We are planning to use TWR_SER2 and K60F120M boards for HS USB CDC device mode and later on use these boards as the baseline to come up with our own custom board for USB HS CDC. Schematics for both boards are attached.
High level questions from these 2 boards to help getting my mind straight
1- USB Host receptor J6 only acts as host in full speed mode? Can you please confirm? It connected K60 USB_DM/DP pins to J6 D+/D- pins and use K60 GPIO4 (PTB8) to drive the MIC2026 ENB to drive OUTB (USB_VBUS_HST) to J6 VBUS pin as well as K60 VREGIN through elevator. Now, the K60F120M showed PTB8 is mapped to both location of B35 and A63 of the elevator interface J7A. Is there a mistake? Both B35 and A63 have different functionalities on the SER2 board. Please take a look at the attached schematics.
2- The SER2 schematic is designed to support OTG on J18. For J18 USB mini receptor acting as USB HS CDC device only, do we need to feed the VREGIN with the VBUS signal like in the FS device CDC case? For OTG J18 receptor, my understanding is that the USB3300 supposed to handle and behave as host or device and only communicate back/forth to the K60 via UPLI signals w/o the need to feed voltage to VREGIN of K60 device? How does the K60 firmware knows that the interface is the HS or FS? It seems that this information has to be sent from USB3300 to K60 devices? If someone has an apps note on this USB3300 and K60 communication, etc that would be greatly appreciated.
3- I have asked about the USB HS device CDC stack support for K60F120M device on forum and it seems that there is no support yet. My understanding is that all the Kinetis family should have very similar USB IP hardware. My question to NXP support team is which Kinetis device (or Kinetis eval board) which has USB HS stack supported by NXP (example / demo codes) that I can purchase to check out the USB HS device CDC with TWR_SER2. If they are almost the same, I can "try" port it from the supported Kinetis device back to K60F120M. I don’t think we can make the USB HS firmware by ourselves on K60F120M. Can you please advise?