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TMS320F280039C: how to use PWMA[OE] and PWMB[OE] in CLB

Aki Li
Genius 10045 points

Part Number: TMS320F280039C
Other Parts Discussed in Thread: C2000WARE

In the CLB input signals list,  it is noted that PWMA[OE] and PWMB[OE] refer to trip outputs from the respective PWM module. Is PWMA/B[OE] the output of the TZ sub-module of EPWM? If so, what is the difference from the ePWM ouput? 

I would like to use the CMPSS output as a flag for CLB input, so I was thinking the way to use the trip event(one shot) of EPWM caused by CMPSS, and need to confirm how to use PWMA/B[OE] for such usage . Highly appreciated with your feedback here. 

  • 0
    TI__Mastermind 21561 points

    Hi Aki,

    The PWM[OE] signals refer to output enable for the IO buffer, and it can be used if you want to tristate the CLB output. If I recall, there is an EPWMx OST signal located on the local input bus that can be used to trigger the CLB upon an ePWM trip. This is on the local bus so keep in mind that CLB1 can only use the OST signal from ePWM1, CLB2 can only use the OST signal from ePWM2, etc.

    CLB example 29 within the C2000Ware also shows an example of a trip zone being used as a trigger for the CLB. In that example, though, an AUXSIG is used to connect the CLB input to the same GPIO that gets tripped by the ePWM module.

    Please reach out if you have additional questions.

    Regards,

    Peter

  • 0 in reply to Peter Luong
    TI__Genius 10045 points

    Hi Peter,

    Thank you for the explanation. It is difficult for users to understand  "trip output" in the TRM represents the tristate of EPWMx output. Actually, I still don't understand what the use case for this signal in the actual application. Could you please help further take an example to explain? 

    The OST signal could work, but it is limited to the dedicated CLB tiles. 

    Thank you.

  • 0 in reply to Aki Li
    TI__Guru 52070 points
    Peter Luong said:
    The PWM[OE] signals refer to output enable for the IO buffer, and it can be used if you want to tristate the CLB output

    Peter is correct. The OUTPUT ENABLE (OE) allows you to disable or enable the EPWM outputs. Like a FINAL ON/OFF switch.

  • 0 in reply to Nima Eskandari
    TI__Genius 10045 points

    Hi Nima,

    Nima Eskandari said:
    The OUTPUT ENABLE (OE) allows you to disable or enable the EPWM outputs. Like a FINAL ON/OFF switch.

    It might be difficult to understand since PWM[OE] is the input signal for CLB. Still not clear how to use it in the real case. 

  • 0 in reply to Aki Li
    TI__Guru 52070 points

    You should be able to check to see if the output is enabled or not

      can you comment on the original usecase of adding EPWM OE to the CLB input mux?

  • 0 in reply to Nima Eskandari
    TI__Mastermind 24095 points

    OE control is mainly intended to implement trip function using CLB.
    For example, if you have to tristate the PWM output - it can only be done via EPWM OE.