2 the scsi interface, The scsi interface – Avago Technologies LSI21040 User Manual
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Operational Environment
3-7
3.2.2 The SCSI Interface
The SCSI interface conforms to ANSI X 3T10.11/1142. The SCSI
interface operates as 16-bit, synchronous or asynchronous, SE or LVD,
and supports Ultra160 SCSI protocols. Arbitration is supported for 8-bit
(at lower SCSI speeds) and 16-bit. Active SE or LVD SCSI termination
is provided automatically. SCSI termination power is supplied by the
board.
Connectors J3 and J4 for Channel A and J2 and J5 for Channel B make
the SCSI interface. Refer to
on
to see an example
of this interface. J2 and J4 are 68-pin high density right angle connectors
for internal SCSI connections. J5 is a 50-pin low density vertical
connector. External connector J3 is a shielded 68-pin high density right
angle connector exposed in the back panel bracket.
LVD/SE dual mode, active termination is provided on the LSI21040 for
Channel A. SE SCSI termination is provided for Channel B. The
LSI21040 supplies SCSI bus TERMPWR through a blocking diode and
a self-resetting 1.5 A short circuit protection device. A 40 MHz oscillator
is installed on the LSI21040. This oscillator provides the clock frequency
necessary to support Ultra160 SCSI transfers of up to 160 Mbytes/s.
and
show the signal assignments for J2 and J5.
and
show the signal assignments for J4 and J3.