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TMS320F280025: Boundary issues for EPWM

Wayne Huang
Genius 16795 points
Part Number: TMS320F280025


Dear Champs,

I am asking this for our customer.

1. When the dead band period is longer than the time point that CMPx resetting the output to low, what will the final output waveform look like?

2. When we are testing the behavior of the EPWM, we use shadow load feature, one shot global load and load at CTR=ZERO. We notice that when we set CMPA=0, the pwm output becomes low without any shadow to active load. However, when we set CMPA to any other values, again without any shadow to active load, the PWM returns to previous duty cycle before writing CMPA=0. Why CMPA=0 has such behavior and seem overriding the shadow feature?

Wayne Huang

  • 0
    TI__Guru 52040 points

    Deadband timer works independent of any other submodule. As long as the deadband is active, it will travel across period and zero boundaries and continue to modify the output.

    CMPA is not overriding the shadow feature, the actions taken have a list of priorities, and the priority list is available in the TRM. When multiple actions occur at the same time, the only action taken is the highest priority action.