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Visitor II
January 20, 2025
Question

STM32F427 PB14 conflict with internal USB PHY

  • January 20, 2025
  • 1 reply
  • 555 views

Hi I am having the same problem as described in the old post down below.... is there a way to activate the link inside to see the fix? 

I am also using the external ULPI PHY, but when the USBD_Connect function executes, pin PB14 is lost. This is becasue the USBD_Connect function is enabling the internal PHY. I know there is a way to fix this but do not remember how. I needed to reinstall the whole environment so the fix was lost and now the code does not work since I need pin PB14 as a GPIO.

Here the post I am referring to:

https://community.st.com/t5/stm32-mcus-products/stm32f4xx-spi2-and-usb-hs-conflict/td-p/438246

Regards

 

Mark

    This topic has been closed for replies.

    1 reply

    Technical Moderator
    February 12, 2025

    Hi @MBurg 

    It is pointing to this thread

    https://community.st.com/t5/stm32-mcus-products/stm32f4-i2s2-pin-af-multiplexer-issue-s/m-p/465934

    If OTG_HS_GCCFG_PWRDWN is set (transceiver power down is deactivated) the DM/DP pins are driven by USB.

    FBL_1-1739354545219.png

    OTG_HS_GCCFG_PWRDWN is necessary to be set only when using the HS instance.