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TIDA-00306: Configure as Media Converter without any MCU

Xiaobing (Eric)
Intellectual 895 points
Part Number: TIDA-00306
Other Parts Discussed in Thread: DP83869HM, DP83849IF,

Hi team,

 I would like to try DP83869HM to design a Media Converter from Ethernet (100M) to fiber. How do I configure the DP83869HM to interface for a copper Ethernet connection to a fiber without any MCU? The function diagram as following for reference. 

BR,

Xiaobing (Eric)

  • 0
    TI__Genius 9920 points

    Hi Eric,

    We have strapping options available to configure to media converter mode. You can use the app note below as a guide:

    Thanks,

    Cecilia

  • 0 in reply to Cecilia Reyes
    Intellectual 895 points

    Hi Cecilia,

     Noted with thank you.

     I have some questions in note, if DP83869HM peripheral has been configured as table 12 requirements,  whether the "note-0x01EC" register must be configured? How to understand this "important notes"?

     In my application, there is not any MCU to configure DP83869HM's register, whether DP83869HM is good one solution? Any other chip suggestion? Thank you. 

     "NOTE: Important: Required register configuration for 100 Mbps Media Converter mode: - Write 0x1FFC to register 0x01EC (set bit [0] to 0)".

       

     Plus: I noted DP83849IF could convert 1000BASE-X and 100BASE-FX Fiber protocols without any register configure, can I have DP83849IF's strapping option notes to learning? Thanks. 

    BR,

    Xiaobing (Eric)

  • 0 in reply to Xiaobing (Eric)
    TI__Genius 9920 points

    Hi Eric,

    The strapping options should be available in our datasheet for the DP83849. If you have further questions after reviewing the datasheet you can let me know

    Thanks,

    Cecilia

  • 0 in reply to Cecilia Reyes
    Intellectual 895 points

    Hi Ceilia,

     Noted with thanks, Cecilia. 

     I'm try to use DP83849IF to finish 100BASE-TX to100BASE-FX media converter without any register configuration. Any suggestion for how cut "TIDA-00306" schematic, which just finish a conversion of copper to fiber and vice-versa at 100Mb/s. How deal with MAC datasheet interface, serial management interface, JTAG interface and so? Pls suggestion. Thank you.  

    BR,

    Xiaobing (Eric)

  • 0 in reply to Xiaobing (Eric)
    TI__Genius 9920 points

    Hi Eric,

    Can you explain more about what you mean by "cutting" the schematic? The TIDA schematic as well as the DP83849IF datasheet should also show you how to strap to the different modes as well as help you with the connection on the SMI. Does your design require JTAG and a special configuration for SMI?

    Thanks,

    Cecilia

  • 0 in reply to Cecilia Reyes
    Intellectual 895 points

    Hi Cecilia,

     Here is my application diagram. Two PHY interface will interconnected through printed circuit board traces. The Profi-NET module and DP83849IF will be less than 10cm apart.

     (1) Current-mode with voltage-mode PHY connection, Capacitor isolation or transformer isolation,

     (2) Voltage-mode with voltage-mode PHY connection, could directly connection.

     (3) Current-mode with current-mode PHY connection. 

     I see some application notes for(1), (2), but no more solution for item 3. Unfortunately, both Profi-NET module and DP83849IF PHYs interfaces are current-mode types. Could you give any robust suggestion to remove transformer and simplify the PCB layout? Thank you. 

     

  • 0 in reply to Xiaobing (Eric)
    TI__Genius 9920 points

    Hello Eric,

    Because the DP83848 is a current mode line driver you will need the termination resistors and bias network.

    I will need to discuss with our design team whether or not the transformers are needed however because of the isolation I do believe you cannot remove them.

    Thanks,

    Cecilia

  • 0 in reply to Cecilia Reyes
    TI__Genius 9920 points

    Eric,

    I spoke to our internal team in regards to this. Standard application would require both transformers as you have described above. However, the DP83849 has been tested with capacitive coupling instead of the transformer. While this could be an option I suggest you review the app note about the details and information in regards to capacitive coupling and possible limitations.

    https://www.ti.com/lit/an/snla088a/snla088a.pdf

    Thanks,

    Cecilia

  • 0 in reply to Cecilia Reyes
    Intellectual 895 points

    Hi Cecilia,

     Noted with thank you. I think above questions could be closed. thank you again.

     By the way, do you have any reference note to describable the current mode line driver and voltage mode line driver for PHY, such as how it work, how it output 1 Volts (100M) and etc.? Thanks. 

    BR,

    Xiaobing (Eric)

  • 0 in reply to Xiaobing (Eric)
    TI__Genius 9920 points

    Hi Eric, I do not believe we have an application node describing this however you may be able to find existing E2E threads on this topic.

    If you believe this thread is closed please select TI has resolved my issue.

    Thanks very much!

    Cecilia