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CDCE62002EVM clock generation using GUI

ANKUR SHUKLA
Prodigy 170 points
Other Parts Discussed in Thread: CDCE62002EVM, CDCE62002

Hi ALL

I need to generate a 20 MHz clock through CDCE62002EVM. I downloaded the GUI Software.

I selected AUX as source. I used frequency planner to set the dividers  for output of 20 Mhz. I am not getting any output at YP0.

Why does  XXMHZ1 always shows a fixed frequency of 25 MHz at C85 ( I used 10 pF) even though I change frequency in GUI?

Also, in the GUI PLL lock is ON while in the EVM it is off.

Thanks and Regards

Ankur

  • 0
    TI__Mastermind 24205 points

    Hi Ankur,

    Do you have a reference frequency in mind? Can you send us your .ini file?

    Regards

    Arvind Sridhar

     

  • 0 in reply to Arvind Sridhar
    Prodigy 170 points
    Hi Arvind
    Thanks so much for the response. Can you explain me how VCO calibration works in the GUI. We just have to click /PD Calibration and we get it right?
    First I want to get output from AUX_In. I removed the crystal.Now I am getting the output. I will check output from crystal and then get back to you.
    There was some problem in VCO calibration I guess.

    Thanks and Regards
    Ankur
  • 0 in reply to ANKUR SHUKLA
    TI__Mastermind 24205 points

    Hi Ankur,

    When using the GUI, you could activate VCO calibration by clicking "/PD Calibration" button on the left side of GUI window. The behaviour of the button depends on the CALSELECT bit inside the device. Either we toggle the !PD bit (register 2, bit 7)  or PLLRESET (register 2, bit 20). The details are in the datasheet (Page 34/35). Default value of CALSELECT bit is 0.

    Also, if the input signal is not valid during self-calibration, it is necessary to re-initiate VCO calibration after the input clock signal stabilizes. Re-calibration is also necessary anytime a PLL setting is changed (e.g. divider ratios in the PLL or loop filter settings are adjusted)

    Regards

    Arvind Sridhar

  • 0 in reply to Arvind Sridhar
    Prodigy 170 points
    Hi Arvind
    Thanks for the VCO Calibration help.
    Right now I am using 20 Mhz Oscillator (535-9259-1-ND) to get an output of 20 MHz using CDCE62002 . Somehow, PLL is locking and unlocking very fast.
    PLL lock light goes on and off continuously. What could be the problem?

    It earlier worked when I provided 20 MHz signal from Clock generator to AUX_IN.

    Thanks and Regards
    Ankur
  • 0 in reply to ANKUR SHUKLA
    Prodigy 170 points
    Hi
    These are the register values in case you need to look at them.
    Register0 27FFC3A0
    Register1 FF832001
    Register2 21023932

    Thanks and Regards
    Ankur
  • 0 in reply to ANKUR SHUKLA
    TI__Mastermind 32575 points
    Please save the INI file from the GUI (includes more than just register data) and attach it to your E2E reply, so we can load your complete configuration and duplicate your scenario.

    Thanks,
    Alan