Building a Microcomputer

While looking through some pictures from college I came across two pictures that I took of the microcomputer that I built in my Physics 335 (Electric Circuits Laboratory II - Digital) class and thought I would post them for all the nerds out there!

Both images can be clicked for larger versions. This microcomputer was based around the Motorola 68000 chip (technically it is the 68008) which was originally produced in the early 1980s. I originally thought that this was the chip used in my first computer, which is sort of true, but it wasn’t the exact model… still, close enough to be cool I think! And for the really nerdy, here is the circuit diagram:

It was pretty fun to build and in the end my partner (Misty Bentz) and I built an X-Y plotter. Using the microcomputer’s two (we added an additional one) digital-to-analogue converters (DAC, the AD7569) we output our program to the X and Y inputs of an oscilloscope to produce different images. The programming was almost as difficult as building the microcomputer, well maybe not as difficult, but extremely tedious. We had to design our graphics, create coordinates, and program everything in assembly language. Once we had all the assembly language figured out we had to convert it into hexadecimal and input it into memory using the external keypad.

The entire experience was pretty cool. The end result was a star and a box and I think our initials being displayed on the oscilloscope. That really isn’t that exciting, but it was for us because we had created it all. If anyone wants to build this microcomputer, our class used the Student Manual for The Art of Electronics for all (or most?) of the labs (and while not required, The Art of Electronics would also be quite helpful for much of the background science).

Categories: Computer
  1. November 18th, 2006 at 11:17 | #1

    I’ve taken some programming courses, but never assembly… I was told it was obsolete and no longer of any real use. I quit computer programming cause it wasn’t something I enjoyed doing.

  2. November 18th, 2006 at 18:00 | #2

    Oh assembly is completely obsolete! It was ridiculous. Basically I think that “normal” programming languages create the assembly language that is sent through the processor but it is NEVER done by hand… unless you are building one yourself. ;) I have only done some basic programming, especially now in dealing with the coding of wordpress. Fortunately that is all functional when I get it and I just get to play around. I definitely have high respect for programmers, but could NEVER do it myself!!

  3. November 18th, 2006 at 18:20 | #3

    it’s because it’s base 2 binary, so if a programmer actually had to communicate with a computer using nothing but 1′s and 0′s when he was programming he would go insane. That is what all languages do… they sort of transform those 0′s and 1′s into something a programmer can manage… I worked with c and c++ for a while, i’m only somewhere in the intermediate level. I quit cause I just couldn’t see myself doing anything that draining for an extended period of time.

  4. November 20th, 2006 at 18:16 | #4

    I would have to say no thanks to all of that! HTML and PHP are about all I can handle… and at a very basic level!

  5. Kaleb Eubank
    January 19th, 2007 at 14:43 | #5

    In my microprocessors class, we’re learning assembly on the pic, then moving into a c compiler on it.

  6. thiruchelvam
    October 16th, 2010 at 06:20 | #6

    i live in japan, i am very interested in learning mc68000 assembly language programming. i can build a microcomputer.
    is it possible for you provide me the details.
    thank you.

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