Drive/Head Register; Table 23: Drive/Head Register - Silicon Systems SiliconDrive SSD-D16G(I)-3600 Datasheet

ATA R
EGISTERS
D /H R
RIVE EAD
The Drive/Head register is used by the host and the device to select the type
of addressing (CHS or LBA), the drive letter, and either bits 3-0 of the head
number in CHS mode or logical block number bits 27-24 in LBA mode.
Operation
Read/Write
Default
Value
The Drive/Head register is used by the host to specify one of a pair of ATA
drives present in the platform.
Bit(s)
6
4
3-0
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3600D-04DSR
EGISTER

Table 23: Drive/Head Register

D D
7 6
1 LBA
1 0
Description
LBA. Selects between CHS (0) and LBA (1) addressing mode.
Drive Address (DRV). Indicates the drive number selected by the
host, either 0 or 1.
HS3 to 0. Indicates bits 3-0 of the head number in CHS addressing
mode or LBA bits 27-24 in LBA mode.
• CHS to LBA conversion: LBA = (C x HpC + H) x SpH + S -1
• LBA to CHS conversion:
C = LBA/(HpC x SpH)
H = (LBA/SpH) mod (HpC)
S = (LBA mod(SpH)) + 1
...where:
C is the cylinder number
H is the head number
S is the sector count
HpC is the head count per cylinder count
SpH is the sector count per head count (track)
S S
ILICON YSTEMS
All unauthorized use and/or reproduction is prohibited.
SSD-D
D D D
5 4
1 DRV HS3
LBA27
1 0 0
P
ROPRIETARY
P 22
AGE
(I)-3600 D
XXX ATA
D D
3 2 1
HS2 HS1
LBA26 LBA25
0 0
F
EBRUARY
S
HEET
D
0
HS0
LBA24
0
2, 2009