Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!utcsri!uthub!koko
From: koko@uthub.UUCP
Newsgroups: comp.sys.apple
Subject: Re: 6502-65C02
Message-ID: <442@uthub.toronto.edu>
Date: Mon, 4-May-87 01:03:51 EDT
Article-I.D.: uthub.442
Posted: Mon May  4 01:03:51 1987
Date-Received: Mon, 4-May-87 04:00:39 EDT
References: <8704281927.aa23754@SPARK.BRL.ARPA> <3021@ecsvax.UUCP>
Organization: CSRI, University of Toronto
Lines: 18

>                                                             65C02's cause
> problems on some //+ machines because of a timing problem.  The Rockwell
> 65C02's seem to work, as do the 65802's (most of the time).
> 
> Rick Fincher
> ranger@ecsvax

Also beware of regular NMOS 6502's.  If you have peripheral cards with
Rockwell or Synertek 6522's on them, Synertek 6502's will not work properly
with them.  (This may or may not be true, depending on the glue logic present
on the card.)  Only Rockwell 6502's will work.

The problem seems to stem from the fact that the phi1 and phi2 clock signals
available at the peripheral sockets are not the usual clock signals output
by the 6502 chip itself.  Instead they are complementary clocks generated by
the same circuit which generates the (external) clock signal supplied to the
6502 itself.  Therefore, the available clocks are about 50ns ahead of what
they would be if this were not true.