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VBUS fireworks ( STM32F407 drawing 50ma over PA9 )

Question asked by Goebel.Vincent on Aug 18, 2015
Latest reply on Aug 21, 2015 by waclawek.jan
Hi all,

in another Thread it is mentioned and confirmed that bootloader v2.0 will configure the stm32f105/7 devices usart1 in a way that vbus detection pin pa9 will draw about 45ma. ( other thread )

I am working with a STM32F407 and experiencing more or less the same, but not just using the bootloader but whenever i configure the usb to monitor pa9. I tried this with 2 different projects, same behaviour. 
Finally i tried the discovery board, same here with the provided codeexamples. demonstration demo: ~85ma, Audio usb playback demo:~130ma, after cutting the VBUS/PA9 line: ~90ma. 

Since on 2 of my STM32F407 PA9 is now internally shorted to VCC this seems to be a rather serious issue (with 25 max allowed sinking current for io pins ).

Can anyone confirm this error? Is there any workaround ( i could configure the pin as input and monitor it myself, but would be nice to use the hardware and not mess around with the usb code )

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