Dear All,
I'm having problem to get DFU over USB running on custom board.
In general device can boot from SD card and with no SD card it can be detected via uart4 by STM programmer, so it enters DFU as far as I can tell.
USB DP/DM is connected to DP2 (being pulled-up to ~3.3V) and DM2 (looks like a weak pull down). OTG_ID (PA10) hangs free and OTG_VBUS (U15) hangs free.
3V3_USBHF+FS connected to LDO4 and present (3.3V)
EDIT: 24Mhz xtal present, no 22Ohm series resistors and also removed all esd protection at this moment...
Nothing happens on the USB lines when I connect the cable to the PC and the device is not detected. The voltage on the OTG_ID pin is LOW - which is strange, as is should be pulled up theoretically. Connecting OTG_VBUS (PA10) pin to VBUS from the connector does not change anything, that is - no detection, no communication, looks like my device behaves like a host.
I could not find any reference design for USB connection, but I really thought it is so simple. Any suggestions what else I could check?
Thanks
