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SATA Interface
4.3.2
Set Features command
This command controls the implementation of various features that the drive supports. When the drive receives this
command, it sets BSY, checks the contents of the Features register, clears BSY and generates an interrupt. If the value in the
register does not represent a feature that the drive supports, the command is aborted. Power-on default has the read look-
ahead and write caching features enabled. The acceptable values for the Features register are defined as follows:
Table 8
Set Features command
02H
Enable write cache (default)
03H
Set transfer mode (based on value in Sector Count register)
Sector Count register values:
00H
Set PIO mode to default (PIO mode 2)
01H
Set PIO mode to default and disable IORDY (PIO mode 2)
08H
PIO mode 0
09H
PIO mode 1
0AH PIO mode 2
0BH
PIO mode 3
0CH PIO mode 4 (default)
20H
Multiword DMA mode 0
21H
Multiword DMA mode 1
22H
Multiword DMA mode 2
40H
Ultra DMA mode 0
41H
Ultra DMA mode 1
42H
Ultra DMA mode 2
43H
Ultra DMA mode 3
44H
Ultra DMA mode 4
45H
Ultra DMA mode 5
46H
Ultra DMA mode 6
06H
Enable the PUIS feature set
07H
PUIS feature set device spin-up
10H
Enable use of SATA features
55H
Disable read look-ahead (read cache) feature
82H
Disable write cache
86H
Disable the PUIS feature set
90H
Disable use of SATA features
AAH
Enable read look-ahead (read cache) feature (default)
F1H
Report full capacity available
Note
At power-on, or after a hardware or software reset, the
default values of the features are as indicated above.
Seagate SkyHawk Product Manual, Rev. A
30