Hi @coder_72
Have you tested any SDK example?
However, the way you are using the function in your code could be causing the issue, if you read the brief description of the "Usart_TransferReceivenonblocking" function it says "This is a non-blocking function, which returns without waiting for all data to be received." I recommend you to use the unique Transfer and Recieve functions, you could take ideas from the usart_polling_example.
Let me know if you have another question.
Best Regards, Miguel.