
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

[Image]

                                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    SL1  SL3
                                      slots

  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        Pins 1 & 2      Pins 2 & 3 closed
                       closed             closed

      128KB           Pins 1 & 2        Pins 2 & 3      Pins 1 & 2 closed
                       closed             closed

      256KB           Pins 1 & 2        Pins 1 & 2      Pins 1 & 2 closed
                       closed             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     Pins 2 & 3    Pins 2 & 3     Pins 1 & 2
                    closed        closed         closed         closed

    80487SX       Pins 2 & 3     Pins 1 & 2    Pins 1 & 2     Pins 1 & 2
                    closed        closed         closed         closed

     80486DX      Pins 2 & 3     Pins 2 & 3    Pins 2 & 3     Pins 1 & 2
     (PQFP)         closed        closed         closed         closed

     80486DX      Pins 1 & 2     Pins 1 & 2    Pins 1 & 2     Pins 1 & 2
     (PGA)          closed        closed         closed         closed

    80486DX2      Pins 1 & 2     Pins 1 & 2    Pins 1 & 2     Pins 1 & 2
                    closed        closed         closed         closed

      P23T        Pins 2 & 3     Pins 1 & 2    Pins 1 & 2     Pins 1 & 2
                    closed        closed         closed         closed

      P24T        Pins 1 & 2     Pins 1 & 2    Pins 1 & 2     Pins 2 & 3
                    closed        closed         closed         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

