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STM32F427 conflict of USB and USART1

Anton Nekhoroshikh
Associate
Posted on October 06, 2017 at 11:31

Hi, everybody!

I have made the multiplexer on MCU stm32f427vit6

I want to use in him all 4 uart and 4 usart.

Also I want to use USB_OTG_FS as the VPC console of management.

But I have faced a problem if I begin to use USB, then I can't use USART1, more precisely if I accept at least 1 byte or I will send through USART1, USB right there is disconnected from the computer and connected back.

I haven't found this conflict in documentation anywhere.

All other UART and USART work without problems, data on them and are accepted and go, without influencing USB work.

Prompt what not so? What to check?

In the electric circuit there are no mistakes, there are no short circuits, PA9 and PA10 (USART1) are near PA11 and PA12 (USB), at first thought short circuit where can there, but there is no everything purely. The only thing that confuses, is that PA11 and PA12 are stated as USART1_CTS USART1_RTS, but I don't use flow control.

Prompt how to be! Thanks!

#stm32f427-usart-usb
3 REPLIES 3
Thomas Fischer
Associate II
Posted on October 06, 2017 at 11:55

try to check USB VBUS sensing,

disable it in USB configuration, it works on PA9

Posted on October 06, 2017 at 11:58

PA9 is OTG_FS_VBUS. You have to set OTG_FS_GCCFG.NOVBUSSENS.

JW

Anton Nekhoroshikh
Associate
Posted on October 06, 2017 at 12:13

I haven't noticed an elephant

Thank you

Fischer.Thomas.007

Waclawek.Jan

Fischer.Thomas.007