Premium/386-25 Processor Board                      AST Part Number 202274-001

The 386-25 Processor Board is a 25 MHz 80386 CPU/Memory adapter made
exclusively for the AST Premium/386-25 machine.  In its minimum configuration,
it comes with 2048K of RAM made up of two 32-bit 1MB modules (AST P/N
500718-001), and can be populated with a maximum of 4MBytes of memory.  The
first Megabyte is split into 640K of conventional memory and 384K of "Shadow
Ram" reserved for system use.  All subsequent memory would be addressed as
Linear Extended memory, and may be used as Expanded EMS by utilizing the
included ASTEMM.SYS memory manager.  The Processor Board also comes with 32K
of high speed ram-cache memory.  This board will support a 25MHz Intel 80387
math co-processor or a 25MHz Weitek 3167 math co-processor.

Virtually all of the configuration on the 386-25 is achieved through software
routines.  There are no switch settings on the Processor Board, and all jumpers
are for test purposes.  They should remain in their default positions at all
times.  Memory can be installed one module at a time, with bank 0 being the
first to be populated, bank 1 being the second, etc.

JUMPERS

    E1 - Leave open at all times
    E2 - Leave installed at all times


BOARD LOCATIONS

    ͻ
      +-------------------+ BANK 3          +------+                
      |                   |                 | 3167 |    +---+ 80387Ķ
      +-------------------+ BANK 2          |SOCKET|    |   |SOCKET 
      |   MEMORY  BANKS   |                 +------+    +---+       
      +-------------------+ BANK 1                                  
      |                   |                                         
      +-------------------+ BANK 0       .. E1                      
                                                                    
                                                                    
                                                  .. E2            Ķ
    ͻ            ͻ            ͼ 
           ͼ                         ͼ      
                                                                      
