
ACER, INC.

ISA486GXi MODEL I433A

Processor         80486SX/80487SX/80486DX/ODP486SX/80486DX2
Processor Speed   20/25/33/50(internal)/66(internal)
Chip Set          ALI
Max. Onboard DRAM 32MB
SRAM Cache        64/256KB
BIOS              Acer
Dimensions        220mm x 240mm
I/O Options       None
NPU Options       None

[Image]

                                CONNECTIONS

  Purpose                 Location      Purpose               Location

  External battery          JP5         Turbo LED            JP16/12 & 13

  Power LED & keylock    JP16/1 - 5     Turbo switch         JP16/15 - 17

  Speaker               JP16/7 - 10     Reset switch         JP16/19 & 20

                            SRAM CONFIGURATION

   Size      Cache       TAG      (U36)       JP10      JP11       JP12

   64KB     (8) 8K x    (1) 8K   (1) 16K      open      pins 2   pins 1 &
               8         x 8       x 4                   & 3        2

   64KB     (8) 8K x    (1) 8K    NONE        open      pins 1   pins 2 &
               8         x 8                             & 2        3

   256KB     (8) 32K   (1) 32K   (1) 16K     closed     pins 2   pins 1 &
              x 8        x 8       x 4                   & 3        2

   256KB     (8) 32K   (1) 32K    NONE       closed     pins 1   pins 2 &
              x 8        x 8                             & 2        3

  Note:Pins designated should be in the closed position.

  JP10 is closed by shorting pins 1 & 2, 3 & 4, and 5 & 6.

                        USER CONFIGURABLE SETTINGS

                 Function                     Jumper         Position

     CMOS memory normal operation             JP6             open

      CMOS memory clear                        JP6            closed

      System automatically detects CPU         JP7            closed
      type installed

      System detects only 486SX/DX CPUs        JP7             open

     Factory configured - do not alter        JP8           pins 1 & 2
                                                              closed

     Factory configured - do not alter        JP13          pins 1 & 2
                                                              closed

     Factory configured - do not alter        JP17            open

              DRAM CONFIGURATION

      Size          Bank 0          Bank 1

      1MB         (4) 256K x 9       NONE

      2MB         (4) 256K x 9   (4) 256K x 9

      2MB         (4) 512K x 9       NONE

      4MB         (4) 512K x 9   (4) 512K x 9

      4MB         (4) 1M x 9         NONE

      5MB         (4) 1M x 9     (4) 256K x 9

      6MB         (4) 512K x 9    (4) 1M x 9

      8MB         (4) 1M x 9      (4) 1M x 9

      16MB        (4) 4M x 9         NONE

      17MB        (4) 256K x 9    (4) 4M x 9

      18MB        (4) 512K x 9    (4) 4M x 9

      20MB        (4) 1M x 9      (4) 4M x 9

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

           CPU SPEED CONFIGURATION FOR CH9001 SYSTEM CLOCK CHIP

       CPU Speed                   JP1                      JP9

         20MHz              pins 1 & 2 closed        pins 2 & 3 closed

         25MHz                    open               pins 2 & 3 closed

         33MHz              pins 3 & 4 closed        pins 2 & 3 closed

         40MHz             pins 1 & 2 and 5 & 6      pins 1 & 2 closed
                                 closed

         50MHz              pins 5 & 6 closed        pins 1 & 2 closed

          CPU SPEED CONFIGURATION FOR IMISC425 SYSTEM CLOCK CHIP

       CPU Speed                  JP1                       JP9

         20MHz            pins 1 & 2 and 3 & 4       pins 2 & 3 closed
                                closed

         25MHz             pins 3 & 4 closed         pins 2 & 3 closed

         33MHz             pins 1 & 2 closed         pins 2 & 3 closed

         40MHz           pins 1 & 2, 3 & 4, and      pins 1 & 2 closed
                             5 & 6 closed

         50MHz             pins 5 & 6 closed         pins 1 & 2 closed

