Tascam Us 122, Playing mic and guitar at the same time Options

[johnnyboy]

I have been reading through posts and hear there is an issure with this. It suggests not to do this in the book, but some posts are saying this only refers to on the same side, as opposed to using, say, mic on the L and guitar on the R. Can anyone clear this up for me, I cant find out myself since I am currently using garageband which doest allow multitracking. I want to get Logic later and dont want this unit if I wont be able to do this later.