Re: USB on a breadboard?

Thanks to you and everyone else for the help. I'm pretty sure the
first time I do this, I'm going to be doing a moderate job. But I've
got (really) good students, so I figure once they get to the class
project they will do wonderful things no matter how well I do.

Some more stuff below.

The first thing that I would like to say is that I am pleased to see
that these types of classes are being offered and I am impressed at
your initiative.
Thanks! I should have been on this a few months ago, so initiative
might not be the right word. Desperation perhaps (not really, the lab
side is actually in pretty good shape).

In response to your questions, hardware development with USB and
Ethernet may be a little bit tricky, from the breadboard perspective.
The reason being is that both technologies utilize differential
signaling on lines with controlled impedances which would be difficult
to achieve with a breadboard. I think the suggestions you received
recommending a development kit or adapter are probably the way to go.
This way you could at least focus on the concepts of the protocols and
possibly hook up a scope or something to look at the electrical
signals.

Yep, I'm aware of the signalling issues with USB (didn't know ethernet
was the same way). I was hoping that some DIP package might exist that
we could use at slow speed. But a kit will be good enough for those
that need USB/ethernet.


Second, I think that your focus on interrupt handling and uP
interfacing is very good. As an EE who was worked with embedded
systems for the 10+ years since graduation, I find that these skills
have come in handy on just about every project. Based on my experience
with a computer science person who reports to me, I think these skills
could have used some more attention in his education as they made his
eyes glaze over when he had to deal with low level issues that would
normally be handled for you by an OS. Generally speaking, his ability
to program software was excellent, but he would become befuddled when
faced with hardware interfacing. Granted, he is a CS major, but not
everybody who graduates for the program will go work for Microsoft.

The class that comes before this does a great job with most of this (on
a MPC823). I want to hit it again just to show them a different
scheme. (We probably spend a total of 30 hours of their time on
interrupts between lecture and lab, maybe more once you count in timers
and the A/D converter (both of which use interrupts).

Third, your work to interface with Linux is an excellent idea, for two
reasons. First, there is the aspect of embedded systems that focuses
on using single board computers (PCs) with a scaled down operating
system, such as micro-Linux. Second, it is sometimes possible to
obtain a development card that interfaces to a PC to do some early work
prior to the creation of the target application. As Linux allows a
user to modify the kernel, and place handlers and other types of code
in the system it makes an excellent platform for this type of
development. Windoze (spelling deliberate) isn't nearly as flexible as
with it, you are the tail and the OS is the dog.
Yeah, still not sure exactly what the lecture side will look like.
Thankfully I have a student who will be the lab instructor who has some
good ideas...


I also think that your idea about some soldering experience has merit.
I believe that being able to perform some basic board rework is a
valuable skill for both engineers and technicians. A course that
provides IPC certification takes about two days so it should be
possible to cover a fair amount of technique in a few class or lab
sessions.
IPC?
I think that introducing FPGA design is an excellent idea too. Not
only are FPGAs becoming increasing common in many designs, I believe
that being able to work with them has helped my career based on
employer comments in annual reviews.
Yeah, our students, like most new college grads (in EE/CE) know a lot
about FPGAs. Or at least how to use them...


You may want to consider introducing some of the aspects of real time
design and programming. Real time issues are inherent to some degree
in just about every embedded system. In contrast, though, in most PC
based applications, the user has little control over the timing. I
think uCOS-II might be an excellent avenue to pursue this.

Agreed. Not sure I'll get to something this semester, but...


Other areas to consider discussing would be the importance of system
reliability and how this is achieved through the use of watchdog
circuits and proper coding practices. Also you may want to discuss the
importance of good user interface design and how often times the
designers think very differently from those who use the systems.


The only other thing I can think of that would be helpfull, that you
didn't explicitly mention is some experience with development tools
like how to properly use oscilloscopes and logic analyzers and most
importantly, understanding their limitiations.

Using is easy. Understanding what they are seeing (ie the limitations)
is more difficult.

Great! Thanks for the thoughts. I'm certain only a bit of this will
make it into the class, but maybe more next time...

Mark

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Relevant Pages

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