Is it possible for a motor to perform only half a rotation?

Hi! Does anyone know how to get a motor to rotate with only half a rotation in Creo Parametric 3.0? I had tried applying constraints such that the rotating part could only perform half a rotation but anytime I tried applying a servo motor to run mechanism analysis, it would give an error message saying "Assembly failed. Constraints could not be satisfied". Is there any way at all that I can achieve half a rotation with a motor at a specific angular velocity?