DFI 486-OCV Plus User manual
486-OCV Plus
System Board
User’s Manual
- D21840429 -
vCopyright 1994, by DFI Inc.
All rights reserved.
No part of this document may be copied or reproduced
in any form or by any means without the prior written
consent of DFI, Inc.
DFI, Inc. makes no warranties with respect to this
documentation and disclaims any implied warranties of
merchantability, quality, or fitness for any particular
purpose. The information in this document is subject to
change without notice. DFI, Inc. reserves the right to
make revisions to this publication and to make changes
to any and/or all parts of its content, at any time,
without obligation to notify any person or entity of such
changes. Further, DFI, Inc. assumes no responsibility
for any errors that may appear in this document.
DFI is a registered trademark, and 486-OCV Plus is a
trademark of Diamond Flower, Inc. All other product
names mentioned are trademarks or registered trade-
marks of their respective companies.
v Table of Contentsv
Introduction .................................................................................
Features and Specifications .................................................
Installation Overview .................................................................
Preparing the Area ................................................................
Handling the System Board ..................................................
Tips in Handling the System Board ...............................
Hardware Installation .............................................................
Memory Installation .........................................................
Installing the Modules ..............................................
Board Configuration ........................................................
Jumper Settings .......................................................
Jumper Settings for VL-Bus Add-On Board .....
Jumper Settings of Internal/External/CMOS
Clean, Display Type and Diagnostic/
Password Clear ..................................................
Cache Configuration ................................................
Jumper Settings for Cache Memory .................
CPU Installation and Upgrade .......................................
CPU Configuration ..................................................
Jumper Settings for CPUs .................................
Installing Upgrade CPUs ........................................
Installing the System Board ..................................................
Initial Setup Program .................................................................
AMI BIOS Setup Utilities .......................................................
Standard CMOS Setup ..................................................
Advanced CMOS Setup .................................................
Auto Configuration with BIOS Defaults .........................
Auto Configuration with Power-on Defaults ..................
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Change Password .........................................................
Auto Detect Hard Disk ..................................................
Hard Disk Utility .............................................................
Write to CMOS and Exit ................................................
Do not write to CMOS and Exit ....................................
Troubleshooting Checklist ......................................................
Appendix A: Types of Modules ..............................................
Appendix B: System Error Report .........................................
Appendix C: Memory & I/O Maps ...........................................
Appendix D: 16-Bit ISA I/O Pin Assignments .......................
Appendix E: VL-Bus I/O Pin Assignments ...........................
Appendix F: System Overview ...............................................
Appendix G: Connector Pin Assignments ............................
Appendix H: AMI BIOS Hard Disk Table ...............................
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486-OCV Plus
vIntroduction
The 486-OCV Plus system board is designed so that it
may be equipped with Intel's 80486DX, 80486DX2,
80486SX, and 80486 OverDriveTM Processors which can
run from speeds of 25MHz to 66MHz. It may also use
a PentiumTM OverDrive Processor running at 50MHz or
66MHz. This Pentium-based system board is twice as
fast as the 80486DX-33 and accommodates almost all of
the existing programs designed for 386 or 486-based
systems. The system board also supports a Cyrix or
AMD 486DX CPU running at 40MHz.
The 486-OCV Plus is a jumperless-upgrade board
allowing you to easily upgrade your CPU from a 486SX
to 486DX or DX2 for example, without altering any
jumpers. However, if you change your CPU speed from
25MHz to 33MHz, 40MHz or 50MHz, or change a
Cyrix CPU to an Intel or AMD CPU, you may have to
alter a few jumpers.
The 486-OCV Plus is equipped with a Zero Insertion
Force socket to make upgrading your CPU easy. It also
supports an optional Flash EPROM. Flash EPROM is a
memory chip for the storage of BIOS which can be
erased in bulk or modified using a software utility.
The 486-OCV Plus system board is also equipped with
two VESA compliant local bus slots. The VL-Bus of
the 486-OCV Plus system board operates at the same
frequency (up to 40MHz) and phase as the CPU, sup-
porting all DMA and system I/O bus mastering cycles.
Introduction u1-1
PentiumTM OverDrive Ready System Board
The 486-OCV Plus uses 256Kx36, 512Kx36, 1Mx36,
2Mx36, 4Mx36 and 8Mx36 HSIM modules with speeds
of at least 80ns. The memory can be configured to
twenty-one different sizes from 1MB to 64MB. The
system is equipped with two 32-bit VESA VL-Bus and
eight 16-bit ISA expansion slots.
Features and Specifications
•Intel 80486DX running at 33/40/50MHz,
80486DX2 running at 50/66MHz, 80486
OverDriveTM Processor, PentiumTM OverDrive
Processor running at 50/66MHz, or 80486SX
running at 25/33MHz
Cyrix or AMD 486DX running at 40MHz
•Uses AMI BIOS: 27512-20 (1)
•Uses OPTi 82C499 chip set
•Cache organization: direct map, write back and bank
interleave
•Supports 64K, 128K and 256K cache sizes
•Memory configurable from 1MB to 64MB
•Uses 256Kx36, 1Mx36 and 4Mx36 HSIMM
Uses 512Kx36, 2Mx36 and 8Mx36 (for Banks 0 and
2 only)
•Supports memory with parity check
•8MHz bus clock
•Software programmable cache and DRAM wait states
•Supports system BIOS and Video BIOS Shadow
RAM function
•Supports sixteen edge triggered interrupts
•Hidden refresh or slow refresh supported
•Optional Flash memory BIOS supported
•Supports PentiumTM OverDrive Processor Zero
Insertion Force socket
•Supports one PS/2 mouse port
•An optional diagnostic LCD port
1-2 uIntroduction
486-OCV Plus
•Supports VESA VL-Bus devices (2 VESA Master/
Slave)
ISA DMA Master access to local device
Local Master access to an ISA device
Fully compatible with VESA VL-Bus rev. 1.0
•Two 32-bit VL-Bus and eight 16-bit ISA slots
•Maximum card length
Full-length cards in all VL-Bus slots and in three
ISA slots
9.75" cards in three ISA slots
•Four layer PCB
•Baby AT size
•Operating temperature: 0oC - 40oC
•One year limited warranty
Warning:
If your 486-OCV Plus system board is using a 486DX
50 CPU, we recommend that you do not install any
VL-Bus devices. The VL-Bus connectors, compliant
with VESA VL-Bus standard rev. 1.0, limit the speed of
a VL-Bus device operating across the connector
(e.g. an add-on board) to 40MHz.
The table below, based on the VESA VL-Bus
specification, shows the recommended number of
installed VL-Bus devices at various CPU speeds. This
table is only a recommendation, not a requirement. Any
VL-Bus add-on board must correspond with the CPU
speed, whether it is buffered or unbuffered.
CPU Speed Unbuffered Buffered
<= 33MHz 2 slots/2 devices 3 slots/3 devices
40MHz 1 slot/2 devices not recommended
>= 50MHz 0 slot/2 devices not recommended
Introduction u1-3
PentiumTM OverDrive Ready System Board
vInstallation Overview
This chapter summarizes the steps in installing the
486-OCV Plus system board into your system unit. It
also includes a description of the area in which you must
work and directions for memory installation. Before
installing the system board, obtain the memory you plan
to install.
Preparing the Area
Before unpacking the system board, make sure the
location you have selected is relatively free of dust and
static. Excessive exposure to dust, static electricity,
direct sunlight, excessive humidity, extreme cold and
water can damage the operational capabilities of your
system board. Avoid soft surfaces such as beds and
carpeted floors which can hinder air circulation. These
areas also attract static electricity which can damage
some circuits on your system board.
Be sure that the power source has a properly grounded,
three-pronged socket. It is essential that the power
connection be properly grounded for correct functioning
of your system board. For further protection, we rec-
ommend that you use a surge protection socket. This
will protect the system board from damage that may
result from a power surge on the line.
Move items that generate magnetic fields away from
your system board, since magnetic fields can also dam-
age your system board. Once you have selected the
ideal location, unpack the 486-OCV Plus system board
carefully.
2-1 uInstallationOverview
486-OCV Plus
Handling the System Board
It is quite easy to inadvertently damage your system
board even before installing it to your system unit.
Static electrical discharge can damage computer compo-
nents without causing any signs of physical damage. You
must take extra care in handling the system board to
ensure that no static build-up is present.
Tips in Handling the System Board
1) To prevent electrostatic build-up, leave the board in
its anti-static bag until you are ready to install it.
2) Wear an antistatic wriststrap.
3) Do all preparation work on a static-free surface with
components facing up.
4) Hold the system board by its edges only. Be careful
not to touch any of the components, contacts or
connections, especially gold contacts on the board.
5) Avoid touching the pins or contacts on all modules
and connectors. Hold modules and connectors by
their ends.
Hardware Installation
Memory Installation
The 486-OCV Plus system board can support 1MB to
64MB of memory using HSIMMs. HSIMM is an
acronym for High Density Single In-line Memory Mod-
ule.
InstallationOverview u2-2
PentiumTM OverDrive Ready System Board
An HSIMM consists of several RAM chips soldered
onto a small circuit board. An HSIMM connects to the
system board via a 72-pin card-edge connector.
The HSIMM sockets are divided into four banks on the
system board. The 486-OCV Plus system board uses
256Kx36, 512Kx36, 1Mx36, 2Mx36, 4Mx36 and 8Mx36
HSIM modules.
Note:
The 8Mx36 HSIM module must be the standard size
module. Mechanical problem may occur if a longer
size of module is installed.
You will need 1 to 4 pieces of HSIM modules, depend-
ing on the amount of memory you intend to install.
Your system board can be configured with 1MB, 2MB,
4MB, 5MB, 6MB, 8MB, 9MB, 12MB, 13MB, 16MB,
18MB, 20MB, 24MB, 28MB, 32MB, 34MB, 36MB,
40MB, 48MB, 52MB or 64MB of onboard memory.
To install the HSIM modules, first populate Bank 0, then
Bank 1 and so on. Failure to do so will cause the
system board to work improperly.
The following table summarizes the bank locations and
modules needed for the corresponding memory sizes.
Each bank consists of 1 HSIMM socket.
2-3 uInstallationOverview
Table of contents
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