Re: Hardware emulation of 6509 using 6502?

From: Mia Magnusson <mia_at_plea.se>
Date: Fri, 16 Mar 2018 23:57:07 +0100
Message-ID: <20180316235707.00005034@plea.se>
Den Fri, 16 Mar 2018 09:42:06 +0000 skrev smf <smf@null.net>:
> On 15/03/2018 23:22, Mia Magnusson wrote:
> > (and in the long run also replace the 6525 with something easier to
> > find).
> 
> A CPLD and buffers looks the easiest solution to me.
> 
> http://archive.6502.org/datasheets/mos_6525_tpi.pdf

If you want to emulate the possibility of individual DDR for each pin,
it seems easier to use 6821 (which afaik is still possible to source
new from reasonable sources) for the standard I/O pins, while using a
CPLD or similar for emulation of the interrupt controller logic and all
other stuff that's not part of the simple I/O function.

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Received on 2018-03-17 00:00:02

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