Hallo Nicolas, > P0-P4 and P6-P7. P5 is not there! OOPS. Didn't noticed that. > Right. But actually both chips are overkill, they have many more > capabilities than just a single I/O port. A chip like the 6529 > would better suit the needs, but it has the big disadvantage of > not having a data direction register. The 6502->8501 design is based on my 6502->6510 design. And the 6510 has a data-direction register. (Although I wonder if it is used ever again aftre the first initialisation) AFAIK the 8501 has a DDR as well. So the 6529 won't do. Just try to design the I/O-port only using plain TTL-IC's. It is possible but you need a lot of IC's. And THAT is the reason I choose for the 6522/6526: saving space and less soldering to do. > I think both the 6526 and 6522 are good enough for testing > the concept of the adaptor during prototyping. Just curiousity: what do you have in mind to replace the port? ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| http://Ruud.C64.org Message was sent through the cbm-hackers mailing list
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