Interrupts with CMUCam

[RyanW]

For our robot, we want to use a quadrature encoder so that we can move our manipulator to preset heights on the arm. I read the "Quadratuer Encoders" white paper, and modified the example code to work with one interrupt.
This works fine with the default code, but I noticed that on Kevin's CMUCam code, the use of serial_ports means that user_Serialdrv.c and user_Serialdrv.h must be deleted. Where, then, do I put the interrupt code, and how do I hook the encoder up to the robot controller? I read through serial_ports.c, but I didn't really see a place for an interrupt handler where I could add the encoder code...