Hi There are other devices where a simultaneous set and reset will toggle the device.
Since the "useful" operating point is simultaneous inputs, what you are building is a metastability tester. Bob On Dec 9, 2012, at 5:00 PM, Hal Murray <hmur...@megapathdsl.net> wrote: > > li...@rtty.us said: >> The flip flop would have a metastable region. It would be quite narrow, but >> it would be there. As soon as you try to take the square wave into the >> processor, you are right back to the same problems we've discussed before. >> The flip flop, run this way does not improve that part of the situation. > > That's not the issue I was trying to bring up. > > The problem is that set and reset on most FFs are asynchronous. You have to > look at the fine print in the data sheet to see what happens if they overlap. > Consider the 74x74 that I looked at. It has true and compliment output > pins. If set and reset are both active, both outputs go high. So if the > reset signal comes first, you might expect the FF to get turned off, but with > that chip, the FF will be high. > > (A few FFs have synchronous set and reset, but since there was no mention of > a clock, I assume we are talking about asynchronous inputs.) > > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.