The replies are great!! Just be aware that every HR department is different and you could have very different outcomes.
Just be prepared. 
One thing I would say, is to make certain that you are doing all that is right. You won't be perfect but when you look at the policies etc, sometimes you might be surprised about the areas you might need to brush up.
Doing this will also remove evidence that your manager can use as justification for his behavior.
Then do everything everyone else has said. But do start looking for another position AND securing people who can give you a good reference other than this turd.
You will be surprised as to how relieved you will feel by having a few resumes out to recruiters. Good luck!!
