We're near completion of a project using a K20 with USB. There appears to be an issue with with the USB hardware failing after repeated use. It basically will become undetectable, i.e. the reset command is never send from the computer.
We followed the component layout example provided by Freescale.
The problem seems to occur when a USB cable is connected to the USB port and we reprogram the board. Is this a known issue? Or could there be any other known potential cause of the USB port to become completely unresponsive?
This has happened on 3 - 5 boards so far.