
SOYO COMPUTER CO., LTD.

SY-025A2

Processor             80486SX/80487SX/80486DX/ODP486SX/80486DX2
Processor Speed       25/33/50(internal)/50/66(internal)MHz
Chip Set              SIS
Max. Onboard DRAM     32MB
Cache                 64/128/256KB
BIOS                  AMI
Dimensions            220mm x 254mm
I/O Options           32-bit VESA local bus slots (2)
NPU Options           None

[Image]

                                CONNECTIONS

  Purpose                Location      Purpose                Location

  Keylock                  J17         Turbo switch             J21

  Speaker                  J18         Turbo LED                J22

  Reset                    J19         32-bit VESA local      S1 & S2
                                       bus slots (2)

  External battery         J20

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

     Monitor type select color                JP3            Closed

      Monitor type select monochrome           JP3             Open

     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

      8MB         (4) 1M x 9      (4) 1M x 9

      16MB        (4) 4M x 9         NONE

      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                 JP6                  JP7

        64KB           pins 1 & 2 closed          open

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

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

                          CPU TYPE CONFIGURATION

      Type            JP13           JP14          JP15          JP16

  80486SX (PQFP)      Open         pins 2 & 3      Open          Open
                                    closed

  80486SX (PGA)       Open         pins 2 & 3      Open         Closed
                                    closed

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

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

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

                          CPU SPEED CONFIGURATION

   Speed       OSC at    JP8 - JP11      JP20        JP21         JP22
                 Y1

   25MHZ       25MHz      pins 1 & 2    Closed       Open        Closed
                           closed

   33MHz       33MHz      pins 1 & 2     Open       Closed       Closed
                           closed

   50iMHZ      25MHz      pins 1 & 2    Closed       Open        Closed
                           closed

   50MHz       50MHz      pins 2 & 3     Open       Closed        Open
                           closed

   66iMHz      33MHz      pins 1 & 2     Open       Closed       Closed
                           closed

  Notes:The board may come with a clock generator at Y1.

  JP8 controls VESA bus slot S1's speed, JP9 Controls VESA bus slot S1's
  wait states.

  JP10 controls VESA bus slot S2's speed, JP11 Controls VESA bus slot
  S2's wait states.

