SOYO COMPUTER CO., LTD.

486 VESA GREEN MAINBOARD

Processor

CX486S/80486SX/CX486DX/80486DX/80486DX2/Pentium Overdrive

Processor Speed

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

Chip Set

Unidentified

Max. Onboard DRAM

128MB

Cache

64/128/256KB

BIOS

AMI

Dimensions

254mm x 220mm

I/O Options

32-bit VESA local bus slots (2), green PC connector

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Green PC connector

J4

Turbo switch

J21

Power LED & keylock

J17

Turbo LED

J22

Speaker

J18

Green PC connector

JP28

Reset switch

J19

Green PC connector

JP34

External battery

J20

32-bit VESA local bus slots

SL1 & SL2

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Monitor type select monochrome

JP3

Open

 

Monitor type select color/EGA/VGA

JP3

Closed

»

CMOS memory normal operation

JP5

pins 1 & 2 closed

 

CMOS memory clear

JP5

pins 2 & 3 closed

»

CPU type select PGA

JP18

Closed

 

CPU type select PQFP

JP18

Open

»

Factory configured - do not alter

JP23

Open

»

Factory configured - do not alter

JP31

Open

»

Factory configured - do not alter

JP32

Open

»

Factory configured - do not alter

JP35

Open

»

Factory configured - do not alter

JP36

Open

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

5MB

(4) 256K x 9

(4) 1M x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

NONE

17MB

(4) 256K x 9

(4) 4M x 9

20MB

(4) 1M x 9

(4) 4M x 9

32MB

(4) 4M x 9

(4) 4M x 9

64MB

(4) 16M x 9

NONE

68MB

(4) 1M x 9

(4) 16M x 9

80MB

(4) 4M x 9

(4) 16M x 9

128MB

(4) 16M x 9

(4) 16M x 9

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

64KB

(4) 8K x 8

(4) 8K x 8

(1) 8K x 8

128KB

(4) 32K x 8

NONE

(1) 8K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

CACHE JUMPER CONFIGURATION

Size

JP24

JP25

JP26

64KB

Open

pins 1 & 2 closed

Open

128KB

pins 1 & 2 closed

pins 2 & 3 closed

pins 2 & 3 closed

256KB

pins 2 & 3 closed

pins 2 & 3 closed

pins 1 & 2 closed

CPU TYPE CONFIGURATION

Type

JP1

JP4

JP6

JP8

JP9

CX486SX

1 & 2

2 & 3

Open

Open

2 & 3

80486SX

2 & 3

1 & 2

Closed

Open

2 & 3

CX486DX

1 & 2

2 & 3

Open

Closed

1 & 2

80486DX

2 & 3

1 & 2

Closed

Closed

1 & 2

80486DX2

2 & 3

1 & 2

Closed

Closed

1 & 2

Pentium Overdrive

1 & 2

1 & 2

Open

Closed

1 & 2

Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION (CON’T)

Type

JP10

JP11

JP12

JP13

CX486SX

2 & 3

2 & 3

2 & 3

Open

80486SX

4 & 5

Open

Open

Open

CX486DX

2 & 3

2 & 3

2 & 3

2 & 3

80486DX

4 & 5

Open

Open

Open

80486DX2

4 & 5

Open

Open

Open

Pentium Overdrive

1 & 2

1 & 2

1 & 2

1 & 2

Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION (CON’T)

Type

JP16

JP17

JP29

JP33

CX486SX

1 & 2, 3 & 4

1 & 2, 3 & 4

2 & 3

2 & 3

80486SX

2 & 3

2 & 3

1 & 2

2 & 3

CX486DX

1 & 2, 3 & 4

1 & 2, 3 & 4

1 & 2

2 & 3

80486DX

2 & 3

2 & 3

1 & 2

2 & 3

80486DX2

2 & 3

2 & 3

1 & 2

2 & 3

Pentium Overdrive

2 & 3

2 & 3

1 & 2

1 & 2

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

50MHz

Open

Closed

Open

50MHz (Pentium Overdrive only)

Closed

Open

Closed

50iMHz

Closed

Open

Closed

66iMHz

Open

Closed

Closed