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DP83TC811-Q1: RX errors on every frame

Alexander Pietsch
Prodigy 10 points
Part Number: DP83TC811-Q1
Other Parts Discussed in Thread: DP83TC811

Tool/software:

Hi Team,

i am having issues with the RX of the DP83TC811. ethtool shows it is due to CRC errors. The testsetup is:

mac <-> dp83tc811 <-> rddrone t1 adapter <-> router

I configured the dp83tc811 to be in RGMII mode. I did check the SQI register and it indicates good link status. What can i do to further debug the issue ? 

# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 96:B0:87:97:E4:BC
          inet addr:192.168.179.154  Bcast:0.0.0.0  Mask:255.255.255.255
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1433 errors:1470 dropped:1 overruns:0 frame:1470
          TX packets:333 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:101042 (98.6 KiB)  TX bytes:18314 (17.8 KiB)

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP MII ]
        Supported link modes:   Not reported
        Supported pause frame use: Symmetric
        Supports auto-negotiation: No
        Supported FEC modes: Not reported
        Advertised link modes:  Not reported
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: No
        Advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        MDI-X: Unknown
        Supports Wake-on: g
        Wake-on: d
        Link detected: yes

#ethtool -S eth0
    ...
    rx_packets: 2996
    rx_broadcast: 1430
    rx_multicast: 92
    rx_crc_errors: 1474
    ...


  • 0
    TI__Mastermind 26802 points

    Hi Alexander,

    It is my understanding that TX is having no issues, only RX is the issue? You will want to check the shift/align mode, in order to ensure proper setup and hold times are being met. Shift mode can be enabled by writing '1' to bit[12] of register 0x17. Please give this a try and let me know if it resolves the issue.

    Can you please also share the schematic with me?

    Thanks,

    David

  • 0 in reply to David Creger
    Prodigy 10 points

    Hi David,

    Thanks for your quick answer. You are right TX seems to be fine. I allready tried the RX delay but it does not improve the situation.Unfortionatlely I cannot share schematics here.

    Thanks,
    Alex

  • 0 in reply to Alexander Pietsch
    TI__Mastermind 26802 points

    Hi Alex,

    You may probe the RX_Data and RX_CLK signals with oscilloscope to to ensure the setup and hold times needed by the MAC are being met.

    Please share the schematic via direct message if that is possible, it will be important to review in order to debug this issue.

    Thanks,

    David