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TLK2711-SP: Microsemi FPGA SERDES communication with TLK2711-SP at 2Gbps

user6391387
Prodigy 40 points
Part Number: TLK2711-SP

I would like to have a Microsemi FPGA SERDES (IGLOO 2 and RTG4) connect with a TLK2711-SP.  The FPGA SERDES TX will connect to the TLK2711-SP RX.  Can I connect the TLK2711-SP RXCLK recovered clock to the TXCLK for transmitting back to the Microsemi FPGA SERDES RX?

  • 0
    TI__Mastermind 19235 points

    Hi,

    Related to: "Can I connect the TLK2711-SP RXCLK recovered clock to the TXCLK for transmitting back to the Microsemi FPGA SERDES RX".

    • Yes, you should be able to

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • 0 in reply to Rodrigo Natal
    Prodigy 40 points

    Thanks for the quick response Rodrigo!

    I have a few other questions related to this interconnect scheme.  I plan to send comma characters at regular intervals on the LSB side.  How many successive comma characters are needed to guarantee byte alignment / sync?  And if more than one comma is needed, do they have to be the same one or can I use K28.1 followed by K28.5 as an example? (I recall the datasheet stating that K28.1 is required as a minimum).

    Lastly, I also plan to monitor the RKMSB and RKLSB signals along with the LSB Rx bus as a means to monitor for bit errors. Will this approach allow all single bit errors to be detected?

    Thanks,

    -Tom O 

  • 0 in reply to user6391387
    TI__Mastermind 19235 points

    The TLK2711 as specified will achieve a BER of 1E-12 or better. This means there could be a single bit error in 10^12 bits. This bit error could cause loss of synchronization. The one way to get synchronized again, is with the comma.

    The TLK2711 is very similar to fiber channel, and can receive valid FC data. It cannot transmit valid FC data due to unique running disparity changes FC employs.

    Fibre Channel frames typically have a maximum payload size of 2112, and with with headers makes the MTU 2148 bytes. However you can increase the payload up to 9000 bytes, and with headers that 9036 bytes. You can set your own frame size since you are essentially customizing your own protocol based on your system needs. You should only need one comma in between max data payload iterations. Multiple commas should not be needed.

    I believe that monitoring RKMSB and RKLSB should be sufficient.

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • 0 in reply to user6391387
    TI__Mastermind 19235 points

    Hi,

    My apologies as a colleague of mine corrected me on my assumption. TI does not recommend using the recovered clock to drive the gtx_clk on same device. The jitter will be too high in such a configuration.

    Cordially,

    Rodrigo

      

  • 0 in reply to Rodrigo Natal
    Prodigy 40 points

    Hi Rodrigo,

    Thanks for letting me know.  So I will either need to send a low-jitter clock along with the SERDES lanes or identify a low power jitter cleaner that is also rad hard.

    Thanks,

    -Tom O