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From: ix469@sdcc6.UUCP (david smith)
Newsgroups: net.micro.apple,net.micro.68k
Subject: Re: 68000 vs 6502 (!)
Message-ID: <2230@sdcc6.UUCP>
Date: Sun, 6-Oct-85 14:39:46 EDT
Article-I.D.: sdcc6.2230
Posted: Sun Oct  6 14:39:46 1985
Date-Received: Tue, 15-Oct-85 10:50:58 EDT
References: <151@uvicctr.UUCP> <7100003@prism.UUCP> <596@sftig.UUCP>
Reply-To: ix469@sdcc6.UUCP (david smith{|ix})
Organization: U.C. San Diego, Academic Computer Center
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Xref: watmath net.micro.apple:2231 net.micro.68k:1236

The 65816 is indeed pin-compatible with the 6502 and it may be
possible to "drop" one into an Apple II without major problems,
provided you don't want to address more than 64K.  In order to
address the 16 megabytes, Western Design uses the data bus as
address bus for the half CPU cycle that the data bus is not used.
Unfortunately, during the time, the video is busy playing with
things.  I believe that the MMU switches the CPU off the data bus
during that time.


==================
David L. Smith
UC Sandy Eggo
{ucbvax, ihnp4}!sdcsvax!sdcc6!ix469

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