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AM62L: MDIO level abnormal issue

zhang pan
Prodigy 30 points
Part Number: AM62L
Other Parts Discussed in Thread: DP83867IR

Tool/software:

Our board has two phy DP83867IR mounted on the MDIO interface.
At present, during the cold start test of the board, there is a situation where the mdio bus registration fails, as shown in the figure below. When the problem occurs, the clocks of MDIO and MDC are always in the following state, indicating that the MDIO level is obviously incorrect:

It will print the following kernel log when the issue occur.

[ 1.341594] davinci_mdio 8000f00.mdio: davinci mdio revision 17.7, bus freq 1000000

[ 1.445718] davinci_mdio 8000f00.mdio: timed out waiting for user access

[ 1.552758] davinci_mdio 8000f00.mdio: timed out waiting for idle

[ 1.558865] davinci_mdio 8000f00.mdio: probe with driver davinci_mdio failed with error -5

  • 0
    TI__Guru**** 188699 points

    Hello Zhang Pan,

    Thank you for the query.

    zhang pan said:
    Our board has two phy DP83867IR mounted on the MDIO interface.

    Can you please verify if unique address are configured.

    zhang pan said:
    At present, during the cold start test of the board, there is a situation where the mdio bus registration fails, as shown in the figure below. When the problem occurs, the clocks of MDIO and MDC are always in the following state, indicating that the MDIO level is obviously incorrect:

    Can you confirm if the interface works some time and does not work some times or does not work any time?

    Can you describe the waveform?

    Do you have any capacitor load connected on the signals.

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Prodigy 30 points

    It can be confirmed that the address is unique because it occasionally does not work, but most of the time it works normally。
    The above image shows the waveforms measured on MDC (yellow) and MDIO (blue) when a problem occurred.

    There is no capacitor load connected to the signal.

  • 0 in reply to zhang pan
    TI__Guru**** 188699 points

    Hello Zhang Pan,

    Thank you 

    Can you please share the frequency of the occurrence - every 20 power cycles or 10 power cycles etc.

    Is the issue seen on a specific board or on multiple boards?

    Regards,

    Sreenivasa