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DP83848VV halts on autonegotiation

ellhasya gest
Prodigy 75 points

Hello,

I have two different boards that deploy DP83848VV greth phy. One is working but the other is not. I read regisiter 0x00 and got different result from both board. The working one returns 0xa100 while the other returns 0xafbf. After that, the program halts in the autonegotiation process. 

I tried to produce the same error with the working board. The error could be produced when i set greth physical address differently from its physical configuration. I double checked this issue on the other board and could not find any problem. I also have checked some parameters as mentioned at

http://e2e.ti.com/support/interface/industrial_interface/f/142/p/234583/901770.aspx and 

http://e2e.ti.com/support/interface/ethernet/f/903/t/196021.aspx. Those parameters seems okay.

I think there must be some errors in the physical configuration but could not find it. Where should i begin with?

Thank you in advance

  • 0
    TI__Mastermind 31600 points

    The register values read back from both boards appear to be incorrect.

    Could you confirm the value read back from the good board and determine if the value of 0xa100 is repeatable over multiple reads?  The fact that bit 15 is a '1' would indicate that the device is in reset.

    The value read back from the bad board indicates that bits 5 through 0 are all 1, but these bits are read only bits that default to 0.  Bits 5 through 0 should never read back as 1s. 

    You mention that you checked some parameters based on other E2E posts.  Could you provide specific details on the parameters that you checked and their values? 

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 75 points

    Sorry, there is a mistake. Here are the actual value for working board  :

    Register 0x00 = 0x3100
    Register 0x10 = 0x4115
    Register 0x17 = 0x1
    Register 0x19 = 0x8023

    The other board results 0xffff for those registers.

    Here are the parameters :

    PFBIN1, PFBIN2, and PFBOUT : 1,74 volt

    RBIAS : 4,88k and Voltage RBIAS 1,2 volt

    RX_DV/MII_MODE : 0v --> configured as MII mode

    I also add pull-up resistor to PHYAD1, that gives the phy address value of 3.