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Path: utzoo!watmath!watnot!thfisher
From: thfisher@watnot.UUCP
Newsgroups: comp.sys.cbm
Subject: Added RAM at $DE00 on C64
Message-ID: <12450@watnot.UUCP>
Date: Thu, 12-Feb-87 14:52:50 EST
Article-I.D.: watnot.12450
Posted: Thu Feb 12 14:52:50 1987
Date-Received: Fri, 13-Feb-87 05:39:56 EST
Reply-To: thfisher@watnot.UUCP (Terry Fisher)
Followup-To: thfisher@watnot.UUCP (Terry Fisher)
Distribution: na
Organization: U. of Waterloo, Ontario
Lines: 14
Keywords: C64,RAM,DE00
Summary: Problem with writing to multiple bytes


I am having a problem with the expansion port of the C64. The interface I have
made puts 256 bytes of RAM in the I/0 1 block ($DE00 to $DEFF). I am using 
HM-6116 chips with 150ns access time. When I write to location $DE09, the
information at location $DE49 sometimes changes with it. I have tried several 
different chips, but the problem persists. Writing to other addresses does not
seem to create the situation.
 
I would really appreciate any suggestions on how to correct this problem, or 
what is causing it. 

Terry.

{watmath,alberta,ubc-vision}!watnot!thfisher