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Does anyone know how I can detect if my USB device is connected to a Host or not?
Thx Steven
A little feedback from my side: I used the same design with the same diode as the eval board and after I changed the ESD diode to an other with a additional diode on Vusb and voila it works because the problem was that the USB D+ was keept high from the STM32f and was feeding its own detection line PA9.
Thx all for your help and hints
Can you perhaps write in details (regarding board schematic found here http://www.keil.com/mcbstm32f200/mcbstm32f200-schematics.pdf) what needs to be changed on Keil MCBSTM32F400 board so other people having same problem can do it themselves.
sure! IC8 in the schematic is an USBLC6-4 use a WE-TVS instead. As you can see on the datasheet(katalog.we-online.de/.../824014.pdf) they have an extra diode on pin 5 in reverse direction to VDD. If now D+ is high on IC8 pin 3 it doesn't feed back to VBUS_FS which is connected to the USB detection pin PA9.
Cheers!
Great, thanks for detailed explanation I hope somebody having same issue in future will value this :-)
So with mentioned hardware changes + adding definition USBD_VBUS_DETECT=1 for driver solves problem of connect/disconnect detection.