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CCS/LAUNCHXL-F28379D: SPRACO3 project questions - Dual-axis motor control using FCL on LAUNCHXL-F28379D

npaine
Intellectual 420 points
Part Number: LAUNCHXL-F28379D
Other Parts Discussed in Thread: BOOSTXL-3PHGANINV, TMDXIDDK379D

Tool/software: Code Composer Studio

Hi, I recently purchased a LAUNCHXL-F28379D + BOOSTXL-3PhGaNInv and am following the documentation (SPRACO3) for getting the FCL running on this hardware.  I have some questions about the project code.  Is this the right place to post questions on this topic?

My first question is regarding DAC outputs.  In the project there are several preprocessor macros like this:

#ifdef DACOUT_EN
//-----------------------------------------------------------------------------
// Variable display on DACs
//-----------------------------------------------------------------------------
    DAC_setShadowValue(hal.dacHandle[0],
                       DAC_MACRO_PU(motorVars[0].ptrFCL->rg.Out));
    DAC_setShadowValue(hal.dacHandle[1],
                       DAC_MACRO_PU(motorVars[0].posElecTheta));
#endif   // DACOUT_EN

DACOUT_EN is not currently defined anywhere in the source or included header files that I can find.  I can certainly define this macro somewhere in dual_axis_servo_drive.c but this feels like a hack, it seems like DACOUT_EN should already be defined in the project somewhere else.

Additionally, based on SPRACO3, its not clear where signals should be probed.  Which pins are used for DAC output?  The code is similarly ambiguous to me, its not clear which pins are being written or should be probed:

DAC_setShadowValue(hal.dacHandle[0],
                       DAC_MACRO_PU(motorVars[0].ptrFCL->rg.Out));

More generally speaking, I have found bugs in prior TI projects (specifically some pertaining to the tmdxiddk379d dev kit).  Where is the best place to submit those?

  • 0
    TI__Mastermind 27240 points

    With 3PhGaNInv booster pack, signal connection to launchpad is such that on-chip DACs could not be used, that is why you may not find the code using it.

    There are PWMs available on chip which are used as DACs by using a low pass filter. Signal frequencies below a 10th of the sampling frequency could be seen properly.

    For more info about PWMDAC details, pls review the launch pad info which is given in the user guide.

    We recommend that you review the hardware guides of both launch pad and the booster pack for better understanding.

  • 0 in reply to Ramesh Ramamoorthy
    Intellectual 420 points

    Ramesh, based on the documentation provided on page 27 of SPRACO3, it sounds like DACs A and B are supported by the 3PhGaNInv booster pack for debugging purposes:

    The documentation also talks about removing R20 for DAC monitoring purposes, which is on the DACA/B pins.  Here is the 3PhGaNInv booster pack side:

    And here's the Launch Pad side:

    This makes me think DACs A and B are intended to be used, not the PWM DACs.

    Additionally, the code seems to reference DACs A and B in dual_axis_servo_drive_hal.c line 164:

    obj->dacHandle[0] = DACA_BASE;
obj->dacHandle[1] = DACB_BASE;
obj->dacHandle[2] = DACC_BASE;

    So it seems like all of the TI documentation suggests to use the in-built DACs, but probing pins J3-10 (DACA) and J7-10 (DACB) still doesn't show any signal.

  • 0 in reply to npaine
    Intellectual 420 points

    I'm seeing another issue, I'm not reading in any current values: motorVars[0].currentAs is zero along with Bs and Cs.  The PWM signals work and I'm able to spin the motor open loop in BUILDLEVEL  = FCL_LEVEL2, but I'm not reading any currents.  It doesnt appear to be a hardware issue, a scope on ADCINCA2, B2, and C2 shows a time varying current signal.

  • 0 in reply to npaine
    Intellectual 420 points

    I found a big clue, the current measurement issue goes away when powering the system through the LaunchPAD's 3.3V power (it works when JP1-JP5 are populated on the LaunchPAD and J5 on the BoosterPack is removed).  Current measurement doesn't work when powering the 3.3V line from the BoosterPack.

  • 0 in reply to npaine
    Intellectual 420 points

    I think I found the reason that powering from the BoosterPack doesn't work. JP3 on the LaunchPad generates the 5V rail, which in turn generates the VREFHI reference which is used for the ADC reference.  This seems to be either a board design flaw or an error in the SPRACO3 documentation.

  • 0 in reply to npaine
    TI__Mastermind 27240 points

    Glad that you are able to resolve the issues. We documented the guide based on how our tests are done in lab. It is possible that certain information may be missing, that is why, it is advisable to spend some time reviewing docs and results in lower build levels. 

    If the issue is resolved, pls close the thread. 

  • 0 in reply to Ramesh Ramamoorthy
    TI__Mastermind 27240 points

    Since the issue seem to be resolved, as there are no further queries, am closing the thread. To reopen the thread, you may post within 30 days or start a new thread.