We are running a third party USB stack on our MK22FN Kinetis processor, and we are considering trying out the Freescale USB stack v4.1.1 since we have some problems with the third party stack.
But it is unclear to me whether the Freescale stack supports our target. Only K20 and K21 are listed among the development boards. But then, I would expect the USB block to be similar enough to be able to use this stack.
Happy for any feedback!