.. he would, by now have composed the 8255 ouverture :)

a lot of flexibility that you didn't have before
Now you get me
What in an 8255 pin is more flexible than a '51 pin (OC, push-pull, Quasi-bidirectional, input) - Sorry, I keep talking about modern chips. Well, even what in an 8255 pin is more flexible than a steam-driven '51 pin.

it was so nice to see a post from you where you did not apply the benefits of one to the other configuration.

So can we conclude that using an 8255 in an external mmemory configuration require a slow-down as I have stated. and if a novice want to use more than 32 pins he is jumping too fast for a novice and thus do not need the 8255?

re so called "educational use" of 8255 boards (which is teaching history, not electronice) yes, the poor sods that have been suckered into paying for such a course should, of course, be helped. The important thing is that they are helped in such a form that, after graduation, they "go forth and sin no more".

not to repeat too much, please read http://www.8052.com/forum/read.phtml?id=126560 as well.

Let there be peace in the valley. Can we agree that if your teacher tell you to use the 8255, sure we will help you but ONLY with a "go forth and sin no more" caveat. If you suggest using the 8255 for an actual design you will get hammered.

Erik