American Megatrends Merlin DP User manual

Merlin DP
Dual Pentium® Pro
PCI ISA Motherboard
User's Guide
MAN – 750
12/10/96

Merlin DP PCI Motherboard User’s Guide
© Copyright 1996 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 and Pentium are registered trademarks of Intel Corporation.
MS – DOS, Microsoft Word, and Microsoft are registered 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.
VESA and DPMS are trademarks of Video Electronics Standards Association.
All other brand and product names are trademarks or registered trademarks of their respective companies.
Revision History
9/25/96 Initial release of preliminary version.
10/22/96 Corrected minor errors in manual.
12/10/96 Added new AMIBIOS Setup options.

Preface
Preface
To the OEM
Thank you for purchasing the high performance American Megatrends Merlin
DP Dual Pentium Pro 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 Merlin DP 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 Merlin DP PCI motherboard. It explains how to assemble a
system based on the Merlin DP 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.

Merlin DP PCI Motherboard User’s Guide
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.
Packing List
You should have received the following:
• a Merlin DP PCI motherboard,
• two serial cables,
• one parallel cable,
• a Warranty Card, and
• the American Megatrends Merlin DP PCI Pentium Pro Motherboard User's
Guide.

Chapter 1 Hardware Installation
1Hardware Installation
Overview
The American Megatrends Merlin DP PCI Pentium Pro ISA motherboard
features include:
• supports two Intel Pentium Pro CPUs operating at 133, 150, 166, 180, or 200
MHz,
• supports up to 512 MB of system memory,
• parity checking or ECC (Error Checking and Correction),
• PCI local bus throughput of 132 megabytes per second,
• three ISA expansion slots, and
• four PCI expansion slots.
ISA DMA or Bus Masters
The Merlin DP Pentium Pro PCI ISA motherboard conforms to the PCI Version
2.1 specification, if the PCI 2.1 Compliance option in Chipset Setup is set to
Enabled. The Version 2.1 PCI specification requires a deterministic latency for
PCI devices.
Computers that use ISA DMA or ISA bus masters will experience longer
access latencies if the PCI 2.1 Compliance Chipset Setup
option is set to Enabled.
AMIBIOS automatically configures the PCI slots. The PCI slots are
synchronous with the CPU clock:
CPU External Clock FrequencyPCI Expansion Slot Frequency
66 MHz 33 MHz
60 MHz 30 MHz
50 MHz 25 MHz
Onboard I/O The Merlin DP 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, and
• a 9 – pin berg mouse connector.

Merlin DP PCI Motherboard User’s Guide
Merlin DP PCI Dimensions
The motherboard is approximately 8.55” by 13”.
Expansion
Slots
0.62"
Keyboard
Connectors
0.85"SIMM
Sockets
1.5"CPUFanand
VoltageRegulators
2"
PowerConnectors
1.5"
13"
8.55"
Warning
This motherboard contains sensitive electronic
components that can be easily damaged by static
electricity. Follow the instructions carefully to ensure
correct installation and to avoid static damage.

Chapter 1 Hardware Installation
Merlin DP PCI Motherboard Layout
J1Floppy
J7
PS/2 MOUSE
J11
KEBD
P2
P1
Megatrends
Megatrends
J22
PCI SLOT 1 PCI SLOT 2 PCI SLOT 3
PCI SLOT 4
BANK0BANK1
RTC/
Battery
J31
J5
CPU
Fan
Pin1isidentifiedby asquarepin
andbyapointedbox on thesilkscreen.
J30
J14 USB2 J13 USB1
J2 Parallel
J32
J33
J35 SPKR
Megatrends
1 2
J26
1 2
J20
J16
Alarm
BIOS
Optional
ROM
J8 SER1
J9 SER2
J10Secondary IDE J12 Primary IDE
J23
J17
J29 J34
J36 KEYLOCK
J3
CPU
Fan
1 2
J4
J6
1 2

Merlin DP PCI Motherboard User’s Guide
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
Step 2 Configure CPU
J16, J17, J26, and J22 select the CPU speeds and voltages for the two CPUs.
Both CPUs are configured to the same speed.
CPU Speed
If using two CPUs with different speed ratings, set the motherboard jumpers to
the lower CPU speed.
CPU Speed J22 J16 J17 J26
150 MHz Short Pins 1 – 2 Open Shorted Short Pins 3 – 4
Short Pins 5 – 6
Short Pins 7 – 8
166 MHz Short Pins 1 – 2 Shorted Open Short Pins3 – 4
Short Pins 5 – 6
Short Pins 7 – 8
180 MHz Short Pins 1 – 2 Open Shorted Short Pins 1 – 2
Short Pins 5 – 6
Short Pins 7 – 8
200 MHz Short Pins 1 – 2 Shorted Open Short Pins 1 – 2
Short Pins 5 – 6
Short Pins 7 – 8
Important
Please contact American Megatrends technical
support at 770 – 246 – 8645 to support a CPU
running at a higher speed.
Cont’d

Merlin DP PCI Motherboard User’s Guide
Step 2 Configure CPU, Continued
CPU Voltage
Each CPU can be independently set to the correct CPU core voltage. The
factory setting for both CPUs is 3.3V. It should not be changed unless the CPU
is rated differently. J6 sets the CPU voltage for the CPU in U13. J4 sets the CPU
voltage for the CPU in U12.
Core CPU Voltage J6 and J7 Setting
3.5V Short Pins 1 – 2
Short Pins 3 – 4
Short Pins 5 – 6
Short Pins 7 – 8
3.4V Short Pins 1 – 2
Short Pins 3 – 4
Short Pins 5 – 6
3.3V (Factory Setting) Short Pins 1 – 2
Short Pins 3 – 4
Short Pins 7 – 8
3.2V Short Pins 1 – 2
Short Pins 3 – 4
3.1V Short Pins 1 – 2
Short Pins 5 – 6
Short Pins 7 – 8
3.0V Short Pins 1 – 2
Short Pins 5 – 6
2.9V Short Pins 1 – 2
Short Pins 7 – 8
2.8V Short Pins 1 – 2
2.7V Short Pins 3 – 4
Short Pins 5 – 6
Short Pins 7 – 8
2.6V Short Pins 3 – 4
Short Pins 5 – 6
2.5V Short Pins 3 – 4
Short Pins 7 – 8
2.4V Short Pins 3 – 4
2.3V Short Pins 5 – 6
Short Pins 7 – 8
2.2V Short Pins 5 – 6
2.1V Short Pins 7 – 8
No Voltage OPEN
Cont’d

Chapter 1 Hardware Installation
Step 2 Configure CPU, Continued
Voltage Regulator
One Voltage Regulator Module is shipped with every Merlin DP motherboard.
You need another VRM if you install two CPUs. You can order VRMs for Intel
Pentium Pro CPUs from:
Manufacturer Part Number AMI Part
Number
VXI Electronics, Inc.
4607 SE International Way
Milwaukie OR 97222
503 – 652 – 7300
Fax: 503 – 786 – 5011
073 – 20674 – 07X MDL – P6 –
V5A124
Connect CPU FanJ3 and J5 (shown below) are two – pin bergs that connect the fan on the CPU
heat sink to the motherboard power. J5 is the CPU fan connector for the CPU in
socket U13. J3 is the CPU fan connector for the CPU in socket U12.
J3
+12VPin1
GND J5
+12VPin1
GND
All Pentium Pro CPUs are shipped with a heat sink and a CPU fan. The wire
from the CPU fan has two leads. The fan cable has a red lead and a black lead.
Connect the Red lead to +12V.
Warning
The red wire from the CPU fan must be connected to Pin 1 of J3
and J5.
Cont’d

Merlin DP PCI Motherboard User’s Guide
Step 2 Configure CPU, Continued
Install CPU
Install the CPU in the ZIF (zero insertion force) socket by performing the
following steps. The CPU socket is near one edge of the motherboard.
Warning
Improper CPU installation can damage the CPU and
the motherboard. You must follow the procedures in
this section exactly as documented. Make sure you
wear an antistatic wristband while installing the
CPU. Follow all prescribed antistatic procedures.
Step Action
1Lift the lever on the ZIF socket. The empty CPU socket looks like this.
2Check for bent pins on the CPU. Gently straighten any bent pins with
pliers. Place the CPU in the middle of the socket, as shown below. Make
sure that pin 1 of the CPU is aligned with pin 1 of the socket. Make sure
you are properly grounded while handling the CPU.

Chapter 1 Hardware Installation
Step Action
3Complete installation by lifting the ZIF lever to the other side of the
socket, as shown below.
PentiumPro

Merlin DP PCI Motherboard User’s Guide
Step 3 Install Memory
System Memory
Four 32 – bit SIMM sockets are on this motherboard.
System memory must be populated one bank at a time. Each bank has two
sockets.
Bank0 includes U11 and U14. Bank1 includes U8 and U9.
Each bank must be populated with the same type of SIMM. If a 4 MB SIMM is
installed in the first socket in Bank0, then the same type of 4 MB SIMM must
be installed in the second Bank0 SIMM socket. The minimum amount of
system memory supported by the Merlin DP PCI is 8 MB. Each socket can hold
one SIMM. You can use:
• 1 MB x 32 (or 36),
• 2 MB x 32 (or 36),
• 4 MB x 32 (or 36),
• 8 MB x 32 (or 36),
• 16 MB x 32 (or 36), or
• 32 MB x 32 (or 36) SIMMs.
The Merlin DP motherboard will support 128 MB SIMMs when they become
available, permitting up to 512 MB of system memory to be installed on the
motherboard.
Fast Page Mode, EDO, and Burst EDO SIMMs cannot be mixed. The
motherboard supports SIMMs operating at 50, 60, or 70 ns RAS access time.
Set the Chipset Setup DRAM Speed option correctly.
Memory Display
System memory is reported by AMIBIOS as it boots and again when the
AMIBIOS System Configuration Screen is displayed just before the operating
system boots. The memory displayed by AMIBIOS on the System
Configuration Screen is 384 KB less than the total memory installed.
Cont’d

Chapter 1 Hardware Installation
Step 3 Install Memory, Continued
Select SIMMs
SIMMs must meet the following specifications:
Parameter Specification
Page Mode FAST
Refresh CAS before RAS
tCAC ≤20 ns
tRAC ≤80 ns
tAA ≤45 ns
tRP 70 ns
tCPA ≤45 ns
SIMM Part Numbers
Type Manufacturer Part Number
1 MB x 36 Micron MT12D136M – 7
“Mitsubishi MH1M36ADJ – 7
“PNY P361000 – 70
“Motorola MCM36100AS – 70
“Oki MSC2355 – 70YS12
“Samsung KMM5361000AV – 7
2 MB x 36 PNY P362000 – 70
“Samsung EMM53620036 – 70
4 MB x 36 Micron MT12D436M – 7
“Mitsubishi MH4M36SAJ – 7
“Motorola MCM36400S – 70
“PNY P364000 – 70
“Samsung KMM5364100 – 7
8 MB x 36 Motorola MCM36800S – 70
“PNY P368000 – 707
“Samsung KMM5368100 – 7
16 MB x 36 Samsung KMM53616000AKG – 6
Installing SIMMs
The four SIMM sockets on the motherboard can be filled with either 1 MB x 32
(or 36), 2 MB x 32 (or 36), 4 MB x 32 (or 36), 8 MB x 32 (or 36), or 16 MB x 32 (or
36) SIMMs. Place the motherboard on an anti – static mat. With the component
side of the SIMM facing you, firmly push the SIMM into the socket at an
angle, then push it up. When properly inserted, the SIMM clicks into place as
the latching pins engage.

Merlin DP PCI Motherboard User’s Guide
Step 4 Install the Motherboard
The motherboard mounting hole pattern is the same as the mounting hole
pattern on the standard baby AT motherboard. Standoffs and mounting screws
are not supplied with the motherboard. The chassis manufacturer should
supply these parts.
Step Action
1Place the chassis on an anti – static mat. Connect the chassis
to ground to avoid static damage during installation.
Connect an alligator clip with a wire lead to any unpainted
part of the chassis. Ground the other end of the lead at the
same point as the mat and the wristband.
2Rotate the chassis so the front is to the right, and the rear is
to the left. The side facing you is where the motherboard is
mounted. The power supply is mounted at the far end of the
chassis.
3Hold the motherboard, component – side up, with the edge
with the SIMM sockets toward you and the edge with the
power supply connector away from you. The keyboard,
mouse, and video connectors should be to the left.
4Carefully slide the motherboard into the chassis. Make
certain the edge connectors fit the ports in the rear of the
chassis. The motherboard should rest level with the chassis.
5Place the mounting screws in the holes provided and tighten
them. If necessary, shift the motherboard slightly to align the
mounting holes on the motherboard with the holes on the
chassis.
Warning
If using metallic screws, make sure you use them only
in the plated mounting holes.
If using metallic screws, make sure the head of the
screw fits completely inside the plated mounting holes.

Chapter 1 Hardware Installation
Step 5 Attach Cables
Connectors
The Merlin DP PCI motherboard includes many connectors. Connection
instructions, illustrations of connectors, and pinouts are supplied in the
following screens.
Cable Connector Ends
When connecting chassis connectors to the motherboard, make sure to
connect the correct connector end. Most connector wires are color – coded.
Match the color of the wires leaving the switch or LED to the same pin on the
connector end. There may be more than one connector with the same color –
coded wires. If so, follow the wire to the switch or LED. All motherboard
components are outlined by a white rectangular box with a broad arrow at one
end. Pin 1 is always at the arrow end of the white outlined box.
Connect Power Supply
The power supply should match the physical configuration of the chassis.
Make sure the power switch is off before assembly. Before attaching all
components, make sure the proper voltage has been selected. Power supplies
often can run on a wide range of voltages and must be set (usually via a
switch) to the proper range. Use at least a 250 watt power supply, which should
have built – in filters to suppress radiated emissions.
Connect Power Cables
Attach the power supply cables to the power connector (P1 and P2) on the
motherboard. AT – compatible power supplies have two six – pin connectors,
attached as shown below. The six – pin connector on the power cable with
three red wires and two black wires is attached to P2. The other connector on
the end of the power cable is attached to P1.
P1
P2
BLACK
BLACK
W
HITE
RED
RED
RED
ORANGE
RED
YELLOW
B
LACK
BLA
CK
BLUE
Cont’d

Merlin DP PCI Motherboard User’s Guide
Step 5 Attach Cables, Continued
Power Connector Keys
The power connectors are keyed to prevent incorrect installation. The keys on
the connector must be cut to fit on some power supplies, as shown below.
Pin1Pin1
P1 Pinout
Pin Description
1Power Good (Orange wire) (Not used)
2VCC (Red wire)
3+12 Volts (Yellow wire)
4– 12 Volts (Blue wire)
5Ground (Black wire)
6Ground (Black wire)
P2 Pinout
Pin Description
1Ground (Black wire)
2Ground (Black wire)
3– 5 Volts (White wire)
4VCC (Red wire)
5VCC (Red wire)
6VCC (Red wire)
Cont’d

Chapter 1 Hardware Installation
Step 5 Attach Cables, Continued
J11 Keyboard Connector
The keyboard connector is a 6 – pin DIN socket. The pinout is shown below.
Pin Assignments
1Keyboard clock
2Keyboard data
3, 6 Not used
4Ground
5VCC
Connect Mouse Cable
The mouse connector (J7 ) is a 10 – pin berg. The mouse cable is the same as
the serial cable in the motherboard. Two serial cables are shipped with the
motherboard. Use one of these cables for the mouse, or make your own cable.
The pinout is:
Pin Description Pin Description
1Mouse Clock 2N/C
3N/C 4N/C
5N/C 6VCC
7N/C 8Mouse Data
9Ground 10 N/C
PS/2 Mouse IRQ
J23 is a three – pin berg that enables the PS/2 mouse interrupt (IRQ12). Short
Pins 1 – 2 of J23 to enable IRQ12 as the PS/2 mouse interrupt. You should
always short Pins 1 – 2 of J23 to enable the PS/2 mouse interrupt. The only
reason you would ever have to short Pins 2 – 3 of J23 is if you wanted an
adapter card on the ISA bus to use IRQ12. You would then have to set the
Mouse Support option in Advanced Setup to Disabled.
J23Pins1-2Shorted
IRQ12usedforPS/2Mouse
Cont’d

Merlin DP PCI Motherboard User’s Guide
Step 5 Attach Cables, Continued
J29 Green PC Power
J29 is a two – pin berg that connects to a Green PC power supply. When the
computer enters a power conserving state, a signal is sent from this berg to the
power supply to permit the power supply to switch to a low power, high –
efficiency mode. The + on Pin 2 identifies the positive connector.
J32 Reset Switch Connector
J32 is a two – pin single – inline berg that is attached via a cable to an
externally – mounted reset switch. When the reset switch is pressed, the
system performs a hard reset. Pin 1 is ground and Pin 2 is Hard Reset.
J35 Speaker Connector
J35 is a four – pin single – inline berg that is optionally attached via a cable to a
standard system speaker. AMIBIOS signals hardware problems through the
speaker. Pin 1 on the motherboard is identified by the arrow on the white box
around the berg. The Merlin DP PCI motherboard also has a built – in speaker
mounted on the motherboard.
Pin Description
1Data Out
2Key
3N/C
4VCC
Cont’d