Andy said:
but the 8255 is an old crock that's been obsolete for years!

This isn't true! Production of 82C55 is still active. Have a look at here:

http://www.intersil.com/cda/devic...55A,0.html

Even a radiation hard variant is manufactured.
Whatever Andy said, the following is the fact: "but the 8255 is an old crock, the use of which in new designs, has been obsolete for years"

Even a radiation hard variant is manufactured.
Radiation hardened devices typically lag "normal" technology by ages.


Andy said:
The only real reason that the 8255 was ever used was for old-fashioned 8031s with external memory - because the address+data bus used up nearly all the port pins.
This isn't true either. 8255 was and is widestly used in most different electronics applications! Why else should intersil manufacture this chip today??
Andy refer to '51 applications, you, Kai refer to "electronics applications" that will definiely give different numbers.

Erik