RE: Introduction

Date: Wed, 29 May 2013 20:56:37 +0200
Message-ID: <000901ce5c9e$3fdbca40$bf935ec0$@org>


To tell the truth, I don’t know if it’s a good example J

I’ve never seen a cp/m board or ms/dos board really working on Commodore 

(I mean 1980-1985  c64/CBM 8032/CBM II)


The 3 boards I tried where horribly slow and unreliable L


The 6809 was a great processor, very nice to program.

I recently used a 6809/Flex on a xula board, it was really fun

I would love to use it on my sx64 J






De : [] De la part de Steve Gray
Envoyé : mercredi 29 mai 2013 19:23
À :
Objet : Re: Introduction




I understand #1.. I'm learning electronics myself. By now though you might be ready for the next step. Since the 6510 supports the ability to be disabled and the cartridge port has all the correct signals you might consider making a cartridge for the C64 version. Take a look at the schematics for Commodore's CP/M cart for an example of how another CPU can take over the system.


As for #2, if you design a cart then it will work on all the different C64 revisions, including the SX-64 and maybe the C128. This would appeal to many more Commodore owners I'm sure.


On the other hand I love the CBM-II machines and a 6809 cpu would be a cool project for it too. The advantage of the CBM-II's is they can have up to 1MB of ram! Unfortunately they have no colour or graphics capabilities (as an aside, I hope to design a colour addon for it).


I have many systems (C64, SuperPET, Atari, Coco). If I can help let me know.




From: Boisy Pitre < <>>
To:  <> 
Sent: Wednesday, May 29, 2013 11:01:18 AM
Subject: Re: Introduction


Thanks for your comments.


The Liber809 for the Atari completely replaces the 6502 with the 6809. This was done for several reasons:


1) Simplicity of design. It was my first hardware project, so I wanted to minimize risk.

2) Physical size. The Liber809 was intended to be used in multiple Atari A8 systems, all of which have different board layouts and clearances. Making the Liber809 as physically small as possible was important to allow it to fit easily in the most systems.


I think there would need to be some support for I/O lines because of the NitrOS-9 operating system which I would intend to port to a 6809-equipped C64. NitrOS-9 wants as much RAM as possible. and so it would be necessary to switch in/out the ROMs.







On May 29, 2013, at 4:42 AM, Michał Pleban <> wrote:


Boisy Pitre wrote:

My main interest is in adapting the 6809 to the C-64 like I've done with =
the Atari A8s ( <>  <>)
I've done a bit of research on what may be needed to do this, =
specifically with regard to the 6510 and its built in PIA port. I'm =
wondering what the interest level for something like this would be.

That sounds interesting. I cannot figure from your blog, whether you run
6502 and 6809 concurrently, or do you replace the 6502 CPU completely
with 6809?

With regard to the I/O lines of the 6510, as Ruud pointed out you don't
need them as long as you're happy with default memory configuration and
no tape support. But as I see you are running some advanced operating
systems on the machine, you would probably like to utilize full RAM of
the machine.

You could possibly sacrifice the User Port to drive these pins.
Otherwise you need to carve some address space for an IO controller
which would drive them.


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Received on 2013-05-29 19:00:03

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