[coco] 6309 speed

[jdaggett at gate.net]

Gene 

What you may also be seeing is supply noise or transients when 
other circuts are switching. The noise or transient is transferred via 
the power runs and could causing the output current sources to 
glitch. This would then be seen as glitches when the output 
transistors switch. The only way to cure that is to better isolate 
internal current sources from the internal power bus or to beef up 
power runs to some of the under supplied current sources that are 
noisy. Would mean a die change and maybe it was done and may 
be not.


james


On 3 Aug 2005 at 22:30, Gene Heskett wrote:

Date sent:      	Wed, 03 Aug 2005 22:30:26 -0400
From:           	Gene Heskett <gene.heskett at verizon.net>
Subject:        	Re: [coco] 6309 speed
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> Which is why I mentioned the glitches on some pins early in the cycle.
>  If those are going to represent a fixed delay from the clock pulse,
> then I can see problems well before 30 mhz, possibly as low as 8 or 10
> mhz.  IIRC, they were about 30-45 ns after the clock edge, but I don't
> recall which clock or which edge now.  At the current speed, they are
> rather benign, and any ttl buffering done will probably gobble them
> up.  They aren't full swings by the time they get thru the buffering
> in the late mpi I have.