User's Manual

5.2 Logical Interface
C141-E262 5-15
5.2.3.2 Register - Host to Device
The Register - 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
Features Command C R R Reserved (0) FIS Type (27h)
0
Device LBA High LBA Mid LBA Low
1
Features (exp) LBA High (exp) LBA Mid (exp) LBA Low (exp)
2
Control Reserved (0) Sector Count (exp) Sector Count
3
Reserved (0) Reserved (0) Reserved (0) Reserved (0)
4
Figure 5.4 Register - Host to Device FIS layout
The host system uses the Register - Host to Device FIS when information in the
Register Block is transferred from the host system to the device. This is the
mechanism for issuing the ATA command from the host system to the device.
C - To update the Command field, "1" would be set in this field; and to update
the Device Control field, "0" would be set in the field.
If both C = 1 and SRST = 1 are set, operation is not guaranteed.