User manual

Hitachi hard disk drive specifications
192
11.37.2 Set Transfer mode
When Feature register is 03h (=Set Transfer mode), the Sector Count Register specifies the transfer mechanism.
The upper 5 bits define the type of transfer and the low order 3 bits encode the mode value.
PIO Default Transfer Mode
00000
000
PIO Default Transfer Mode
Disable IORDY
00000
001
PIO Flow Control Transfer Mode x
00001
nnn
(nnn=000,001,010,011,100)
Multiword DMA mode x
00100
nnn
(nnn=000,001,010)
Ultra DMA mode x
01000
nnn
(nnn=000,001,010,011,100,101,11
0)
11.37.3 Write Cache
If the number of auto reassigned sector reaches the device‟s reassignment capacity, the write cache function
will be automatically disabled. Although the device still accepts the Set Features command with Feature register
= 02h without error, but the write cache function will remains disabled. For current write cache function status,
please refer to Identify Device Information (word 85 or 129) by Identify Device command.
11.37.4 Serial ATA Feature
When the Feature register is set to 10h or 90h, the value set to the Sector Count register specifies the specific
Serial ATA feature to enable or disable.
Sector Count Value
Description
01h
Non-zero buffer offset in DMA Setup FIS
02h
DMA Setup FIS Auto-Activate optimization
03h
Device-initiated interface power state transitions
04h
Guaranteed In-Order Data Delivery
06h
Software Settings Preservation
11.37.5 Advanced Power Management
When the value in the Feature register is 05h (=Enable Advanced Power Management), the Sector Count
Register specifies the Advanced Power Management level.
FFh ---
Aborted
C0 – Feh ---
The deepest Power Saving mode is Normal Idle mode
(the same as Disable Advanced Power Management)
80 – BFh ---
The deepest Power Saving mode is Low power Idle mode
01 – 7Fh ---
The deepest Power Saving mode is Low RPM standby mode
00h ---
Aborted
The idle time to Low power idle mode and Low RPM standby mode vary according to the value in Sector Count
register as follows:
When Low power idle mode is the deepest Power Saving mode,
Y
1
=(x-80h) * 5+120 [sec] (120<= Y
1
<=435)
Y
2
=N/A(the device does not go to Low RPM standby mode)
When Low RPM standby mode is the deepest Power Saving mode and the value in Sector Count register is
between 40h and 7Fh,
120<=Y
1
<=435 [sec] (default: 120 [sec])