Do I have to add a pull-up resistor to the reset circuit of STM32WB55 MCU?

[Batuhan A.]

Hello,

I would like to use a reset circuit with a push-button for STM32WB55 MCU. The datasheet of the MCU gives a diagram which is uploaded to the attachment. As I understand, I use just a push-button and a capacitor. VDD and pull-up resistor is involved internally.  

But, in many example schematics which is published by ST shows that there are a pull-up resistor and VDD connection externally. And sure, the circuit is connected by an active-low signal. So, I need a VDD with a pull-up resistor.  

The question is that whether I have to use a VDD connection with a pull-up resistor in the reset circuit or not necessary. 

Thank you,

Batuhan

[YBOUV.1 · Accepted solution]

Hi @Batuhan A.​ ,

There is no need for a pull up for nreset:

please have a look on stm32wl-nucleo board:

Best Regards

[Batuhan A.]

Hi, thank you for your comment,

The second schematic image is from "STM32WB55 USB Dongle" published by ST. It was confusing me.

I had a look at the STM32WL Nucleo board schematics. I do not use the pull-up resistor.

This is the relevant part of the board for other people for a quick check.