Project 1: Computer design

In this project you'll design a simple but complete computer processor. You will build your processor in a program.

This project proceeds by building up pieces until we finally get to a processor. A PDF document describes all the pieces to this project. (The assignment comes directly from a second-semester CMU computer science course titled `Great Theoretical Ideas' (15-251).)

Instead of drawing your processor on paper, you should use the freeware software package Digital Works. This program is nice, but it's not entirely intuitive. Be sure to look at the on-line help (which I found very useful), and contact a TA as you begin making your circuits to make sure you're doing it right.

Some changes from what appears in the project handout:

• You'll notice that Digital Works includes several components that the project asks you to build (an AND gate, for example). Do not use the relevant component built into Digital Works until after you have implemented the gate. For example, until you define an AND gate, you may use one; but once you define it, you may use an AND gate as you wish.
• Problem 2: Your one-bit adder (which takes three one-bit inputs to add) should use at most 5 logic gates. (Digital Works includes an adder that requires more gates; don't use it.)

• Problem 6: The project refers to clocked-not gates, which Digital Works does not include. Instead, let me give you the solution to Problem 6a, which you should use in Problem 6b.

  One tempting approach to Problem 6b is to attempt to add more gates to the clock. Don't do this. Your only use of the clock should be exactly as illustrated above.

• Problem 7: You needn't use Digital Works for this huge circuit; hand-drawn circuits are fine here.

What to hand in: You will not hand this in electronically. Instead, hand in a printout of the circuits that you make. Be sure to keep an electronic copy too.

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