Hitachi HDS725050KLA360 Specifications page 42

DMACK-
This signal shall be used by the host in response to DMARQ to either acknowledge that data has been accepted,
or that data is available.
This signal is internally pulled up to 5 Volt through a 15kΩ resistor with a resistor tolerance value of –50% to
+100%.
DMARQ
This signal is used for DMA data transfers between the host and drive. It shall be asserted by the drive when it
is ready to transfer data to or from the host. The direction of data transfer is controlled by DIOR- and DIOW-
signals. This signal is used in a handshake mode with DMACK-. This signal is a 3-state line with 24 mA sink
capability and internally pulled down to GND through a 10 kΩ resistor.
HDMARDY- (Ultra DMA)
This signal is used only for Ultra DMA data transfers between host and drive. The signal HDMARDY- is a flow
control signal for Ultra DMA data in bursts. This signal is held asserted by the host to indicate to the device that
the host is ready to receive Ultra DMA data in transfers. The host may negate HDMARDY- to pause an Ultra
DMA data in transfer.
HSTROBE (Ultra DMA)
This signal is used only for Ultra DMA data transfers between host and drive.
The signal HSTROBE is the data out strobe signal from the host for an Ultra DMA data out transfer. Both the
rising and falling edge of HSTROBE latch the data from DD (15:0) into the device. The host may stop toggling
HSTROBE to pause an Ultra DMA data out transfer.
STOP (Ultra DMA)
This signal is used only for Ultra DMA data transfers between host and drive.
The STOP signal shall be asserted by the host prior to initiation of an Ultra DMA burst. A STOP shall be
negated by the host before data is transferred in an Ultra DMA burst. Assertion of STOP by the host during or
after data transfer in an Ultra DMA mode signals the termination of the burst.
DDMARDY- (Ultra DMA)
This signal is used only for Ultra DMA data transfers between host and drive.
The signal DDMARDY- is a flow control signal for Ultra DMA data out bursts. This signal is held asserted by
the device to indicate to the host that the device is ready to receive Ultra DMA data out transfers. The device
may negate DDMARDY- to pause an Ultra DMA data out transfer.
DSTROBE (Ultra DMA)
This signal is used only for Ultra DMA data transfers between host and drive.
The signal DSTROBE is the data in strobe signal from the device for an Ultra DMA data in transfer. Both the
rising and the falling edge of DSTROBE latch the data from DD (15:0) into the host. The device may stop tog-
gling DSTROBE to pause an Ultra DMA data in transfer.
Device termination
The termination resistors on the device side are implemented on the drive side as follows:
• 33 Ω for DD0 through DD15, DMARQ, INTRQ
• 82 Ω for CS0-, CS1-, DA0, DA1, DA2, DIOR-, DIOW-, DMACK-
• 22 Ω for IORDY
Deskstar 7K500 and Deskstar E7K500 Hard Disk Drive Specification
28