ABIT COMPUTER CORPORATION

486SX-AR4

Processor

80486SX/80487SX/80486DX

Processor Speed

20/25/33MHz

Chip Set

Acer

Max. Onboard DRAM

32MB

Cache

None

BIOS

AMI

Dimensions

230mm x 220mm

I/O Options

None

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

External battery

J4

Turbo LED

J21 pins 1 & 2

Reset switch

J19

Turbo switch

J21 pins 4 & 5

Speaker

J20

Power LED & keylock

J22

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Monitor type select color

JP1

pins 2 & 3 closed

 

Monitor type select monochrome

JP1

pins 1 & 2 closed

»

Real time clock select MC146818

JP2

Open

 

Real time clock select DS1287

JP2

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

CPU TYPE CONFIGURATION

Type

JP4

JP5

80486SX

pins 1 & 2 closed

pins 2 & 3 closed

80487SX

Open

pins 1 & 2 closed

80486DX

pins 2 & 3 closed

pins 2 & 3 closed

I/O BUS SPEED CONFIGURATION

Speed

JP3

JP6

CLK2/5

pins 2 & 3 closed

pins 1 & 2 closed

CLK2/6

pins 1 & 2 closed

pins 2 & 3 closed

CLK2/8

pins 1 & 2 closed

pins 1 & 2 closed