ABIT COMPUTER CORPORATION

AT4

Processor              80486SX/80486DX/P23T
Processor Speed        16/25/33/50MHz
Chip Set               Unidentified
Video Chip Set         None
Maximum Onboard Memory 32MB
Maximum Video Memory   None
Cache                  32/64/128/256/512/1024KB
BIOS                   AMI
Dimensions             330mm x 218mm
I/O Options            None
NPU Options            4167

[Image]

                                CONNECTIONS

  Purpose                   Location    Purpose                  Location

  Speaker                     CN1       Turbo switch               JP1

  Power LED & keylock         CN2       Turbo LED                  JP2

  External battery            CN3       Reset switch               SW1

                        USER CONFIGURABLE SETTINGS

                Function                      Label          Position

  »   CMOS memory normal operation             JP5          Pins 1 & 2
                                                              closed

      CMOS memory clear                        JP5          Pins 2 & 3
                                                              closed

      Monitor type select CGA/EGA/VGA          JP7            Closed

      Monitor type select monochrome           JP7             Open

  »   Factory configured - do not alter        JP8             Open

  »   Factory configured - do not alter        JP9             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

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

                            CACHE CONFIGURATION

     Size          Bank 0         Bank 1          TAG            TAG0

     32KB        (4) 8K x 8        None        (1) 8K x 8    (2) 16K x 4

     64KB        (4) 8K x 8     (4) 8K x 8     (1) 8K x 8    (2) 16K x 4

     128KB       (4) 32K x 8       None        (1) 8K x 8    (2) 16K x 4

     256KB       (4) 32K x 8   (4) 32K x 8    (1) 32K x 8    (2) 16K x 4

     512KB       (4) 128K x 8      None       (1) 32K x 8    (2) 64K x 4

      1MB        (4) 128K x 8  (4) 128K x 8   (1) 128K x 8   (2) 64K x 4

  Note: Use either TAG chip or TAG0 chips. All three sockets can’t be
  installed at the same time.

                        CACHE JUMPER CONFIGURATION

    Size         JP3          JP4            JPX4              JPX5

    32KB         N/A          Open         Pins 1 - 8        Pins 1 - 8
                                           installed         installed

    64KB         N/A          Open        Pins 9 - 16       Pins 3 - 10
                                           installed         installed

   128KB         N/A         Closed        Pins 1 - 8       Pins 5 - 12
                                           installed         installed

   256KB         N/A         Closed       Pins 9 - 16       Pins 7 - 14
                                           installed         installed

   512KB         N/A         Closed        Pins 1 - 8       Pins 9 - 16
                                           installed         installed

    1MB        Closed        Closed       Pins 9 - 16       Pins 9 - 16
                                           installed         installed

                CPU TYPE SELECTION

      Type             JP6              JPX3

     80486SX          Closed       Not installed

     80486DX           Open          Installed

      P23T             Open          Installed