Re: Hardware emulation of 6509 using 6502?

From: Mia Magnusson <>
Date: Thu, 26 Jul 2018 03:13:08 +0200
Message-ID: <>
Den Tue, 24 Jul 2018 19:11:01 -0500 skrev Jim Brain <>:
> On 7/24/2018 5:35 PM, Mia Magnusson wrote:
> >
> > I realize that you at least anyway need to imput all address lines
> > to decode $0/$1, so that won't be any problem.
> All address lines are sent to the CPLD.
> >
> > Are any address lines (except the bank lines) going through the
> > CPLD or do they just also go directly from CPU to CPU socket?
> They currently do in v4.  In v3, I ran A13/14/15 through the CPLD, in 
> hopes of doing some translation, but there is not enough CPLD room to
> do so, and the '816 makes this a useless effort.

Oh, with the address lines not passing through the CPLD it's probably
best to skip my idea. The other option to solve this would be to have
some gates that can force the relevant address lines to the wanted
state (i.e. the 2k video memory block in bank 15 on the B) but that
might be a bit excessive unless the product should be sold as a combined
6509 replacement, 65816 accelerator and PET emulator 3-in-1-combo.

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Received on 2018-07-26 04:00:04

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