How can I use the USART of the STM32L4R9I DISCO board?

[ukn.1]

When I configured the USART3 and LPUART1 it was going to the error handler function.

can anyone tell why that's happening.

[Andrew Neil]

@ukn.1​ "it was going to the error handler function"

Do you mean the Hard Fault handler?

Lots of resources on debugging Cortex-M Hard Faults:

https://community.arm.com/support-forums/f/embedded-forum/3257/debugging-a-cortex-m0-hard-fault

Note that this is not specific to the Disco board - the chip's internals work (and fail) the same way whatever board it's on. See this thread:

https://community.st.com/s/question/0D53W00001gY6B8SAK/the-document-about-nucleol4r5zi