Analog2Digital.h File Reference

This file provides functions that access the analog-to-digital conversion capability of the ATmega328 and ATmega2560 microcontrollers. More...

#include <stdint.h>
#include "GpioPinMacros.h"

Include dependency graph for Analog2Digital.h:

Go to the source code of this file.

Macros
#define	readGpioPinAnalog(pinName)
	Read the analog value of the pin.

Enumerations
enum	A2DVoltageReference { kA2dReferenceAREF , kA2dReferenceAVCC , kA2dReference11V , kA2dReference256V }
	Constants representing voltage references. More...

Functions
int	readA2D (int8_t channel)
	Read an analog voltage value.
uint16_t	readGpioPinAnalogV (const GpioPinVariable &pinVar)
	Read the analog value of the pin.
void	initA2D (uint8_t ref=kA2dReferenceAVCC)
	Initialize the analog-to-digital system.
void	turnOffA2D ()
	Turn off the analog-to-digital system.
void	setA2DVoltageReference (A2DVoltageReference ref)
	Set the voltage reference for the analog-to-digital system.
void	setA2DVoltageReferenceAREF ()
	Set the voltage reference for the analog-to-digital system to AREF.
void	setA2DVoltageReferenceAVCC ()
	Set the voltage reference for the analog-to-digital system to AREF.
void	setA2DVoltageReference11V ()
	Set the voltage reference for the analog-to-digital system to AREF.
void	setA2DVoltageReference256V ()
	Set the voltage reference for the analog-to-digital system to AREF.

Detailed Description

This file provides functions that access the analog-to-digital conversion capability of the ATmega328 and ATmega2560 microcontrollers.

To use these functions, include Analog2Digital.h in your source code and link against Analog2Digital.cpp.

Macro Definition Documentation

readGpioPinAnalog

#define readGpioPinAnalog

(

pinName

)

Read the analog value of the pin.

This function returns a number between 0 and 1023 that corresponds to voltage between 0 and a maximum reference value. The reference value is set using one of the setA2DVoltageReferenceXXX() functions.

• pinName a pin name macro generated by GpioPinAnalog().

Returns

an value between 0 and 1023.

Note

Before calling this function must fist initialize the analog-to-digital sub-system by calling initA2D().

Enumeration Type Documentation

A2DVoltageReference

enum A2DVoltageReference

Constants representing voltage references.

Enumerator
kA2dReferenceAREF	Reference is AREF pin, internal VREF turned off.
kA2dReferenceAVCC	Reference is AVCC pin, internal VREF turned off.
kA2dReference11V	Reference is internal 1.1V VREF.
kA2dReference256V	Reference is internal 2.56V VREF (only available on ATmega2560)

Function Documentation

initA2D()

void initA2D

(

uint8_t

ref = kA2dReferenceAVCC

)

Initialize the analog-to-digital system.

You must call this function before using any of the analog-to-digital functions.

• ref provides the voltage reference to be used for analog-to-digital conversions. Pass one of the constants from enum A2DVoltageReference. If no value is provided, the default is kA2dReferenceAVCC.

Note

This function only works for CPU clocks running at either 8 MHz, 12 MHz, or 16 MHz.

readA2D()

int readA2D

(

int8_t

channel

)

Read an analog voltage value.

Voltage is read relative to the currently set reference value.

• channel is an ADC channel number (between 0 and 7 on ATmega328; between 0 and 15 on ATMega2560).

Returns

a number between 0 and 1023.

Note

Generally users will not call this function but instead call readPinAnalog() passing it a pin name macro generated by Analog().

readGpioPinAnalogV()

uint16_t readGpioPinAnalogV ( const GpioPinVariable &  pinVar )

inline

Read the analog value of the pin.

This function returns a number between 0 and 1023 that corresponds to voltage between 0 and a maximum reference value. The reference value is set using one of the setA2DVoltageReferenceXXX() functions.

• pinVar a pin variable that has analog-to-digital capabilities (i.e., initialized with makeGpioVarFromGpioPinAnalog()).

Returns

an value between 0 and 1023.

Note

Before calling this function must fist initialize the analog-to-digital sub-system by calling initA2D().

setA2DVoltageReference()

void setA2DVoltageReference

(

A2DVoltageReference

ref

)

Set the voltage reference for the analog-to-digital system.

After your have initialized the analog-to-digital system with initA2D(), you can use this function to change the voltage reference.

• ref provides the voltage reference to be used for analog-to-digital conversions. Pass one of the constants from enum A2DVoltageReference.

setA2DVoltageReference11V()

void setA2DVoltageReference11V ( )

inline

Set the voltage reference for the analog-to-digital system to AREF.

This is an inline synonym for setA2DVoltageReference( kA2dReference11V )

setA2DVoltageReference256V()

void setA2DVoltageReference256V ( )

inline

Set the voltage reference for the analog-to-digital system to AREF.

This is an inline synonym for setA2DVoltageReference( kA2dReference256V )

Note

this function is only available on ATmega2560 (not on the ATmega328).

setA2DVoltageReferenceAREF()

void setA2DVoltageReferenceAREF ( )

inline

Set the voltage reference for the analog-to-digital system to AREF.

This is an inline synonym for setA2DVoltageReference( kA2dReferenceAREF )

setA2DVoltageReferenceAVCC()

void setA2DVoltageReferenceAVCC ( )

inline

Set the voltage reference for the analog-to-digital system to AREF.

This is an inline synonym for setA2DVoltageReference( kA2dReferenceAVCC )