Programming 47
Table 3-45 DMA Channel 0 Transfer Size (Bytes) Register
DMASIZ0: BAR0/1 Offset $8C
Bit
Description
Read
Write
Value after
PCI Reset
22:0
DMA Transfer Size (Bytes).
Indicates the number of bytes to transfer
during a DMA operation.
Yes
Yes
$0
31:23
Reserved
Yes
No
$0
Table 3-46 DMA Channel 0 Descriptor Pointer Register
DMADPR0: BAR0/1 Offset $90
Bit
Description
Read
Write
Value after
PCI Reset
0
DMA Channel 0 Descriptor Location.
A one (1) indicates PCI Address space.
Yes
No
1
2:1
Reserved
N/A
N/A
0
3
Direction of Transfer.
Writing a one (1) indicates transfer from the RFM to the PCI bus.
Writing a zero (0) indicates transfer from the PCI bus to the RFM.
Yes
Yes
0
31:4
Channel 0 First Descriptor Address.
This field holds bits [31:4] of the first DMA descriptor address. The first
descriptor address must be aligned on a 16-byte boundary (i.e.,
address bits [3:0] are considered to be $0).
Yes
Yes
$0
Table 3-47 DMA Channel 0 Command/Status Register
DMACSR0: BAR0/1 Offset $A8
Bit
Description
Read
Write
Value after
PCI Reset
0
Channel 0 Enable
.
Writing a one (1) enables channel to transfer data.
Writing a zero (0) disables the channel from starting a DMA
transfer.
Yes
Yes
0
1
Channel 0 Start
.
Writing a one (1) causes channel to start transferring data if the
channel is enabled.
No
Yes/Set
0
2
Reserved
No
No
0
3
Channel 0 Clear Interrupt
.
Writing a one (1) clears Channel 0 interrupts.
No
Yes/Clr
0
4
Channel 0 Inactive
.
Reading a one (1) indicates a channel transfer is complete.
Reading a zero (0) indicates a channel transfer is not complete.
Yes
No
1
7:5
Reserved
Yes
No
000