I am trying to program an STM32F7 series MCU on a custom PCB (migrating over from a nucleo dev board) but I am having trouble connecting to the MCU. Using STM32CubeProgrammer (the new programming software) I get the error "DEV_NO_DEVICE" and the logfile reads:

12:45:54 : ST-LINK Firmware version : V2J29S7
12:45:54 : Error: ST-LINK error (DEV_NO_DEVICE)

The GUI reports that my target voltage is 3.22V and I have 'connect under reset', 'hardware reset' and 'SWD' selected on the options panel.

Interestingly, I can update the firmware of the board by launching the update window with the STLINK-V2 unplugged, replugging it with the window open and then beginning the update. Beginning the update procedure with the board plugged in results in the error "ST-LINK is not in the DFU mode. Please restart it". The first time I updated, I was able to connect to the chip (I didn't program anything at the time), but not since.

EDIT: Thanks for the answers/suggestions. My spare ST-Link V2 adapter arrived today and trying my luck with that actually solved the problem! Must have been a bad adapter.


1 Answer 1


I think that you mess two things. One is update of ST-Link firmware, the second one is programming the target micro.

The message shows that your target uC does not respond and the question why is very difficult. You need to connect all the VDD and VDDA to the power supply with the proper capacitors. All the grounds have to be connected as well. Check if you do not have any short circuits on your board. Check with the multimeter if you have not mistaken any connections.

There is no simple solutions - you need to check your board, connections, paths, joints - check if you do net have any hidden bridges etc etc

I would suggest to use the old st-link utility instead.

  • \$\begingroup\$ Didn't he say :" I can update the firmware of the board by launching the update window with the STLINK-V2 unplugged " ? \$\endgroup\$
    – Long Pham
    Commented May 10, 2018 at 12:58
  • \$\begingroup\$ @LongPham And what does it mean? And how ? Magic? probably the glitch in this software. \$\endgroup\$ Commented May 10, 2018 at 13:30
  • \$\begingroup\$ @LongPham - that appears to be about updating the firmware of the programmer, not the target. In particular the mention of DFU would only apply to something connected via USB (such as the programmer) and not to a target connected to a programmer via SWD/JTAG. \$\endgroup\$ Commented May 10, 2018 at 14:38
  • \$\begingroup\$ @PeterJ_01 Your suggestion might be a possibility. As he was able to interface with the chip, that possibility is (I think) negligible. I would suggest him to examine the ST-link instead (make me remember my legit ST-link) and check JTAG/ SWD/ Debug setting also. +1 for your answer. \$\endgroup\$
    – Long Pham
    Commented May 10, 2018 at 15:05
  • \$\begingroup\$ @PeterJ_01 Thanks for the answer. Swapping the ST-Link adapter did actually solve the problem. Lesson to be learned: always use a genuine ST-Link programmer, not the cheap eBay versions! \$\endgroup\$
    – JB515
    Commented May 11, 2018 at 13:12

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