AMI TECH TIP


TECH TIP NO.       16.005

DATE:              August 19, 1991
BOARD TYPE:        Enterprise II, Series-16
BOARD REVISION:    D, D1, or E
BOARD FREQUENCY:   25MHz or 33MHz
ORIGINATOR:        Rex Wade
RELEASED BY:       Documentation Control


PROBLEM:           In order to have a system approved as a Banyan VINES server,
		   a Banyan ICA card must be installed.  This card has 128KB 
		   (20000 hex bytes) of dual ported memory that must be located
		   on a 128K (20000 hex) boundary.  Addresses A0000 to BFFFF 
		   (hex) are reserved for video memory.  Addresses C0000 to
                   DFFFF (hex) are reserved for video, disk, and other 
		   peripheral BIOS.  Addresses E0000 to FFFFF (hex) are used by
		   the system BIOS.  This means that some other portion of 
		   memory must be used.  However if 16MB of DRAM is installed,
		   there are no other locations below the 16MB boundary that 
		   are available.

SOLUTION:          By changing the PAL at location U19, the addresses between 
		   80000 to 9FFFF (hex) can be disabled to the DRAM allowing 
		   this address range to be used by the Banyan ICA card memory.
		   This will limit the base memory (below 1MB) to 512KB instead
		   of 640KB and reduce the overall memory by 128KB.  The new
                   PAL number is H20D1611 (20L8D) for 25MHz boards and 
		   H20E1611 (20L8-7) for 33MHz boards.  The new PAL checksum is
		   57BE for both 25MHz and 33MHz boards.

                   This PAL may be ordered separately and will be sold 
		   separately.  The customer will be responsible for changing 
		   the PAL on the motherboard.  This will eliminate boards 
		   being shipped with the wrong PAL.

                   The only noticeable difference in motherboards with this 
		   PAL installed will be that the base memory will be limited 
		   to 512KB instead of 640KB and the overall memory is reduced 
		   by 128KB.