• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 46 subscribers
  • Views 413 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.

DAC38J82EVM: Active lanes on JESD204 interface

David Becker
Prodigy 70 points
Part Number: DAC38J82EVM

I am running the TSW14J56 board connected to a DAC38J82EVM over the JESD204B interface.

When configuring the TSW14J56 using the quickstart instructions, I get the error shown in the screenshot.  I clicked "OK" and then hit "Send" again and there is no further error.  Proceeded with the next steps of resetting the DAC and issue SYSREF on the DAC GUI screen and the expected waveform (spectrum) is generated.

If I then look at the "Serdes and lane configuration" on the DAC GUI screen, it shows RX2 and RX3 as enabled - consistent with the setup of using 2 lanes.  If I disable Rx2 the spectrum disappears, but if Rx3 is disabled, everything still operates normally. 

Does this mean all the data is going down Rx2 ? 

Is the earlier error implicit in this ? 

How do I know what is happening on the JESD interface ?

  • 0
    TI__Guru* 91947 points

    David,

    The data rate you entered in the HSDC Pro GUI above is to slow for the system to operate properly. The value entered in the Data Rate (SPS) window needs either a "M" for megahertz or "G" for gigahertz after the number. I think the number you want to enter here is "368.64M". Give this a try.

    Regards,

    Jim 

  • 0 in reply to jim s
    Prodigy 70 points

    Yes, I agree there should be an "M".  I thought I read some documentation that this field only affected the FFT display at the bottom of the screen.

    I repeated the sequence from cold start with 364.68M in the SPS field and got the same result.

  • 0
    TI__Guru* 91947 points

    David,

    In this mode, RX3 data is sent to DAC A and RX2 data is sent to DAC B if using the settings from the GUI. This is why you see the output go away when you disable one of these. Take a look at the other DAC output and do the same test.

    Regards,

    Jim

  • 0 in reply to jim s
    Prodigy 70 points

    Yes, thanks Jim.  I was looking at DACB, but the other RX line controls DACA.