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Re: Unusual Apple // card
- Subject: Re: Unusual Apple // card
- From: david@uow.edu.au (David Wilson)
- Date: 24 Mar 2002 15:16:17 +1100
- Newsgroups: comp.sys.apple2
- Organization: University of Wollongong
- References: <PXiaPESWbbJ=Z9t+x362ac4HTdmS@4ax.com> <a7iv33$rbl$1@venus.itns.co.za>
- Xref: archiver1.google.com comp.sys.apple2:18377
Stephen Shaw <xstephenx@apple2.org.za> writes:
>The 6821 is for the 6809 series of processor. The 6809 was similar to the 6502
>so it will work with an Apple. At a guess I'd say it is similar to a 6551 VIA.
>6821=6551????
6821 is Motorola PIA (improved version of 6820) for 68xx family (6800/6809/etc)
6520 (I think - could be 6521) was the 65xx family equivalent of the 6820/6821
6522 is the VIA - no 68xx equivalent
6551 is an ACIA (improved version of 6850 I guess - not pin compatible)
--
David Wilson School of IT & CS, Uni of Wollongong, Australia