
EVEREX SYSTEMS, INC.

STEP 486SX20 (EV-18116)

Processor           80486SX/80487SX/80486DX
Processor Speed     20/25MHz
Chip Set            C & T
Max. onboard DRAM   32MB
Cache               128/256KB
BIOS                AMI
Dimensions          330mm x 218mm
I/O Options         32-bit external memory card, floppy drive interface,
                    IDE interface, parallel port, serial ports (2)
NPU Options         4167

[Image]

                                CONNECTIONS

  Purpose                  Location    Purpose                  Location

  Parallel port              CN1       Floppy drive               CN5
                                       interface

  Serial port (COM1)         CN2       32-bit external             S1
                                       memory card

  Serial port (COM2)         CN3       Instep socket              U19

  IDE interface              CN4

                      CACHE CONFIGURATION

      Size       Max Cachable       Bank 0          Bank 1

     128KB           16MB         (4) 32K x 8        NONE

     256KB           32MB         (8) 32K x 8    Banks 0 & 1

        CACHE JUMPER CONFIGURATION

        Size                  P1

        128KB         pins 2 & 3 closed

        256KB         pins 2 & 3 closed

                        SERIAL PORT 1 CONFIGURATION

      COM1         J15/1 & 2      J15/3 & 4     J15/5 & 6      J15/7 & 8

         IRQ3         Open         Closed          Open          Open

        IRQ4         Open          Open          Closed         Open

         IRQ5         Open          Open           Open         Closed

         IRQ9        Closed         Open           Open          Open

                         SERIAL PORT CONFIGURATION

      COM2         J15/9 & 10    J15/11 & 12    J15/13 & 14   J15/15 & 16

        IRQ3         Open         Closed          Open          Open

         IRQ4         Open          Open          Closed         Open

         IRQ5         Open          Open           Open         Closed

         IRQ9        Closed         Open           Open          Open

                        PARALLEL PORT CONFIGURATION

       LPT 2         J12/pins 1 & 2     J12/pins 3 & 4    J12/pins 5 & 6

          IRQ5            Open              Closed             Open

         IRQ7            Open               Open             Closed

          IRQ9           Closed              Open              Open

                          CPU TYPE CONFIGURATION

     Type            JP1            JP2            JP3           JP4

    80486SX       pins 1 & 2        Open          Open           Open
                    closed

    80487SX       pins 2 & 3       Closed        Closed          Open
                    closed

    80486DX       pins 2 & 3       Closed         Open          Closed
                    closed

[Image]

                            DRAM CONFIGURATION

     Size         Bank 0         Bank 1         Bank 2         Bank 3

     1MB        (4) 256K x 9      NONE           NONE           NONE

     2MB        (4) 256K x 9   (4) 256K x 9      NONE           NONE

     3MB        (4) 256K x 9   (4) 256K x 9   (4) 256K x 9      NONE

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

     4MB        (4) 1M x 9        NONE           NONE           NONE

     5MB        (4) 1M x 9     (4) 256K x 9      NONE           NONE

     6MB        (4) 1M x 9     (4) 256K x 9   (4) 256K x 9      NONE

     7MB        (4) 1M x 9     (4) 256K x 9   (4) 256K x 9  (4) 256K x 9

     8MB        (4) 1M x 9     (4) 1M x 9        NONE           NONE

     9MB        (4) 1M x 9     (4) 1M x 9     (4) 256K x 9      NONE

     10MB       (4) 1M x 9     (4) 1M x 9     (4) 256K x 9  (4) 256K x 9

     12MB       (4) 1M x 9     (4) 1M x 9     (4) 1M x 9        NONE

     13MB       (4) 1M x 9     (4) 1M x 9     (4) 1M x 9    (4) 256K x 9

     16MB       (4) 1M x 9     (4) 1M x 9     (4) 1M x 9     (4) 1M x 9

     16MB       (4) 4M x 9        NONE           NONE           NONE

     17MB       (4) 4M x 9     (4) 256K x 9      NONE           NONE

     18MB       (4) 4M x 9     (4) 256K x 9   (4) 256K x 9      NONE

     20MB       (4) 4M x 9     (4) 1M x 9        NONE           NONE

     21MB       (4) 4M x 9     (4) 1M x 9     (4) 256K x 9      NONE

     22MB       (4) 4M x 9     (4) 1M x 9     (4) 256K x 9  (4) 256K x 9

     24MB       (4) 4M x 9     (4) 1M x 9     (4) 1M x 9        NONE

     25MB       (4) 4M x 9     (4) 1M x 9     (4) 1M x 9    (4) 256K x 9

     28MB       (4) 4M x 9     (4) 1M x 9     (4) 1M x 9     (4) 1M x 9

                         DRAM CONFIGURATION CON'T

     32MB        (4) 4M x 9    (4) 4M x 9        NONE           NONE

     33MB        (4) 4M x 9    (4) 4M x 9    (4) 256K x 9       NONE

     34MB        (4) 4M x 9    (4) 4M x 9    (4) 256K x 9   (4) 256K x 9

     36MB        (4) 4M x 9    (4) 4M x 9     (4) 1M x 9        NONE

     37MB        (4) 4M x 9    (4) 4M x 9     (4) 1M x 9    (4) 256K x 9

     40MB        (4) 4M x 9    (4) 1M x 9     (4) 1M x 9     (4) 4M x 9

     48MB        (4) 4M x 9    (4) 4M x 9     (4) 4M x 9        NONE

     49MB        (4) 4M x 9    (4) 4M x 9     (4) 4M x 9    (4) 256K x 9

     52MB        (4) 4M x 9    (4) 4M x 9     (4) 4M x 9     (4) 1M x 9

     64MB        (4) 4M x 9    (4) 4M x 9     (4) 4M x 9     (4) 4M x 9

