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DP83848 no link with stm32f107

Mehran Msba
Prodigy 130 points

Hi.

I use a DP83848w with stm32f107. ARM program and PHY work successfully for first time and I got my socket connection on Hyper-terminal, but the link led turned off when I reseted the board for debugging and it never be turn on !

I cant find any issue on software after many reset and analyze the PHY register.

BMCR is 0x3100 & BMSR is 0x7849 -> no linking

I turned off the board and turned it on again after 30 min.(I worked on other things.) Its OK again! but when I reseted, no linking available.

I tested :

1- 10M half duplex, no link.

2- loop-back cable,no link.(loop-back cable tested before with a Ethernet switch and led of switch turned on)

Its seems that my PHY cant negotiate or create active link for a reason.

whats the problem(s) ?

Thanks.

  • 0
    TI__Mastermind 31600 points

    Please send your schematics to me at (email address redacted).  I will review them to see if there are any items of concern.

    Please also post the complete register contents (register addresses 0x00 - 0x1F).  Some of the device registers latch low or high to capture status so please read each register twice before providing the register contents.

    What partners are you testing with?  What are the other PHYs for which a link is not re-established?

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 130 points

    Thats I forget to say that, Connection is RMII.

    Register Contents are:

    Address-Value

    0x00-0x3100
    0x01-0x7849
    0x02-0x2000
    0x03-0x5c90
    0x04-0x01E1
    0x05-0x0000
    0x06-0x0005
    0x07-0x2001
    0x08-0x0000
    //---------
    0x10-0x0000
    0x11-0x0000
    0x12-0x0000
    0x13-0x0000
    0x14-0x0000
    0x15-0x0000
    0x16-0x0100
    0x17-0x0021
    0x18-0x0000
    0x19-0x8021
    0x1A-0x0904
    0x1B-0x0000
    0x1C-0x0000
    0x1D-0x6011
    0x1E-0x003F

    ---------------------

    This schematic is not important design and I put schematic here (may be used for other one):

    also available on this.

    I tested with my PC(Realtek PCIe GBE Family Controller->RTL8167) and a D-link unmanaged switch(DES-1008D).both response are same.

    Thanks in advance.

  • 0 in reply to Mehran Msba
    Prodigy 130 points

    I checked register again without any good news.

    I checked ST source code example and board response was same and no led turned on. thats seems hardware has a issue.

    schematics available on previous post.

    please continue your helping.

    Thanks.

  • 0 in reply to Mehran Msba
    TI__Intellectual 1885 points

    Hello,

    Have you measured the voltage on the RBias resistor?

    Can you check the 50MHz clock source and confirm frequency?

    Thanks,

    John

  • 0 in reply to John Hamilton1
    Prodigy 130 points

    Yes.

    50MHz signal is OK (approximately sinusoidal waveform).

    RBias is 1.185Vdc. (I don't know true values.)

    Are the registers contents OK?

    Thanks.

  • 0 in reply to Mehran Msba
    TI__Mastermind 31600 points

    I do not see any issues with the register configuration.  The schematic connections look correct.  The RBIAS voltage should be ~1.2V so the value of 1.185V is reasonable.

    I have a few more recommended measurements to try:

    1. Probe the 3.3V supply pins and confirm the voltage.
    2. Probe the PFBOUT and PFBIN pins.  Confirm that the voltage at each pin is ~1.8V.
    3. Power down the board and verify:
      1. Resistance to ground across the RBIAS resistor should be 4.87 kOhms +/- 1%.
      2. Resistance across the transmit and receive terminations should be 50 Ohms +/- 1%.

    If all these values appear correct, we can evaluate the transmit signaling at the RJ-45 connector and we can run some tests with internal and external loopback (using a loopback cable) to help narrow down the source of the trouble.

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 130 points

    I can work on this board again and changed DP83848 with new one and everything were same as ago.

    I checked your test solution:

    1. 3.3 is OK

    2. PF voltages are 1.71v

    3.a) Rbias is 4.81K .

    3.b)resistance between transmit and receive can not measurable because Rj45 connector change true values. but when I checked the board I see these are 68X (49.9Ohm). measured values are ~0.6Ohm(resistors are parallel with RJ45 Trans).

    I cant fix this problem yet. whats the next step?

    Thanks.

  • 0 in reply to Mehran Msba
    Prodigy 130 points

    I set Loopback flag. Green LED turned on and link flag changed to 1.

    Its not useful because real network has problem and I cant check my software well.

  • 0 in reply to Mehran Msba
    Prodigy 130 points

    I checked everything and I changed RJ45 Connector with new one at-last.

    everything is OK now and link is available. Its seems damaged by high temperature soldering,Its not my work :) .

    Its a bad problem and may be a ridicule. but I never think that is problem.after all,I learned new thing about this chip.

    Thanks for helping.

    Happy Christmas and Have a good year.

  • 0 in reply to Mehran Msba
    TI__Mastermind 31600 points

    Thank you for providing this feedback.  I would suggest that this is a not a very common source of communication problems.  I commend you for your diligence in working through all the possibilities and driving this to a successful conclusion.

    Patrick