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STM32 MCU pin voltage during and after reset. Entering bootloader.

Question asked by karlis77 on May 31, 2016
Latest reply on May 31, 2016 by Clive One
Hello everybody.
In my project it is necessary to reboot the MCU.
What are the pin voltages during reset and right after reset if pins before reset are configured as output with Low or High logic level? See picture below.
What about pin voltage level when it enters STM32 internal bootloader?

mcu%20pin%20volage%20on%20reset.jpg
More about my issue:
I want to enter the internal STM bootloader and to do so I must change BOOT0 pin voltage level and that is not an issue with 1 mosfet which is controlled by SBC.

To enter the bootloader I am going to do a software reset of MCU, but I am concerned about voltage level of pin which controls SBC load switch.
It would be really bad if during the MCU reset the SBC would lose its power supply.

In STM32F030CC datasheet  I found that -  During and just after reset, the alternate functions are not active and most of the I/O ports are configured in input floating mode.

Does this imply that 3.3V output will change to 0V?


Thanks in advance,
Karlis

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