4. IDE Interface
23
Drive/Head Register
(1F6h, Read/Write - 8 bits)
The drive/head register, also called the SDH register, contains the drive ID number and
its head numbers. The host defines the contents of the drive/head register by executing
the Initialize Drive Parameters command. At the completion of each sector and at the
end of the command this register is updated to reflect the currently selected head.
Register bits are defined in the following figure "SDH Register".
7
6
5
4
3
2
1
0
Drive Select Number
(0=Master, 1=Slave)
Head Address (Binary)
HS2
HS1
HS0
HS3
DRV
1
0
RSVD
Reserved
LSB
MSB
SDH Register
DRV—Drive Select Number
Indicates which drive is currently selected. The primary (master) drive is indicated by
logical 0. The secondary (slave) drive in a two-drive system is indicated by logical 1.
HS3—Most Significant Head Address Bit
HS2—
HS1—
HS0—Least Significant Head Address Bit
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
