American Megatrends Pegasus User manual

Pegasus
Pentium® II
PCI ISA Motherboard
User's Guide
MAN-759
7/3/97

Pegasus PCI Motherboard User’s Guide
ii
© Copyright 1997 American Megatrends, Inc.
All rights reserved.
American Megatrends, Inc.
6145F Northbelt Parkway
Norcross, GA 30071
This publication contains proprietary information which is protected by copyright. No part of this publication may be reproduced, transcribed,
stored in a retrieval system, translated into any language or computer language, or transmitted in any form whatsoever without the prior written
consent of the publisher, American Megatrends, Inc.
Limited Warranty
Buyer agrees if this product proves to be defective, that American Megatrends, Inc. is only obligated to replace or refund the purchase price of
this product at American Megatrend's discretion according to the terms and conditions on the motherboard warranty card. American Megatrends
shall not be liable in tort or contract for any loss or damage, direct, incidental or consequential. Please see the Warranty Registration Card
shipped with this product for full warranty details.
Limitations of Liability
In no event shall American Megatrends be held liable for any loss, expenses, or damages of any kind whatsoever, whether direct, indirect,
incidental, or consequential, arising from the design or use of this product or the support materials provided with the product.
Trademarks
VESA is a registered trademark of the Video Electronics Standards Association.
Intel, Pentium. Pentium Pro, and Pentium II are registered trademarks of Intel Corporation.
MS-DOS, Microsoft Word, and Microsoft are registered trademarks of Microsoft Corporation. Microsoft Windows,
Windows NT, and Windows 95 are trademarks of Microsoft Corporation.
IBM, AT, XT, CGA, VGA, PS/2, OS/2, and EGA are registered trademarks of International Business Machines
Corporation.
Fujitsu is a registered trademark of Fujitsu America, Inc.
Motorola is a registered trademark of Motorola Corporation.
Hitachi is a registered trademark of Hitachi America, Ltd.
PNY is a registered trademark of PNY Corporation.
Oki is a registered trademark of Oki America, Inc.
NEC is a registered trademark of NEC Corporation.
Samsung is a registered trademark of Samsung Electronics Corporation.
Siemens is a trademark of Siemens Corporation.
Mitsubishi is a registered trademark of Mitsubishi Electronics of America.
Micron is a registered trademark of Micron Corporation.
SCO, Unix, and UnixWare are registered trademarks of the Santa Cruz Operation, Inc.
Toshiba is a registered trademark of Kabushiki Kaisha Toshiba.
All other brand and product names are trademarks or registered trademarks of their respective companies.
Revision History
7/3/97 Initial release.

Preface iii
Preface
To the OEM Thank you for purchasing the high performance American Megatrends
Pegasus Pentium II PCI ISA motherboard. This product is a state of the art
motherboard that includes the famous AMIBIOS. It is assumed that you have
also licensed the rights to use the American Megatrends documentation for
the American Megatrends Pegasus motherboard.
This manual was written for the OEM to assist in the proper installation and
operation of this motherboard. This manual describes the specifications and
features of the Pegasus PCI motherboard. It explains how to assemble a
system based on the Pegasus PCI motherboard and how to use the AMIBIOS
that is specifically designed for this motherboard.
This manual is not meant to be read by the computer owner who purchases a
computer with this motherboard. It is assumed that you, the computer
manufacturer, will use this manual as a sourcebook of information, and that
parts of this manual will be included in the computer owner's manual.
Technical Support If an American Megatrends motherboard fails to operate as described or
you are in doubt about a configuration option, please call technical support at
770-246-8645.
Warning
Do not use 16 MB x 36 (64 MB) SIMMs that have 36 chips per
SIMM. This type of 16 MB SIMM does not work reliably because of
excessive loading on the motherboard circuitry. If you must use 64
MB SIMMs, use only SIMMs that have 12 or 8 chips per SIMM.
Do not use 70 ns SIMMs. The system memory timing cycle on this
motherboard are very sensitive. This motherboard does not work
reliably with 70 ns SIMMs.

Pegasus PCI Motherboard User’s Guide
iv
American Megatrends BBS
The American Megatrends BBS permits OEMs, VARs, and system
integrators to access technical information about motherboard and BIOS
products. Product Engineering Change Notices, Tech Tips, Technical Notes,
and complete technical manuals are available.
Data Transmission Rates The American Megatrends BBS automatically handles modems with
data transmission rates from 1,200 to 28,800 bps.
BBS Phone Numbers The following table lists the characteristics of the BBS phone numbers.
The BBS requires no parity, eight data bits, and one stop bit.
Phone Number Characteristics
770-246-8780 28,800 baud rate. Supports v.34.
770-246-8781 28,800 baud rate. Supports v.34.
770-246-8782 Supports HST and v.42.
770-246-8783 Supports HST and v.42.
Web Site We invite you to access the American Megatrends world wide web site at:
http://www.megatrends.com.
Packing List
You should have received the following:
• a Pegasus Pentium II PCI ISA motherboard,
• two serial cables,
• one parallel cable,
• a diskette containing the American Megatrends DMI Wizard 95 software
utility,
• The DMI Wizard 95 User’s Guide,
• the SystemGuru User’s Guide,
• 4 diskettes containing the SystemGuru Server Management Software for
Windows NT,
• a Warranty Card, and
• the American Megatrends Pegasus Pentium II PCI ISA Motherboard
User's Guide.

Chapter 1 Hardware Installation 1
1Hardware Installation
Overview
The American Megatrends Pegasus PCI Pentium II ISA motherboard features
include:
• an Intel Pentium II CPU operating at 233, 266, 300 MHz or higher
speeds ,
• up to 768 MB of system memory on the motherboard,
• parity checking or ECC (Error Checking and Correction),
• PCI local bus throughput of 132 megabytes per second,
• the American Megatrends SystemGuru server management software,
• three ISA expansion slots, and
• four PCI expansion slots.
CPUs The Pegasus motherboard will support all Intel Slot1 CPUs operating at 233
MHz, 266 MHz, 300 MHz, or faster speeds.
PCI Bus Speed AMIBIOS automatically configures the PCI slots. The PCI slots are
synchronous with the CPU clock:
CPU External Clock Frequency PCI Expansion Slot Frequency
66 MHz 33 MHz
60 MHz 30 MHz
Onboard I/O The Pegasus motherboard includes:
• two 40-pin IDE connectors for 1 – 4 IDE drives,
• a 34-pin floppy drive connector,
• two serial port connectors,
• a 25-pin parallel port connector,
• a keyboard DIN connector,
• two 4-pin USB ports, and
• a 9-pin berg mouse connector.
Server Management Software The American Megatrends SystemGuru server management
software is included with the Pegasus motherboard. SystemGuru uses the
LM78 interface to constantly monitor and report the CPU temperature, fan
speed, ECC memory errors, ambient temperature, CPU voltage, system
voltage and other user-specified system status information to any remote
client computer. See the American Megatrends SystemGuru User’s Guide for
additional information.

Pegasus PCI Motherboard User’s Guide
2
Pegasus PCI Dimensions
The motherboard is approximately 8.55” by 13” (baby AT size). The
motherboard height restrictions are shown below:
Warning
This motherboard contains sensitive electronic components
that can be easily damaged by static electricity. Follow the
antistatic instructions carefully to ensure correct installation
and to avoid damage.

Chapter 1 Hardware Installation 3
Pegasus PCI Motherboard Layout
P1
BANK0BANK2 BANK1
P3
J8 Parallel
J4
Floppy
J1
PS/2
Mouse
J2
COM2
J10
Kbd

Pegasus PCI Motherboard User’s Guide
4
Step 1 Unpack the Motherboard
Step Action
1Inspect the cardboard carton for obvious damage. If damaged,
call 770-246-8645. Leave the motherboard in its original
packing.
2Perform all unpacking and installation procedures on a ground-
connected anti-static mat. Wear an anti-static wristband
grounded at the same point as the anti-static mat. Or use a
sheet of conductive aluminum foil grounded through a 1
megohm resistor instead of the anti-static mat. Similarly, a
strip of conductive aluminum foil wrapped around the wrist
and grounded through a 1 megohm resistor serves the same
purpose as the wristband.
3Inside the carton, the motherboard is packed in an anti-static
bag, and sandwiched between sheets of sponge. Remove the
sponge and the anti-static bag. Place the motherboard on a
grounded anti-static surface component side up. Save the
original packing material.
4Inspect the motherboard for damage. Press down on all ICs
mounted in sockets to verify proper seating. Do not apply
power to the motherboard if it has been damaged.
5If the motherboard is undamaged, it is ready to be installed.
Set Jumpers Set all jumpers and install the CPU before placing the motherboard in the
chassis.
Avoid Static Electricity
Static electricity can damage the motherboard and other computer
components. Keep the motherboard in the anti-static bag until it is to be
installed. Wear an anti-static wrist grounding strap before handling the
motherboard. Make sure you stand on an anti-static mat when handling the
motherboard.
Avoid contact with any component or connector on any adapter card, printed
circuit board, or memory module. Handle these components by the mounting
bracket.

Chapter 1 Hardware Installation 5
Step 2 Configure CPU Speed
J16, J17, J18, and J19 are 2-pin bergs that help set the CPU speed. J21 is a 3-
pin berg and J22 is an 8-pin berg that set the CPU speed, as described below.
A visual display of the CPU speed jumper settings is shown below.
CPU
Speed J16 J17 J18 J19 J21 J22
200
MHz Shorted OPEN Shorted OPEN Short Pins 1-2 Short Pins 1-2 Short Pins 5-6
Short Pins 7-8
233
MHz Shorted OPEN Shorted OPEN Short Pins 1-2 Short Pin 5-6 Short Pin 7-8
266
MHz Shorted OPEN Shorted OPEN Short Pins 1-2 Short Pins 1-2 Short Pin 3-4
Short Pin 7-8
300
MHz Shorted OPEN Shorted OPEN Short Pins 1-2 Short Pins 3-4 Short Pins 7-8
Important
Please contact American Megatrends technical support at
770-246-8645 to support a CPU running at other speeds.

Pegasus PCI Motherboard User’s Guide
6
Step 3 Configure CPU Voltage
J12 J12 is a 10-pin berg that sets the voltage for the Pentium II CPU in CPU
Slot1.
Core CPU Voltage J5 and J15 Setting
3.50V Short Pins 2-7
Short Pins 3-8
Short Pins 4-9
Short Pins 5-10
3.40V Short Pins 2-7
Short Pins 3-8
Short Pins 4-9
3.3V Short Pins 2-7
Short Pins 3-8
Short Pins 5-10
3.2V Short Pins 2-7
Short Pins 3-8
3.1V Short Pins 2-7
Short Pins 4-9
Short Pins 5-10
3.0V Short Pins 2-7
Short Pins 4-9
2.9V Short Pins 2-7
Short Pins 5-10
2.8V (Factory Setting) Short Pins 2-7
2.7V Short Pins 3-8
Short Pins 4-9
Short Pins 5-10
2.6V Short Pins 3-8
Short Pins 4-9
2.5V Short Pins 3-8
Short Pins 5-10
2.4V Short Pins 3-8
2.3V Short Pins 4-9
Short Pins 5-10
2.2V Short Pins 4-9
2.1V Short Pins 5-10
2.05V Short Pins 1-6
Short Pins 2-7
Short Pins 3-8
Short Pins 4-9
Short Pins 5-10
2.0V Short Pins 1-6
Short Pins 2-7
Short Pins 3-8
Short Pins 4-9
1.95V Short Pins 1-6
Short Pins 2-7
Short Pins 3-8
Short Pins 5-10
1.90V Short Pins 1-6
Short Pins 2-7
Short Pins 3-8