VEXTREC TECHNOLOGY, INC.

GMB-486UN (VER. 3.00)

Device Type            Mainboard
Processor              80486SX/80486DX/80486DX2
Processor Speed        25/33/50/66MHz
Chip Set               Unidentified
Maximum Onboard Memory 32MB DRAM
Cache                  32/64/128/256KB
BIOS                   Acer
I/O Options            None

[Image]

                           CONNECTIONS

  External battery        JP1     Turbo LED               JP16

  Reset switch           JP14     Speaker                 JP17

  Turbo switch           JP15     Power LED & keylock     JP18

                        USER CONFIGURABLE SETTINGS

                Function                     Label           Position

  »   CMOS memory normal operation            JP2           Pins 1 & 2
                                                              closed

      CMOS memory clear                       JP2           Pins 2 & 3
                                                              closed

  »   Hardware emulate KBGA20                 JP10          Pins 1 & 2
                                                              closed

      Keyboard controller 8042                JP10          Pins 2 & 3
                                                              closed

  »   Color display enabled                   JP12            Closed

      Monochrome display enabled              JP12             Open

                DRAM CONFIGURATION

      Size            Bank 0           Bank 1

       1MB        (4) 256KB x 9         None

       2MB        (4) 256KB x 9    (4) 256KB x 9

       4MB         (4) 1MB x 9          None

       5MB         (4) 1MB x 9     (4) 256KB x 9

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

      16MB         (4) 4MB x 9          None

      17MB         (4) 4MB x 9     (4) 256KB x 9

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

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

                     CACHE CONFIGURATION

    Size          Bank 0           Bank 1           TAG

    32KB        (4) 8K x 8          None         (1) 8K x 8

    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          JP22            JP23           JP25           JP26

    32KB        Pins 2 & 3     Pins 2 & 3     Pins 1 & 2      Pins 2 & 3
                 closed          closed         closed         closed

    64KB        Pins 2 & 3     Pins 2 & 3     Pins 2 & 3      Pins 1 & 2
                 closed          closed         closed         closed

    128KB       Pins 2 & 3     Pins 1 & 2     Pins 2 & 3      Pins 2 & 3
                 closed          closed         closed         closed

    256KB       Pins 1 & 2     Pins 2 & 3     Pins 2 & 3      Pins 2 & 3
                 closed          closed         closed         closed

       CACHE JUMPER CONFIGURATION (CONT.)

   Size      JP27     JP28      JP29      JP30

   32KB     Closed    Open      Open      Open

   64KB      Open    Closed     Open      Open

  128KB      Open     Open     Closed     Open

  256KB      Open     Open      Open     Closed

                            CPU SPEED SELECTION

      Speed            JP3           JP7           JP9           JP13

      25MHz           2 & 3         Open          2 & 3         2 & 3

      33MHz           1 & 2         1 & 2       1 & 2, 3 &      1 & 2
                                                    4

    50MHz (DX)        2 & 3         1 & 2       1 & 2, 3 &      1 & 2
                                                    4

   50MHz (DX2)        1 & 2         1 & 2       1 & 2, 3 &      1 & 2
                                                    4

      66MHz           1 & 2         1 & 2       1 & 2, 3 &      1 & 2
                                                    4