How to handle unused pins on STM32WB5MMG

[YOSHI2]

(1)
I am trying to develop a product using the STM32WB5MMG.
Can I leave the unused IO pins of the STM32WB5MMG as NC?
Do I need to do pull-down (or pull-up) in HW?

The STM32WB5MMG has a lot of IO pins.
If I need to place a pull-down resistor, I'll have to place dozens of resistors.
That doesn't seem realistic.

 

(2)

Are you able to provide an internal schematics of the STM32WB5MMG?
If so, please provide a link.

[STTwo-32]

Hello @YOSHI2 and welcome to the ST Community :smiling_face_with_smiling_eyes:.

• For unused GPIO pins, it is generally recommended to set them to analog input mode. This configuration minimizes power consumption and avoids floating states.
• For such a purpose, please contact our Sales and Marketing teams.

Best Regards.

STTwo-32

 

[YOSHI2]

Thank you for your reply.
You advised me that I can avoid floating state by putting unused IO pins into analog input mode.
Is my understanding correct that when put into analog input mode, pull-down resistors are not required and the pins can be left in NC?

I have an additional question.
In the circuit diagram of STM32WB5MMG, the pins PC5, PB10 and PB11 are connected to GND via 3.3pF (C7, C8, C9).
Why are these pins connected to GND via 3.3pF (C7, C8, C9)?
Does this mean that PC5, PB10 and PB11 cannot be used as IO pins?
I want to assign PC5, PB10, and PB11 to remote control keys.

[STTwo-32]

Hello @YOSHI2 

For the Pull-down resistors, I don't think it is necessary, but I suggest you test it (it may help but not a tested solution). 

For the second part of the question, could you please ask it on a new question after selecting a best answer on this one. This behavior will help our Community Customers that have the same case. Please make sure to add more details (with schematics and all).

Best Regards.

STTwo-32