
UNIDENTIFIED

STC-SIS486C-DX/SX

Processor         80486SX/80487SX/80486DX
Processor Speed   20/25/33/50MHz
Chip Set          SIS
Max. onboard DRAM 32MB
Cache             32/64/128/256KB
BIOS              AMI
Dimensions        218mm x 218mm
I/O Options       None
NPU Options       None

[Image]

                                CONNECTIONS

  Purpose                   Location    Purpose                  Location

  External battery             J1       Turbo LED                  J6

  Power LED & keylock          J3       Turbo switch               J7

  Speaker                      J4       Reset switch               J8

  Unknown                      J5

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

     CMOS memory normal operation             J1            pins 2 & 3
      (internal battery)                                      closed

      CMOS memory normal operation             J1            pins 1 & 4
      (external battery)                                      closed

      CMOS memory clear                        J1              Open

     Monitor type select color                J2             Closed

      Monitor type select monochrome           J2              Open

     CPU speed select iOSC/1                  J9            pins 1 & 2
                                                              closed

      CPU speed select iOSC/2                  J9            pins 2 & 3
                                                              closed

     Turbo switch enabled                     J10            Closed

      Turbo switch disabled                    J10             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

      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 (U26   Bank 1 (U22 -       Tag        Dirty Bit
                   - 29)           U25)

     32KB        (4) 8K x 8        NONE          8K x 8        16K x 4

     64KB        (4) 8K x 8     (4) 8K x 8       8K x 8        16K x 4

    128KB       (4) 32K x 8        NONE          32K x 8       16K x 4

    256KB       (4) 32K x 8     (4) 32K x 8      32K x 8       16K x 4

                        CACHE JUMPER CONFIGURATION

  Size     J11    J12     J13    J14    J15    J16    J17    J18     J19

  32KB     1 &    Open    1 &    1 &    1 &    1 &    1 &    1 &    1 & 2
            2              2      2      2      2      2      2

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

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

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

  Note:Pins designated should be in the closed position.

                          CPU TYPE CONFIGURATION

       Type               J20               J21                J22

      80486SX           Closed           pins 1 & 2         pins 1 & 2
                                          closed             closed

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

      80486DX            Open            pins 2 & 3           Open
                                          closed

