STM32F407-Disc1: UART1 on PA10+PA9 does not work

[chkolli]

My company has purchased STM32F407G-Disc 1 board for evaluation in order to use STM32F407VE in our hardware.

UART6 (PC6 + PC7) works fine but UART 1 (PA10 + PA9) does not work.

I found in some old posts that in the discovery board there is a large capacitor connected to PA9 that prevents the uart from working.

Is this true? Does this mean that in my final hardware design there will be no such issue and UART 1 will work fine?

Thanks.

[Ozone · Accepted solution]

Yes, I remember that much.
The schematics are available on ST's website, check for yourself.

By the way, this is what the user manual has to say about this topic :

Always a recommended read.

[Andrew Neil]

@chkolli also in the User Manual:

https://www.st.com/resource/en/user_manual/um1472-discovery-kit-with-stm32f407vg-mcu-stmicroelectronics.pdf#page=21

via: https://www.st.com/en/evaluation-tools/stm32f4discovery.html#documentation

The User Manual tells you that both PA9 and PA10 are occupied by USB:

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@chkolli wrote:

Does this mean that in my final hardware design there will be no such issue and UART 1 will work fine?

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Yes - but you then won't be able to use USB on those pins.

Check the Datasheet to see if there are any other restrictions ...