Scsi Interface - HP X Class 500/550MHz Reference Manual

Interface Boards and Mass-Storage
SCSI/LAN Combination Board

SCSI Interface

The Symbios Logic SYM5C875JE PCI-SCSI I/O Processor chip connects the SCSI bus
directly and generates timing and protocol in compliance with the SCSI standard. The
following hardware functional diagram shows the SCSI part of the SCSI/LAN Combo
board.
Figure 3-5. SCSI Part of the SCSI/LAN Combo Board
External connector (16
Ext.
To ExtStart Connector
SCSI
LED connector
(not loaded)
The SCSI interface operates as a 16-bit, synchronous or asynchronous, single-ended bus,
and supports Ultra SCSI protocols and 16-bit arbitration. The interface is made through
two (and only two) of the following connectors:
Table 3-3. SCSI Interface Connectors
Connector
J3 Internal Wide SCSI connector.
Non-shielded 68-pin high density
right-angle receptacle.
J7 External wide SCSI connector.
Shielded 68-pin high density
right-angle receptacle.
J9 Internal narrow SCSI connector.
Non-shielded 50-pin low-density
straight receptacle.
76
Drivers
Osc.
40 MHz
EEPRO
Clock
M
Data
2 KB
Description
5V
Fuse 3A
SCSI
Bus
Internal connector
SCSI Controller
SYM53C875JE
PCI Bus
Location
Internal connector at
the end of the board.
Protrudes through the
rear panel bracket.
Located between the
Symbios Logic chip
and Internal side
SCSI connector.
Internal connector (16
(8 bits)
12V
VPP Transla-
tor
Flash Memory
28F010
128 KB
Comments
Connectors J3 and J9
cannot be connected
to any devices at the
same time. If they are,
this results in a badly
"terminated" SCSI
bus. Refer to the
previous page for
further details.
Chapter 3