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 second day of the third week of classes I had the three-hour session for my Interfacing Computer Systems students.

I showed them a sample of the values of four of the pins of the parallel port, which the chip controlling the port has to check first before it can send to or receive data from the external source. I also gave them the three addresses that are concerned with the parallel port.

Of course one of them is for the data to be stored in, and thus can be read from or written to.

The second is the control byte that can be set, for instance, if there is data in the data byte that can be sent to the external device. Thus, this can also be read from and written to.

The third is the status byte, which includes the bit that tells whether the external device (usually the printer) is busy reading the data byte, as well as whether it is out of paper or some such glitch. This byte can only be read from and not written to.

This time I told them that they had to make their own program for sending data to the port, using the C language.

There were several setbacks with the programs we used though. At the very least, this did not include the students forgetting all about their programming lessons though.

Some of the commands we tried to use asked for standard libraries that we did not have, and thus resulted in compiling errors.

Even when we got the program to compile correctly with the commands being accepted (outport and outportb), we still could not get the light emitting diodes (which still worked with the program I gave them) to activate.

There is a possibility that it could be because of the earlier version of the C compiler that we used.

We will have to wait until next meeting to find out though, because I blame their being mostly late at the start (some more than thirty minutes) as the reason we did not accomplish much this period.

Their Computer Circuit Fundamentals teacher, Christine, also told me that she would be using the same port for their projects and experiments in assembly language.

Session 781 is not sending output from the computer properly here. Class dismissed.