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GPIO-triggered ADC SOC using both rising and falling edges

David DeBaun
Intellectual 405 points
Other Parts Discussed in Thread: TMS320F28075

Hello,


I'm using a TMS320F28075 and am triggering an ADC SOC using a GPIO configured as a digital input and ADCEXTSOC via Input X-Bar INPUT5. It's triggering the SOC every rising edge of the GPIO -- however, the signal on the GPIO is a square wave and I need to trigger SOCs on both the rising and falling edges. So far I haven't found a direct way of triggering an SOC based on the falling edge, too .... it seems like maybe I could route the same GPIO to the ePWM X-bar and try to sync an ePWM and somehow generate another SOC based off that PWM... but I'd rather not waste an ePWM and I'm wondering if there's a more straightforward way that I'm missing? I also just started looking at routing the Input X-Bar to the Digital Compare Submodule to see if this is something I can use for this in conjunction with the Event-Trigger submodule, instead... Any direction would be appreciated.

Thanks,

Dave

  • 0
    TI__Guru 60865 points

    Hi David,

    It looks like you can try to invert the GPIO input each time you detect a trigger.  Probably you could do this in the ISR that reads the ADC results, as long as the triggers are spaced far enough apart.  This inversion occurs before the input X-BARs, so I think it will affect the ADC external trigger.