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22.2.31 PCI DMA Control Register [3:0] (PCIDCR [3:0])
Bit:
31
—
Initial value:
0
PCI-R/W:
R
PP Bus-R/W:
R
Bit:
15
—
Initial value:
0
PCI-R/W:
R
PP Bus-R/W:
R
Bit:
7
DMAIM
Initial value:
0
PCI-R/W:
R/W
PP Bus-R/W:
R/W
Note: Cleared by writing WC:1. (Writing of 0 is ignored.)
The DMA transfer control register [3:0] (PCIDCR [3:0]) specifies the operating mode of the
respective channels and the method of transfer, etc. This 32-bit read/write register can be accessed
from the PP bus and PCI bus.
The PCIDCR register is initialized to H'00000000 at a power-on reset and software reset.
Writing 1 to bit 0 (DMASTRT) starts DMA transfer. Always re-set the value in this register before
starting a new DMA transfer after completion of a DMA transfer.
When setting the DMASTOP bit, do not write 1'b1 to the DMASTART bit. Also, write the same
setting at the start of transfer to the DMAIM, DMAIS, LAHOLD, IOSEL and DIR bits.
Example: Starting transfer with PCIDCR = H'00000085
Forced DMA termination PCIDCR = H'00000086
If DMA is forcibly terminated with a value other than the setting used in the transfer being
performed, data accuracy is not guaranteed.
Bits 31 to 11—Reserved: These bits always return 0 when read. Always write 0 to these bits.
Rev. 3.0, 04/02, page 862 of 1064
30
29
—
—
0
0
R
R
R
R
14
13
—
—
0
0
R
R
R
R
6
5
DMAIS
LAHOLD
0
0
R/WC
R/W
R/WC
R/W
. . .
19
. . .
—
. . .
0
. . .
R
. . .
R
12
11
—
—
ALNMD10 ALMMD9
0
0
R
R
R/W
R
R
R/W
4
3
—
IOSEL0
DIR
0
0
R
R/W
R/W
R
R/W
R/W
18
17
16
—
—
0
0
R
R
R
R
10
9
DMAST
0
0
R/W
R/W
2
1
DMASTOP DMASTRT
0
0
R/W
R/W
R/W
R/W
—
0
R
R
8
0
R
R
0
0
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