Hi All
I have been involved with USB Device projects on a large number of Kinetis KL, KV and K parts. During this time there have been ocassions when the USB device hasn't worked immediately - either due to a SW setting or HW problem - and the following is a list of things to consider when this is the case.
Point 1 is the most criticial for new HW since I have experienced several prototypes that didn't work until corrected!
Otherwise the USB device driver is compatible between all parts as long as the following settings don't have any deviations.
1 - HW must have correct USB regulator design (check the recommendations in the corresponding user manual and follow them accordingly)
2 - USB clock must be correct - 48.000MHz - and the minimum system/core clock of 20MHz be respected
3 - The USB bus master must be given rights to access Flash so that the descriptors can be taken directly from const memory (flash). Check FMC_PFAPR (not applicable to KL parts)
4 - The USB OTG interrupt vector ID must be correct
5 - If the chip has MPU concurrent access to MPU controller must be allowed. Check MPU_CESR on parts with a memory protection unit.
This list is believed to be complete since no other problems have ever been encountered.
Regards
Mark
