[Coco] ceramics ...

[jdaggett at gate.net]

Kevin

The 68x09 differs from the 68x09E parts. The 68x09 has an internal 
oscillator and quadrature phase generater. A simple but effective 
quadrature phase generator is a two D flip flops.  This also divides 
the the clock by 4. That is why many two phase Motorola processors 
have the crystal speced at four times the buss frequency.

james


On 5 Sep 2004 at 12:29, Kevin Diggs wrote:

Date sent:      	Sun, 05 Sep 2004 12:29:14 -0700
From:           	Kevin Diggs <kevdig at hypersurf.com>
To:             	CoCoList for Color Computer Enthusiasts 
<coco at maltedmedia.com>
Subject:        	Re: [Coco] ceramics ...
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> Hi,
> 
>  Now I'm confused. Can you clarify this 12 MHz 3 MHz buss thing?
> 
>  I thought that square on my PIII was the die! Amazing it can take the
>  
> pressure that the heat sink puts on it! I have this Thermaltake orb
> heat sink. Under Linux I can build Mozilla with the fan unplugged and
> it does not burn up the chip. The heat sink does get hot though. It is
> not to hot to touch. It is uncomfortable though.
> 
>      kevin
> 
> jdaggett at gate.net wrote:
> > Mark
> > 
> > Heat, Heat, Heat
> > 
> > Also Mark the design that we used the 6809 in was to transmit
> > digital data stream. We needed to boost the transmit speed and found
> > that raiseing the clock speed on a 68B09 to 12 MHz (3 MHZ buss) from
> > 8MHz (2 MHZ buss) allowed us to do that. Otherwise we needed to
> > redesign the whole test equiptment. We used about 1000 of them
> > worldwide. The cycle time and cost to redesign them with a new
> > processor versus taking the risk of increase buss speed was a
> > calcualted risk but a reasonable risk. A few phone calls to the
> > right people and the right questions were answered and we undertook
> > the course of action that we did. It worked. Will it work on
> > everything? No. But we did not just go out and drop in a new crystal
> > and prayed.   
> > 
> > Now the heat sink litterally sits on the backside of the die. 
> > 
> 
> 
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