During spring of 1997, Scott Noyce and I were part of a group for the last class in the digital hardware series at Salt Lake Community College. Our final project (lab 6) for the quarter was to build a calculator using an Intel 8048 compatible microcontroller.
Our result was a fully operational 4-function calculator (2 digit). Our instructor was amazed, because we were the first (and last, as they discontinued this particular project after we finished) group to completely finish in the 3+ years that the project was assigned. The part that he found most amazing, was that we built the entire thing out of 11 ICs on a single protoboard. Quite a bit of time was spent trying to make it fit in as little hardware as possible. This led to certain assumptions which prevented it from running at a low clock speed, because of missing hardware which would have allowed signals to arrive at the correct time. From memory (it was a while ago, so my number could be off), we could not get it to run at a clock speed any less than about 70khz.
Here is an image of the calculator (as clean as we could manage on the protoboard).
Click here for a larger image
To see a large image of the project, with some added text, click here.
I would include a picture of the schematic, but I cannot find a new copy of it (the latest copy was handed in with the lab report), and I no longer have access to the program we used to create the schematics.
The only proof that I have that our calculator actually worked is a note written by our instructor. If it is a little hard to read, Here's a text version:
Scott Noyce Kevin Harris June 6, [19]97 I witnessed their final lab, a fully operational 4 function calculator, working as it should including + - / *, [signed] Rich Warnock
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Revision History:
| 25Jan2001 | Created this page. |
