When I use STM32 recently, I need to learn more about the specific circuit parameters of F1.
So check its official data manual, and the results are recorded as follows.
Absolute maximum quota value
General working conditions
FT in the table refers to 5V withstand voltage. It can be seen in the pin definition table.
I/O port characteristics (logic level)
In the last table, you can also see that the resistance of the up/down resistors inside the STMF103 chip is 40k.