Registers; Figure 53. Register Set - IBM IC25N020ATDA04 - Travelstar 20 GB Hard Drive Specifications

10.0 Registers

Addresses
CS0- CS1- DA2
N N x
N A 0
N A 1
N A 1
A N 0
A N 0
A N 0
A N 0
A N 0
A N 1
A N 1
A N 1
A N 1
A N 1
A N 1
A N 1
A A x
Logic conventions: A = signal asserted
N = signal not asserted
x = can be either

Figure 53. Register Set

Communication to or from the device is through an I/O Register that routes the input or output data to or
from the registers addressed by the signals from the host (CS0-, CS1-, DA2, DA1, DA0, DIOR- and
DIOW-).
The Command Block Registers are used for sending commands to the device or posting status from the
device.
The Control Block Registers are used for device control and to post alternate status.
DA1 DA0
Data bus high imped
x x
(*1)
x x Data bus high imped
0 x Data bus high imped
1 0 Alternate Status
0 0 Data
0 1 Error Register
1 0 Sector Count
1 1 Sector Number
1 1 LBA bits 0-7 (*2)
0 0 Cylinder Low
0 0 LBA bits 8-15 (*2)
0 1 Cylinder High
0 1 LBA bits 16-23 (*2)
1 0 Device/Head.
1 0 LBA bits 24-27 (*2)
1 1 Status
x x Invalid address
Travelstar 48GH, 30GN & 15GN hard disk drive specifications
Functions
READ (DIOR-)
Control block registers
Command block registers
*1 imped = impedance
*2 = Mapping of registers in LBA mode
71
WRITE (DIOW-))
Not used
Not used
Not used
Device Control
Data
Features
Sector Count
Sector Number
LBA bits 0-7 (*2)
Cylinder Low
LBA bits 8-15 (*2)
Cylinder High
LBA bits 16-23 (*2)
Device/Head
LBA bits 24-27 (*2)
Command
Invalid address