Hit by pitch

If a batter accidentally steps on home plate in an effort to avoid an oncoming pitch, will he still be called out?

Depends upon where the pitch is. If the pitch is in the strike zone, then it’s a strike. If it isn’t, then it’s “Take your base”. This is presuming also that the batter isn’t stepping on home plate in an effort to impede the catcher from making a throw to another base. But let’s say the pitcher throws a pitch at the batter’s head and he hits the dirt and his feet end up on the plate and the ball hits his helmet. That’s an HBP in my book.