Signal Descriptions; Table 17. Special Signal Definitions For Ultra Dma - Hitachi HDS725050KLA360 Specifications

6.3 Signal descriptions

Table 17: Special signal definitions for Ultra DMA
Write Operation
Read Operation
DD00–DD15
A 16-bit bi-directional data bus between the host and the drive. The lower 8 lines, DD00-07, are used for Regis-
ter and ECC access. All 16 lines, DD00–15, are used for data transfer. These are 3-state lines with 24 mA cur-
rent sink capability.
DA00–DA02
These are addresses used to select the individual register in the drive.
CS0-
The chip select signal generated from the Host address bus. When active, one of the Command Block Registers
[Data, Error (Features when written), Sector Count, Sector Number, Cylinder Low, Cylinder High, Drive/Head
and Status (Command when written) register] can be selected. (See Table 41: "I/O address map" on page 43.)
CS1-
The chip select signal generated from the Host address bus. When active, one of the Control Block Registers
[Alternate Status (Device Control when written) and Drive Address register] can be selected. (See Table 41: "I/
O address map" on page 43.)
RESET-
This line is used to reset the drive. It shall be kept at a Low logic state during power up and kept High thereafter.
DIOW-
The rising edge of this signal holds data from the data bus to a register or data register of the drive.
DIOR-
When this signal is low, it enables data from a register or data register of the drive onto the data bus. The data on
the bus shall be latched on the rising edge of DIOR-
INTRQ
The interrupt is enabled only when the drive is selected and the host activates the IEN- bit in the Device Control
Register. Otherwise, this signal is in high impedance state regardless of the state of the IRQ bit. The interrupt is
set when the IRQ bit is set by the drive CPU. The IRQ is reset to zero by a host read of the status register or a
write to the Command Register. This signal is a 3-state line with 24mA of sink capability.
Special Definition
(for Ultra DMA)
DDMARDY-
HSTROBE
STOP
HDMARDY-
DSTROBE
STOP
Deskstar 7K500 and Deskstar E7K500 Hard Disk Drive Specification
Conventional
Definition
IORDY
DIOR-
DIOW-
DIOR-
IORDY
DIOW-
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