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 Circuit Fundamentals lecture class for the fifth week of the first term, I lectured on a second interrupt (and in fact, a third) this one dealing with keyboard services.

The first function of this interrupt was to get a character from the keyboard, but unlike the previous interrupt we learned, this is before the character is displayed on the screen. Then I had to teach them a new command to display the character in the keyboard buffer to the screen.

Talking about the keyboard, this is when I had to describe to them the existence of the keyboard buffer, which functions like the stack in their assembly language programs except that it is first in first out not first in last out.

The second function was to determine if a key had been pressed, or in machine terms, if the keyboard buffer was empty or not. The result of this was placed in the zero flag, so its status could be accessed by using either the jump zero or jump not zero conditional statement.

Lastly, there was a function for the interrupt of determining keyboard status such as if the caps lock, number lock or scroll lock is on, and if the alt key, control key or either of the two shift keys are pressed.

I asked them for an example of when the status of the two shift keys are used, and they didn't want to admit that it was fir the windows pinball game, but they all recognized it when I mentioned it.

I gave them two exercises for the day, first was to revise their first conditional program so that it would now only accept the 'y' or 'n' character instead of having one response for when the answer is 'y' and another for when the answer is not 'y'. I already gave them a sample code for this, so I just wanted to see if they knew how to insert it in an existing program.

But this is where I found out that we needed an include file to execute the display command I gave them, so I had to give them an alternative, which was a third interrupt sequence to use. But they were able to do the program.

Session 1349 has to make programs from scratch. Class dismissed.