Avago Technologies LSI53C120 - Manual (Page 9)

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Copyright © 2001 by LSI Logic Corporation. All rights reserved.
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LSI20101/LSI20102
SCSI Bus Boards
1 Product Description
This document describes the LSI20101/LSI20102 family of SCSI boards
based on the LSI53C120 SCSI Bus Expander chip. The LSI20101
Extender and the LSI20102 Converter are wide (16-bit) SCSI bus
boards. The LSI20101 board connects a Single-Ended (SE) SCSI bus
segment to another SE bus segment. The LSI20102 board connects a
SE SCSI bus segment to a differential SCSI bus segment. These boards
provide electrical isolation between two SCSI bus segments, allowing for
increased device connectivity and greater cable distances. The bus
segments comprise one logical SCSI bus. The board attaches directly to
the SCSI bus; target and initiator devices can be located on either the A
or the B bus segments. Supporting SCSI-1, SCSI-2, and SCSI-3
standards, the boards work with any LSI Logic SCSI product, as well as
any other industry-standard SCSI controllers and devices up to Wide
Ultra SCSI with transfer rates of 40 Mbytes/s.
The heart of the LSI20101 and LSI20102 boards is the LSI53C120 SCSI
Bus Expander chip. The LSI53C120 chip checks SCSI signal tolerances
as signals are received and, if necessary, realigns them to the SCSI
specification. The LSI53C120 chip supports retiming logic, precision
delay control, state machine control, and differential control for the SCSI
signals. The additional circuitry on the LSI20101/2 boards provide
electrical isolation, termination, and buffering of the signals.
Section 1 of
this document describes the common characteristics of both boards.
Sections
2 through 5 describe the unique characteristics of each board.