MK3PLL: Unable to use PLL

  • Sameer Grover

    Sameer Grover - 2013-10-23

    I'm trying to get the MK3-PLL to work. I'm using an installation from the livecd. I've tested that PLL tuning works in windows and I uploaded the MK3 firmware to the DSP (and not the FPGA) using the minidebugger. Gxsm opens up but when I go to Window -> PAC controls and try to execute tune, nothing happens.

    Also, when I execute PACscope -t, the curve displayed on the screen is flat and equal to zero. The output #8 of the controller monitored on an oscilloscope is also zero.

    How can I get the PLL to work?

  • Percy Zahl

    Percy Zahl - 2013-10-26

    a) I assume you enabled the PAC control via GXSM?
    b) can you manually tune using the PAC control in GXSM?

  • Sameer Grover

    Sameer Grover - 2013-10-26


    Thanks for you reply.

    When I run, gxsm2, I get (among other things),

    HWI-DEV-MK3-I HwI SR-MK3 probing
    HWI-DEV-MK3-I03-- SR-MK3-NG 1612:0103 found -- OK, taking it.
    reading DSP magic informations and code version.
    HWI-DEV-MK3-ICPU DSP-MAGIC : 3202ee01 [M:3202ee01]
    HWI-DEV-MK3-ICPU DSP-SoftId : 00001002 [HwI:00001002]
    HWI-DEV-MK3-ICPU DSP-Version: 00003019 [HwI:00003019]
    probing succeeded: MK3 identified.
    SR-MK2/3_HwI::sranger_mk2_hwi_query:: <SRangerMK2:SPM>
    SR-MK2/3_HwI::sranger_mk2_hwi_query:: Adding DSP controls to menu
    SR-MK2/3_HwI::sranger_mk2_hwi_query:: PAC check... HwI and PLL cap. present, adding PAC control.

    I take this to mean that the PAC has been detected successfully and there are no firmware issues.

    Regarding the PAC/PLL, I first go to Windows-> SR-DSP PAC, check the PAC processing box and set the sine amplitude to 5V and frequency to 32kHz in the PAC feedback tab. Then, in the tuning tab, when I click on Execute Tune, nothing happens.
    If I run PACscope (with gxsm running) with PACscope -t, all I get is a line at zero. If I try to run PACscope in scope mode with PACscope -s, it becomes unresponsive and I have to kill it using Ctrl+C.
    Additionally, as I mentioned before the ouptut of port #8 is close to zero (as checked with an oscilloscope).

    Am I doing something wrong here?

    Also, when I start gxsm, I get a message -
    GXSM2->InstSPM Offset settings verification with DSP settings failed
    Please check and adjust:
    GXSM2 is set for Offset Adding: digital (DSP), offset outputs not used!
    MK2-A810 DSP is configured for: external/analog adding of ADC0/1_o to ADC3/4_s
    See DSP Control->Advanced Folder for DSP reconfiguration of this,
    else set Gxsm Preferences as desired.."

    How can I fix this?


  • Percy Zahl

    Percy Zahl - 2013-10-31

    The "tuning tab" in Gxsm itself is not yet functional. Only the external PAC-scope/tune tool and it only does a sweep for you.

    You may want first to see if you can do a manual tune - I mean manually step along the suspected frequency range and watch the signals. Keep both PAC feedback controllers disabled for that.

    The terminal messages are all normal.
    The warning "GXSM2->InstSPM Offset settings verification with DSP settings failed" means you do not have consistent settings on the DSP and in Gxsm at the time of startup of Gxsm. No worries. Just set the checkbox in Advanced tab ("Internal Offset Adding") in Gxsm as you need it and your are done.

    If you restart Gxsm (DO NOT REBOOT/POWER CYCLE THE DSP) -- Gxsm always reconnects to it even if Gxsm was killed or what so ever. It should be happy then.

    It does NOT touch any current DSP settings or even "abort" any eventually running job unless you ask for or change any settings. This is intentionally. With knowing what you are doing this even allowes to have multiple Gxsm instances open -- just do not do any conflicting actions at the same time...

  • Naveed Ullah

    Naveed Ullah - 2014-08-22

    I am trying a frequency sweep for quartz tuning fork crystal oscillator using GXSM to get the PLL values but can't found that feature there in GXSM 3.0.2.I will find the other parameters needed for PAC control by curve fitting in other software like IGOR Pro etc.So just want to sweep the frequency to obtained the graph between frequency and admittance or frequency vs current.see attachment

    Last edit: Naveed Ullah 2014-08-22
  • Percy Zahl

    Percy Zahl - 2014-08-22

    For this sweep and fit we now have python based tools to run parallel to gxsm for this purpose. Please also refer to the GXSM Manual , HwI MK3/A810 section, pages 176-180.

    start this tool
    gxsm-svn/plug-ins/hard/MK3-A810_spmcontrol/python_scripts$ ./

    See the big screenshot on this poster, about in the middle:


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