Don't call or txt him at all. By not calling or txting it'll make him start to wonder why you stopped, so he'll be forced to call / txt you out of curiosity.
I did this after my ex-girlfriend broke up with me. I didn't call / txt her for 3+ days, and by day 7...she called me and was wondering why I haven't talked to her in so long.
You have to show that he isn't the center of your world, and you have better things to do then to just sit around and wait for him to call / txt you. It'll either drive him nuts that you haven't talked to him and he'll contact you, or things just weren't meant to be.
Hope this helps...