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FAQ: Unable to connect to STM32H7 devices, a comment

LMI2
Lead

ST wrote a post Oct 17, 2019 which talks about STM32H7 power supplies. A link:https://community.st.com/s/article/FAQ-Unable-to-connect-to-STM32H7-devices

Especially SMPS.

There is a problem when 100pin package is used, because that package has no SMPS pins.

STM32F746 in 100pin package seems to have similar problem. Both CPUs have booting problems (external pull up on reset pin helps)

I would like to have a fix for 100pin CPUs.

3 REPLIES 3
TDK
Guru

The LQFP100 package doesn't have SMPS pins, so the SMPS should never be selected as the power supply option, and the problem should never occur.

External pullup on NRST shouldn't have any effect. It's pulled up internally.

If you feel a post has answered your question, please click "Accept as Solution".

Yes, that's what I am writing about. ST offers still SMPS as a solution.

Reset pin has a problem, that is, reset pull up does not work.

LMI2
Lead

"The LQFP100 package doesn't have SMPS pins, so the SMPS should never be selected as the power supply option, and the problem should never occur." That is clear, but 100pin packages have the same problem still. One way I could get a connection was just using a external pull up.