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DS125DF1610 configuration

Madhuri Akkenepalli
Expert 1215 points
Other Parts Discussed in Thread: DS125DF1610

Our hardware design has a DS125DF1610 sitting between a switch ASIC and the SFP+ cages (plus a 2nd design that uses 2xQSFP+ instead of 8xSFP+).

 [98DX4251] --- |connector| --- [1610] --- [SFP+]

 Please help with the following questions:

 1) Initialization of CDR chip relative to channel inputs. Can we configure all of the 1610 channels before bringing up other components in the data-path or do we need to configure it as we enable the serdes output from the switch ASIC. Do we need to actively configure the line-side based on the SFP+ MOD_ABS or RX_LOS (note RX_LOS won't help when using direct attach cables).

 2) Reaction to external events. If the switch ASIC port is disabled/enabled via user command should we re-initialize the associated channel(s). Similarly if the SFP+ module is removed/replaced should we re-initialize (presumably we should if we're changing from Fibre to DAC and need to apply different parameters).

 3) Have you got any example configurations for the 1610 with SR/LR Fibre

SFP+ modules?

Thank you

 

  • 0
    TI__Genius 10320 points

    Hi Madhuri,

    I've moved your question to the High Speed Interface Applications Support Forum.

    Thanks!

    Gabe

  • 0
    TI__Expert 3050 points

    Hi Madhuri,

    For your questions:

    1) You can load the configuration settings in the device at any time, though we typically recommend that you hold the CDR circuits in reset until the system is transmitting stable data. This is done with a simple register write to channel register 0x0A with a value of 0x5C. Once the data to the DS125DF1610 is stable you can release the CDR from reset with another write to channel register 0x0A with a value of 0x50.

    2) Typically all that should be done is a CDR reset and reset release as described in the answer to question 1.

    3) I can help you to generate a quick configuration script. Can you tell me what features you would like to have configured for the various channels? Section 8.3, on page 79, of the datasheet describes some typical items that you may wish to configure as part of the initialization sequence. Please help by listing your desired configuration settings. For example, please note the channel number and desired configurations such as:

    • VOD
    • adapt mode
    • desired FIR setting (if any)
    • ref clock frequency (25 MHz, 125 MHz or 312.5 MHz -- note this is not related to your application data rate)
    • desired data rate(s)
    • cross point setting (if any)

    Mike Wolfe

    DPS APPS / SVA