How can I make my own microcontroller?

Question

How can I make my own microcontroller? I\'ve done some work using GAL chips and programmed a chip to do simple commands such as add, load, move, xor, and output, but I\'d like t

Answer 1

I saw a textbook once that stepped through building a machine from TTL chips. This had the same instruction set as a PDP-8, which is very - and I mean very - simple, so the actual machine architecture is easy to implement in this way.

The PDP-8 FAQ mentions a book: "The Art of Digital Design," second edition, by Franklin Prosser and David Winkel (Prentice-Hall, 1987, ISBN 0-13-046780-4). It also mentions people implementing it in FPGA's.

Given the extreme simplicity of this CPU architecture and availability of PDP-8 code or reference implementations it might be a good starting point to warm up with.

Alternatively, an acquaintance of mine implemented a thumb (cut down ARM) on a FPGA as a university project run by one Steve Furber (a prominent Acorn alumnus). Given that this could be compressed into a format small enough for a university project it might also be a good start.