Re: 6809 in a C64

From: Michael Brant <brant.michael.l_at_gmail.com>
Date: Wed, 23 May 2018 09:26:16 -0400
Message-ID: <CAGJGKwjmHdY2_ANNtJg2gAXgBFrN7JRqOeMvwpMC=OoQRY9z3g@mail.gmail.com>
Jim, I almost got confused and thought I was reading the coco mailing
list.  Lol this is quite interesting.

On Wed, May 23, 2018, 2:11 AM Jim Brain <brain@jbrain.com> wrote:

> Ruud:
>
> In reference to this old posting:
>
> http://www.softwolves.com/arkiv/cbm-hackers/13/13116.html
>
> I thought I'd note that I designed a C64 cartridge containing a MC6809 and
> some RAM.  I know it's not exactly the same as your idea, but it is easier
> to prototype.
>
>
> https://www.facebook.com/go4retro/photos/a.386509271508869.1073741826.386509238175539/984731561686634/?type=3&theater
>
> The initial goal is to multiplex the two CPUs, allowing the 6809 to access
> some shared RAM on the low PHI2 portion of the cycle, and 64 access on the
> high portion.  Then, I'll try to speed up the 6809 to 4MHz and see if I can
> keep the shared memory in place.
>
> Possibly later, I'll see if I can have the 6809 take over the bus like
> SuperCPU and Chameleon64, but I suspect I have to learn quite a bit more
> about the system bus.
>
> Jim
>
> --
> Jim Brainbrain@jbrain.com www.jbrain.com
>
>
Received on 2018-05-23 16:00:43

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