SOYO COMPUTER CO., LTD.
=======================

   SY-025A2

   Processor            80486SX/80487SX/80486DX/ODP486SX/80486DX2 
   Processor Speed      25/33/50(internal)/50/66(internal)MHz     
   Chip Set             SIS                                       
   Max. Onboard DRAM    32MB                                      
   Cache                64/128/256KB                              
   BIOS                 AMI                                       
   Dimensions           220mm x 254mm                             
   I/O Options          32-bit VESA local bus slots (2)           
   NPU Options          None                                      

<gopher://bitreich.org/I/th99/m/S-T/31347-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose          | Location | Purpose           | Location |
   |------------------+----------+-------------------+----------|
   | Keylock          |   J17    | Turbo switch      |   J21    |
   |------------------+----------+-------------------+----------|
   | Speaker          |   J18    | Turbo LED         |   J22    |
   |------------------+----------+-------------------+----------|
   | Reset            |   J19    | 32-bit VESA local | S1 & S2  |
   |                  |          | bus slots (2)     |          |
   |------------------+----------+-------------------+----------|
   | External battery |   J20    |                   |          |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |              Function              | Jumper |   Position   |
   |------------------------------------+--------+--------------|
   |>> | Monitor type select color      |  JP3   |    Closed    |
   |---+--------------------------------+--------+--------------|
   |   | Monitor type select monochrome |  JP3   |     Open     |
   |---+--------------------------------+--------+--------------|
   |>> | CMOS memory normal operation   |  JP5   |  pins 1 & 2  |
   |   |                                |        |    closed    |
   |---+--------------------------------+--------+--------------|
   |   | CMOS memory clear              |  JP5   |  pins 2 & 3  |
   |   |                                |        |    closed    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     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        |
   |------------------+--------------------+--------------------|
   |       8MB        |     (4) 1M x 9     |     (4) 1M x 9     |
   |------------------+--------------------+--------------------|
   |       16MB       |     (4) 4M x 9     |        NONE        |
   |------------------+--------------------+--------------------|
   |       32MB       |     (4) 4M x 9     |     (4) 4M x 9     |
   +------------------------------------------------------------+

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

   +------------------------------------------------------------+
   |                 CACHE JUMPER CONFIGURATION                 |
   |------------------------------------------------------------|
   |       Size       |        JP6         |        JP7         |
   |------------------+--------------------+--------------------|
   |       64KB       | pins 1 & 2 closed  |        open        |
   |------------------+--------------------+--------------------|
   |      128KB       | pins 2 & 3 closed  | pins 1 & 2 closed  |
   |------------------+--------------------+--------------------|
   |      256KB       | pins 2 & 3 closed  | pins 2 & 3 closed  |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                   CPU TYPE CONFIGURATION                   |
   |------------------------------------------------------------|
   |     Type      |    JP13     |    JP14    |  JP15  |  JP16  |
   |---------------+-------------+------------+--------+--------|
   |    80486SX    |    Open     | pins 2 & 3 |  Open  |  Open  |
   |    (PQFP)     |             |   closed   |        |        |
   |---------------+-------------+------------+--------+--------|
   | 80486SX (PGA) |    Open     | pins 2 & 3 |  Open  | Closed |
   |               |             |   closed   |        |        |
   |---------------+-------------+------------+--------+--------|
   |    80487SX    | pins 2 & 3  | pins 1 & 2 | Closed | Closed |
   |               |   closed    |   closed   |        |        |
   |---------------+-------------+------------+--------+--------|
   |    80486DX    | pins 1 & 2  | pins 1 & 2 | Closed | Closed |
   |               |   closed    |   closed   |        |        |
   |---------------+-------------+------------+--------+--------|
   |   80486DX2    | pins 1 & 2  | pins 1 & 2 | Closed | Closed |
   |               |   closed    |   closed   |        |        |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  CPU SPEED CONFIGURATION                   |
   |------------------------------------------------------------|
   |  Speed   | OSC at  |  JP8 -  |  JP20   |  JP21   |  JP22   |
   |          |   Y1    |  JP11   |         |         |         |
   |----------+---------+---------+---------+---------+---------|
   |  25MHZ   |  25MHz  | pins 1  | Closed  |  Open   | Closed  |
   |          |         |   & 2   |         |         |         |
   |          |         | closed  |         |         |         |
   |----------+---------+---------+---------+---------+---------|
   |  33MHz   |  33MHz  | pins 1  |  Open   | Closed  | Closed  |
   |          |         |   & 2   |         |         |         |
   |          |         | closed  |         |         |         |
   |----------+---------+---------+---------+---------+---------|
   |  50iMHZ  |  25MHz  | pins 1  | Closed  |  Open   | Closed  |
   |          |         |   & 2   |         |         |         |
   |          |         | closed  |         |         |         |
   |----------+---------+---------+---------+---------+---------|
   |  50MHz   |  50MHz  | pins 2  |  Open   | Closed  |  Open   |
   |          |         |   & 3   |         |         |         |
   |          |         | closed  |         |         |         |
   |----------+---------+---------+---------+---------+---------|
   |  66iMHz  |  33MHz  | pins 1  |  Open   | Closed  | Closed  |
   |          |         |   & 2   |         |         |         |
   |          |         | closed  |         |         |         |
   |------------------------------------------------------------|
   | Notes:The board may come with a clock generator at Y1.     |
   |                                                            |
   | JP8 controls VESA bus slot S1's speed, JP9 Controls VESA   |
   | bus slot S1's wait states.                                 |
   |                                                            |
   | JP10 controls VESA bus slot S2's speed, JP11 Controls VESA |
   | bus slot S2's wait states.                                 |
   +------------------------------------------------------------+