Usart 3 not a available on NUCLEO H755ZIQ in CubeMx

[Jad]

Good morning , I have a problem on stm32: USART3 is impossible to put  into available:

the schematics of my nucleo 144 tell me however to use usart 3: 

 

I wanted to do it manually by turning directly the pins of PD9 and PD10 into tx nd rx but it doesn't want to turn on the usart3. I think I am missing something.

[SofLit · Accepted solution]

Hello,

How did you start your project in CubeMx? from MCU part number or from Nucleo board?

If it was from the board, USART is already configured for you when you selected to initialize the peripherals

PS: UART3 Tx/Rx are on PD8 and PD9 not on PD10.

[Jad]

I started it directly on IDE from nucleo.i begin from IDE since it has the gui of cubeMX now.