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DP83822IF: I would like to inquire about setting DP83822IF fiber??

jihoon kim
Prodigy 10 points
Part Number: DP83822IF

hi.

Strap set up for DP83822IF fiber drive

After testing, the pull-down straps of RX_D0 and RX_D1 did not work properly

If the pull-down strap of RX_D0, RX_D1 is applied with RH 2.49K pull-up resistance, it is set datasheet  mode 4 

If you check the actual register Set to Mode_1

Is the data sheet wrong?

Datasheet does not say to use pull-up 2.49k for RX_D0 and RX_D1 when using Fiber mode

Please check with the company

  • +1
    TI__Mastermind 34085 points

    Hello,

    To use fiber application, COL is the pin which should be set to Mode 3 or 4. Can you please share where RX_D0 and D1 play into Fiber application?

    It may be helpful to consult our DP83822 troubleshooting guide for common design errors. In addition, our schematic checklist has recently been uploaded to assist with recommended connections and desired strapping.

    Sincerely,

    Gerome

  • 0
    Prodigy 10 points

    The strap setting is configured like a red box.
    The default mode setting of the pull-down strap is not possible.
    Mode-4 is recognized as Mode 1 when set.

    <- Pull-down MODE Open : mode 2 set

    <- Pull-down MODE 4 set : mode 1 set

  • 0 in reply to jihoon kim
    TI__Mastermind 34085 points

    Hello,

    It appears that something else may be driving the line which may be interfering with the biasing of the resistor network. I would recommend holding the PHY in reset AND ensuring that the MAC is quiet on these lines. Thus the only thing theoretically biasing the line for strapping purposes would be the network.

    Sincerely,

    Gerome

  • 0 in reply to Gerome Cacho
    Prodigy 10 points

    Hello.

    I saw what you sent me.
    According to the document SNLR053 you sent, the RX_D0 strap is selected as Mode_4 when looking at the part that is enabled for the strap setting.

    Where is this in the data sheet?

    The data sheet does not say to select RX_D0 pin as Mode_4 when using Fiber mode.

    Is it correct to set the RX_D0 pin to Mode_4 when using Fiber Mode?

    If that's right, I think the data sheet should have this.

    It's an important part, so please check it.

  • 0 in reply to jihoon kim
    TI__Mastermind 34085 points

    Hello,

    If you notice closely, the PHY address, specifically PHY_AD1 will heavily influence RX_D0 which is in line with the datasheet. Please input all fields as per your design requirements to get the appropriate strap selections. If there is something that contradicts datasheet, then we can discuss further.

    Sincerely,

    Gerome