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DS80PCI402: PCIe Communication

Go Bravos
Expert 6090 points
Part Number: DS80PCI402

We are having issues with PCIe communication on a DS80PCI402, driving a VPX card on one side and two in series 1M iPASS cables on the other side. Does this device support any type of S/W app/circuit that allows the received eye to be observed via at the redriver device via its I2C bus?  Any recommendations for resolving other than soldering scope leads to the DS80PCI402 device pins and monitoring the eye via scope/diff probe?  The pitch of the redriver package doesn’t lend itself to easily monitor the signals at this point.

Links are Gen 2, 5G, but connect at either 2.5G or not at all.

  • +1
    TI__Guru* 93670 points

    Hi Bravos,

    This device does not have a feature to observe ongoing eye diagram through the device via I2C. 

    To look into this issue, you can turn off de-emphasis or set to zero at the beginning. Then start with the lowest EQ settings(level 1), check connectivity at Gen2, then go to the next settings. Once you go through all the settings without success, you can change RATE pin to Gen3 without de-emphasis, and sweep the EQ settings again. What you are seeing could be due to the fact we may not have enough equalization. The only available knobs are equalization, de-emphasis, and RX detect 

    Regards,Nasser  

  • 0 in reply to Nasser Mohammadi
    Prodigy 30 points

    When are the external Pins read when in PIN control mode?  Only at power up or does de-emphasis and equalization setting changes take effect immediately upon a change of state of the pins? i.e.  does the CCA need to be power cycled after changing pin voltage level for a change to take effect.

  • 0 in reply to ron Hall
    TI__Guru* 93670 points

    Hi Ron,

    Pin setting such as EQ or de-emphasis go into effect right away. On the other hand, if you use I2C register settings then you may need to do pin override before this change through I2C go into effect.

    Regards,,Nasser