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/**************************************************************************/
/*!
@file Adafruit_ADS1015.cpp
@author K.Townsend (Adafruit Industries)
@license BSD (see license.txt)
Driver for the ADS1015/ADS1115 ADC
This is a library for the Adafruit MPL115A2 breakout
----> https://www.adafruit.com/products/???
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
@section HISTORY
v1.0 - First release
*/
/**************************************************************************/
#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
#include <Wire.h>
#include "Adafruit_ADS1015.h"
/**************************************************************************/
/*!
@brief Abstract away platform differences in Arduino wire library
*/
/**************************************************************************/
static uint8_t i2cread(void) {
#if ARDUINO >= 100
return Wire.read();
#else
return Wire.receive();
#endif
}
/**************************************************************************/
/*!
@brief Abstract away platform differences in Arduino wire library
*/
/**************************************************************************/
static void i2cwrite(uint8_t x) {
#if ARDUINO >= 100
Wire.write((uint8_t)x);
#else
Wire.send(x);
#endif
}
/**************************************************************************/
/*!
@brief Writes 16-bits to the specified destination register
*/
/**************************************************************************/
static void writeRegister(uint8_t i2cAddress, uint8_t reg, uint16_t value) {
Wire.beginTransmission(i2cAddress);
i2cwrite((uint8_t)reg);
i2cwrite((uint8_t)(value>>8));
i2cwrite((uint8_t)(value & 0xFF));
Wire.endTransmission();
}
/**************************************************************************/
/*!
@brief Writes 16-bits to the specified destination register
*/
/**************************************************************************/
static uint16_t readRegister(uint8_t i2cAddress, uint8_t reg) {
Wire.beginTransmission(i2cAddress);
i2cwrite(ADS1015_REG_POINTER_CONVERT);
Wire.endTransmission();
Wire.requestFrom(i2cAddress, (uint8_t)2);
return ((i2cread() << 8) | i2cread());
}
/**************************************************************************/
/*!
@brief Instantiates a new ADS1015 class w/appropriate properties
*/
/**************************************************************************/
Adafruit_ADS1015::Adafruit_ADS1015(uint8_t i2cAddress)
{
m_i2cAddress = i2cAddress;
m_conversionDelay = ADS1015_CONVERSIONDELAY;
m_bitShift = 4;
m_gain = GAIN_TWOTHIRDS; /* +/- 6.144V range (limited to VDD +0.3V max!) */
}
/**************************************************************************/
/*!
@brief Instantiates a new ADS1115 class w/appropriate properties
*/
/**************************************************************************/
Adafruit_ADS1115::Adafruit_ADS1115(uint8_t i2cAddress)
{
m_i2cAddress = i2cAddress;
m_conversionDelay = ADS1115_CONVERSIONDELAY;
m_bitShift = 0;
m_gain = GAIN_TWOTHIRDS; /* +/- 6.144V range (limited to VDD +0.3V max!) */
}
/**************************************************************************/
/*!
@brief Sets up the HW (reads coefficients values, etc.)
*/
/**************************************************************************/
void Adafruit_ADS1015::begin() {
Wire.begin();
}
/**************************************************************************/
/*!
@brief Sets the gain and input voltage range
*/
/**************************************************************************/
void Adafruit_ADS1015::setGain(adsGain_t gain)
{
m_gain = gain;
}
/**************************************************************************/
/*!
@brief Gets a gain and input voltage range
*/
/**************************************************************************/
adsGain_t Adafruit_ADS1015::getGain()
{
return m_gain;
}
/**************************************************************************/
/*!
@brief Gets a single-ended ADC reading from the specified channel
*/
/**************************************************************************/
uint16_t Adafruit_ADS1015::readADC_SingleEnded(uint8_t channel) {
if (channel > 3)
{
return 0;
}
// Start with default values
uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE | // Disable the comparator (default val)
ADS1015_REG_CONFIG_CLAT_NONLAT | // Non-latching (default val)
ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low (default val)
ADS1015_REG_CONFIG_CMODE_TRAD | // Traditional comparator (default val)
ADS1015_REG_CONFIG_DR_1600SPS | // 1600 samples per second (default)
ADS1015_REG_CONFIG_MODE_SINGLE; // Single-shot mode (default)
// Set PGA/voltage range
config |= m_gain;
// Set single-ended input channel
switch (channel)
{
case (0):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_0;
break;
case (1):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_1;
break;
case (2):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_2;
break;
case (3):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_3;
break;
}
// Set 'start single-conversion' bit
config |= ADS1015_REG_CONFIG_OS_SINGLE;
// Write config register to the ADC
writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
// Wait for the conversion to complete
delay(m_conversionDelay);
// Read the conversion results
// Shift 12-bit results right 4 bits for the ADS1015
return readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
}
/**************************************************************************/
/*!
@brief Reads the conversion results, measuring the voltage
difference between the P (AIN0) and N (AIN1) input. Generates
a signed value since the difference can be either
positive or negative.
*/
/**************************************************************************/
int16_t Adafruit_ADS1015::readADC_Differential_0_1() {
// Start with default values
uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE | // Disable the comparator (default val)
ADS1015_REG_CONFIG_CLAT_NONLAT | // Non-latching (default val)
ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low (default val)
ADS1015_REG_CONFIG_CMODE_TRAD | // Traditional comparator (default val)
ADS1015_REG_CONFIG_DR_1600SPS | // 1600 samples per second (default)
ADS1015_REG_CONFIG_MODE_SINGLE; // Single-shot mode (default)
// Set PGA/voltage range
config |= m_gain;
// Set channels
config |= ADS1015_REG_CONFIG_MUX_DIFF_0_1; // AIN0 = P, AIN1 = N
// Set 'start single-conversion' bit
config |= ADS1015_REG_CONFIG_OS_SINGLE;
// Write config register to the ADC
writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
// Wait for the conversion to complete
delay(m_conversionDelay);
// Read the conversion results
uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
if (m_bitShift == 0)
{
return (int16_t)res;
}
else
{
// Shift 12-bit results right 4 bits for the ADS1015,
// making sure we keep the sign bit intact
if (res > 0x07FF)
{
// negative number - extend the sign to 16th bit
res |= 0xF000;
}
return (int16_t)res;
}
}
/**************************************************************************/
/*!
@brief Reads the conversion results, measuring the voltage
difference between the P (AIN2) and N (AIN3) input. Generates
a signed value since the difference can be either
positive or negative.
*/
/**************************************************************************/
int16_t Adafruit_ADS1015::readADC_Differential_2_3() {
// Start with default values
uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE | // Disable the comparator (default val)
ADS1015_REG_CONFIG_CLAT_NONLAT | // Non-latching (default val)
ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low (default val)
ADS1015_REG_CONFIG_CMODE_TRAD | // Traditional comparator (default val)
ADS1015_REG_CONFIG_DR_1600SPS | // 1600 samples per second (default)
ADS1015_REG_CONFIG_MODE_SINGLE; // Single-shot mode (default)
// Set PGA/voltage range
config |= m_gain;
// Set channels
config |= ADS1015_REG_CONFIG_MUX_DIFF_2_3; // AIN2 = P, AIN3 = N
// Set 'start single-conversion' bit
config |= ADS1015_REG_CONFIG_OS_SINGLE;
// Write config register to the ADC
writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
// Wait for the conversion to complete
delay(m_conversionDelay);
// Read the conversion results
uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
if (m_bitShift == 0)
{
return (int16_t)res;
}
else
{
// Shift 12-bit results right 4 bits for the ADS1015,
// making sure we keep the sign bit intact
if (res > 0x07FF)
{
// negative number - extend the sign to 16th bit
res |= 0xF000;
}
return (int16_t)res;
}
}
/**************************************************************************/
/*!
@brief Sets up the comparator to operate in basic mode, causing the
ALERT/RDY pin to assert (go from high to low) when the ADC
value exceeds the specified threshold.
This will also set the ADC in continuous conversion mode.
*/
/**************************************************************************/
void Adafruit_ADS1015::startComparator_SingleEnded(uint8_t channel, int16_t threshold)
{
// Start with default values
uint16_t config = ADS1015_REG_CONFIG_CQUE_1CONV | // Comparator enabled and asserts on 1 match
ADS1015_REG_CONFIG_CLAT_LATCH | // Latching mode
ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low (default val)
ADS1015_REG_CONFIG_CMODE_TRAD | // Traditional comparator (default val)
ADS1015_REG_CONFIG_DR_1600SPS | // 1600 samples per second (default)
ADS1015_REG_CONFIG_MODE_CONTIN | // Continuous conversion mode
ADS1015_REG_CONFIG_MODE_CONTIN; // Continuous conversion mode
// Set PGA/voltage range
config |= m_gain;
// Set single-ended input channel
switch (channel)
{
case (0):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_0;
break;
case (1):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_1;
break;
case (2):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_2;
break;
case (3):
config |= ADS1015_REG_CONFIG_MUX_SINGLE_3;
break;
}
// Set the high threshold register
// Shift 12-bit results left 4 bits for the ADS1015
writeRegister(m_i2cAddress, ADS1015_REG_POINTER_HITHRESH, threshold << m_bitShift);
// Write config register to the ADC
writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
}
/**************************************************************************/
/*!
@brief In order to clear the comparator, we need to read the
conversion results. This function reads the last conversion
results without changing the config value.
*/
/**************************************************************************/
int16_t Adafruit_ADS1015::getLastConversionResults()
{
// Wait for the conversion to complete
delay(m_conversionDelay);
// Read the conversion results
uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
if (m_bitShift == 0)
{
return (int16_t)res;
}
else
{
// Shift 12-bit results right 4 bits for the ADS1015,
// making sure we keep the sign bit intact
if (res > 0x07FF)
{
// negative number - extend the sign to 16th bit
res |= 0xF000;
}
return (int16_t)res;
}
}