Abit IT5A User Manual

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Part No : MN-112-2A0-01 Rev: 1.00

Table of Contents

Chapter 1 Introduction of IT5A Features

l Specifications.............................................................................1-2

l Layout diagram.......................................................................... 1-4

l System block diagram................................................................1-5

Chapter 2 Installing the Mainboard

¬ Installing the Mainboard to the Casing.......................................2-3

- Standard External Connectors....................................................2-4

® Jumpers and Switches................................................................2-9

¯ Presentation and Installation of the CPU..................................2-10

° Installing System Memory

Chapter 3 Introduction of BIOS

¬ Standard CMOS Setup Menu.....................................................3-4

- BIOS Features Setup Menu ....................................................... 3-6

® Chipset Features Setup Menu................................................... 3-12

¯ Power Management Setup Menu .............................................3-14

° PCI & Onboard I/O Setup .......................................................3-19

± Load BIOS Defaults ................................................................3-24

² Load Setup Defaults................................................................ 3-24

³ Password Setting.....................................................................3-25

´ IDE HDD Auto Detection .......................................................3-26

¡i

DRAM Memory

¡j

.. 2-17

Appendix A Quick Installation

Appendix B Intel Pentium CPUs

Appendix C AMD-K5.K6 CPUs

Appendix D Cyrix / IBM 6x86 CPUs

Appendix E General Discussion about HDD Installation

Appendix F Flash BIOS User Instructions

Appendix G Installation of AGP driver

Appendix H Installation of IDE Bus Master Driver

Appendix I Technical Support

Introduction of IT5A Features

1- 1

Chapter 1 Introduction of IT5A Features

The IT5A has been especially designed for File server, Workstation and Professional

users. It can support a wide range of processors, including Intel CPUs (P54C) and Intel
CPUs with MMX (P55C), as well as all AMD-K5/K6/K6 3D and Cyrix 6x86MX CPUs. It
also takes into account, other future CPUs.

The IT5A uses ALi Aladdin V ( M1541 / M1543 ) chipsets, and has 512K Level-2

Pipeline Burst SRAM on board. This mainboard is designed for use at 100 MHz Front Side
Bus speeds. It also supports the latest AGP technology.

Two 168-pin DIMM ( Dual In-Line Memory Module ) slots meet the requirements for

all memory configurations required by high level computing. The 168-pin DIMM slots
support EDO ( Extended Data Out ) DRAM and Synchronous DRAM ( SDRAM ) as a
memory standard for next generation 64-bit systems.

The IT5A also provides two Universal Serial Bus (USB) ports and meets the

Concurrent PCI Rev. 2.1 standard. It supports IDE interface for Fast HDD (Mode 0~4)
and Ultra DMA/33, as well as IDE Bus Master. These features also meet present and
future interface standards and needs.

System BIOS features include Plug-and-Play (PnP), Advanced Configuration Power

Interface (ACPI), the newest Desktop Management Interface (DMI), as well as IT5A’s
unique CPU operating frequency and voltage setup feature in order to meet modern
computing demands.

1-2 Chapter 1

IT5A

nSpecifications

1. Supports ATX power supply

2. Adjustment for Frequency and Voltage: Uses a DIP switch or jumper wires to adjust
the frequency and voltage on the mainboard

3. Uses ZIF CPU Socket 7 for easy CPU installation

Supports switching power for a more stable environment for the CPU
Supports Intel CPUs:

1) Pentium 100, 133, 166, and 200MHz

2) Pentium processor with MMXTM technology 166MHz to 233MHz

Supports AMD CPUs:

1) AMD-K5* PR100, PR133, and PR166.

2) AMD-K6

3) AMD-K6 3DTM 266 to 300MHz

Supports Cyrix/IBM CPUs:

1) Cyrix 6x86MX

TM

166MHz to 233MHz .

TM

PR166 ~ PR266

Supports IDT WinChip C6 CPU : 200MHz.

*Reserved circuitry supports future sixth generation CPUs

4. Chipset
ALi Aladdin V ( M1541 . M1543 ) chipset

Supports standard version PCI 2.1
Supports AGP 66/133 MHz ( Side band ) 3.3V devices

5. L2 Cache Memory
512K of cache memory (Pipeline Burst SRAM)

6. System DRAM
Two 168-pin DIMM sockets: support EDO and Synchronous DRAM (SDRAM)

DIMM sockets use PC modules (3.3V Unbuffered DRAM)
Up to 256MB memory configuration possible

Introduction of IT5A Features

)

7. System BIOS
AWARD BIOS

Supports Plug-and-Play (PnP)
Supports Advanced Configuration Power Interface (ACPI)
Supports Desktop Management Interface (DMI)

8. Multi I/O features
Two Universal Serial Bus (USB) ports

Two fast IDE channels (PIO mode 0~4, Ultra “DMA/33” and Bus Master)
One standard EPP/ECP parallel port and two 16550 serial ports
Two floppy disk drive connectors (FDD) (360K, 720K, 1.2M, 1.44M and 2.88M
Supports PS/2 type mouse and keyboard

9. Other features
Standard ATX architecture dimensions

One AGP slot , three PCI bus slots and two ISA bus slots and
Supports 3-MODE for a special Japanese floppy disk drive
Supports two bootable hard disks--able to run two different operating systems
Supports IDE ( ATAPI ) interface CD-ROM , ZIP and LS-120 type floppy disk
drive (Boot only)

1- 3

Note: All brand names and trademarks are the property of their respective owners.

1-4 Chapter 1

n

Layout diagram

Fig 1-1 Layout diagram

Introduction of IT5A Features

n

System block diagram

1- 5

Fig. 1-2 IT5A System block diagram

1-6 Chapter 1

Installing the Mainboard

2- 1

Chapter 2 Installing the Mainboard

This IT5A mainboard not only can be used with all standard equipment for
traditional personal computers, but also provides great flexibility for meeting
future upgrade demands. This chapter will introduce step by step all the
standard equipment and will also present, as completely as possible future upgrade
capabilities. This mainboard is able to support all Intel Pentium chips including
P55C with MMX, Cyrix 6x86MX and AMD-K5/K6/K6-3D processors now on
the market. (For details, see specifications in Chapter 1.) However, we cannot
guarantee the description given in this manual of the circuitry of your mainboard
will work for processors not listed in Chapter 1. For example, the operating
voltage of Cyrix’s next generation CPU is unknown at present. Thus we were not
able to include these specifications in your motherboard. We will supply further
information about CPU support when new CPUs arrive on the market.

This chapter is organized according the following features:

ΠInstalling the Mainboard to the Casing

• Standard external connectors
Ž Jumpers and switches

• Presentation and Installing of the CPU.

º Installing the system memory.

NNNN

Before proceeding with the installation

Before installing the mainboard please be sure to turn off or disconnect the
power supply unit. Before making any modifications to the hardware
configuration of the mainboard, the power supply to any areas of the mainboard
you plan to modify should be turned off to avoid unnecessary damage to the
hardware.

2-2 Chapter 2

&

User friendly instructions

Our objective is to enable the novice computer user to perform the installation
by themselves. We have attempted to write this document in a very clear, concise
and descriptive manner to help overcome any obstacles you may face during
installation. Please read our instructions carefully and follow them step-by-step.

Installing the Mainboard

¬

Installing the Mainboard to the Casing

Most computer cases will have a base on which there will be many mounting
holes that allows the mainboard to be securely attached and at the same time,
prevents short circuits.

There are two ways to attach the mainboard to the base.

with spacers
or with bolts

In principle, the best way to attach the motherboard is with bolts, and only if
you are unable to do this should you attach the board with spacers. Take a careful
look at the mainboard and you will see many mounting holes on it. Line these
holes up with the mounting holes on the base. If the holes line up, and there are
screw holes this means you can attach the mainboard with bolts. If the holes line
up and there are only slots, this means you can only attach the mainboard with
spacers. Take the tip of the spacers and insert it into the slots. After doing this to
all the slots, you can slide the mainboard into position aligned with the slots. After
the mainboard has been positioned, check to make sure everything is OK before
putting the casing back on.

2- 3

Note: If the mainboard has mounting holes, but don’t line up with the holes on
the base and their are no slots to attach the spacers, don’t worry, you can still
attach the spacers to the mounting holes. Just cut the spacers (along the dotted line)
(the spacer may be a little hard so be careful of our hands). In this way you can still
attach the mainboard to the base without worrying about short circuits.

2-4 Chapter 2

-

Standard External Connectors

Inside the case of any computer several cables and plugs have to be
connected. These cables and plugs are usually connected one-by-one to
connectors located on the mainboard. You need to carefully pay attention to
any connection orientation the cables may have and, if any, notice the position of
the first pin of the connector. In the explanation that follows, we will describe
the significance of the first pin.

Fig 2-1 External connectors layout

PN2 - Keylock connector Please pay attention to pin position and orientation

This connector has a specific orientation. Connect the five-thread keylock
connector cable to the PN2 connector pins on the mainboard.

Pin number Name or significance of signal

1 +5VDC
2 No connection
3 Ground
4 Keyboard inhibit Signal
5 Ground

Installing the Mainboard

2- 5

The “keylock switch” is used to lock the computer’s keyboard.
This disables the keyboard so that unauthorized persons cannot use it.
When this function is in use, you will need to use the unlock key to
activate the keyboard.

PN1 - Power ON/OFF switch

There is no specific orientation. Since most cases do not support this feature, most
of you should ignore this instruction.

Pin number Name or significance of the signal

8 Ground
9 Power on/off signal

PN2 - SMI Switch

There is no specific orientation. Connect the two-thread cable to the PN1
connector pins on the mainboard. Since most cases do not support this feature,
most of you should ignore this instruction. Furthermore, this feature is not
necessary as it is already a part of the mainboard.

Pin number Name or significance of signal

10 SMI signal
11 GND

PN2 - HDD LED connector

This connector has a specific orientation. Connect the two-thread IDE LED
connector cable attached to the case to the IDE LED connector on the mainboard.

Pin number Name or significance of signal

6 LED’s Cathode
7 LED’s Anode

PN1 - Speaker connector

There is no specific orientation. Connect the four-thread speaker cable to the
PN1 connector pins on the mainboard.

Pin number Name or significance of signal

4 +5VDC
5 Ground
6 Ground
7 Sound Signal

2-6 Chapter 2

PN1 - Hardware Reset connectors

There is no specific orientation. Connect the two-thread hardware reset cable
to the PN1 connector pins on the mainboard.

Pin number Name or significance of signal

1 Hardware reset signal
2 Ground

PN1 - Sleep LED connector

This connector has a specific orientation. Connect the two-thread Sleep LED
connector cable attached to the case to the Sleep LED connector on the
mainboard.

Pin number Name or significance of signal

9 LED’s Cathode

10 LED’s Anode

FAN1 - CPU Fan power connector

This has a specific orientation. Connect the three-threads CPU fan cable to the
FAN1 connector.

Pin number Name of the signal or signification

1 Control on / off
2 +12V
3 Sensor

Installing the Mainboard

2- 7

ATXPWR - ATX Power input Connectors

These have a specific orientation. The three warning marks indicate that if you
make a mistake in pin number or connection orientation, you could destroy your
equipment. During installation, you just need to connect to the correct pins and in
the correct orientation, and to connect the power supply unit to the connector on
the mainboard.

Pin number Name of the signal or

signification
1 +3.3VDC 11 +3.3VDC
2 +3.3VDC 12 -12VDC
3 Ground 13 Ground
4 +5VDC 14 PS_ON
5 Ground 15 Ground
6 +5VDC 16 Ground
7 Ground 17 Ground
8 POWERGOOD 18 -5VDC
9 +5VDC 19 +5VDC

10 +12VDC 20 +5VDC

Pin number Name of the signal or

signification

Fig 2-2 Mechanics of Mouse/Keyboard/USB/COM1/COM2/LPT

2-8 Chapter 2

MOUSE - PS/2 Mouse Connector

Attach a PS/2 mouse to this 6-pin Din-connector.

Pin number Name or significance of signal

1 Mouse data
2 No connection

3 Ground
4 +5VDC
5 Mouse clock
6 No connection

KB - PS/2 Keyboard Connector

Attach a keyboard to this 6-pin Din-connector.

Pin number Name or significance of signal

1 Keyboard data
2 No connection

3 Ground
4 +5VDC
5 Keyboard clock
6 No connection

Storage device connectors Watch the pin number and the orientation

Connector name Pin number Name of the peripheral connected

IDE 1 40 IDE Primary Channel
IDE 2 40 IDE Secondary Channel

FDC 34 Floppy Disk connector

Installing the Mainboard

®

Jumpers and Switches

CCMOS : Delete the contents of the CMOS ( 5 VSB POWER OFF )

This jumper is set on pins 1 and 2 at the factory in order for the
computer to function normally, so please do not change this setting. The
main feature of this jumper is to solve situations where the computer
crashes due to improper usage. For example:

-You have forgotten the password you set.

-You have inappropriately changed the settings in the BIOS

menu.

-You want to change the flash BIOS version.

All these errors are very serious, you must avoid them. But if you have
made one of these errors, this jumper can save your life. First turn off
the power supply and open the computer case. Place the jumper on pins
2 and 3 in order to save your computer. But if you use your computer
normally, you should not need to use this feature.

2- 9

After you have deleted the CMOS information, the computer is saved, but you
still have to go back to the BIOS Setup menu, and reset one by one all the
specifications: CPU, date, hour, FDD and HDD parameters. etc., before your
computer will return to normal operation.

2-10 Chapter 2

¯

Presentation and Installation of the CPU

Since 1996, every two or three months, Intel adds new models to the Pentium
CPU series. That is why the CPU market is filled with a lot of different models and
brands. All CPUs have different electrical specifications. That’s why installing a
CPU is becoming more and more complex. You can’t help that, because
everybody wants to be able to upgrade their hardware. So, you have to take a bit
of time to read this section, in order to be able to install a cheaper and better
processor.

The IT5A mainboard does not only support all the CPUs listed in the
specifications, but also has reserved several circuits in order to be able to support
future processors.

Related terminology :

External clock

Also referred to as the external CPU clock, or “Bus clock”, it is the input

clock of the CPU. For instance, Intel Pentium P90, P120 and P150 all have a

60MHz external CPU clock, but have different internal clock multiplier

factors.

Clock multiplier factor

The real operation clock within the CPU is the multiple of the external clock.

We refer to this factor as the clock multiplier factor. The four factors possible

are 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5. The factor differs from one CPU to

another. For instance, the Intel Pentium 166 CPU has a 66MHz external

clock, with a multiplier factor of 2.5, so that the speed of the internal clock is

66MHz x 2.5.

Internal clock

Also referred to as the real internal CPU clock, it is the actual internal

operating clock of the CPU. The Internal Clock is a multiple of the external

clock and of the clock multiplier factor. For instance, the Intel Pentium 90

CPU has a 60MHz external clock and its clock multiplier factor is 1.5; the

Intel Pentium P133 CPU has a 66MHz external clock and its clock multiplier

factor is 2.

Internal CPU clock = clock multiplier factor * external CPU clock

Installing the Mainboard

AT Bus clock

Also referred to as ISA SPEED, or AT CLOCK, or even ISA Bus clock. Ten
years ago, the original specification of AT Bus clock installed in the first
generation PC/AT computers was 8MHz, this means that there are some
interface cards which can only work at 8MHz. In order to guarantee
compatibility with older hardware, we still support 8MHz AT Bus clock, but
if your interface card is newer or faster, you can choose a higher speed for
the AT Bus clock, in order to increase the transmission rate of the interface
cards. But we recommend you not be too ambitious. An 8MHz setup ensures
maximum compatibility.

CPU Voltage - Vcore and Vio

From the voltage point of view, 586 series CPU can be divided into two
categories: single voltage CPU and dual voltage CPUs. Single voltage CPUs
include: Intel Pentium P54C series, AMD-K5 and Cyrix 6x86, etc.
Dual voltage CPUs include: Intel P55C with MMX, future AMD-K6 CPUs,
Cyrix 6x86L and 6x86MX.
The voltage of dual voltage CPUs has two components: Vcore and Vio.
Vcore provides all the power for internal processing, and its power
consumption is quite important. Vio provides the power necessary for the
external interface of the CPU.

2- 11

P-Rating

The P-Rating was defined by some manufacturers other than Intel to rate the
performance of their CPU in comparison with Intel Pentium CPUs. For
instance, Cyrix 6x86 P166+ has a higher actual speed compared with Intel
Pentium P166, its internal clock needs only 133MHz versus 166MHz for
Intel’s product. The main reason is that Cyrix has improved the internal
architecture of the 6x86 CPU, which means that with the same internal clock
speed, the actual clock speed will be different.

Voltage and Frequency Setup

IT5A uses DIP switches to setup the CPU Frequency and voltage. Please
make sure which kind of CPU and its frequency and voltage before you setup.

There are two DIP switches on the mainboard, one is use to setup the CPU
frequency (including external clock and rating parameter) which is called
SW2, another one is SW1 which is used to setup the CPU voltage.

2-12 Chapter 2

60MHz60MHz30MHzONONON66.6MHz66.6MHz33.3MHzONONOFF68MH68.4MH34.2MHONOFFON75MHz60MHz30MHzOFFONON83.3MHz66.6MHz33.3MHzOFFONOFF100MHz66.6MHz33.3MHzOFFOFFOF

F

1. IT5A CPU frequency setting (SW2)
The following tables will present the adjustment for the 586 CPU series.

Please setup the correct adjustment regarding the CPU type and brand.

Clock Chip:PLL52C66-08
External Clock AGP PCI DS6 DS7 DS8

Intel CPU

Intel

Pentium/with

MMX

External
Clock

Internal
Clock

External Clock

Factor

DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8

Reserve External Clock

Frequency

P100 66MHz 100MHz OFF OFF OFF OFF OFF ON ON OFF
P133 66MHz 133MHz ON OFF OFF OFF OFF ON ON OFF
P166 66MHz 166MHz ON ON OFF OFF OFF ON ON OFF
P200 66MHz 200MHz OFF ON OFF OFF OFF ON ON OFF
P233 66MHz 233MHz OFF OFF OFF OFF OFF ON ON OFF

AMD CPU

AMD­K5/K6

K5-PR100 66MHz 100MHz OFF OFF OFF OFF OFF ON ON OFF
K5-PR133 66MHz 100MHz ON OFF OFF OFF OFF ON ON OFF
K5-PR166 66MHz 117MHz ON ON OFF OFF OFF ON ON OFF
K6-166 66MHz 166MHz ON ON OFF OFF OFF ON ON OFF
K6-200 66MHz 200MHz OFF ON OFF OFF OFF ON ON OFF
K6-233 66MHz 233MHz OFF OFF OFF OFF OFF ON ON OFF
K6-266/3D 100MHz 266MHz ON ON OFF OFF OFF OFF OFF OFF

External
Clock

Internal
Clock

External Clock

Factor

DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8

Reserve External Clock

Frequency

K6-300/3D 100MHz 300MHz OFF ON OFF OFF OFF OFF OFF OFF

Installing the Mainboard

IDT WinChip C6 CPU

IDT­WinChip
C6

C6-200 66MHz 200MHz OFF ON OFF OFF OFF ON ON OFF

External
Clock

Internal
Clock

External Clock

Factor

DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8

Reserve External Clock

Frequency

Cyrix/IBM 6x86MX CPU

Cyrix/IBM External

Clock

6x86MX DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8
PR166 66MHz 133MHz ON OFF OFF OFF OFF ON ON OFF
PR200 66MHz 166MHz ON ON OFF OFF OFF ON ON OFF

75MHz 150MHz ON OFF OFF OFF OFF OFF ON ON

PR233 66MHz 200MHz OFF ON OFF OFF OFF ON ON OFF

75MHz 188MHz ON ON OFF OFF OFF OFF ON ON

Internal
Clock

External Clock

Factor

Reserve External Clock

Frequency

2- 13

83MHz 166MHz ON OFF OFF OFF OFF OFF ON OFF

PR266 66MHz 233MHz OFF OFF OFF OFF OFF ON ON OFF

The turbo mode can be set when the CPU external clock can support.
The turbo mode will increase the external clock by about 2.5%. It is used to
verify the frequency tolerance at the design phase. It is very important for the
designer to conduct some tests. Please do not setup the turbo mode during
normal operation if you are not familiar with CPU architecture .

There are eight switches at SW2, DS1-DS3 are used to setup the rating
parameter and DS6-DS8 are used to setup the external clock. The following
tables present all of the adjustments for the setup combinations of CPU.

2.CPU Voltage and Setup (SW2)
For the voltage of the 586 series CPU, there are two kinds of operation
modes depending on the different CPUs; single voltage and dual voltage.
Please make sure what working voltage that you use before installation.
The following table presents all of the adjustments of voltage for all of the
586 series CPUs, Please setup the Vcore voltage for the CPU you are using.
For the Vio voltage will be 3.52V as VRE recommand for dual-voltage.

2-14 Chapter 2

SW2 CPU Vcore settings

Nominal
Output Voltage
DACOUT

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

3.1

3.2

Pin Name S1

VC1 VC2 VC3 VC4 VC5

OFF OFF OFF OFF OFF
ON OFF OFF OFF OFF
OFF ON OFF OFF OFF
ON ON OFF OFF OFF
OFF OFF ON OFF OFF
ON OFF ON OFF OFF
OFF ON ON OFF OFF
ON ON ON OFF OFF
OFF OFF OFF ON OFF
ON OFF OFF ON OFF
OFF ON OFF ON OFF
ON ON OFF ON OFF
OFF OFF ON ON OFF

3.3

3.4

3.5

ON OFF ON ON OFF
OFF ON ON ON OFF
ON ON ON ON OFF

Installing the Mainboard

VIO VC6 VC7 VC8

2- 15

3.3

3.38

3.52

3.60

3.68

3.80

3.86

OFF OFF OFF
OFF OFF ON
OFF ON OFF
ON OFF OFF
ON OFF ON
ON ON OFF
ON ON ON