Seagate Exos X20 SATA Product Manual, Rev. B
50
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Serial ATA (SATA) interface
5.3.4
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:
NOTE
At power-on, or after a hardware or software reset, the default values of the
features are as indicated above.
Table 14 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:
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
