[Coco] Checking/Testing a 68B09P

[David J. Cooper]

I've become out of control.  When I travel on business I look for the local
electronics recyclers to see if they have anything I might want.  Is this
nuts or what?  (yes, it's nuts).

Well, I'm not sure how to test them, but if you decide you don't want them
I'll have a good home for them.  I have a couple of vectrex's that I think
have dead processors.



----- Original Message ----- 
From: "Andrew" <keeper63 at cox.net>
To: <coco at maltedmedia.com>
Sent: Sunday, July 01, 2007 10:20 AM
Subject: Re: [Coco] Checking/Testing a 68B09P


> All:
>
> Yesterday, I picked up a set of 6809 40-pin DIP processors (from a local
> Phoenix electronic junkstore - Apache Reclamation and Electronics). I
> wondered if anyone could tell me whether they are worth keeping or not,
> plus if there was a way to test them without using a real CoCo?
>
> Of the lot, I have 6 pieces of HD68B09P, and one MC68B09P (I also found
> a wierd floppy drive controller chip - FDC1795 - does anyone know
> anything about this - I found a datasheet, but I am wondering if it
> could be useful for building a more modern FDC board for an Altair I
> have sitting waiting for restoration?).
>
> I found data sheets for all of these parts - so, for the 6809 pieces,
> they seem to be 1.5 MHz processors (B), plastic (P) - HD=Hitachi,
> MC=Motorola. The spec sheets seem to be for all 6809 products, and they
> say they are pin-compatible.
>
> Unfortunately, none are of the 2 MHz variety for the CoCo 3...
>
> They seem like they might make a good upgrade or replacement CPUs for
> the CoCo 2 (they may even work in a CoCo 3?) - however, I don't know
> what the condition of these chips are - they were stored on anti-static
> foam, but were contained in a large mix of "junk" parts. None were
> labeled as bad, but that doesn't mean anything.
>
> Does anyone know how I could test these to verify that they work? I have
> both a Color Computer 2 and 3, but I don't want to smoke these units
> (they are my first computers from my youth - I try to take good care of
> them).
>
> Is there any way I can build a simple perfboard test circuit that could
> tell me "likely good"/"likely bad"? The datasheets don't give a sample
> circuit (I suppose there is actually an "applications" datasheet or book
> for 6809 reference designs?). I suspect that the simplest test design
> might actually be quite involved - the 6809 is a microprocessor, after
> all, and not a microcontroller - so I can imagine a bit of support
> circuitry to be required.
>
> I am not at a point where I can do this immediately, but knowing what to
> do when I can get around to it would help.
>
> Thank you!
>
> -- Andrew L. Ayers
>     Glendale, Arizona
>
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