Seagate ST9100011FS ユーザーズマニュアル

34

Pulsar Product Manual, Rev. A

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 inter-
rupt. 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:

At power-on, or after a hardware or software reset, the default values of the features are as

 

indicated above. 

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

02

H

DMA Setup FIS Auto-Activate optimization

03

H

Device-initiated interface power state transitions

06

H

Software Settings Preservation

55

H

Disable read look-ahead (read cache) feature

66

H

Disable reverting to power-on defaults

82

H

Disable write cache

90

H

Disable use of SATA features

02

H

DMA Setup FIS Auto-Activate optimization

03

H

Device-initiated interface power state transitions

06

H

Software Settings Preservation

AA

H

Enable read look-ahead (read cache) feature (default).

CC

H

Enable reverting to power-on defaults