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.

On the three-hour session of my Computer Interfacing Systems class for the seventh week of the second term of the school year, we continued with the same experiment from last time, performing more trouble shooting of why their circuit and program would not work.

This included determining what the voltage was that was being sent out by the inputs to the parallel port as well as the bits that were supposed to tell the computer that there was data waiting to be read.

From what I saw, the voltage reading was below the five-volt limit that would have been considered by the system as active high. No wonder their signals weren’t getting recognized by the computer.

This was due to the resistors that they still placed as part of the input, even though they were already sending in exactly five volts from the DC power source.

There was also the possibility of just getting the input voltage from one of the signals that the parallel port itself was sending out, instead of from a different source. This would assure that the voltage being received by the computer was one that it would specify as high or one.

Another factor was the fact that the students used the parallel port data memory address for testing if their decimal to binary software converter was working, when they could actually bypass the “write to parallel port” and “read from parallel port” commands, which, of course, screwed up with the status bits of the port, especially since they didn’t clear or reset it at the start of the program.

I hope that they will be able to finally get it running next meeting, which is actually two weeks from now.

In my Graphics Two manual drafting classes, I gave them two new plates; these ones about getting the isometric view from the orthogonal projections that had hidden lines.

This time I did not bother with coming up with new designs for the second and later class, although the students were already expecting it and – when they were early and arrived in the room before the first class finished – waited for me to return from a short errand in the faculty room to tell them if I would be giving them different objects.

This is a major difference I see between the freshmen and the upperclassmen. The upperclassmen would have insisted on what they wanted, which was making the plates they already knew were easy instead of waiting to see new plates that are potentially more difficult.

Session 829 sends low voltage here. Class dismissed.