The Davis Square Community

I've been wondering recently: as a pedestrian traversing Powderhouse Circle, am I allowed to cross at the crosswalks at any time (which is what I've been doing, assuming there isn't a car with an oblivious driver barreling towards me), or am I supposed to hit the walk button and wait for the walk sign (which turns the entire circle into a 6-way red light)? I kind of hate doing the latter unless traffic is really heavy and I need to cross the diameter of the circle, but I wonder if I'm technically jaywalking if I cross without hitting the button.