Setting Up STM32L452 as USB CDC Device with VBUS-Sense

[TFels.1]

I'm working on a setup with a STM32L452RE and want to use the USB as a CDC-Device. I want to use the internal PullUp for D+ and the VBUS-sensing. I only find very unspecific Information about what i got to do in software.

Also which Pin to use (probably PA9) but i don't find any information about this in the reference manual or other documentation for the STM32L452.

[gbm]

See the datasheet, AF tables. Still, I can't see too many reasons for VBUS sensing. If you turn on VBUS sensing in CubeMX, it will assign a proper pin for it automatically.

[TFels.1]

In the AF-Tabels in datasheet i can not find any info for VBUS-Sensing. Wheter at Port PA9 nor any other.

I can not find any configruations for VBUS sensing in CubeMX. I'm using CubeMX inside CudeIDE. Where to find this settings?

 

[Amel NASRI]

Hi @TFels.1​ ,

Please refer to the 2 following resources:

• Community article: Management of VBUS sensing for USB device design
• Application note AN4879: USB hardware and PCB guidelines using STM32 MCUs

Was suggested content helpful? If not, please let me know if you don't find the answer to your request and tell me what is missing.

-Amel

[TFels.1]

Hi,

is it correct that i only need to connect the PIN PA9 to the voltagedivider mentioned in the AN 4879 and i'm done? Nothing else to configure but PA9 as Input?

That would be really simple.