IBM IC25N020ATDA04 - Travelstar 20 GB Hard Drive Specifications page 63

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, 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 procedure 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 connector is at Position-3.
When CSEL is at ground or is at a low level, the HDD works as a Master. If CSEL is open or is at a
logical high level, the HDD works as a Slave.
The signal level of CSEL to one HDD should be different from the signal level to another HDD on the
same AT interface cable to avoid master-master or slave-slave configurations.
KEY
Pin position 20 has no connection pin. Closing the respective position of the cable connector in order
to avoid incorrect insertion is recommended.
IORDY
This signal indicated 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 HDD needs one or more additional WAIT
cycles to extend the PIO cycle. This line can be connected to the host IORDY signal in order to insert
one or more WAIT states into the host PIO cycle. This signal is an Open-Drain output with 24 mA
sink capability.
5V Power
There are two input pins for the +5 V power supply. One is the "+5 V Logic" input pin and the second
is the "+5 V Motor" input pin. These two input pins are tied together within the drive.
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 15 K
–50% to +100%.
DMARQ
This signal is used for DMA data transfers between the host and drive. It is asserted by the drive
when it is ready to transfer data to or from the host. The direction of data transfer is controlled by
–HIOR and –HIOW 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 K
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 effect a pause in Ultra DMA data in transfers.
Travelstar 48GH, 30GN & 15GN hard disk drive specifications
resistor with a resistor tolerance value of
49
resistor.