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.
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