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