ABC COMPUTER COMPANY, LTD.

A4879

Processor

80486SX/80487SX/80486DX

Processor Speed

25/50MHz

Chip Set

UMC

Max. Onboard DRAM

64MB

SRAM Cache

64/128/256KB

BIOS

AMI

Dimensions

220mm x 330mm

I/O Options

None

NPU Options

4167

CONNECTIONS

Purpose

Location

Purpose

Location

Power LED & keylock

J1

Reset switch

J4

Speaker

J2

Turbo LED

J5

Turbo switch

J3

External battery

J6

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Monitor type select color

W18

closed

 

Monitor type select monochrome

W18

open

»

Battery type select internal

W22

closed

 

Battery type select external

W22

open

SRAM JUMPER CONFIGURATION

Jumper

64KB

128KB

256KB

W2

pins 1 & 2 closed

pins 2 & 3 closed

pins 2 & 3 closed

W3

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed

W4

open

pins 2 & 3 closed

pins 2 & 3 closed

W5

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

W6

open

closed

closed

W7

open

open

closed

W8

open

open

closed

W9

open

closed

closed

SRAM CONFIGURATION

Size

Cache SRAM

Location

TAG (U10)

TAG (U11)

64KB

(8) 8K x 8

Banks 0 & 1

(1) 16K x 4

(1) 8K x 8

128KB

(4) 32K x 8

Bank 0

(1) 16K x 4

(1) 32K x 8

256KB

(8) 32K x 8

Banks 0 & 1

(1) 16K x 4

(1) 32K x 8

CPU JUMPER CONFIGURATION

CPU

Jumper W10

Jumper W11

Jumper W14

80486DX

pins 1 & 2 closed

pins 1 & 2 and 3 & 4 closed

open

80487SX

pins 2 & 3 closed

pins 1 & 2 and 3 & 4 closed

closed

80486SX

open

pins 2 & 3 closed

closed

Note:The location of W14 is unknown.

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

Jumpers

W12,W13,W15,W16

1MB

(4) 256K x 9

NONE

NONE

NONE

pins 1 & 2 closed

1MB

NONE

NONE

(1) 256K x 36

NONE

pins 2 & 3 closed

2MB

(4) 256K x 9

(4) 256K x 9

NONE

NONE

pins 1 & 2 closed

2MB

NONE

NONE

(1) 256K x 36

(1) 256K x 36

pins 2 & 3 closed

3MB

(4) 256K x 9

(4) 256K x 9

(1) 256K x 36

NONE

pins 1 & 2 closed

4MB

(4) 256K x 9

(4) 256K x 9

(1) 256K x 36

(1) 256K x 36

pins 1 & 2 closed

4MB

(4) 1M x 9

NONE

NONE

NONE

pins 1 & 2 closed

4MB

NONE

NONE

(1) 1M x 36

NONE

pins 2 & 3 closed

5MB

(4) 256K x 9

(4) 1M x 9

NONE

NONE

pins 1 & 2 closed

8MB

(4) 1M x 9

(4) 1M x 9

NONE

NONE

pins 1 & 2 closed

8MB

NONE

NONE

(1) 1M x 36

(1) 1M x 36

pins 2 & 3 closed

12MB

(4) 1M x 9

(4) 1M x 9

(1) 1M x 36

NONE

pins 1 & 2 closed

16MB

(4) 1M x 9

(4) 1M x 9

(1) 1M x 36

(1) 1M x 36

pins 1 & 2 closed

16MB

(4) 4M x 9

NONE

NONE

NONE

pins 1 & 2 closed

16MB

NONE

NONE

(1) 4M x 36

NONE

pins 2 & 3 closed

20MB

(4) 1M x 9

(4) 4M x 9

NONE

NONE

pins 1 & 2 closed

32MB

(4) 4M x 9

(4) 4M x 9

NONE

NONE

pins 1 & 2 closed

32MB

NONE

NONE

(1) 4M x 36

(1) 4M x 36

pins 2 & 3 closed

48MB

(4) 4M x 9

(4) 4M x 9

(1) 4M x 36

NONE

pins 1 & 2 closed

64MB

(4) 4M x 9

(4) 4M x 9

(1) 4M x 36

(1) 4M x 36

pins 1 & 2 closed

Note:The locations of jumpers W12, W13, W15,and W16 are unknown.