DP83822I: DP83822I low temperature startup issue

Wayne Wang20

Part Number: DP83822I
Other Parts Discussed in Thread: TIDA-00928

Hi team,

My customer is tesing DP83822I in a low temperature test. DP83822I is configured into RMII master MODE. They put the board in -40℃ for several hours and then power up the board. The result is some DP83822I boards can work normally but some cannot bulid up link with the partner after power up. The failure rate is 3 out of 10. For the failure devices that cannot bulid up link, we found that their Pin1 have no signal at all. But in theory, Pin1 should have a 50MHz clk output in RMII master mode. So could you please help advise what may cause this issue?

What's more, for the failure devices, we tried to disconnect the CRS_DV line from DP83822I to MAC. Then all the failure devices can build up link after start up in low temperature. So why CRS_DV line makes a difference here? Can we just leave this pin open in RMII master mode? Thanks.

Best regards,

Wayne

over 2 years ago

0 Kallikuppa Sreenivasa over 2 years ago

TI__Guru*** 141929 points

Hello Wayne

Thank you for the query.

Can you please share the schematics to review.

Can you ask customer to check if the device is being reset ? Please see below

How is the master mode configured.

If RMII Master mode is configured through bootstraps, a 50-MHz output clock will automatically be enabled on RX_D3 (GPIO3).

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 141929 points

Hello Wayne

Thank you for the inputs. I am reviewing the inputs.

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 141929 points

Hello Wayne

Based on my initial review, i sent a few question over email.

Could you please follow up and provide your inputs.

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 141929 points

Hello Wayne

Did you hear back from customer ?

Regards,

Sreenivasa

0 Wayne Wang20 over 2 years ago

TI__Expert 4360 points

Hi Sreenivasa

Sorry for the late response. We took some days and found the root cause. It is because the MAC side RX_ER PIN toggle its logic level in low temperature condition which makes the DP83822 configuration changes. We are still checking why the MAC side will toggle its logic level but at least we concludes that the issue is not related to PHY.

Best regards,

Wayne

0 Kallikuppa Sreenivasa over 2 years ago in reply to Wayne Wang20

TI__Guru*** 141929 points

Hello Wayne

Thank you for the reply and good to hear the progress.

Do you need any additional support from my side.

During the schematics review our observations were that some of the terminations around the magnetics can be improved.

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 141929 points

Hello Wayne

We have a TI design TIDA-00928 that customer can reference.

Regards,

Sreenivasa

+1 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 141929 points

Hello Wayne

If you do not have additional questions, please close he thread by clicking the resolved button.

Regards,

Sreenivaa

0 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 141929 points

Hello Wayne

I will go ahead and close the thread since i have not heard from you.

Regards

Sreenivasa

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DP83822I: DP83822I low temperature startup issue