Student "edition" found at {csi dot journalspace dot com}.

Maybe I shouldn't have started this blog now, not with everything that's been going on.

In the first meeting of my Computer Systems Organization lecture class for the tenth week of the third term, since this was the meeting right after their lab class where they first encountered the clock pulse in the flip-flop circuit they constructed, I had to clarify some of the misunderstanding and confusion that I got as feedback from that hands on session about how the circuits they built worked.

First, I detailed using the two dimensional voltage and time graphical view when exactly the values of the outputs of the flip flop change depending on whether it is the clock pulse that goes from positive to negative or it is the input.

I also gave an extended truth table of the inputs and outputs of that flip flop, including when the clock pulse is positive and when it is negative.

So afterwards, theoretically the students were supposed to be clear already on why their circuits were incorrect when the complementary outputs were lit at the same time or both off, even when their input is not the type that is supposed to generate the invalid output.

From there I went to the discussion of the master slave flip-flop, where there are more than one flip-flop that is connected in sequence.

I only used the RS flip-flop to demonstrate this, telling the class that the reason for making a sequence of flip-flops where the output of the first flip-flop becomes the input of the second flip-flop is to ensure that the one remaining invalid input is never set.

Even if invalid input is placed on the first flip-flop, and results in a non-complementary output for the first flip-flop, it is not considered as invalid input anymore when it becomes the input of the second flip-flop.

That means the second flip-flop will never have an invalid output.

So even though the definition of input-output becomes easier, the construction of those simpler circuits actually becomes more complicated.

Session 1043 had outputs that are non-complementary. Class dismissed.