ADS1115 ADC driver with GPIO interrupt-based channel cycling. More...

#include <ads1115.hpp>

Collaboration diagram for Ads1115< CHANNEL_NUM >:

[legend]

Public Member Functions
	Ads1115 (I2cDevice &i2c, Gpio &drdy, uint8_t address=DEFAULT_I2C_ADDR)
	Constructor.

void	StartScan ()
	Starts scanning the channels and enabling data-ready interrupt.

void	Stop ()
	Stops the scan process.

float	GetVoltage (int channel) const
	Returns the latest voltage reading from a specific channel.

void	EnableReadyInterruptMode ()
	Registers interrupt-based data-ready mode (comparator configuration)

void	Display () const
	Prints voltage readings of all channels to console.

void	RegisterChannelCallback (int channel, std::function< void(float)> cb)
	Registers a callback function for a specific channel.

Static Public Attributes
static constexpr uint8_t	DEFAULT_I2C_ADDR = 0x48

static constexpr uint8_t	POINTER_CONVERSION = 0x00

static constexpr uint8_t	POINTER_CONFIG = 0x01

Private Member Functions
void	OnDataReady ()
	Called on rising edge of ALERT/RDY pin Reads current value, stores it, calls callback, then switches to next channel.

void	ConfigureChannel (int channel)
	Configures ADS1115 for a specific single-ended channel.

int16_t	ReadConversion ()
	Reads the 16-bit signed conversion result.

Private Attributes
I2cDevice &	i2c_

Gpio &	drdy_gpio_

uint8_t	i2c_addr_

std::function< void(float)>	callbacks_ [CHANNEL_NUM]

std::atomic< bool >	scanning_ {false}

int	current_channel_ = 0

float	voltages_ [CHANNEL_NUM] = {0.0f}

Detailed Description

template<int CHANNEL_NUM>
class Ads1115< CHANNEL_NUM >

ADS1115 ADC driver with GPIO interrupt-based channel cycling.

Continuously scans 4 single-ended channels using ALERT/RDY pin as data-ready signal, stores voltage values in voltages_[], and allows user-defined per-channel callbacks.

Definition at line 22 of file ads1115.hpp.

Constructor & Destructor Documentation

◆ Ads1115()

template<int CHANNEL_NUM>

Ads1115< CHANNEL_NUM >::Ads1115	(	I2cDevice &	i2c,
		Gpio &	drdy,
		uint8_t	address = `DEFAULT_I2C_ADDR`
	)

inline

Constructor.

Parameters

i2c	I2C device reference
drdy	GPIO for ALERT/RDY pin (interrupt-enabled)
address	I2C address (default 0x48)

Definition at line 34 of file ads1115.hpp.

      : i2c_(i2c), drdy_gpio_(drdy), i2c_addr_(address) {
    EnableReadyInterruptMode();
    StartScan();
  }

Member Function Documentation

◆ ConfigureChannel()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::ConfigureChannel ( int channel )

inlineprivate

Configures ADS1115 for a specific single-ended channel.

Parameters

channel Index 0~3

Definition at line 144 of file ads1115.hpp.

                                     {
    if (channel < 0 || channel > 3) {
      return;
    }
 
    uint16_t config = 0;
    config |= (0x04 + channel) << 12;  // MUX: AINx vs GND
    config |= (1 << 9);                // PGA ±4.096V
    config |= (0 << 8);                // Mode: Continuous
    config |= (0b111 << 5);            // Data Rate: 860 SPS
 
    uint8_t data[3] = {
        POINTER_CONFIG,
        static_cast<uint8_t>((config >> 8) & 0xFF),
        static_cast<uint8_t>(config & 0xFF),
    };
 
    i2c_.WriteRaw(data, 3);
 
    // Wait for config to take effect; discard first reading
    std::this_thread::sleep_for(std::chrono::milliseconds(1));
    ReadConversion();
  }

◆ Display()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::Display ( ) const

inline

Prints voltage readings of all channels to console.

Definition at line 85 of file ads1115.hpp.

                       {
    for (int i = 0; i < CHANNEL_NUM; ++i) {
      std::cout << "Channel " << i << ": " << voltages_[i] << " V  ";
    }
    std::cout << '\n';
  }

◆ EnableReadyInterruptMode()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::EnableReadyInterruptMode ( )

inline

Registers interrupt-based data-ready mode (comparator configuration)

Definition at line 72 of file ads1115.hpp.

                                  {
    // Set Lo_thresh = 0x0000 (MSB = 0)
    uint8_t lo_thresh[3] = {0x02, 0x00, 0x00};
    i2c_.WriteRaw(lo_thresh, 3);
 
    // Set Hi_thresh = 0x8000 (MSB = 1)
    uint8_t hi_thresh[3] = {0x03, 0x80, 0x00};
    i2c_.WriteRaw(hi_thresh, 3);
  }

◆ GetVoltage()

template<int CHANNEL_NUM>

float Ads1115< CHANNEL_NUM >::GetVoltage ( int channel ) const

inline

Returns the latest voltage reading from a specific channel.

Parameters

channel Index (0 ~ CHANNEL_NUM-1)

Returns: Voltage value in volts

Definition at line 62 of file ads1115.hpp.

                                      {
    if (channel < 0 || channel >= CHANNEL_NUM) {
      return 0.0f;
    }
    return voltages_[channel];
  }

◆ OnDataReady()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::OnDataReady ( )

inlineprivate

Called on rising edge of ALERT/RDY pin Reads current value, stores it, calls callback, then switches to next channel.

Definition at line 120 of file ads1115.hpp.

                     {
    if (!scanning_) {
      return;
    }
 
    // Read and convert voltage
    int16_t raw = ReadConversion();
    voltages_[current_channel_] =
        static_cast<float>(raw) * 0.000125f;  // 125 µV/LSB
 
    // Invoke user callback
    if (callbacks_[current_channel_]) {
      callbacks_[current_channel_](voltages_[current_channel_]);
    }
 
    // Switch to next channel
    current_channel_ = (current_channel_ + 1) % CHANNEL_NUM;
    ConfigureChannel(current_channel_);
  }

◆ ReadConversion()

template<int CHANNEL_NUM>

int16_t Ads1115< CHANNEL_NUM >::ReadConversion ( )

inlineprivate

Reads the 16-bit signed conversion result.

Returns: ADC result (LSB = 125 µV at ±4.096V)

Definition at line 172 of file ads1115.hpp.

                           {
    uint8_t pointer = POINTER_CONVERSION;
    i2c_.WriteRaw(&pointer, 1);
 
    uint8_t buf[2] = {};
    i2c_.ReadRegisters(POINTER_CONVERSION, buf, 2);
 
    return static_cast<int16_t>((buf[0] << 8) | buf[1]);
  }

◆ RegisterChannelCallback()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::RegisterChannelCallback	(	int	channel,
		std::function< void(float)>	cb
	)

inline

Registers a callback function for a specific channel.

Parameters

channel	Index (0 ~ CHANNEL_NUM-1)
cb	Callback function taking float voltage as parameter

Definition at line 97 of file ads1115.hpp.

                                                                         {
    if (channel >= 0 && channel < CHANNEL_NUM) {
      callbacks_[channel] = cb;
    }
  }

◆ StartScan()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::StartScan ( )

inline

Starts scanning the channels and enabling data-ready interrupt.

Definition at line 43 of file ads1115.hpp.

                   {
    scanning_ = true;
    current_channel_ = 0;
    ConfigureChannel(current_channel_);
 
    drdy_gpio_.EnableInterruptRisingEdgeWithCallback(
        [this]() { OnDataReady(); });
  }

◆ Stop()

template<int CHANNEL_NUM>

void Ads1115< CHANNEL_NUM >::Stop ( )

inline

Stops the scan process.

Definition at line 55 of file ads1115.hpp.

55{ scanning_ = false; }

Field Documentation

◆ callbacks_

template<int CHANNEL_NUM>

std::function<void(float)> Ads1115< CHANNEL_NUM >::callbacks_[CHANNEL_NUM]

private

Definition at line 109 of file ads1115.hpp.

◆ current_channel_

template<int CHANNEL_NUM>

int Ads1115< CHANNEL_NUM >::current_channel_ = 0

private

Definition at line 112 of file ads1115.hpp.

◆ DEFAULT_I2C_ADDR

template<int CHANNEL_NUM>

constexpr uint8_t Ads1115< CHANNEL_NUM >::DEFAULT_I2C_ADDR = 0x48

staticconstexpr

Definition at line 24 of file ads1115.hpp.

◆ drdy_gpio_

template<int CHANNEL_NUM>

Gpio& Ads1115< CHANNEL_NUM >::drdy_gpio_

private

Definition at line 107 of file ads1115.hpp.

◆ i2c_

template<int CHANNEL_NUM>

I2cDevice& Ads1115< CHANNEL_NUM >::i2c_

private

Definition at line 105 of file ads1115.hpp.

◆ i2c_addr_

template<int CHANNEL_NUM>

uint8_t Ads1115< CHANNEL_NUM >::i2c_addr_

private

Definition at line 108 of file ads1115.hpp.

◆ POINTER_CONFIG

template<int CHANNEL_NUM>

constexpr uint8_t Ads1115< CHANNEL_NUM >::POINTER_CONFIG = 0x01

staticconstexpr

Definition at line 26 of file ads1115.hpp.

◆ POINTER_CONVERSION

template<int CHANNEL_NUM>

constexpr uint8_t Ads1115< CHANNEL_NUM >::POINTER_CONVERSION = 0x00

staticconstexpr

Definition at line 25 of file ads1115.hpp.

◆ scanning_

template<int CHANNEL_NUM>

std::atomic<bool> Ads1115< CHANNEL_NUM >::scanning_ {false}

private

Definition at line 111 of file ads1115.hpp.

111{false};

◆ voltages_

template<int CHANNEL_NUM>

float Ads1115< CHANNEL_NUM >::voltages_[CHANNEL_NUM] = {0.0f}

private

Definition at line 113 of file ads1115.hpp.

113{0.0f};

The documentation for this class was generated from the following file:

src/device/ads1115.hpp

Public Member Functions

Static Public Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Ads1115()

Member Function Documentation

◆ ConfigureChannel()

◆ Display()

◆ EnableReadyInterruptMode()

◆ GetVoltage()

◆ OnDataReady()

◆ ReadConversion()

◆ RegisterChannelCallback()

◆ StartScan()

◆ Stop()

Field Documentation

◆ callbacks_

◆ current_channel_

◆ DEFAULT_I2C_ADDR

◆ drdy_gpio_

◆ i2c_

◆ i2c_addr_

◆ POINTER_CONFIG

◆ POINTER_CONVERSION

◆ scanning_

◆ voltages_