FOREX COMPUTER CORPORATION

FOREX 486 (REV. VL3H)

Processor

80486SX/80487SX/80486DX/80486DX2/P23T/P24T

Processor Speed

20/25/33/40/50(internal)/50/66(internal)MHz

Chip Set

Forex

Video Chip Set

None

Maximum Onboard Memory

32MB

Maximum Video Memory

None

Cache

64/128/256KB

BIOS

AMI

Dimensions

260mm x 220mm

I/O Options

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

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Turbo LED

J6

External battery

JP1

Speaker

J7

Green PC connector

JP14

Turbo switch

J8

Green PC LED

JP15

Power LED & keylock

J9

32-bit VESA local bus slots

SL1 – SL3

Reset switch

J10

   

USER CONFIGURABLE SETTINGS

Function

Label

Position

 

PQFP CPU enabled

JP5

Open

 

PQFP CPU disabled

JP5

Closed

»

CMOS memory normal operation

JP6

Unidentified

 

CMOS memory clear

JP6

Unidentified

 

Green PC disabled

JP13

Open

 

Green PC enabled

JP13

Closed

 

Green clock speed select 8MHz

JP16

Pins 2 & 3 closed

Green clock speed select 16MHz

JP16

Pins 1 & 2 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

5MB

(4) 256K x 9

(4) 1M x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

None

20MB

(4) 1M x 9

(4) 4M x 9

32MB

(4) 4M x 9

(4) 4M x 9

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

64KB

(4) 8K x 8

(4) 8K x 8

(1) 8K x 8

128KB

(4) 32K x 8

None

(1) 8K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 16K/32K x 8

CACHE JUMPER CONFIGURATION

Size

JP8A

JP8B

JP8C

64KB

Pins 2 & 3 closed

Pins 1 & 2 closed

Pins 2 & 3 closed

128KB

Pins 1 & 2 closed

Pins 2 & 3 closed

Pins 1 & 2 closed

256KB

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

CPU SPEED SELECTION

Speed

JP7A

JP7B

JP7C

20MHz

Open

Closed

Closed

25MHz

Closed

Open

Open

33MHz

Open

Open

Open

40MHz

Closed

Closed

Open

50iMHz

Closed

Open

Open

50MHz

Open

Closed

Open

66iMHz

Open

Open

Open

CPU TYPE SELECTION

Type

JP2

JP3

JP4

JP12

80486SX

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 1 & 2 closed

80487SX

Pins 2 & 3 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

80486DX (PQFP)

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 1 & 2 closed

80486DX (PGA)

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

80486DX2

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

P23T

Pins 2 & 3 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

P24T

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 2 & 3 closed

CPU TYPE SELECTION (CYRIX ONLY)

Type

JP20

CX486DX

Open

CX486DX2

Closed

VL BUS WAIT STATE SELECTION

Setting

JP10

0

Pins 1 & 2 closed

1

Pins 2 & 3 closed

VL BUS SPEED SELECTION

Speed

JP11

<= 33MHz

Pins 1 & 2 closed

>33 MHz

Pins 2 & 3 closed