LSI LSI53C1030, Technical Manual

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Ultra320 SCSI Functional Description 2-23
Version 2.1 Copyright © 2001, 2002, 2003 by LSI Logic Corporation. All rights reserved.
problems. The margined check verifies that the physical parameters
have a reasonable operating margin. Use SureLINK Domain Validation
only during the diagnostic system checks and not during normal system
operation. If transmission errors occur during any of these checks, the
system can reduce the transmission rate on a per-target basis to ensure
robust system operation.
2.4.2 SCSI Bus Interface
This section describes the SCSI bus modes that the LSI53C1030
supports and the SCSI bus termination methods necessary to operate a
high speed SCSI bus.
2.4.2.1 SCSI Bus Modes
The LSI53C1030 supports SE and LVD transfers. To increase device
connectivity and SCSI cable length, the LSI53C1030 features LVDlink
technology, which is the LSI Logic implementation of LVD SCSI. LVDlink
transceivers provide the inherent reliability of differential SCSI and a
long-term migration path for faster SCSI transfer rates.
The A_DIFFSENS or B_DIFFSENS signals detect the different input
voltages for HVD, LVD, and SE. The LSI53C1030 drivers are tolerant of
HVD signal strengths, but do not support the HVD bus mode. The
LSI53C1030 SCSI device 3-states its SCSI drivers when it detects an
HVD signal level.
2.4.2.2 SCSI Termination
The terminator networks pull signals to an inactive voltage level and
match the impedance seen at the end of the cable to the characteristic
impedance of the cable. Install terminators at the extreme ends of the
SCSI chain, and only at the ends; all SCSI buses must have exactly two
terminators.
Note: If using the LSI53C1030 in a design with an 8-bit SCSI bus,
designers must terminate all 16 data lines.