
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       128MB (EDO supported)
Memory
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

[Image]

                                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               J11
                                       interface

  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           J6           Unidentified
      alter

     Factory configured - do not           JP4          Unidentified
      alter

     Factory configured - do not           JP5          Unidentified
      alter

     Factory configured - do not           JP6          Unidentified
      alter

     Factory configured - do not           JP7          Unidentified
      alter

     Factory configured - do not           JP9              Open
      alter

     Factory configured - do not          JP15          Unidentified
      alter

     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          JP26          Unidentified
      alter

     Factory configured - do not          JP27          Unidentified
      alter

     Factory configured - do not          JP28          Unidentified
      alter

     Factory configured - do not          JP29          Unidentified
      alter

     Factory configured - do not          JP30          Unidentified
      alter

     Factory configured - do not          JP31          Unidentified
      alter

     Factory configured - do not          JP32          Unidentified
      alter

     Factory configured - do not          JP33          Unidentified
      alter

     Factory configured - do not          JP34          Unidentified
      alter

     Factory configured - do not          JP35          Unidentified
      alter

     Factory configured - do not          JP36          Unidentified
      alter

     Factory configured - do not          JP37          Unidentified
      alter

                    USER CONFIGURABLE SETTINGS (CONT)

               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          JP39             Closed
      CLK

      PCICLK speed select = 32MHz          JP39              Open

     PS/2 IRQ12 enabled                   JP41             Closed

      PS/2 IRQ12 disabled                  JP41              Open

     Factory configured - do not          JP42          Unidentified
      alter

                           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         Pins 1 & 2            Open
                       closed              closed

    256KB (B)         Pins 1 & 2         Pins 1 & 2            Open
                       closed              closed

    512KB (A)         Pins 2 & 3            Open              Closed
                       closed

    512KB (B)         Pins 2 & 3         Pins 1 & 2            Open
                       closed              closed

       1MB            Pins 2 & 3         Pins 2 & 3            Open
                       closed              closed

                            CPU SPEED SELECTION

    CPU      Clock    Multiplier     JP12      JP13      JP18      JP19
  speed     speed

  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       Pins 2 & 3          Open             Open
            card             closed

