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TMS320F28034: LIN port has communication problems when electromagnet work

Hank Zhang
Expert 2040 points
Part Number: TMS320F28034


When the electromagnet is working, LINTXA and LINRXA communication is not normal

When the electromagnet is working, SCITX and SCIRX communication is normal.

The schematic  is as follows:

 The abnormal waveform is as follows(green is LINTX and yellow is LINRX):

The normal waveform is as follows(green is SCITX and yellow is SCIRX)

PCB Layout(LIN port)

  • 0
    TI__Guru* 95315 points
    That an electromagnet is causing disturbance in communication, in itself, is not surprising. This is the “expected” behavior. The onus is on the system designer to implement mitigation effects (by way of proper layout, shielding, filtering etc) to protect the system.

    As to why LIN gets affected but SCI is not is a hard question to answer. This depends on many factors such as the layout involved, cable length/orientation, proximity to the electromagnet etc.

    On a different note, even your “normal waveform” of the SCI signals is extremely noisy.
  • 0 in reply to Hareesh Janakiraman
    Expert 2040 points
    Any recommendations for check
    What steps should I follow? Is there a check list
  • 0 in reply to Hank Zhang
    TI__Guru* 95315 points
    There is no “checklist”. However, there are excellent resources on our website that deal with this topic. One example is www.ti.com/.../snla016b.pdf . There are many more that you could find online. Note that much of these techniques must be employed during the design of the system. Typically, little can be done after the design is complete. Once again, I’d like to bring to your attention that even your “normal waveform” of the SCI signals is extremely noisy.