American Megatrends Enterprise-IV User manual

American Megatrends, Inc.
Series 87 Enterprise-IV
80486 EISA VLB
Motherboard
User's Guide
MAN-687
9/8/94

© Copyright 1994 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 of the warranty card accompanying the Enterprise-IV
motherboard. 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
American Megatrends acknowledges the following trademarks:
Intel is a registered trademark of Intel Corporation.
MS-DOS, Xenix, and Microsoft are registered trademarks of Microsoft Corporation. Microsoft Windows and Windows NT are trademarks of Microsoft Corporation.
IBM, AT, PS/2, VGA, OS/2, and EGA are registered trademarks of International Business Machines Corporation. XT and CGA are trademarks of International Business Machines Corporation.
Fujitsu is a registered trademark of Fujitsu America, Inc.
Motorola is a registered trademark of Motorola 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.
Unix is a registered trademark of American Telephone and Telegraph Company Bell Laboratories.
Weitek is a trademark of Weitek, Inc.
Toshiba is a registered trademark of Kabushiki Kaisha Toshiba.
Revision History
6/8/93 Initial release.
10/6/93 Add new AMIBIOS Setup options.
9/8/94 Added information from errata sheets.

Enterprise-IV EISA VLB Motherboard User's Guide
iii
Table of Contents
Chapter 1 Introduction to VL-Bus...................................................................................................................................................................... 1
Chapter 2 Enterprise-IV Description.................................................................................................................................................................. 3
Chapter 3 Installation.......................................................................................................................................................................................... 11
Step 1 Unpack the Motherboard ......................................................................................................................................... 11
Step 2 Set Switch and Jumper Options............................................................................................................................... 13
Step 3 Install Memory......................................................................................................................................................... 16
Step 4 Install Upgrade Processor ........................................................................................................................................ 19
Step 5 Install the Motherboard............................................................................................................................................ 22
Step 6 Connect the Power Supply....................................................................................................................................... 24
Step 7 Connect the Keyboard.............................................................................................................................................. 27
Step 8 Connect the Mouse.................................................................................................................................................. 27
Step 9 Connect Cables........................................................................................................................................................ 28
Step 10 Install Adapter Cards ............................................................................................................................................. 31
Step 11 Perform Initial Test and Configuration.................................................................................................................. 38
Chapter 4 AMIBIOS Power-On Self Test.......................................................................................................................................................... 39
Chapter 5 AMIBIOS Setup................................................................................................................................................................................. 47
Section 1 Running AMIBIOS Setup..................................................................................................................................................... 49
Section 2 STANDARD CMOS SETUP ............................................................................................................................................... 53
Date And Day Configuration.............................................................................................................................................. 53
Time Configuration ............................................................................................................................................................ 53
Hard Disk Drive C: and D: ................................................................................................................................................. 54
Using Auto Detect Hard Disk............................................................................................................................................. 54
Hard Disk Drive Types....................................................................................................................................................... 55
Floppy Drive A and Floppy Drive B:.................................................................................................................................. 56
Primary Display.................................................................................................................................................................. 56
Keyboard............................................................................................................................................................................. 56
Section 3 ADVANCED CMOS SETUP............................................................................................................................................... 57
Typematic Rate Programming............................................................................................................................................ 58
Typematic Rate Delay......................................................................................................................................................... 58
Typematic Rate................................................................................................................................................................... 58
Mouse Support Option........................................................................................................................................................ 58
Above 1 MB Memory Test................................................................................................................................................. 58
Memory Test Tick Sound .................................................................................................................................................. 59
Memory Parity Error Checking........................................................................................................................................... 59
System Boot Up Num Lock................................................................................................................................................ 59
Floppy Drive Seek At Boot ................................................................................................................................................ 59
System Boot Up Sequence ................................................................................................................................................. 59
System Boot UP CPU Speed............................................................................................................................................... 60
External Cache Memory..................................................................................................................................................... 60
Internal Cache Memory ...................................................................................................................................................... 60
Password Checking Option................................................................................................................................................. 60
Video ROM Shadow C000,32K......................................................................................................................................... 61
Adaptor ROM Shadow C800,32K...................................................................................................................................... 61
Adaptor ROM Shadow D000,64K...................................................................................................................................... 61

Preface
iv
Table of Contents, Continued
Chapter 5 AMIBIOS Setup, cont'd
Adaptor ROM Shadow E000,64K...................................................................................................................................... 61
System ROM Shadow F000,64K........................................................................................................................................ 62
Shadow RAM Write Protection .......................................................................................................................................... 62
Boot Sector Virus Protection .............................................................................................................................................. 63
LBD Sampling Point........................................................................................................................................................... 63
Cache Write Back............................................................................................................................................................... 63
Non-Cacheable Area 1........................................................................................................................................................ 64
Non-Cacheable Area 1 Size ................................................................................................................................................ 64
Non-Cacheable Area 1 Start ............................................................................................................................................... 64
I/O Recovery Select ............................................................................................................................................................ 65
Hidden Refresh................................................................................................................................................................... 65
Section 4 ADVANCED CHIPSET SETUP.......................................................................................................................................... 67
On Board Serial Port 1........................................................................................................................................................ 67
On Board Serial Port 2........................................................................................................................................................ 68
On Board Parallel Port........................................................................................................................................................ 68
On Board Floppy Controller ............................................................................................................................................... 68
On Board IDE Controller.................................................................................................................................................... 68
Section 5 AMIBIOS Password Support................................................................................................................................................ 69
Section 6 Hard Disk Utility.................................................................................................................................................................. 71
Appendix A Temperature and Power Considerations...................................................................................................................................... 79
Appendix B Heat Dissipation.............................................................................................................................................................................. 81
Appendix C EISA Configuration Worksheets................................................................................................................................................... 83
Appendix D Flash EPROM Support ................................................................................................................................................................ 101
Index.....................................................................................................................................................................................................................109

Enterprise-IV EISA VLB Motherboard User's Guide
v
Preface
To the OEM, VAR, or System Integrator
Thank you for purchasing the high performance Series 87 Enterprise-IV EISA VL-Busmotherboard from
American Megatrends. It is assumed that you have also licensed the rights to use the technical documentation for the
Enterprise-IV. This manual was written for American Megatrends customers who are system integrators, VARs, or
OEMs to assist in the proper installation and operation of the Enterprise-IV motherboard. This manual is not meant
to be read by the computer owner who purchases a computer with the Enterprise-IV 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 Enterprise-IV motherboard fails to operate as described or you are in doubt about a configuration option, please
call technical support at 404-246-8600.
Acknowledgments
This manual was written by Vivek Saxena, Paul Narushoff, and Robert Cheng.

Preface
vi
American Megatrends BBS
The American Megatrends BBS permits OEMs, VARs, and system integrators to access technical information about
American Megatrends motherboard, peripheral card, and BIOS products. Product Engineering Change Notices, Tech
Tips, Technical Notes, and complete technical manuals are available on the BBS.
Data Transmission Rates
The BBS automatically handles modems with data transmission rates from 1,200 to 14,400 bps. If using an HST
modem, call 404-246-8780. If using a non-HST modem, call 404-246-8782.
BBS Phone Numbers
The following table lists the characteristics of the BBS phone numbers. The BBS requires no parity, 8 data bits, and
1 stop bit.
Phone Number Characteristics
404-246-8780 Supports HST and v.42bis.
404-246-8781 Supports HST and v.42bis.
404-246-8782 Dual standard. Can handle 2400 or 9600 bps. Supports v.32bis
and v.42bis. Can handle up to 14,400 baud.
404-246-8783 Supports v.32bis and v.42bis.
Packing Slip
You should have received:
• an Enterprise-IV EISA VLB motherboard,
•the
Enterprise-IV Motherboard User's Guide,
• a diskette containing the American Megatrends ECU and EISA configuration files, and
•the
American Megatrends ECU User's Guide.

Enterprise-IV EISA VLB Motherboard User's Guide
1
Chapter 1
Introduction to VL-Bus
The Series 87 Enterprise-IV EISA Local Bus Motherboard conforms to the VESA® (Video Electronics
Standards Association) VL-Bus® specifications as well as the EISA (Extended Industry Standard
Architecture) specification.
The VL-Bus
The VL-Bus is designed to standardize the hardware interface of peripherals connected to a
microprocessor-level local bus. The VL-Bus Specification is a standard set of interface, architecture,
timings, electrical, and physical specifications that permits all VL-Bus products to be totally
interchangeable.
VL-Bus is Based on 80486 Local Bus Design
The general architecture of the VL-Bus is designed to Intel® 80486 CPU local bus standards with
additional hardware functions that accommodate VL-Bus master devices and facilitate the system I/O bus
interface. The timing specifications allow VL-Bus devices to operate at the full 32-bit 80486 CPU
bandwidth. Both VL-Bus slots on the Enterprise-IV motherboard have bus mastering capability. Six of the
seven EISA expansion slots are EISA (NOT Vl-Bus) bus mastering slots.
EISA and Local Bus Expansion
The American Megatrends Enterprise-IV EISA Local Bus motherboard has seven expansion slots. Six of
these slots are EISA bus mastering slots. One is an EISA non-bus master slot. Two slots are VL-Bus bus
mastering slots. The VL-Bus slots consist of a standard EISA 32-bit slot connector and an inline VL-Bus
connector.

Chapter 1 Introduction to VL-Bus
2
Introduction to VL-Bus, Continued
The following graphic shows the EISA and VL-Bus expansion slots. You can install 16-bit ISA or 32-bit
EISA adapter cards in any expansion slot, including the VL-Bus slots. The VL-Bus expansion slots include
one EISA slot that has both EISA and VL-Bus bus mastering (SLOT 6) slot and one VL-Bus master slot
(SLOT 7) that is an EISA non-bus mastering slot.
EISA or ISA adapter cards have no VL-Bus functionality when installed in a VL-Bus expansion slot.
The current VL-Bus expansion socket specification includes a 16-bit MCA® (Micro Channel Architecture)
expansion socket inline with a standard 32-bit EISA expansion socket connector.
A future VL-bus specification will use a 32-bit MCA connector (a total of 64 bits). The VL-Bus
specification supports 32-bit EISA adapter cards.
The VL-Bus Adapter Cards have a different set of connectors on the bottom of the card and will only fit in
the VL-Bus expansion slots.

Enterprise-IV EISA VLB Motherboard User's Guide
3
Chapter 2
Enterprise-IV Description
Dimensions
The American Megatrends 80486 Enterprise-IV EISA Local Bus motherboard is approximately 8½" by
13", similar in size to a standard Baby AT® motherboard. The mounting hole locations permit the
motherboard to be used with any Baby AT chassis. The height of the components is no more than 1½
inches, but allow 2 inches of clearance for the power supply connectors, as shown below.

Chapter 2 Description
4
Specifications
Processor Type and Speed
Microprocessors can be installed in two sockets: the CPU socket and the Upgrade Socket. The motherboard
supports the following processors:
Processor in ZIF Socket
(Upgrade Socket) PQFP Processor Frequency
Empty 486SX 20, 25, or 33 MHz
Empty 486DX 20, 25, or 33 MHz
486DX empty 25, 33, or 50 MHz
486DX2 empty 25 MHz (50 MHz internal),
33 MHz (66 MHz internal)
486SX 486SX 20 or 25 MHz
P24 empty 25 MHz or 33 MHz
P24T empty 25 MHz (50 MHz internal),
33 MHz (66 MHz internal)
487SX 486SX
(or none) 20, 25, or 33 MHz
Intel Overdrive® (P23T) empty 25 MHz (50 MHz internal),
33 MHz (66 MHz internal)
CPU Sockets
The Enterprise-IV may come with a factory-mounted 486DX or 486SX. It also has a 240-pin PGA ZIF
upgrade processor socket for an Intel 80486DX, 80486SX, 80486DX2, or upgrade processor CPU.
If both the PQFP and ZIF sockets contain CPUs, the CPU in the ZIF socket will be the active CPU.
The Enterprise-IV motherboard also will support future Intel processors.

Enterprise-IV EISA VLB Motherboard User's Guide
5
Specifications, Continued
Programmable Crystal Oscillator
The Enterprise-IV motherboard has a programmable crystal oscillator that supports all possible
motherboard frequencies.
Heat Sink for 50 and 66 MHz CPUs
The Enterprise-IV EISA Local Bus motherboard has a heat sink for all motherboards equipped with a 50
MHz 80486DX or 25 MHz (operates at 50 MHz internally) or 33 MHz (operates at 66 MHz internally)
80486DX2 to help dissipate heat. See page 91 for additional information about heat dissipation.
Processor Speeds
The Enterprise-IV operates at either of two speeds: high or low. High speed is set at time of manufacture to
the processor speed (25, 33, 50, or 66 MHz). A low speed that is approximately the same speed as an
original IBM® AT is simulated by adding extra cycles. The clock speeds can be changed via the <Ctrl>
<Alt> <+> and <Ctrl> <Alt> <-> keychords. These keychords can be changed by the OEM via AMIBCP.
System Memory
The Enterprise-IV EISA VLB motherboard supports up to 256 MB of onboard memory via four banks of
256 KB x 36, 1 MB x 36, 4 MB x 36, or 16 MB x 36 SIMMs. Each SIMM bank consists of four SIMM
slots, a total of 16 SIMM sockets. The 70 ns SIMMs must support fast page mode.

Chapter 2 Description
6
Specifications, Continued
Cache Memory
The 256 KB secondary (external) cache memory uses a write-through or write-back caching algorithm. Up
to 64 MB of system memory is cached. There are zero wait states for cache memory read and write for
motherboards operating at speeds up to 33 MHz. Burst mode is supported. In addition, 80486 processors
have an 8 KB internal cache memory. All of system memory is cached in the 80486 internal cache memory.
Both internal and external cache memory is enabled by pressing <Ctrl> <Alt> <Shift> <+> and disabled by
pressing <Ctrl> <Alt> <Shift> <->
SRAM Type
The Enterprise-IV EISA VLB motherboard uses 15 ns 32 KB x 8 SRAM DIPs for cache memory.
ROM
The Enterprise-IV EISA VLB motherboard has 128 KB of Read Only Memory in an EPROM used for the
system BIOS at E0000h - FFFFFh.
Shadow RAM
AMIBIOS Setup allows you to selectively shadow the 128 KB system BIOS, video BIOS (in 32 KB
increments), or Adaptor ROM BIOS (in 32 KB increments) in ADVANCED CMOS SETUP in AMIBIOS
Setup.
EISA Configuration Utility
The American Megatrends EISA Configuration Utility is provided with the Enterprise-IV EISA VLB
motherboard. A diskette containing two EISA Configuration files (!AMI87A1.CFG and AMI87A1.OVL) is
also supplied.

Enterprise-IV EISA VLB Motherboard User's Guide
7
Specifications, Continued
System BIOS
The Enterprise-IV EISA VLB motherboard uses a customized AMIBIOS system BIOS with a built-in Setup
configuration utility and hard disk drive utilities. Via AMIBIOS Setup, you can configure up to two user-
definable hard disk drive types. You can easily configure systems with no video monitor, keyboard, or
floppy disk drives in STANDARD CMOS SETUP.
CMOS RAM
The Enterprise-IV has 50 bytes of standard ISA CMOS RAM to store system configuration data. ISA
CMOS RAM, the real time clock, and the battery are on the Dallas DS1387 CMOS RAM/RTC chip. The
Enterprise-IV EISA VLB motherboard also includes an additional 4 KB of EISA Extended CMOS RAM.
Built-in Battery
The Enterprise-IV EISA VLB motherboard uses a Dallas DS1387 CMOS RAM chip with a built-in battery.
Math Coprocessor
Enterprise-IV motherboards equipped with an 80486SX support an optional Intel 80487SX math
coprocessor.
Expansion Slots
The Enterprise-IV has seven 32-bit EISA expansion slots. Six of these expansion slots are EISA bus
mastering slots. The other two slots are VL-Bus bus mastering slots. The VL-Bus and EISA slots also can
be used for 16-bit ISA adapter cards.

Chapter 2 Description
8
Specifications, Continued
Seven DMA Channels
The Enterprise-IV has seven DMA channels. In accordance with the EISA specifications, any DMA
channel may be programmed for 8, 16, or 32-bit DMA device size and ISA compatible, type A, type B, or
burst type C modes.
Fifteen Interrupt Levels
The Enterprise-IV has 15 hardware interrupt levels. Of course, NMIs take precedence over the following
hardware interrupts.
Priority Label Typical Interrupt Source
1 IRQ 0 Interval Timer 1, Counter 0 OUT
2IRQ1Keyboard
3-10 IRQ 2 Used internally for IRQ 8 through IRQ 15
3 IRQ 8 Real-TIme-Clock
4 IRQ 9 EISA bus
5 IRQ 10 EISA bus
6 IRQ 11 EISA bus
7 IRQ 12 PS/2 Mouse
8 IRQ 13 Coprocessor Error
9 IRQ 14 EISA bus (Hard disk drive controller)
10 IRQ 15 EISA bus
11 IRQ 3 Onboard serial port or EISA bus
12 IRQ 4 Onboard serial port or EISA bus
13 IRQ 5 Onboard parallel port or EISA bus
14 IRQ 6 Onboard floppy controller or EISA bus
15 IRQ 7 Onboard parallel port or EISA bus
Onboard I/O
The Enterprise-IV has an onboard IDE controller, floppy controller, two serial ports with National
Semiconductor 16450 UARTs, and a parallel port.

Enterprise-IV EISA VLB Motherboard User's Guide
9
Specifications, Continued
Timer Features
The Enterprise-IV has five programmable 16-bit counter/timers.
System Arbiter
The Enterprise-IV has standard EISA arbitration features.
Refresh Generation
The Enterprise-IV has a refresh generation feature.
I/O Capability
The Enterprise-IV accesses 32-, 16-, or 8-bit memory devices and 32-, 16-, or 8-bit I/O devices on both the
VL-Bus and the EISA bus.
I/O Address Space
The Enterprise-IV uses I/O addresses x100h through x3FFh for ISA compatible I/O (x= a "don't care"
character which does not affect mapping location. For example, I/O port addresses 0100h, 1100h, 2100h,
and 3100h map to the same location).
The Enterprise-IV also uses the following EISA I/O port addresses:
•s000h through s0FFh for EISA expansion slot
•s400h through s4FFh for EISA expansion slot
•s800h through s8FFh for EISA expansion slot
•sC00h through sCFFh for EISA expansion slot
(s= EISA bus slot number, the motherboard is always 0)

Chapter 2 Description
10
Specifications, Continued
Memory Range
The Enterprise-IV uses 32-bit memory addresses to access 4 gigabytes of memory address space on the
EISA expansion slots.
I/O Channel Check
The Enterprise-IV supports the use of the I/O channel check to generate NMIs.
I/O Wait State Generation
The Enterprise-IV has an open bus structure (allowing multiple microprocessors to share system resources,
including memory). The Enterprise-IV supports refresh of system memory from channel microprocessors.
Keyboard and Keyboard Lock
The Enterprise-IV has a five-pin IBM AT-compatible DIN connector and has a keyboard lock to prevent
unauthorized access.
PS/2 Mouse
A PS/2 mouse can be used via a cable attached to a 10-pin berg mouse connector mounted next to the
keyboard connector.
Speaker
The Enterprise-IV has a standard speaker attachment.
Real Time Clock
The Enterprise-IV has a standard crystal-controlled AT-type real time clock. The real time clock is included
with ISA CMOS RAM on the Dallas DS1387 chip.

Chapter 3 Installation
20
Chapter 3
Installation
Step Action Turn to
1 Unpack the motherboard Page 20
2 Set switch and jumper options. Page 22
3 Install memory. Page 25
4 Install upgradable processor or math coprocessor. Page Error!
Bookmark not
defined.
5 Install motherboard. Page 30
6 Connect the power supply. Page 32
7 Connect the keyboard. Page 35
8 Connect the mouse. Page 35
9 Connect cables. Page 36
10 Install adapter cards Page 41
11 Perform initial test and configuration. Page 47
Step 1 Unpack the Motherboard
Step Action
1 If the box is damaged, call Technical Support at 404-246-
8600.
2 Perform all unpacking and installation procedures on a
grounded 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.
3 The motherboard is packed in an anti-static bag, and
sandwiched between sheets of sponge. Remove the sponge and
the anti-static bag. Save the original packing material.
4 Place the motherboard on a grounded anti-static surface
component-side up.
5 Inspect the motherboard for damage. Do not apply power if
damaged.
6 Press down on all socketed ICs to verify proper seating.
7 If the motherboard is undamaged, it is ready to be installed.

Enterprise-IV EISA VLB Motherboard User's Guide
21

Chapter 3 Installation
22
Step 2 Set Switch and Jumper Options
CPU and Upgrade Socket
Intel 80486SX, 80486DX, or 8048DX2 CPUs can be inserted in the CPU socket. An Intel 80487SX math coprocessor or
an Upgrade Processor (P23T or P24T) can be inserted in the Upgrade Socket.
SW1
SW1 has two switches. See the graphic on the previous page for the SW1 location. Set SW1 before installation.
Switch Description
DIAG Turns on manufacturing diagnostics. This switch is factory-set to
OFF and should remain OFF.
COL/MONO Sets the video type. It has no effect if an EGA or VGA adapter is
used. It is factory-set to OFF ( for a monochrome display adapter).
Set ON to use a CGA video adapter card.
J15, J16, J43 CPU Select
J15 (a four-pin berg), J16 (a three-pin berg), and J43 ( a two-pin berg) together select the CPU type.
CPU in ZIF
Socket PQFP CPU J43 J15 J16
None 486DX/SX OPEN N/A N/A
P23T,
487SX, or
P24T
486DX/SX SHORT Short 1-2
Short 3-4 Short 2-3
P23T,
487SX, or
P24T
N/A Short 1-2
Short 3-4 Short 2-3
486DX or
486DX2 N/A Short 1-2 Short 3-4 Short 1-2
486DX or
486DX2 486DX/SX SHORT Short 1-2 Short 3-4 Short 1-2
486SX N/A Short 2-3 N/A
486SX 486DX/SX SHORT Short 2-3 N/A