SOYO COMPUTER CO., LTD.

486 VESA GREEN MAINBOARD

Processor        CX486S/80486SX/CX486DX/80486DX/80486DX2/Pentium Overdrive
Processor Speed  25/33/40/50(internal)/50/66(internal)MHz
Chip Set         Unidentified
Max. Onboard     128MB
DRAM
Cache            64/128/256KB
BIOS             AMI
Dimensions       254mm x 220mm
I/O Options      32-bit VESA local bus slots (2), green PC connector
NPU Options      None

[Image]

                                CONNECTIONS

  Purpose                  Location    Purpose                  Location

  Green PC connector          J4       Turbo switch               J21

  Power LED & keylock        J17       Turbo LED                  J22

  Speaker                    J18       Green PC connector         JP28

  Reset switch               J19       Green PC connector         JP34

  External battery           J20       32-bit VESA local bus   SL1 & SL2
                                       slots

                        USER CONFIGURABLE SETTINGS

                Function                      Jumper         Position

  »   Monitor type select monochrome           JP3             Open

      Monitor type select color/EGA/VGA        JP3            Closed

  »   CMOS memory normal operation             JP5           pins 1 & 2
                                                              closed

      CMOS memory clear                        JP5           pins 2 & 3
                                                              closed

  »   CPU type select PGA                      JP18           Closed

      CPU type select PQFP                     JP18            Open

  »   Factory configured - do not alter        JP23            Open

  »   Factory configured - do not alter        JP31            Open

  »   Factory configured - do not alter        JP32            Open

  »   Factory configured - do not alter        JP35            Open

  »   Factory configured - do not alter        JP36            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

      17MB        (4) 256K x 9    (4) 4M x 9

      20MB        (4) 1M x 9      (4) 4M x 9

      32MB        (4) 4M x 9      (4) 4M x 9

      64MB        (4) 16M x 9        NONE

      68MB        (4) 1M x 9     (4) 16M x 9

      80MB        (4) 4M x 9     (4) 16M x 9

     128MB        (4) 16M x 9    (4) 16M 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) 32K x 8

                        CACHE JUMPER CONFIGURATION

      Size              JP24               JP25               JP26

      64KB              Open            pins 1 & 2            Open
                                          closed

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

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

                          CPU TYPE CONFIGURATION

       Type          JP1       JP4        JP6          JP8         JP9

     CX486SX        1 & 2     2 & 3       Open         Open       2 & 3

     80486SX        2 & 3     1 & 2      Closed        Open       2 & 3

     CX486DX        1 & 2     2 & 3       Open        Closed      1 & 2

     80486DX        2 & 3     1 & 2      Closed       Closed      1 & 2

     80486DX2       2 & 3     1 & 2      Closed       Closed      1 & 2

      Pentium       1 & 2     1 & 2       Open        Closed      1 & 2
    Overdrive

  Note: Pins designated should be in the closed position.

                      CPU TYPE CONFIGURATION (CON’T)

        Type            JP10          JP11         JP12          JP13

      CX486SX           2 & 3        2 & 3         2 & 3         Open

      80486SX           4 & 5         Open         Open          Open

      CX486DX           2 & 3        2 & 3         2 & 3         2 & 3

      80486DX           4 & 5         Open         Open          Open

      80486DX2          4 & 5         Open         Open          Open

       Pentium          1 & 2        1 & 2         1 & 2         1 & 2
     Overdrive

  Note: Pins designated should be in the closed position.

                      CPU TYPE CONFIGURATION (CON’T)

        Type            JP16          JP17         JP29          JP33

      CX486SX         1 & 2, 3 &   1 & 2, 3 &      2 & 3         2 & 3
                          4            4

      80486SX           2 & 3        2 & 3         1 & 2         2 & 3

      CX486DX         1 & 2, 3 &   1 & 2, 3 &      1 & 2         2 & 3
                          4            4

      80486DX           2 & 3        2 & 3         1 & 2         2 & 3

      80486DX2          2 & 3        2 & 3         1 & 2         2 & 3

       Pentium          2 & 3        2 & 3         1 & 2         1 & 2
     Overdrive

  Note: Pins designated should be in the closed position.

                          CPU SPEED CONFIGURATION

         Speed                JP20             JP21             JP22

         25MHz               Closed            Open            Closed

         33MHz                Open            Closed           Closed

         40MHz               Closed            Open             Open

         50MHz                Open            Closed            Open

     50MHz (Pentium          Closed            Open            Closed
    Overdrive only)

         50iMHz              Closed            Open            Closed

         66iMHz               Open            Closed           Closed