note:
The software reset DMA related registers.
[0]
DMAEN
DMAC Engine Enable
0 = DMA Disabled.
1 = DMA Enabled.
If this bit is cleared, DMA will ignore all requests from SD host and force bus master into IDLE
state.
Note:
If target abort is occurred, DMAEN will be cleared automatically.