LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 47

• Manufacturer Part Number: LSI53C875
• Description: PCI to Ultra SCSI I/O Processor
• Manufacturer: LSI Logic

2.5.9.2 Terminator Networks
The terminator networks provide the biasing needed to pull signals to an
inactive voltage level, and to match the impedance seen at the end of
the cable with the characteristic impedance of the cable. Terminators
must be installed at the extreme ends of the SCSI chain, and only at the
ends. No system should ever have more or less than two terminators
installed and active. SCSI host adapters should provide a means of
accommodating terminators. There should be a means of disabling
termination.
SE cables can use a 220
(Term Power) line and a 330
high-performance nature of the LSI53C875, regulated (or active)
termination is recommended.
terminator. For additional information, refer to the SCSI-2 Specification.
TolerANT technology active negation can be used with either termination
network.
PCI Cache Mode
Note:
If the LSI53C875 is to be used in a design with only an
8-bit SCSI bus, all 16 data lines still must be terminated or
pulled high. Active termination is required for Ultra SCSI
synchronous transfers.
pull-up to the terminator power supply
Figure 2.4
pull-down to ground. Because of the
shows a Unitrode active
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