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DP83867IR MII no TxClk

Sven Reihm
Prodigy 45 points
Other Parts Discussed in Thread: DP83867IR

Hello,

we are trying to bring up a board containing two DP83867IR. We want to use them in MII mode. Accessing the registers via MDIO works fine. Receiving data via MII works fine as well. However, the Chip does not output a TxClk. Instead, that signal is always Low.

The RX_CTRL pin of both Phys are connected to strap resistors to set them to 3. The RX_D2 pin of one Phy is connected to strap resistors to set it to Mode 3. No other pins are connected to strap resistors. Use of MII is set via MDIO:
* Bit 7 in Register 0x32 is cleared, which should enable GMII
* Register 0x9 is set to 0, which should force autonegotiation to use MII

How can we get the chip to output the TxClk?

Regards,
Sven Reihm

  • 0
    TI__Mastermind 31600 points
    Sven,

    Could you provide the register contents for some of the key configuration and status registers? The values for the following registers would be a good start:
    0x0000, 0x0001, 0x0009, 0x000A, 0x0010, 0x0011

    Thanks,
    Patrick
  • 0 in reply to Patrick OFarrell
    Prodigy 25 points
    Hi,

    I am working with Sven on the project. The register values are:

    reg 0x00: 1140
    reg 0x01: 796D
    reg 0x02: 2000
    reg 0x03: A231
    reg 0x04: 01E1
    reg 0x05: CDE1
    reg 0x06: 006D
    reg 0x07: 2001
    reg 0x08: 0000
    reg 0x09: 0000
    reg 0x0A: 0000
    reg 0x0B: 0000
    reg 0x0C: 0000
    reg 0x0D: 401F
    reg 0x0E: 00D0
    reg 0x0F: 3000
    reg 0x10: 5048
    reg 0x11: 6C02
    reg 0x12: 0000
    reg 0x13: 0000
    reg 0x14: 29C7
    reg 0x15: 0000
    reg 0x16: 0000
    reg 0x17: 0040
    reg 0x18: 6150
    reg 0x19: 4444
    reg 0x1A: 0002
    reg 0x1B: 0000
    reg 0x1C: 0000
    reg 0x1D: 0000
    reg 0x1E: 0002
    reg 0x1F: 0000

    Regards,
    Jakob
  • 0 in reply to Patrick OFarrell
    Prodigy 45 points
    Hello,

    We both reviewed the datasheed again but couldn't find a hint where the error might be. Are there some additional things we could check besides the register values?

    Thanks,
    Sven
  • 0 in reply to Patrick OFarrell
    Prodigy 25 points
    Hi Patrick,

    on one Board, we added a Strap Resistor to pull up RX_D6. With that patch, a TX_CLK is correctly generated. However, we are still not able to correctly enter MII mode by only changing register values.

    Can you help us in doing so?

    Regards,
    Jakob
  • 0 in reply to Jakob Wenzel
    TI__Mastermind 18425 points
    Hi Jakob,

    If I understand correctly, adding a pull-up resistor to RX_D6 solved the problem. What mode did you strap it to, Mode 3 or Mode 4? Also, could you comment if there are any other pull resistors on the strap pins fo the PHY. Sometimes these resistors are internal to any MAC connected to the PHY.

    Lastly, can you check if Register 0x32 was correctly configured to 0x00 before and after adding the RX_D6 strap?

    -Regards,
    Aniruddha