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LMX2592: how to verify without spectrum analyzer that LMX2592 registers have been programmed by USB2ANY

Pratik Tanwar
Intellectual 605 points
Part Number: LMX2592
Other Parts Discussed in Thread: USB2ANY, , TIDA-00626, LM3532EVM, LMX2492,

respected,

i have been working on reference design of TIDA-00626 which incorporates LMX2592. i have programmed the board using USB2ANY and it says it wrote some of the registers. how should i verify that the IC have been programmed. Is there any voltage level by which we can identify that LMX2592 is programmed.and it  locked in the phase.

any help will be highly appreciated

  • 0
    TI__Mastermind 28021 points
    Pratik,

    Yes. To debug and verify proper setup without spectrum analyzer, here is what I would do:

    1. Change the POWERDOWN bit on the user controls. If you can change the current consumption via serial interface, you know you are programming the device. Also, the OSCin pin has DC bias level about 1.6 V powered up and 0 V powered down.

    2. Set the lock detect pin to OUTPUT DLDMON & CP OK - this is the TICSPro setting in default mode. Then if the board is locked, a green LED should light up.

    3. You can also check the chareg pump voltage. it should be somewhere between 0.5 to Vcc -0.5 if locked.

    4. If you don't get a lock indication, a few things:
    a. Ensure you are proving a 100 MHz input. There may be an XO on teh board, but I don't think it is hooked up by default.
    b. Ensure you are not trying to lock the VCo out of it's valid tuning range.

    Regards,
    Dean
  • 0 in reply to Dean Banerjee
    Intellectual 605 points
    respected,
    i thank you for your kind reply i have some concern i request you to clear them

    1. you said to check 1.6V on OSCin pin. i am getting 1.6 V on OSCin pin ie OSCin pin of LMX2592. but through USB2ANY i am unable to power down the device. i would like to request you to help us in some of the debugging method that what should we check for if we are not able to program the LMX2592. I have tested USB2ANY on LM3532EVM and it works fine on that so i assume USB2ANY to be working perfecly. but still i am unable to program the LMX2592. how should i debug it. please help us.

    2. do the device LMX2592 gets heated up by just after powering it on for 10 mins. is the heating issue normal.

    3.the current consumption specified in TIDA-00626 is of about 750 mA but my board is consuming around 400-450 mA only is this normal.

    4. i am using the on board crystal oscillator of 100 MHz by bypassing the resistor r13 and r15. can this oscillator cause some issue in locking of the VCO.

    5. "Set the lock detect pin to OUTPUT DLDMON & CP OK - this is the TICSPro setting in default mode." i was unable to locate this kindly elaborate more on this part.

    i have done some initial testing of the board TIDA-00626. the power supply section part seems to work properly and giving appropriate ioutput. but i am unable to lock the VCO and unable to program it. kindly show us the way so that we can debug the tool and continue with our work.

    thank you so much for your time.
  • 0 in reply to Pratik Tanwar
    TI__Mastermind 28021 points
    Pratik,

    I am not familiar with TIDA_00626, but I am familar with the LMX2592, so I can't adress some of your questions, but I can say this.

    1. If you see 1.6 V, it seems like the device is powered up, but that doesn't prove it is programmed correctly. The fact that you cannot program this is an issue. To debug this:

    a. Go in the TICSPro menu to USB Communications -> Interface. Then press the "identify" button and this should blink the LED light. This validates communication between the computer and the USB2ANY
    b. Ensure the header cable is not backwards. I am not familar with this board, so I don't know how it maps.
    c. Ensure that TICSPro identifies a valid USB2ANY and is not in demo mode.

    2. I don't know the board, but if both outputs are on, then the heating ight be normal

    4. Yes. If the oscillator is not working, it will not lock. Also, for some of our devices, the programming does not work right if there is no input as this is used to clock in the bits to the registers. So I would ensure a valid reference. Also, make sure this is powered up with resistor R29 placed.

    5. I think I mixed this up with the LMX2492. For the LMX2592, go to the "User Controls Tab" by clicking on this in the upper right hand section of TICSPro. Under "General and PLL" section, ensure "MUXout" is set to "Lock Detect" and NOT "Readback. Below this, ensure that the LD_TYPE box is checked.

    Regards,
    Dean
  • 0 in reply to Dean Banerjee
    Intellectual 605 points

    respected,

     i appreciate the info provided i am still not able to power down the device using USB2ANY.

    i would like to request you to address my following doubt.

    i observed the circuit diagram of LMX2592EVM. i look at the USB2ANY interface in LMX2592EVM which is as follows.

     

    now when i compare this with the reference design i have made of TIDA-00626. which is as follows.

    my concern is that in the reference design the resistors marked as DNP why are those resistors used for. should i connect them or should i disconnect them . and if we need to connect them than why we have not done such configuration on LMX2592EVM noard. can these resistors cause any issue in programming of the board.

    kindly address my doubt

  • 0 in reply to Dean Banerjee
    Intellectual 605 points

    respected,

    following the circuit diagram and after the removal of DNP resistors i was able to lock the VCO in the initial configuration and the green led at MUXout turned up right. thank you for this support.

    i had a concern. as you said me that OSCin pin have 1.6 V powered up and must drop to ) when power down from TICSpro GUI. when i press power down initially the MUX0ut LED turns of but when i check the voltage at OSCin pin it comes around 2.6 V. i am confused as what is the issue in this. i will be testing the output on spectrum analyser soon.

    thank you

  • 0 in reply to Dean Banerjee
    Intellectual 605 points
    i would like to request some help in configuring the board for higher frequency. As provided with the default configuration which gives the output of 1.8 GHz. i was looking forward for some higher frequency. the issue lies in TICSPRO gui.

    at initial configuration the VCO gets locked properly and MUXout LED lights up but when i change the 'RF outA' in ticspro GUI to some other value the vco comes out of the locked state.

    1.kindly help me that how can i configure the LMX2592 for higher frequency and how to lock the VCO at higher frequency.
    and what should be the sequence to lock the device at any particular frequency. using the easy GUI of TICS Pro

    2. is the LMX2592 reset when the power is removed. I observed that when the VCO gets locked and output is cut off the VCO do not turn up on the a connection and we again require to program the registors.
  • 0 in reply to Pratik Tanwar
    TI__Mastermind 28021 points

    Pratik,

    1.  When you change frequency on TICSPro, it changes the muxes and frequencies.  However, you will see the "Load Registers" button turn yellow.  You can either reload the registers, or toggle the FCAL_EN.  If you do this, it should recalibrate the VCO.  If you don't the VCO won't lock.

    2.  Yes, the LMX2592 has a power on reset loses all programming when power is removed.

    REgards,
    Dean