I don't know why they are, since they're generally (except for the fastest) too slow for the 12 MHz 805x.

The only reason I mentioned them was that they've come up in exactly that (trainer board) context from time to time, mostly in developing countries.

You might want to look at http://octopart.com/partsearc...ta&q=82C55 just in case you ever need one through a distributor.

I agree, for the most part, that these should be replaced by programmable logic, which is both faster and cheaper. Moreover, if you're using a fairly big part, they can be included. ISTR that Opencores has proven IP for this number.

Everybody says, "Oh, I'd never use one" and, given a choice, I'd not do so either, but if I were a student in a developing nation, and we were required as an assigned project to do something involving the thing on the trainer board they had me buy, I'd do it just to fill the reqirement.

Some for-profit institutions in the U.S. still assign work on boards with the 82C55 on 'em. I suppose that gives a clue as to the quality of the education they get at those institutions.

RE