
I-BUS

ORCA (REV. B)

Processor     CX486/AM486/80486SX/SL80486/80486DX/80486DX4/P24D/P24T
Processor     25/33/40/50(internal)/50/66(internal)100(internal)MHz
Speed
Chip Set      OPTI
Video Chip    Cirrus Logic
Set
Maximum       128MB
Onboard
Memory
Maximum Video 2MB
Memory
Cache         64/128/256/512KB
BIOS          Unidentified
Dimensions    Unidentified
I/O Options   Floppy drive interface, IDE interface, parallel port, PS/2
              mouse port, serial ports (2), VGA port
NPU Options   None

[Image]

                                CONNECTIONS

  Purpose                 Location     Purpose                 Location

  IDE interface              J2        Auxiliary keyboard         J14
                                       connector

  Floppy drive               J3        PS/2 mouse port            J21
  interface

  Parallel port              J4        Reset switch               J22

  Serial port 1              J5        Speaker                    J25

  Serial port 2              J6        Chassis fan power          J26

  IDE interface LED          J9        VGA port                   J33

                        USER CONFIGURABLE SETTINGS

              Function                    Label            Position

      IDE IRQ14 enabled                    J1               Closed

      IDE IRQ14 disabled                   J1                Open

      IDE read prefetch enabled            J8         Pins 1 & 2 closed

      IDE read prefetch disabled           J8         Pins 2 & 3 closed

      IDE type select primary              J11        Pins 1 & 3 closed

      IDE type select secondary            J11        Pins 3 & 5 closed

      IDE interface enabled                J11        Pins 2 & 4 closed

      IDE interface disabled               J11        Pins 4 & 6 closed

     Factory configured - do not          J12               Open
      alter

      Floppy drive select 1.44MB           J13        Pins 1 & 2 closed

      Floppy drive select 2.88MB           J13         Pins 3 & 4, 5 & 6
                                                            closed

     CMOS memory normal operation         J17        Pins 2 & 3 closed

      CMOS memory clear                    J17        Pins 1 & 2 closed

      PS/2 mouse IRQ12 enabled             J18              Closed

      PS/2 mouse IRQ12 disabled            J18               Open

      Password enabled                     J19              Closed

      Password disabled                    J19               Open

      Video IRQ9 enabled                   J31              Closed

      Video IRQ9 disabled                  J31               Open

     Factory configured - do not          J38           Unidentified
      alter

                            DRAM CONFIGURATION

      Size          Bank 0        Bank 1         Bank 2         Bank 3

      4MB         (1) 1M x 36      None           None           None

      8MB         (1) 2M x 36      None           None           None

      8MB         (1) 1M x 36   (1) 1M x 36       None           None

      16MB        (1) 4M x 36      None           None           None

      16MB        (1) 2M x 36   (1) 2M x 36       None           None

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

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

      32MB        (1) 8M x 36      None           None           None

      32MB        (1) 4M x 36   (1) 4M x 36       None           None

      32MB        (1) 2M x 36   (1) 2M x 36    (1) 2M x 36   (1) 2M x 36

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

      48MB        (1) 4M x 36   (1) 4M x 36    (1) 2M x 36   (1) 2M x 36

      64MB        (1) 8M x 36   (1) 8M x 36       None           None

      64MB        (1) 4M x 36   (1) 4M x 36    (1) 4M x 36   (1) 4M x 36

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

      80MB        (1) 8M x 36   (1) 8M x 36    (1) 2M x 36   (1) 2M x 36

      96MB        (1) 8M x 36   (1) 8M x 36    (1) 4M x 36   (1) 4M x 36

     128MB         (1) 16M x     (1) 16M x        None           None
                      36            36

     128MB        (1) 8M x 36   (1) 8M x 36    (1) 8M x 36   (1) 8M x 36

                            CACHE CONFIGURATION

  Note: Board accepts 64KB/128KB/256KB/512KB cache. The location of banks
  0 & 1 is unidentified.

                      CACHE JUMPER CONFIGURATION

               Size                               J15

               64KB                               Open

               128KB                       Pins 5 & 6 closed

               256KB                    Pins 3 & 4, 5 & 6 closed

               512KB                Pins 1 & 2, 3 & 4, 5 & 6 closed

         CACHE BANK CONFIGURATION

       Setting               J16

     Single bank      Pins 1 & 2 closed

     Dual banks       Pins 2 & 3 closed

                        VIDEO MEMORY CONFIGURATION

  Note: Board accepts up to 2MB of video memory. The location and chip
  sizes are unidentified.

                            CPU SPEED SELECTION

          Speed                     J7                      J28

          25MHz              Pins 1 & 3, 2 & 4       Pins 5 & 6 closed
                                  closed

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

          40MHz              Pins 2 & 4, 3 & 5        Pins 3 & 4, 5 & 6
                                  closed                   closed

         50iMHz              Pins 1 & 3, 2 & 4       Pins 5 & 6 closed
                                  closed

          50MHz              Pins 3 & 5, 4 & 6     Pins 1 & 2, 3 & 4, 5 &
                                  closed                  6 closed

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

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

                            CPU TYPE SELECTION

         Type                     J29                       J37

         Cyrix             Pins 2 & 3 closed         Pins 1 & 2, 3 & 4
                                                          closed

          AMD              Pins 1 & 2 closed               Open

         Intel             Pins 1 & 2 closed               Open

                   CPU TYPE SELECTION

            Type                        J36

          Intel SX               Pins 2 & 3 closed

          Intel DX           Pins 1 & 2, 3 & 4 closed

                   CPU TYPE SELECTION

            Type                        J24

          SL80486            Pins 1 & 2, 3 & 4 closed

         P24T burst              Pins 5 & 6 closed

          P24T WB                Pins 7 & 8 closed

          P24T WT                      Open

            CPU TYPE SELECTION

        Type                 J34

        Cyrix         Pins 4 & 6 closed

       SL80486        Pins 2 & 4 closed

       P24D WB        Pins 3 & 5 closed

       P24D WT        Pins 1 & 3 closed

              CPU TYPE SELECTION

         Type                   J35

     All CPU types       Pins 1 & 3 closed

       P24T only         Pins 3 & 5 closed

  Bit 0 to stop clock    Pins 2 & 4 closed

  Bit 1 to stop clock    Pins 4 & 6 closed

         CPU MULTIPLIER SELECTION

     Multiplier              J23

      Cyrix CPU       Pins 3 & 4 closed

         2x           Pins 3 & 5 closed

        2.5x          Pins 1 & 3 closed

         3x                  Open

         CPU FREQUENCY SELECTION

        Speed                J27

        8MHz          Pins 1 & 2 closed

     16MHz (DX4)      Pins 2 & 3 closed

                 DMA CHANNEL SELECTION

          Channel                       J32

             1               Pins 3 & 4, 5 & 6 closed

             3               Pins 1 & 2, 7 & 8 closed

                   IDE MODE SELECTION

           Speed                        J10

           180ns             Pins 1 & 3, 2 & 4 closed

           240ns             Pins 3 & 5, 2 & 4 closed

           383ns             Pins 1 & 3, 4 & 6 closed

           480ns             Pins 3 & 5, 4 & 6 closed

                   ON BOARD VIDEO SELECTION

       Setting               J30                  J39

       Enabled         Pins 2 & 3 closed         Closed

      Disabled         Pins 1 & 2 closed          Open

