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AM263P4-Q1: how to make sure EPWM outputs stay low during initializiation

Frank A.
Prodigy 130 points

Part Number: AM263P4-Q1
Other Parts Discussed in Thread: SYSCONFIG

Hello,

During the initialization with the sysconfig generated code, each output (A/B) of a EPWM channel (in a half-bridge configuration) will go high at some point, and finally stay like that until I turn them of by forcing a one-shot trip.

How to avoid that? 

Best regards,
Frank

  • +1
    TI__Expert 8900 points

    Hi Frank,

    What you are seeing is an initialization-sequence issue: once the pins are muxed to ePWM, the outputs can reflect the current AQ/DB/TZ state before your application has finished putting the module into its intended safe state. The ePWM driver supports both continuous software forcing of A/B low and Trip-Zone actions that force outputs to a safe level.

    To avoid the outputs going high during startup, the usual approach is to keep the ePWM outputs in a forced-safe state first (EPWM_setActionQualifierContSWForceAction(..., EPWM_AQ_SW_OUTPUT_LOW) for A/B individually).

    Or if you are already using one-shot trip, configure TZA/TZB to force the outputs low rather than relying on the PWM state.


    Best Regards,

    Masoud

  • 0 in reply to Masoud Farhadi
    Prodigy 130 points

    Calling EPWM_forceTripZoneEvent(addr, EPWM_TZ_FORCE_EVENT_OST); works, if called before Drivers_open();

    But I think it would be great if something like this could be handled with sysconfig.