STM32H725 USB FS PHY not detected

[fing]

Hello,

I have been working on a project that requires USB communication with an STM32 MCU. Unfortunately, the computer cannot recognize the device.

On the hardware side, I am using the STM32H725VGT6 mcu, an isolator, and a USB-C connector with some ESD protection. 

 

On the software side, I am using the internal FS PHY with the following settings.

I think there might be some sort of hardware issue. On the mcu side D+ is only pulled to 2.6 V and it doesn't change state on connection. Windows couldn't even detect the device. What could cause this problem?

  

[fing]

After resoldering every pin D+, D- on the high and low side, it is working properly. If you are not using 48 MHz for the clock, Windows won't recognize the device descriptor, so in my case I used the HSI 48 MHz in the MUX. USB is now working correctly.