YOUNG MICRO SYSTEMS, INC.

486 EISA/VESA

Processor

80486SX/80486DX/80486DX2/Pentium Overdrive

Processor Speed

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

Chip Set

VIA

Max. Onboard DRAM

64MB

Cache

64/128/256/512/1024KB

BIOS

AMI

Dimensions

330mm x 218mm

I/O Options

32-bit VESA local bus slots (3)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Reset switch

CN1

Turbo LED

CN4

Power LED & keylock

CN2

Turbo switch

CN5

Speaker

CN3

32 bit VESA local bus slots

SL1, SL2, SL3

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Factory configured - do not alter

J1

pins 1 & 2 closed

»

Fastgate A20 enabled

J2

pins 1 & 2 closed

 

Fastgate A20 disabled

J2

pins 2 & 3 closed

»

One or more ISA busmastering devices on ISA bus

J10

pins 1 & 2 closed

 

ISA busmastering system free

J10

pins 2 & 3 closed

»

Normal BIOS type operation

JP20

pins 1 & 2 closed

 

Flash EPROM type BIOS enabled

JP20

pins 2 & 3 closed

»

Graphic accelerator cards without Weitek P9x00

JP21

pins 1 & 2 closed

 

Graphic accelerator card with Weitek P9x00

JP21

pins 2 & 3 closed

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

1MB

(1) 256K x 36

NONE

NONE

NONE

2MB

(1) 512K x 36

NONE

NONE

NONE

2MB

(1) 256K x 36

(1) 256K x 36

NONE

NONE

4MB

(1) 1M x 36

NONE

NONE

NONE

4MB

(1) 512K x 36

NONE

(1) 512K x 36

NONE

8MB

(1) 2M x 36

NONE

NONE

NONE

8MB

(1) 1M x 36

(1) 1M x 36

NONE

NONE

16MB

(1) 4M x 36

NONE

NONE

NONE

16MB

(1) 2M x 36

NONE

(1) 2M x 36

NONE

32MB

(1) 8M x 36

NONE

NONE

NONE

32MB

(1) 4M x 36

NONE

(1) 4M x 36

NONE

64MB

(1) 8M x 36

NONE

(1) 8M x 36

NONE

64MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

CACHE CONFIGURATION (WRITE-THROUGH CACHE)

Size

Bank 0

Bank 1

WTTAG

WBTAG

64KB

(4) 8K x 8

(4) 8K x 8

NONE

(1) 8K x 8

128KB

(4) 32K x 8

NONE

NONE

(1) 32K x 8

256KB

(4) 32K x 8

(4) 32K x 8

NONE

(1) 32K x 8

512KB

(4) 128K x 8

NONE

NONE

(1) 32K x 8

1M

(4) 128K x 8

(4) 128K x 8

NONE

(1) 128K x 8

CACHE CONFIGURATION (WRITE-BACK CACHE)

Size

Bank 0

Bank 1

WTTAG

WBTAG

64KB

(4) 8K x 8

(4) 8K x 8

(1) 8K x 8

(1) 8K x 8

128KB

(4) 32K x 8

NONE

(1) 32K x 8

(1) 32K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

(1) 32K x 8

512KB

(4) 128K x 8

NONE

(1) 32K x 8

(1) 32K x 8

1M

(4) 128K x 8

(4) 128K x 8

(1) 128K x 8

(1) 128K x 8

CACHE JUMPER CONFIGURATION

Size

JS1

JS2

JS3

JS4

JS5

JS6

64KB

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

128KB

2 & 3

2 & 3

1 & 2

1 & 2

1 & 2

1 & 2

256KB

2 & 3

2 & 3

2 & 3

1 & 2

1 & 2

1 & 2

512KB

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

1 & 2

1MB

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

2 & 3

Note:Pins designated should be in the closed position.

CPU TYPE CONFIGURATION

CPU Type

Speed

JC1

JC2

JC3

JK1

JK2

80486SX

20MHz

2 & 3

2 & 3

Open

1 & 2

1 & 2

80486SX

25MHz

2 & 3

2 & 3

Open

1 & 2

1 & 2

80486SX

33MHz

2 & 3

2 & 3

Open

1 & 2

1 & 2

80487SX

25MHz

1 & 2

1 & 2

2 & 3

1 & 2

1 & 2

80486DX

25MHz

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

80486DX

33MHz

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

80486DX

40MHz

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

80486DX

50MHz

1 & 2

1 & 2

1 & 2

2 & 3

2 & 3

80486DX2

50iMHz

1 & 2

1 & 2

1 & 2

1 & 2

1 & 2

80486DX2

66iMHz

1 & 2

1 & 2

2 & 3

1 & 2

1 & 2

Note:Pins designated should be in the closed position.

CPU TYPE CONFIGURATION (CON’T)

CPU Type

Speed

JV1

JV2

JK3A1

JK3B1

80486SX

20MHz

2 & 3

1 & 2

Closed

Closed

80486SX

25MHz

2 & 3

1 & 2

Open

Closed

80486SX

33MHz

2 & 3

1 & 2

Closed

Open

80487SX

25MHz

2 & 3

1 & 2

Open

Closed

80486DX

25MHz

2 & 3

1 & 2

Open

Closed

80486DX

33MHz

2 & 3

2 & 3

Closed

Open

80486DX

40MHz

2 & 3

2 & 3

Open

Open

80486DX

50MHz

2 & 3

1 & 2

Open

Closed

80486DX2

50iMHz

2 & 3

1 & 2

Open

Open

80486DX2

66iMHz

2 & 3

1 & 2

Closed

Closed

Note:Pins designated should be in the closed position.