INTEL CORPORATION
=================

   R486SX254F/R486SX33F/R486DX334F/R486DX2664F

   Processor    80486SX/80487SX/80486DX/ODP486SX/80486DX2/Pentium 
                Overdrive                                         
   Processor    25/33/50(internal)/66(internal)MHz                
   Speed        
   Chip Set     VLSI                                              
   Max. Onboard 32MB                                              
   DRAM         
   Cache        64/128/256KB                                      
   BIOS         Phoenix                                           
   Dimensions   330mm x 218mm                                     
   I/O Options  32-bit proprietary riser card slot, floppy drive  
                interface,IDE interface, parallel port, PS/2      
                mouse port,serial ports (2), VGA feature          
                connector, VGA port                               
   NPU Options  None                                              

<gopher://bitreich.org/I/th99/m/I-L/31982-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose             | Location | Purpose        | Location |
   |---------------------+----------+----------------+----------|
   | VGA port            |    J1    | Floppy drive   |   J15    |
   |                     |          | interface      |          |
   |---------------------+----------+----------------+----------|
   | Parallel port       |    J2    | +5V auxiliary  |   J26    |
   |                     |          | fan power      |          |
   |---------------------+----------+----------------+----------|
   | Serial port 2       |    J3    | IDE interface  |   J29    |
   |                     |          | LED            |          |
   |---------------------+----------+----------------+----------|
   | Serial port 1       |    J4    | Power LED &    |   J30    |
   |                     |          | Keylock        |          |
   |---------------------+----------+----------------+----------|
   | PS/2 mouse port     |    J5    | Reset switch   |   J31    |
   |---------------------+----------+----------------+----------|
   | 32 Bit proprietary  |    J7    | +12V auxiliary |   J32    |
   | riser card          |          | fan power      |          |
   |---------------------+----------+----------------+----------|
   | VGA feature         |   J10    | External       |   J33    |
   | connector           |          | speaker        |          |
   |---------------------+----------+----------------+----------|
   | IDE interface       |   J14    |                |          |
   |------------------------------------------------------------|
   | Note:To connect an external speaker, remove the jumper     |
   | from pins 3 & 4 and connect external speaker between pins  |
   | 1 & 4.                                                     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |               Function               | Jumper |  Position  |
   |--------------------------------------+--------+------------|
   |>> | FLASH BIOS programming enabled   |  J12   | pins 1 & 2 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | FLASH BIOS programming disabled  |  J12   | pins 2 & 3 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |>> | Normal FLASH operation           |  J13   | pins 1 & 2 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | Invoke boot block recovery       |  J13   | pins 2 & 3 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |>> | Enable onboard video             |  J16   | pins 1 & 2 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | Disable onboard video            |  J16   | pins 2 & 3 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |>> | Disable floppy drive write       |  J17   | pins 2 & 3 |
   |   | protect                          |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | Enable floppy drive write        |  J17   | pins 1 & 2 |
   |   | protect                          |        |   closed   |
   |---+----------------------------------+--------+------------|
   |>> | Enable password                  |  J20   | pins 2 & 3 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | Disable password                 |  J20   | pins 1 & 2 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |>> | Enable user to enter Setup       |  J21   | pins 1 & 2 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | Prevent user to enter Setup      |  J21   | pins 2 & 3 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |>> | CMOS normal operation            |  J28   |   Closed   |
   |---+----------------------------------+--------+------------|
   |   | CMOS clear upon power-up         |  J28   |    Open    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   |       Size       |       Bank 0       |       Bank 1       |
   |------------------+--------------------+--------------------|
   |       2MB        |   (1) 512K x 36    |        NONE        |
   |------------------+--------------------+--------------------|
   |       4MB        |   (1) 512K x 36    |   (1) 512K x 36    |
   |------------------+--------------------+--------------------|
   |       4MB        |    (1) 1M x 36     |        NONE        |
   |------------------+--------------------+--------------------|
   |       6MB        |   (1) 512K x 36    |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       6MB        |    (1) 1M x 36     |   (1) 512K x 36    |
   |------------------+--------------------+--------------------|
   |       8MB        |    (1) 1M x 36     |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       8MB        |    (1) 2M x 36     |        NONE        |
   |------------------+--------------------+--------------------|
   |       10MB       |    (1) 2M x 36     |   (1) 512K x 36    |
   |------------------+--------------------+--------------------|
   |       10MB       |   (1) 512K x 36    |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       12MB       |    (1) 2M x 36     |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       16MB       |    (1) 1M x 36     |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       16MB       |    (1) 2M x 36     |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       16MB       |    (1) 4M x 36     |        NONE        |
   |------------------+--------------------+--------------------|
   |       18MB       |   (1) 512K x 36    |    (1) 4M x 36     |
   |------------------+--------------------+--------------------|
   |       18MB       |    (1) 4M x 36     |   (1) 512K x 36    |
   |------------------+--------------------+--------------------|
   |       20MB       |    (1) 1M x 36     |    (1) 4M x 36     |
   |------------------+--------------------+--------------------|
   |       20MB       |    (1) 4M x 36     |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       24MB       |    (1) 2M x 36     |    (1) 4M x 36     |
   |------------------+--------------------+--------------------|
   |       24MB       |    (1) 4M x 36     |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       32MB       |    (1) 4M x 36     |    (1) 4M x 36     |
   +------------------------------------------------------------+

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

   +------------------------------------------------------------+
   |                 CACHE JUMPER CONFIGURATION                 |
   |------------------------------------------------------------|
   |           Size           |               J11               |
   |--------------------------+---------------------------------|
   |           64KB           |              Open               |
   |--------------------------+---------------------------------|
   |          128KB           |    pins 1 & 2, 5 & 6 closed     |
   |--------------------------+---------------------------------|
   |          256KB           | pins 1 & 2, 3 & 4, 7 & 8 closed |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                   CPU TYPE CONFIGURATION                   |
   |------------------------------------------------------------|
   | CPU Type |     J22      |    J23     |   J24    |   J25    |
   |----------+--------------+------------+----------+----------|
   | 80486SX  |  pins 1 & 2  | pins 2 & 3 | pins 2 & | pins 2 & |
   |          |    closed    |   closed   | 3 closed | 3 closed |
   |----------+--------------+------------+----------+----------|
   | 80487SX  |  pins 2 & 3  | pins 1 & 2 | pins 2 & | pins 1 & |
   |          |    closed    |   closed   | 3 closed | 2 closed |
   |----------+--------------+------------+----------+----------|
   | 80486DX  |  pins 2 & 3  | pins 1 & 2 | pins 1 & | pins 2 & |
   |          |    closed    |   closed   | 2 closed | 3 closed |
   |----------+--------------+------------+----------+----------|
   | 80486DX2 |  pins 2 & 3  | pins 1 & 2 | pins 1 & | pins 2 & |
   |          |    closed    |   closed   | 2 closed | 3 closed |
   |----------+--------------+------------+----------+----------|
   | ODP486SX |  pins 2 & 3  | pins 1 & 2 | pins 2 & | pins 1 & |
   |          |    closed    |   closed   | 3 closed | 2 closed |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  CPU SPEED CONFIGURATION                   |
   |------------------------------------------------------------|
   |    CPU Speed     |        J18         |        J19         |
   |------------------+--------------------+--------------------|
   |      25MHz       | pins 1 & 2 closed  | pins 1 & 2 closed  |
   |------------------+--------------------+--------------------|
   |      33MHz       | pins 1 & 2 closed  | pins 2 & 3 closed  |
   |------------------+--------------------+--------------------|
   |      50iMHz      | pins 1 & 2 closed  | pins 1 & 2 closed  |
   |------------------+--------------------+--------------------|
   |      66iMHz      | pins 1 & 2 closed  | pins 2 & 3 closed  |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     VRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   |       Size       |       Bank 0       |       Bank 1       |
   |------------------+--------------------+--------------------|
   |       512K       |    (4) 256 x 4     |        NONE        |
   |------------------+--------------------+--------------------|
   |       1MB        |    (4) 256 x 4     |    (4) 256 x 4     |
   +------------------------------------------------------------+