8-34 SCSI and I/O
Table 8-15 J2 Option Connector
REMOTE
Open Drive will operate as a Stand Alone Device. Jumpers should be used to select SCSI ID.
Shorted Drive will operate as a Remote Device. The SCSI ID is set by applying remote logic (low true) to
the Unit Select pin sets.
AUTO SPIN-UP
Open Disabled, drive will not spin up until initiator sends Start Unit Command. (With auto spin-up dis-
abled, the drive will return "not ready" to all commands except REQUEST SENSE, INQUIRY,
RESERVE, RELEASE, and START UNIT until the drive is ready for access.)
Shorted Enabled, the drive will spin-up automatically at power on.
Table 8-16 J3 Option Connector Pin Definitions
Pinset Upper Pin Lower Pin
1 SCSI Unit Select 0: input, negative true Open collector output: pulled high if Remote pinset is
shorted; pulled low if Remote pinset is open
2 SCSI Unit Select 1: input, negative true Open collector output: pulled high if Remote pinset is
shorted; pulled low if Remote pinset is open
3 SCSI Unit Select 2: input negative true Sync spindle output if Remote is shorted; pulled low if
Remote pinset is open
4 SCSI Unit Select 3: input negative true Activity LED open collector output for external drive
activity LED; pulled low during initialization for
address selection
5 Reserved, must be open Ground
6 +5Vdc output: may be used to power
external LED (there is a 261 Ohm current
limiting resistor in series with this pin)
Write Protect:
Open: the drive looks at Mode Page Header and
responds accordingly; default = NOT write protected.
Shorted: drive is forced into the Write protect mode.
Table 8-17 J3 U/Sel SCSI Address Settings
SCSI Address U/Sel 3 U/Sel 2 U/Sel 1 U/Sel 0
0OOOO
1OOOS
2OOSO
3OOSS
4OSOO
5OSOS
6 OSSO
7OSSS
8SOOO
9SOOS
10 S O S O
11 S O S S
12 S S O O
13 S S O S
14 SSS0
15 SSSS
O = Open (or false), S = Shorted (or true)
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