Unverified Commit bf974ab8 authored by Birte Kristina Friesel's avatar Birte Kristina Friesel
Browse files

arduino nano adc: add getPin_mV function

parent 56dc720d

include/arch/arduino-nano/driver/adc.h

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ class AVRADC { 


		int16_t getTemp_mdegC(int16_t offset = 205);

		uint16_t getVCC_mV();

		uint16_t getPin_mV(uint8_t pin, uint16_t avcc = 0);

};



extern AVRADC adc;

src/arch/arduino-nano/driver/adc.cc

+36 −0
Original line number Diff line number Diff line
@@ -8,6 +8,42 @@ 
#include "arch.h"

#include "driver/adc.h"



uint16_t AVRADC::getPin_mV(uint8_t pin, uint16_t avcc)

{

	if (avcc) {

		// measure with AVCC reference

		ADMUX = _BV(REFS0) | pin;

	} else {

		// measure with internal 1.1V bandgap refernce

		ADMUX = _BV(REFS1) | _BV(REFS0) | pin;

	}



	// Enable ADC with /64 prescaler

	ADCSRA = _BV(ADEN) | _BV(ADPS2);



	// Wait for bandgap to stabilise (70us according to datasheet table 28-3)

	arch.delay_ms(1);



	// Start conversion

	ADCSRA |= _BV(ADSC);



	// wait until conversion is complete

	while (ADCSRA & _BV(ADSC)) ;



	uint8_t adcr_l = ADCL;

	uint8_t adcr_h = ADCH;

	uint16_t adcr = adcr_l + (adcr_h << 8);



	// Disable ADC

	ADCSRA &= ~_BV(ADEN);



	if (avcc) {

		return (uint32_t)avcc * adcr / 1023L;

	} else {

		return 1100L * adcr / 1023L;

	}

}



int16_t AVRADC::getTemp_mdegC(int16_t offset)

{

	// Measure temperature probe with 1.1V bandgap reference