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TMS320F28377D: No outputs from EPWM

Johnny Chen
Expert 5080 points
Part Number: TMS320F28377D
Other Parts Discussed in Thread: SYSCONFIG

Hi Champ,

I am asking for my customer. 

Recently, my customer is facing an issue on there is no EPWM output (EPWM5) from the pins (directly measuring both A/B channels, disconnect the part with EPWM). They have seen the failure on few pcs.  

It has been verified the EPWM configuration is ok since copy the same configuration to other sets of EPWM, there are PWM outputs from both channels. 

Besides, it is quite weird that both channels on EPWM5 can't output PWM signal, but both pins (A/B channels) are normal if they are configured to GPIO, able to set high / low. 

Customer can't do the A-B-A swap because it might damage the device when desoldering the device from PCB. 

So far, the only thing that I could think about is there might be a voltage larger than 0.3V + VDDIO on those pins or reverse current sinking from output to the pins that could damage the EPWM peripheral.

Has any expert ever seen this kind of scenario ? What might be other root cause, welcome for any suggestion ? 

Thanks and regards,

Johnny

  • 0
    TI__Genius 14205 points

    Hello Johnny,

    To clarify what you mentioned above is that you don't see Output of EPWM5A and EPWM5B on GPIO ?

    Although when you toggle GPIO by itself you can set it high or low ?

    Are you using driverlib with the help of SysConfig? If not, are you only using driverlib? if not driverlib or sysconfig, are you using bitfield support?
    Also     Can you share the code for EPWM Initialization and GPIO configuration for EPWM signals ?

  • 0 in reply to Prarthan Bhatt
    TI__Expert 5080 points

    Hi Prarthan,

    Prarthan Bhatt said:
    To clarify what you mentioned above is that you don't see Output of EPWM5A and EPWM5B on GPIO ?

    Correct. 

    Prarthan Bhatt said:
    Although when you toggle GPIO by itself you can set it high or low ?

    Correct.

    Prarthan Bhatt said:
    Are you using driverlib with the help of SysConfig? If not, are you only using driverlib? if not driverlib or sysconfig, are you using bitfield support?

    Using driverlib with Sysconfig. In order to verify this and make it simple, we are testing the code with examples from our sdk and get the signal directly from the pins, so the code configuration & initialization should be good w/o problem.

    Not sure have you seen this kind of scenario or experience before ? Except failure functionality (we can't do A-B-A swap so far), what might be root cause for that ? 

    Thanks and regards,

    Johnny

  • 0 in reply to Johnny Chen
    TI__Genius 14205 points

    Hey Johnny,

    I had no issues of seeing EPWM pulse outputs on GPIO.

    Can you double check your configuration of epwm outputs on gpio; for example configuring correct gpio pins according the mux option pins assigned in this table below :

    I have a few more questions before we start debugging your issue :

    1) Are you able to see outputs for other EPWM's ?

    2) And  if you are not able to see normal outputs on GPIO how did you conclude that you are not able to swap the outputs ?