Hitachi HDS721075CLA632 Manuel D’Utilisation
Hitachi hard disk drive specifications
50
8.7 Drive Address Register
Drive Address Register
7
6
5
4
3
2
1
0
HIZ
-WTG
-H3
-H2
-H1
-H0
-DS1
-DS0
Table 29 Drive Address Register
This register contains the inverted drive select and head select addresses of the currently selected drive.
Bit Definitions
HIZ
High Impedance. This bit is not driven and will always be in a high impedance state.
-WTG
-Write Gate. This bit is 0 when writing to the disk device is in progress.
-H3,-H2,-H1,-H0
-Head Select. These four bits are the one's complement of the binary coded address
of the currently selected head. -H0 is the least significant.
of the currently selected head. -H0 is the least significant.
-DS1
-Drive Select 1. Drive select bit for device 1, active low. DS1=0 when device 1 (slave)
is selected and active.
is selected and active.
-DS0
-Drive Select 0. Drive Select bit for device 0, active low. DS0=0 when device 0
(master) is selected and active.
(master) is selected and active.
8.8 Device/Head Register
Device/Head Register
7
6
5
4
3
2
1
0
1
L
1
DRV
HS3
HS2
HS1
HS0
Table 30 Device/Head Register
This register contains the device and head numbers.
Bit Definitions
L
Binary encoded address mode select. When L=0, addressing is by CHS mode. When
L=1, addressing is by LBA mode.
L=1, addressing is by LBA mode.
DRV
Device. This product ignores this bit.
HS3,HS2,HS1,HS0
Head Select. These four bits indicate binary encoded address of the head. HS0 is the
least significant bit. At command completion, these bits are updated to reflect the
currently selected head.
The head number may be from zero to the number of heads minus one.
In LBA mode, HS3 through HS0 contain bits 24-27 of the LBA. At command
completion, these bits are updated to reflect the current LBA bits 24-27.
least significant bit. At command completion, these bits are updated to reflect the
currently selected head.
The head number may be from zero to the number of heads minus one.
In LBA mode, HS3 through HS0 contain bits 24-27 of the LBA. At command
completion, these bits are updated to reflect the current LBA bits 24-27.