UMC 486 VESA BUS Mainboard User's Manual

Chapter 1: Introduction

The UMC 486 system board is a high-performance personal computer system board based on an 80486 microprocessor running at 25/33/40/50 MHz. The board offers a socket for a hand-inserted CPU.

A cache subsystem can be configured for 32kb, 64kb, 128kb, or 256kb cache memory to improve overall throughput. The board also features three 32-bit Local Bus slots for VESA standard.

The UMC 486 system board uses the highly integrated UMC 491F chip that integrates all system control functions.

Features

The advanced features of the 4FVUD motherboard include:

One of the following CPUs:

• Intel i486DX CPU running at 33 or 50 MHz
• Intel i486DX2 CPU running at 50 or 66MHz
• Intel 80486SX CPU running at 20 or 25MHz

• Internal 8K cache with 4-way set associate algorithm built into the CPU
• External 32K/64K/128K/256K cache system
• Memory support up to 32Mbytes with combinations of 256K, 1M, and 4M SIMM modules
• Three 32-BIT VESA BUS MASTER slots
• Six 16-bit ISA slots and one 8-bit ISA slot
• AMI BIOS

UMC491 Placement Diagram

Diagram of the UMC 491 Motherboard Placement: The diagram shows the layout of the motherboard, including the CPU socket for an 80486 processor, the BIOS chip, an 8-bit slot, multiple 16-bit ISA slots, and three VL-BUS MASTER slots. It also indicates the location of the UMC 491F chip, cache memory (TAG SRAM), and main memory banks (Bank 0, Bank 1). Various jumpers (JP4-JP8, JP9, JP13, JP14, JP16) and connectors (8042, J3-J8) are also marked.

Chapter 2: Hardware Installation

Jumpers and Connectors

Jumpers

Jumpers on the system board provide information to your operating system about installed options and system settings. You need to configure jumpers when you install a CPU, select cache size, add an external battery, or clear CMOS memory.

Connectors

Connectors attach control panel switches and indicators, as well as the speaker, external battery, keyboard and power supply.

Setting Jumpers

CPU Type Selectors: JP3, JP13, JP14

The UMC 491 system board can support several types of CPU. To configure the system board to recognize which type of CPU is installed, you must set jumpers JP3, JP13, and JP14 as below.

Cache Memory Selection: JP4-JP8

The system board supports 32K, 64K, 128K or 256K of cache memory. You configure cache memory by installing 8K8 r 32K8 SRAM chips in Data RAM sockets U13 - U16 and U21-U26, and in TAG RAM socket U20, and then setting the cache jumpers.

Cache Size and Memory Locations

Cache Size Selection:

Memory Bank Configuration

The UMC 486 system board supports two memory banks on-board, numbered bank 0 and bank 1. The user does not need to care which bank they should install which type of DRAM. These functions are very convenient for the end-user.

Table 2-1: Possible Configurations

VL-Bus Master Setting: JP9, JP16

Settings

Chapter 3: AMIBIOS SETUP PROGRAM

BIOS SETUP PROGRAM AMI BIOS SETUP UTILITIES (C) 1990 American Megatrends Inc., All Rights Reserved

Menu Options:

• STANDARD CMOS SETUP
• ADVANCED CMOS SETUP
• ADVANCED CHIPSET SETUP
• AUTO CONFIGURATION WITH BIOS DEFAULTS
• AUTO CONFIGURATION WITH POWER-ON DEFAULTS
• CHANGE PASSWORD
• HARD DISK UTILITY
• WRITE TO CMOS AND EXIT
• DO NOT WRITE CMOS AND EXIT

Standard CMOS Setup for Changing Time, Date, Hard Disk Type, etc.

ESC:Exit Sel F2/F3: Color F10:Save & Exit

Figure 1: The generic menu options of the BIOS SETUP Program are shown in Figure 1.

A warning message, shown below, is displayed each time one of the first three options (Standard CMOS Setup, Advanced CMOS Setup, and Advanced Chips Set Setup) is selected, before any changes are shown to any of the setup parameters.

BIOS SETUP PROGRAM - WARNING INFORMATION

(C) 1990 American Megatrends Inc., All Rights Reserved

Improper Use of Setup may Cause Problems!!

If System Hangs, Reboot System and Enter Setup by Pressing the <DEL> key

Do any of the following After Entering Setup:

1. After Options to make System Work
2. Load BIOS Setup Defaults
3. Load Power-On Defaults

Hit <ESC> to Stop now, Any other key to Continue

STANDARD CMOS SETUP

BIOS SETUP PROGRAM-STANDARD CMOS SETUP (C) 1990 American Megatrends Inc., All Rights Reserved

Figure 2 Standard CMOS SETUP Screen

The Standard CMOS Setup utility is used to configure the following features:

• Date: Month, Date, and Year. Ranges for each value are listed below in prompt box in the lower left corner of the CMOS Setup Screen (Figure 2).
• Time: Hour, Minute, and Second. Uses 24 hour clock format, i.e., for PM numbers, add 12 to the hour. You would enter 4:30 P.M. as 16:30:00.
• Daylight Saving: Disabled or Enabled.
• Hard Disk C: Hard disk types from 1 to 46 are standard ones; and type 47 is user definable. The user must enter the hard disk parameters for each drive.
• Hard Disk D: (Same as Hard Disk C)

Note: The USER definition entry allows you to perform a test on a disk drive not defined in ROM. The USER definition entry is valid only during the period that the test is performed.

The drive types are identified by the following characteristics:

• Type: This is the number designation for a drive with certain identification parameters.
• Cyln: This is the number of cylinders found in the specified drive type.
• Head: This is the number of heads found in the specified drive type.
• WPcom: WPcom is the read delay circuitry which takes into account the timing differences between the inner and outer edges of the surface of the disk platter.
• L-zone: L-zone is the landing zone of the heads. This number determines the cylinder location where the heads will normally park when the system is shut down.
• Capacity: This is the formatted capacity of the drive based on the following formula: (# of heads) x (# of cylinders) x (17 secs/cyl) x (512 bytes/sec)

Attributes for Disk Types 1 through 46:

"Not Installed" is available for use as an option.

This option could be used for diskless workstations and SCSI hard disks. Type 47 may be used for both hard disks C: and D:. The parameters for type 47 under Hard Disk C: and Hard Disk D: may be different, which effectively allows 2 different user-definable hard disk types.

• Floppy Drive A and Floppy Drive B: The options are 360 KB 5 1/4", 1.2 MB 5 1/4", 720KB 3 1/2", 1.44MB 3 1/2", 2.88MB 3 1/2", and Not installed. Not installed could be used as an option for diskless workstations.
• Primary Display: Options are Monochrome, Color 40 x 25, VGA/PGA/EGA, Color 80 x 25, and Not Installed. The Not installed option could be used for network file servers.
• Keyboard: Options are installed or Not installed.

ADVANCED CMOS SETUP

BIOS SETUP PROGRAM AMI BIOS SETUP UTILITIES (C) 1990 American Megatrends Inc., All Rights Reserved

Menu Options:

• STANDARD CMOS SETUP
• ADVANCED CMOS SETUP
• ADVANCED CHIPSET SETUP
• AUTO CONFIGURATION WITH BIOS DEFAULTS
• AUTO CONFIGURATION WITH POWER-ON DEFAULTS
• CHANGE PASSWORD
• HARD DISK UTILITY
• WRITE TO CMOS AND EXIT
• DO NOT WRITE CMOS AND EXIT

Advanced CMOS Setup for Configuring System Option

ESC: Exit Sel F2/F3: Color F10: Save & Exit

Figure 3

ADVANCED CMOS SETUP - Options

BIOS SETUP PROGRAM - ADVANCED CMOS SETUP (C)1993 American Megatrends Inc., All Rights Reserved

Figure 4

A short description follows for each of the options on the Advanced CMOS Setup Screen.

Typematic Rate Programming:

By enabling this option, the user can adjust the rate at which a keystroke is repeated. The options "Typematic Rate Delay" and "Typematic Rate" affect this rate. When a key is pressed and held down, the character appears on the screen and after a delay set by the Typematic Rate Delay, it keeps on repeating at a rate set by the Typematic Rate value. When two or more keys are pressed and held down simultaneously, only the last key pressed will be repeated at the typematic rate. This stops when the last key pressed is released, even if other keys are depressed.

Extended Memory Test:

This feature, when enabled, will invoke the POST memory routines on the RAM above 1 MB (if present on the system). If disabled, the BIOS will only check the first 1MB of RAM.

Memory Test Tick Sound:

This option will enable (turn on) or disable (turn off) the "ticking" sound during the memory test.

Memory Parity Error Check:

If the system board does not have parity RAM, the user may disable the memory parity error checking routines in the BIOS. The user should check with the manufacturer regarding the proper setting of this option.

Hit <DEL> Message Display:

Disabling this option, will prevent the message: "Hit <DEL> if you want to run SETUP" From appearing on the screen when the system boots-up.

Hard Disk Type 47 Data Area:

The AMI BIOS SETUP features two user-definable hard disk types. Normally, the data for these disk types are stored at 0:300 in lower system RAM. If a problem occurs with other software, this data can be located at the upper limit of the DOS shell (640KB). If the option is set to "DOS 1 KB," the DOS Shell is shortened to 639 KB, and the top KB is used for the hard disk data storage. Please refer to Figure 4 for this option.

Wait for <F1> If Any Error:

Before the system boots-up, the BIOS will execute the POST routines, a series of system diagnostic routines. If any of these tests fail, but a non-fatal error has occurred and the system can still function, the BIOS will respond with an appropriate error message followed by the following statement: "Press <F1> to continue." If this option is disabled, any non-fatal error which occurs will not generate the above statement, but the BIOS will still display the appropriate error message. This will eliminate the need for any user response to a non-fatal error condition message.

System Boot Up Num Lock:

The user may turn off the "numlock" option on his Enhanced Keyboard when the system is powered on. This will allow him to use the arrow keys on the numeric keypad instead of using the other set of arrow keys on the Enhanced Keyboard. The BIOS will default to turning the "num lock"

Floppy Drive Seek At Boot:

The default for this option is "Disabled" to allow a fast boot and to decrease the possibility of damage to the heads.

System Boot Up CPU Speed:

The speed at which the system will boot up is determined with this option. Choices for this option are "high" or "low". The default speed is "low".

System Boot Up Sequence:

The AMI BIOS will normally attempt to boot from floppy drive A: (if present), and if unsuccessful, it will attempt to boot from hard disk C:. This sequence can be switched using this option if the option is set to "C:,A:", the system will attempt to boot from the hard drive C: and then A:. If the option is set to "A:, C:", the sequence is reversed. Please refer to Figure 4 for this option.

Password Check Option:

The password feature can be used to prevent unauthorized system boot-up or unauthorized use of BIOS SETUP. The option in the BIOS SETUP only allows the user to enable the password check option every time the system boots or upon entering SETUP only. Second option is to disable the password option entirely.

The default option is "Setup." The prompt for the password will not appear when the system is rebooted.

If the "Always" option is chosen at Setup, each time the system is turned on, i.e. "booted," the prompt for user password will appear.

If the "Setup" option is chosen at Setup. The password prompt will not appear when the system is turned on, but will appear if the user attempts to enter the Setup program.

The program allows three attempts to key in the correct password. After each incorrect attempt, the prompt to enter the current password will appear, followed by an "X." After the third incorrect attempt, the system will lock and it will be necessary to reboot. The screen will not display the characters entered.

External Cache Memory:

With this option, the user may enable or disable the 64K, 128K, 256K External cache.

Internal Cache Memory:

With this option, the user may enable or disable the CPU's Internal Cache Memory.

Fast Gate A20 option:

This option supported in some chip sets, to assess any memory above 1MB.

BIOS SETUP PROGRAM - CHANGE PASSWORD

(C) 1993 American Megatrends Ins., All Rights Reserved

Eneter CURRENT Password:

Use Maximum 6 ASCII Characters, ESC:Exit

The first time you select this option, enter the default password AMI, or the default password specified in your system documentation, then press <Enter> to complete your selection. The screen will not display the characters entered. After the current password has been correctly entered, the screen in following Figure will appear, prompting you for the new password.

BIOS SETUP PROGRAM - CHANGE PASSWORD

(C) 1993 American Megatrends Inc., All Rights Reserved

Enter NEW Password:

Use Maximum 6 ASCII Characters, ESC:Exit

After the new password is entered, the prompt in above figure will appear. Rekey the new password and press <Enter>.

If the new password confirmation is entered without error, the screen in following will appear. Perss <ESC> to return to the Main Setup menu.

BIOS SETUP PROGRAM - CHANGE PASSWORD

(C) 1993 American Megatrends Inc., All Rights Reserved

NEW Password Installed

Use Maximum 6 ASCII Characters, ESC:Exit

Once Setup is completed and the changed values have been stored in the CMOS, when the system next boots. The user will be prompted for the password if the password function is present and has been enabled.

When and if the prompt appears is dependent upon the options chosen in Advanced CMOS Setup:

• If the "Always" option was chosen in Advanced CMOS Setup, the prompt will appear each time the system is powered on.
• If the "Setup" option was chosen in Advanced CMOS Setup, the prompt will not appear when the system is powered on, but will appear each time an attempt is made to enter the Setup program.
• If the "Disabled" option was chosen in Advancde CMOS Setup, the password prompt will never appear.

When the password prompt appears, the new password, which is now stored in the CMOS, should be entered and the <Enter> key pressed. If the CMOS is corrupted, e.g., the batteries fall out or are loosened, the default ROM password mentioned above should be used instead.

NOTE: When the password is changed, however, it is important that a record of the change be kept in a safe place. In the event the password check has been enabled in Setup and the user forgets or loses the new password, the default password stored in the ROM cannot be used unless the CMOS is disabled. A relatively safe way to do this would be to disconnect the CMOS batteries.

ADVANCED CHIPSET SETUP

BIOS SETUP PROGRAM AMI BIOS SETUP UTILITIES (C) 1993 American Megatrends Inc., All Rights Reserved

Menu Options:

• STANDARD CMOS SETUP
• ADVANCED CMOS SETUP
• ADVANCED CHIPSET SETUP
• AUTO CONFIGURATION WITH BIOS DEFAULTS
• AUTO CONFIGURATION WITH POWER-ON DEFAULTS
• CHANGE PASSWORD
• HARD DISK UTILITY
• WRITE TO CMOS AND EXIT
• DO NOT WRITE CMOS AND EXIT

Advanced CHIPSET Setup for Configuring the CHIPSET Registers

ESC: Exit Sel F2/F3: Color F10: Save & Exit

BIOS SETUP PROGRAM - ADVANCED CHIPSET SETUP (C) 1993 American Megatrends Inc., All Rights Reserved

AUTO Config Function

Choose Enabled or Disabled. Enabled automatically sets all parameters related to DRAM and cache. The automatic settings consider reliability and performance trade-offs. Enabled is the recommended option.

If you choose Enabled, the screen setting the following six items have no effect.

If you choose Disabled, you must set the DRAM and cache through the following four items.

Cache Read Option:

Cache Write Option:

DRAM Type:

DRAM Wait State(s):

Non-cacheable Bock

There are two non-cacheable areas. Each area has a 0KB to 4KB range that is selectable. Memory space is mapped by both the on board DRAM and EISA add-on memory. If you select DRAM as non-cacheable, the CPU access the add-on memory. If you select AT Bus as non-cacheable, the CPU access the on board memory. If you select a non-cacheable area size of 0KB, the function is disabled and the CPU access the on board memory first.

AT Clock Select:

I/O Recovery Select:

Choose 3, 4, 5, or 11 BCLKs. The system provides four type of programmable I/O recovery time for the CPU to 8-bit ISA I/O cycle.

APPEND A: CLOCK GENERATOR SETTING