SOYO COMPUTER CO., LTD.

SY-025A2

Processor

80486SX/80487SX/80486DX/ODP486SX/80486DX2

Processor Speed

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

Chip Set

SIS

Max. Onboard DRAM

32MB

Cache

64/128/256KB

BIOS

AMI

Dimensions

220mm x 254mm

I/O Options

32-bit VESA local bus slots (2)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Keylock

J17

Turbo switch

J21

Speaker

J18

Turbo LED

J22

Reset

J19

32-bit VESA local bus slots (2)

S1 & S2

External battery

J20

   

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Monitor type select color

JP3

Closed

 

Monitor type select monochrome

JP3

Open

»

CMOS memory normal operation

JP5

pins 1 & 2 closed

 

CMOS memory clear

JP5

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

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

JP6

JP7

64KB

pins 1 & 2 closed

open

128KB

pins 2 & 3 closed

pins 1 & 2 closed

256KB

pins 2 & 3 closed

pins 2 & 3 closed

CPU TYPE CONFIGURATION

Type

JP13

JP14

JP15

JP16

80486SX (PQFP)

Open

pins 2 & 3 closed

Open

Open

80486SX (PGA)

Open

pins 2 & 3 closed

Open

Closed

80487SX

pins 2 & 3 closed

pins 1 & 2 closed

Closed

Closed

80486DX

pins 1 & 2 closed

pins 1 & 2 closed

Closed

Closed

80486DX2

pins 1 & 2 closed

pins 1 & 2 closed

Closed

Closed

CPU SPEED CONFIGURATION

Speed

OSC at Y1

JP8 - JP11

JP20

JP21

JP22

25MHZ

25MHz

pins 1 & 2 closed

Closed

Open

Closed

33MHz

33MHz

pins 1 & 2 closed

Open

Closed

Closed

50iMHZ

25MHz

pins 1 & 2 closed

Closed

Open

Closed

50MHz

50MHz

pins 2 & 3 closed

Open

Closed

Open

66iMHz

33MHz

pins 1 & 2 closed

Open

Closed

Closed

Notes:The board may come with a clock generator at Y1.

JP8 controls VESA bus slot S1's speed, JP9 Controls VESA bus slot S1's wait states.

JP10 controls VESA bus slot S2's speed, JP11 Controls VESA bus slot S2's wait states.