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ADC Configuration

Question asked by Robert Richner on Oct 27, 2011
Latest reply on Mar 17, 2012 by Mark Butcher

The Kinetis documentation claims the ADC can be configured for a conversion time of 2us but the best I've seen is 72.8us. I'm using the Tower with the demo code and flipping a GPIO to measure on a scope.


        PTC_BASE_PTR->PSOR |= (1 << 3);
        ADC1_BASE_PTR->SC1[0] = ADC_SC1_ADCH(20);
        while ( (ADC1_BASE_PTR->SC1[0] & ADC_SC1_COCO_MASK) == 0 ){}  // Wait conversion end
        PTC_BASE_PTR->PCOR |= (1 << 3);


This takes 72.8us. I've searched and searched for some kind of app note regarding the ADC configuration and I can't find any. Can anyone help me with an ADC configuration to get the claimed 2us conversion? Thanks.