Nice to hear you again. Since I want to extend interrupt sources and only want use one 8051, but the 8259 is one of my choices. Do you have any suggestions? Best regards.
"I'd like to know what is the reason to stay away from 82xx chips." Did you want just the 5-minute list, or the full half hour...? ;-) http://www.8052.com/forum/read.phtml?id=81257 If you really want to use an obsolete chip, you could at least use a modern one - and choose a Triscend E5! Anyhow, there are plenty of 8051s available today with tons of IO built-in. So why would you choose a variant with insufficient IO and then add an inappropriate, obsolete part to increase it to the required IO?! Makes no sense! You'll be telling us you've found this box of thermionic valves ("tubes") next, and how can you interface them to an 8051...
an added comment The main reason that you still see 82xx in use is that many authors of "reference designs" or "demo boards" are simply too lazy to redesign their antique stuff. Selling a thing you made 10 or more years ago, is pure profit, making a contemporary design require effort. Erik