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SCI 486SX/DX SYSTEM BOARD

SCI SYSTEMS, INC.

SCI 486SX/DX SYSTEM BOARD

Processor

80486SX/80486DX

Processor Speed

25/33MHz

Chip Set

OPTI

Max. Onboard DRAM

64MB

Cache

64/256KB

BIOS

Unidentified

Dimensions

330mm x 218mm

I/O Options

Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA port

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

PS/2 mouse port

J1

IDE interface LED

J23

IDE interface

J5

Reset switch

J24

Floppy drive interface

J6

Speaker

J25

Parallel port

J8

Power LED & keylock

J26

Serial port 2

J9

VGA port

J27

Serial port 1

J10

   

USER CONFIGURABLE SETTINGS

Function

Jumper/Switch

Position

»

Monitor type select color

W1

pins 1 & 2 closed

 

Monitor type select monochrome

W1

pins 2 & 3 closed

»

CMOS memory normal operation

W2

pins 1 & 2 closed

 

CMOS memory clear

W2

pins 2 & 3 closed

»

SYSCLK enabled

W3

pins 2 & 3 closed

 

SYSCLK/2 enabled

W3

pins 1 & 2 closed

»

On board VGA enabled

W10

pins 1 & 2 closed

 

On board VGA disabled

W10

pins 2 & 3 closed

»

Video horizontal scan rate select 31.5 kHz

SW1/5

On

 

Video horizontal scan rate select 40kHz

SW1/5

Off

»

Video memory select 512KB

SW1/6

On

 

Video memory select 1MB

SW1/6

Off

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

1MB

(1) 256K x 36

NONE

NONE

NONE

2MB

(1) 256K x 36

(1) 256K x 36

NONE

NONE

4MB

(1) 1M x 36

NONE

NONE

NONE

5MB

(1) 256K x 36

(1) 1M x 36

NONE

NONE

6MB

(1) 256K x 36

(1) 256K x 36

(1) 1M x 36

NONE

8MB

(1) 1M x 36

(1) 1M x 36

NONE

NONE

9MB

(1) 256K x 36

(1) 1M x 36

(1) 1M x 36

NONE

10MB

(1) 256K x 36

(1) 256K x 36

(1) 1M x 36

(1) 1M x 36

12MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

NONE

13MB

(1) 256K x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

16MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

16MB

(1) 4M x 36

NONE

NONE

NONE

20MB

(1) 1M x 36

(1) 4M x 36

NONE

NONE

20MB

(1) 4M x 36

(1) 1M x 36

NONE

NONE

24MB

(1) 1M x 36

(1) 1M x 36

(1) 4M x 36

NONE

24MB

(1) 1M x 36

(1) 4M x 36

(1) 1M x 36

NONE

24MB

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

NONE

28MB

(1) 1M x 36

(1) 1M x 36

(1) 4M x 36

(1) 1M x 36

28MB

(1) 1M x 36

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

28MB

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

32MB

(1) 4M x 36

(1) 4M x 36

NONE

NONE

36MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

NONE

36MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

NONE

36MB

(1) 4M x 36

(1) 4M x 36

(1) 1M x 36

NONE

40MB

(1) 1M x 36

(1) 1M x 36

(1) 4M x 36

(1) 4M x 36

40MB

(1) 1M x 36

(1) 4M x 36

(1) 4M x 36

(1) 1M x 36

40MB

(1) 4M x 36

(1) 1M x 36

(1) 4M x 36

(1) 1M x 36

40MB

(1) 4M x 36

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

DRAM CONFIGURATION (CON’T)

Size

Bank 0

Bank 1

Bank 2

Bank 3

48MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

NONE

52MB

(1) 1M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

52MB

(1) 4M x 36

(1) 1M x 36

(1) 4M x 36

(1) 4M x 36

52MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

(1) 1M x 36

64MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

64KB

(4) 8K x 8

(4) 8K x 8

(2) 16K x 4

256KB

(4) 32K x 8

(4) 32K x 8

(2) 16K x 4

CACHE JUMPER CONFIGURATION

Size

W4

W5

W9

W11

64KB

pins 2 & 3 closed

pins 2 & 3 closed

pins 2 & 3 closed

pins 2 & 3 closed

256KB

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed

CPU TYPE CONFIGURATION

Type

W6

W7

W8

486SX

pins 2 & 3 closed

pins 2 & 3 closed

N/A

487SX

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

486DX

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed

VIDEO CONFIGURATION (800 X 600)

Refresh rate

SW1/1

SW1/2

»

60Hz

Off

On

 

56Hz

Off

Off

 

56Hz

On

On

 

72Hz

On

Off

VIDEO CONFIGURATION (1024 X 768)

Refresh rate

SW1/3

SW1/4

»

Interlaced

Off

Off

 

60Hz

Off

On

 

70Hz

On

Off

 

72Hz

On

On

VIDEO MEMORY CONFIGURATION

Size

Bank 0

Bank 1

512KB

(4) 256K x 4

NONE

1MB

(4) 256K x 4

(4) 256K x 4

Note: Bank 0 is factory installed and is not configurable.