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 thirteenth week of the third term (which also happens to be the second to the last meeting for the entire term before the finals) there were some students who were asking, or more accurately complaining that we shouldn’t have class for that period anymore.

I don’t know if they were just filled to the brim with everything we have taken up so far (as well as those discussed in their other subjects) but I definitely needed closure in my curriculum, so I wrote emphatically on the board “LAST TOPIC” before proceeding to quell any more negative reactions.

This was how to power up and use a seven segment display, using non-sequential counters.

Each segment of the display was given a corresponding letter, and a seven-bit state label was drawn up for each single digit that had to be produced, and from all of these a circular state diagram was made.

Then a list of the inputs needed if the states were to be produced for D flip-flops and JK flip-flops was filled, and from this combinational sub-circuits from the present state slash output bits to the inputs were made.

Even though this resulted in a one hundred and twenty eight cell K-map, all but ten of those were really don’t care fields, which made their job of grouping easier.

In fact, in the example I gave, I was encircling groups as large as sixty-four bits at a time, which resulted in terms for the final function that only had one variable out of the seven, although sometimes it was inverted or primed.

It also made their function so much easier that they only had to group the less than ten ones in the whole field, resulting in less than ten terms, which they would not have thought possible with a regular seven-variable K-map.

I gave the functions and sub-circuits of the next six segments for the display to them as an assignment to be submitted on the last meeting.

Session 1069 is “don’t care”. Class dismissed.