Scsi Id Selection - Sun Microsystems Ultra 80 Service Manual

addition to the SCSI signals, the 80-conductor cable carries diskette drive and system
LED signals to the SCSI backplane card. The IDC receptacle mates with a right-angle
plug that is mounted on the motherboard.
The 80-conductor cable attaches on the other end to the SCSI backplane card with
another IDC connector. The SCSI backplane card incorporates two SCA-2 connectors
for mounting the hard drives, a four-circuit power connector to supply 5 VDC and
12 VDC power to the hard drives, a 34-pin diskette drive signal connector, and a
green, right-angle LED.
A 68-conductor cable exits the SCSI backplane card, carrying 27 SCSI signals and the
Termpower to the internal CD-ROM drive (or tape drive). The SCSI backplane card
houses the CD-ROM drive connector and three SCSI bus terminators. The
Termpower is routed through the SCSI subassembly to connect to the terminators on
the SCSI backplane card in support of the multi-host configuration. The following
figure shows the functionality of the internal SCSI subassembly.
68-pin external SCSI connector
SCSI bus
FIGURE C-10
C.1.13.5

SCSI ID Selection

The motherboard host adapter is assigned the SCSI identification of 7 for both ports.
The two internal drives attached to the SCA-2 connectors have a SCSI identification
of 0 and 1, while the CD-ROM has an identification of 6.
-32 Sun Ultra 80 Service Manual • March 2000
Motherboard
SCSI
controller
Board-mounted right-angle IDC plug
SCSI Subassembly Functional Block Diagram
68-pin cable
IDC connector
CD-ROM drive connector
SCA-2 connector
SCSI bus terminator (3)
Drive
power
Diskette
signal
80-conductor cable
Test edge connector
IDC receptacle connector
IDC connector
SCA-2
connector (2)
IDC connector