J-MARK COMPUTER CORPORATION

J-646B

Processor

Pentium

Processor Speed

75/90/100/120/133/150/166MHz

Chip Set

SIS

Video Chip Set

None

Maximum Onboard Memory

128MB (EDO supported)

Maximum Video Memory

None

Cache

256/512/1024KB

BIOS

Award

Dimensions

330mm x 218mm

I/O Options

32-bit PCI slots (3), floppy drive interface, IDE interfaces (2), parallel port, PS/2 mouse interface, serial ports (2)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Speaker

CN1

Serial port 2

J8

Reset switch

CN2

Serial port 1

J9

Turbo LED

CN3

Parallel port

J10

Power LED & keylock

CN4

Floppy drive interface

J11

Turbo switch

CN5

IDE interface 1

J12

IDE interface LED

CN6

IDE interface 2

J13

BK LED

CN7

External battery

J15

PS/2 mouse interface

J2

32-bit PCI slots

PC1 – PC3

VGA feature connector

J7

   

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

Factory configured - do not alter

J6

Unidentified

»

Factory configured - do not alter

JP4

Unidentified

»

Factory configured - do not alter

JP5

Unidentified

»

Factory configured - do not alter

JP6

Unidentified

»

Factory configured - do not alter

JP7

Unidentified

»

Factory configured - do not alter

JP9

Open

»

Factory configured - do not alter

JP15

Unidentified

»

CPU write select write back

JP16

Pins 1 & 2 closed

 

CPU write select write through

JP16

Pins 2 & 3 closed

»

CPU pipeline enabled

JP17

Pins 2 & 3 closed

 

CPU pipeline disabled

JP17

Pins 1 & 2 closed

»

Suspend mode disabled

JP20

Open

 

Suspend mode enabled

JP20

Closed

»

Break switch for suspend mode

JP24

Pins 2 & 3 closed

 

8042 RC enabled

JP24

Pins 1 & 2 closed

»

Monitor type select monochrome

JP25

Open

 

Monitor type select color

JP25

Closed

»

Factory configured - do not alter

JP26

Unidentified

»

Factory configured - do not alter

JP27

Unidentified

»

Factory configured - do not alter

JP28

Unidentified

»

Factory configured - do not alter

JP29

Unidentified

»

Factory configured - do not alter

JP30

Unidentified

»

Factory configured - do not alter

JP31

Unidentified

»

Factory configured - do not alter

JP32

Unidentified

»

Factory configured - do not alter

JP33

Unidentified

»

Factory configured - do not alter

JP34

Unidentified

»

Factory configured - do not alter

JP35

Unidentified

»

Factory configured - do not alter

JP36

Unidentified

»

Factory configured - do not alter

JP37

Unidentified

USER CONFIGURABLE SETTINGS (CON’T)

Function

Label

Position

»

CMOS memory normal operation

JP38

Pins 1 & 2 closed

 

CMOS memory clear

JP38

Pins 2 & 3 closed

»

PCICLK speed select 1/2 CPU CLK

JP39

Closed

 

PCICLK speed select = 32MHz

JP39

Open

»

PS/2 IRQ12 enabled

JP41

Closed

 

PS/2 IRQ12 disabled

JP41

Open

»

Factory configured - do not alter

JP42

Unidentified

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

4MB

(1) 1M x 36

None

None

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

(1) 2M x 36

None

None

16MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

24MB

(1) 1M x 36

(1) 1M x 36

(1) 2M x 36

(1) 2M x 36

32MB

(1) 8M x 36

None

None

None

32MB

(1) 4M x 36

(1) 4M x 36

None

None

32MB

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

40MB

(1) 4M x 36

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

48MB

(1) 4M x 36

(1) 4M x 36

(1) 2M x 36

(1) 2M x 36

64MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

72MB

(1) 8M x 36

(1) 8M x 36

(1) 1M x 36

(1) 1M x 36

80MB

(1) 8M x 36

(1) 8M x 36

(1) 2M x 36

(1) 2M x 36

96MB

(1) 8M x 36

(1) 8M x 36

(1) 4M x 36

(1) 4M x 36

128MB

(1) 8M x 36

(1) 8M x 36

(1) 8M x 36

(1) 8M x 36

Note: Board accepts EDO memory. Board also accepts x 32 SIMMs.

DRAM VOLTAGE CONFIGURATION

Voltage

JP1

»

Mixed mode

Pins 3 & 5, 4 & 6 closed

 

3.3v

Pins 1 & 3, 2 & 4 closed

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

256KB (A)

None

(8) 32K x 8

(1) 8K x 8

256KB (B)

(2) 32K x 32

None

Unidentified

512KB (A)

None

(8) 64K x 8

(1) 16K x 8 (Windbond)

512KB (B)

None

(8) 64K x 8

(1) 16K/32K x 8 (Aster)

1MB

None

(8) 128K x 8

(1) 32K x 8

Note: The location of bank 1 & TAG are unidentified.

CACHE JUMPER CONFIGURATION

Size

JP3

JP11

JP42

256KB (A)

Pins 1 & 2 closed

Pins 1 & 2 closed

Open

256KB (B)

Pins 1 & 2 closed

Pins 1 & 2 closed

Open

512KB (A)

Pins 2 & 3 closed

Open

Closed

512KB (B)

Pins 2 & 3 closed

Pins 1 & 2 closed

Open

1MB

Pins 2 & 3 closed

Pins 2 & 3 closed

Open

CPU SPEED SELECTION

CPU speed

Clock speed

Multiplier

JP12

JP13

JP18

JP19

75MHz

50MHz

1.5x

Closed

Closed

Open

Open

90MHz

60MHz

1.5x

Closed

Open

Open

Open

100MHz

66MHz

1.5x

Open

Closed

Open

Open

120MHz

60MHz

2x

Closed

Open

Open

Closed

133MHz

66MHz

2x

Open

Closed

Open

Closed

150MHz

60MHz

2.5x

Closed

Open

Closed

Closed

166MHz

66MHz

2.5x

Open

Closed

Closed

Closed

CPU VOLTAGE SELECTION

Voltage

JP21

JP22

JP23

 

3.3v

Closed

Open

Open

»

3.45v

Open

Closed

Open

 

3.6v

Open

Open

Closed

VGA SELECTION

Setting

JP2

JP8

JP10

»

Onboard VGA

Pins 1 & 2 closed

Closed

Closed

 

External VGA card

Pins 2 & 3 closed

Open

Open