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Original question:

CCS/TMS320F280049M: which the TZ signal works to shut down the PWM

how to tell which TZ pin tripped an ePWM TZ

hua qian
Prodigy 50 points


Hi,

 I'm using TRIP ZONE of DSP 28335. I connect all 6 TZ signals(TZ1,TZ2...TZ6) to every 6 epwm modules(because I need to output 12 pwm). So, in my case, when  an ePWM TZ is tripped,how to tell which TZ pin or pins tripped this epwm tz?

thanks a lot!

  • 0
    TI__Guru 57255 points

    Hi,

    For the F2833x family, there isn't a method to determine which TZ event caused the trip within the ePWM peripheral.

    My best recommendation would be the following: 
    If you're not using the 3 external interrupt (XINT) features, you could use their flags to help determine 3 trip sources (configured to trigger on a falling edge input & configured to be looking at some of the same GPIOs as the TZs). 

    However, the other three TZs wouldn't be able to be determined  (since there are only 3 total).  Depending on your application, this may be adequate though.

    ===

    Other options may include routing the signal going to the TZ pin on the device to also get routed to a second GPIO pin, one that could be configured as something that could create an interrupt on an edge - for example, an eCAP.  This is largely only an option if you haven't layed out your board though.

    Another option could be to do something like I suggested in the below, but it doesn't look like you have spare ePWM peripherals:
    https://e2e.ti.com/support/microcontrollers/c2000/f/171/p/114741/407475#407475

    FYI: On newer devices, this challenge isn't completely solved - but there are other potential methods that can be used.

    Hopefully this helps!


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Intellectual 860 points

    Brett,

    Couldn't you use XINTs for all of the TZs? In the user guide, it looks like all TZs come from the GPIO mux on this device (EMUSTOP, CLOCKFAIL, EQEPERR internal signals from newer devices don't seem to be an option). Looks like there are 7 XINTs available as well.

    Regards,

    Kris

  • 0 in reply to Kris Parrent
    TI__Guru 57255 points

    It appears you are correct, Kris.  I forgot that there were more than 3 external interrupt features on this specific device.

    -Brett

  • 0 in reply to Brett Larimore
    Prodigy 50 points
    Thanks everyone! I think I have to use an extral CPLD to work with DSP28335.