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Original question:

TLK10031: MDIO line is going to ground

TLK10031: MDIO port don't response and link error

user1383176
Prodigy 60 points
Part Number: TLK10031

Hello!
Our current design is to use the powerPC MDIO interface to control the TLK10031, using the clause45 mode. After the first addressing, the powerPC queries the mdio interface ready and sends a reading command. From the oscilloscope measurement results, tlk10031 has no response. The configured tlk10031 address is 0.
Both the powerPC end MDC and mdio have pull-up resistors(pull up to 1.2 V), and then connect tlk10031 by level conversion to 1.5V. The tlk10031 is required to pull up the 2K resistor according to the manual, but the measurement at this time found that the low level was not pulled to the ground. After the pull 2 K resistor is removed, the low level can be reduced to ground, but the interface does not respond.
Please respond.

  • 0
    TI__Guru 64326 points

    Hello,

    TLK10031 requires either 1.5-V or 1.8-V I/O levels on the MDIO/MDC signals. MDIO interface should be pulled up to 1.5-V or 1.8-V I/O levels not 1.2V. Other things to look out for:

    • TESTEN should be low for proper operation (TESTEN = 0). You should be able to use MDIO when TESTEN = 0.
    • Add a 33bit of 1's for preamble in the MDIO communication, this may help with your issue.
    • Ensure that you are following the MDIO frame format is as follows:
      • ST /OP / PHYADDR / DEVTYPE / TA / (ADDR/DATA)  16BITS