J-MARK COMPUTER CORPORATION
===========================

   486SX/DX VERSION II

   Processor         80486SX/80487SX/80486DX/80486DX2             
   Processor Speed   16/20/25/33/50(internal)/50/66(internal) MHz 
   Chip Set          OPTI                                         
   Max. onboard DRAM 32MB                                         
   Cache             64/128/256KB                                 
   BIOS              AMI                                          
   Dimensions        240mm x 220mm                                
   I/O Options       None                                         
   NPU Options       None                                         

<gopher://bitreich.org/I/th99/m/I-L/31456-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose          | Location | Purpose           | Location |
   |------------------+----------+-------------------+----------|
   | External battery |    J1    | Speaker           |   J17    |
   |------------------+----------+-------------------+----------|
   | Turbo switch     |   JP9    | Power LED &       |   J18    |
   |                  |          | keylock           |          |
   |------------------+----------+-------------------+----------|
   | Turbo LED        |   JP10   | Reset switch      |   SW1    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |              Function              | Jumper |   Position   |
   |------------------------------------+--------+--------------|
   |>> | CMOS memory normal operation   |  JP1   |  pins 1 & 2  |
   |   |                                |        |    closed    |
   |---+--------------------------------+--------+--------------|
   |   | CMOS memory clear              |  JP1   |  pins 2 & 3  |
   |   |                                |        |    closed    |
   |---+--------------------------------+--------+--------------|
   |>> | Monitor type select color      |  JP2   |    Closed    |
   |---+--------------------------------+--------+--------------|
   |   | Monitor type select monochrome |  JP2   |     Open     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   |       Size       |       Bank 0       |       Bank 1       |
   |------------------+--------------------+--------------------|
   |       1MB        |    (4) 256K x 9    |        NONE        |
   |------------------+--------------------+--------------------|
   |       2MB        |    (4) 256K x 9    |    (4) 256K x 9    |
   |------------------+--------------------+--------------------|
   |       4MB        |     (4) 1M x 9     |        NONE        |
   |------------------+--------------------+--------------------|
   |       5MB        |    (4) 256K x 9    |     (4) 1M x 9     |
   |------------------+--------------------+--------------------|
   |       8MB        |     (4) 1M x 9     |     (4) 1M x 9     |
   |------------------+--------------------+--------------------|
   |       16MB       |     (4) 4M x 9     |        NONE        |
   |------------------+--------------------+--------------------|
   |       20MB       |     (4) 1M x 9     |     (4) 4M x 9     |
   |------------------+--------------------+--------------------|
   |       32MB       |     (4) 4M x 9     |     (4) 4M x 9     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                    CACHE CONFIGURATION                     |
   |------------------------------------------------------------|
   | Size  |   Bank 0    |   Bank 1   | TAG (U39)  | TAG (U40)  |
   |-------+-------------+------------+------------+------------|
   | 64KB  | (4) 8K x 8  |    NONE    | (1) 8K x 8 |    NONE    |
   |-------+-------------+------------+------------+------------|
   | 128KB | (4) 32K x 8 |    NONE    | (1) 8K x 8 |    NONE    |
   |-------+-------------+------------+------------+------------|
   | 256KB | (4) 32K x 8 | (4) 32K x  | (1) 8K x 8 | (1) 8K x 8 |
   |       |             |     8      |            |            |
   |-------+-------------+------------+------------+------------|
   | 256KB | (4) 32K x 8 | (4) 32K x  | (1) 32K x  |    NONE    |
   |       |             |     8      |     8      |            |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 CACHE JUMPER CONFIGURATION                 |
   |------------------------------------------------------------|
   | Size  |  JP5   |  JP6   |  JP7   |  JP8  |  JP15  |  JP16  |
   |-------+--------+--------+--------+-------+--------+--------|
   | 64KB  |  Open  |  Open  |  Open  | pins  |  Open  |  Open  |
   |       |        |        |        | 2 & 3 |        |        |
   |-------+--------+--------+--------+-------+--------+--------|
   | 128KB | Closed |  Open  | Closed | pins  |  Open  | Closed |
   |       |        |        |        | 1 & 2 |        |        |
   |-------+--------+--------+--------+-------+--------+--------|
   | 256KB | Closed | Closed | Closed | pins  | closed | closed |
   |       |        |        |        | 2 & 3 |        |        |
   |------------------------------------------------------------|
   | Note:Pins designated should be in the closed postion.      |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                   CPU TYPE CONFIGURATION                   |
   |------------------------------------------------------------|
   |   CPU type   |  JP17  |     JP18     |  JP19  |    JP20    |
   |--------------+--------+--------------+--------+------------|
   | 80486SX PQFP |  Open  |     Open     | Closed | pins 2 & 3 |
   |              |        |              |        |   closed   |
   |--------------+--------+--------------+--------+------------|
   | 80486SX PGA  | Closed |     Open     | Closed | pins 2 & 3 |
   |              |        |              |        |   closed   |
   |--------------+--------+--------------+--------+------------|
   |   80487SX    | Closed |  pins 2 & 3  | Closed | pins 1 & 2 |
   |              |        |    closed    |        |   closed   |
   |--------------+--------+--------------+--------+------------|
   | 80486DX/DX2  | Closed |  pins 1 & 2  | Closed | pins 1 & 2 |
   |              |        |    closed    |        |   closed   |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  CPU SPEED CONFIGURATION                   |
   |------------------------------------------------------------|
   |   Speed    |   JP11    |   JP12    |   JP13    |   JP14    |
   |------------+-----------+-----------+-----------+-----------|
   |   16MHz    |  Closed   |  Closed   |  Closed   |  Closed   |
   |------------+-----------+-----------+-----------+-----------|
   |   20MHz    |   Open    |  Closed   |  Closed   |   Open    |
   |------------+-----------+-----------+-----------+-----------|
   |   25MHz    |   Open    |  Closed   |   Open    |  Closed   |
   |------------+-----------+-----------+-----------+-----------|
   |   33MHz    |   Open    |   Open    |  Closed   |   Open    |
   |------------+-----------+-----------+-----------+-----------|
   |  50i MHz   |   Open    |  Closed   |   Open    |  Closed   |
   |------------+-----------+-----------+-----------+-----------|
   |   50MHz    |   Open    |   Open    |  Closed   |   Open    |
   |------------+-----------+-----------+-----------+-----------|
   |  66i MHz   |   Open    |   Open    |  Closed   |   Open    |
   +------------------------------------------------------------+