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DS80PCI810: Re-driver part not working

Robert Conklin
Prodigy 50 points
Part Number: DS80PCI810

We have made an adapter card from XMC to CPCI serial. When we remove the TI part and add wires, the card seems fully functional.

I have gone over the datasheet 3 or 4 times and can't find anything that we did wrong. I accidentally left the res3 pin open, but fixed that by shorting it to EQA pin right next door. GND through a 1K resistor.

The direction of the signals appears to be good. We are using pin strap mode with the values that are on the attached schematic. The chip is in 3.3V mode, and I verified there is 2.5 volts on all the VDD caps.

I'm really out of ideas, and we are about to just remove the part. Any help would be appreciated.

Thanks in advance.

pxie-xmc-rev-b.pdf

  • 0
    TI__Guru* 88835 points

    Hi Robert,

    1). When you add wires and card system works fine, can you please get a scope shot?

    2). When device is mounted, is it possible to run at low rate like 2.5G and use your high impedance differential scope probe to check signal quality on input and output?

    3). Noticed you have RXDET floating with /PRSNT going to ground through 1K ohm Resistor. When you are running these test, do we have termination on the output of the device? I am wondering if RXDET is seeing expected 50-ohm termination on its outputs. Or you can do manual RX detect so you can monitor output waveform with your 50-ohm scope probe.

    You can send me email so we can look into this. Here is my email: Nasser.mohammadi@ti.com I think we need to probe signal along the signal path to see where our signal gets lost or corrupted.

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    TI__Guru* 88835 points

    This issue was related to one of the pins not being biased correctly. For future reference, please use the following settings:

    PWDN = 0

    RXDET = Float

    RESEVERED1 = Float

    RESERVED2 = 0

    RESERVED3 = 0

    SD_TH = Float

    VDD_SEL = 0 for 3.3V VIN operation

    VDD_SEL = Float for 2.5V external regulator operation

    Set EQ and VOD as needed for optimal signaling, Typically:

    EQA = EQB = Float or 1

    VODA1/VODB1 = 0

    VODA0/VODB0 = 1 

    Regards,, Nasser