Hitachi HTS421212H9AT00 - Travelstar 120 GB Hard Drive Specifications page 56

DASP-
This is a time-multiplexed signal which indicates that a drive is active or that device 1 is present. This signal is
driven by an Open-Drain driver and internally pulled up to 5.0 volts through a 10 k. resistor. During a Power-
On initialization or after RESET- is negated, DASP- shall be asserted by device 1 within 400 ms to indicate
that device 1 is present. Device 0 shall allow up to 450 ms for device 1 to assert DASP-. If device 1 is not
present, device 0 may assert DASP- to drive an LED indicator on a host. The DASP- signal shall be negated fol-
lowing acceptance of the first valid command by device 1. Anytime after negation of DASP-, either drive may
assert DASP- to indicate that a drive is active.
Caution
The host shall not drive DASP-. If the host connects to DASP- for any purpose, the host shall ensure that the
signal level detected on the interface for DASP- shall maintain VoH and VoL compatibility, given the IoH and
IoL requirements of the DASP- device drivers.
Caution
When DASP- is negated, the line is in a high impedance state. The signal level may look less than 5.0V even
though the line is pulled up to 5.0V through a resistor."
PDIAG-
This signal shall be asserted by device 1 to indicate to device 0 that it has completed the diagnostics. This line is
pulled up to 3.3 volts in the drive through a 10 kΩ resistor.
Following a Power On Reset, software reset, or RESET-, drive 1 shall negate PDIAG- within 1 ms (to indicate
to device 0 that it is busy). Drive 1 shall then assert PDIAG- within 30 seconds to indicate that it is no longer
busy and is able to provide status.
Following the receipt of a valid Execute Drive Diagnostics command, device 1 shall negate PDIAG- within 1
ms to indicate to device 0 that it is busy and has not yet passed its drive diagnostics. If device 1 is present then
device 0 shall wait up to 6 seconds from the receipt of a valid Execute Drive Diagnostics command for drive 1
to assert PDIAG-. Device 1 should clear BSY before asserting PDIAG-, as PDIAG- is used to indicate that
device 1 has passed its diagnostics and is ready to post status. If DASP- was not asserted by device 1 during
reset initialization, device 0 shall post its own status immediately after it completes diagnostics and clears the
device 1 Status register to 00h. Device 0 may be unable to accept commands until it has finished its reset proce-
dure and is ready (DRDY=1).
CSEL (Cable Select)
This signal is monitored to determine the drive address (master or slave) when the jumper on the interface con-
nector is at Position-3.
When CSEL is at ground or is at a low level, the drive works as a Master. If CSEL is open or is at a logical high
level, the drive works as a Slave.
The signal level of CSEL to one drive should be different from the signal level to another drive on the same AT
interface cable to avoid master-master or slave-slave configurations.
KEY
Pin position 20 has no connection pin. It is recommended to close the respective position of the cable connector
in order to avoid incorrect insertion.
IORDY
This signal is an indication to the host that the drive is ready to complete the current I/O cycle. This line is
driven low at the falling edge of DIOR- or DIOW-when the drive needs some additional WAIT cycle(s) to
Travelstar 4K120 Hard Disk Drive Specification
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