Re: Weird /KERNAL line on old boards

From: silverdr_at_wfmh.org.pl
Date: Tue, 10 Jul 2018 19:54:05 +0200
Message-Id: <A306850D-BE7F-4689-8331-047E6425F83B@wfmh.org.pl>
> On 2018-07-09, at 00:59, Nejat Dilek <imruon@gmail.com> wrote:
> 
>> Or require a longer _KERNAL pulse than this false pulse?
> 
> How? I use this pulse to interrupt an attiny85. Even if I check for
> the signal again in the interrupt it's all open to every kind of race
> conditions since this false signal pops up quite randomly (unless
> tamed) before and/or after intended access.

As long as the assumption is that valid pulse is always longer than the longest spurious one, you can use the "software debouncing" - similar to what is sometimes used to debounce relatively fast switches, without adding significant capacitance, Schmitt triggers, etc. I used it more than once with good results.

> Side note : I don't want
> to code this in assembly, I prefer C if I can :)

It can be done in C :-)

> Any other hardware means to filter out 41nsec pulses from 500nsec
> pulses by the way? (Hmm, maybe using some logic gates with >41nsec
> propagation delays)

I'd say the software method is cheaper and should do as well.

-- 
SD! - http://e4aws.silverdr.com/
Received on 2018-07-10 20:02:23

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