Diff: Adafruit_ADS1015.cpp

Revision:

0:8174d9ceeca1

Child:

2:d864e21d4e58

Child:

3:fb735fb343de

diff -r 000000000000 -r 8174d9ceeca1 Adafruit_ADS1015.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_ADS1015.cpp	Sun Nov 10 18:22:27 2013 +0000
@@ -0,0 +1,336 @@
+/**************************************************************************/
+/*!
+    @file     Adafruit_ADS1015.cpp
+    @author   K.Townsend (Adafruit Industries)
+    @license  BSD (see LICENSE.txt)
+
+    Ported to mbed by Arve Seljebu - arve0.github.io
+
+    Driver for the ADS1015/ADS1115 ADC
+
+    This is a library for the Adafruit MPL115A2 breakout
+    ----> https://www.adafruit.com/products/1083
+
+    Adafruit invests time and resources providing this open source code,
+    please support Adafruit and open-source hardware by purchasing
+    products from Adafruit!
+
+    @section  HISTORY
+
+    v1.0 - First release
+    v1.1.1 - Ported to mbed
+*/
+/**************************************************************************/
+
+#include <mbed.h>
+#include "Adafruit_ADS1015.h"
+
+/**************************************************************************/
+/*!
+    @brief  Writes 16-bits to the specified destination register
+*/
+/**************************************************************************/
+void Adafruit_ADS1015::writeRegister(uint8_t i2cAddress, uint8_t reg, uint16_t value) {
+  char cmd[3];
+  cmd[0] = (char)reg;
+  cmd[1] = (char)(value>>8);
+  cmd[2] = (char)(value & 0xFF);
+  m_i2c->write(i2cAddress, cmd, 3); 
+}
+
+/**************************************************************************/
+/*!
+    @brief  Reads 16-bits from the specified register
+*/
+/**************************************************************************/
+uint16_t Adafruit_ADS1015::readRegister(uint8_t i2cAddress, uint8_t reg) {
+  char data[2];
+  data[0] = reg; // temporary use this to send address to conversion register
+  m_i2c->write(i2cAddress, data, 1);
+  m_i2c->read(i2cAddress, data, 2);
+  return (data[0] << 8 | data [1]);
+}
+
+/**************************************************************************/
+/*!
+    @brief  Instantiates a new ADS1015 class w/appropriate properties
+*/
+/**************************************************************************/
+Adafruit_ADS1015::Adafruit_ADS1015(I2C* i2c, uint8_t i2cAddress) 
+{
+  // shift 7 bit address 1 left: read expects 8 bit address, see I2C.h
+   m_i2cAddress = i2cAddress << 1;
+   m_conversionDelay = ADS1015_CONVERSIONDELAY;
+   m_bitShift = 4;
+   m_gain = GAIN_TWOTHIRDS; /* +/- 6.144V range (limited to VDD +0.3V max!) */
+   m_i2c = i2c;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Instantiates a new ADS1115 class w/appropriate properties
+*/
+/**************************************************************************/
+Adafruit_ADS1115::Adafruit_ADS1115(I2C* i2c, uint8_t i2cAddress)
+{
+  // shift 7 bit address 1 left: read expects 8 bit address, see mbed's I2C.h
+  m_i2cAddress = i2cAddress << 1;
+  m_conversionDelay = ADS1115_CONVERSIONDELAY;
+  m_bitShift = 0;
+  m_gain = GAIN_TWOTHIRDS; /* +/- 6.144V range (limited to VDD +0.3V max!) */
+  m_i2c = i2c;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Sets the gain and input voltage range
+*/
+/**************************************************************************/
+void Adafruit_ADS1015::setGain(adsGain_t gain)
+{
+  m_gain = gain;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Gets a gain and input voltage range
+*/
+/**************************************************************************/
+adsGain_t Adafruit_ADS1015::getGain()
+{
+  return m_gain;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Gets a single-ended ADC reading from the specified channel
+*/
+/**************************************************************************/
+uint16_t Adafruit_ADS1015::readADC_SingleEnded(uint8_t channel) {
+  if (channel > 3)
+  {
+    return 0;
+  }
+  
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE    | // Disable the comparator (default val)
+                    ADS1015_REG_CONFIG_CLAT_NONLAT  | // Non-latching (default val)
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_SINGLE;   // Single-shot mode (default)
+
+  // Set PGA/voltage range
+  config |= m_gain;
+
+  // Set single-ended input channel
+  switch (channel)
+  {
+    case (0):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_0;
+      break;
+    case (1):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_1;
+      break;
+    case (2):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_2;
+      break;
+    case (3):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_3;
+      break;
+  }
+
+  // Set 'start single-conversion' bit
+  config |= ADS1015_REG_CONFIG_OS_SINGLE;
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  // Shift 12-bit results right 4 bits for the ADS1015
+  return readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;  
+}
+
+/**************************************************************************/
+/*! 
+    @brief  Reads the conversion results, measuring the voltage
+            difference between the P (AIN0) and N (AIN1) input.  Generates
+            a signed value since the difference can be either
+            positive or negative.
+*/
+/**************************************************************************/
+int16_t Adafruit_ADS1015::readADC_Differential_0_1() {
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE    | // Disable the comparator (default val)
+                    ADS1015_REG_CONFIG_CLAT_NONLAT  | // Non-latching (default val)
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_SINGLE;   // Single-shot mode (default)
+
+  // Set PGA/voltage range
+  config |= m_gain;
+                    
+  // Set channels
+  config |= ADS1015_REG_CONFIG_MUX_DIFF_0_1;          // AIN0 = P, AIN1 = N
+
+  // Set 'start single-conversion' bit
+  config |= ADS1015_REG_CONFIG_OS_SINGLE;
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
+}
+
+/**************************************************************************/
+/*! 
+    @brief  Reads the conversion results, measuring the voltage
+            difference between the P (AIN2) and N (AIN3) input.  Generates
+            a signed value since the difference can be either
+            positive or negative.
+*/
+/**************************************************************************/
+int16_t Adafruit_ADS1015::readADC_Differential_2_3() {
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE    | // Disable the comparator (default val)
+                    ADS1015_REG_CONFIG_CLAT_NONLAT  | // Non-latching (default val)
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_SINGLE;   // Single-shot mode (default)
+
+  // Set PGA/voltage range
+  config |= m_gain;
+
+  // Set channels
+  config |= ADS1015_REG_CONFIG_MUX_DIFF_2_3;          // AIN2 = P, AIN3 = N
+
+  // Set 'start single-conversion' bit
+  config |= ADS1015_REG_CONFIG_OS_SINGLE;
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
+}
+
+/**************************************************************************/
+/*!
+    @brief  Sets up the comparator to operate in basic mode, causing the
+            ALERT/RDY pin to assert (go from high to low) when the ADC
+            value exceeds the specified threshold.
+
+            This will also set the ADC in continuous conversion mode.
+*/
+/**************************************************************************/
+void Adafruit_ADS1015::startComparator_SingleEnded(uint8_t channel, int16_t threshold)
+{
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_1CONV   | // Comparator enabled and asserts on 1 match
+                    ADS1015_REG_CONFIG_CLAT_LATCH   | // Latching mode
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_CONTIN  | // Continuous conversion mode
+                    ADS1015_REG_CONFIG_MODE_CONTIN;   // Continuous conversion mode
+
+  // Set PGA/voltage range
+  config |= m_gain;
+                    
+  // Set single-ended input channel
+  switch (channel)
+  {
+    case (0):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_0;
+      break;
+    case (1):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_1;
+      break;
+    case (2):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_2;
+      break;
+    case (3):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_3;
+      break;
+  }
+
+  // Set the high threshold register
+  // Shift 12-bit results left 4 bits for the ADS1015
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_HITHRESH, threshold << m_bitShift);
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+}
+
+/**************************************************************************/
+/*!
+    @brief  In order to clear the comparator, we need to read the
+            conversion results.  This function reads the last conversion
+            results without changing the config value.
+*/
+/**************************************************************************/
+int16_t Adafruit_ADS1015::getLastConversionResults()
+{
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
+}