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TLIN1021A-Q1: connecting RXD to two MCU's at the same time

Wei Xiao
Intellectual 595 points
Part Number: TLIN1021A-Q1


Tool/software:

In one of our applications, we need to have two MCU's (both STM32F105RBT6) from different modules read the LIN data at the same time. Will it have any issues if RXD pin of  one TLIN1021A are connected to two MCU's?

  • +1
    TI__Guru 54566 points

    Hi Wei,

    Yes, connecting the RXD pin to two MCUs for simultaneous reading of LIN data can lead to several issues such as bus contention as both MCUs can try to pull the line high or low simultaneously. Also, the additional loading to the RXD which can limit its' driving capability for unreliable data reception. Data collision is also possible if both MCUs try to read data at the same time and overlapping signals are received for a misinterpretation of the LIN frames. Furthermore, additional timing issue is possible as both MCUs attempt to process the LIN message simultaneously where one MCU might miss the start or end of a message.

    You may further use a multiplexer to help ensure only one MCU reads the RXD pin at a time, implement additional protocol allowing one MCU access the RXD at a time, use separate RXD lines to each MCU allowing each to receive LIN data independently, or consider using a shared memory or dedicated LIN controller that can broadcast the data to each MCU if both MCUs need the same data, thanks.

    Best Regards,

    Michael.