Logical Interface; I/O Registers; Data Register; Error Register - Hitachi DK23DA-30F - 30 GB Hard Drive Specifications

6.3 Logical Interface

6.3.1 I/O Registers

Communication between the host system and the device is done through I/O registers. The Command
Block Registers are used for sending commands to the device or posting device status. The Control
Block Registers are used for controlling the device or posting device status. The registers are listed in
Table 6.3.
CS0-
0
0
0
0
0
0
0
0
1
0
0
1
1
'0' is low signal level. '1' is high signal level.

6.3.1.1 Data register

A 16-bit register to be used for transferring data blocks between the HDD's data buffer and the host.

6.3.1.2 Error register

This register stores device status when the last command has been completed or diagnostic codes
when a self-diagnostic process has been completed. The contents of this register are valid when the
error bit (ERR) is set in the Status Register. The contents of this register are diagnostic codes when
the device has just completed a self-diagnostic process requested when turning on the power or
resetting.
K6602705
Rev.3
08.20.01
Addresses
CS1- DA2 DA1
Command Block Registers
1 0 0
1 0 0
1 0 1
1 0 1
1 1 0
1 1 0
1 1 1
1 1 1
0 1 1
´ ´
0
´ ´
1
´
0 0
0 1 0
Table 6.3 Register List
DA0 READ(DIOR-)
0 Data
1 Error
0 Sector Count
1 Sector Number
0 Cyl Low
1 Cyl High
0 Device/Head
1 Status
Control Block Registers
0 Alt. Status
Invalid or Not Used
´
Invalid address
´
Data bus high impedance (not used)
´
Data bus high impedance (not used)
´
Data bus high impedance (not used)
- 31 -
Functions
WRITE(DIOW-)
Data
Features
Sector Count
Sector Number
Cyl Low
Cyl High
Device/Head
Command
Device Control