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STM32L4P5 PB9 pin states in reset

Associate III

Why does PB9 idle high in reset for the STM32L4P5?  At least I'd like to know this the next time I design a board, where I could find this reference.  Full part is STM32L4P5RET although I'm guessing its the same across multiple parts.


PB3 / PB4 based on default GPIO MODER RM0432

Perhaps CAN1_TX PB9 involvement per AN2606 in the Boot Loader, not if your code runs.

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On what hardware do you see this?

How do you make sure the mcu is in reset?

How do you observe the pin in question?