[Coco] Oscillator Circuits needed for EF68B09P 2MHZ versions I recently received

[Computer Doc]

Dear All,

Thank you John Kent for that acute observation! :)  I appreciate it.  I
should have noticed that, but for some reason I didn't.   I have been
looking for several days, since receiving your email, for the datasheet for
Thomson's EF68B09P chip, but I can't seem to locate one.  I want to build
Grant Searle's 6-Chip 6809 Computer as my first 6809 project since it has
the fewest parts count for any 6809 computer running Basic that I have ever
seen!  I'm not a Computer Electronics Engineer, but I love to learn from
other people's projects and then modify them for what I think might be
interesting.  The datasheet for Motorola's MC6809 processor utilizes a
crystal connected to pins 38 & 39 along with two capacitors connected from
each pin to ground as you all know.  I could not find any new MC68B09P chips
anywhere, so when I spotted the EF68B09P chip on ebay, I went ahead and
ordered it thinking it used a crystal also.  Since the EF68B09EP doesn't,
maybe the EF68B09P doesn't either.  So for right now, I have two EF68B09Ps
that I can't use yet.  Any help finding the datasheet on the EF68B09P
version would be much appreciated.  Evidently I've not yet found the "magic"
6809 part number for the search engine to locate it.  I can't hardly wait to
start building it.  Have a good day everybody. :)

Kip

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of John Kent
Sent: Sunday, June 03, 2012 2:51 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Oscillator Circuits needed for EF68B09P 2MHZ versions I
recently received

Althought the link suggests the data sheet is for a EF6809P, the png image
on the web site says EF6809E. Often the datasheet web sites get their data
sheets mixed up. As Gene said the 6809E requires external clock generation
which might be what you were referring to. I didn't want to have to register
with the site to check which data sheet it was.

The 6809E need an external quadrature (90 degree phase shifted) clock, to
generate E and Q signals which might be what you were referring to. 
Typically you use a 4 X clock and a dual JK flip flop to get the phasing
right. The 6800 is a little different in that the clock signals are 180
degrees out of phase and must not over lap i.e. the two phases should never
be high at the same time.

John.

On 3/06/2012 2:36 PM, gene heskett wrote:
> On Sunday, June 03, 2012 12:33:45 AM Computer Doc did opine:
>
>> Hi All,
>>
>>
>>
>> I recently ordered a couple of EF68B09P chips thinking their pinouts 
>> were the same as Motorola's MC68B09P chips.  I just downloaded the 
>> datasheet for it and they are very different, almost like their 
>> version of the 2MHZ 6809 used some of the original 6800 clock circuit 
>> specifications. Look at the pin labels.  They remind me of the 6800's 
>> pin labels.  What do you think? The following link is the one I used 
>> to get the datasheet:
>>
>>
> The chip used in the coco's would be the MC6809EP, where the E means 
> external clock generation, and of course the P means the epoxyB 
> plastic case
>> http://www.datasheetdirect.com/part/EF68B09P.html
>>
>>
>>
>> As you can see on page 13 (as Adobe reader counts it) and page 1-162 
>> (as it is printed in the PDF file, the clock circuit is quite
complicated.
>> Does anyone have a much simpler clock circuit using a 2 lead 8MHZ 
>> crystal or 4 pin 8MHZ Oscillator (metal case)?  Thanks guys in 
>> advance for your input. You all are always forthcoming with 
>> information.  I appreciate it.
>>
>>
>>
>> Kip
>>
>> Cheers, Gene

--
http://www.johnkent.com.au
http://members.optusnet.com.au/jekent


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