X-Former                                            AST Part Number 202204-001

The Xformer (also known as "Transformer") is a 10MHz 80286 based motherboard
designed as a replacement for the IBM PC/XT system board.  By installing this
product in an existing XT, and retaining the original cabinet, power supply,
and adapters*, the machine is "transformed" into an AT compatible PC.  The
Xformer comes standard with 512K of memory, and can support 1024K with the
addition of 18 industry standard 256K DRAMS with a speed rating of 100NS. This
product will not support the installation of 64K DRAMS, and the 1024K maximum
configuration would consist of 640K Base memory and 384K of Extended memory. 
The Xformer does NOT support LIM EMS specs.

    NOTE: Any 8-bit memory enhancement products designed for use in the
          IBM XT are not supported in the Xformer.  Any memory added by way
          of the Bus must be on a 16-bit adapter.  AST also recommends the
          use of 16-bit drive controllers.  Although 8-bit drive adapters
          will operate, they will essentially "bottle-neck" the system at
          drive access, negating much of the performance increase.  Finally,
          many older boards were designed for the speed of the original IBM
          BUS speed (4.77MHz), and will malfunction at the Xformer speed of
          10MHz.


SWITCH SETTINGS

    SW1 has eight dip switches, and is used to set the amount of motherboard
    memory, the type of ROMS installed, the 80287 co-processor speed, and the
    type of video adapter installed.    * = FACTORY DEFAULT

    MEMORY            ROM TYPES            80287 SPEED            VIDEO ADAPTER

    SW1  SW2          SW3  SW4             SW5  SW6  SW7          SW8
    ---  --- -----    ---  ---  -------    ---  ---  ---  ----    ---  -----
    OFF  OFF 1024K*   ON   ON   128/128*   OFF  ON   ON   5MHZ    OFF  MONO*
    OFF  ON   512K    ON   OFF  128/256    ON   OFF  OFF  8MHZ*   ON   COLOR
    ON   ON   256K    OFF  ON   256/128
                      OFF  OFF  256/256

    NOTE: Minimum memory configuration requires that Bank One is populated
          with 256K DRAMS (512K Total).  Even if the Xformer is set to
          recognize only 256K, there must be at least 512K physically on
          the board.

JUMPER SETTINGS (* = FACTORY DEFAULT)

    E1 - FACTORY TEST - LEAVE OPEN

    E2 - MEMORY WAIT STATES
            CLOSED = ZERO WAIT STATE*
            OPEN   = ONE WAIT STATE

    E3 - FACTORY TEST - LEAVE OPEN

    E4 - BUS WAIT STATES
            CLOSED = ONE WAIT STATE*
            OPEN   = ZERO WAIT STATE

    E5 - LATCH ENABLE - LEAVE CLOSED

    E6 - FACTORY TEST - LEAVE OPEN

    NOTE: Positions E1 & E3 were removed as of board revision X5




CONNECTIONS

    There are two "J" locations of note on the Xformer.  J24 is the connector
    for the battery, and is keyed so it can not be plugged in backward.  J23
    is a ten-pin connector, and it's functions are detailed below:


                 ^      ^
                 |      |
                 |      |
              MEMORY CHIPS
         
                  2 4 6 8 10 <------------- PIN NUMBERS
                  * * * * *
SPEAKER->       * * *   * <------- PINS
CONNECT->       1 3 5 7 9
         
                            FRONT EDGE OF XFORMER

    The J23 connection is for cabinets that have a front panel with
    functions such as keyboard lock, reset, and system speed LED's.
    The pin's duties are:

        1 - VCC +5V         2 - GROUND
        3 - GROUND          4 - HIGH SPEED INDICATOR (LED)
        5 - N/A             6 - LOW SPEED INDICATOR (LED)
        7 - CLIPPED         8 - HARDWARE RESET
        9 - KEYBOARD LOCK  10 - N/A

    The LED's connect to the voltage (pin 1).  On the Xformer, high
    speed is 10MHz and low speed is 6MHz.  A power-on indicator LED
    should connect pin 1 to one of the grounds.  Both the reset and
    the keyboard lock connect to a ground.


SWITCH, JUMPER, AND CONNECTION LOCATIONS

    ͻ
     <--SPEAKER CONNECTOR                 
     *<--J23 PANEL CONNECTOR                                   
                                           
                                                               
                                 
                                                               
                                 
                          *E4                                  
                                 
      SW1              *E3                                     
     +---+                       
     +---+                                                     
    ͻ                                
                                                               
                     *E2                   
                                                  *E6          
                 *E1                                           
                                                        *J24   
                             *E5                               
           ͼ
