Controlling multistability, i.e., designing control laws for switching among different attractors, is an emerging issue in the area of memristor circuits. The paper considers the Chua\'s memristor circuit which is known to display infinitely many attractors, each one contained in an invariant manifold of the circuit state space. The problem of switching among these attractors via pulse-programmed feedforward control laws, which are implementable via a unique current/voltage source, is investigated. In particular, it is shown that if the shape of the voltage source in series to the inductor is suitably designed, then it is possible to switch in finite time from one attractor to another.