Avago Technologies LSI53C120 User Manual

TECHNICAL

MANUAL

LSI53C120
Ultra SCSI Bus Expander

August 2001

Version 1.0

®

DB14-000181-00

This document contains proprietary information of LSI Logic Corporation. The
information contained herein is not to be used by or disclosed to third parties
without the express written permission of an officer of LSI Logic Corporation.

LSI Logic products are not intended for use in life-support appliances, devices,
or systems. Use of any LSI Logic product in such applications without written
consent of the appropriate LSI Logic officer is prohibited.

Document DB14-000181-00, First Edition (August 2001)
This document describes LSI Logic Corporation’s LSI53C120 Ultra SCSI Bus
Expander and will remain the official reference source for all revisions/releases
of this product until rescinded by an update.

LSI Logic Corporation reserves the right to make changes to any products herein
at any time without notice. LSI Logic does not assume any responsibility or
liability arising out of the application or use of any product described herein,
except as expressly agreed to in writing by LSI Logic; nor does the purchase or
use of a product from LSI Logic convey a license under any patent rights,
copyrights, trademark rights, or any other of the intellectual property rights of LSI
Logic or third parties.

Copyright © 1996-2001 by LSI Logic Corporation. All rights reserved.
TRADEMARK ACKNOWLEDGMENT

The LSI Logic logo design and TolerANT are trademarks or registered
trademarks of LSI Logic Corporation. All other brand and product names may be
trademarks of their respective companies.

MH

To receive product literature, visit us at http://www.lsilogic.com.
For a current list of our distributors, sales offices, and design resource

centers, view our web page located at
http://www.lsilogic.com/contacts/na_salesoffices.html

ii

Audience

Preface

This book is the primary reference and technical manual for the
LSI53C120 Ultra SCSI Bus Expander. It contains a complete functional
description and complete physical and electrical specifications for the
LSI53C120 Ultra SCSI Bus Expander chip, which supports single-ended
to single-end SCSI bus expansion (Extender) or single-ended to
differential SCSI bus conversion (Converter).

This manual assumes some prior knowledge of current and proposed
SCSI standards. For background information, please contact:

ANSI

11 West 42nd Street
New York, NY 10036
[phone]
Ask for document number X3.131-1994 (SCSI-2) (SCSI-3)

Global Engineering Documents

15 Inverness Way East
Englewood, CO 80112
[phone] or [phone] (outside U.S.)
Ask for document number X3.131-1994 (SCSI-2) or X3.253 (SCSI-3
Parallel Interface)

ENDL Publications

14426 Black Walnut Court
Saratoga, CA 95070
[phone]
Document names: SCSI Bench Reference, SCSI Encyclopedia

Prentice Hall

Englewood Cliffs, NJ 07632

Preface iii

[phone]
Ask for document number ISBN 0-13-796855-8, SCSI: Understanding
the Small Computer System Interface

LSI Logic World Wide Web

http://www.lsilogic.com
(See EPI (Enhanced Parallel Interface) Specification for expander
configurations)

Revision Record

Revision Date Remarks

1.0 8/01 All product name changes from a SYM to an LSI prefix. Updated

Organization

This document has the following chapters and appendixes:

figure references throughout book. Updated wiring diagram in
Appendix A.

• Chapter 1, Introduction, provides general information about the

LSI53C120 Ultra SCSI Bus Expander.

• Chapter 2, Functional Description, provides information about the

interface signal descriptions.

• Chapter 3, Specifications, describes the LSI53C120 as a 128-pin

PQFP. It also provides minimum and maximum values for the
electrical characteristics of this expander/converter.

• Appendix A, Differential Wiring Diagram, illustrates the LSI53C120

wiring diagram for Ultra SCSI operation.

• Appendix B, Glossary, provides definitions for key terms used in this

manual.

Related Publication

LSI53C141 SCSI Bus Expander, Version 2.1, LSI Logic Corporation,
Order No. S14013.A

iv Preface

Conventions Used in This Manual

The word assert means to drive a signal true or active. The word
deassert means to drive a signal false or inactive. Signals that are active

LOW end in a slash mark (/).

Preface v

vi Preface

Contents

Chapter 1 Introduction

1.1 General Description 1-1

1.2 Features 1-3

1.3 Application Examples 1-4

1.3.1 Scalable Device Connectivity 1-4

1.3.2 SCSI Bus Electrical Isolation 1-6

Chapter 2 Functional Description

2.1 Interface Signal Descriptions 2-1

2.1.1 SCSI A-Side and B-Side Single-Ended
Control Blocks 2-2

2.1.2 Re-timing Logic 2-3

2.1.3 Precision Delay Control 2-3

2.1.4 State Machine Control 2-4

2.1.5 Differential Control 2-4

2.2 SCSI Signal Descriptions 2-4

2.2.1 Data and Parity 2-5

2.2.2 Busy (BSY) Control 2-6

2.2.3 Reset (RST) Control 2-7

2.2.4 Request (REQ)/Acknowledge (ACK) Control 2-7

2.2.5 Control/Data (C/D), Input/Output (I/O),
Message (MSG) and Attention (ATN) Controls 2-8

2.2.6 Differential Direction Controls 2-8

2.2.7 Differential Mode (DIFF_MODE/) 2-9

2.2.8 Differential Sense (DIFF_SENSE) 2-9

2.2.9 Control Signals 2-10

Contents vii

Chapter 3 Specifications

3.1 Signal Descriptions 3-1

3.1.1 LSI53C120 Pin Diagram 3-1

3.1.2 LSI53C120 Signal Grouping 3-3

3.1.3 SCSI A Interface Pins 3-4

3.1.4 SCSI B Single-ended Interface Pins 3-5

3.1.5 SCSI B Differential Interface Pins 3-6

3.1.6 Control Interface Pins 3-7

3.2 Electrical Characteristics 3-8

3.2.1 DC Characteristics 3-8

3.2.2 TolerANT Technology Electrical Characteristics 3-12

3.2.3 AC Characteristics 3-15

3.3 LSI53C120 Mechanical Drawing 3-17

Appendix A Differential Wiring Diagram

Appendix B Glossary

Index

Customer Feedback

viii Contents

Figures

1.1 LSI53C120 SCSI Bus Device 1-2

1.2 SCSI Extender Application (SE to SE Mode of Operation) 1-5

1.3 SCSI Extender or Converter Application (SE to HVD Mode
of Operation) 1-5

1.4 SCSI Bus Electrical Isolation 1-6

2.1 LSI53C120 Block Diagram 2-2

2.2 LSI53C120 Signal Grouping 2-5

3.1 LSI53C120 Pin Diagram 3-2

3.2 LSI53C120 Functional Signal Grouping 3-3

3.3 Rise and Fall Time Test Conditions 3-13

3.4 SCSI Input Filtering 3-13

3.5 Hysteresis of SCSI Receiver 3-14

3.6 Input Current as a Function of Input Voltage 3-14

3.7 Output Current as a Function of Output Voltage 3-15

3.8 Clock Timing 3-16

3.9 Input/Output Timing 3-17

3.10 LSI53C120 Mechanical Drawing 3-18

A.1 LSI53C120 Differential Wiring Diagram A-2

ix

x

Tables

1.1 Modes of Operation 1-1

2.1 Direction Control Signals (B_SDIR(15-0, P0, P1), B_BSYDIR,
B_SELDIR, B_CD_DIR, B_IO_DIR, B_MSGDIR, B_REQDIR,
B_ACKDIR, B_ATNDIR and B_RSTDIR) Polarities 2-9

2.2 DIFF_MODE/ Control Signal Polarity 2-9

2.3 DIFF_SENSE Control Signal Polarity 2-10

2.4 RESET/ Control Signal Polarity 2-10

2.5 WS_ENABLE/ Signal Polarity 2-11

2.6 XFER_ACTIVE Signal Polarity 2-11

3.1 SCSI A Signal Description 3-4

3.2 SCSI B Signal Description 3-5

3.3 SCSI B Differential Signal Description 3-6

3.4 Chip Control Signal Description 3-7

3.5 SCSI Control Signal Description 3-7

3.6 Power and Ground Signal Description 3-7

3.7 No Connect Pins 3-8

3.8 Absolute Maximum Stress Ratings 3-8

3.9 Operating Conditions 3-9

3.10 SCSI Signals – A_SD(15-0)/, A_SDP(1-0)/, A_SREQ/,
A_SACK/, B_SD(15-0)/, B_SDP(1-0)/, B_SREQ/, B_SACK/ 3-9

3.11 SCSI Signals – A_SMSG, A_SI_O/, A_SC_D/, A_SATN/,
A_SBSY/, A_SSEL/, A_SRST/, B_SMSG, B_SI_O/,
B_SC_D/, B_SATN/, B_SBSY/, B_SSEL/, B_SRST/ 3-10

3.12 Input Signals – CLOCK, DIFF_SENSE, DIFF_MODE/*,
WS_ENABLE/* 3-10

3.13 Capacitance 3-10

3.14 Differential Signals - B_SDIR(15-0), B_SDIRP0, B_SDIRP1,
B_CD_DIR, B_IO_DIR, B_MSGDIR, B_REQDIR,
B_B_ACKDIR, B_BSYDIR, B_SELDIR, B_RSTDIR 3-11

3.15 Control Signals - RESET/ 3-11

3.16 Control Signals - XFER_ACTIVE 3-11

3.17 TolerANT Technology Electrical Characteristics 3-12

3.18 Clock Timing 3-15

3.19 Input Timing 3-16

3.20 Output Timing 3-16

xi

xii

Chapter 1
Introduction

This chapter describes the LSI53C120 Ultra SCSI Bus Expander and its
applications. It includes these topics:

• Section 1.1, “General Description,” page 1-1

• Section 1.2, “Features,” page 1-3

• Section 1.3, “Application Examples,” page 1-4

1.1 General Description

The LSI53C120 Ultra SCSI Bus Expander is a single chip solution
allowing the extension of device connectivity and/or cable length limits of
the SCSI bus. The LSI53C120 operates as a Ultra SCSI bus expander
when multiple single-ended to single-ended cables are connected
together while being electrically isolated from each other.TheLSI53C120
also operates as a SCSI bus converter when single-ended to differential
cables are connected together while being electrically isolated from each
other.

The LSI53C120 operates in two modes: single-ended to single-ended
(Extender Mode) or single-ended to High Voltage Differential (HVD)
(Converter Mode). For applications requiring SE to Low Voltage
Differential (LVD), use the LSI53C141 SCSI Bus Expander. Table 1.1
shows all modes of operation.

Table 1.1 Modes of Operation

Product Extender Converter

LSI53C120 SE to SE SE to HVD
LSI5353C141 SE to SE SE to LVD

LSI53C120 Ultra SCSI Bus Expander 1-1

In both SCSI Bus Extender and Converter modes, cable segments are
electrically isolated from each other. This feature maintains the signal
integrity of each cable segment. For bus isolation applications, the
LSI53C120 is ideally suited for the LSI53C875 Ultra SCSI controller.

The LSI53C120 provides additional control capability through the pin
level electrical isolation mode. This feature permits logical disconnection
of both the A-side bus and the B-side bus without disrupting SCSI
transfers currently in progress. For example, devices on the logically
disconnected B-side can be swapped out while the A-side bus remains
active.

The LSI53C120 is based upon bus expander technology resulting in
some signal filtering and re-timing to maintain signal skew budgets. In
addition, the LSI53C120 has no programmable registers, therefore, it
does not require any software.

Figure 1.1 LSI53C120 SCSI Bus Device

A-Side

Single-ended Wide Ultra SCSI Bus

(Data and Control)

Control Signals

40 MHz Oscillator

LSI53C120

SCSI Bus
Expander

B-Side

Single-ended Wide Ultra SCSI Bus

(Data and Control)

or

Differential Wide Ultra SCSI Bus

(Data and Control)

1-2 Introduction

1.2 Features

The LSI53C120 Ultra SCSI Bus Expander supports these features:

• Accepts any asynchronous or synchronous data transfer rates up to

the 40 MB/s rate of Wide Ultra SCSI

• Allows targets and initiators to connect either to the SCSI A-side or

SCSI B-side of the LSI53C120

• Does not consume a SCSI ID

• Can cascade up to three LSI53C120s in series

• Requires 40 MHz input clock

• Supports two modes of operation

– Single-ended to Single-ended Mode
– Single-ended to High Voltage Differential Mode

(with external transceivers)

• Connects two wide and/or narrow SCSI buses

– Extends Ultra SCSI cable lengths in certain applications
– Extends total number of connected Ultra SCSI devices

supported

• Supports TolerANT

®

active negation technology

• Includes complete support for SCSI-1, SCSI-2, and SCSI-3

• Does not require software

• Allows pin level SCSI bus disable mode

• Comes packaged in a 128-pin PQFP

• Includes TolerANT Technology

The LSI53C120 SCSI Bus Expander works with the extensive LSI Logic
LSI53C7xx and LSI53C8xx family of SCSI products. It also works with
other industry SCSI controllers, disk drives, and SCSI peripherals.
Advantages of the LSI53C120 are that it does not require any software
or consume a SCSI ID. This allows for easy integration and maximum
bus utilization. Adding the LSI53C120 to a SCSI bus environment
creates a low risk solution for applications requiring scalable device
connectivity and SCSI bus electrical isolation.

Features 1-3

Figure 1.1 on page 1-2 illustrates the connectivity of the LSI53C120 Ultra

SCSI Bus Expander device. A SCSI Single-ended (SE) bus connects
directly to the SCSI A-side. The interface signals are SCSI bus
compatible driver and receiver signals with no internal termination. The
SCSI B-side has the SE capable driver and receiver and also provides
the individual driver controls for external High Voltage Differential (HVD)
transceivers.

The LSI53C120 provides additional control capability through the pin
level SCSI bus disable mode. This feature allows logical disconnection of
both the A-side bus and B-side bus without disrupting transfers currently
in progress. For example, this feature allows electrical disconnection of
devices on the B-side to be swapped out while the A-side bus remains
active.

The TolerANT technology feature prevent glitches on the SCSI bus at
power-up or power-down, so other devices on the bus are also protected
from data corruption. For more detailed information about this
technology, refer to Section 2.1.1.1, “TolerANT Drivers and Receivers,”

page 2-3.

1.3 Application Examples

The following examples are typical applications for the LSI53C120 Ultra
SCSI Bus Expander. Many other configurations are possible and are only
limited by the imagination of the system architect.

1.3.1 Scalable Device Connectivity

Figure 1.2 illustrates how to use the LSI53C120 to increase the number

of devices to 15 on a 3 meter Ultra SCSI bus cable.

1-4 Introduction

Figure 1.2 SCSI Extender Application (SE to SE Mode of Operation)

Disk Subsystem

Single-ended (3 meters)

Ultra SCSI
Host Adapter

Terminator

LSI53C120

LSI53C120

LSI53C120

LSI53C8xx

Ultra SCSI Controller

Device 0

Device 1

Device 5

Ultra SCSI Drive Box

(1.5 meters)

Single-ended

Device 6

Device 10

Ultra SCSI Drive Box

(1.5 meters)

Single-ended

Ultra SCSI Drive Box

Device 11

Device 15

Single-ended

Figure 1.3 illustrates both SE to SE, and SE to HVD modes of the

LSI53C120 to create a redundant remote storage configuration.

Figure 1.3 SCSI Extender or Converter Application (SE to HVD Mode of Operation)

Dual Channel Ultra SCSI Host Adapter

LSI53C876

Dual Channel

Ultra SCSI

Controller

Devices 0 & 1

LSI53C120

Differential

Transceivers

Differential

Transceivers

LSI53C120

Differential (25 meters)

Terminator

LSI53C120

Differential

Transceivers

Single-ended (3 meters)

Differential

Transceivers

(1.5 meters)

Device 12

Device 14

Ultra SCSI Remote Storage Box

(1.5 meters)

Single-ended

Application Examples 1-5

Device 7

Device 11

Ultra SCSI Drive Box

(1.5 meters)

Single-ended

LSI53C120

Device 2

Device 6

Ultra SCSI Drive Box

(1.5 meters)

Single-ended

LSI53C120

1.3.2 SCSI Bus Electrical Isolation

Figure 1.4 illustrates how to use the LSI53C120 to electrically isolate an

external SCSI bus from an internal SCSI bus. This configuration ensures
externally attached peripherals will not affect the operation of internal
peripherals.

Figure 1.4 SCSI Bus Electrical Isolation

External

SCSI Bus

(Legacy Devices)

H.D. 68 pin

Terminator

Flash
ROM

Internal Ultra SCSI Bus

H.D. 68 pin

Terminator

LSI53C120

LSI53C8xx

Ultra SCSI

Controller

PCI Bus

1-6 Introduction

Chapter 2
Functional Description

This chapter describes all signals, their groupings and functions, and
includes these topics:

Section 2.1, “Interface Signal Descriptions,” page 2-1
Section 2.2, “SCSI Signal Descriptions,” page 2-4

2.1 Interface Signal Descriptions

The LSI53C120 has no programmable registers; therefore, no software
requirements. SCSI control signals control all LSI53C120 functions.

Figure 2.1 on page 2-2 is a diagram of the LSI53C120 device divided into

the following blocks:

• SCSI A-Side and B-Side Single-Ended Control Blocks that contain

TolerANT®Drivers and Receivers

• Re-timing Circuit

• Precision Delay Control

• State Machine Control

• Differential Control

LSI53C120 Ultra SCSI Bus Expander 2-1

Figure 2.1 LSI53C120 Block Diagram

A-Side

Single-ended

Wide Ultra SCSI Bus

Data and Control

Control Signals

B-Side

Single-ended

Wide Ultra SCSI Bus

Data and Control

Re-timing Circuit

Control

State

Machine

Control

or

SCSI Control Block

TolerANT Drivers and Receivers

High Voltage Differential

Transceiver Control

Wide Ultra SCSI Bus

Differential

Control

Chip Boundary

TolerANT Drivers and Receivers

Control

SCSI Control Block

Precision

Delay

Control

40 Mhz Clock Input

In its simplest form, the LSI53C120 passes data and parity from a source
bus to a load bus. The side asserting, deasserting or releasing the SCSI
signals is the source side. The model of the LSI53C120 represents
pieces of wire that allow corresponding SCSI signals to flow from one
side to the other side. The LSI53C120 monitors arbitration and selection
by devices on the bus so it can enable the proper drivers to pass the
signals along. In addition, the LSI53C120 does some signal re-timing to
maintain the signal skew budget from source bus to load bus.

2.1.1 SCSI A-Side and B-Side Single-Ended Control Blocks

In the Single-ended (SE) to Single-ended mode, the SCSI A-side pins
are connected internally to the corresponding SCSI B-side pins, forming
bi-directional connections to the SCSI bus.

The SCSI A-side and B-side SE control blocks connect to both targets
and initiators and accept any asynchronous or synchronous data transfer
rates up to the 40 Mbytes/s rate of Wide Ultra SCSI. TolerANT
technology is part of the SCSI A-side and B-side SE control blocks.

2-2 Functional Description

2.1.1.1 TolerANT Drivers and Receivers

The LSI53C120 features TolerANT technology, which includes active
negation on the SCSI drivers and input signal filtering on the SCSI
receivers. Active negation causes the SCSI Request, Acknowledge,
Data, and Parity signals to be actively driven HIGH rather than passively
pulled up by terminators.

TolerANT receiver technology improves data integrity in unreliable
cabling environments, where other devices would be subject to data
corruption. TolerANT receivers filter the SCSI bus signals to eliminate
unwanted transitions, without the long signal delay associated with RC­type input filters. This improved driver and receiver technology helps
eliminate double clocking of data, the single biggest reliability issue with
SCSI operations.

The benefits of TolerANT include increased immunity to noise on the
deasserting signal edge, better performance due to balanced duty
cycles, and improved SCSI transfer rates. In addition, TolerANT SCSI
devices prevent glitches on the SCSI bus at power-up or power-down, so
other devices on the bus are also protected from data corruption.

2.1.2 Re-timing Logic

The SCSI signals, as they propagate from one side of the LSI53C120 to
the other side, are processed by logic that re-times the bus signals as
needed to guarantee or improve required SCSI timings. The state
machine controls govern the re-timing logic to keep track of SCSI
phases, the location of initiator and target devices, and various timing
functions. In addition, the re-timing logic contains numerous precision
delay elements that are periodically calibrated by the Precision Delay
Control block in order to guarantee specified timings such as output
pulse widths, setup and hold times, and other elements.

2.1.3 Precision Delay Control

The Precision Delay Control block provides calibration information to the
precision delay elements in the Re-timing Logic block. This calibration
information provides precise timings as signals propagate through the
device. As the LSI53C120 voltage and temperature vary over time, the
Precision Delay Control block periodically updates the delay settings in

Interface Signal Descriptions 2-3