DP83620: MDC to MDIO Time Delay Issue

Palanikumar E

Part Number: DP83620

Hi Experts,

In our Project, we are using DP83620SQE/NOPB Ethernet Transceiver (RMII mode). During DVT Testing of Ethernet section, We have identified failure in MDC to MDIO (output) Delay Time with respect to Datasheet.

Instead of Max delay time of 20ns we are observed 413ns Delay time. Please find the attached image for your analysis.

We have also observed the MDC Clock as 650.1kHz. Please find the attached image. (As per Datasheet MDC Frequency: Typ 2.5MHz to Max 25MHz)

1. We are suspecting the MDC to MDIO Higher time delay because of MDC Clock is very low (700khz). Compared to Typ 2.5MHz to 25MHz they have mentioned. Please let us know is that true?

2. As we checked the MDC Clock is TI Driver based and fixed, seems it couldn't be configured to 25MHz. Is there any option to increase the MDC Clock frequency to 25MHz as mentioned in Section 4.7 Table?

Please provide inputs on the same

Thanks and Regards,

Palanikumar E

10 months ago

0 Gerome Cacho 10 months ago

TI__Mastermind 31755 points

Hello,

Thank you for your response. Please note the US offices are closed for Thanksgiving Holiday and will look to reopen next week.

Sincerely,

Gerome

0 Palanikumar E 10 months ago in reply to Gerome Cacho

Prodigy 50 points

Thanks for the update. I hope, will get the answers today.

0 Hillman Lin 10 months ago in reply to Palanikumar E

TI__Mastermind 22215 points

Hi Palanikumar,

Gerome is currently out of office and will provide you an response with in this week.

Thank you for understanding.

Regards,

Hillman lin

0 Gerome Cacho 10 months ago in reply to Hillman Lin

TI__Mastermind 31755 points

Hello,

I would like to preface that this device is an older device, and support is limited to datasheet.

MDC is an input to the PHY, so this is an SoC issue.

Regarding image 1, I have no way of determining if this is during the time when the PHY is supposed to be responding upon the second portion of SMI communication, or the first. I would need the entire waveform annotated clearly, along with a zoomed in photo of the SMI communication post turn-around.

If you did speed up the SMI communication, would this help resolve issues?

Sincerely,

Gerome

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DP83620: MDC to MDIO Time Delay Issue