Effect of Cable errors of TJA1100 on the link status

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Effect of Cable errors of TJA1100 on the link status

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Contributor I

Hello All,

We are using the TJA1100 as a PHY with MPC5746C in an Automotive project.

I need to test the behavior of the cable errors: ( Short/open circuit) of the two wires of the cable on the link status.

I mean: what will be the link status once I forced a cable error on the wires ?
shall it the link be in down stats or what ?

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4 Replies

NXP TechSupport
NXP TechSupport

Yes, the TJA1100 provides a "cable test" feature. Details how it can be used can be found in section 6.10.2 of the data sheet.
If a cable problem happens during normal operations, it will be signaled by LINK_UP status bit that will changed from 1 to 0. LINK_STATUS_FAIL interrupt is generated by the PHY in such a case.

Regards,

Bulat

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Contributor I

Hello Bulat,

Thanks for your reply.

Still I have some points to be clarified:

  1. What is the duration in seconds of applying the cable error after which the PHY will be able to detect the error ? " because I monitored the behavior of the PHY and saw that it takes some seconds to realize the error"
  2. When the error is removed, shall the PHY report that the error is removed? " by resetting the corresponding bit in the status register", because I saw that after removing the error the PHY didn't clear the bit in the status register and the error still be reported.
  3. After removing the error, the Link_Up bit shall change from 0 to 1 again ?

Could you please clarify the questions in the same arrangement

Thanks

Ahmed Saber

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NXP TechSupport
NXP TechSupport

What are the pin strapping setup of your PHY?

Regards,

Bulat

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Contributor I

Hello Bulat,

sorry for the late reply, please find my answer in the screenshot of the PHY datasheet

as labelled in Yellow color

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