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Original question:

DP83869HM: profinet support

DP83869HM: DP83869HMEVM in SGMII mode

inya_lake
Intellectual 295 points
Part Number: DP83869HM
Other Parts Discussed in Thread: DP83869, , DP83867CS

Hi,

 I've DP83869HMEVM and would like to put into SGMII mode. I've put SMA connectors as well as removed per instructions on section 4.2

After that, I'd like to know how to put into EVM application#2 according to table2.

My ultimate goal is to connect back to back SGMII. I'll get there but I'd like to know how to set PHY into SGMII 2 mode first. Thanks,

  • 0
    TI__Expert 7040 points

    Hi Lu,

    You can use the following register configuration shown in section 9.4.8 of the DP83869 datasheet to put the PHY into SGMII to Copper mode:

    After configuring register 0x01DF=0x0006, perform the following operations.

    • Write 0x1140 to register 0x0000

    • Write 0x5048 to register 0x0010

    • Write 0x0B00 to register 0x0009

    • Write 0x1140 to register 0x0C00

    • Write 0x4000 to register 0x001F

    Regards,
    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 295 points

    Hi Justin,

     Thank you. I was able to write to registers. Ultimately, below is what I want to test. I wanted to make sure SGMII to copper mode is the correct configuration for below application.

    Basically, SGMII data is transmitted through TX and RX differential lines and received at the other end. TX and RX are swapped. Please let me know if I need to configure additional registers. Intended speed is 100Mbps.

    Thanks,

  • 0 in reply to inya_lake
    Intellectual 295 points

    the system diagram is attached. Not sure you can see it from my previous message.

    Thanks again.sgmii_block_diagram.pdf

  • 0 in reply to inya_lake
    TI__Mastermind 39825 points

    Hello,

    Justin is currently on vacation. We expect to have a response around next week. Thank you for your understanding.

    Sincerely,

    Gerome

  • 0 in reply to Gerome Cacho
    Intellectual 295 points

    Hi Justin,

     Hope you had a great vacation. I tried to connect 2 PCs per my system diagram but didn't work. One thing I noticed was that, register 0x0009 keep going back to 0x0300 instead of 0x0B00 after power cycle. Not sure that is an issue. Please let me know if you had time to review my system and also let me know your thoughts. We have a customer waiting for proof of concept results. Thanks.

  • 0 in reply to inya_lake
    TI__Expert 7040 points

    Hi Inya,

    Registers will have to be written after each Reset or Power cycle. Writing register 0x001F=4000 will perform a hardware restart to restart the PHY while maintaining non-default register settings.

    Regards,

    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 295 points

    Hi Justin,

     The 2 EVBs are talking via SGMII. Thanks for your comments and clarifications. I'd like to talk to you about production and signal levels. For production boards, how can I configure it so that it goes to SGMII mode right away after power up. I'd like to avoid MCU writing registers if possible. Is there a resistor configuration that I can setup permanently on my production board? Also, is there a way to increase SGMII signal level if I want to to compensate for longer wires and so on. 

    Thanks. 

  • 0 in reply to inya_lake
    TI__Expert 7040 points

    Hi Inya,

    Yes, Table 12 of the DP83869HM datasheet gives the strap configuration that can be set to boot the PHY into SGMII to Copper mode.

    There is not a setting to increase the SGMII output swing on the DP83869.

    Regards,
    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 295 points

    Thank you. I'm thinking of using DP83867CS due to cost reasons. I do not see any issues with SGMII to copper mode in this DP83867CS unless you are aware of something I'm not. If you see any potential differences, please let me know. 

     Is there a way for me to submit schematics for review. I want to make sure strap resistors are configured properly. Thanks,

    Lu

  • 0 in reply to inya_lake
    TI__Expert 7040 points

    Hi Inya,

    The DP83867 can also support SGMII to Copper operation, I don't see any issue with selecting that device for your application. I would suggest creating a new thread to address strap selection and specific questions you have regarding straps when the schematic is ready.

    Regards,
    Justin