AnsweredAssumed Answered

STM32F105 Shared Pin PA9 (USART1-TX and VBUS) conflict

Question asked by Reinhold on Jan 5, 2014
Latest reply on Jan 10, 2014 by Reinhold
Hello,
the STM32F105 Device share USART1-TX and VBUS for USB on Port PA9.
I need the USART1 for communication and for the internal Bootloader (only USART1 on my used 64pin Devices possible), if the firmware corrupts.
I need the USB-Device possibility for connecting the Device to a HOST-PC sometimes, but its not used for the internal Bootloader.

The other STM Devices with only USB-Device function don´t have a VBUS port und use an external resistor for USB recognition.

My question is: Can I switch off the VBUS - Port on PA9, still use the STM32F105 as a USB-Device (with external USB Resistor), and use the PA9 for the USART1-TX?

Thank you

Rheinhold

Outcomes