Re: Hardware emulation of 6509 using 6502?

From: Mia Magnusson <>
Date: Wed, 25 Jul 2018 00:35:50 +0200
Message-ID: <>
Den Mon, 23 Jul 2018 19:03:01 -0500 skrev Jim Brain <>:
> On 7/23/2018 3:53 PM, Mia Magnusson wrote:
> >
> > I'm not sure if my idea is any good, but if it won't add any
> > noticeable cost to the final product it might aswell be added. I'm
> > not sure who might be prepared to patch a PET kernal for this
> > though.
> Adding any functionality carries a cost in complexity and regression 
> testing.
> I would counter, for the above, that any such functionality can be
> added later once a plan is identified.  That's the beauty of CPLDs

Yeah, as long as enough of the address bits pass through the CPLD. I
think A11-A15 needs to pass through the CPLD to be able to remap screen
memory for PET emulation.

I realize that you at least anyway need to imput all address lines to
decode $0/$1, so that won't be any problem.

Are any address lines (except the bank lines) going through the CPLD or
do they just also go directly from CPU to CPU socket?

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Received on 2018-07-25 01:01:55

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