Use Qt. On Mac. Or play with it and build it youself for your system.

Copy the produced .xpl to a folder of your choise inside X-Plane/Resources/plugins/.

The SPU is a fictional device which stands between the control hardware and the X-Plane system. It contains the following functions:

• Axis - Implements a gradual change of the values of the input controller, resulting in a smoother movements of the flight surfaces of the aircraft.
• (Breaking) - Provides progressive breaking action as a custom command.
• (Tiller) - Provides a nose tiller control mode as a custom command.
• (Rudder Trim) - Provides a rudder trimming control takeover action as a custom command.
• (Protections) - Provides basic flight envelope protections.