Seagate ST9250315AS ユーザーズマニュアル

M

OMENTUS 

5400.6 SATA P

RODUCT 

M

ANUAL

, R

EV

. G

  32

  

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:

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

55

H

Disable read look-ahead (read cache) feature.

82

H

Disable write cache

AA

H

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

C1

H

Disable the Free Fall Protection feature (41

H

 above enables the Free Fall Protection feature)

F1

H

Report full capacity available