Free in uTasker Open Source project on GIT Hub or supported professional version.
Works on all Kinetis parts with USB (no need to port between different chips).
USB operation is simulated in Visual Studio for most powerful debugging and understanding.
Expert technical support here or at the uTasker forum (by the USB developer personally).
Industrially proven USB device operation in many products with > 10 year history of reliability.
Includes of course lots more than just USB - as well as its unique Kinetis simulator, applications that can run on almost any Kinetis part without the usual large porting effort to move; the same applications can even run on Coldfire, LPC parts with virtually no extra work involved (as well as i.MX RT parts in the near future....).