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A4879

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.