
FOREX COMPUTER CORPORATION

386/486 CACHE SYSTEM BOARD

Processor        80386DX/CX486DLC/80486SX/80487SX/80486DX/80486DX2
Processor Speed  20/25/33/40/50(internal)/50/66(internal) MHz
Chip Set         Forex
Max. onboard DRAM32MB
Cache            64/128/256KB
BIOS             AMI
Dimensions       330mm x 218mm
I/O Options      32-bit local bus slot
NPU Options      80387DX

[Image]

                                CONNECTIONS

  Purpose                   Location    Purpose                  Location

  External battery            JP2       Speaker                   JP10

  Reset switch                JP8       Turbo switch              JP15

  Power LED & keylock         JP9       32-bit Local bus slot      S1

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

     Factory configured - do not alter        JP5              N/A

     CMOS memory normal operation             JP6            Closed

      CMOS memory clear                        JP6             Open

              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    (2) 8K x 8

                        CACHE JUMPER CONFIGURATION

    Size         JP8A        JP8B        JP8C        JP8E         JP8F

    64KB       pins 2 &     pins 1 &    pins 1 &    pins 2 &   pins 1 & 2
                  3            2           2           3

    128KB      pins 1 &     pins 2 &    pins 2 &    pins 1 &   pins 1 & 2
                  2            3           3           2

    256KB      pins 2 &     pins 1 &    pins 1 &    pins 1 &   pins 2 & 3
                  3            2           2           2

  Note:Pins designated should be in the closed position.

                          CPU SPEED CONFIGURATION

    Speed         JP7A            JP7B           JP7C           JP7D

    20MHz       pins 2 & 3     pins 1 & 2     pins 1 & 2      pins 2 & 3
                 closed          closed         closed         closed

    25MHz       pins 1 & 2     pins 2 & 3     pins 1 & 2      pins 2 & 3
                 closed          closed         closed         closed

    33MHz       pins 1 & 2     pins 1 & 2     pins 2 & 3      pins 2 & 3
                 closed          closed         closed         closed

    40MHz       pins 2 & 3     pins 2 & 3     pins 1 & 2      pins 2 & 3
                 closed          closed         closed         closed

    50MHz       pins 2 & 3     pins 1 & 2     pins 2 & 3      pins 2 & 3
                 closed          closed         closed         closed

    66MHz       pins 1 & 2     pins 1 & 2     pins 2 & 3      pins 1 & 2
                 closed          closed         closed         closed

    80MHz       pins 2 & 3     pins 2 & 3     pins 1 & 2      pins 1 & 2
                 closed          closed         closed         closed

                          CPU TYPE CONFIGURATION

      Type          W1B      W1A - W1G     W2A         W2A         W2C -
                                                                   W2H

    80386DX       pins 2 &    pins 2 &   pins 2 &    pins 2 &    pins 2 &
                     3           3          3           3           3

    CX486DLC      pins 2 &    pins 2 &   pins 2 &    pins 2 &    pins 2 &
                     3           3          3           3           3

     80486        pins 1 &    pins 1 &   pins 1 &    pins 1 &    pins 1 &
                     2           2          2           2           2

            Notes:Pins designated should be in the closed position.

                       80486 CPU TYPE CONFIGURATION

       Type               JP12              JP13               JP30

      80486SX          pins 2 & 3         pins 2 & 3        pins 2 & 3
                         closed            closed             closed

      80487SX          pins 1 & 2         pins 2 & 3        pins 2 & 3
                         closed            closed             closed

      80486DX          pins 1 & 2         pins 1 & 2        pins 1 & 2
                         closed            closed             closed

     80486DX2          pins 1 & 2         pins 1 & 2        pins 1 & 2
                         closed            closed             closed

