If the O/P doesn't say that he's driving something with P0, what it is, and what its requirements are, there's no reason to believe, regardless of what he asks, that he needs pullups on P0. Who knows what he's doing? He may be taking an input and counting it, then sending the count out when requested, via the UART. He may not use any outputs at all. He doesn't say ...

There are so many people willing to spout "rules" that have no relevance to the situation, that it confuses people who are starting out. Newbies are bombarded with "use this" and not "figure out what you need and then use that." Most of the time, they're wrong. For all we know, he read one of those, one that says you must use a 10K pullup on P0, and has no idea why one would want to do that.

RE