LSI LSI21002 User Manual

USER’S

GUIDE

LSI21002 PCI to
Dual Channel SCSI
Host Adapter

Version 1.1

November 2000

®

S14001.A

Electromagnetic Compatibility Notices

This device complies wit h Part 15 of the FCC Rules. Operation is subject to the following two conditions:

1. This device may not cause harmful interference, and

2. This device must accept any interference received, including interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to par t 15

of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio communications. However,
there is no guarantee that interference will not occur in a particular installation. If this equipment does cause har mful
interference to radio or television reception, which can be determined by turning the equipment off and on, the user
is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and the receiver.

• Connect the equipment into an outlet on a circuit different from that to which the rece iver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

Shielded cables for SCSI connection external to the cabinet are used in the compliance testing of this Product. LSI
Logic is not responsible for any radio or television interference caused by unauthorized modification of this equipment
or the substitution or at tachment of connecting cables and equipment other than those specified by LSI Logic. The
correction of interferences caused by such unauthorized modification, s ubstitution, or atta chment will be the
responsibility of the user.

The LSI Logic LSI21002 is tested to comply with FCC standards for home or office use.

This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du

Canada.

This is a Class B product based on the standard of the Voluntary Control Council for Interference from Information
Technology Equipment (VCCI). If this is used near a radio or television receiver in a domestic environment, it may
cause radio interference. Install and use the equipment according t o the instruction manual.

LSI Logic Corporation
North American Headquarters
Milpitas, CA

408.433.8000

ii

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 DB15-000097-01, Second Edition (November 2000)
This document describes the LSI Logic LSI21002 PCI to Dual Channel SCSI
Host Adapter and will remain the official reference source for all
revisions/releases of this product until rescinded by an update.

To receive product literature, visit us at http://www.lsilogic.com.

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 par ties.

Copyright © 1999–2000 by LSI Logic Corporation. All rights reserved.
TRADEMARK ACKNOWLEDGMENT

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

iii

iv

Preface

This book is the primary ref erence and user’s guide for the LSI Logic
LSI21002 PCI to Dual Channel SCSI Host Adapter. It describes how to
install and configure the LSI21002 host adapter board in a PCI computer
system. Basic information on setting up the SCSI bus is also provided.

LSI Logic Technical Support

The entire LSI Logic host adapter solution has been designed for ease
of use. However, if you require additional assistance, please contact the
LSI Logic Technical Support Hot Line at [phone]. The hour s of
operation are from 7:30 a.m. to 4:30 p.m. (MST), Monday through Friday.

Organization

Before calling, please have the following information:

• Which LSI Logic host adapter are you installing?

• What system are you installing into?

• What SCSI devices are you connecting to the bus?

• How is your system configured?

It is also helpful if you are at your system when you call.

This document has the following chapters and appendixes:

• Chapter 1, Using the LSI21002, defines the interfaces and

characteristics of the LSI21002.

• Chapter 2, Installing the LSI21002, provides quick and detailed

installation instructions.

Preface v

• Chapter 3, Configuring the Host Adapter, describes the SCSI

BIOS Configuration Utility to configure adapter and device settings.

• Appendix A, Technical Specifications, describes the ph ysical and

operational environments of the LSI21002.

• Appendix B, Glossary, provides definitions of various terminology

that is referenced throughout this user’s guide.

Related Publications

PCI Storage Device Management System SDMS 4.0 User’s Guide ,

Order Number S14007.A

Revision Record

Revision Date Remarks

1.0 3/99 Final version.

1.1 11/00 All product names changed from SYM to LSI.

vi Preface

Contents

Chapter 1 Using the LSI21002

1.1 General Description 1-1

1.2 Features 1-2

1.2.1 PCI Interface 1-2

1.2.2 SCSI Interface 1-2

1.2.3 Board Characteristics 1-3

1.3 Interface Descriptions 1-4

1.3.1 The PCI Interface 1-4

1.3.2 The SCSI Interface 1-4

1.3.3 SCSI Activity LED Interface 1-5

1.3.4 Wide Ultra2 SCSI 1-5

Chapter 2 Installing the LSI21002

2.1 Quick Installation Procedur e 2-1

2.2 Detailed Installation Procedure 2-3

2.2.1 Before You Start 2-3

2.2.2 Inserting the Host Adapter 2-4

2.2.3 Connecting the SCSI Peripherals 2-6

2.2.4 SCSI Bus Termination 2-15

2.3 Setting Interrupts (Exceptional Cases) 2-24

2.4 Completing the Installation 2-25

Chapter 3 Configuring the Host Adapter

3.1 When to Configure the LSI21002 3-1

3.2 Starting the SCSI BIOS Configuration Utility 3-2

3.2.1 Configuration Utility Main Menu 3-3

3.2.2 Utilities Menu 3-7

3.3 Exiting the SCSI BIOS Configuration Utility 3-14

Contents vii

Appendix A Technical Specifications

A.1 Physical Environment A-1

A.1.1 Physical Characteristics A-2
A.1.2 Electrical Characteristics A-3
A.1.3 Thermal, Atmospheric Characteristics A-3
A.1.4 Electromagnetic Compliance A-4
A.1.5 Safety Characteristics A-4

A.2 Operational Environment A-4

A.2.1 The PCI Interface A-4
A.2.2 The SCSI Interface A-7

Appendix B Glossary

Index

Customer Feedback

Figures

2.1 Hardware Connections for the LSI21002 2-5

2.2 Inserting the Host Adapter 2-6

2.3 SCSI Cables 2-7

2.4 Internal SCSI Ribbon Cable to Host Adapter 2-8

2.5 Internal SCSI Ribbon Cable to Internal SCSI Device
Connection 2-9

2.6 Connecting Additional Internal SCSI Devices 2-10

2.7 Multiple Internal SCSI Devices Chained Together 2-11

2.8 SCSI LED Connector 2-12

2.9 External Cable to Host Adapter 2-13

2.10 External Cable to External SCSI Device 2-14

2.11 Multiple External SCSI Devices Chained Together 2-15

2.12 Internal SCSI Device Termination 2-17

2.13 External SCSI De vice Termination 2-18

2.14 Internal and External SCSI Device Termination 2-20

2.15 Internal and Internal SCSI Device Termination 2-21

3.1 Main Menu 3-4

viii Contents

Tables

3.2 Change Status on Next Boot Menu 3-5

3.3 Boot Order Menu 3-5

3.4 Adapter Configuration Menu 3-6

3.5 Utilities Menu 3-7

3.6 Adapter Setup Menu 3-8

3.7 Device Selections Menu 3-11

3.8 Device Selections Menu (Cont.) 3-12

A.1 LSI21002 Mechanical Drawing A-2

1.1 Standard Cables 1-6

2.1 SCSI ID Record 2-23

2.2 Setting Interrupts 2-24

3.1 Global Default Settings 3-1

3.2 Device Default Settings 3-2

A.1 Maximum Power Requirements A-3
A.2 PCI Connector J1 Front Side Signals A-5
A.3 PCI Connector J1 Back Side Signals A-6
A.4 SCSI Connector J2, Channel A, Internal A-8
A.5 SCSI Connector J3, Channel A, External A-9
A.6 SCSI Connector J4, Channel A, Internal A-10
A.7 SCSI Connector J5, Channel B, Internal A-11
A.8 Connector J6 Signals A-12

Contents ix

xContents

Chapter 1
Using the LSI21002

This chapter describes the LSI21002 PCI to Dual Channel SCSI Host
Adapter interfaces to PCI computer systems and includes these topics:

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

• Section 1.2, “Features,” page 1-2

• Section 1.3, “Interface Descriptions,” page 1-4

1.1 General Description

The LSI21002 provides internal and external SCSI interfaces to PCI
computer systems that require BIOS supporton the add-in SCSI adapter.
It will be referred to as the LSI21002 throughout this manual. Installing
the LSI21002 in your PCI system allows connection of SCSI devices over
aSCSIbus.

The dual channel LSI21002 provides 16-bit Low Voltage Differential
(LVD) and Single-Ended (SE) SCSI solutions for your computer, using
only one PCI slot. This board supports legacy Fast SCSI devices, Ultr a
SCSI devices, and the newest Ultra2 SCSI devices.

Channel A supports only the SE mode. Channel B supports SE and LVD
modes of operation.

The Storage Device Management System (SDMS™) software operates
the board. The design of the board does not prevent other software from
being used with it.

This guide, along with the PCI Storage Device Management System
SDMS 4.0 User’s Guide, contains product information and installation
instructions to help you gain the full benefits of the LSI21002.

LSI21002 PCI to Dual Channel SCSI Host Adapter 1-1

1.2 Features

This section provides a high level overview of the PCI Interface, the SCSI
Interface, and Board Characteristics for the LSI21002.

1.2.1 PCI Interface

• True PCI multifunction controller for maximum performance

• 32-bit (33 MHz) DMA bus master

• Bursts up to 128 Dwords across the PCI Bus

• Zero wait-state bus master data bursts up to 110 Mbytes/s

• Prefetches up to 8 Dwords of SCRIPTS instructions

• PCI Universal 3.3 V/5 V bus support

• Supports PCI write and invalidate, read line, and read multiple

(@33 MHz)

commands

1.2.2 SCSI Interface

• Two separate SCSI channels

• Wide Ultra2 SCSI LVD synchronous transfers as fast as 80 Mbytes/s

(Channel B)

• Wide Ultra SCSI SE synchronous transfers as fast as 40 Mbytes/s

(Channel A)

• SCSI synchronous offset up to 31

• Supports variable block size and scatter/gather data transfers

• 16-bit SE/LVD

• Four connectors:

50-pin high density for the external Channel A
50-pin narrow (ribbon) for internal Channel A
68-pin high density for internal Channels A and B

• Fast, Ultra, and Ultra2 data transfer capability

• SCSI termination power (TERMPWR) source with auto-resetting

circuit breaker and TERMPWR shorted LED for each channel

1-2 Using the LSI21002

• Supports SE and LVD signaling with automatic termination

– Channel A is SE only with autosense termination
– Channel B is SE or LVD with termination permanently enabled

• Performs complex bus sequences without interrupts, including

restore data pointers

• SCSI Plug and Play

• SCSI Configured AutoMatically (SCAM) See Chapter 3, "Configuring

the Host Adapter," for details about SCAM capability

• Flash R OM for BIOS storage

• Serial EEPROM for each channel for user configuration utility and

SCAM information storage

• SCSI activity LED for each channel

• LSI53C896 includes 8 Kbytes internal RAM per channel for

SCRIPTS instruction storage

1.2.3 Board Characteristics

• PCI board dimensions

Approximately 190.5 mm x 96.52 mm (7.5 x 3.8 inches)

• Universal 32-bit PCI card edge connector

• ISA/EISA bracket

Features 1-3

1.3 Interface Descriptions

This section provides a more detailed explanation about the PCI
Interface, the SCSI Interface, the SCSI Activity LED Interface, and Wide
Ultra2 SCSI.

1.3.1 The PCI Interface

PCI is a high-speed standard local bus for interfacing a number of I/O
components to a PC processor and memory subsystem. The PCI
functionality for the LSI21002 is contained within the LSI53C896 PCI
Dual Channel SCSI Multifunction Controller. The LSI53C896 connects
directly to the PCI bus and generates timing protocol in compliance with
the PCI specification.

The PCI interface operates as a 32-bit DMA bus master. The connection
is made through edge connector J1 (see Figure 2.1). The signal
definitions and pin numbers conform to the PCI Local Bus Specification
Revision 2.1 standard. The LSI21002 conforms to the PCI univ ersal
signaling environment for a 5 V or 3.3 V PCI bus.

1.3.2 The SCSI Interface

The SCSI functionality for the LSI21002 is contained within the
LSI53C896 chip. The LSI53C896 connects directly to the two SCSI
buses for SE or LVD SCSI applications and generates timing and
protocol in compliance with the SCSI standard. One SCSI interface
operates at a burst transfer rate of up to 40 Mbytes/s for wide Ultra SCSI
transfers, and the other up to 80 Mbytes/s for wide Ultra2 SCSI transfers.

Channel A is SE only with active autosensing termination. The
Channel A interface is made through connectors J2, J3, and J4.
Connector J2 is a 68-pin high density latching right angle receptacle for
internal SCSI connections. Connector J3 is a 50-pin high density right
angle receptacle that protrudes throughout the ISA/EISA bracket.
Connector J4 is a 50-pin narrow (ribbon) internal connector.

Channel B may be either SE or LVD with active termination always
enabled. The Channel B interface is made through connector J5. J5 is a
68-pin high density latching right angle connector for internal SCSI
connections.

1-4 Using the LSI21002

See Figure 2.1 for the location of these connectors.
The LSI21002 supplies SCSI bus TERMPWR through a blocking diode

and self-resetting 1.5 A short circuit protection device. An on-board LED
lights up when TERMPWR is shorted and has turned off.

A 40 MHz oscillator is installed on the LSI21002 to provide the clock
frequency to the LSI53C896 that is necessary to support SCSI transfers.

1.3.3 SCSI Activity LED Interface

The LSI21002 LED interface is a four-wire arrangement that allows
connection of an LED harness to the board. The connector on the
LSI21002 is J6 for both channels. See Table A.7 in Appendix A for the
signal name and pin numbers for this LED interface.

1.3.4 Wide Ultra2 SCSI

The LSI21002 has full support for Wide Ultra2 SCSI. This interface is an
extension of the SCSI-3 family of standards that expands the bandwidth
of the SCSI bus to allow faster synchronous data transfers, up to
80 Mbytes/s. Wide Ultra2 SCSI provides a doubling of the data rate over
the Ultra SCSI interface, while it allows increased cable length and more
devices than Ultra SCSI interfaces.

Special SCSI cables are specified for operation with Wide Ultra and
Ultra2 SCSI devices, and you must consider the total number of devices
and the length of your SCSI bus when setting up y our system. The
section on connecting your SCSI peripherals in Chapter 2, "Installing the

LSI21002," provides a more detailed explanation of SCSI bus

connections. See Table 1.1for maximum bus lengths in meters.
When you purchased the LSI21002 kit, the cable provided in the kit is

matched for a Fast/Ultra/Ultra2 SE or LVD operation. This cable also has
built-in LVD termination since most Ultra2 hard disk drives are not made
with on-board LVD termination.

Interface Descriptions 1-5

Table 1.1 Standard Cables

Maximum Bus Length, Meters

1

STA Term SE LVD Maximum Devices
Wide Ultra SCSI 1.5 see note
Wide Ultra SCSI 3 see note
Wide Ultra2 SCSI see note

3

12 16

2

2

8
4

1. This parameter may be exceeded in point-to-point and engineered

applications.

2. LVD was not defined in the original SCSI standards for this speed. If all

deviceson the bus support LVD, then 12-meter operation is possible at this
speed. However, if any device on the bus is SE only, then the entire bus
switches to SE mode, and the distances in the SE column apply.

3. SE and high power differential are not defined at Ultra2 speeds.

1-6 Using the LSI21002

Chapter 2
Installing the LSI21002

This chapter describes installing the LSI21002 into PCI computer
systems and includes these topics:

• Section 2.1, “Quick Installation Procedure,” page 2-1

• Section 2.2, “Detailed Installation Procedure,” page 2-3

• Section 2.3, “Setting Interrupts (Exceptional Cases),” page 2-24

• Section 2.4, “Completing the Installation,” page 2-25

2.1 Quick Installation Procedure

This section provides quick setup instructions for the experienced
computer user with prior host adapter installation and SCSI bus setup
experience. If you prefer more detailed guidance for installing the
LSI21002, please follow the instructions in Section 2.2, “Detailed

Installation Procedure.”

For safe and proper installation, check the user’s manual that was
supplied with your computer and perform the following steps.

Step 1. Before proceeding, ground yourself so that a static discharge

does not damage the board. Remove the LSI21002 from the
packing and check that it is not damaged. An example of this

host adapter board is shown in Figure 2.1.
Step 2. Switch off and unplug the system.
Step 3. Remove the cabinet cover on your computer to access the PCI

slots.

Caution.

Ground yourself by touching a metal surface before
handling boards. Static charges on your body can damage
electronic components. Handle plug-in boards by the edge;

LSI21002 PCI to Dual Channel SCSI Host Adapter 2-1

do not touch board componentsor gold connector contacts.
The use of a static ground strap is recommended.

Step 4. Locate the slots for the PCI plug-in board installation. A 32-bit

slot should be used. The LSI21002 will work in a 64-bit slot, but

only 32 bits are used. The LSI21002 requires a PCI slot that

allows bus master operation. See Figure 2.2.
Step 5. Remove the blank panel on the back of the computer aligned

with the PCI slot that you intend to use. Save the bracket screw.
Step 6. Carefully insert edge connector J1 of the host adapter into the

PCI slot. Make sure the edge connector is properly engaged

before pressing the board into place. See the example shown

in Figure 2.2.

Note.

You may notice that the components on the PCI host
adapter face the opposite way from those on other non-PCI
plug-in boards you have in your system. This is correct, and
the board is keyed to go in only one way.

Step 7. The bracket around connector J3 should fit where the blank

panel was removed. Secure it with the bracket screw before

making the internal and external SCSI bus connections (see

Figure 2.2).

Step 8. If y ou are connecting any internal SCSI devices, plug a 68-pin

connector on the end of the internal SCSI ribbon cable into

connector J2 or J5, or plug a 50-pin connector into J4 for an

8-bit SCSI (see Figure 2.1).Makecertaintomatchpin1onall

connectors.

Note.

It is possible to use both internal connectors if no external
devices are attached to the host adapter. You may use only
two of the three connectors at once.

Step 9. Connect your computer’s LED cable if desired. This LED cable

drives the front panel LED found on most PC cabinets to

indicate activity on the SCSI bus. See Table A.7 in Appendix A

for the signal name and pin numbers for this LED interface.
Step 10. Replace the cabinet cover as described in the user’s manual for

Step 11. Make all external SCSI bus connections.

2-2 Installing the LSI21002

your computer.

Remember: The SCSI bus requires proper termination and no duplicate

SCSI IDs.

Step 12. Refer to the PCI Storage Device Management System SDMS

4.0 User’s Guide (or the guide for the software that you will use)

to load the driver software f or your particular operating system.

2.2 Detailed Installation Procedure

This section provides step-by-step instructions for installing your
LSI21002 and connecting it to your SCSI peripherals. If you are
experienced in these tasks, you may prefer to use Section 2.1, “Quick

Installation Procedure.” If you are not confident that you can perform the

tasks as described here, LSI Logic suggests getting assistance.

2.2.1 Before You Start

Before you star t, look through the task list below to get an overall idea
of the steps to perform.

• Open your PC cabinet and select an open PCI slot

• Insert the host adapter

• Connect your internal and external SCSI peripherals

• Terminate the SCSI bus

• Set the peripheral SCSI IDs

• Make any configuration changes

• Replace your PC cabinet cover

• Install the software

The SCSI host adapter acts on your computer’s behalf as the host to
your suite of SCSI peripherals. Each chain of SCSI peripheral devices
and their host adapter work together, and they are referred to as a SCSI
bus.

Detailed Installation Procedure 2-3

2.2.2 Inserting the Host Adapter

For safe and proper installation, check the user’s manual supplied with
your computer and perform the following steps:

Step 1. Before proceeding, ground yourself so that a static discharge

does not damage the board. Remove the LSI21002 from the

packing and check that it is not damaged. An example of this

host adapter board is shown in Figure 2.1.
Step 2. Switch off and unplug power cords for all components in your

system.
Step 3. Remove the cabinet cover on your computer to access the PCI

slots.

Caution: Ground yourself by touching a metal surface before

removing the cabinet cover. Static charges on your body
can damage electronic components. Handle plug-in boards
by the edge; do not touch board components or gold
connector contacts. The use of a static ground strap is
recommended.

Step 4. Locate the slots for the PCI plug-in board installation. A 32-bit

slot should be used. The LSI21002 will work in a 64-bit slot, but

only 32 bits are used. The LSI21002 requires a PCI slot that

allows bus master operation. See Figure 2.2.
Step 5. Remove the blank panel on the back of the computer aligned

with the PCI slot that you intend to use. Save the bracket screw.
Step 6. Carefully insert edge connector J1 (see Figure 2.1) of the host

adapter into the PCI slot. Make sure the edge connector is

properly engaged before pressing the board into place as

shown in Figure 2.2.
Step 7. You may notice that the components on the PCI host adapter

face the opposite way from those on other non-PCI adapter

boards you have in your system. This is correct, and the board

is keyed to go in only one way.

2-4 Installing the LSI21002

Step 8. The bracket around connector J3 (see Figure 2.1) should fit

where you removed the blank panel. Secure it with the bracket

screw (see Figure 2.2) before making the internal and external

SCSI bus connections.

Figure 2.1 Hardware Connections for the LSI21002

Channel B 68-Pin

Internal High
Density SCSI
Connector J5

Channel A 68-Pin

Internal High
Density SCSI
Connector J2

Channel A 50-Pin

External HD SCSI

Connector J3

Channels A and B
Busy LED
Connector J6

Channel A 50-Pin
Internal Narrow SCSI
Connector J4

LSI21002 PCI Bus
Edge Connect or J1

Detailed Installation Procedure 2-5

Figure 2.2 Inserting the Host Adapter

Bracket Screw

2.2.3 Connecting the SCSI Peripherals

All internal SCSI bus connections to the LSI21002 are made with an
unshielded, 68- or 50-conductor ribbon cable (see Figure 2.3). On e side
of this cable is marked with a color to indicate the pin-1 side. The
connectors on this cable are keyed to ensure a proper pin-1 connection.
Use Ultra/Ultra2 rated cables for these bus speeds. (See Table 1.1 in

Chapter 1.)

2-6 Installing the LSI21002

32-bit Slot

64-bit Slots

For convenience, Channel A also has a 50-pin narr ow (ribbon)connector.
Some internal cables come with an SE/LVD terminator on one end. This
end should be furthest from the host adapter.

All external SCSI bus connections to the LSI21002 are made with a
shielded, 50-pin high density cable (see Figure 2.3). The connectors on
this cable are always keyed to ensure a proper pin-1 connection.

Figure 2.3 SCSI Cables

SCSI Cable for Internal Connections

68-Pin High Density

and/or

50-Pin Low Density

SCSI Cable for External Co n nect ion s

50-Pin High Density

Detailed Installation Procedure 2-7

2.2.3.1 Making Internal SCSI Bus Connections

This section provides step-by-step instructions about making internal
SCSI bus connections:

Step 1. To connect an internal SCSI device, plug the 68- pin connector

end of a wide internal SCSI ribbon cable into connector J2 or
J5. See the example in Figure 2.4.

Figure 2.4 Internal SCSI Ribbon Cable to Host Adapter

J2

J5

J3

J4

2-8 Installing the LSI21002

Step 2. Plug the 68-pin connector on the other end of the wide internal

SCSI ribboncable into the SCSI connector on the internal SCSI
device. Pin 1 must match on all connections. An example of this
connection appears in Figure 2.5.

Figure 2.5 Internal SCSI Ribbon Cable to Internal SCSI Device

Connection

Detailed Installation Procedure 2-9

Step 3. To plug in additional internal SCSI devices, use an internal

SCSI ribbon cable with the required number of connectors
attached along its length. See the example in Figure 2.6.

Figure 2.6 Connecting Additional I nternal SCSI Devices

2-10 Installing the LSI21002