What's wrong with 8255's
I used them till abt '95 when they were the better choice, this is why I do jnot use them any more:
1) they are made to match the x86 series and to use them with a '51 you have to jump through hoops
2) they are too slow for the moden '51 derivatives
3) with a (C)PLD you can get exatly what you need
4) just search here and see all the posts "how do I get around making my 8255 work"
5) they are antiques and will probably soon be obsolete
6) the chips from WSI do the same and more and are made for the '51 series.
7) in many cases using a chip such as the 668 (8k RAM, 64k flash inside) free up the ports and makes all pins free for I/O.

8) .. nah, this should be enough

Erik