Seagate ST32000641AS ユーザーズマニュアル
Barracuda XT Series SATA Product Manual, Rev. C
27
4.3.2
Set Features command
This command controls the implementation of various features that the drive supports. When the drive receives this com-
mand, 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:
mand, 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:
Note.
At power-on, or after a hardware or software reset, the default values of the features are as indicated above.
Table 7:
Set Features command values
02
H
Enable write cache (default).
03
H
Set transfer mode (based on value in Sector Count register).
Sector Count register values:
Sector Count register values:
00
H
Set PIO mode to default (PIO mode 2).
01
H
Set PIO mode to default and disable IORDY (PIO mode 2).
08
H
PIO mode 0
09
H
PIO mode 1
0A
H
PIO mode 2
0B
H
PIO mode 3
0C
H
PIO mode 4 (default)
20
H
Multiword DMA mode 0
21
H
Multiword DMA mode 1
22
H
Multiword DMA mode 2
40
H
Ultra DMA mode 0
41
H
Ultra DMA mode 1
42
H
Ultra DMA mode 2
43
H
Ultra DMA mode 3
44
H
Ultra DMA mode 4
45
H
Ultra DMA mode 5
46
H
Ultra DMA mode 6
10
H
Enable use of SATA features
55
H
Disable read look-ahead (read cache) feature.
82
H
Disable write cache
90
H
Disable use of SATA features
AA
H
Enable read look-ahead (read cache) feature (default).
F1
H
Report full capacity available