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Associate II
February 15, 2026
Question

PC connection to STM32L432 for data communication

  • February 15, 2026
  • 3 replies
  • 221 views

Hello everyone,


I have a Python app that needs to communicate with my custom STM32L432KC board. Before ordering my prototype board, I was wondering if it is possible to do it only via USB with the pins PA11 and PA12, or if I need a USB‑UART chip like the CP2101‑GM?

 

Thanks

3 replies

mƎALLEm
Technical Moderator
February 15, 2026

Hello,

And what is the relation of ST-LINK in the thread's title with your question?

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Associate II
February 15, 2026

Actually, I'm wondering if I need an ST-Link or if the CP2101-GM chip will be able to communicate via UART without it. So, do I need an ST-Link to see the STM32 in the COM port on Windows, or will the CP2101-GM chip work as well? And is the chip necessary, or can I have a COM port with just the STM32 chip?

mƎALLEm
Technical Moderator
February 15, 2026

Ok but the tilte needs te be updated to more concise.

Which ST-link you are referring to? a stand alone ST-LINK like this one:?

mALLEm_2-1771189781418.png

 

Or an ST-LINK that you've de-attached from a Nucleo board?

mALLEm_1-1771189605344.png

For the second one yes you can do it. For the first one, not possible.

Meanwhule, you can use any USB to UART bridge to connect your PC/USB to STM32/U(S)ART.

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Andrew Neil
Super User
February 16, 2026

@Raphael716 wrote:

was wondering if it is possible to do it only via USB with the pins PA11 and PA12


Yes, the STM32L432KC has USB on pins PA11 and PA12:

AndrewNeil_0-1771235605489.png

https://www.st.com/resource/en/datasheet/stm32l432kc.pdf#page=53

via: https://www.st.com/en/microcontrollers-microprocessors/stm32l432kc.html#documentation

 

That will mean that you will have to do a complete USB hardware design on your custom board, and provide a complete USB software implementation in your custom software.

 

Depending on your level of both hardware & software experience, you may find it easier to just use a USB-to-UART  adaptor...

(avoiding the complexities of USB hardware & software implementation is exactly why USB-to-UART adaptors exist)

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.