Library for the ADS1015 and ADS1115 ADCS
Fork of ADS1015 by
Adafruit_ADS1015.cpp
- Committer:
- DEldering
- Date:
- 2017-06-12
- Revision:
- 8:bf2e64504294
- Parent:
- 6:e6fecdc96fb1
- Child:
- 9:fc08929a1093
- Child:
- 10:da5d0da65437
File content as of revision 8:bf2e64504294:
/**************************************************************************/ /*! @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_3300SPS | // 860(ADS1115) samples per second 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_us(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; return 1; } /**************************************************************************/ /*! @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(ADS1015) or 250(ADS1115) 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(ADS1015) or 250(ADS1115) 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(ADS1015) or 250(ADS1115) 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; } }