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TMS320F28379S: PWM Sync not working properly when Timer ISR is configured.

Rajamurugan Kaleeswaran
Prodigy 190 points
Part Number: TMS320F28379S


System details :

  I am using TMS320F28379s C2000 series micro controller and I’m trying to sync the PWM pulse between the two micro controllers considering one as a master (which sends the PWM_SYNC_OUT pulse) and another as a slave controller (i.e it receives the as PWM_SYNC_IN) - ( This is for the Inverter application)

 

  I need to sync the PWM6A & PWM6B of the Master & Slave controllers. Code configuration are as follows controller System Clock is 200MHz to generate the 20KHz (TBPRD = 5000) PWM Switching Frequency on the PWM6A & PWMB. Counter mode is in the UPDOWN counter Mode (/\/\/\/\).

 

ISSUE:

  When we configure TIMER0 ISR the PWM sync operation was affected, please see the attached image for reference. The synchronization between modules was affected for few moments randomly and getting sync again.

  • 0
    TI__Mastermind 24370 points

    Hi Rajamurugan,

    I have a few initial questions for you so I help can get some more context for your application. Just to clarify, could you please describe the desired output of the PWM signals vs. what exactly you are seeing in terms of PWM outputs, and I wanted to confirm that there is a pattern to the issue and you only see it occur during the Timer0 ISR, is that correct? Also, in what way are you trying to sync PWM modules across 2 separate microcontrollers (i.e. is there the chance of picking up noise between the two that could affect the sync signal propagation?)? Could you also please describe what is occurring in your Timer0 ISR?

    Regards,

    Allison

  • 0 in reply to Allison Nguyen
    Prodigy 190 points

    Hi Allison,

    Thanks for the reply, Whenever we configure any Timer interrupt (Timer0 or Timer1) we are facing the issue... Yes I'm trying to Sync the PWM modules across the 2 separate Micro controllers (TMS320F28379s) considering one as master and another as slave board, I've attached the code for your reference.

    8233.main.c

  • 0 in reply to Rajamurugan Kaleeswaran
    TI__Mastermind 24370 points

    Hi Rajamurugan,

    Right now it looks like your TBCLK is 200MHz, is that correct? If so, this could be causing issues in your PWM signal as it is out of spec (as per the 8.11.2.2.1 ePWM Timing Requirements table in the datasheet). You can change your dividers so that TBCLK = 100MHz instead. Please let me know if this affects the issue you are seeing.

    Regards,

    Allison