IBM CORPORATION

PERSONAL SYSTEM/2 HMM

Processor   80486SX/80486DX/80486DX2/80486DX4/P24T
Processor   25/33/50(internal/66(internal)/75(internal)/100(internal)/MHz
Speed
Chip Set    Unidentified
Video Chip  None
Set
Maximum     Unidentified
Onboard
Memory
Maximum     None
Video
Memory
Cache       128/256KB
BIOS        Unidentified
Dimensions  254mm x 218mm
I/O Options 32-bit PCI slots (3), floppy drive interface, IDE interfaces
            (2), parallel port, PS/2 mouse port, serial ports (2)
NPU Options None

[Image]

                                CONNECTIONS

  Purpose                  Location    Purpose                  Location

  PS/2 mouse port             J2       IDE interface 1            J21

  Speaker                     J5       IDE interface 2            J22

  Parallel port               J8       32-bit PCI slots         PC1 – PC3

  Floppy drive interface      J9       Power LED                  W12

  Serial port 2              J10       IDE interface LED          W39
                                       (PCI)

  Serial port 1              J11       IDE interface LED          W46
                                       (ISA)

                        USER CONFIGURABLE SETTINGS

                Function                     Label           Position

  »   Secondary cache write select             W1           Pins 2 & 3
      write back                                              closed

      Secondary cache write select             W1           Pins 1 & 2
      write through                                           closed

  »   Internal cache write select write        W4              Open
      through

      Internal cache write select write        W4             Closed
      back

  »   Flash BIOS normal operation              W6           Pins 2 & 3
                                                              closed

      Flash BIOS recovery mode                 W6           Pins 1 & 2
                                                              closed

  »   Factory configured - do not alter        W8             Closed

  »   PS/2 mouse installed                    W10             Closed

      PS/2 mouse not installed                W10              Open

      Parity generation select DPU            W17           Pins 1 & 2
                                                              closed

      Parity generation select CPU            W17           Pins 2 & 3
                                                              closed

  »   DPU does not force parity               W18           Pins 2 & 3
                                                              closed

      DPU forces parity                       W18           Pins 1 & 2
                                                              closed

  »   Factory configured - do not alter       W19             Closed

  »   Cache installed                         W21              Open

      Cache not installed                     W21             Closed

                      DRAM CONFIGURATION

  Note: The maximum size and configuration is unidentified.

                   CACHE CONFIGURATION

  Note: The location and configuration is unidentified.

         CACHE JUMPER SELECTION

   Size       W5       W22       W23

  128KB      Open    Closed     Open

  256KB     Closed    Open     Closed

                            CACHE TAG SELECTION

           Size                      W24                     W26

             7-bit                   Open                  Closed

             8-bit                  Closed                 Closed

  »          9-bit                  Closed                  Open

      CPU SPEED SELECTION

   Speed      W16        W20

   25MHz      Open     Closed

   33MHz     Closed     Open

  50iMHz      Open     Closed

  66iMHz     Closed     Open

  75iMHz      Open     Closed

  100iMHz    Closed     Open

                            CPU TYPE SELECTION

           Type                      W2                      W3

         80486SX             Pins 2 & 3 closed             Closed

         80486DX              Pins 1 & 2, 3 & 4            Closed
                                   closed

         80486DX2             Pins 1 & 2, 3 & 4            Closed
                                   closed

         80486DX4             Pins 1 & 2, 3 & 4            Closed
                                   closed

           P24T               Pins 1 & 2, 3 & 4             Open
                                   closed

         CPU MULTIPLIER SELECTION

     Multiplier              W33

         1x           Pins 1 & 2 closed

         2x           Pins 2 & 3 closed

         3x                  Open

                           DMA CHANNEL SELECTION

                 Channel                                W43

  »       ISA IDE used P10 transfer                    Open

                      6                          Pins 1 & 2 closed

                      7                          Pins 2 & 3 closed

          ISA IDE IRQ SELECTION

         IRQ                 W42

        IRQ14         Pins 1 & 2 closed

        IRQ15         Pins 2 & 3 closed

                           PCI IDE IRQ SELECTION

            IRQ                      W35                     W38

  »          IRQ14                  Closed                  Open

             IRQ15                   Open                  Closed

       PCI INTERRUPT SELECTION

      Setting             W37

  INTR_A enabled         Closed

  INTR_A disabled         Open

  PCI COMPLIANT IRQ SELECTION

      IRQ             J101

      IRQ1           Pin 2

      IRQ3           Pin 3

      IRQ4           Pin 4

      IRQ5           Pin 5

      IRQ6           Pin 6

      IRQ7           Pin 7

      IRQ8           Pin 8

      IRQ9           Pin 9

     IRQ10           Pin 10

     IRQ11           Pin 11

     IRQ12           Pin 12

     IRQ14           Pin 13

     IRQ15           Pin 14