MYLEX CORPORATION

MSI/MDI486 System Board

Processor            80486SX/80487SX/80486DX
Processor Speed      20/25/33MHz
Chip Set             OPTI
Max. Onboard DRAM    32MB
Cache                64/256KB
BIOS                 Mylex
Dimensions           330mm x 218mm
I/O Options          Floppy drive interface, IDE interface, parallel port,
                     serial ports (2)
NPU Options          4167

[Image]

                                CONNECTIONS

  Purpose                   Location   Purpose                   Location

  External battery            BAT      Turbo LED                   JP3

  Serial port 2              COM2      Reset switch                JP4

  Serial port 1              COM1      Speaker                     JP5

  Floppy drive interface      FDD      IDE interface LED           JP6

  IDE interface               IDE      Parallel port               LPT

  Power LED & keylock         JP2

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

  »   Monitor type select color                JP1            Closed

      Monitor type select monochrome           JP1             Open

  »   Parallel port select LPT1               JP19           pins 2 & 3
      interrupt IRQ7                                          closed

      Parallel port select LPT2               JP19           pins 1 & 2
      interrupt IRQ5                                          closed

  »   On-board interface ports enabled        JP20           pins 1 & 2
                                                              closed

      On-board interface ports disabled       JP20           pins 2 & 3
                                                              closed

  »   Battery type select internal            JP21           pins 2 & 3
                                                              closed

      Battery type select external            JP21             Open

      CMOS memory clear                       JP21           pins 1 & 2
                                                              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) 1M x 9     (4) 256K x 9

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

      16MB        (4) 4M x 9         NONE

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

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

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

                    CACHE CONFIGURATION

     Size          Bank 0       TAG (U19)      TAG (U20)

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

     256KB      (8) 32K x 8    (1) 32K x 8    (1) 64K x 1

           CACHE JUMPER CONFIGURATION

   Size      JP7      JP11      JP12      JP13

   64KB     Open      Open      Open      Open

  256KB    Closed    Closed     Open     Closed

                          CPU TYPE CONFIGURATION

       Type               JP8                JP9               JP10

      80486SX             Open            pins 2 & 3           Open
                                           closed

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

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

                          CPU SPEED CONFIGURATION

    Speed         JP14            JP15           JP16           JP17

    20MHz       pins 2 & 3     pins 1 & 2     pins 2 & 3      pins 1 & 2
                 closed          closed         closed         closed

    25MHz       pins 2 & 3     pins 2 & 3     pins 1 & 2      pins 2 & 3
                 closed          closed         closed         closed

    33MHz       pins 2 & 3     pins 1 & 2     pins 1 & 2      pins 2 & 3
                 closed          closed         closed         closed