• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 46 subscribers
  • Views 641 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Trouble configuring DAC37J82evm with more than 2 lanes.

Dan Van Winkle
Intellectual 320 points
Other Parts Discussed in Thread: DAC37J82EVM, DAC37J82, DAC37J84EVM

Hi,

I've successfully set up the eval board to generate a 20MHz signal using the following simple set up.

  

However, when I try to up the DAC rate to twice that value using the following setup.

I get a waveform that is completely messed up.  I've tried a lot of different things, and it does seem directly related to the number of lanes I'm using.  

Thanks for any help.  This is driving me nuts!

  • 0
    TI__Guru 66054 points
    Hi,

    I have tested the DAC37J82EVM with TSW14J56EVM at 737.28MSPS data rate like you had, and the setup was working as expected. Please advise if you are using similar setup as described in the EVM user's guide (i.e. with TSW14J56 rev B board).

    -Kang
  • 0 in reply to Kang Hsia
    Intellectual 320 points

    Yes, I'm using the exact setup in the EVM user's guide.  And as I said, it works fine with the lower sample rate.  It seems to be only related to the number of lanes I tired.  In fact, I have two of the TSW14J56EVM cards and I tried both of them.  They both had the same problem, so my guess is that it is some issue with the DAC37J82EVM card.  This only occurs when I increase the number of JESD lanes.

  • 0 in reply to Dan Van Winkle
    TI__Guru 66054 points
    Hi,
    If you can provide a test matrix table indicating which settings worked for you and which one doesn't, it will be helpful for me to narrow down the issue. Right now I can only confirm that both the settings that you have pasted in the original forum post worked on my setup. It is hard for me to understand your setup if both data rate and number of lanes are the variables.
    Please also advise your preferred setting for your end application. If it is a DAC EVM issue, I can test your setting here and send you an EVM replacement just to be sure that it will work on your setup over there.

    -Kang
  • 0 in reply to Kang Hsia
    Intellectual 320 points

    OK, Here is a more straightforward comparison.  I generate a 20MHz sine wave using the following settings for the DAC:

    I get the following response on the output:

    Then with this setup:

    I get this:

    The only difference is the number of lanes.    Thanks for helping with this.

  • 0 in reply to Dan Van Winkle
    TI__Guru 66054 points

    DAC37J82EVM_SETUP_368p64MHzinput.pptxHi,

    I have tested the DAC37J82 with 368.64MSPS input, onboard clocking, and three different JESD modes of 821, 421, and 222 modes. All the modes are functional for my setup.

    Please see attached powerpoint for both HSDC PRO setup and DAC GUI setup. Could you check your HSDC PRO setup to see if you have selected the correct LMF setting from the drop down menu? Assuming the DAC37J84EVM and TSW14J56EVM are both functional, this is the only variable that could cause the glitch shown above. All of our boards were tested after manufacturing. Did you happen to change anything on the DAC board?

    Also, what is the HSDC PRO GUI version and the TSW14J56 hardware revision number? We can try to track down if there are any hardware changes. I have an internal release HSDC PRO version 3.058 with TSW14J56 rev B. The internal release software should not impact the operation of TSW14J56 rev B.

    Please let me know any difference you see on your HSDC PRO GUI setup. If this still does not work, I will send you my DAC37J82 EVM for you to try out.

  • 0 in reply to Kang Hsia
    Intellectual 320 points

    OK, I see where my problem has been!  It finally took seeing your setup to understand.  In the HSDC pro window, under device select, I didn't understand that you need to set the Device to a different "device" each time you changed the mode (821,421 etc).  Once I did that, everything worked perfectly.  Thank you for your help!

  • 0 in reply to Dan Van Winkle
    TI__Guru 66054 points

    Hi Dan,

    Yes, the LMFC settings for the HSDC PRO would have to match the settings of the DAC GUI in order to operate correctly. Glad to hear that you have the setup working.

    -Kang