I have been having a problem with my STM32H725IGT custom PCB, because I can't flash it even though i tried almost everything. I have tried flashing from nucleo's programmer and from stlink-v2 clones via SWD connection, but none of the STM32Cube programs detect my device.

What i have tried:

+I checked if all of the pins have power and if all of the ground pins are well connected.

+I have checked the voltage on VCAP which is 1.6V so something is working inside I guess.

+I have checked if I didn't mix up header pins and if headers pin have continuity to SWD pins on MCU.

+I have tried setting boot0 to high but it didn't change anything.

Would flashing via I2C be possible in this case ? EDIT: Schematic picturepower supply and boot

  • \$\begingroup\$ try adding a schematic snippet to clearly show you design and connections to the programmer \$\endgroup\$ Dec 3, 2023 at 2:28
  • 1
    \$\begingroup\$ Vcore usually isn't so high. There is no way to know what the problem is without the schematics. Do you even power it via internal LDO, internal SMPS, or via other mechanisms? \$\endgroup\$
    – Justme
    Dec 3, 2023 at 2:53
  • \$\begingroup\$ Vcap should be between 1 V and 1.35 V. \$\endgroup\$
    – Antonio51
    Dec 3, 2023 at 10:02
  • \$\begingroup\$ I added schematic picture. I'm also powering from external LDO. I accidentally powered it from 5V for short amount of time, maybe that killed it ? \$\endgroup\$
    – Synte
    Dec 3, 2023 at 11:11

2 Answers 2


If you powered an IC with absolute maximum rating of 4.0 V even momentarily from 5V supply, the IC and all other ICs on the board that can't handle 5V are burnt.


Would flashing via I2C be possible in this case ?

You should read the note

enter image description here

The table 2 gives :

enter image description here

Table 111 gives :

enter image description here

And in particular ...

enter image description here

  • \$\begingroup\$ The OP writes about wanting to use SWD - which does not depends on a bootloader. \$\endgroup\$
    – brhans
    Dec 3, 2023 at 14:30
  • \$\begingroup\$ @brhans >>> Would flashing via I2C be possible in this case ? <<< \$\endgroup\$
    – Antonio51
    Dec 4, 2023 at 7:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.