It seems that every time a query of this sort comes up, everybody tells him what OTHER hardware to use, rather than telling him how he might encourage what he wants to use to work.

Now, I don't know why he wants to make the hardware he's chosen work as he wants, but he's the one who's chosen it.

There is NO indication in ANY of the posts as to whether the choice of the antique is due to relying on a book or "teacher" mired in the past.

As to helipng him with making the thingy work, there are several suggestions above and (hopefully) all with the advise "do not do this again"

There is one enormous difference between letting a novice believe that using the antique is the right choice by "simply helping" and "helping with a warning". A simple "this is how to interface with an 8255 can very easily give a novice the iompression that it is current practice.

Yes, I have not participated re how to make 8255 work, I have fortunately forgotten all about it although I used the device quite extensively in the days when the king of diamonds were still just a jack.


Erik