PCI-SIO4 User Manual
General Standards Corporation
8302A Whitesburg Drive Huntsville, AL 35802, Phone: (256) 880-8787
49
D11
Local Addressing Mode
A ‘1’ indicates local addresses LA [31:2] to be held constant.
Note: This bit should always be set to ‘1’ (no address increment).
D12
Demand Mode Enable
A ‘1’ causes the DMA controller to operate in Demand Mode.
In Demand Mode, the DMA controller transfers data when its DREQ# input is asserted.
The DMA controller transfers Lwords (32bits) of data. This may result in multiple
transfers for an 8 or 16 bit bus.
D13
Write and Invalidate Mode for DMA Transfers
When set to 1, PCI 9080 performs Write and Invalidate cycles to the PCI bus. PCI 9080
supports Write and Invalidate sizes of 8 or 16 Lwords. The size is specified in the PCI
Cache Line Size Register. If a size other than 8 or 16 is specified, PCI 9080 performs write
transfers rather than Write and Invalidate transfers. Transfers must start and end at the
Cache Line Boundaries.
D14
DMA EOT (End of Transfer) Enable (Unused)
D15
DMA Stop Data Transfer Mode
A’0’ sends a BLAST to terminate DMA transfer
Note: This bit should always be set to ‘0’.
D16
DMA Clear Count Mode (Unused)
D17
DMA Channel 0 Interrupt Select
A ‘1’ routes the DMA Channel 0 interrupt to the PCI interrupt.
Note: This bit should always be set to ‘1’.
D31:18
Reserved
3.4.2
DMA
C
HANNEL
0
PCI
A
DDRESS
R
EGISTER
:
(PCI
0
X
84)
D31:0
PCI Address Register
3.4.3
DMA
C
HANNEL
0
L
OCAL
A
DDRESS
R
EGISTER
:
(PCI
0
X
88)
D31:0
Local Address Register
Note: Should be set to Local FIFO offset 0x18.
3.4.4
DMA
C
HANNEL
0
T
RANSFER
S
IZE
(B
YTES
)
R
EGISTER
:
(PCI
0
X
8C)
D22:0
DMA Transfer Size
D31:23
Reserved
3.4.5
DMA
C
HANNEL
0
D
ESCRIPTOR
P
OINTER
R
EGISTER
:
(PCI
0
X
90)
D0
Descriptor Location
A ‘1’ indicates PCI address space.
Note:
This bit should always be set to ‘1’ if Chained DMA enabled.
D1
End of Chain
D2
Interrupt after Terminal Count
D3
Direction of transfer
A ‘1’ indicates transfers from local bus to PCI bus (Read Receive FIFO)
A ‘0’ indicates transfers from local bus to PCI bus (Write Transmit FIFO)
D31:4
Next Descriptor Address