Product manual

Barracuda ATA V Product Manual, Rev. E 33
4.1.3 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 Sector Count register value).
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
05
H
Enable advanced power management.
42
H
Auto acoustic management (based on section count register value).
FE
H
Performance seek
80
H
Quiet acoustic seek
55
H
Disable read look-ahead (read cache) feature.
82
H
Disable write cache.