Seagate ST34321A Product Manual - Page 37

Set Features command

Get Seagate ST34321A PDF manuals and user guides View all Seagate ST34321A manuals
Add to My Manuals
Save this manual to your list of manuals

Page 37 highlights

Medalist 8641, 6531, 4321, 3221 and 2110, Rev. B 29 3.2.3 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: 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 (default) 0BH PIO mode 3 0CH PIO mode 4 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 55H Disable read look-ahead (read cache) feature 82H Disable write cache AAH Enable read look-ahead (read cache) feature (default) F1H Report full capacity available At power-on, or after a hardware reset, the default values of the features are as indicated above. A software reset also changes the features to the default values.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
3.2.3
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:
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
(default)
0B
H
PIO mode 3
0C
H
PIO mode 4
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
55
H
Disable read look-ahead (read cache) feature
82
H
Disable write cache
AA
H
Enable read look-ahead (read cache) feature
(default)
F1
H
Report full capacity available
At power-on, or after a hardware reset, the default values of the features
are as indicated above. A software reset also changes the features to
the default values.
Medalist 8641, 6531, 4321, 3221 and 2110, Rev. B
29