8 Feb
2010
8 Feb
'10
1:31 p.m.
-----Original Message-----
From: chd at chdickman.com
Sent: Sun, 07 Feb 2010 18:47:55 -0500
To:
Subject: Re: 6809 SBC
William Blair wrote:
Having learned assembly language programming on
the beautifully simple
architecture and instruction set of the 6800, the Byte magazine article
linked to below that I read when it was originally published really
impressed me. In the 6809 they made one of the earliest efforts I know
of to really tweak an already great uP instruction set based upon an
analysis of existing software:
http://tlindner.macmess.org/?page_id=119
I was introduced to the 6809 when I was at university and it just seemed
right. I came home and bought a CoCo2 and an EDTASM+ cartridge just to
play with it. I still have it.
Is there a source for 6829 MMUs? I would love to build a 6809 SBC with
an MMU that could run OS-9.
-chuck From what little I've managed to gather, the 6829
had some limitations that made it either difficult to use, or otherwise impractical for
many (if not most) applications. I've read someplace, for instance, that you
were restricted to four tasks. I suspect for that reason,
they're rarely seen. They were rare even in their own time.
A better approach, may be to create some hardware to emulate either
a Gimix or SwTPc style DAT (dynamic address translator). The key
element here, is that both of these are supported by some version
of OS/9.
-Jeff