AMI TECH TIP


TECH TIP NO.        TT39.004

DATE:               September 16, 1991
BOARD TYPE:         Baby Voyager, Series 39
BOARD REVISION:B
BOARD FREQUENCY:    N/A
ORIGINATOR:         Umashankar Mondal
RELEASED BY:   Documentation Control


Internal Cache Modification

All Baby Voyager Boards with ECN 001/ECN 002 could have problems with
I/O cards that are accessing memory locations in the E0000h - EFFFFh
address segment.  This is because in ECN 001 and ECN 002 level boards,
this area is cached in the 80486 internal cache.  This problem might
appear with a number of serial intelligent I/O controllers for UNIX as
well as certain communication cards, etc.

The modification generated by ECN003 does not allow the contents in the
E0000h - EFFFFh address segment to be cached in the internal cache of
80486.

The PAL change at location U43 is:

     ECN001/ECN002       ECN003 
     
      G00E3902           G10E3902.