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LMK05318BEVM: 1pps into LMK05318BEVM to discipline clock

Paul Harkin
Prodigy 30 points
Part Number: LMK05318BEVM

Hi, we are attempting to use the LMK05318BEVM to discipline form a 1pps source. We have use the internal XO and an external signal generator (@12.8MHz) to no avail. With a 1pps signal on PRIREF - we are not seeing the PRIREF_VALSTAT go active. If we revert to a 25Mhz input to PRIREF we see it go active.  We are using the TICSPRO GIU as a means to check PRIREF_VALSTAT.

We are wondering what we could be doing wrong, as we would expect tthat for a 1pps @ PRIREF we should at lease see it recognized.. 

Any ideas or assistance is welcome

Thankyou

Paul

  • 0
    TI__Genius 11065 points

    Hi Paul,

    Could you provide the TICS pro configuration file (.tcs) that you used to program the device?

    Best,

    Evan Su

  • 0 in reply to Evan Su
    Prodigy 30 points

    Hi Evan,

    Thankyou the response, we will attach the file.

    How do I attach the .tcs file?

    Thankyou Paul

  • 0 in reply to Paul Harkin
    TI__Genius 11065 points

    Hi Paul,

    To attach a file, go to "Insert" --> "Image/video/file" at the bottom of the reply box.

    Best,

    Evan Su

  • 0 in reply to Evan Su
    Prodigy 30 points

    LMK05318B_TICSPro_1Hz int XO.zip

    Hi Evan, Apologies for the question (I thought it was a video insert only)..here it is. Whether we run internal XO or external the same occurs. We see a PRIREF_VALSTAT valid in the GUI only when we go to higher input freqs, 20MHz, 10MHz etc on the PRIREF. We must be misunderstanding something. Thnakyou Paul

  • 0 in reply to Paul Harkin
    TI__Genius 11065 points

    Hi Paul,

    Thanks for the file. I took a quick look and didn't see any obvious problems. The only relevant setting I know about is the 1 PPS Phase Detector on the "Ref validation" page, which is enabled for PRIREF, and all of the other detectors are correctly disabled. So in theory it should be able to pick up the low frequency signals you're testing. The only idea I have at the moment is to adjust the Counter for the 1 PPS Phase Detector (current value is 63 for T_Jitter = 1.31 us), it's possible that a 1.31 us jitter tolerance is too strict for your particular 1 PPS input and XO to satisfy. Our device expert would know better but I think she is busy today, so in the meantime feel free to experiment with the Counter and see if it helps. Hopefully she can give you more detailed guidance later this week.

    Best,

    Evan Su

  • 0
    Prodigy 30 points

    Hi Evan,

    We are still awaiting the input from the TI expert that you mentioned.

    'Our device expert would know better but I think she is busy today, so in the meantime feel free to experiment with the Counter and see if it helps. Hopefully she can give you more detailed guidance later this week'

    This is major blocker for us at the moment, so any assistance is more than greatly appreciated.

    Thankyou Paul

  • 0 in reply to Evan Su
    Prodigy 30 points

    HI Evan,

    We are still having issues with the 1pps, in that we are failing to discipline our clock source to it. Would it be possible to open this up to the device expert as you previously stated? .  or preferably a con-call to see what we could be doing wrong, as this is a major blocker for us.

    'Thanks Paul

  • 0 in reply to Paul Harkin
    TI__Genius 10555 points

    Hi Paul,

    Sorry for the delay, I have caught up on the issue internally. We will continue offline through email where I will share additional information.

    I will post the .tcs file here for you to try meanwhile.

    LMK05318B_DPLL LBW=0.01 Hz_XO=12.8 MHz_PRIREF=1PPS_OUT=100 MHz_May 30 2023.tcs

    Regards,

    Jennifer