
YOUNG MICRO SYSTEMS, INC.

486 EISA/VESA

Processor        80486SX/80486DX/80486DX2/Pentium Overdrive
Processor Speed  20/25/33/40/50/50(internal)/66(internal)/MHz
Chip Set         VIA
Max. Onboard DRAM64MB
Cache            64/128/256/512/1024KB
BIOS             AMI
Dimensions       330mm x 218mm
I/O Options      32-bit VESA local bus slots (3)
NPU Options      None

[Image]

                                CONNECTIONS

  Purpose                 Location     Purpose                Location

  Reset switch              CN1        Turbo LED                CN4

  Power LED & keylock       CN2        Turbo switch             CN5

  Speaker                   CN3        32 bit VESA local    SL1, SL2, SL3
                                       bus slots

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

     Factory configured - do not alter        J1            pins 1 & 2
                                                              closed

     Fastgate A20 enabled                     J2            pins 1 & 2
                                                              closed

      Fastgate A20 disabled                    J2            pins 2 & 3
                                                              closed

     One or more ISA busmastering             J10           pins 1 & 2
      devices on ISA bus                                      closed

      ISA busmastering system free             J10           pins 2 & 3
                                                              closed

     Normal BIOS type operation              JP20           pins 1 & 2
                                                              closed

      Flash EPROM type BIOS enabled           JP20           pins 2 & 3
                                                              closed

     Graphic accelerator cards without       JP21           pins 1 & 2
      Weitek P9x00                                            closed

      Graphic accelerator card with           JP21           pins 2 & 3
      Weitek P9x00                                            closed

                            DRAM CONFIGURATION

     Size         Bank 0         Bank 1         Bank 2          Bank 3

     1MB         (1) 256K x       NONE           NONE            NONE
                    36

     2MB         (1) 512K x       NONE           NONE            NONE
                    36

     2MB         (1) 256K x     (1) 256K x       NONE            NONE
                    36             36

     4MB        (1) 1M x 36       NONE           NONE            NONE

     4MB         (1) 512K x       NONE         (1) 512K x        NONE
                    36                            36

     8MB        (1) 2M x 36       NONE           NONE            NONE

     8MB        (1) 1M x 36    (1) 1M x 36       NONE            NONE

     16MB       (1) 4M x 36       NONE           NONE            NONE

     16MB       (1) 2M x 36       NONE        (1) 2M x 36        NONE

     32MB       (1) 8M x 36       NONE           NONE            NONE

     32MB       (1) 4M x 36       NONE        (1) 4M x 36        NONE

     64MB       (1) 8M x 36       NONE        (1) 8M x 36        NONE

     64MB       (1) 4M x 36    (1) 4M x 36    (1) 4M x 36    (1) 4M x 36

                 CACHE CONFIGURATION (WRITE-THROUGH CACHE)

     Size          Bank 0         Bank 1         WTTAG          WBTAG

     64KB        (4) 8K x 8     (4) 8K x 8       NONE        (1) 8K x 8

     128KB       (4) 32K x 8       NONE          NONE        (1) 32K x 8

     256KB       (4) 32K x 8    (4) 32K x 8      NONE        (1) 32K x 8

     512KB       (4) 128K x        NONE          NONE        (1) 32K x 8
                     8

      1M         (4) 128K x     (4) 128K x       NONE       (1) 128K x 8
                     8              8

                  CACHE CONFIGURATION (WRITE-BACK CACHE)

     Size          Bank 0         Bank 1         WTTAG          WBTAG

     64KB        (4) 8K x 8     (4) 8K x 8    (1) 8K x 8     (1) 8K x 8

     128KB       (4) 32K x 8       NONE       (1) 32K x 8    (1) 32K x 8

     256KB       (4) 32K x 8    (4) 32K x 8   (1) 32K x 8    (1) 32K x 8

     512KB       (4) 128K x        NONE       (1) 32K x 8    (1) 32K x 8
                     8

      1M         (4) 128K x     (4) 128K x     (1) 128K x   (1) 128K x 8
                     8              8              8

                  CACHE JUMPER CONFIGURATION

  Size      JS1     JS2      JS3      JS4      JS5      JS6

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

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

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

  512KB    2 & 3   2 & 3    2 & 3    2 & 3    2 & 3    1 & 2

   1MB     2 & 3   2 & 3    2 & 3    2 & 3    2 & 3    2 & 3

  Note:Pins designated should be in the closed position.

                          CPU TYPE CONFIGURATION

  CPU Type     Speed       JC1       JC2       JC3       JK1        JK2

  80486SX      20MHz      2 & 3     2 & 3     Open      1 & 2      1 & 2

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

  80486SX      33MHz      2 & 3     2 & 3     Open      1 & 2      1 & 2

  80487SX      25MHz      1 & 2     1 & 2     2 & 3     1 & 2      1 & 2

  80486DX      25MHz      1 & 2     1 & 2     1 & 2     1 & 2      1 & 2

  80486DX      33MHz      1 & 2     1 & 2     1 & 2     1 & 2      1 & 2

  80486DX      40MHz      1 & 2     1 & 2     1 & 2     1 & 2      1 & 2

  80486DX      50MHz      1 & 2     1 & 2     1 & 2     2 & 3      2 & 3

  80486DX2    50iMHz      1 & 2     1 & 2     1 & 2     1 & 2      1 & 2

  80486DX2    66iMHz      1 & 2     1 & 2     2 & 3     1 & 2      1 & 2

  Note:Pins designated should be in the closed position.

                   CPU TYPE CONFIGURATION (CONT)

  CPU Type     Speed       JV1         JV2        JK3A1      JK3B1

  80486SX      20MHz      2 & 3       1 & 2      Closed     Closed

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

  80486SX      33MHz      2 & 3       1 & 2      Closed      Open

  80487SX      25MHz      2 & 3       1 & 2       Open      Closed

  80486DX      25MHz      2 & 3       1 & 2       Open      Closed

  80486DX      33MHz      2 & 3       2 & 3      Closed      Open

  80486DX      40MHz      2 & 3       2 & 3       Open       Open

  80486DX      50MHz      2 & 3       1 & 2       Open      Closed

  80486DX2    50iMHz      2 & 3       1 & 2       Open       Open

  80486DX2    66iMHz      2 & 3       1 & 2      Closed     Closed

  Note:Pins designated should be in the closed position.

