commit aef37c6fe887cd91d0c22484a1671511a6dd4c46
Author: willem <willem@oldemans.nl>
Date:   Sun Nov 28 12:03:26 2021 +0100

    fork from github

diff --git a/.arduino-ci.yml b/.arduino-ci.yml
new file mode 100644
index 0000000..e7cb463
--- /dev/null
+++ b/.arduino-ci.yml
@@ -0,0 +1,11 @@
+compile:
+  # Choosing to run compilation tests on 2 different Arduino platforms
+  platforms:
+    - uno
+    # - due
+    # - zero
+    # - leonardo
+    - m4
+    - esp32
+    # - esp8266
+    # - mega2560
\ No newline at end of file
diff --git a/.github/workflows/arduino-lint.yml b/.github/workflows/arduino-lint.yml
new file mode 100644
index 0000000..b2ca058
--- /dev/null
+++ b/.github/workflows/arduino-lint.yml
@@ -0,0 +1,13 @@
+
+name: Arduino-lint
+
+on: [push, pull_request]
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: arduino/arduino-lint-action@v1
+        with:
+          library-manager: update
+          compliance: strict
diff --git a/.github/workflows/arduino_test_runner.yml b/.github/workflows/arduino_test_runner.yml
new file mode 100644
index 0000000..096b975
--- /dev/null
+++ b/.github/workflows/arduino_test_runner.yml
@@ -0,0 +1,17 @@
+---
+name: Arduino CI
+
+on: [push, pull_request]
+
+jobs:
+  runTest:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.6
+      - run: |
+          gem install arduino_ci
+          arduino_ci.rb
diff --git a/.github/workflows/jsoncheck.yml b/.github/workflows/jsoncheck.yml
new file mode 100644
index 0000000..04603d0
--- /dev/null
+++ b/.github/workflows/jsoncheck.yml
@@ -0,0 +1,18 @@
+name: JSON check
+
+on:
+  push:
+    paths:
+      - '**.json'
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: json-syntax-check
+        uses: limitusus/json-syntax-check@v1
+        with:
+          pattern: "\\.json$"
+
diff --git a/ADS1X15.cpp b/ADS1X15.cpp
new file mode 100644
index 0000000..4960cab
--- /dev/null
+++ b/ADS1X15.cpp
@@ -0,0 +1,636 @@
+//
+//    FILE: ADS1X15.cpp
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.3.3
+//    DATE: 2013-03-24
+// PUPROSE: Arduino library for ADS1015 and ADS1115
+//     URL: https://github.com/RobTillaart/ADS1X15
+//
+//  HISTORY:
+//  0.0.0   2013-03-24  initial version
+//  0.0.1   2013-03-24  first working version
+//  0.1.0   2017-07-31  removed pre 1.0 support; added getVoltage
+//  0.2.0   2020-04-08  initial release; refactor ad fundum;
+//  0.2.1   2020-08-15  fix issue 2 gain; refactor
+//  0.2.2   2020-08-18  add begin(sda, scl) for ESP32
+//  0.2.3   2020-08-20  add comparator code + async mode
+//  0.2.4   2020-08-26  check readme.md  and minor fixes
+//  0.2.5   2020-08-26  add missing readADC_Differential_X_X()
+//  0.2.6   2020-09-01  fix #12 - fix getMaxVoltage + minor refactor
+//  0.2.7   2020-09-27  redo readRegister() + getValue() + getError()
+//  0.3.0   2021-03-29  add Wire parameter to constructors.
+//  0.3.1   2021-04-25  #22, add get/setClock() for Wire speed + reset()
+//  0.3.2   2021-10-07  fix build-CI; update readme + add new examples
+//  0.3.3   2021-10-17  update build-CI (esp32), readme.md, keywords.txt
+
+
+#include "ADS1X15.h"
+
+#define ADS1015_CONVERSION_DELAY    1
+#define ADS1115_CONVERSION_DELAY    8
+
+
+// Kept #defines a bit in line with Adafruit library.
+
+// REGISTERS
+#define ADS1X15_REG_CONVERT         0x00
+#define ADS1X15_REG_CONFIG          0x01
+#define ADS1X15_REG_LOW_THRESHOLD   0x02
+#define ADS1X15_REG_HIGH_THRESHOLD  0x03
+
+
+// CONFIG REGISTER
+
+// BIT 15       Operational Status         // 1 << 15
+#define ADS1X15_OS_BUSY             0x0000
+#define ADS1X15_OS_NOT_BUSY         0x8000
+#define ADS1X15_OS_START_SINGLE     0x8000
+
+// BIT 12-14    read differential
+#define ADS1X15_MUX_DIFF_0_1        0x0000
+#define ADS1X15_MUX_DIFF_0_3        0x1000
+#define ADS1X15_MUX_DIFF_1_3        0x2000
+#define ADS1X15_MUX_DIFF_2_3        0x3000
+//              read single
+#define ADS1X15_READ_0              0x4000  // pin << 12
+#define ADS1X15_READ_1              0x5000  // pin = 0..3
+#define ADS1X15_READ_2              0x6000
+#define ADS1X15_READ_3              0x7000
+
+
+// BIT 9-11     gain                        // (0..5) << 9
+#define ADS1X15_PGA_6_144V          0x0000  // voltage
+#define ADS1X15_PGA_4_096V          0x0200  //
+#define ADS1X15_PGA_2_048V          0x0400  // default
+#define ADS1X15_PGA_1_024V          0x0600
+#define ADS1X15_PGA_0_512V          0x0800
+#define ADS1X15_PGA_0_256V          0x0A00
+
+// BIT 8        mode                        // 1 << 8
+#define ADS1X15_MODE_CONTINUE       0x0000
+#define ADS1X15_MODE_SINGLE         0x0100
+
+// BIT 5-7      data rate sample per second  // (0..7) << 5
+/*
+differs for different devices, check datasheet or readme.md
+
+| data rate | ADS101x | ADS 111x | Notes   |
+|:---------:|--------:|---------:|:-------:|
+|     0     |   128   |   8      | slowest |
+|     1     |   250   |   16     |         |
+|     2     |   490   |   32     |         |
+|     3     |   920   |   64     |         |
+|     4     |   1600  |   128    | default |
+|     5     |   2400  |   250    |         |
+|     6     |   3300  |   475    |         |
+|     7     |   3300  |   860    | fastest |
+*/
+
+// BIT 4 comparator modi                    // 1 << 4
+#define ADS1X15_COMP_MODE_TRADITIONAL   0x0000
+#define ADS1X15_COMP_MODE_WINDOW        0x0010
+
+// BIT 3 ALERT active value                 // 1 << 3
+#define ADS1X15_COMP_POL_ACTIV_LOW      0x0000
+#define ADS1X15_COMP_POL_ACTIV_HIGH     0x0008
+
+// BIT 2 ALERT latching                     // 1 << 2
+#define ADS1X15_COMP_NON_LATCH          0x0000
+#define ADS1X15_COMP_LATCH              0x0004
+
+// BIT 0-1 ALERT mode                       // (0..3)
+#define ADS1X15_COMP_QUE_1_CONV         0x0000  // trigger alert after 1 convert
+#define ADS1X15_COMP_QUE_2_CONV         0x0001  // trigger alert after 2 converts
+#define ADS1X15_COMP_QUE_4_CONV         0x0002  // trigger alert after 4 converts
+#define ADS1X15_COMP_QUE_NONE           0x0003  // dosable comparator
+
+
+// _CONFIG masks
+//
+// | bit  | description          |
+// |:----:|:---------------------|
+// |  0   | # channels           |
+// |  1   | -                    |
+// |  2   | resolution           |
+// |  3   | -                    |
+// |  4   | GAIN supported       |
+// |  5   | COMPARATOR supported |
+// |  6   | -                    |
+// |  7   | -                    |
+//
+#define ADS_CONF_CHAN_1  0x00
+#define ADS_CONF_CHAN_4  0x01
+#define ADS_CONF_RES_12  0x00
+#define ADS_CONF_RES_16  0x04
+#define ADS_CONF_NOGAIN  0x00
+#define ADS_CONF_GAIN    0x10
+#define ADS_CONF_NOCOMP  0x00
+#define ADS_CONF_COMP    0x20
+
+
+//////////////////////////////////////////////////////
+//
+// BASE CONSTRUCTOR
+//
+ADS1X15::ADS1X15()
+{
+  reset();
+}
+
+
+//////////////////////////////////////////////////////
+//
+// PUBLIC
+//
+void ADS1X15::reset()
+{
+  setGain(0);      // _gain = ADS1X15_PGA_6_144V;
+  setMode(1);      // _mode = ADS1X15_MODE_SINGLE;
+  setDataRate(4);  // middle speed, depends on device.
+
+  // COMPARATOR variables   # see notes .h
+  _compMode       = 0;
+  _compPol        = 1;
+  _compLatch      = 0;
+  _compQueConvert = 3;
+}
+
+
+#if defined (ESP8266) || defined(ESP32)
+bool ADS1X15::begin(uint8_t sda, uint8_t scl)
+{
+  _wire = &Wire;
+  _wire->begin(sda, scl);
+  if ((_address < 0x48) || (_address > 0x4B)) return false;
+  if (! isConnected()) return false;
+  return true;
+}
+#endif
+
+
+bool ADS1X15::begin()
+{
+  _wire->begin();
+  if ((_address < 0x48) || (_address > 0x4B)) return false;
+  if (! isConnected()) return false;
+  return true;
+}
+
+
+bool ADS1X15::isBusy()
+{
+  return isReady() == false;
+}
+
+
+bool ADS1X15::isReady()
+{
+  uint16_t val = _readRegister(_address, ADS1X15_REG_CONFIG);
+  return ((val & ADS1X15_OS_NOT_BUSY) > 0);
+}
+
+
+bool ADS1X15::isConnected()
+{
+  _wire->beginTransmission(_address);
+  return (_wire->endTransmission() == 0);
+}
+
+
+void ADS1X15::setGain(uint8_t gain)
+{
+  if (!(_config & ADS_CONF_GAIN)) gain = 0;
+  switch (gain)
+  {
+    default:  // catch invalid values and go for the safest gain.
+    case 0:  _gain = ADS1X15_PGA_6_144V;  break;
+    case 1:  _gain = ADS1X15_PGA_4_096V;  break;
+    case 2:  _gain = ADS1X15_PGA_2_048V;  break;
+    case 4:  _gain = ADS1X15_PGA_1_024V;  break;
+    case 8:  _gain = ADS1X15_PGA_0_512V;  break;
+    case 16: _gain = ADS1X15_PGA_0_256V;  break;
+  }
+}
+
+
+uint8_t ADS1X15::getGain()
+{
+  if (!(_config & ADS_CONF_GAIN)) return 0;
+  switch (_gain)
+  {
+    case ADS1X15_PGA_6_144V: return 0;
+    case ADS1X15_PGA_4_096V: return 1;
+    case ADS1X15_PGA_2_048V: return 2;
+    case ADS1X15_PGA_1_024V: return 4;
+    case ADS1X15_PGA_0_512V: return 8;
+    case ADS1X15_PGA_0_256V: return 16;
+  }
+  _err = ADS1X15_INVALID_GAIN;
+  return _err;
+}
+
+
+float ADS1X15::toVoltage(int16_t val)
+{
+  if (val == 0) return 0;
+
+  float volts = getMaxVoltage();
+  if (volts < 0) return volts;
+
+  volts *= val;
+  if (_config & ADS_CONF_RES_16)
+  {
+    volts /= 32767;  // val = 16 bits - sign bit = 15 bits mantissa
+  }
+  else
+  {
+    volts /= 2047;   // val = 12 bits - sign bit = 11 bit mantissa
+  }
+  return volts;
+}
+
+
+float ADS1X15::getMaxVoltage()
+{
+  switch (_gain)
+  {
+    case ADS1X15_PGA_6_144V: return 6.144;
+    case ADS1X15_PGA_4_096V: return 4.096;
+    case ADS1X15_PGA_2_048V: return 2.048;
+    case ADS1X15_PGA_1_024V: return 1.024;
+    case ADS1X15_PGA_0_512V: return 0.512;
+    case ADS1X15_PGA_0_256V: return 0.256;
+  }
+  _err = ADS1X15_INVALID_VOLTAGE;
+  return _err;
+}
+
+
+void ADS1X15::setMode(uint8_t mode)
+{
+  switch (mode)
+  {
+    case 0: _mode = ADS1X15_MODE_CONTINUE; break;
+    default:
+    case 1: _mode = ADS1X15_MODE_SINGLE;   break;
+  }
+}
+
+
+uint8_t ADS1X15::getMode(void)
+{
+  switch (_mode)
+  {
+    case ADS1X15_MODE_CONTINUE: return 0;
+    case ADS1X15_MODE_SINGLE:   return 1;
+  }
+  _err = ADS1X15_INVALID_MODE;
+  return _err;
+}
+
+
+void ADS1X15::setDataRate(uint8_t dataRate)
+{
+  _datarate = dataRate;
+  if (_datarate > 7) _datarate = 4;  // default
+  _datarate <<= 5;      // convert 0..7 to mask needed.
+}
+
+
+uint8_t ADS1X15::getDataRate(void)
+{
+  return (_datarate >> 5) & 0x07;  // convert mask back to 0..7
+}
+
+
+int16_t ADS1X15::readADC(uint8_t pin)
+{
+  if (pin >= _maxPorts) return 0;
+  uint16_t mode = ((4 + pin) << 12); // pin to mask
+  return _readADC(mode);
+}
+
+
+void  ADS1X15::requestADC_Differential_0_1()
+{
+  _requestADC(ADS1X15_MUX_DIFF_0_1);
+}
+
+
+int16_t ADS1X15::readADC_Differential_0_1()
+{
+  return _readADC(ADS1X15_MUX_DIFF_0_1);
+}
+
+
+void ADS1X15::requestADC(uint8_t pin)
+{
+  if (pin >= _maxPorts) return;
+  uint16_t mode = ((4 + pin) << 12);   // pin to mask
+  _requestADC(mode);
+}
+
+
+int16_t ADS1X15::getValue()
+{
+  int16_t raw = _readRegister(_address, ADS1X15_REG_CONVERT);
+  if (_bitShift) raw >>= _bitShift;  // Shift 12-bit results
+  return raw;
+}
+
+
+void ADS1X15::setComparatorThresholdLow(int16_t lo)
+{
+  _writeRegister(_address, ADS1X15_REG_LOW_THRESHOLD, lo);
+};
+
+
+int16_t ADS1X15::getComparatorThresholdLow()
+{
+  return _readRegister(_address, ADS1X15_REG_LOW_THRESHOLD);
+};
+
+
+void ADS1X15::setComparatorThresholdHigh(int16_t hi)
+{
+  _writeRegister(_address, ADS1X15_REG_HIGH_THRESHOLD, hi);
+};
+
+
+int16_t ADS1X15::getComparatorThresholdHigh()
+{
+  return _readRegister(_address, ADS1X15_REG_HIGH_THRESHOLD);
+};
+
+
+int8_t ADS1X15::getError()
+{
+  int8_t rv = _err;
+  _err = ADS1X15_OK;
+  return rv;
+}
+
+
+void ADS1X15::setWireClock(uint32_t clockSpeed)
+{
+  _clockSpeed = clockSpeed;
+  _wire->setClock(_clockSpeed);
+}
+
+
+// TODO: get the real clock speed from the I2C interface if possible.
+// ESP ==> ??
+uint32_t ADS1X15::getWireClock()
+{
+#if defined(__AVR__)
+  uint32_t speed = F_CPU / ((TWBR * 2) + 16);
+  return speed;
+
+#elif defined(ESP32)
+  return (uint32_t) _wire->getClock();
+
+// #elif defined(ESP8266)
+// core_esp8266_si2c.cpp holds the data see => void Twi::setClock(
+// not supported.
+// return -1;
+
+#else  // best effort ...
+  return _clockSpeed;
+#endif
+}
+
+
+//////////////////////////////////////////////////////
+//
+// PROTECTED
+//
+int16_t ADS1X15::_readADC(uint16_t readmode)
+{
+  _requestADC(readmode);
+  if (_mode == ADS1X15_MODE_SINGLE)
+  {
+    while ( isBusy() ) yield();   // wait for conversion; yield for ESP.
+  }
+  else
+  {
+    delay(_conversionDelay);      // TODO needed in continuous mode?
+  }
+  return getValue();
+}
+
+void ADS1X15::_requestADC(uint16_t readmode)
+{
+  // write to register is needed in continuous mode as other flags can be changed
+  uint16_t config = ADS1X15_OS_START_SINGLE;  // bit 15     force wake up if needed
+  config |= readmode;                         // bit 12-14
+  config |= _gain;                            // bit 9-11
+  config |= _mode;                            // bit 8
+  config |= _datarate;                        // bit 5-7
+  if (_compMode)  config |= ADS1X15_COMP_MODE_WINDOW;         // bit 4      comparator modi
+  else            config |= ADS1X15_COMP_MODE_TRADITIONAL;
+  if (_compPol)   config |= ADS1X15_COMP_POL_ACTIV_HIGH;      // bit 3      ALERT active value
+  else            config |= ADS1X15_COMP_POL_ACTIV_LOW;
+  if (_compLatch) config |= ADS1X15_COMP_LATCH;
+  else            config |= ADS1X15_COMP_NON_LATCH;           // bit 2      ALERT latching
+  config |= _compQueConvert;                                  // bit 0..1   ALERT mode
+  _writeRegister(_address, ADS1X15_REG_CONFIG, config);
+}
+
+bool ADS1X15::_writeRegister(uint8_t address, uint8_t reg, uint16_t value)
+{
+  _wire->beginTransmission(address);
+  _wire->write((uint8_t)reg);
+  _wire->write((uint8_t)(value >> 8));
+  _wire->write((uint8_t)(value & 0xFF));
+  return (_wire->endTransmission() == 0);
+}
+
+uint16_t ADS1X15::_readRegister(uint8_t address, uint8_t reg)
+{
+  _wire->beginTransmission(address);
+  _wire->write(reg);
+  _wire->endTransmission();
+
+  int rv = _wire->requestFrom(address, (uint8_t) 2);
+  if (rv == 2)
+  {
+    uint16_t value = _wire->read() << 8;
+    value += _wire->read();
+    return value;
+  }
+  return 0x0000;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// ADS1013
+//
+ADS1013::ADS1013(uint8_t address, TwoWire *wire)
+{
+  _address = address;
+  _wire = wire;
+  _config = ADS_CONF_NOCOMP | ADS_CONF_NOGAIN | ADS_CONF_RES_12 | ADS_CONF_CHAN_1;
+  _conversionDelay = ADS1015_CONVERSION_DELAY;
+  _bitShift = 4;
+  _maxPorts = 1;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// ADS1014
+//
+ADS1014::ADS1014(uint8_t address, TwoWire *wire)
+{
+  _address = address;
+  _wire = wire;
+  _config = ADS_CONF_COMP | ADS_CONF_GAIN | ADS_CONF_RES_12 | ADS_CONF_CHAN_1;
+  _conversionDelay = ADS1015_CONVERSION_DELAY;
+  _bitShift = 4;
+  _maxPorts = 1;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// ADS1015
+//
+ADS1015::ADS1015(uint8_t address, TwoWire *wire)
+{
+  _address = address;
+  _wire = wire;
+  _config = ADS_CONF_COMP | ADS_CONF_GAIN | ADS_CONF_RES_12 | ADS_CONF_CHAN_4;
+  _conversionDelay = ADS1015_CONVERSION_DELAY;
+  _bitShift = 4;
+  _maxPorts = 4;
+}
+
+int16_t ADS1015::readADC_Differential_0_3()
+{
+  return _readADC(ADS1X15_MUX_DIFF_0_3);
+}
+
+int16_t ADS1015::readADC_Differential_1_3()
+{
+  return _readADC(ADS1X15_MUX_DIFF_1_3);
+}
+
+int16_t ADS1015::readADC_Differential_2_3()
+{
+  return _readADC(ADS1X15_MUX_DIFF_2_3);
+}
+
+int16_t ADS1015::readADC_Differential_0_2()
+{
+  return readADC(2) - readADC(0);
+}
+
+int16_t ADS1015::readADC_Differential_1_2()
+{
+  return readADC(2) - readADC(1);;
+}
+
+
+
+void ADS1015::requestADC_Differential_0_3()
+{
+  _requestADC(ADS1X15_MUX_DIFF_0_3);
+}
+
+void ADS1015::requestADC_Differential_1_3()
+{
+  _requestADC(ADS1X15_MUX_DIFF_1_3);
+}
+
+void ADS1015::requestADC_Differential_2_3()
+{
+  _requestADC(ADS1X15_MUX_DIFF_2_3);
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// ADS1113
+//
+ADS1113::ADS1113(uint8_t address, TwoWire *wire)
+{
+  _address = address;
+  _wire = wire;
+  _config = ADS_CONF_NOCOMP | ADS_CONF_NOGAIN | ADS_CONF_RES_16 | ADS_CONF_CHAN_1;
+  _conversionDelay = ADS1115_CONVERSION_DELAY;
+  _bitShift = 0;
+  _maxPorts = 1;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// ADS1114
+//
+ADS1114::ADS1114(uint8_t address, TwoWire *wire)
+{
+  _address = address;
+  _wire = wire;
+  _config = ADS_CONF_COMP | ADS_CONF_GAIN | ADS_CONF_RES_16 | ADS_CONF_CHAN_1;
+  _conversionDelay = ADS1115_CONVERSION_DELAY;
+  _bitShift = 0;
+  _maxPorts = 1;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// ADS1115
+//
+ADS1115::ADS1115(uint8_t address, TwoWire *wire)
+{
+  _address = address;
+  _wire = wire;
+  _config = ADS_CONF_COMP | ADS_CONF_GAIN | ADS_CONF_RES_16 | ADS_CONF_CHAN_4;
+  _conversionDelay = ADS1115_CONVERSION_DELAY;
+  _bitShift = 0;
+  _maxPorts = 4;
+}
+
+int16_t ADS1115::readADC_Differential_0_3()
+{
+  return _readADC(ADS1X15_MUX_DIFF_0_3);
+}
+
+int16_t ADS1115::readADC_Differential_1_3()
+{
+  return _readADC(ADS1X15_MUX_DIFF_1_3);
+}
+
+int16_t ADS1115::readADC_Differential_2_3()
+{
+  return _readADC(ADS1X15_MUX_DIFF_2_3);
+}
+
+int16_t ADS1115::readADC_Differential_0_2()
+{
+  return readADC(2) - readADC(0);
+}
+
+int16_t ADS1115::readADC_Differential_1_2()
+{
+  return readADC(2) - readADC(1);;
+}
+
+void ADS1115::requestADC_Differential_0_3()
+{
+  _requestADC(ADS1X15_MUX_DIFF_0_3);
+}
+
+void ADS1115::requestADC_Differential_1_3()
+{
+  _requestADC(ADS1X15_MUX_DIFF_1_3);
+}
+
+void ADS1115::requestADC_Differential_2_3()
+{
+  _requestADC(ADS1X15_MUX_DIFF_2_3);
+}
+
+// --- END OF FILE
diff --git a/ADS1X15.h b/ADS1X15.h
new file mode 100644
index 0000000..2ec9dd7
--- /dev/null
+++ b/ADS1X15.h
@@ -0,0 +1,224 @@
+#pragma once
+//
+//    FILE: ADS1X15.H
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.3.3
+//    DATE: 2013-03-24
+// PUPROSE: Arduino library for ADS1015 and ADS1115
+//     URL: https://github.com/RobTillaart/ADS1X15
+//
+
+
+#include "Arduino.h"
+#include "Wire.h"
+
+#define ADS1X15_LIB_VERSION               (F("0.3.3"))
+
+// allow compile time default address
+// address in { 0x48, 0x49, 0x4A, 0x4B }, no test...
+#ifndef ADS1015_ADDRESS
+#define ADS1015_ADDRESS             0x48
+#endif
+
+#ifndef ADS1115_ADDRESS
+#define ADS1115_ADDRESS             0x48
+#endif
+
+
+#define ADS1X15_OK                  0
+#define ADS1X15_INVALID_VOLTAGE     -100
+#define ADS1X15_INVALID_GAIN        0xFF
+#define ADS1X15_INVALID_MODE        0xFE
+
+
+class ADS1X15
+{
+public:
+  void     reset();
+
+#if defined (ESP8266) || defined(ESP32)
+  bool     begin(uint8_t sda, uint8_t scl);
+#endif
+  bool     begin();
+  bool     isConnected();
+
+  //       GAIN
+  // 0  =  ±6.144V  default
+  // 1  =  ±4.096V
+  // 2  =  ±2.048V
+  // 4  =  ±1.024V
+  // 8  =  ±0.512V
+  // 16 =  ±0.256V
+  void     setGain(uint8_t gain = 0);    // invalid values are mapped to 0 (default).
+  uint8_t  getGain();                    // 0xFF == invalid gain error.
+
+  // both may return ADS1X15_INVALID_VOLTAGE if the gain is invalid.
+  float    toVoltage(int16_t val = 1);   //  converts raw to voltage
+  float    getMaxVoltage();              //  -100 == invalid voltage error
+
+  // 0  =  CONTINUOUS
+  // 1  =  SINGLE      default
+  void     setMode(uint8_t mode = 1);    //  invalid values are mapped to 1 (default)
+  uint8_t  getMode();                    //  0xFE == invalid mode error.
+
+  // 0  =  slowest
+  // 7  =  fastest
+  // 4  =  default
+  void     setDataRate(uint8_t dataRate = 4); // invalid values are mapped on 4 (default)
+  uint8_t  getDataRate();                     // actual speed depends on device
+
+  int16_t  readADC(uint8_t pin);
+  int16_t  readADC_Differential_0_1();
+
+  // used by continuous mode and async mode.
+  int16_t  getLastValue() { return getValue(); };  // will be obsolete in the future 0.4.0
+  int16_t  getValue();
+
+
+  // ASYNC INTERFACE
+  // requestADC(pin) -> isBusy() or isReady() -> getValue(); 
+  // see examples
+  void     requestADC(uint8_t pin);
+  void     requestADC_Differential_0_1();
+  bool     isBusy();
+  bool     isReady();
+
+
+  // COMPARATOR
+  // 0    = TRADITIONAL   > high          => on      < low   => off
+  // else = WINDOW        > high or < low => on      between => off
+  void     setComparatorMode(uint8_t mode) { _compMode = mode == 0 ? 0 : 1; };
+  uint8_t  getComparatorMode()             { return _compMode; };
+
+  // 0    = LOW (default)
+  // else = HIGH
+  void     setComparatorPolarity(uint8_t pol) { _compPol = pol ? 0 : 1; };
+  uint8_t  getComparatorPolarity()            { return _compPol; };
+
+  // 0    = NON LATCH
+  // else = LATCH
+  void     setComparatorLatch(uint8_t latch) { _compLatch = latch ? 0 : 1; };
+  uint8_t  getComparatorLatch()              { return _compLatch; };
+
+  // 0   = trigger alert after 1 conversion
+  // 1   = trigger alert after 2 conversions
+  // 2   = trigger alert after 4 conversions
+  // 3   = Disable comparator =  default, also for all other values.
+  void     setComparatorQueConvert(uint8_t mode) { _compQueConvert = (mode < 3) ? mode : 3; };
+  uint8_t  getComparatorQueConvert()             { return _compQueConvert; };
+
+  void     setComparatorThresholdLow(int16_t lo);
+  int16_t  getComparatorThresholdLow();
+  void     setComparatorThresholdHigh(int16_t hi);
+  int16_t  getComparatorThresholdHigh();
+
+
+  int8_t   getError();
+
+  void     setWireClock(uint32_t clockSpeed);
+  // proto - getWireClock returns the value set by setWireClock not necessary the actual value
+  uint32_t getWireClock();
+
+protected:
+  ADS1X15();
+
+  // CONFIGURATION
+  // BIT  DESCRIPTION
+  // 0    # channels        0 == 1    1 == 4;
+  // 1    0
+  // 2    # resolution      0 == 12   1 == 16
+  // 3    0
+  // 4    has gain          0 = NO    1 = YES
+  // 5    has comparator    0 = NO    1 = YES
+  // 6    0
+  // 7    0
+  uint8_t  _config;
+  uint8_t  _maxPorts;
+  uint8_t  _address;
+  uint8_t  _conversionDelay;
+  uint8_t  _bitShift;
+  uint16_t _gain;
+  uint16_t _mode;
+  uint16_t _datarate;
+
+  // COMPARATOR variables
+  // TODO merge these into one COMPARATOR MASK?  (low priority)
+  //      would speed up code in _requestADC() and save 3 bytes RAM.
+  // TODO boolean flags for first three, or make it mask value that 
+  //      can be or-ed.   (low priority)
+  uint8_t  _compMode;
+  uint8_t  _compPol;
+  uint8_t  _compLatch;
+  uint8_t  _compQueConvert;
+
+  int16_t  _readADC(uint16_t readmode);
+  void     _requestADC(uint16_t readmode);
+  bool     _writeRegister(uint8_t address, uint8_t reg, uint16_t value);
+  uint16_t _readRegister(uint8_t address, uint8_t reg);
+  int8_t   _err = ADS1X15_OK;
+
+  TwoWire*  _wire;
+  uint32_t  _clockSpeed = 0;
+};
+
+///////////////////////////////////////////////////////////////////////////
+//
+// Derived classes from ADS1X15
+//
+class ADS1013 : public ADS1X15
+{
+public:
+  ADS1013(uint8_t Address = ADS1015_ADDRESS, TwoWire *wire = &Wire);
+};
+
+class ADS1014 : public ADS1X15
+{
+public:
+  ADS1014(uint8_t Address = ADS1015_ADDRESS, TwoWire *wire = &Wire);
+};
+
+class ADS1015 : public ADS1X15
+{
+public:
+  ADS1015(uint8_t Address = ADS1015_ADDRESS, TwoWire *wire = &Wire);
+  int16_t  readADC_Differential_0_3();
+  int16_t  readADC_Differential_1_3();
+  int16_t  readADC_Differential_2_3();
+  int16_t  readADC_Differential_0_2();  // not possible in async
+  int16_t  readADC_Differential_1_2();  // not possible in async
+  void     requestADC_Differential_0_3();
+  void     requestADC_Differential_1_3();
+  void     requestADC_Differential_2_3();
+};
+
+///////////////////////////////////////////////////////////////////////////
+//
+// Derived classes from ADS1X15
+//
+class ADS1113 : public ADS1X15
+{
+public:
+  ADS1113(uint8_t address = ADS1115_ADDRESS, TwoWire *wire = &Wire);
+};
+
+class ADS1114 : public ADS1X15
+{
+public:
+  ADS1114(uint8_t address = ADS1115_ADDRESS, TwoWire *wire = &Wire);
+};
+
+class ADS1115 : public ADS1X15
+{
+public:
+  ADS1115(uint8_t address = ADS1115_ADDRESS, TwoWire *wire = &Wire);
+  int16_t  readADC_Differential_0_3();
+  int16_t  readADC_Differential_1_3();
+  int16_t  readADC_Differential_2_3();
+  int16_t  readADC_Differential_0_2();  // not possible in async
+  int16_t  readADC_Differential_1_2();  // not possible in async
+  void     requestADC_Differential_0_3();
+  void     requestADC_Differential_1_3();
+  void     requestADC_Differential_2_3();
+};
+
+// --- END OF FILE ---
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..39d07e3
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2013-2021 Rob Tillaart
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..441b626
--- /dev/null
+++ b/README.md
@@ -0,0 +1,322 @@
+
+[![Arduino CI](https://github.com/RobTillaart/ADS1X15/workflows/Arduino%20CI/badge.svg)](https://github.com/marketplace/actions/arduino_ci)
+[![Arduino-lint](https://github.com/RobTillaart/ADS1X15/actions/workflows/arduino-lint.yml/badge.svg)](https://github.com/RobTillaart/ADS1X15/actions/workflows/arduino-lint.yml)
+[![JSON check](https://github.com/RobTillaart/ADS1X15/actions/workflows/jsoncheck.yml/badge.svg)](https://github.com/RobTillaart/ADS1X15/actions/workflows/jsoncheck.yml)
+[![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://github.com/RobTillaart/ADS1X15/blob/master/LICENSE)
+[![GitHub release](https://img.shields.io/github/release/RobTillaart/ADS1X15.svg?maxAge=3600)](https://github.com/RobTillaart/ADS1X15/releases)
+
+# ADS1X15
+
+Arduino library for I2C ADC ADS1015, ADS1115,
+
+
+## Description
+
+This library should work for the devices mentioned below,
+although not all sensors support all functionality.
+
+| Device  | Channels | Resolution | Max sps | Comparator | ProgGainAMP | Notes  |
+|:-------:|:--------:|:----------:|:-------:|:----------:|:-----------:|:-------|
+| ADS1013 |    1     |     12     |  3300   |     N      |      N      |        |
+| ADS1014 |    1     |     12     |  3300   |     Y      |      Y      |        |
+| ADS1015 |    4     |     12     |  3300   |     Y      |      Y      |        |
+| ADS1113 |    1     |     16     |  860    |     N      |      N      |        |
+| ADS1114 |    1     |     16     |  860    |     Y      |      Y      |        |
+| ADS1115 |    4     |     16     |  860    |     Y      |      Y      | Tested |
+
+As the 1015 and the 1115 are both 4 channels these are the most
+interesting from functionality point of view as these can also do
+differential measurement.
+
+
+## Interface
+
+The address of the ADS1113/4/5 is determined by to which pin the ADDR
+is connected to:
+
+| ADDR pin connected to | Address | Notes   |
+|:---------------------:|:-------:|:-------:|
+|      GND              |   0x48  | default |
+|      VDD              |   0x49  |         |
+|      SDA              |   0x4A  |         |
+|      SCL              |   0x4B  |         |
+
+
+- **ADS1x15()** constructor, should not be used.
+- **ADS1013(address, TwoWire \*wire = &Wire)** Constructor with device address, 
+and optional the Wire interface as parameter.
+- **ADS1014(address, TwoWire \*wire = &Wire)** Constructor with device address, 
+and optional the Wire interface as parameter.
+- **ADS1015(address, TwoWire \*wire = &Wire)** Constructor with device address, 
+and optional the Wire interface as parameter.
+- **ADS1113(address, TwoWire \*wire = &Wire)** Constructor with device address, 
+and optional the Wire interface as parameter.
+- **ADS1114(address, TwoWire \*wire = &Wire)** Constructor with device address, 
+and optional the Wire interface as parameter.
+- **ADS1115(address, TwoWire \*wire = &Wire)** Constructor with device address, 
+and optional the Wire interface as parameter.
+
+The function **void setWireClock(uint32_t speed)** is used to set the clock speed 
+of the used I2C interface. 
+
+The function **uint32_t getWireClock()** is a prototype. 
+It returns the value set by setWireClock().
+This is not necessary the actual value. 
+When no value is set **getWireClock()** returns 0.
+Need to implement a read / calculate from low level I2C code (e.g. TWBR on AVR),
+better the Arduino Wire lib should support this call (ESP32 does).
+
+After construction the **ADS.begin()** need to be called. This will return false 
+if an invalid address is used.
+The function **bool isConnected()** can be used to verify the reading of the ADS.
+The function **void reset()** is sets the parameters to their initial value as 
+in the constructor.
+
+
+#### Programmable Gain
+
+- **void setGain(uint8_t gain)** set the gain value, indicating the maxVoltage that can be measured
+Adjusting the gain allows one to make more precise measurements. 
+Note: the gain is not set in the device until an explicit read/request of the ADC (any read call will do).
+See table below.
+- **uint8_t getGain()** returns the gain value (index).
+
+| PGA value | Max Voltage | Notes   |
+|:---------:|:-----------:|:-------:|
+|      0    |   ±6.144V   | default |
+|      1    |   ±4.096V   |         |
+|      2    |   ±2.048V   |         |
+|      4    |   ±1.024V   |         |
+|      8    |   ±0.512V   |         |
+|      16   |   ±0.256V   |         |
+
+- **float getMaxVoltage()** returns the max voltage with the current gain.
+- **float toVoltage(int16_t raw = 1)** converts a raw measurement to a voltage.
+Can be used for normal and differential measurements.
+The default value of 1 returns the conversion factor for any raw number.
+
+The voltage factor can also be used to set HIGH and LOW threshold registers 
+with a voltage in the comparator mode.
+Check the examples.
+
+```cpp
+  float f = ADS.toVoltage();
+  ADS.setComparatorThresholdLow( 3.0 / f );
+  ADS.setComparatorThresholdLow( 4.3 / f );
+```
+
+
+#### Operational mode
+
+The ADS sensor can operate in single shot or continuous mode. 
+Depending on how often one needs a conversion one can tune the mode.
+- **void setMode(uint8_t mode)** 0 = CONTINUOUS, 1 = SINGLE (default)
+Note: the mode is not set in the device until an explicit read/request of the ADC (any read call will do).
+- **uint8_t getMode()** returns current mode 0 or 1, or ADS1X15_INVALID_MODE = 0xFE.
+
+
+
+#### Data rate
+
+- **void setDataRate(uint8_t dataRate)** Data rate depends on type of device.
+For all devices the index 0..7 can be used, see table below.
+Values above 7 ==> will be set to the default 4.
+Note: the data rate is not set in the device until an explicit read/request of the ADC (any read call will do).
+- **uint8_t getDataRate()** returns the current data rate (index).
+
+The library has no means to convert this index to the actual numbers
+as that would take 32 bytes. 
+
+Data rate in samples per second, based on datasheet numbers.
+
+| data rate | ADS101x | ADS 111x | Notes   |
+|:---------:|--------:|---------:|:-------:|
+|     0     |   128   |   8      | slowest |
+|     1     |   250   |   16     |         |
+|     2     |   490   |   32     |         |
+|     3     |   920   |   64     |         |
+|     4     |   1600  |   128    | default |
+|     5     |   2400  |   250    |         |
+|     6     |   3300  |   475    |         |
+|     7     |   3300  |   860    | fastest |
+
+
+#### ReadADC Single mode
+
+Reading the ADC is very straightforward, the **readADC()** function handles
+all in one call. Under the hood it uses the asynchronous calls.
+- **int16_t readADC(uint8_t pin)** normal ADC functionality, pin = 0..3. 
+If the pin number is out of range, this function will return 0.
+
+To read the ADC in an asynchronous way (e.g. to minimize blocking) one has to use three calls:
+- **void requestADC(uint8_t pin)**  Start the conversion. pin = 0..3. 
+- **bool isBusy()** Is the conversion not ready yet? Works only in SINGLE mode!
+- **bool isReady()** Is the conversion ready? Works only in SINGLE mode!  (= wrapper around **isBusy()** )  
+- **int16_t getValue()** Read the result of the conversion.
+
+
+in terms of code
+```cpp
+
+  void setup()
+  {
+    // other setup things here
+    ADS.setMode(1);               // SINGLE SHOT MODE
+    ADS.requestADC(pin);
+  }
+
+
+  void loop()
+  {
+    if (ADS.isReady())
+    {
+      val = ADS.getValue();
+      ADS.requestADC(pin);       // request new conversion
+    }
+    // do other things here
+  }
+
+```
+See examples
+
+
+## ReadADC Differential
+
+For reading the ADC in a differential way there are 4 calls possible.
+- **int16_t readADC_Differential_0_1()** returns the difference between 2 ADC pins.
+- **int16_t readADC_Differential_0_3()** ADS1x15 only
+- **int16_t readADC_Differential_1_3()** ADS1x15 only
+- **int16_t readADC_Differential_2_3()** ADS1x15 only
+- **int16_t readADC_Differential_0_2()** ADS1x15 only - in software (no async equivalent)
+- **int16_t readADC_Differential_1_2()** ADS1x15 only - in software (no async equivalent)
+
+The differential reading of the ADC can also be done with asynchronous calls.
+- **void requestADC_Differential_0_1()** starts conversion for differential reading
+- **void requestADC_Differential_0_3()** ADS1x15 only
+- **void requestADC_Differential_1_3()** ADS1x15 only
+- **void requestADC_Differential_2_3()** ADS1x15 only
+
+After one of these calls one need to call
+- **int16_t getValue()** Read the result of the last conversion.
+
+The readiness of a CONTINUOUS conversion can only be detected by the RDY line.
+Use interrupt for this, see examples.
+
+
+#### ReadADC continuous mode
+
+To use the continuous mode one need three calls
+- **void setMode(0)** 0 = CONTINUOUS, 1 = SINGLE (default).
+Note: the mode is not set in the device until an explicit read/request of the ADC (any read call will do).
+- **int16_t readADC(uint8_t pin)** or **void requestADC(uint8_t pin)** to get the continuous mode started.
+- **int16_t getValue()** to return the last value read by the device. 
+Note this can be a different pin, so be warned.
+Calling this over and over again can give the same value multiple times.
+
+By using **bool isBusy()** or **bool isReady()** one can wait until new data is available.
+Note this only works in the SINGLE_SHOT modus.
+
+In continuous mode one should use the **ALERT/RDY** pin to trigger via hardware the readiness of the conversion.
+This can be done by using an interrupt.
+
+See examples.
+
+
+#### Threshold registers ==> mode RDY pin
+
+If the thresholdHigh is set to 0x0100 and the thresholdLow to 0x0000
+the **ALERT/RDY** pin is triggered when a conversion is ready.
+- **void setComparatorThresholdLow(int16_t lo)** writes value to device directly.
+- **void setComparatorThresholdHigh(int16_t hi)** writes value to device directly.
+- **int16_t getComparatorThresholdLow()** reads value from device.
+- **int16_t getComparatorThresholdHigh()** reads value from device.
+
+See examples.
+
+
+## Comparator
+
+Please read Page 15 of the datasheet as the behaviour of the
+comparator is not trivial.
+
+NOTE: all comparator settings are copied to the device only after an explicit 
+**readADC()** or **requestADC()**
+
+
+#### Comparator Mode
+
+When configured as a **TRADITIONAL** comparator, the **ALERT/RDY** pin asserts
+(active low by default) when conversion data exceed the limit set in the
+high threshold register. The comparator then de-asserts when the input
+signal falls below the low threshold register value.
+
+- **void setComparatorMode(uint8_t mode)** value 0 = TRADITIONAL 1 = WINDOW, 
+- **uint8_t getComparatorMode()** returns value set.
+  
+  
+If the comparator **LATCH** is set, the **ALERT/RDY** pin asserts and it will be
+reset after reading the sensor (conversion register) again.
+*An SMB alert command (00011001) on the I2C bus will also reset the alert state.*
+*Not implemented in the library (yet)*
+
+In **WINDOW** comparator mode, the **ALERT/RDY** pin asserts if conversion data exceeds
+the high threshold register or falls below the low threshold register.
+In this mode the alert is held if the **LATCH** is set. This is similar as above.
+
+
+#### Polarity
+
+Default state of the **ALERT/RDY** pin is **LOW**, can be to set **HIGH**.
+
+- **void setComparatorPolarity(uint8_t pol)** 
+Flag is only explicitly set after a **readADC()** or a **requestADC()**
+- **uint8_t getComparatorPolarity()** returns value set. 
+  
+
+#### Latch
+
+Holds the **ALERT/RDY** to **HIGH** (or **LOW** depending on polarity) after triggered
+even if actual value has been 'restored to normal' value.
+
+- **void setComparatorLatch(uint8_t latch)** 0 = NO LATCH, not 0 = LATCH
+- **uint8_t getComparatorLatch()** returns value set.
+
+
+#### QueConvert
+
+Set the number of conversions before trigger activates.
+The **void setComparatorQueConvert(uint8_t mode)** is used to set the number of
+conversions that exceed the threshold before the **ALERT/RDY** pin is set **HIGH**.
+A value of 3 (or above) effectively disables the comparator. See table below.
+
+- **void setComparatorQueConvert(uint8_t mode)** See table below.
+- **uint8_t getComparatorQueConvert()**  returns value set.
+
+| value | meaning                           | Notes   |
+|:-----:|:----------------------------------|:--------|
+|   0   | trigger alert after 1 conversion  |         |
+|   1   | trigger alert after 2 conversions |         |
+|   2   | trigger alert after 4 conversions |         |
+|   3   | Disable comparator                | default |
+
+
+#### Threshold registers comparator mode
+
+Depending on the comparator mode **TRADITIONAL** or **WINDOW** the thresholds registers
+mean something different see - Comparator Mode above or datasheet.
+- **void setComparatorThresholdLow(int16_t lo)** set the low threshold; take care the hi >= lo.
+- **void setComparatorThresholdHigh(int16_t hi)**  set the high threshold; take care the hi >= lo.
+- **int16_t getComparatorThresholdLow()** reads value from device.
+- **int16_t getComparatorThresholdHigh()** reads value from device.
+
+
+## Future ideas & improvements
+
+- Improve documentation
+- More examples ?
+- SMB alert command (00011001) on I2C bus?
+
+
+## Operation
+
+See examples
diff --git a/examples/ADS_async_16_channel/ADS_async_16_channel.ino b/examples/ADS_async_16_channel/ADS_async_16_channel.ino
new file mode 100644
index 0000000..4fcc8bb
--- /dev/null
+++ b/examples/ADS_async_16_channel/ADS_async_16_channel.ino
@@ -0,0 +1,119 @@
+//
+//    FILE: ADS_async_16_channel.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.0
+// PURPOSE: demo reading four ADS1115 modules in parallel
+//    DATE: 2021-07-06
+//     URL: https://github.com/RobTillaart/ADS1X15
+
+
+// Note all IO with the sensors are guarded by an isConnected()
+// this is max robust, in non critical application one may either
+// cache the value or only verify it in setup (least robust).
+// Less robust may cause the application to hang - watchdog reset ?
+
+
+#include "ADS1X15.h"
+
+
+ADS1115 ADS[4];
+uint16_t val[16];
+int idx = 0;
+
+uint32_t last = 0, now = 0;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  for (uint8_t i = 0; i < 4; i++)
+  {
+    uint8_t address = 0x48 + i;
+    ADS[i] = ADS1115(address);
+
+    Serial.print(address, HEX);
+    Serial.print("  ");
+    Serial.println(ADS[i].begin() ? "connected" : "not connected");
+
+    ADS[i].setDataRate(4);  // 7 is fastest, but more noise
+  }
+  ADS_request_all();
+}
+
+
+void loop()
+{
+  // Serial.println(__FUNCTION__);
+  // wait until all is read...
+  while (ADS_read_all());
+
+  // we have all values
+  ADS_print_all();
+
+  delay(1000);      // wait a second.
+  ADS_request_all();
+}
+
+
+void ADS_request_all()
+{
+  //  Serial.println(__FUNCTION__);
+  for (int i = 0; i < 4; i++)
+  {
+    if (ADS[i].isConnected()) ADS[i].requestADC(idx);
+  }
+}
+
+
+bool ADS_read_all()
+{
+  for (int i = 0; i < 4; i++)
+  {
+    if (ADS[i].isConnected() && ADS[i].isBusy()) return true;
+  }
+  // Serial.print("IDX:\t");
+  // Serial.println(idx);
+  for (int i = 0; i < 4; i++)
+  {
+    if (ADS[i].isConnected())
+    {
+      val[i * 4 + idx] = ADS[i].getValue();
+    }
+  }
+  idx++;
+  if (idx < 4)
+  {
+    ADS_request_all();
+    return true;
+  }
+  idx = 0;
+  return false;
+}
+
+
+void ADS_print_all()
+{
+  // Serial.println(__FUNCTION__);
+  // TIMESTAMP
+  now = millis();
+  Serial.print(now - last);
+  last = now;
+  Serial.println();
+
+  // PRINT ALL VALUES
+  for (int i = 0; i < 4; i++)
+  {
+    for (int j = 0; j < 4; j++)
+    {
+      Serial.print(val[j * 4 + i]);
+      Serial.print("\t");
+    }
+    Serial.println();
+  }
+  Serial.println();
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_async_8_channel/ADS_async_8_channel.ino b/examples/ADS_async_8_channel/ADS_async_8_channel.ino
new file mode 100644
index 0000000..3e0ad54
--- /dev/null
+++ b/examples/ADS_async_8_channel/ADS_async_8_channel.ino
@@ -0,0 +1,136 @@
+//
+//    FILE: ADS_async_8_channel.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: demo reading two ADS1115 modules in parallel
+//    DATE: 2021-07-05
+//     URL: https://github.com/RobTillaart/ADS1X15
+
+
+// Note all IO with the sensors are guarded by an isConnected()
+// this is max robust, in non critical application one may either
+// cache the value or only verify it in setup (least robust).
+// Less robust may cause the application to hang - watchdog reset ?
+
+
+#include "ADS1X15.h"
+
+
+ADS1115 ADS0(0x48);
+ADS1115 ADS1(0x49);
+//ADS1115 ADS2(0x4A);
+//ADS1115 ADS3(0x4B);
+
+int16_t val0[4] = { 0, 0, 0, 0 };
+int16_t val1[4] = { 0, 0, 0, 0 };
+//int16_t val2[4] = { 0, 0, 0, 0 };
+//int16_t val3[4] = { 0, 0, 0, 0 };
+int     idx = 0;
+
+uint32_t lastTime = 0;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS0.begin();
+  ADS1.begin();
+  //  ADS2.begin();
+  //  ADS3.begin();
+
+  Serial.println(ADS0.isConnected());
+  Serial.println(ADS1.isConnected());
+  //  Serial.println(ADS2.isConnected());
+  //  Serial.println(ADS3.isConnected());
+
+  ADS0.setDataRate(4);  // 7 is fastest, but more noise
+  ADS1.setDataRate(4);
+  //  ADS2.setDataRate(4);
+  //  ADS3.setDataRate(4);
+
+  idx = 0;
+  ADS_request_all();
+}
+
+
+void loop()
+{
+  // wait until all is read...
+  while (ADS_read_all());
+
+  // we have all 8 values
+  ADS_print_all();
+
+  delay(1000);      // wait a second.
+  ADS_request_all();
+}
+
+
+void ADS_request_all()
+{
+  if (ADS0.isConnected()) ADS0.requestADC(idx);
+  if (ADS1.isConnected()) ADS1.requestADC(idx);
+  //  if (ADS2.isConnected()) ADS2.requestADC(idx);
+  //  if (ADS3.isConnected()) ADS3.requestADC(idx);
+}
+
+
+bool ADS_read_all()
+{
+  if (ADS0.isConnected() && ADS0.isBusy()) return true;
+  if (ADS1.isConnected() && ADS1.isBusy()) return true;
+  //  if (ADS2.isConnected() && ADS2.isBusy()) return true;
+  //  if (ADS3.isConnected() && ADS3.isBusy()) return true;
+
+  if (ADS0.isConnected()) val0[idx] = ADS0.getValue();
+  if (ADS1.isConnected()) val1[idx] = ADS1.getValue();
+  //  if (ADS2.isConnected()) val2[idx] = ADS2.getValue();
+  //  if (ADS3.isConnected()) val3[idx] = ADS3.getValue();
+  idx++;
+  if (idx < 4)
+  {
+    ADS_request_all();
+    return true;
+  }
+  idx = 0;
+  return false;
+}
+
+
+void ADS_print_all()
+{
+  uint32_t now = millis();
+  Serial.println(now - lastTime);
+  lastTime = now;
+
+  // PRINT ALL VALUES OF ADC0
+  for (int i = 0; i < 4; i++)
+  {
+    Serial.print(val0[i]);
+    Serial.print("\t");
+  }
+  // PRINT ALL VALUES OF ADC1
+  for (int i = 0; i < 4; i++)
+  {
+    Serial.print(val1[i]);
+    Serial.print("\t");
+  }
+  Serial.println();
+  //  // PRINT ALL VALUES OF ADC2
+  //  for (int i = 0; i < 4; i++)
+  //  {
+  //    Serial.print(val2[i]);
+  //    Serial.print("\t");
+  //  }
+  //  // PRINT ALL VALUES OF ADC3
+  //  for (int i = 0; i < 4; i++)
+  //  {
+  //    Serial.print(val3[i]);
+  //    Serial.print("\t");
+  //  }
+  //  Serial.println();
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_async_differential/ADS_async_differential.ino b/examples/ADS_async_differential/ADS_async_differential.ino
new file mode 100644
index 0000000..36103c9
--- /dev/null
+++ b/examples/ADS_async_differential/ADS_async_differential.ino
@@ -0,0 +1,95 @@
+//
+//    FILE: ADS_async_differential.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read multiple differential continuously
+//
+
+// test
+// connect 4 potmeters
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x  - connect to AIN0..4.
+//
+//
+
+
+#include "ADS1X15.h"
+
+// choose you sensor
+// ADS1013 ADS(0x48);
+// ADS1014 ADS(0x48);
+// ADS1015 ADS(0x48);
+// ADS1113 ADS(0x48);
+// ADS1114 ADS(0x48);
+ADS1115 ADS(0x48);
+
+
+uint8_t pair = 01;
+int16_t val_01 = 0;
+int16_t val_23 = 0;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);        // 6.144 volt
+  ADS.setDataRate(4);    // medium
+
+  // single shot mode
+  ADS.setMode(1);
+  // start with first pair
+  pair = 01;
+  // trigger first read
+  ADS.requestADC_Differential_0_1();
+}
+
+void loop()
+{
+  if (handleConversion() == true)
+  {
+    Serial.print("COMP:\t");
+    Serial.print(val_01);
+    Serial.print("\t");
+    Serial.print(val_23);
+    Serial.println();
+  }
+
+  // do other stuff here
+  delay(10);
+}
+
+
+// can be changed to hold other differentials reads too.
+bool handleConversion()
+{
+  if (ADS.isReady())
+  {
+    if (pair == 01)
+    {
+      val_01 = ADS.getValue();
+      pair = 23;
+      ADS.requestADC_Differential_2_3();
+      return false;  // only one done
+    }
+
+    // last of series to check
+    if (pair == 23)
+    {
+      val_23 = ADS.getValue();
+      pair = 01;
+      ADS.requestADC_Differential_0_1();
+      return true;   // both are updated
+    }
+  }
+  return false;  // default not all read
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_continuous/ADS_continuous.ino b/examples/ADS_continuous/ADS_continuous.ino
new file mode 100644
index 0000000..2e0c343
--- /dev/null
+++ b/examples/ADS_continuous/ADS_continuous.ino
@@ -0,0 +1,47 @@
+//
+//    FILE: ADS_continuous.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.1
+// PURPOSE: read analog input
+//
+
+// test
+// connect 1 potmeter
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+
+
+#include "ADS1X15.h"
+
+// choose you sensor
+// ADS1013 ADS(0x48);
+// ADS1014 ADS(0x48);
+// ADS1015 ADS(0x48);
+// ADS1113 ADS(0x48);
+// ADS1114 ADS(0x48);
+ADS1115 ADS(0x48);
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);      // 6.144 volt
+  ADS.setDataRate(7);  // fast
+  ADS.setMode(0);      // continuous mode
+  ADS.readADC(0);      // first read to trigger
+}
+
+void loop()
+{
+  Serial.println(ADS.getValue());
+}
+
+// -- END OF FILE --
\ No newline at end of file
diff --git a/examples/ADS_continuous_4_channel/ADS_continuous_4_channel.ino b/examples/ADS_continuous_4_channel/ADS_continuous_4_channel.ino
new file mode 100644
index 0000000..22666be
--- /dev/null
+++ b/examples/ADS_continuous_4_channel/ADS_continuous_4_channel.ino
@@ -0,0 +1,94 @@
+//
+//    FILE: ADS_continuous_4_channel.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.2
+// PURPOSE: read multiple analog inputs continuously
+//          interrupt driven to catch all conversions.
+//
+
+// test
+// connect multiple potmeters
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x  - connect to AIN0..4.
+//
+// for the test it is good to have AIN3 connected to 5V and AIN4 to GND
+// so one can see these as references in the output.
+//
+
+#include "ADS1X15.h"
+
+// choose you sensor
+// ADS1013 ADS(0x48);
+// ADS1014 ADS(0x48);
+// ADS1015 ADS(0x48);
+// ADS1113 ADS(0x48);
+// ADS1114 ADS(0x48);
+ADS1115 ADS(0x48);
+
+volatile bool RDY = false;
+uint8_t channel = 0;
+int16_t val[4] = { 0, 0, 0, 0 };
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  pinMode(2, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(2), adsReady, RISING);
+
+  ADS.begin();
+  ADS.setGain(0);        // 6.144 volt
+  ADS.setDataRate(7);    // slow
+
+  // SET ALERT RDY PIN
+  ADS.setComparatorThresholdHigh(0x8000);
+  ADS.setComparatorThresholdLow(0x0000);
+  ADS.setComparatorQueConvert(0);
+
+  // SET INTERRUPT HANDLER TO CATCH CONVERSION READY
+  pinMode(2, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(2), adsReady, RISING);
+
+  ADS.setMode(0);        // continuous mode
+  ADS.readADC(channel);     // trigger first read
+}
+
+void loop()
+{
+  handleConversion();
+
+  for (int i = 0; i < 4; i++)
+  {
+    Serial.print(val[i]);
+    Serial.print('\t');
+    handleConversion();
+  }
+  Serial.println();
+  delay(100);
+}
+
+void adsReady()
+{
+  RDY = true;
+}
+
+void handleConversion()
+{
+  if (RDY)
+  {
+    // save the value
+    val[channel] = ADS.getValue();
+    // request next channel
+    channel++;
+    if (channel >= 4) channel = 0;
+    ADS.readADC(channel);
+    RDY = false;
+  }
+}
+// -- END OF FILE --
diff --git a/examples/ADS_continuous_8_channel/ADS_continuous_8_channel.ino b/examples/ADS_continuous_8_channel/ADS_continuous_8_channel.ino
new file mode 100644
index 0000000..cee55b0
--- /dev/null
+++ b/examples/ADS_continuous_8_channel/ADS_continuous_8_channel.ino
@@ -0,0 +1,126 @@
+//
+//    FILE: ADS_continuous_8_channel.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.1
+// PURPOSE: read multiple analog inputs continuously
+//          interrupt driven to catch all conversions.
+//
+
+// test
+// connect multiple potmeters to 2 ADS1115
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x  - connect to AIN0..4.
+//
+// for the test it is good to have AIN3 connected to 5V and AIN4 to GND
+// so one can see these as references in the output.
+//
+
+#include "ADS1X15.h"
+
+// adjust addresses if needed
+ADS1115 ADS_1(0x49);
+ADS1115 ADS_2(0x48);
+
+volatile bool RDY_1 = false;
+volatile bool RDY_2 = false;
+uint8_t channel_1 = 0;
+uint8_t channel_2 = 0;
+int16_t val[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  // SETUP FIRST ADS1115
+  ADS_1.begin();
+  ADS_1.setGain(0);        // 6.144 volt
+  ADS_1.setDataRate(7);
+
+  // SET ALERT RDY PIN
+  ADS_1.setComparatorThresholdHigh(0x8000);
+  ADS_1.setComparatorThresholdLow(0x0000);
+  ADS_1.setComparatorQueConvert(0);
+
+  // SET INTERRUPT HANDLER TO CATCH CONVERSION READY
+  pinMode(2, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(2), adsReady_1, RISING);
+
+  ADS_1.setMode(0);          // continuous mode
+  ADS_1.readADC(channel_1);  // trigger first read
+
+
+  // SETUP SECOND ADS1115
+  ADS_2.begin();
+  ADS_2.setGain(0);        // 6.144 volt
+  ADS_2.setDataRate(7);
+
+  // SET ALERT RDY PIN
+  ADS_2.setComparatorThresholdHigh(0x8000);
+  ADS_2.setComparatorThresholdLow(0x0000);
+  ADS_2.setComparatorQueConvert(0);
+
+  // SET INTERRUPT HANDLER TO CATCH CONVERSION READY
+  pinMode(3, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(3), adsReady_2, RISING);
+
+  ADS_2.setMode(0);          // continuous mode
+  ADS_2.readADC(channel_2);  // trigger first read
+}
+
+void loop()
+{
+  handleConversion();
+
+  for (int i = 0; i < 8; i++)
+  {
+    Serial.print(val[i]);
+    Serial.print('\t');
+    handleConversion();
+  }
+  Serial.println();
+  delay(100);
+}
+
+// catch interrupt and set flag
+void adsReady_1()
+{
+  RDY_1 = true;
+}
+
+void adsReady_2()
+{
+  RDY_2 = true;
+}
+
+// handle conversions that are ready
+void handleConversion()
+{
+  if (RDY_1)
+  {
+    // save the last value
+    val[channel_1] = ADS_1.getValue();
+    // request next channel
+    channel_1++;
+    if (channel_1 >= 4) channel_1 = 0;
+    ADS_1.readADC(channel_1);
+    RDY_1 = false;
+  }
+  if (RDY_2)
+  {
+    // save the last value
+    val[4 + channel_2] = ADS_2.getValue();
+    // request next channel
+    channel_2++;
+    if (channel_2 >= 4) channel_2 = 0;
+    ADS_2.readADC(channel_2);
+    RDY_2 = false;
+  }
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_continuous_differential/ADS_continuous_differential.ino b/examples/ADS_continuous_differential/ADS_continuous_differential.ino
new file mode 100644
index 0000000..7a83336
--- /dev/null
+++ b/examples/ADS_continuous_differential/ADS_continuous_differential.ino
@@ -0,0 +1,123 @@
+//
+//    FILE: ADS_continuous_differential.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read multiple differential continuously
+//
+
+// test
+// connect 4 potmeters
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x  - connect to AIN0..4.
+//
+//
+
+
+#include "ADS1X15.h"
+
+// choose you sensor
+// ADS1013 ADS(0x48);
+// ADS1014 ADS(0x48);
+// ADS1015 ADS(0x48);
+// ADS1113 ADS(0x48);
+// ADS1114 ADS(0x48);
+ADS1115 ADS(0x48);
+
+
+// interrupt flag
+volatile bool RDY = false;
+// which pair to use for differential
+uint8_t pair = 01;
+// two values to hold differential measurements.
+int16_t val_01 = 0;
+int16_t val_23 = 0;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  // SET INTERRUPT HANDLER TO CATCH CONVERSION READY
+  pinMode(2, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(2), adsReady, RISING);
+
+  ADS.begin();
+  Serial.print("connected: ");
+  Serial.println(ADS.isConnected());
+  ADS.setGain(0);        // 6.144 volt
+  ADS.setDataRate(0);    // 0 = slow   4 = medium   7 = fast  (7 = fails )
+  // every step is about a factor 2 slower.
+
+  // SET ALERT RDY PIN
+  ADS.setComparatorThresholdHigh(0x8000);
+  ADS.setComparatorThresholdLow(0x0000);
+  ADS.setComparatorQueConvert(0);
+
+  // continuous mode
+  ADS.setMode(0);
+  // start with first pair
+  pair = 01;
+  // trigger first read
+  ADS.requestADC_Differential_0_1();
+}
+
+
+void loop()
+{
+  static uint32_t last = 0;
+  if (handleConversion() == true)
+  {
+    uint32_t now = millis();
+    Serial.print(now - last);
+    last = now;
+    Serial.print("\tCOMP:\t");
+    Serial.print(val_01);
+    Serial.print("\t");
+    Serial.print(val_23);
+    Serial.println();
+  }
+
+  // do other stuff here
+  // delay(10);
+}
+
+// interrupt handler, just sets the RDY flag
+void adsReady()
+{
+  RDY = true;
+}
+
+// can be changed to hold other differentials or normal reads too.
+bool handleConversion()
+{
+  if (RDY)
+  {
+    RDY = false;
+    if (pair == 01)
+    {
+      val_01 = ADS.getValue();
+      pair = 23;
+      ADS.requestADC_Differential_2_3();
+      return false;  // only one done
+    }
+
+    // last of series to check
+    if (pair == 23)
+    {
+      val_23 = ADS.getValue();
+      pair = 01;
+      ADS.requestADC_Differential_0_1();
+      return true;   // both are updated
+    }
+  }
+  return false;  // default not all read
+}
+
+
+// -- END OF FILE --
diff --git a/examples/ADS_differential/ADS_differential.ino b/examples/ADS_differential/ADS_differential.ino
new file mode 100644
index 0000000..91711a8
--- /dev/null
+++ b/examples/ADS_differential/ADS_differential.ino
@@ -0,0 +1,64 @@
+//
+//    FILE: ADS_differential.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.1
+// PURPOSE: read differential
+//
+
+// test 1
+// connect 2 potmeters in series
+//
+// GND ---[   x   ]------[   y   ]---- 5V
+//            |              |
+//
+// measure at x and y  (connect to AIN0 and AIN1). 
+// x should be lower or equal to y
+
+// test 2
+// connect 2 potmeters parallel
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// GND ---[   y   ]------ 5V
+//            |
+//
+// measure at x and y  (connect to AIN0 and AIN1).
+// range from -VDD .. +VDD are possible
+
+#include <ADS1X15.h>
+
+ADS1115 ADS(0x48);
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);
+}
+
+void loop() 
+{
+  int16_t val_01 = ADS.readADC_Differential_0_1();  
+  int16_t val_03 = ADS.readADC_Differential_0_3();  
+  int16_t val_13 = ADS.readADC_Differential_1_3();  
+  int16_t val_23 = ADS.readADC_Differential_2_3(); 
+  float volts_01 = ADS.toVoltage(val_01); 
+  float volts_03 = ADS.toVoltage(val_03); 
+  float volts_13 = ADS.toVoltage(val_13); 
+  float volts_23 = ADS.toVoltage(val_23); 
+
+  Serial.print("\tval_01: "); Serial.print(val_01); Serial.print("\t"); Serial.println(volts_01, 3);
+  Serial.print("\tval_03: "); Serial.print(val_03); Serial.print("\t"); Serial.println(volts_03, 3);
+  Serial.print("\tval_13: "); Serial.print(val_13); Serial.print("\t"); Serial.println(volts_13, 3);
+  Serial.print("\tval_23: "); Serial.print(val_23); Serial.print("\t"); Serial.println(volts_23, 3);
+  Serial.println();
+
+  delay(1000);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_high_speed_differential/ADS_high_speed_differential.ino b/examples/ADS_high_speed_differential/ADS_high_speed_differential.ino
new file mode 100644
index 0000000..d548029
--- /dev/null
+++ b/examples/ADS_high_speed_differential/ADS_high_speed_differential.ino
@@ -0,0 +1,124 @@
+//
+//    FILE: ADS_high_speed_differential.ino.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read from 2 IC's for high speed differential
+//          interrupt driven to catch all conversions.
+//
+
+// test setup (not tested yet)
+// - connect 2 ADS1x15 to I2C bus
+// - connect potmeters to all channels
+// - code reads both at the same frequency
+//   and calculates differential per pair.
+//   as 2 ADC's go in parallel, two ADS1015 should get
+//   3000+ differential samples / second.
+//
+
+
+#include "ADS1X15.h"
+
+// adjust addresses if needed
+ADS1115 ADS_1(0x49);
+ADS1115 ADS_2(0x48);
+
+volatile bool RDY_1    = false;
+volatile bool RDY_2    = false;
+uint8_t channel        = 0;
+int32_t differential[4] = { 0, 0, 0, 0 };
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  // SETUP FIRST ADS1115
+  ADS_1.begin();
+  ADS_1.setGain(0);        // 6.144 volt
+  ADS_1.setDataRate(7);    // fastest conversion rate.
+
+  // SET ALERT RDY PIN
+  ADS_1.setComparatorThresholdHigh(0x8000);
+  ADS_1.setComparatorThresholdLow(0x0000);
+  ADS_1.setComparatorQueConvert(0);
+
+  // SET INTERRUPT HANDLER TO CATCH CONVERSION READY
+  pinMode(2, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(2), adsReady_1, RISING);
+
+  ADS_1.setMode(0);          // continuous mode
+  ADS_1.readADC(channel);    // trigger first read
+
+
+  // SETUP SECOND ADS1115
+  ADS_2.begin();
+  ADS_2.setGain(0);        // 6.144 volt
+  ADS_2.setDataRate(7);
+
+  // SET ALERT RDY PIN
+  ADS_2.setComparatorThresholdHigh(0x8000);
+  ADS_2.setComparatorThresholdLow(0x0000);
+  ADS_2.setComparatorQueConvert(0);
+
+  // SET INTERRUPT HANDLER TO CATCH CONVERSION READY
+  pinMode(3, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(3), adsReady_2, RISING);
+
+  ADS_2.setMode(0);          // continuous mode
+  ADS_2.readADC(channel);    // trigger first read
+}
+
+void loop()
+{
+  if (handleConversion() == true)
+  {
+    for (int i = 0; i < 4; i++)
+    {
+      Serial.print(differential[i]);
+      Serial.print("\t");
+    }
+    Serial.println();
+  }
+
+
+}
+
+
+// catch interrupt and set flag
+void adsReady_1()
+{
+  RDY_1 = true;
+}
+
+void adsReady_2()
+{
+  RDY_2 = true;
+}
+
+
+// handle conversions if both are ready
+bool handleConversion()
+{
+  if (RDY_1 == false) return false;
+  if (RDY_2 == false) return false;
+
+  // read the value of both
+  int16_t a = ADS_1.getValue();
+  int16_t b = ADS_2.getValue();
+  differential[channel] = a - b;
+  // request next channel
+  channel++;
+  if (channel >= 4) channel = 0;
+  ADS_1.readADC(channel);
+  ADS_2.readADC(channel);
+  RDY_1 = false;
+  RDY_2 = false;
+
+  return true;
+}
+
+
+// -- END OF FILE --
diff --git a/examples/ADS_minimum/ADS_minimum.ino b/examples/ADS_minimum/ADS_minimum.ino
new file mode 100644
index 0000000..d854951
--- /dev/null
+++ b/examples/ADS_minimum/ADS_minimum.ino
@@ -0,0 +1,46 @@
+//
+//    FILE: ADS_minimum.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read analog input
+//
+
+// test
+// connect 1 potmeter 
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+
+// view with Serial Plotter
+
+#include "ADS1X15.h"
+
+// choose you sensor
+// ADS1013 ADS(0x48);
+// ADS1014 ADS(0x48);
+// ADS1015 ADS(0x48);
+// ADS1113 ADS(0x48);
+// ADS1114 ADS(0x48);
+ADS1115 ADS(0x48);
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);  // 6.144 volt
+  Serial.println("Voltage");
+}
+
+void loop() 
+{
+  int16_t raw = ADS.readADC(0);
+  Serial.println(ADS.toVoltage(raw), 3);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_performance/ADS_performance.ino b/examples/ADS_performance/ADS_performance.ino
new file mode 100644
index 0000000..a94d8b8
--- /dev/null
+++ b/examples/ADS_performance/ADS_performance.ino
@@ -0,0 +1,92 @@
+//
+//    FILE: ADS_performance.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.1
+// PURPOSE: read analog input
+//
+
+// test
+// connect 1 potmeter
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+
+
+#include "ADS1X15.h"
+
+// choose you sensor
+// ADS1013 ADS(0x48);
+// ADS1014 ADS(0x48);
+// ADS1015 ADS(0x48);
+// ADS1113 ADS(0x48);
+// ADS1114 ADS(0x48);
+ADS1115 ADS(0x48);
+
+uint32_t start, d1, d2;
+int x;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);  // 6.144 volt
+
+  for (int dr = 0; dr < 8; dr++)
+  {
+    ADS.setDataRate(dr);
+    Serial.print("DR:\t");
+    Serial.println(dr);
+
+    test_single_shot();
+    test_continuous();
+
+    Serial.print("\t\tFACTOR:\t");
+    Serial.println(1.0 * d1 / d2);
+  }
+
+  Serial.println("\nDone...");
+}
+
+void loop()
+{
+}
+
+void test_single_shot()
+{
+  Serial.print(__FUNCTION__);
+
+  ADS.setMode(1);
+  start = micros();
+  x = ADS.readADC(0);
+  for (int i = 0; i < 100; i++)
+  {
+    x = ADS.readADC(0);
+  }
+  d1 = micros() - start;
+  Serial.print("\t");
+  Serial.println(d1);
+}
+
+void test_continuous()
+{
+  Serial.print(__FUNCTION__);
+
+  ADS.setMode(0);
+  start = micros();
+  x = ADS.readADC(0);
+  for (int i = 0; i < 100; i++)
+  {
+    x = ADS.getValue();
+  }
+  d2 = micros() - start;
+  Serial.print("\t\t");
+  Serial.println(d2);
+}
+
+// -- END OF FILE --
\ No newline at end of file
diff --git a/examples/ADS_read/ADS_read.ino b/examples/ADS_read/ADS_read.ino
new file mode 100644
index 0000000..dba2f67
--- /dev/null
+++ b/examples/ADS_read/ADS_read.ino
@@ -0,0 +1,51 @@
+//
+//    FILE: ADS_read.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.2.1
+// PURPOSE: read analog inputs - straightforward.
+//
+
+// test
+// connect 1 potmeter per port.
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+//
+
+#include "ADS1X15.h"
+
+ADS1115 ADS(0x48);
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+}
+
+void loop() 
+{
+  ADS.setGain(0);
+
+  int16_t val_0 = ADS.readADC(0);  
+  int16_t val_1 = ADS.readADC(1);  
+  int16_t val_2 = ADS.readADC(2);  
+  int16_t val_3 = ADS.readADC(3);  
+
+  float f = ADS.toVoltage(1);  // voltage factor
+
+  Serial.print("\tAnalog0: "); Serial.print(val_0); Serial.print('\t'); Serial.println(val_0 * f, 3);
+  Serial.print("\tAnalog1: "); Serial.print(val_1); Serial.print('\t'); Serial.println(val_1 * f, 3);
+  Serial.print("\tAnalog2: "); Serial.print(val_2); Serial.print('\t'); Serial.println(val_2 * f, 3);
+  Serial.print("\tAnalog3: "); Serial.print(val_3); Serial.print('\t'); Serial.println(val_3 * f, 3);
+  Serial.println();
+
+  delay(1000);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_read_RDY/ADS_read_RDY.ino b/examples/ADS_read_RDY/ADS_read_RDY.ino
new file mode 100644
index 0000000..fa84eb6
--- /dev/null
+++ b/examples/ADS_read_RDY/ADS_read_RDY.ino
@@ -0,0 +1,62 @@
+//
+//    FILE: ADS_read_RDY.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read analog inputs - straightforward.
+//
+
+// test
+// connect 1 potmeter per port.
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+//
+
+// EXPERIMENTAL
+//
+// The RDY pin (or ALERT Pin) is triggered when conversion is ready
+//
+
+#include "ADS1X15.h"
+
+ADS1115 ADS(0x48);
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);      // 6.144 volt
+  ADS.setDataRate(7);  // fast
+  ADS.setMode(1);      // continuous mode
+  ADS.readADC(0);      // first read to trigger
+  
+  // set the thresholds to Trigger RDY pin
+  ADS.setComparatorThresholdLow(0x0000);
+  ADS.setComparatorThresholdHigh(0x0200);
+  ADS.setComparatorQueConvert(0);             // enable RDY pin !!
+  ADS.setComparatorLatch(0);
+}
+
+void loop() 
+{
+  ADS.setGain(0);
+
+  int16_t val_0 = ADS.readADC(0);
+
+  float f = ADS.toVoltage(1);   // voltage factor
+
+  Serial.print("\tAnalog0: ");
+  Serial.print(val_0);
+  Serial.print('\t');
+  Serial.println(val_0 * f, 3);
+  
+  delay(1000);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_read_async/ADS_read_async.ino b/examples/ADS_read_async/ADS_read_async.ino
new file mode 100644
index 0000000..174f919
--- /dev/null
+++ b/examples/ADS_read_async/ADS_read_async.ino
@@ -0,0 +1,50 @@
+//
+//    FILE: ADS_read_async.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.1
+// PURPOSE: read analog inputs - asynchronous
+//
+
+// test
+// connect 1 potmeter per port.
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+//
+
+#include "ADS1X15.h"
+
+ADS1115 ADS(0x48);
+float f = 0;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);
+  f = ADS.toVoltage();      // voltage factor
+  ADS.requestADC(0);
+}
+
+void loop()
+{
+  if (ADS.isBusy() == false)
+  {
+    int16_t val_0 = ADS.getValue();
+    ADS.requestADC(0);  // request a new one
+    Serial.print("\tAnalog0: ");
+    Serial.print(val_0);
+    Serial.print('\t');
+    Serial.println(val_0 * f, 3);
+  }
+  // simulate other tasks...
+  delay(2000);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_read_async_rdy/ADS_read_async_rdy.ino b/examples/ADS_read_async_rdy/ADS_read_async_rdy.ino
new file mode 100644
index 0000000..9b04081
--- /dev/null
+++ b/examples/ADS_read_async_rdy/ADS_read_async_rdy.ino
@@ -0,0 +1,62 @@
+//
+//    FILE: ADS_read_async_rdy.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.1
+// PURPOSE: read analog inputs - straightforward.
+//
+
+// test
+// connect 1 potmeter per port.
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+//
+
+// EXPERIMENTAL
+//
+// The RDY pin (or ALERT Pin) is triggered when conversion is ready
+//
+
+#include "ADS1X15.h"
+
+ADS1115 ADS(0x48);
+float f = 0;
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+  ADS.setGain(0);      // 6.144 volt
+  ADS.setDataRate(0);  // slow so the led blinks visible for the eye.
+  f = ADS.toVoltage(); // voltage factor
+  ADS.requestADC(0);
+  
+  // set the thresholds to Trigger RDY pin
+  ADS.setComparatorThresholdLow(0x0000);
+  ADS.setComparatorThresholdHigh(0x0200);
+  ADS.setComparatorQueConvert(0);             // enable RDY pin !!
+  ADS.setComparatorLatch(0);
+}
+
+void loop() 
+{
+  if (ADS.isReady())
+  {
+    int16_t val_0 = ADS.getValue();
+    ADS.requestADC(0);  // request a new one
+    Serial.print("\tAnalog0: ");
+    Serial.print(val_0);
+    Serial.print('\t');
+    Serial.println(val_0 * f, 3);
+  }
+  // simulate other tasks...
+  delay(2000);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_read_comparator_1/ADS_read_comparator_1.ino b/examples/ADS_read_comparator_1/ADS_read_comparator_1.ino
new file mode 100644
index 0000000..e7315c1
--- /dev/null
+++ b/examples/ADS_read_comparator_1/ADS_read_comparator_1.ino
@@ -0,0 +1,82 @@
+//
+//    FILE: ADS_read_comparator_1.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read analog inputs - straightforward.
+//
+
+// test
+// connect 1 potmeter per port.
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+//
+// 
+// GND ---[LED]---[ALERT_PIN]---[ R ]--- 5V
+//
+// Connect a LED (+ resistor) to ALERT PIN
+// and see it trigger at configured way by the comparator.
+//
+
+
+#include "ADS1X15.h"
+
+ADS1115 ADS(0x48);
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+
+  // change if needed.
+  ADS.setComparatorMode(1);              // 0 = TRADITIONAL    1 = WINDOW
+
+  ADS.setComparatorPolarity(0);          // 0 = LOW (default)  1 = HIGH
+  
+  // note NON-LATCH gives only a short pulse
+  ADS.setComparatorLatch(1);             // 0 = NON LATCH      1 = LATCH
+
+  ADS.setComparatorQueConvert(0);        // 0 = trigger alert after 1 conversion
+
+  // set the thresholds as a number...
+  // ADS.setComparatorThresholdLow(5000);   // change if needed
+  // ADS.setComparatorThresholdHigh(20000); // change if needed
+
+  // set the threshold as a voltage by using the voltage factor.
+  float f = ADS.toVoltage(1);  // voltage factor
+  ADS.setComparatorThresholdLow(1.234 / f);   // convert volts to number needed
+  ADS.setComparatorThresholdHigh(3.142 / f);  // convert volts to number needed
+  
+  Serial.println(ADS.getComparatorThresholdLow());
+  Serial.println(ADS.getComparatorThresholdHigh());
+
+}
+
+void loop()
+{
+  ADS.setGain(0);
+
+  int16_t val_0 = ADS.readADC(0);
+
+  float f = ADS.toVoltage(1);  // voltage factor
+
+  Serial.print("\tAnalog0: ");
+  Serial.print(val_0);
+  Serial.print('\t');
+  Serial.print(val_0 * f, 3);
+  Serial.print('\t');
+  Serial.print(ADS.getComparatorThresholdLow() * f, 3);
+  Serial.print('\t');
+  Serial.print(ADS.getComparatorThresholdHigh() * f, 3);
+  Serial.println();
+
+  delay(100);
+}
+
+// -- END OF FILE --
diff --git a/examples/ADS_setWireClock/ADS_setWireClock.ino b/examples/ADS_setWireClock/ADS_setWireClock.ino
new file mode 100644
index 0000000..d2f0232
--- /dev/null
+++ b/examples/ADS_setWireClock/ADS_setWireClock.ino
@@ -0,0 +1,62 @@
+//
+//    FILE: ADS_setWireClock.ino
+//  AUTHOR: Rob.Tillaart
+// VERSION: 0.1.0
+// PURPOSE: read analog inputs - straightforward.
+//
+
+// test
+// connect 1 potmeter per port.
+//
+// GND ---[   x   ]------ 5V
+//            |
+//
+// measure at x (connect to AIN0).
+//
+
+#include "ADS1X15.h"
+
+ADS1115 ADS(0x48);
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  ADS.begin();
+
+  Serial.println(F("\nSET\tACTUAL\n=================="));
+  for (uint32_t speed = 50000; speed <= 1000000; speed += 50000)
+  {
+    ADS.setWireClock(speed);
+    Serial.print(speed);
+    Serial.print("\t");
+    Serial.println(ADS.getWireClock());
+  }
+  ADS.setWireClock(100000);
+  Serial.println();
+}
+
+void loop()
+{
+  ADS.setGain(0);
+
+  int16_t val_0 = ADS.readADC(0);
+  int16_t val_1 = ADS.readADC(1);
+  int16_t val_2 = ADS.readADC(2);
+  int16_t val_3 = ADS.readADC(3);
+
+  float f = ADS.toVoltage(1);  // voltage factor
+
+  Serial.print("\tAnalog0: "); Serial.print(val_0); Serial.print('\t'); Serial.println(val_0 * f, 3);
+  Serial.print("\tAnalog1: "); Serial.print(val_1); Serial.print('\t'); Serial.println(val_1 * f, 3);
+  Serial.print("\tAnalog2: "); Serial.print(val_2); Serial.print('\t'); Serial.println(val_2 * f, 3);
+  Serial.print("\tAnalog3: "); Serial.print(val_3); Serial.print('\t'); Serial.println(val_3 * f, 3);
+  Serial.println();
+
+  delay(1000);
+}
+
+// -- END OF FILE --
diff --git a/keywords.txt b/keywords.txt
new file mode 100644
index 0000000..f9f6801
--- /dev/null
+++ b/keywords.txt
@@ -0,0 +1,69 @@
+# Syntax Coloring Map For ADS1X15
+
+# Datatypes (KEYWORD1)
+ADS1X13	KEYWORD1
+ADS1014	KEYWORD1
+ADS1015	KEYWORD1
+ADS1015	KEYWORD1
+ADS1113	KEYWORD1
+ADS1114	KEYWORD1
+ADS1115	KEYWORD1
+
+
+# Methods and Functions (KEYWORD2)
+begin	KEYWORD2
+reset	KEYWORD2
+isBusy	KEYWORD2
+isReady()	KEYWORD2
+isConnected	KEYWORD2
+
+setGain	KEYWORD2
+getGain	KEYWORD2
+toVoltage	KEYWORD2
+getMaxVoltage	KEYWORD2
+setMode	KEYWORD2
+getMode	KEYWORD2
+setDataRate	KEYWORD2
+getDataRate	KEYWORD2
+
+readADC	KEYWORD2
+readADC_Differential_0_1	KEYWORD2
+readADC_Differential_0_3	KEYWORD2
+readADC_Differential_1_3	KEYWORD2
+readADC_Differential_2_3	KEYWORD2
+getValue	KEYWORD2
+
+setComparatorMode	KEYWORD2
+getComparatorMode	KEYWORD2
+setComparatorPolarity	KEYWORD2
+getComparatorPolarity	KEYWORD2
+setComparatorLatch	KEYWORD2
+getComparatorLatch	KEYWORD2
+setComparatorQueConvert	KEYWORD2
+getComparatorQueConvert	KEYWORD2
+setComparatorThresholdLow	KEYWORD2
+getComparatorThresholdLow	KEYWORD2
+setComparatorThresholdHigh	KEYWORD2
+getComparatorThresholdHigh	KEYWORD2
+
+getError	KEYWORD2
+setWireClock	KEYWORD2
+getWireClock	KEYWORD2
+
+# ASYNC INTERFACE
+
+requestADC	KEYWORD2
+requestADC_Differential_0_1	KEYWORD2
+requestADC_Differential_0_3	KEYWORD2
+requestADC_Differential_1_3	KEYWORD2
+requestADC_Differential_2_3	KEYWORD2
+
+
+# Constants (LITERAL1)
+ADS1X15_LIB_VERSION	LITERAL1
+ADS1X15_INVALID_VOLTAGE	LITERAL1
+ADS1X15_INVALID_GAIN	LITERAL1
+ADS1X15_INVALID_MODE	LITERAL1
+ADS1015_ADDRESS	LITERAL1
+ADS1115_ADDRESS	LITERAL1
+
diff --git a/library.json b/library.json
new file mode 100644
index 0000000..283be3a
--- /dev/null
+++ b/library.json
@@ -0,0 +1,23 @@
+{
+  "name": "ADS1X15",
+  "keywords": "ADS1013, ADS1014, ADS1015, ADS1113, ADS1114, ADS1115, I2C, ADC",
+  "description": "Arduino library for ADS1015 - I2C 12 bit ADC and ADS1115 I2C 16 bit ADC",
+  "authors":
+  [
+    {
+      "name": "Rob Tillaart",
+      "email": "Rob.Tillaart@gmail.com",
+      "maintainer": true
+    }
+  ],
+  "repository":
+  {
+    "type": "git",
+    "url": "https://github.com/RobTillaart/ADS1X15"
+  },
+  "version": "0.3.3",
+  "license": "MIT",
+  "frameworks": "*",
+  "platforms": "*",
+  "headers": "AD1x15.h"
+}
diff --git a/library.properties b/library.properties
new file mode 100644
index 0000000..7d44a46
--- /dev/null
+++ b/library.properties
@@ -0,0 +1,11 @@
+name=ADS1X15
+version=0.3.3
+author=Rob Tillaart <rob.tillaart@gmail.com>
+maintainer=Rob Tillaart <rob.tillaart@gmail.com>
+sentence=Arduino library for ADS1015 - I2C 12 bit ADC and ADS1115 I2C 16 bit ADC
+paragraph=Should work for ADS1013, ADS1014, ADS1113 and ADS1114
+category=Sensors
+url=https://github.com/RobTillaart/ADS1X15
+architectures=*
+includes=ADS1X15.h
+depends=
diff --git a/test/unit_test_001.cpp b/test/unit_test_001.cpp
new file mode 100644
index 0000000..0489204
--- /dev/null
+++ b/test/unit_test_001.cpp
@@ -0,0 +1,81 @@
+//
+//    FILE: unit_test_001.cpp
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.0
+//    DATE: 2020-12-03
+// PURPOSE: unit tests for the SHT31 temperature and humidity sensor
+//          https://github.com/RobTillaart/ADS1X15
+//
+
+// supported assertions
+// ----------------------------
+// assertEqual(expected, actual)
+// assertNotEqual(expected, actual)
+// assertLess(expected, actual)
+// assertMore(expected, actual)
+// assertLessOrEqual(expected, actual)
+// assertMoreOrEqual(expected, actual)
+// assertTrue(actual)
+// assertFalse(actual)
+// assertNull(actual)
+
+#include <ArduinoUnitTests.h>
+
+#include "Arduino.h"
+#include "ADS1X15.h"
+
+
+unittest_setup()
+{
+}
+
+unittest_teardown()
+{
+}
+
+unittest(test_begin)
+{
+  ADS1115 ADS(0x48);
+  assertTrue(ADS.begin());
+  assertTrue(ADS.isConnected());
+  assertTrue(ADS.isBusy());
+}
+
+unittest(test_gain)
+{
+  ADS1115 ADS(0x48);
+  assertTrue(ADS.begin());
+
+  assertEqual(0, ADS.getGain());
+  int gains[6] = { 0,1,2,4,8,16 };
+  for (int i = 0; i < 6; i++)
+  {
+    ADS.setGain(gains[i]);
+    assertEqual(gains[i], ADS.getGain());
+  }
+
+  ADS.setGain(42);
+  assertEqual(0, ADS.getGain());
+}
+
+unittest(test_Voltage)
+{
+  ADS1115 ADS(0x48);
+  assertTrue(ADS.begin());
+
+  // should test all values?
+  ADS.setGain(0);
+  float volts = ADS.getMaxVoltage();
+  float delta = abs(6.144 - volts);
+  assertMoreOrEqual(0.001, delta);
+
+  ADS.setGain(16);
+  volts = ADS.getMaxVoltage();
+  delta = abs(0.256 - volts);
+  assertMoreOrEqual(0.001, delta);
+}
+
+
+unittest_main()
+
+// --------