STM32H725 SMPS issue

[BenUtzer]

I am having and issue with a STM32H725RGV6.

After powering my board, I can see the SMPS output at 1.36V, which I have connected to the VCAP inputs.
I can also connect to the µC using the STM32CubeProgrammer.

However, after flashing a simple firmware, the SMSP output drops to 0V and I can not connect anymore. I am aware that this can be the result of an improper SMPS configuration (https://community.st.com/t5/stm32-mcus/unable-to-connect-to-stm32h7-devices/ta-p/49296). However, in my (cube generated) project am am calling

HAL_PWREx_ConfigSupply(PWR_DIRECT_SMPS_SUPPLY)

so this should be correct. Additionally, I tried to upload a program with nothing but an infinite loop in main, and the problem still occurs.

When pulling BOOT0 high, the SMSP output becomes 1.36V again and I can connect again. This makes me believe, that everything is set-up correctly hardware-wise. Otherwise, the bootloader would not run. 

thank you for your help

[SofLit · Accepted solution]

Hello @BenUtzer and welcome to the community,

If you are using CubeMx to generate the code, I think you have the same issue as these threads:

Thread1

Thread2

Please confirm.

[BenUtzer]

Thank you very much. I can confirm that this was indeed the issue.