DP83822I: reading out different register values right after writing

Part Number: DP83822I

Hi,

My customer is using DP83822I and facing the phenomenon below,

・During test that repeating READ and WRITE to the same register via MDIO, The reading values are sometimes different from the last writing values.

Incidence rate：0.1% ( About 100 times out of 100,000 cycles)

1. In the customer's case, The 2.2kΩ Pull-up resistor that is required on MDIO line is placed a little far from MDIO pin of DP83822I.

(the 2,2kΩ is placed on different board, and these 2 boards are connected with 10cm FCC cable)

Would it be the possible cause of this phenomenon?

2. About the incidence rate, Does this rate could be considered as a normal range?

Thanks,

0 Hillman Lin over 1 year ago

Hi Go,

May I ask which register specifically is different from last writing. The reason I am asking this because there is some register have latch up or latch down feature that will record previous register status
as long as MDIO have 2.2kohms and MDC does not have 2.2kohms pull up. MDIO communication should be fine.
I think MDIO communication should be really stable.

Regards,

Hillman Lin

0 Go over 1 year ago in reply to Hillman Lin

Genius 4220 points

HI, Hillman-san

Thank you for your comment.

I'll confirm with my customer which register specifically is different, and get back to you.

Thanks

0 Gerome Cacho over 1 year ago in reply to Go

Hi Go,

Hillman is OOO and will be responding tomorrow.

Sincerely,

Gerome

0 Hillman Lin over 1 year ago in reply to Gerome Cacho

Hi Go,

I will wait for customer's response.

Regards,

Hillman Lin

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