R486SX254F/R486SX33F/R486DX334F/R486DX2664F Motherboard Settings and Configuration

Processor

80486SX/80487SX/80486DX/ODP486SX/80486DX2/Pentium Overdrive

Processor Speed

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

Chip Set

VLSI

Max. Onboard DRAM

32MB

Cache

64/128/256KB

BIOS

Phoenix

Dimensions

330mm x 218mm

I/O Options

32-bit proprietary riser card slot, floppy drive interface,IDE interface, parallel port, PS/2 mouse port,serial ports (2), VGA feature connector, VGA port

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

VGA port

J1

Floppy drive interface

J15

Parallel port

J2

+5V auxiliary fan power

J26

Serial port 2

J3

IDE interface LED

J29

Serial port 1

J4

Power LED & Keylock

J30

PS/2 mouse port

J5

Reset switch

J31

32 Bit proprietary riser card

J7

+12V auxiliary fan power

J32

VGA feature connector

J10

External speaker

J33

IDE interface

J14

Note:To connect an external speaker, remove the jumper from pins 3 & 4 and connect external speaker between pins 1 & 4.

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

FLASH BIOS programming enabled

J12

pins 1 & 2 closed

FLASH BIOS programming disabled

J12

pins 2 & 3 closed

»

Normal FLASH operation

J13

pins 1 & 2 closed

Invoke boot block recovery

J13

pins 2 & 3 closed

»

Enable onboard video

J16

pins 1 & 2 closed

Disable onboard video

J16

pins 2 & 3 closed

»

Disable floppy drive write protect

J17

pins 2 & 3 closed

Enable floppy drive write protect

J17

pins 1 & 2 closed

»

Enable password

J20

pins 2 & 3 closed

Disable password

J20

pins 1 & 2 closed

»

Enable user to enter Setup

J21

pins 1 & 2 closed

Prevent user to enter Setup

J21

pins 2 & 3 closed

»

CMOS normal operation

J28

Closed

CMOS clear upon power-up

J28

Open

DRAM CONFIGURATION

Size

Bank 0

Bank 1

2MB

(1) 512K x 36

NONE

4MB

(1) 512K x 36

(1) 512K x 36

4MB

(1) 1M x 36

NONE

6MB

(1) 512K x 36

(1) 1M x 36

6MB

(1) 1M x 36

(1) 512K x 36

8MB

(1) 1M x 36

(1) 1M x 36

8MB

(1) 2M x 36

NONE

10MB

(1) 2M x 36

(1) 512K x 36

10MB

(1) 512K x 36

(1) 2M x 36

12MB

(1) 2M x 36

(1) 1M x 36

16MB

(1) 1M x 36

(1) 2M x 36

16MB

(1) 2M x 36

(1) 2M x 36

16MB

(1) 4M x 36

NONE

18MB

(1) 512K x 36

(1) 4M x 36

18MB

(1) 4M x 36

(1) 512K x 36

20MB

(1) 1M x 36

(1) 4M x 36

20MB

(1) 4M x 36

(1) 1M x 36

24MB

(1) 2M x 36

(1) 4M x 36

24MB

(1) 4M x 36

(1) 2M x 36

32MB

(1) 4M x 36

(1) 4M x 36

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

64KB

(4) 8K x 8

(4) 8K x 8

(1) 32K x 8

128KB

(4) 32K x 8

NONE

(1) 32K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

CACHE JUMPER CONFIGURATION

Size

J11

64KB

Open

128KB

pins 1 & 2, 5 & 6 closed

256KB

pins 1 & 2, 3 & 4, 7 & 8 closed

CPU TYPE CONFIGURATION

CPU Type

J22

J23

J24

J25

80486SX

pins 1 & 2 closed

pins 2 & 3 closed

pins 2 & 3 closed

pins 2 & 3 closed

80487SX

pins 2 & 3 closed

pins 1 & 2 closed

pins 2 & 3 closed

pins 1 & 2 closed

80486DX

pins 2 & 3 closed

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed

80486DX2

pins 2 & 3 closed

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed

ODP486SX

pins 2 & 3 closed

pins 1 & 2 closed

pins 2 & 3 closed

pins 1 & 2 closed

CPU SPEED CONFIGURATION

CPU Speed

J18

J19

25MHz

pins 1 & 2 closed

pins 1 & 2 closed

33MHz

pins 1 & 2 closed

pins 2 & 3 closed

50iMHz

pins 1 & 2 closed

pins 1 & 2 closed

66iMHz

pins 1 & 2 closed

pins 2 & 3 closed

VRAM CONFIGURATION

Size

Bank 0

Bank 1

512K

(4) 256 x 4

NONE

1MB

(4) 256 x 4

(4) 256 x 4