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VESA MAINBOARD SIS 486 (REV. 2)

CHAINTECH COMPUTER COMPANY, LTD.

VESA MAINBOARD SIS 486 (REV. 2)

Processor

80486SX/CX486M7/80486DX/80486DX2/Pentium Overdrive

Processor Speed

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

Chip Set

SIS

Max. Onboard DRAM

128MB

Cache

128/256/512KB

BIOS

AMI/Award

Dimensions

330mm x 218mm

I/O Options

32-bit VESA local bus slots (3), green PC connector

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

External battery

J1

Reset switch

J6

Turbo switch

J3

Power LED & keylock

J7

Turbo LED

J4

Green PC connector

JP26

Speaker

J5

32-bit VESA local bus slots

SL1 - SL3

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

SMOUT type select normal mode

J2

Closed

 

SMOUT type select standby mode

J2

Open

»

CMOS memory normal operation

JP16

pins 1 & 2 closed

 

CMOS memory clear

JP16

pins 2 & 3 closed

»

Factory configured - do not alter

JP18

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

65MB

(4) 256K x 9

(4) 16M x 9

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

128KB

(4) 32K x 8

NONE

(1) 8K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

512KB

(4) 128K x 8

NONE

(1) 32K x 8

CACHE JUMPER CONFIGURATION

Size

JP1

JP2

JP3

JP4

128KB

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2, 3 & 4 closed

pins 1 & 2 closed

256KB

pins 2 & 3 closed

pins 2 & 3 closed

pins 2 & 3, 4 & 5 closed

pins 1 & 2 closed

512KB

pins 1 & 2 closed

pins 2 & 3 closed

pins 1 & 2, 3 & 4 closed

pins 2 & 3 closed

CPU TYPE CONFIGURATION

Type

JP8

JP9

JP10

JP11

JP12

JP13

JP14

80486SX

2 & 3

Open

2 & 3

Open

3 & 4

1 & 2

2 & 3

CX486M7

1 & 2

Closed

2 & 3

2 & 3

2 & 3

Open

1 & 2

80486DX/DX2

1 & 2

Closed

2 & 3

2 & 3

3 & 4

1 & 2

2 & 3

P23S

2 & 3

Open

2 & 3

Open

3 & 4

1 & 2

2 & 3

P24D

1 & 2

Closed

1 & 2

2 & 3

1 & 2

2 & 3

2 & 3

P24S

1 & 2

Closed

2 & 3

2 & 3

3 & 4

1 & 2

2 & 3

P24T

1 & 2

Closed

1 & 2

1 & 2

3 & 4

Open

1 & 2

Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION (CON’T)

Type

JP15

JP21

JP22

JP24

JP25

JP30

80486SX

4 & 5

2 & 3

1 & 2

Open

Open

Open

CX486M7

2 & 3

1 & 2

2 & 3

2 & 3

2 & 3

Open

80486DX/DX2

4 & 5

2 & 3

1 & 2

Open

Open

Open

P23S

4 & 5

2 & 3

1 & 2

Open

Open

Open

P24D

4 & 5

2 & 3

1 & 2

Open

1 & 2

Closed

P24S

4 & 5

2 & 3

1 & 2

Open

Open

Open

P24T

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

Open

Note: Pins designated should be in the closed position.

CPU SPEED CONFIGURATION

Speed

JP5

JP6

JP7

25MHz

Open

Closed

Open

33MHz

Closed

Closed

Closed

40MHz

Open

Closed

Closed

50iMHz

Open

Closed

Open

50MHz

Closed

Open

Open

66iMHz

Closed

Closed

Closed

CPU CLOCK DELAY CONFIGURATION

Delay

JP20

0 delay

pins 1 & 2 closed

1 gate buffer delay

pins 2 & 3 closed

CPU INPUT FREQUENCY CONFIGURATION

input

JP23

Single input

pins 1 & 2 closed

Double input

pins 2 & 3 closed

VESA WAIT STATE CONFIGURATION

Wait states

JP28

0 wait states

pins 1 & 2 closed

1 wait state

pins 2 & 3 closed

BUS SPEED CONFIGURATION

CPU speed

JP29

<= 33MHz

pins 1 & 2 closed

> 33MHz

pins 2 & 3 closed