Inquiry Regarding DMA Transmission Interference Between LPUART0 and LPUART1 (LIN Channel)

[dongxun]

Dear NXP Team,

  Hello! I am currently working on a project utilizing the LPUART0​ instance for asynchronous UART data transmission with DMA. Additionally, LPUART1​ is configured as a LIN channel​ for communication with a slave device. I have encountered an issue where activating the DMA-based data transmission on LPUART0​ appears to interfere with the transmission process of LPUART1 (LIN channel). Specifically, I have traced the problem to the function Lpuart_Uart_Ip_StartSendDataUsingDma(), which suggests that the DMA Tx interrupt​ may be a contributing factor.

   Could you please help clarify why two separate LPUART instances might experience this type of interference, leading to LIN transmission errors (note: LIN reception remains unaffected)? Any insight into the potential root cause or recommendations for resolving this conflict would be greatly appreciated. Thank you for your time and assistance.

Best regards,

DongXun

[danielmartynek]

Hi @dongxun,

Hard to say from the limited description, but since the LIN transmission is timing‑sensitive, have you tried using a higher interrupt priority for the LIN channel?

You did not mention what MCU part you use. But the DMA has also configurable priorities (fixed mode or round-robin) and bandwidth.

There could be also a bug in the RTD. Please specify the RTD version.

Regards,

Daniel