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Original question:

CCS/LAUNCHXL-F28379D: Problem with FCL_379XL PWM generation

LAUNCHXL-F28379D: LAUNCHXL-F28379D and DRV8305EVM FCL_379XL PWM Generation Problem

Abdulkadir Barak
Prodigy 40 points
Part Number: LAUNCHXL-F28379D
Other Parts Discussed in Thread: SFRA, TMS320F28379D, BOOSTXL-3PHGANINV, INA240

Tool/software:

I have a LAUNCHXL-F28379D, 2  8305evm drivers, and 2 mtrdyno motor setups. I am working with the code of the FCL_379XL project and trying to generate PWM according to level 1.  But ı didn't see anything  on the  pwm pins with the oscilloscope. 

- Set “EnableFlag” to 1 in the expressions window. The variable named “IsrTicker” will incrementally
increase as seen in expressions window confirming that the interrupt is working properly. This part is okey.IsrTicker is increasing.

EPwm1Regs.CMPA.bit.CMPA values is changing.

Motor1.svgen.Ta or Tb or TB-TC values are changing 

And also I saw a broken signal Ta like this?? 


What is the problem ı didn't understand. Do you have any idea? Please help me to generate pwm. I applied everything correctly according to this document: Dual Motor Control Using FCL and Performance Analysis
Using SFRA on TMS320F28379D LaunchPad 

  • 0
    TI__Mastermind 44146 points

    Hi,

    This design is meant to be run with the BOOSTXL-3PhGaNInv. You are adapting the software for DRV8305evm? There may be something you missed during the porting, like the GaN board provides a Fault / Over Temp signal that could be gating PWM output.

    Also BL#1 is meant to be tested without a motor connected. Maybe you can check for PWM output without the DRV board connected even.

    Best,

    Kevin

  • 0 in reply to Kevin Allen18
    Prodigy 40 points

    No I undertastand the problem. But I didn't find solution.  over current protection  occurred . 

    Even with no motor connected, all three CMPSS modules (CMPSS1, 3, and 6) immediately set the COMPHLATCH bit high. This causes TRIP4 to trigger via EPWM XBAR and shuts down the PWM outputs.

    I’ve confirmed via the watch window that COMPSTS.bit.COMPHLATCH = 1, and COMPSTS.all shows values like 770. The latches remain set even after clearing, and this happens in every loop iteration. I’m not seeing any PWM output or load connected, so real overcurrent shouldn't be the issue.

    I'm starting to suspect that the CMPINxP/N pins may be floating and picking up noise, since the current sense (e.g., INA240) is not connected yet.

    Planning to scope the CMPIN pins directly and possibly add external pull-downs.

    Has anyone seen similar behavior when CMPSS inputs are left floating?

  • +1 in reply to Abdulkadir Barak
    TI__Mastermind 44146 points

    Hi,

    Abdulkadir Barak said:
    I'm starting to suspect that the CMPINxP/N pins may be floating and picking up noise, since the current sense (e.g., INA240) is not connected yet.

    Ok, that is possible if no current sense device is driving the input signal. You could try feeding a voltage into the pin yourself then for testing.

    CMPSS has a digital filter for filtering out some noise during normal operation, I cannot remember if the example solution already uses it or not.

    Best,

    Kevin