AnsweredAssumed Answered

USB cdc virtual com port and USB otg

Question asked by Reddy.Harinadha on Sep 10, 2015
Latest reply on Sep 11, 2015 by waclawek.jan
Designing STMF405 Board. Bit confused about USB functionality. 
We need multi role USB functionality (from one usb connector). 

The current usb circuit is as shown below.
usb.png

The board should communicate with computer usb (Virtual com port) for data transfer.
Also, when the board connected to computer, it should appear simply as a usb mass storage device (like usb flash drive).

Do I need USB OTG ? As far as I know, it supports multi-role for usb.

I got confused when I saw the schematics of STM3240G-EVAL
http://www.st.com/st-web-ui/static/active/en/resource/technical/document/user_manual/DM00036746.pdf

It has two USB OTG connectors.
What is external PHY and USB OTG HS ? 
What is USB OTG FS ?

If the STM3240G-EVAL has what I'm looking for, what part of the usb I can adapt ?

Because lack of expertise, we have populated the MicroSD card socket for the board ( FAT file system). But for final product, we do not want MicroSD card.

Thank you

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