[sdiy] 4027 flip-flop weirdness

[Tim Ressel]

I had an issue like this with rotary encoders. The edges of the "square" waves were too slow, causing the downstream logic to act very funny. The solution was to put in 74HC14 schmitt trigger inverters. Cleaned the edges right up, and the problem went away. CMOS is very picky about edges.

--TimR


--- On Tue, 3/10/09, Karl Ekdahl <elektrodwarf at yahoo.se> wrote:

> From: Karl Ekdahl <elektrodwarf at yahoo.se>
> Subject: Re: [sdiy] 4027 flip-flop weirdness
> To: synth-diy at dropmix.xs4all.nl
> Date: Tuesday, March 10, 2009, 8:01 PM
> > According to the data book I  have the clock needs to
> > transition in under 5 us.  How exactly are you doing
> > your debouncing?
> 
> Hmm maybe this is my problem, i did a lowpass with 27K /
> 1.8nF and a 1M to ground for discharge. That is 0.3mS charge
> and 11ms discharge... 5uS - is that enough time to debounce
> a mechanical switch?
> 
> Karl
> 
> 
>      
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