
ABIT COMPUTER CORPORATION

PB4 (REV.1.2)

Processor  80486SX/SL AM486DX/80486DX/CX486DX2/AM486DX2/80486DX2/
           AM486DX4/CX486DX4/80486DX4/CX M1/P24D/Pentium Overdrive
Processor  25/33/40/50(internal)/66(internal)/75(internal)/80(internal)/100(internal)/
Speed      120(internal)MHz
Chip Set   Unidentified
Max.       64MB
Onboard
DRAM
Cache      128/256KB
BIOS       Award
Dimensions 220mm x 220mm
I/O        32-bit PCI slots (3), floppy drive interface, green PC connector, IDE
Options    interfaces (2), parallel port, serial ports (2), PISA slot
NPU        None
Options

[Image]

                                CONNECTIONS

  Purpose                   Location    Purpose                 Location

  Floppy drive interface      CN1       External battery          JP18

  Parallel port               CN2       Power LED & keylock       JW1

  IDE interface 2             CN3       Speaker                   JW2

  IDE interface 1             CN4       Turbo LED                 JW3

  Serial port 2                J3       Turbo switch              JW4

  Serial port 1                J4       Reset switch              JW5

  Green PC connector          JP13      32-bit PCI slots        PC1 - PC3

  IDE interface LED           JP16      PISA slot                 SL1

                        USER CONFIGURABLE SETTINGS

                Function                    Jumper           Position

     Factory configured - do not            JP12           pins 1 & 2
      alter                                                   closed

     Factory configured - do not            JP14              Open
      alter

     BIOS type select 5v EPROM              JP15         pins 2 & 3, 4 &
                                                             5 closed

      BIOS type select 12v flash             JP15         pins 1 & 2, 5 &
                                                             6 closed

     CMOS memory normal operation           JP17           pins 1 & 2
                                                              closed

      CMOS memory clear                      JP17           pins 2 & 3
                                                              closed

  Note: The location of jumpers JP12 and JP14 are unidentified.

                DRAM CONFIGURATION

      Size            Bank 0           Bank 1

       1MB        (1) 256K x 36         NONE

       2MB        (1) 512K x 36         NONE

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

       3MB        (1) 256K x 36    (1) 512K x 36

       3MB        (1) 512K x 36    (1) 256K x 36

       4MB         (1) 1M x 36          NONE

       4MB        (1) 512K x 36    (1) 512K x 36

       5MB        (1) 256K x 36     (1) 1M x 36

       5MB         (1) 1M x 36     (1) 256K x 36

       6MB        (1) 512K x 36     (1) 1M x 36

       6MB         (1) 1M x 36     (1) 512K x 36

       8MB         (1) 2M x 36          NONE

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

       9MB        (1) 256K x 36     (1) 2M x 36

       9MB         (1) 2M x 36     (1) 256K x 36

      10MB        (1) 512K x 36     (1) 2M x 36

      10MB         (1) 2M x 36     (1) 512K x 36

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

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

      16MB         (1) 4M x 36          NONE

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

      17MB        (1) 256K x 36     (1) 4M x 36

      17MB         (1) 4M x 36     (1) 256K x 36

      18MB        (1) 512K x 36     (1) 4M x 36

      18MB         (1) 4M x 36     (1) 512K x 36

      20MB         (1) 1M x 36      (1) 4M x 36

      20MB         (1) 4M x 36      (1) 1M x 36

      24MB         (1) 2M x 36      (1) 4M x 36

      24MB         (1) 4M x 36      (1) 2M x 36

      32MB         (1) 8M x 36          NONE

      32MB         (1) 4M x 36      (1) 4M x 36

      33MB        (1) 256K x 36     (1) 8M x 36

      33MB         (1) 8M x 36     (1) 256K x 36

            DRAM CONFIGURATION (CONT)

      Size            Bank 0           Bank 1

      34MB        (1) 512K x 36     (1) 8M x 36

      34MB         (1) 8M x 36     (1) 512K x 36

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

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

      40MB         (1) 2M x 36      (1) 8M x 36

      40MB         (1) 8M x 36      (1) 2M x 36

      48MB         (1) 4M x 36      (1) 8M x 36

      48MB         (1) 8M x 36      (1) 4M x 36

      64MB         (1) 8M x 36      (1) 8M x 36

                            CACHE CONFIGURATION

          Size                    Bank 0                    TAG

          128KB                (4) 32K x 8         (1) 16K or (1) 32K x 8

          256KB                (4) 64K x 8         (1) 16K or (1) 32K x 8

        CACHE JUMPER CONFIGURATION

        Size                 JP3

        128KB         pins 1 & 2 closed

        256KB         pins 2 & 3 closed

                          CPU TYPE CONFIGURATION

     Type         JP5         JP6        JP7          JP8          JP9

   80486SX       Open        1 & 2       Open         Open        Open

  SL AM486DX     2 & 3       1 & 2       Open         Open        1 & 2

   80486DX       Open        1 & 2       Open         Open        Open

   CX486DX2      1 & 2       1 & 2       Open         Open        2 & 3

   AM486DX2      Open        2 & 3       Open        Closed       Open

   80486DX2      Open        1 & 2       Open         Open        Open

   CX486DX4      1 & 2       1 & 2       Open         Open        2 & 3

   AM486DX4      Open        2 & 3       Open         Open        Open

   80486DX4      Open        1 & 2       Open         Open        Open

    CX M1        2 & 3       1 & 2       Open         Open        1 & 2

     P24D        2 & 3       1 & 2       Open         Open        1 & 2

     P24T        Open        1 & 2       Open         Open        Open

  Note: Pins designated should be in the closed position.

                          CPU TYPE CONFIGURATION

       Type             RJ1                RJ2                 RJ3

     80486SX         pins 1 - 8         Installed         Not installed
                       closed

    SL AM486DX       pins 3 - 10        Installed         Not installed
                       closed

     80486DX         pins 1 - 8         Installed         Not installed
                       closed

     CX486DX2        pins 1 - 8       Not installed         Installed
                       closed

     AM486DX2        pins 1 - 8         Installed         Not installed
                       closed

     80486DX2        pins 1 - 8         Installed         Not installed
                       closed

     CX486DX4        pins 1 - 8       Not installed         Installed
                       closed

     AM486DX4        pins 1 - 8         Installed         Not installed
                       closed

     80486DX4        pins 1 - 8         Installed         Not installed
                       closed

      CX M1          pins 1 - 8         Installed         Not installed
                       closed

       P24D          pins 3 - 10        Installed         Not installed
                       closed

       P24T          pins 7 - 14        Installed         Not installed
                       closed

  Note: Pins designated should be in the closed position.

    CPU SPEED CONFIGURATION

   Speed      JP4       JP11

   25MHz      Open      Open

   33MHz     Closed    Closed

   40MHz     Closed     Open

  50iMHz      Open      Open

  66iMHz     Closed    Closed

  75iMHz      Open      Open

  80iMHz     Closed     Open

  100iMHz    Closed    Closed

  120iMHz    Closed     Open

                  CPU VOLTAGE CONFIGURATION

       Voltage               JP1                  JP2

        3.45v          pins 1 & 2 closed   pins 2 & 3 closed

        3.6v           pins 2 & 3 closed   pins 2 & 3 closed

         4v            pins 4 & 5 closed   pins 2 & 3 closed

         5v            pins 1 & 2 closed   pins 1 & 2 closed

