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Original question:

TMS320F280049: Race condition when EPWM shadow to active load and action qualifier both at TBCTR = PRD

TMS320F280049: Race condition for TBPHS and CMPA value load at the same time and AQ has work to do at CMPA counter up

Sheldon He
Expert 8585 points
Part Number: TMS320F280049

Hi expert,

My customer would like to know what will happen in below PWM configurations.

1. PWM counter in up count mode, CMPA is in immediate load mode

3. CMPA value and TBPHS value are loaded at the exact same time with the exact same value

2. AQ settings: CAU to toggle the PWM output

Will PWM miss the AQ action at this circumstance? Do you have any advice on this kind of application?

Thanks

Sheldon

  • 0
    TI__Mastermind 24095 points

    Sheldon,

    Sheldon He said:
    CMPA value and TBPHS value are loaded at the exact same time with the exact same value


    These are 2 asynchronous events - CPU loading the CMPA value in immediate mode and a Sync event loading the TBPHS value in to the Time base counter.
    If indeed the CMPA value is updated by the time TBPHS is loaded in to the counter - then the CMP event will have effect. 

    But I would suggest that you avoid such boundary conditions, particularly because you are dealing with the immediate mode of operation.