I don't remember your original post, so it may well have been a little verbose :) I may be missing something here but I have used the interrupt on change for a software UART without any problems... prehaps Andy was just suggesting one good use for the feature ? Regards, Simon -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics