[Coco] 68B09E on coco2

Arthur Flexser flexser at fiu.edu
Sun Feb 8 03:38:14 EST 2015


To elaborate, all the pokes on the page you cite should almost certainly
work as well on a 1 MHz 6809 as on a 2 MHz one.   Though you lose video on
the non-address-dependent one on a CoCo 1 or 2 (but not on a CoCo 3.)

Art

On Sun, Feb 8, 2015 at 2:44 AM, embsys dev <embsysdev at gmail.com> wrote:

> After reading this
>
> http://www.cs.unc.edu/~yakowenk/coco/text/speed.html
>
> I understand what is technically possible, what is useful, and the
> underlying reasons why.
>
> Can anybody confirm that a *genuine* MC68B09E *should* boot a coco2 at
> 0.89M?  If that is so, then it seems reasonable to conclude my chip is
> mislabeled and order another from somewhere else.
>
>
>
>
>
>
> On Sat, Feb 7, 2015 at 10:39 PM, Arthur Flexser <flexser at fiu.edu> wrote:
>
> > I know of no advantage to using a 68B09E in a CoCo 1 or 2.  It does not
> > allow "stable operation at 1.7 MHz".  The video at that speed will be
> just
> > as unstable as with a regular 6809.
> >
> > Art
> >
> > On Sun, Feb 8, 2015 at 12:11 AM, embsys dev <embsysdev at gmail.com> wrote:
> >
> > > coco2, 26-3026 (socketed chips, melted kbd), 64k ram.
> > >
> > > I recently bought an MC68B09E from Jameco, but when I swapped it in
> all I
> > > got was interesting colors and patterns, no sign on.  I understood
> > (perhaps
> > > wrongly?) this was a drop-in upgrade that would allow stable operation
> at
> > > 1.7MHz.  I noticed some list discussion about Jameco having mislabeled
> > > chips,  any way to rule this in/out by inspection?
> > >
> > > Comments and advice?
> > >
> > > Thanks,
> > > Darryl
> > >
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> > >
> >
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> >
>
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