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Tivaware weak pull down and ADC?


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#1 Davidwallis

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Posted 09 January 2017 - 07:34 PM

Is it possible to configure a weak Down up on an adc? 

 

I have tried this but it doesn't seem to work..(based on the single ended adc example, comments removed for clarity.. 

 

 
SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
 
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
 
GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_3);
 
 //Configure Weak pull down
 GPIOPadConfigSet(GPIO_PORTE_BASE,GPIO_PIN_3,GPIO_STRENGTH_2MA,GPIO_PIN_TYPE_STD_WPD);
 
 ADCSequenceConfigure(ADC0_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
 
ADCSequenceStepConfigure(ADC0_BASE, 3, 0, ADC_CTL_CH0 | ADC_CTL_IE | ADC_CTL_END);
 
ADCSequenceEnable(ADC0_BASE, 3);
 
ADCIntClear(ADC0_BASE, 3);
 
Thanks
 

 



#2 dubnet

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Posted 09 January 2017 - 09:37 PM

My guess is that it would only apply to the pin when configured as digital I/O.  Given these aren't likely laser trimmed resistors with low temperature coefficients, they would likely add error to the A/D result.

 

Just an educated guess. Perhaps someone more knowledgeable can jump in to confirm. 






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