...because we can't all be on the bleeding edge...





AT420/AT425/AT433/AT450

ABIT COMPUTER CORPORATION

AT420/AT425/AT433/AT450

Processor

80486SX/80486DX

Processor Speed

20/25/33/50MHz

Chip Set

SIS

Max. Onboard DRAM

32MB

Cache

32/64/128/256/512/1024KB

BIOS

AMI

Dimensions

330mm x 218mm

I/O Options

None

NPU Options

4167

CONNECTIONS

Purpose

Location

Purpose

Location

Speaker

CN1

Turbo switch

JP1

Power LED & keylock

CN2

Turbo LED

JP2

External battery

CN3

Reset switch

SW1

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

CMOS memory normal operation

JP5

pins 1 & 2 closed

 

CMOS memory clear

JP5

pins 2 & 3 closed

Monitor type select monochrome

JP7

Open

 

Monitor type select color

JP7

Closed

Factory configured - do not alter

JP8

Open

Note:Jumper JPX3 is closed using an 8-pin terminating resistor.

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

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

Location

32KB

(4) 8K x 8

NONE

(1) 8K x 8

T-1

32KB

(4) 8K x 8

(4) 8K x 8

(2) 16K x 4

T-2

64KB

(4) 8K x 8

(4) 8K x 8

(1) 8K x 8

T-1

64KB

(4) 8K x 8

(4) 8K x 8

(2) 16K x 4

T-2

128KB

(4) 32K x 8

NONE

(1) 8K x 8

T-1

128KB

(4) 32K x 8

NONE

(2) 16K x 4

T-2

256KB

(4) 32K x 8

(4) 32K x 8

(2) 16K x 4

T-2

512KB

(4) 128K x 8

NONE

(1) 32K x 8

T-1

512KB

(4) 128K x 8

NONE

(2) 64K x 4

T-2

1024KB

(4) 128K x 8

(4) 128K x 8

(1) 128K x 8

T-1

1024KB

(4) 128K x 8

(4) 128K x 8

(2) 64K x 4

T-2

CACHE JUMPER CONFIGURATION

Size

JP3

JP4

JPX4

JPX5

32KB

Open

Open

pins 1 - 8 closed

pins 1 - 8 closed

64KB

Open

Open

pins 9 - 16 closed

pins 3 - 10 closed

128KB

Open

Closed

pins 1 - 8 closed

pins 5 - 12 closed

256KB

Open

Closed

pins 9 - 16 closed

pins 7 - 14 closed

512KB

Open

Closed

pins 1 - 8 closed

pins 9 - 16 closed

1024KB

Closed

Closed

pins 9 - 16 closed

pins 9 - 16 closed

Note:Jumpers JPX4 & JPX5 are closed using 8-pin terminating resistors.

CACHE JUMPER CONFIGURATION

Type

JP6

JPX3

80486SX

Closed

Open

80486DX

Open

Closed