BIOSTAR MICROTECH INTERNATIONAL CORPORATION

MB1420PD/1420PL/1425PD/1425PL/1433PD/

1433PL/1450PD/1450PL/1450E

Processor         80486SX/80486DX
Processor Speed   20/25/33/50MHz
Chip Set          OPTI
Max. Onboard DRAM 40MB
Cache             64/128/256KB
BIOS              AMI
Dimensions        330mm x 218mm
I/O Options       None
NPU Options       4167

[Image]

                                CONNECTIONS

  Purpose                   Location    Purpose                  Location

  External battery            J11       Turbo LED                 JP11

  Power LED & keylock         J20       Reset switch               SW1

  Speaker                     J21       Turbo switch               SW2

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

  »   CMOS memory normal operation             JP1           pins 2 & 3
                                                              closed

      CMOS memory clear                        JP1           pins 1 & 2
                                                              closed

  »   Monitor type select color                JP2            Closed

      Monitor type select monochrome           JP2             Open

                            DRAM CONFIGURATION

     Size         Bank 0         Bank 1         Bank 2          Bank 3

     1MB        (4) 256K x 9      NONE           NONE            NONE

     2MB        (4) 256K x 9   (4) 256K x 9      NONE            NONE

     4MB        (4) 1M x 9        NONE           NONE            NONE

     5MB        (4) 256K x 9   (4) 1M x 9        NONE            NONE

     6MB        (4) 256K x 9    (1) 256K x    (4) 1M x 9         NONE
                                   36

     8MB        (4) 1M x 9     (4) 1M x 9        NONE            NONE

     9MB        (4) 256K x 9   (4) 1M x 9     (1) 1M x 36        NONE

     10MB       (4) 256K x 9   (4) 256K x 9   (1) 1M x 36    (1) 1M x 36

     12MB       (4) 1M x 9     (4) 1M x 9     (1) 1M x 36        NONE

     13MB       (4) 256K x 9   (4) 1M x 9     (1) 1M x 36    (1) 1M x 36

     16MB       (4) 1M x 9     (4) 1M x 9     (1) 1M x 36    (1) 1M x 36

     16MB       (4) 4M x 9        NONE           NONE            NONE

     20MB       (4) 1M x 9     (4) 4M x 9        NONE            NONE

     20MB       (4) 4M x 9     (4) 1M x 9        NONE            NONE

     24MB       (4) 1M x 9     (4) 4M x 9     (1) 1M x 36        NONE

     24MB       (4) 1M x 9     (4) 4M x 9      (1) 256K x        NONE
                                                  36

     24MB       (4) 4M x 9     (4) 1M x 9     (1) 1M x 36        NONE

     28MB       (4) 4M x 9     (4) 1M x 9     (1) 1M x 36    (1) 1M x 36

     32MB       (4) 4M x 9     (4) 4M x 9        NONE            NONE

     36MB       (4) 4M x 9     (4) 4M x 9     (1) 1M x 36        NONE

     40MB       (4) 4M x 9     (4) 4M x 9     (1) 1M x 36    (1) 1M x 36

  Note:36-bit SIMM banks 2 & 3 are not installed on some board versions.

                            CACHE CONFIGURATION

     Size         Bank 0        Bank 1       TAG (U34)        Dirty Bit
                                                                (U46)

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

     128KB      (4) 32K x 8      NONE        (1) 8K x 8      (1) 64K x 1

     256KB      (4) 32K x 8   (4) 32K x 8   (1) 32K x 8      (1) 64K x 1

                        CACHE JUMPER CONFIGURATION

    Size       JP8         JP9         JP10        JP12          JP13

    64KB       Open       Open         Open        Open       pins 2 & 3
                                                                closed

   128KB       Open       Open        Closed      Closed      pins 1 & 2
                                                                closed

   256KB       Open      Closed       Closed      Closed      pins 2 & 3
                                                                closed

                          CPU TYPE CONFIGURATION

       Type               JP3               JP4                JP5

      80486SX             Open              Open            pins 2 & 3
                                                             closed

      80486DX          pins 2 & 3          Closed           pins 1 & 2
                         closed                              closed

         CPU SPEED CONFIGURATION

        Speed                JP7

        20MHz         pins 2 & 3 closed

        25MHz         pins 2 & 3 closed

        33MHz         pins 2 & 3 closed

        50MHz         pins 1 & 2 closed