Skip to main content
Graduate
March 6, 2025
Solved

Clarification on Crystal Oscillators in STM32L432KCU6

  • March 6, 2025
  • 2 replies
  • 899 views

Hello,

I am working with the STM32L432KCU6 microcontroller and noticed that it includes a 32.768 kHz crystal. I would like to confirm whether there is a separate crystal for high-speed operation or if an external high-speed crystal needs to be added. Could someone clarify this for me? Any insights would be greatly appreciated.

Thank you!

Nikunj

    This topic has been closed for replies.
    Best answer by mƎALLEm

    Checking The datasheet of STM32L432KCU6. It's a UFQFPN32 package.

    LSE is using PC14 and PC15

    HSE is using only PA0 and that case you need to use a crystal oscillator (XO)

    mALLEm_0-1741263390209.png


    @Nikunj_17 wrote:

    Does this controller support an HSE crystal? Also, what is the actual function of PA0?


    No. Its doesn't support a Crystal for HSE but a Crystal oscillator (XO) as described in this link. XO has only one input that needs to be connected to PA0/CK_IN pin of the MCU.

    Hope that helps.

     

     

    2 replies

    Graduate II
    March 6, 2025

    LSI is not a crystal.

    MCU will start off MSI or HSI. Check Datasheet and Reference Manual.

    Nikunj_17Author
    Graduate
    March 6, 2025

    Thanks for your answer!
    Does this controller support an HSE crystal? Also, what is the actual function of PA0?

    mƎALLEmAnswer
    Technical Moderator
    March 6, 2025

    Checking The datasheet of STM32L432KCU6. It's a UFQFPN32 package.

    LSE is using PC14 and PC15

    HSE is using only PA0 and that case you need to use a crystal oscillator (XO)

    mALLEm_0-1741263390209.png


    @Nikunj_17 wrote:

    Does this controller support an HSE crystal? Also, what is the actual function of PA0?


    No. Its doesn't support a Crystal for HSE but a Crystal oscillator (XO) as described in this link. XO has only one input that needs to be connected to PA0/CK_IN pin of the MCU.

    Hope that helps.

     

     

    Technical Moderator
    March 6, 2025

    Hello,


    @Nikunj_17 wrote:

    I am working with the STM32L432KCU6 microcontroller and noticed that it includes a 32.768 kHz crystal.


    There is no MCU in this world embedding a crystal. The crystal needs to be added externally.

    May be you are talking about a board? if that case, which board? 

    In case you need to add two crystals for LSE and HSE on your board.. yes they are separated.

    PS: you said crystal oscillator but you need to know there are differences between Crystal (XTAL) and Crystal oscillator (XO). See this link.