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YOSHI2
Associate
August 1, 2024
Solved

Regarding the STM32WB5MMG's pins (PC5, PB10, and PB11).

  • August 1, 2024
  • 2 replies
  • 1130 views

I am trying to develop a product using the STM32WB5MMG.
In the schematic 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.

Best answer by STTwo-32

Hello @YOSHI2 

Those 3 pins are sensitive pins. You can use them as gpios for sure. All you have to do is to add a 3.3 pF capacitor in a small package such as the 0201 or smaller as close as possible to the output of the pin. You have also to position a continuous ground plane adjacent to the GPIO (General Purpose Input/Output) signal tracks on your PCB layout.

Best Regards.

STTwo-32 

2 replies

Peter BENSCH
Peter BENSCH
ST Technical Moderator
August 1, 2024

Well, these three pins are particularly sensitive pins, which is also described in the data sheet, section 6.2.4:

When PB10, PB11 and/or PC5 are used, a 3.3 pF capacitor in a small package such as the 0201 or smaller, must be placed as close as possible to the output pin. Also border the GPIO tracks with the ground plane.

Yes, of course you can use them to control remote keys.

Hope that helps?

Regards
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
    STTwo-32
    STTwo-32Best answer
    ST Technical Moderator
    August 1, 2024

    Hello @YOSHI2 

    Those 3 pins are sensitive pins. You can use them as gpios for sure. All you have to do is to add a 3.3 pF capacitor in a small package such as the 0201 or smaller as close as possible to the output of the pin. You have also to position a continuous ground plane adjacent to the GPIO (General Purpose Input/Output) signal tracks on your PCB layout.

    Best Regards.

    STTwo-32 

    To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
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