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USB Device using PA9

Nico3
Senior

I want to use STM32F407V in USB device MSC mode. The device has battery to run the MCU. To fetch data from device, it will be connected to LAPTOP by USB cable.

Please confirm below configuration for schematic

1) Connect PA9 to VBUS on USB connector,  perferably by voltage divider so voltage never exceed 5V. But whats the purpose of PA9 connecting to Vbus , I am not sure..

2) Do not need any pull up on USB_DP, as MCU has internal pull up as mentioned in datasheet.

 

I hope I am not missing any point. 

 

Thanks

 

1 ACCEPTED SOLUTION

Accepted Solutions
STOne-32
ST Employee

Dear @Nico3 ,

USB specification and in particular when going to certification process - there are some checklists operations to be fulfilled.

You can refer to this Knowledge Article for more insights 

https://community.st.com/t5/stm32-mcus/management-of-vbus-sensing-for-usb-device-design/ta-p/49485

Hope it helps You !

STOne-32

View solution in original post

2 REPLIES 2
AScha.3
Principal III

1. >PA9 to VBUS on USB connector,  perferably by voltage divider so voltage never exceed 5V.

ok, its to detect the connection to a host : if lo , no host, if hi : now connected. (You dont need it, but you can use it.)

2. right , from rm :

AScha3_0-1709147331437.png

You missing something for sure .... thats real life. 🙂

 

If you feel a post has answered your question, please click "Accept as Solution".
STOne-32
ST Employee

Dear @Nico3 ,

USB specification and in particular when going to certification process - there are some checklists operations to be fulfilled.

You can refer to this Knowledge Article for more insights 

https://community.st.com/t5/stm32-mcus/management-of-vbus-sensing-for-usb-device-design/ta-p/49485

Hope it helps You !

STOne-32