I wonder why
Insufficient preliminary research is a reason for closing a question (referring to internal circuitry of IO ports in MCU).
update: The question has been reopened.
update: The question has been re-closed.
The down-vote popup says "This question does not show any research effort; it is unclear or not useful", so
Insufficient preliminary research as far as I see is more of a cause to down-vote a question rather than close it.
I don't see anywhere in the help center to say that these kind of questions are not allowed (like "you are not allowed to ask unless you have already searched and were not able to find the answer"), and even then you can never be sure if the OP already tried to find an answer but just wasn't able. Not everyone has the same ability when it comes to digging up info.
I've seen several simpler questions (e.g transistor as a switch, or led resistor type of questions) that could easily be answered with a google search, but no one accused them of having "Insufficient preliminary research".
In essence I think it it quite hard to find a question that has not been asked already in some forum and can't be answered just by a google search . Based on that almost every question fits the previously mentioned reason to be closed.
P.S. I'm sure that this question will be down-voted several times but I still believe it's worthwhile sharing my view.
I just saw this question Wattage Rating for these Zeners (I didn't search for it, it just appeared to the top of active questions).
I wonder why wasn't that question closed as well with insufficient preliminary research. The reply for the question asked is already in the description of the design so he obviously didn't bother reading it.
A quick calculation example for the zener rating and resistance are in order, so it is properly understood. The maximum zener current for a given voltage is easily calculated ...
I repeat here what I said in one of the comments below:
I can understand the insufficient preliminary research (or too easy to find an answer) as a cause to make some members walk away from a question (not being motivated to help) and I totally agree with whoever feels this way, but in no case this can be a reason to prevent others who want to reply to do so (like when the question is closed).