
SOYO COMPUTER CO., LTD.

486 MAINBOARD

Processor         80486SX/80487SX/80486DX/80486DX2
Processor Speed   20/25/33/50/66(internal)MHz
Chip Set          ETEQ
Max. Onboard DRAM 32MB
Cache             64/128/256KB
BIOS              AMI
Dimensions        240mm x 220mm
I/O Options       None
NPU Options       None

[Image]

                                CONNECTIONS

  Purpose                   Location   Purpose                   Location

  Power LED & keylock         J17      External battery            J20

  Speaker                     J18      Turbo switch                J21

  Reset switch                J19      Turbo LED                   J22

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

     Monitor type select monochrome           JP3             Open

      Monitor type select color                JP3            Closed

     CMOS memory normal operation             JP5           pins 1 & 2
                                                              closed

      CMOS memory clear                        JP5           pins 2 & 3
                                                              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

      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

                    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     JP21    JP22     JP23     JP24     JP25    JP26     JP27

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

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

  256KB    2 & 3    2 & 3    2 & 3   2 & 3    2 & 3    2 & 3    2 & 3

  Note: Pins designated should be in the closed position.

                          CPU TYPE CONFIGURATION

       Type           Crystal      JP9       JP11        JP12      JP13
                       OSC1

  80486SX-20MHz       40MHz       2 & 3      Open       2 & 3      2 & 3

  80486SX-25MHz       25MHz       1 & 2      Open       2 & 3      2 & 3

  80487SX-20MHz       40MHz       2 & 3     Closed      2 & 3      1 & 2

  80486DX-25MHz       25MHz       1 & 2     Closed      1 & 2      1 & 2

  80486DX-33MHz       33MHz       1 & 2     Closed      1 & 2      1 & 2

  80486DX-50MHz       50MHz       1 & 2     Closed      1 & 2      1 & 2

  80486DX2-50MHz      33MHz       1 & 2     Closed      1 & 2      1 & 2

  80486DX2-66MHz      33MHz       1 & 2     Closed      1 & 2      1 & 2

  Note: Pins designated should be in the closed position.

