Needless to say, if age is what you choose as the determining factor, you and I are both older than the 8255. I'm not offended at being seen as "old" but I doubt many people consider me or people like me as obsolete. The wheel is certainly older than I, yet it's not obsolete. Of course, if you pick and choose your definitions from among the range ...

I believe that as long as there are people asking questions about a device, e.g. the i8255, since those items are on many development boards for the i805x, they should be treated with respect and their questions answered. Your bent, and that of some others, to shirk their responsibility to address the question before them by calling the question wrong-headed because you don't like the device, is not helpful.

One comment you made (I think that was you), indicating that the 8255 was designed for the 8031 with no internal memory ... is completely wrong. It was in full production before anybody even thought of the 805x. The chips designed for the 8085/86, and 804x/5x, with their multiplexed address/data bus, were the 8155 and 8156. Those appear in many of the app-notes and handbooks of the time. Of course, for "larger" systems using these single-chip-microcomputers, the 8255 appeared with astonishing regularity. I think this is because of their adaptability to such a wide range of applications and popularity. Now, the things don't drive much, so if you need to drive a relay, you need a transistor, but, the same is true of the I/O on most single-chippers from any source.

RE