MOTM

John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com
Off Topic, but 74FXXX did work.  You just needed separate ground and power
planes and serious decoupling, virtually requiring 4 layer boards which
weren't all that common back then.

ABT and other recent logic is much better today.

Early Altera CPLDs were worse for ground bounce than F chips.  On the early
600, 900 1200 series Altera was recommending gray code counters (only 1 bit
transitions at a time) because their chips couldn't handle transition of an
8 bit counter from 11111111 to 00000000 without internal glitching.

I found a similar problem on a 1990ish AMI/Gould PLD.  Data glitch was
pattern sensitive.  I had to trace circuitry through half a dozen full
height racks to solve that one.  Switched to a similar Lattic part - problem
solved.  

John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com

> -----Original Message-----
> From: Paul Schreiber [mailto:synth1@...]
> Sent: Saturday, August 07, 2004 11:37 AM
> To: motm@yahoogroups.com; Bob Colwell
> Subject: Re: [motm] Re: YASDWB
> 
> 74Fxxx logic *never* worked. I think many TTL design carrers were derailed
> by
> those awful things.
> 
> The VC Pulse Divider will have 74ABT244 drivers on the outputs. Hardly any
> ground bounce at all (ground bounce  causes severe under-shoot in TTL
> edges).
> 
> Paul S.
> going digital this weekend
>