[Coco] 68B09E on coco2

[Zippster]

There is often a little confusion when dealing with 6809 variants.

There are 2 main types.

	MC6809 = internal oscillator
	MC6809E = external clock

They have different pinouts, and aren’t interchangeable, though they
run the same code.

The speed rating is designated by a letter 68x09 (or lack of one).

	6809(E) = 1mhz 
	68A09(E) = 1.5mhz
	68B09(E) = 2mhz

CoCos use the “E” type.  Of course it’ll need to be fed a faster clock
to go faster.

A genuine MC68B09E will work in a CoCo2, I’m running a couple.

I bought some from Utsource which are fine.

- Ed


> On Feb 8, 2015, at 1:44 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.
> 
> 
>