UNIDENTIFIED

SIS 486

Processor

CX486SX/80486SX/80487SX/CX486DX/80486DX/80486DX2

Processor Speed

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

Chip Set

SIS

Max. Onboard DRAM

64MB

Cache

128/256KB

BIOS

AMI

Dimensions

254mm x 220mm

I/O Options

32-bit VESA local bus slots (3)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Auxiliary keyboard connector

CN1

Turbo switch

JP22 pins 15 - 17

External battery

CN3

Reset switch

JP22 pins 19 - 20

Power LED & keylock

JP22 pins 1 - 5

Bus mouse port

JP22 pins 19 - 20

Speaker

JP22 pins 6 - 10

32-bit VESA local bus slots

SL1 - SL3

Turbo LED

JP22 pins 12 - 13

   

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Battery type select internal

CN3

pins 2 & 3 closed

 

Battery type select external

CN3

Closed

»

Factory configured - do not alter

JGPC

N/A

»

Monitor type select monochrome

JP1

Open

 

Monitor type select color

JP1

Closed

»

PQFP CPU disabled

JP5

Closed

 

PQFP CPU enabled

JP5

Open

»

CPU speed select 50MHz (Cyrix only)

JP6

pins 1 & 2 closed

 

CPU speed select <50MHz (Cyrix only)

JP6

pins 2 & 3 closed

»

CPU type select all

JP16

pins 2 & 3 closed

 

CPU type select 80486DX-40/50 only

JP16

pins 1 & 2 closed

»

VESA card select normal

JP23

Open

 

VESA card select Genoa

JP23

Closed

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

4MB

(4) 256K x 9

(1) 256K x 36

(1) 512K x 36

4MB

NONE

(1) 512K x 36

(1) 512K x 36

8MB

(4) 1M x 9

(1) 512K x 36

(1) 512K x 36

20MB

(4) 4M x 9

(1) 512K x 36

(1) 512K x 36

4MB

(4) 1M x 9

NONE

NONE

8MB

NONE

(1) 1M x 36

(1) 1M x 36

8MB

(4) 1M x 9

(1) 1M x 36

NONE

12MB

(4) 1M x 9

(1) 1M x 36

(1) 1M x 36

16MB

NONE

(1) 4M x 36

NONE

16MB

(4) 4M x 9

NONE

NONE

32MB

NONE

(1) 4M x 36

(1) 4M x 36

64MB

(4) 4M x 9

(1) 4M x 36

(1) 4M x 36

DRAM CONFIGURATION

Size

JPA

JPB

JPC

4MB

pins 1 & 2 closed

pins 4 & 5 closed

pins 1 & 2 closed

4MB

pins 2 & 3 closed

Open

Open

8MB

pins 2 & 3 closed

pins 2 & 3 closed

pins 1 & 2 closed

20MB

pins 2 & 3 closed

pins 2 & 3 closed

pins 1 & 2 closed

4MB

Open

Open

pins 2 & 3 closed

8MB

pins 2 & 3 closed

Open

Open

8MB

Open

pins 4 & 5 closed

pins 1 & 2 closed

12MB

pins 1 & 2 closed

pins 4 & 5 closed

pins 1 & 2 closed

16MB

Open

Open

Open

16MB

Open

Open

pins 2 & 3 closed

32MB

pins 2 & 3 closed

Open

Open

64MB

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

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

JP2

JP3

JP4

128KB

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

256KB

pins 2 & 3 closed

pins 2 & 3 closed

pins 2 & 3 closed

CPU TYPE CONFIGURATION

Type

JP12

JP13

JP15

80486SX

Open

pins 2 & 3 closed

Open

80487SX

pins 2 & 3 closed

pins 1 & 2 closed

Closed

80486DX

pins 1 & 2 closed

pins 1 & 2 closed

Closed

80486DX2

pins 1 & 2 closed

pins 1 & 2 closed

Closed

CPU SPEED CONFIGURATION

Speed

JS0

JS1

JS2

25MHz

Open

Open

Closed

33MHz

Closed

Open

Open

40MHz

Closed

Closed

Open

50iMHz

Open

Open

Closed

50MHz

Open

Closed

pins 1 & 2 closed

66iMHz

Closed

Open

Open

VESA WAIT STATE CONFIGURATION

Wait states

JP8

0 wait states

pins 1 & 2 closed

1 wait state

pins 2 & 3 closed

BUS SPEED CONFIGURATION

CPU speed

JP9

<= 33MHz

pins 1 & 2 closed

> 33MHz

pins 2 & 3 closed