There is a lot of questions about this subject... Nevertheless this is not clear to me and clearly I m afraid of putting a signal at the input of a microcontroller which is higher than this supply voltage (ie 3V3). Nevertheless I would really happy if it works. So I have a microcontroller which is supplied with an LDO which converts 5V into 3V3. Nevertheless I need to use the 5V for driving "loads" thank to the microcontroller by using microcontroller outputs configured in open drain. Nevertheless when the transitor is open, the microcontroller sees 5V from the LDO. Nevertheless as I am working into a harsh environnement, I am afraid of seeing momentary the 5V to be higher than 5V. I have clearly a very bad knowledge about EMI, so I won't take any risks.
Apparently if I correctly understand the datasheet, a standard I/O ("TC") pin has a maximum voltage equal to Vddio (3V3) + 0.3 which gives 3V6. I know actually from previous projects into my firm that there were no failure due to broken microcontroller. So the voltage at the input pins never exceeds 3V6 due to the harsh environnement. When I look at the "5V tolerant pin", the margin is higher ! They are tolerant to 5V5 ! So I have not a margin of 0V3 but a margin of 0V5. So it should work ? What do you think about it ? Did I correctly understand the datasheet ?
Here is the datasheet if you are interested in : https://www.st.com/resource/en/datasheet/stm32f030f4.pdf
Thank you very much and have a nice day ! :D