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DP83TC812S-Q1: link up 0x01=0x with SQI reg871=0

Dongbao Zhou
Expert 4170 points
Part Number: DP83TC812S-Q1

hello

Could you explain the possible reason of link up 0x01=0x0065 with SQI reg871=0?

1. Constant reading for tens of times with stable reading when ethernet communication doesn't work well

2. After 30min, SQI reading turns normal to 7 and ethernet link is ok (ping good), no reset/power cycle happen

3. Hard to reproduce and only happen once after SOP

Regards,

Dongbao

  • 0
    TI__Genius 14006 points

    Hi Dongbao, 

    To confirm, are you saying that:

    1. You power up the system and it links (reg 0x1=0x65),

    2. You try to ping from both PHY to link partner and link partner to PHY but it does not work

    3. You read that SQI reg 0x871[3:1]=0x0

    4. After 30 minutes, ping works

    It is difficult to explain the reason of link-up when the issue cannot be reproduced. I have some clarifying questions:

    • What is the SW configuration of the PHY (did you write to any registers)?
    • What is the failure rate - is this 1/10? 1/100?
    • By SOP, do you mean start of production?
    • Is the 812 connected to another 812?

    Next time it happens:

    • Please note down any potential cuases
    • Take a reg dump of 0x0-0x1F
    • To try ping from link partner to PHY and set 0x619[10:9] = 101 and read the rx_error registers 0x63C, 63D, 63E.
    • Try to ping from PHY to link partner and read TX regisers 0x639, 63A, 63B.

    Best regards,

    Melissa