Fujitsu MJA2080BH, Product/Maintenance Manual, Page: 91 / 320

5.2 Logical Interface
C141-E293 5-17
5.2.3.5 DMA Setup - Device to Host or Host to Device (Bidirectional)
The DMA Setup - Device to Host or Host to Device FIS has the following layout:
3
1 3
0 2
9 2
8 2
7 2
6 2
5 2
4 2
3 2
2 2
1 2
0 1
9 1
8 1
7 1
6 1
5 1
4 1
3 1
2 1
1 1
0 9 8 7 6 5 4 3 2 1 0
Reserved (0) Reserved (0) A I D Reserved (0) FIS Type (41h)
0
0 TAG
1
0
2
Reserved (0)
3
DMA Buffer Offset
4
DMA Transfer Count
5
Reserved (0)
6
Figure 5.7 DMA Setup - Device to Host or Host to Device FIS layout
The DMA Setup - Device to Host or Host to Device FIS communicates the start of
a first-party DMA access to the host system. This FIS is used to request the host
system or device to set up the DMA controller before the start of a DMA data
transfer.
A - Auto Active bit. If this bit is cleared ("0" is set for the bit), it indicates that a
DMA Active FIS transfer is required before a Data FIS transfer.
D - Direction bit. If this bit is set ("1" is set for the bit), it indicates that the data
transfer direction is from the device to the host system.