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LMX2492EVM: Problem configuring the VCO frequency

Danilo A.
Mastermind 28900 points
Part Number: LMX2492EVM
Other Parts Discussed in Thread: LMX2492

Hi Team,

Our customer bought LMX2492EVM but is having problem configuring the VCO frequency. According to our customer,

The EVM doesn't respond. I've already gone through the troubleshooting, didn't work.

I'm trying to change the VCO frequency, but the output stays at the same frequency the whole time. the problem is that I'm trying to change the frequency of the VCO, but somehow the spectrum is constant at 4.5GHz

in addition, when i try to set default configuration, it says - error in load default configuration SCRIPT attended to divide by zero. i'm trying to do a ramp between 9600 to 10000 MHz. 

actually, i did managed to do it, i got what i wanted, finally went to lunch and when i came back, it didn't work anymore.

I already tried to upgrade the firmware 3 times and the problem isn't solved.
Is there any steps I can do to make sure that the device is ok and not broken? I need to know so if there is one I will be able to invite another device.

Regards,

Danilo

  • 0
    TI__Guru** 108880 points

    Hi Danilo,

    Are you using the latest version TICS Pro?

    Were you able to make it lock to the default configuration?

    make sure you got green connection mode.

  • 0 in reply to Noel Fung
    TI__Mastermind 28900 points

    Hi Noel,

    According to our customer,

    I made a short video that explains my problem. I also checked everything you told me to check.
    1) I am using the latest version of TICS PRO
    2) My device isnt in lock when i press default configuration
    3) Device is connected
    Please go through the video. It has everything explained very well.
    Regards,
    Danilo
  • 0 in reply to Danilo A.
    TI__Mastermind 28560 points

    Hello Danilo,

    Thank-you for the very good videos.  I noticed on power-up the current was ~170 mA, which is what the EVM guide advises.  After programming - does this rise to 240 mA as per EVM guide?

    You mentioned the LED being low... I want to try some debug with the MUXout_MUX control to drive that LED.

    If you set the to CPMON OK, CPMON High, CPMON Low.  I expect that for one of these the output is high.. which is it?

    Can you measure the OUT R/2, Output N/2 frequencies?  This confirm what the PLL is seeing.

    73,
    Timothy

  • 0 in reply to Timothy T
    TI__Mastermind 28900 points

    Hi Timothy,

    I have forwarded your response to our customer and waiting for his feedback. I received this email from our customer earlier,

    I would like to mention that the built in VCO is not out targeted VCO and We will use CVCO55CC-2400-2569.
    So, if you suspect the problem is with the vco, let me know please because it is anyway desired to be switched.
    Also, I know that you do your best to answer as fast as you can, but I work on this project on mondays and wednesday, so please if you can answer me as fast as you can I will appreciate it a lot! 
    Regards,
    Danilo
  • 0 in reply to Danilo A.
    TI__Mastermind 28900 points

    Hi Timothy,

    Here is the customer's response.

    1) As seen from the video, after loading the current is rising to 0.210 amper. 
    2) I didn't understand what do you want me to do with the CPMON ? to switch between them and what am I expecting to see?
    3) How can i measure N/2 and R/2 ? R/2 is measured from the spectrum analyzer, isnt it?
    Regards,
    Danilo
  • 0 in reply to Danilo A.
    TI__Guru** 108880 points

    Hi Danilo,

    I watched the movies, obviously this is a TICS Pro bug. After the error message is popped up, TICS Pro is not responding to any change. For example, in part 2 of the video, the customer typed 9600 to the VCO frequency block, but the N-divider did not change to 96, it stayed at 99. 

    I can repeat this bug. workaround is close TICS Pro and then open TICS Pro again. 

    We will fix this bug in the future.

  • 0 in reply to Noel Fung
    TI__Mastermind 28900 points

    Hi Nel,

    According to our customer,

    Me and a friend of mine ordered the LMX2492EVM and his LMX worked just fine, as expected. Thus, I think the problem is with my LMX2492 and not with the TICSPRO.
    I have a super important project that is based on the LMX2492EVM, so I need your help with finding a solution. Here in Israel we have Texas Instruments representation.Here are some possible solutions that I can think of:
    1) I can go there with my device and check it there
    2) start a zoom conversation with one of your specialists and try to debug online
    3 send it to a lab to check if the problem is with the device 
    4) send me a new device.
    I need a quick solution, please answer me as soon as possible, consider it an urgent case! 
    Waiting to hear from you about a solution,
    Regards,
    Danilo
  • 0 in reply to Danilo A.
    TI__Guru** 108880 points

    Hi Danilo,

    I am pretty sure that this is a TICS Pro issue, cause I can repeat the problem (without the EVM).

    Close TICS Pro and then open it again, it will resume to normal. Now, if you change the N divider value, you can see register write activities in the status window. 

  • 0 in reply to Noel Fung
    TI__Mastermind 28900 points

    Hi Noel,

    I received this feedback from our customer,

    I already tried to close and reopen the TICS PRO, but it didn't work. Maybe I am wrong but from my experience I don't think that the problem is with the application. 
    As I mentioned before, I need you to take one step forward, to help me find a solution. I need a QUICK solution, maybe even to get a new device instead of this one. Some possible options are:
    1) I can go to Texas instruments representation in my country with my device and check it there
    2) We can start a zoom conversation with one of your specialists and try to debug online
    3 send it to a lab to check if the problem is with the device 
    4) send me a new device.
    Please give me an answer that is relevant to this message and give me a solution. We are talking and not making any progress. 
    Regards,
    Danilo
  • 0 in reply to Danilo A.
    TI__Mastermind 28560 points

    Hi Danilo,

    Danilo A. said:
    2) I didn't understand what do you want me to do with the CPMON ? to switch between them and what am I expecting to see?
    3) How can i measure N/2 and R/2 ? R/2 is measured from the spectrum analyzer, isnt it?

    The idea is to program these different values into MUXout_MUX to see what the resulting output is.  For the CPMON I expect it should be DC states, so LED readback should work.  However the best thing to do, as I would recommend for the N/2 and R/2, is to probe the MUXout pin (you could probe at LED) to see/measure with scope what the frequency is.

    On the div-0 error:

    I did see that div-0 error - and it does seem to interrupt the writing, but then later in the video, I think it appeared to write all registers, so I think that should be ok.  We do need to fix this issue however where a div 0 can occur.  Can you share the .tcb (as described below)  So we can reproduce?

    • You would need to exit TICS Pro, copy the .tcb file (as described below).
    • Start tics pro, then load defaults as you did and get the div-0 error.
      • If no div-0 error, than the .tcb file you copied was not in a state that would cause the div-0 error.

    --

    On second thought.  The div-0 interrupts the default configuration load.  This means R0 to R0x11 may be invalid.  So even pressing Ctrl+L may not result in good programming.  Please try selecting the "default" config once again.  If it still gives the error message.  You may not have all the registers and the workaround I'm giving about replacing the TCB may be the solution.  --> Please send the .tcb file.  But the fact that you re-installed and are still having issues suggests the TCB has been "replaced" already and still not working.  Is this a correct assessment?  Have you at least once got a full "load default without error", and Ctrl+L and things are still not working?

    About the TCB file:

    There is a file (.tcb) that saves the last state.  The default installed lmx2492.tcb is located in: C:\ProgramData\Texas Instruments\TICS Pro\Configurations\Devices\PLL\LMX2492.   I've attached a copy here.  By copying this attached file and over-writing the file in ProgramData (with TICS Pro not running), next time you start, you would be at 'original starting point' --> I don't know that this would solve your issue, but I'm putting it out there.  I'm thinking not because you

    One tip, to 'restart' https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/LMX2492.tcb

    73,
    Timothy

  • +1 in reply to Timothy T
    TI__Mastermind 28560 points

    Hello,

    Sounds like our debug wasn't able to resolve the issue.  We'll see what we can do about getting a replacement EVM.

    73,
    Timothy