
The material in this manual is for information only and is subject to change without
IBM, IBM PC/XT/AT, PC-DOS, MS-DOS, OS/2, INTEL, AMI ARE TH
OR REGISTERED TRADEMARKS OF THEIR RESPECTIV

RADIO FREQUENCY INTERFERENCE STATEMENT
rates and uses radio frequency energy and
nd used properly, that is, in strict accordance
the manufacturer's instructions, may cause interferenc
with radio and television reception.
equipment does cause interference to radio or T
which can be determined by turning the equipmen
on, the user is encouraged to try to correct th
interference by one or more of the following measures:
Reorient the receiving antenna.
Relocate the computer away from the receiver.
Move the computer away from the receiver.
into a different outlet so that computer
and receiver are on different branch circuits.
ard slot covers are in place when no card is
that card mounting screws, attachment connecto
screws, and ground wires are tightly secured.
are used with this system, it is suggested to
shielded, grounded cables, with in-line filters i
If necessary, the user should consult the dealer servic
representative for additional suggestions.
nufacturer is not responsible for any radio or T
caused by unauthorized modifications to thi
equipment. It is the responsibility of the user to correct such

components are sensitive to dust and dirt
Do inspect and clean the computer system regularly.
r whenever you install or remove any
memory module and add-on card. Befor
on the power, make sure that all th
memory modules and add-on cards ar
it for a minute. The system BIOS
ing through a self-test during this period an
the screen. After the self-test, the
BIOS will initialize the display adaptor an
The SIMM sockets are fragil
e device. Do not force the
SIMM modules into the sockets. It may break th

s information about the installation
intenance of HIPPO COM motherboard. In-dept
explanations of the functions of
this motherboard are provided.
In the appendix, the system BIOS setup is explained.
this manual is only for reference and is
intended to provide the basic informatio
There are also technical informatio
n for hardware and software
In this manual, there are 4 chapters. Chapter
contains a brief introduction and sp
apter 2, the functions of HIPPO COM
plained. It also outlines many advanced features of the
nd the system architecture. Chapter 3 explains th
of coprocessor, DRAM modules and jumpers
Technical information is provided in the Chapter 4.
System BIOS is described in the attached BIO

System Board Jumper Setting
Direct Memory Access (DMA)
Real Time Clock and CMOS RAM
Real Time Clock Information

OPERATION AND MAINTENANCE
Cleaning The `Golden Finger'
SUMMERY OF JUMPER SETTING

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to be a powerful platform for
software available now and in the future. I
the most powerful microprocessor 80486 whic
combines CPU, numeric coprocesso
r and internal cache memory
a single chip. HIPPO COM fully takes advantage of th
80486 and provides high performance, reliability and
compatibility to the user.
Fast A20 gate and fast reset genera
improve the performance of
advanced operation system and
expanded memory managers.
atibility and reliability are important issues. I/O
is compatible to standard AT bus and any periphera

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X, 80486DX2, 80486SX or 80487SX CPU
Compatible to standard AT bus
Shadow RAM for system and video BIOS
Page mode and hidden refresh
SIMM sockets for 256KB, 1MB or 4MB modules

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8KB four way set associative internal cache
System Support Functions :
8-Channel DMA (Direct Memory Access)
CMOS RAM for system configuration
Real time clock with battery back-up
Fast A20 gate and fast reset
External battery connector

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of HIPPO COM comes from 80486. 80486
is the state-of-art microprocessor which m
on a single chip for advanced applications an
operation systems. Fabrica
ting with the 1um process, this CPU
ists of more than one million transistors. With such high
density, this CPU incorporates as many
itself the most powerful microprocessor.
is a 32-bit microprocessor with 32-bit externa
data bus and 32-bit external address bus. It not only contai
central processing unit, but also integrates a numeri
and a four-way set associate cache memory. It i
binary compatible with 80386 and 80387. All existin
software for PC XT/AT can be used on HI
w internal architecture, the performance of 80486
is two to four times of 80386.
emory can improve the overall performance of
a computer system. Nevertheless, if the cache memory i
from CPU, CPU still needs to fetch code and dat
through external bus. Tha
t means the data transfer rate should
not be too fast so that the external devices ar
he CPU. In 80486, the cache controller and cach
are integrated into the chip. Most of the operation
can be carried out inside the CPU, which reduces the bu
operations on external da
ta and address bus and thus speeds up

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The cache memory is a 8K bytes, 16 bytes line size
set associative configuration. The hit rate of thi
is much better than 32K bytes two-way se
external cache because a four-way set associativ
hitecture provides better performance in a multitasking and
multi-processor environment.
Bus snooping feature keeps the cache mem
with the main memory. Whe
n an external processor overwrites
the main memory, the corresponding data in the
be invalidated and will be fetched
from main memory when CPU reads this data.
ead miss occurs, the CPU will initiate a burs
d operation. In burst mode read operation, CP
four successive read operations each of which take
ycle. Total 128 bits data are fetched into the CPU's
cache. Since burst mode read operation is very fast
the traffic of the CPU bus is greatly reduced and the bus i
available to other bus masters, such as DMA controller.
128 bits data into CPU will
In order to reduce the delay, the intern
al cache controller works
fetches the data needed by CPU for the
eration and the CPU read cycle is terminated. Then
other data are read into the internal cache memory whil
is doing something else. This arrangement permits th
CPU to run at zero wait state.

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iminating the access to external bus, operation
internal cache can be completed in a single cycle
at least needs two cycles for an operation. To furthe
the rate of data transfer inside the CPU, the interna
bus of the cache memory is inc
reased to 128 bits, which is four
l bus. Since, in most of the time, the CPU
is using the internal cache, the large bus size substantiall
improves the overall performance.
the CPU writes data to the main memory, th
data is first stored in a write buffer. There are four writ
rnal bus is idle, data will be sent to the
mory. If all buffers are filled, it can start writ
in burst mode. Since the internal cache is update
U need not suspend its operation and there
to wait for the external device to update the mai
ften-used instructions are executed in a cloc
d some instructions are modified to take fewer cycle
than in 80386. On the contrary, 80386 may take two to three
cycles for the same instruction. The CPU contains a
instruction pipeline structure and a 32-byte cod
queue to speed up the execution.
80486 includes all the functions
ted software and operation systems which are
employed now. It is able to operate in real mode
protected mode and virtual 8086 mode.

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memory management unit provides a flexibl
scheme for the next generation operation system
current operation and manipulating huge data
e can be accomplished with excellent performance. Paging
allow powerful operating system to
virtual memory. Each segment is divided int
pages which are 4K bytes per page. Page mechanis
parent to software and allows software to address 6
64KB segment boundary which is
er of 8088 and 80286 is removed and the segmen
length can be increased up to 4GB.
The demand for sophisticated, number-crunchin
and business applications has rapidly increased i
years. In the past, microprocessor features an intege
Logic Unit which only handles simple intege
ions such as addition and multiplication. Floating-point
which are actually utilized by applications must b
accomplished through software routines.
et the demand of floating-point calculation,
coprocessor is necessary. However, an externa
coprocessor has been found to be the bottleneck o
integrates the coprocessor on chip and thus the dat
is eliminated. The on-chip coprocessor
is compatible with 80387.
It works parallel with other units in
the CPU, which results in a better performance of numeri

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be installed on board. So 8
dules may be installed on your system and th
maximum memory size is up
to 32MB, 256KB, 1MB and 4MB
SIMM modules are supported. The DRAM should b
fast-page mode DRAM with staggered refresh capability.
memory system provides a flexible memor
Several combinations of DRAM types ar
The DRAM type and the memory size ar
automatically detected by t
he system BIOS. So, you may easily
change the configuration of the system.
The memory controller system supports fast
page mode. The memory is div
ided into pages with equal size.
memory accesses within the same page need no
wait state. Furthermore, a burst line fill mode i
implemented. In case of a read miss of cach
l be fetched from main memory to cache memory
page mode operation will speed up the line fil
enhance the system performance, shadow RA
supported. In shadow RAM mode, system BIOS an
video BIOS contained in low speed memory such as EPRO
copied into DRAM. Improvement is significant
because access to DRAM is mush faster than ROM.

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y refresh logic is redesigned to improve the
system performance and power consumption. In the origina
design, the memory refresh operation will suspend th
operation because it has to access the main memory. I
high speed system like HIPPO COM, the CPU indeed ca
a large amount of operations in the memory refres
By implementing hidden refresh method, the refres
rations for expansion card on the AT bus and for the main
To be compatible, the refresh operation
bus will not be changed. But the refresh operation for
l be carried out individually and will be done
ere is no access to main memory. Furthermore, th
quency of the main memory refresh operation may be set to
l types of DRAM can be used in `normal'
When 'slow' mode is selected, the availability of mai
memory is increased but the
refresh period of DRAM should be
Since the refresh period of DRAM from differen
manufacturers may vary, consult your dealer for detail.

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are many PC designs with a special feature
It is intended to speed up the protected
switching operation which is done by the slow spee
controller in the original PC design. However, thi
often causes compatibility problem because they us
hardware logic design to bypass the keyboar
Thus, the BIOS is needed to be modified to tak
advantage of it. An application without
In HIPPO COM, there are some logic designs in th
he keyboard controller. An application can
in the usual way to send commands to keyboar
but these commands are in fact interpreted by th
The protected mode switching operation is muc
There will be no potential problem since modificatio
of software is not needed.

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Important Note : Turn off the power before installing or replacing any
HIPPO COM has eight sockets on board for SIM
Whenever you add memory to the motherboard
install four modules at the
same time. Also make sure that the
on the modules face towards the slot for memor
expansion board. The modules should be l
Please check carefully befo
re turning on the power. Otherwise,
the system will not work properly.
To install a module, the m
odule edge is angled into the
contact and then the module is pivoted into position
latches will secure it. If the module edge is
tely inserted into the socket, it cannot be pivoted to
ertical position and should be dragged out and re
inserted again. Do not force the mod
ule into the SIMM socket.
It will damage the locking latches.
ocked by the locking latches of
the sockets firmly. Please check car
efully before turning on the
power. Otherwise, the system will not work properly.

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the BIOS reports an memory error or parity error
out the modules and insert them again. If the lockin
re damaged, contact your dealer to replace the socket.
The configuration of the memory is very flexi
are several combinations of DRAM types you may consider
256KB, 1MB or 4MB SIMM are accepta
can be equipped with fewer memory and lat
be installed when upgrading the system. There are two banks
DRAM on the motherboard and another two banks on
expansion board. The memory size is detecte
automatically by system BIOS and indic
umper is needed to be set for the memory size
mine what DRAM speed rating should be used
on the system speed and wait state. The highes
omplished by using zero wait state, but high
speed DRAM has to be used. If
zero wait state is selected, fast
M is needed. The wait state setting is applied
Therefore make sure to install DRAM
he same speed rating, or accommodate the wait stat
setting to the slow DRAM type.

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of the shadow RAM function, the 384K
between 640KB to 1MB can not accessed. So, th
size found by the system BIOS is not equal to th
actual memory size. For example, when there i
the BIOS will show 3712KB.

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speed can be controlled by
switch. To change the speed by keyboard, use
P2 to the turbo switch of the case and P4 t
turbo LED of the case. When the turbo mode
the turbo LED of the case will be turned on.
the system speed is set to be slow by turb
switch, it cannot be changed by the keyboard, and vice versa.

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SYSTEM BOARD JUMPER SETTING
There are several options which
the 'System Speed' setting matched with

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Under typical conditions, these connectors should b
to the indicators and switches of the system unit
functions of connectors on the motherboard are liste
Harddisk activity LED connector
Power LED & Keylock connector
Floppy Diskette Drive connector
Primary Serial Port cable connector
Secondary Serial Port cable connector
Parallel Printer Port cable connector
Game Port cable connector
External Battery connector

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Pin assignment of the connector are illustrated a
P1 - Hardware Reset Connector
P2 - Turbo Switch Connector

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P5 - Power LED & Ext-Lock Connector

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P13-P14 - Power Supply Connector

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P15 - External Battery Connector
P16 - Cooling Fan connector

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This section provides technical information abou
intended for advanced users interested in
the basic design and operation of HIPPO COM.

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I/O Address Map on System Board
I/O address hex 000 to 0FF are
Interrupt Controller 1, 8259, Master
(non-maskable interrupt) mask
DMA Page Register, 74LS612
Interrupt Controller 2, 8259
Clear Math Coprocessor Busy

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dress hex 100 to 3FF are available on the I/
Monochrome Display and Printer Adapter
Color Graphics Monitor Adapter

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O COM has three programmable timer/counter
by Headland chipset and they are defined a

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Channel 1 is programmed to generate a 15-micro-second period signal.
The 8254 Timer/Counters are treated by syste
programs as an arrangement of four progra
Three are treated as counters and the fourth is
control register for mode programming.

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levels of system interrupts are provided o
PO COM. The following shows the interrupt-leve
assignments in decreasing priority.
Real-time Clock Interrupt
*,
*,

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DIRECT MEMORY ACCESS (DMA)
HIPPO COM supports seven DMA channels.
Floppy Disk (8 bit transfer)
Cascade for DMA Controller 1

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The following shows the addresses for the
REAL TIME CLOCK AND CMOS RAM
Real time clock and CMOS RAM are contained o
Real time clock provides the system date and time
information. Both are backed up by
and will not lose information after power off. Th
following page shows the CMOS RAM Address Map.

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* Real-time clock information
Low expansion memory byte
High expansion memory byte
* Low expansion memory byte
* High expansion memory byte

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REAL TIME CLOCK INFORMATION
escribes real-time clock bytes and
specifies their addresses.

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HIPPO COM provides four 16-bit slots.
The I/O channel supports:
I/O address space from hex 100 to hex 3FF
Selection of data access (either 8 or 16 bit)
24 bit memory addresses (16MB)

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lowing figure shows the pin numbering for I/
channel connectors (A-side and B-side).

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lowing figure shows the pin numbering for I/
channel connectors (C-side and D-side).

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ummarize pin assignments for the

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Operation and Maintenance
_______________________________
When installing or removing any add-on card, DRA
or coprocessor, you should discharge the stati
on your body. Static electricity is dangerous t
device and can build-up on your body. When yo
touch the add-on card or motherboard, it is li
To discharge the static electricity, touch the metal o
computer. When handling the add-on card, don't contact
the components on the cards or t
heir "golden finger". Hold the
many high-speed components
y will generate heat during operation. Other add-o
ds and hard disk drive can also produce a lot of heat. The
the computer system may be very high. In
keep the system running stably, the temperature must
be kept at a low level. A easy way to do this is to keep th
cool air circulating inside
the case. The power supply contains
n to blow air out of the case. If you find that th
is still very high, it would be better to instal
fan inside the case. Using a larger case i
if there are a number of add-on cards and dis

OPERATION AND MAINTENANCE
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CLEANING THE "GOLDEN FINGER"
n add-on card to the motherboard,
that there is no dirt on the "golden finger" of th
ard. If not, the contact between the "golden finger
the slot may be poor and thus the add-on card may no
work properly. Use a pencil erase
r to clean the "golden finger"
puter system should be kept clean. Dust an
harmful to electronic devices. To prevent dust fro
on the mother-board, installing all mountin
f the case. Regularly examine your system,
necessary, vacuum the interior of the system with

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