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OskarM
Visitor II
September 17, 2025
Solved

stm32mp15x dfu over usb not detected

  • September 17, 2025
  • 1 reply
  • 723 views

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

 

    This topic has been closed for replies.
    Best answer by OskarM

    There is no magic in electronics. After another few hours and soldering down to the PCB directly it worked. It seems the connector was damaged/worn out and worked only occasionally, so it was very hard to catch when it didn't.

    1 reply

    O
    OskarMAuthorAnswer
    Visitor II
    September 18, 2025

    There is no magic in electronics. After another few hours and soldering down to the PCB directly it worked. It seems the connector was damaged/worn out and worked only occasionally, so it was very hard to catch when it didn't.

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