I am using stm32f429 , i am getting error while i am doing RX operation, I am able to perform TX operation. USART1 is not even updating the register value during debug operation. if anybody has faced same situation please share answer.

[S.Ma]

Start from an example, prefferably LL style (low level).

And if you do debug with breakpoints, remember that if you display the USART registers on debug watch window, this will actually read the HW register...

[Bob S]

We need more information. Start with basic debugging and "how to ask smart questions" (http://catb.org/~esr/faqs/smart-questions.html). What error are you getting? What does your code do (can you post it here in the forums)? What have you tried so far? Have you looked inside the HAL functions to see what might be causing that error and/or have you stepped through the code with your debugger to see why it fails?

[Jack Peacock_2]

Make sure you have the USART1 peripheral clock enabled in RCC. If USART registers don;t update it's often because there's no peripheral clock to load those registers.

Jack Peacock

[Tesla DeLorean]

Primary problem is you're probably using the API in a half-duplex mindset. The RX and TX operation can and should occur concurrently. I guess you're a HAL/CubeMX user, the hardware works fine.