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Getting DS110DF410 to lock at 11.049Gbps

Travis Lantz
Prodigy 40 points
Other Parts Discussed in Thread: DS110DF410

Hello!

We are using a DS110DF410 in a new application.  We are successfully using it at OC-192 (9.953Gbps) and 10GbE, however, we would like to run the device at 11.049Gbps.

I am having trouble figuring out the register values that I will need to program correctly.  In reading the data sheet, it looks like for 11.049Gbps, that would make Nppm = 14143 or so, or 0x373F in hex.  I believe that is the value I should put in both registers 0x60, 0x61 and 0x62, 0x63.  Is that a correct calculation?

However, I am not sure what I need to put into register 0x2F, as the only reference for these values is table 1?  Should I select the highest data rate from the table, or is there a method to calculate the value for 0x2F based on the data rate.

Thanks!

  • 0
    TI__Expert 3175 points

    Hi

    We are looking into this post. The AE of this device will send out a reply soon.

    Regards,

    TK

  • 0
    TI__Mastermind 19235 points

    Hi Travis,

    To configure the DS110DF410 for 11.049 Gb/s operation you must write the following values to channel registers 0x60-0x64 (after selecting your desired target channel):

    0x60 -> 0x3F

    0x61 -> 0xB7

    0x62 -> 0x3F

    0x63 -> 0xB7

    0x64 -> 0xEE

    (use a mask of 0xFF for all of these individual writes above.) 

    No write to channel 0x2F should be needed. I double checked these writes above in the lab with a DS110DF410 EVM and can confirm that it works (i.e. I was able to lock to 11.049G.)

    Regards,

    Rodrigo Natal

     

  • 0 in reply to Rodrigo Natal
    Prodigy 40 points

    Hello Rodrigo!

    Thanks for the answer.  Those value work great, and I can get the CDR to lock at 11.049G in our lab now.

    Can you explain how you determined the values to load into registers 0x60, 0x61, 0x62, and 0x63, as I don't get the same values that you listed when I follow the method in the data sheet to determine Nppm.

    Also - it looks like with the EVM the default value for register 0x2f is 0x06, which doesn't correspond to a data rate listed in table 1.  Can you load other values beside those in table 1 in register 0x2f, and if so, how do you calculate what that value should be?

    Thanks!

  • 0 in reply to Travis Lantz
    TI__Mastermind 19235 points

    Hi Travis,

    For figuring out the values for registers 60-63 you were almost there. The missing piece is that registers 61 and 63 needed their bit 7 to be asserted. Bit 7 for these two registers is the 'Override enable for group manual data rate selection.'

    Related to the value for register 0x2F for custom/manual setting, you need to first refer to the 'Divider Ratio Settings versus Register 0x2f Setting' table in the DS110DF410 datasheet. Typically you would select a divider grouping from that Rate/Sub-rate Table and program that value to channel register 0x2F. When calculating the two group settings, you want to account for your desired data rate and divider. Specifically, for parameter F1 (which is the frequency of the VC0 corresponding to the desired data rate) if the target data rate uses dividers, then you would multiply the data rate by the divide setting to get the correct VCO frequency

    Regards,

    Rodrigo Natal