
GIGA-BYTE TECHNOLOGY CO., LTD.

GA-486AM/AMS (REV. 2.20)

Processor  CX486/AM486/UMC/SL80486SX/80486SX/SL80486DX/80486DX/
           SL80486DX2/80486DX2/P24D/AM486DX4/80486DX4/Pentium Overdrive
Processor  25/33/40/50(internal)/50/66(internal)/75(internal)/100(internal)MHz
Speed
Chip Set   UMC
Max.       128MB
Onboard
DRAM
Cache      128/256/512/1024KB
BIOS       Award
Dimensions 250mm x 220mm
I/O        32-bit PCI slots (3), floppy drive interface, green PC connector,
Options    IDE interfaces (2), parallel port, serial ports (2)
NPU        None
Options

[Image]

                                CONNECTIONS

  Purpose                  Location    Purpose                  Location

  IDE interface 1            CN1       Speaker                     J3

  IDE interface 2            CN2       Power LED & keylock         J4

  Floppy drive interface     CN3       IDE interface LED          JP1

  Parallel port              CN4       Turbo LED                  JP2

  Serial port 2              CN5       Green PC connector         JP3

  Serial port 1              CN6       Green PC LED               JP4

  Reset switch                J1       Green PC connector         JP25

  Turbo switch                J2       32-bit PCI slots         PC1 - PC3

                        USER CONFIGURABLE SETTINGS

                Function                     Jumper          Position

     Factory configured - do not             JP14          Pins 1 & 2
      alter                                                   closed

     Factory configured - do not             JP18          Pins 2 & 3
      alter                                                   closed

     Factory configured - do not             JP19            Closed
      alter

     Cache type select write through         JP20            Closed

      Cache type select write back            JP20             Open

                DRAM CONFIGURATION

      Size            Bank 0           Bank 1

       2MB        (2) 256K x 36         NONE

       4MB        (2) 512K x 36         NONE

       4MB        (2) 256K x 36    (2) 256K x 36

       6MB        (2) 512K x 36    (2) 256K x 36

       8MB        (2) 512K x 36    (2) 512K x 36

       8MB         (2) 1M x 36          NONE

      10MB         (2) 1M x 36     (2) 256K x 36

      12MB         (2) 1M x 36     (2) 512K x 36

      16MB         (2) 1M x 36      (2) 1M x 36

      16MB         (2) 2M x 36          NONE

      18MB         (2) 2M x 36     (2) 256K x 36

      20MB         (2) 2M x 36     (2) 512K x 36

      24MB         (2) 2M x 36      (2) 1M x 36

      32MB         (2) 2M x 36      (2) 2M x 36

      32MB         (2) 4M x 36          NONE

      34MB         (2) 4M x 36     (2) 256K x 36

      36MB         (2) 4M x 36     (2) 512K x 36

      40MB         (2) 4M x 36      (2) 1M x 36

      48MB         (2) 4M x 36      (2) 2M x 36

      64MB         (2) 4M x 36      (2) 4M x 36

      64MB         (2) 8M x 36          NONE

      66MB         (2) 8M x 36     (2) 256K x 36

      68MB         (2) 8M x 36     (2) 512K x 36

      72MB         (2) 8M x 36      (2) 1M x 36

      80MB         (2) 8M x 36      (2) 2M x 36

      96MB         (2) 8M x 36      (2) 4M x 36

      128MB        (2) 8M x 36      (2) 8M x 36

                      CACHE CONFIGURATION

      Size          Bank 0          Bank 1           TAG

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

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

   256KB (B)      (4) 64K x 8        NONE        (1) 16K x 8

   512KB (A)      (4) 64K x 8     (4) 64K x 8    (1) 32K x 8

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

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

                        CACHE JUMPER CONFIGURATION

         Size                     JP24                     JP26

         128KB                    Open               Pins 3 & 5 closed

       256KB (A)           Pins 1 & 2 closed         Pins 1 & 3 closed

       256KB (B)           Pins 1 & 2 closed         Pins 3 & 5 closed

       512KB (A)            Pins 1 & 2, 3 & 4        Pins 2 & 4 closed
                                 closed

       512KB (B)            Pins 1 & 2, 3 & 4        Pins 3 & 5 closed
                                 closed

          1MB            Pins 1 & 2, 3 & 4, 5 &      Pins 4 & 6 closed
                                6 closed

                          CPU TYPE CONFIGURATION

  Type       RN1          RN2           RN3          RN4          RN5

  Cyrix   Installed        Not          Not       Installed        Not
                       installed     installed                 installed

  AMD         Not      Installed        Not          Not       Installed
          installed                  installed    installed

  UMC         Not          Not       Installed       Not           Not
          installed    installed                  installed    installed

  Intel       Not      Installed        Not          Not       Installed
          installed                  installed    installed

          CPU TYPE CONFIGURATION

        Type                 JP8

    All CPU types     Pins 1 & 2 closed

   Intel S-series     Pins 3 & 4 closed

    AMD S-series      Pins 3 & 4 closed

      CPU TYPE CONFIGURATION

      Type             JP9

  All CPU types       Closed

       AMD             Open

       UMC             Open

          CPU TYPE CONFIGURATION

        Type                 JP11

       80486SX        Pins 2 & 3 closed

       80486DX        Pins 1 & 2 closed

      CPU TYPE CONFIGURATION

      Type             JP13

  All CPU types       Closed

    80486DX4           Open

                 CPU TYPE CONFIGURATION

            Type                        JP5

           Cyrix             Pins 1 & 2, 3 & 4 closed

            AMD              Pins 3 & 4, 5 & 6 closed

            UMC              Pins 5 & 6, 7 & 8 closed

           Intel             Pins 3 & 4, 5 & 6 closed

                       CPU SPEED CONFIGURATION

               Speed                              JP15

               25MHz                       Pins 1 & 2 closed

               33MHz                Pins 1 & 2, 3 & 4, 5 & 6 closed

               40MHz                    Pins 1 & 2, 3 & 4 closed

              50iMHz                       Pins 1 & 2 closed

               50MHz                       Pins 5 & 6 closed

              66iMHz                Pins 1 & 2, 3 & 4, 5 & 6 closed

              75iMHz                       Pins 1 & 2 closed

              100iMHz               Pins 1 & 2, 3 & 4, 5 & 6 closed

  CPU SPEED CONFIGURATION (P24D & AM486DX4 ONLY)

          Speed                     JP12

           2x                Pins 2 & 3 closed

           3x                Pins 1 & 2 closed

  CPU SPEED CONFIGURATION (80486DX4 ONLY)

        Speed                  JP10

          2x                  Closed

          3x                   Open

   CPU VOLTAGE CONFIGURATION

  Voltage     JP21      JP22

   3.3v       Open      Open

    4v        Open     Closed

    5v       Closed     Open

