We currently have the KL25Z128 connected to a usb port (as shown in the attached diagram). We regularly have failures with this peripheral (the USB module only - the rest of the chip functions correctly) which require a replacement of the chip - the worst being the PC doesn't even recognise that a device is connected, the best is it being recognised and enumerated (with a driver install request) but then get a "this device has malfunctioned" message when connecting to the port in Windows.
We are using a CDC driver module in Processor Expert. After replacing the chip, for a period of time the USB module works correctly and we can talk to the chip as a virtual com port and then it will begin to fail again. Our guess is that the silicon on the KL25 itself is somehow being damaged by the USB connection although we are not sure how.
Any help or advice would be appreciated.