Product manual

36 Product Manual - Hawk 2 Family (Wide bus) SCSI-2 (Volume 1), Rev. A
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Notes for Figure 10.1-1a, 10.1-1b and 10.1-1c:
[1] Notes explaining the functions of the various jumpers on jumper header connectors J2, J1-auxiliary and
J6 are given below in left to right order of jumper position. The term “default” means as standard OEM
units are configured when shipped from factory. “Off” means no jumper is installed; “On” means a jumper
is installed. “Off” or “On” underlined is factory default condition.
[2] The PCB on "WC" models does not have connector J1-auxiliary, but has a single 80 pin combined SCSI
I/O and DC power connector instead of the pictured 68 pin SCSI I/O, J1-auxiliary and 4 pin DC power
connectors. Included among the 80 pins are the SCSI ID, Motor Start and Delayed Motor Start select
functions, and the synchronous spindle master sync signal (REFIND+) and the remote LED signals. Do
not use J2 and J6 for these five functions if the host uses the ones included in the 80 pin connector. See
Table 11.6.3-1c for a list of pin numbers vs. signals for the 80 pin connector.
[3] Either jumper plugs in one of the patterns shown or external circuitry can be used to establish Drive ID.
The drive uses headers J6 or J1-auxiliary for drive ID determination only during a 250 ms initialization
period following power-on or after a drive reset. During this initialization period, the drive control logic
connects pins 2, 4, 6 and 8 to ground and checks the logic state of pins 1, 3, 5 and 7. A ground on a pin
1, 3, 5, 7 indicates an asserted low state, while an open circuit, high impedance or +5 V indicates a
negated high state. The drive user can install jumper plugs to connect pins 2, 4, 6 and 8 to pins 1, 3, 5 and
7, respectively, in the desired ID pattern. See figures 10.1-1a and 10.1-1b. The drive only connects
ground to pins 2, 4, 6 and 8 during the 250 ms initialization period. The user may install a cable on J6 or
J1-auxiliary in order to connect the drive ID pattern to pins 1, 3, 5 and 7 through some external switching
circuit. The drive ID should be applied for at least the 250 ms period. During the remaining operational
time of the drive, the drive does not poll pins 1, 3, 5 and 7 for drive ID, unless a reset occurs. See Note [4]
for information on the use of pins 2, 4, 6 and 8 during non-initialization periods.
[4] During non-initialization periods when the drive does not connect ground to pins 2, 4, 6 and 8, these pins
can be used for non-drive ID functions. Therefore, instead of using jumper plugs on J1-auxiliary to estab-
lish drive ID, a cable can be connected to either J6 or J1-auxiliary to connect the drive activity (busy) LED
as shown and make parallel connections of pins 1, 3, 5 and 7 to external drive ID switching or jumpering
circuits. If connected as shown, pin 8 lights the drive busy LED when the drive connects ground to that
pin. Connection can be made to pin 6 to conduct the synchronized spindle reference signal, REFIND+ to
the host and to other Seagate disk drives. Spindle synchronization typically works effectively only if all
drives connected through pin 6 are identical in make and model. During the 250 ms initialization period
the LED lights and the REFIND+ signal goes to 0 V.
J6 can be used to establish drive ID using jumpers (or remote ID selector) and a cable can be plugged
simultaneously to J1-auxiliary to connect to the drive activity (busy) LED and the synchronized spindle
signal SSP. The vice-versa arrangement is possible also. Two separate drive ID determining locations
should not be used, however.