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VL-BUS 486 MAIN BOARD

SILICON STAR INTERNATIONAL, INC.

VL-BUS 486 MAIN BOARD

Processor

80486SX/80487SX/80486DX/80486DX2

Processor Speed

25/33/40/50(internal)/50/66(internal)MHz

Chip Set

UNI

Max. Onboard DRAM

32MB

Cache

64/128/256KB

BIOS

AMI/Award

Dimensions

330mm x 218mm

I/O Options

32-bit VESA local bus slots (2)

CONNECTIONS

Purpose

Location

Purpose

Location

Power LED & keylock

CN1

External battery

CN6

Speaker

CN3

Reset switch

CN8

Turbo LED

CN4

Power LED

LED1

Turbo switch

CN5

32-bit VESA local bus slots

S1 & S2

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

CMOS memory normal

JP12

pins 1 & 2 closed

 

CMOS memory clear

JP12

pins 2 & 3 closed

FAST A20 enabled

JP17

pins 1 & 2 closed

 

FAST A20 disabled

JP17

pins 2 & 3 closed

Monitor type select color

JP18

Closed

 

Monitor type select monochrome

JP18

Open

Factory configured - do not alter

JP23

pins 1 & 2 closed

Factory configured - do not alter

JP24

pins 1 & 2 closed

Factory configured - do not alter

JP25

pins 1 & 2 closed

Factory configured - do not alter

JP26

pins 2 & 3 closed

Power good signal detect from power supply

JP27

pins 2 & 3 closed

 

Power good signal detect from board

JP27

pins 1 & 2 closed

Factory configured - do not alter

JP28

pins 2 & 3 closed

DRAM CONFIGURATION

Size

Bank 0

Bank 1

1MB

(4) 256K x 9

NONE

2MB

(4) 256K x 9

(4) 256K x 9

4MB

(4) 1M x 9

NONE

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

NONE

32MB

(4) 4M x 9

(4) 4M x 9

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG write through U15

TAG write back U14,U15

64KB

(4) 8K x 8

(4) 8K x 8

8K x 8

(2) 8K x 8

128KB

(4) 32K x 8

NONE

8K x 8

(2) 8K x 8

256KB

(4) 32K x 8

(4) 32K x 8

32K x 8

(2) 32K x 8

CACHE JUMPER CONFIGURATION

Size

JP1

JP2

JP3

JP4

JP5

JP6

JP7

64KB write through

N/A

N/A

1 & 2

1 & 2

2 & 3

1 & 2

1 & 2

64KB write back

1 & 2

1 & 2

1 & 2

1 & 2

2 & 3

1 & 2

1 & 2

128KB write through

N/A

N/A

2 & 3

1 & 2

1 & 2

1 & 2

2 & 3

128KB write back

2 & 3

1 & 2

2 & 3

1 & 2

1 & 2

1 & 2

2 & 3

256KB write through

N/A

N/A

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

256KB write back

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

Note:Pins designated should be in the closed position.

CPU SPEED CONFIGURATION

Speed

JP20

JP21

JP22

25MHz

Closed

Open

Closed

33MHz

Open

Closed

Closed

40MHz

Closed

Open

Open

50iMHz

Closed

Open

Closed

50MHz

Open

Closed

Open

66iMHz

Open

Closed

Closed

CPU TYPE CONFIGURATION

CPU Type

JP13

JP14

JP15

JP16

80486SX PGA

open

pins 2 & 3 closed

Open

Closed

80486 SX PQFP

open

pins 2 & 3 closed

Open

Open

80487SX

pins 2 & 3 closed

pins 1 & 2 closed

Closed

N/A

80486DX, DX2

pins 1 & 2 closed

pins 1 & 2 closed

Closed

N/A

VESA WAIT STATE/BUS SPEED CONFIGURATION

CPU speed

Wait states

JP8

JP9

JP10

JP11

< 33MHz

0 wait states

pins 1 & 2

pins 1 & 2

pins 1 & 2

pins 1 & 2

> 33MHz

1 wait state

pins 2 & 3

pins 2 & 3

pins 2 & 3

pins 2 & 3

Note: Pins designated should be in the closed position.