The bad news is that to create a succesful design using real-world IC devices one must understand the limitations, and allow for them. THAT probably has a lot to do with the number of folks unable to design digital circuits that perform as intended. I have never had problems with R/S FFs because of that limitation.

SEriously!, there is a valid reason that the manufacturers of those digital logic IC devices publish those data sheets with all of those boring numbers on page after page. ALL of their production facilities are located in THE REAL WORLD, which means they suffer from real world limitations. This places a burden on all of those folks who choose to be logic hardware circuit designers: They can only use real world components! Finite propogation delays and setup times.
AND the insidetheblock circuits for logic circuits shows us that they are not as simple inside as it seems. THAT part is where the long explanation gets really technical, and talks about details that are seldom discussed.

DATA SHEETSare our friends!! They keep those of us who study them from looking like we have no clues.

The data sheets are also always incomplete -- it pretty much has to be this way. They don't provide specs for every conceivable parameter that people might need, let alone provide them over a range of other parameters (most parameters are only spec'ed under very closely controlled test conditions). If they did spec every parameter, the data sheets would be many times longer and the parts would cost considerably more. So we are left reading between the lines and invoking those crystal balls we all hate so much. Is a parameter not there only because they decided that its usefulness was too limited to be worthy of inclusion? Is it not there because they just didn't think of it? Or is it not there because it would only have meaning in a context that they don't think should ever be applicable? In the case of S and R asserted simultaneously, they don't say what happens if they are de-asserted at the same time (nominally). Why not? It these signals might often come from asynchronous events, it is far fron inconceivable that they are registered signals, which means that it is very likely that in such applications if they are both asserted that they could be relaxed at the same time. Yet they don't spec what the minimum time from one being relaxed to the other being relaxed in order to ensure that the second one is the one acted upon. Why not? Perhaps it's as simple as them taking the position that if you design a system in which this is important, that you have a poorly designed system.

 

My experience with the data sheets that I have used is that they are quite helpful towards avoiding problems. I can not account for the experiences of others.

 

My experience with the data sheets that I have used is that they are quite helpful towards avoiding problems. I can not account for the experiences of others.

Extremely useful!

There are certainly times that I wish they had more information than they do. When it's because I'm trying to do something out-of-the-ordinary, I'm sympathetic to the fact that it's unreasonable to expect them to provide information this is for out-of-the-ordinary applications. On a few occasions, I have been trying to do what I thought were very much "ordinary" things and the information I thought I needed wasn't there. That got me to take a step back and come at the situation from a couple of different angles. Either what I was trying to do wasn't, in fact, "ordinary", or else it was and I was thinking I needed information that, in fact, I didn't. Sometimes it turned out to be one and sometimes the other, but either outcome made for a useful learning experience.

 

I have seen the statement that "not following the recommended application use may result in unanticipated action."

 

I have seen the statement that "not following the recommended application use may result in unanticipated action."

I haven't seen that note, but not surprising. It's essentially the same as "undefined behavior" in a programming language. In either case, if you don't adhere to the specs, you can't complain about anything that happens as a result.