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 my first lecture meeting with the students of Computer Systems Organization, which happened on the latter part of the third week of classes, I taught them about getting the complements of Boolean functions, which I know had been discussed by their previous teacher.

Using some of the theorems on simplifying Boolean functions, particularly De Morgan’s, I had them come up with a function for the inverse of the original function.

Then, applying the definition of the inverse, which is that all the ones become zeroes and vice versa, we verified the new function that they got.

We had a few examples, and after a while we went to K-mapping, starting with the simplest: two variables or inputs.

For some of these they only had to invert some of the basic gates that we had. For others, they could see that it was supposed to be just following one input or the inverse of one input, and disregarding the other.

That left some one high or one low value configurations which I taught them how to determine using the K-map.

First they had to learn how to place values from the table to the two-by-two grid. From there it was another step to determine what the groupings on the grid, in certain arrangements of exponents of two descending, translated to in function form.

There seemed to be no problem with two inputs, so we went to three inputs or variables, which required a two by four K-map.

We used the earlier functions in the complements section, and although it was somewhat clear to them, we stalled when we ended up with a function that was different from the first one we got, which was a sum or products instead of a product of sums.

To go back to the theorems on simplifying functions, or in this case proving two functions have the same outputs, I believed would have strained their brains. So I just gave them an exercise on complements instead.

Session 965 uses only one input to determine the output. Class dismissed.