Welcome to Ziv Low’s INA226 documentation!

This library component provides an easier way to use the INA226 power monitor IC. This C++ library is written specifically for the ESP-IDF platform (at least ESP-IDF v5.2).

Take a look at the provided example code for inspiration on how to use this library.

Indices and tables

API

class INA226 : public INA226_Driver

Represents an INA226 device for current and power monitoring.

This class provides an interface for interacting with the INA226 device over I2C communication. It allows initializing the I2C bus, writing to and reading from the device registers, and handling I2C-related errors.

Public Functions

INA226(const gpio_num_t sda_io_num = static_cast<gpio_num_t>(CONFIG_I2C_MASTER_SDA), const gpio_num_t scl_io_num = static_cast<gpio_num_t>(CONFIG_I2C_MASTER_SCL), const uint16_t address = CONFIG_INA226_I2C_ADDRESS, const uint32_t scl_frequency = CONFIG_I2C_MASTER_FREQUENCY, const i2c_port_num_t i2c_port_num = static_cast<i2c_port_num_t>(CONFIG_I2C_MASTER_PORT_NUM))

Initializes the I2C of ESP-IDF.

Parameters:
  • sda_io_num[in] GPIO number of SDA pin. Defaults to GPIO 21 for ESP32.

  • scl_io_num[in] GPIO number of SCL pin. Defaults to GPIO 22 for ESP32.

  • address[in] I2C address of INA226. Defaults to 0x40.

  • scl_frequency[in] Frequency of SCL pin. Defaults to 100000.

  • i2c_port_num[in] I2C port number.

class INA226_Driver

INA226 driver class for controlling and accessing the INA226 power monitor IC.

The INA226_Driver class provides a set of functions to initialize the INA226, read various measurements, and configure its operating modes, averaging modes, conversion times, and alert triggers.

This class is designed to be inherited and implemented by a specific I2C driver for the target platform. The I2C_Write and I2C_Read functions are abstract and need to be implemented by the derived class.

Note

The INA226 is a power monitor IC that can measure shunt voltage, bus voltage, current, and power. It also supports various operating modes, averaging modes, and conversion times.

Note

The INA226_Driver class uses the std::expected type to handle errors and return values. If an error occurs, a std::runtime_error is returned with an error message.

Note

The INA226_Driver class is not thread-safe and should be used in a single-threaded environment.

Subclassed by INA226

Getters

int32_t GetShuntVoltage_uV()

Get the Shunt Voltage in micro-Volts.

Returns:

int32_t

int32_t GetBusVoltage_mV()

Get the Bus Voltage in milli-Volts.

Returns:

int32_t

int32_t GetCurrent_uA()

Get the Current in micro-Amps.

Returns:

int32_t

int32_t GetPower_uW()

Get the Power in micro-Watts.

Returns:

int32_t

uint16_t GetConfig()

Get the configuration register value.

Returns:

uint16_t

uint16_t GetManufacturerID()

Get the manufacturer ID.

Returns:

uint16_t

uint16_t GetDieID()

Get the die ID.

Returns:

uint16_t

OperatingMode GetOperatingMode()

Get the operating mode.

Returns:

OperatingMode

AveragingMode GetAveragingMode()

Get the averaging mode.

Returns:

AveragingMode

ConversionTime GetBusVoltageConversionTime()

Get the bus voltage conversion time.

Returns:

ConversionTime

ConversionTime GetShuntVoltageConversionTime()

Get the shunt voltage conversion time.

Returns:

ConversionTime

uint16_t GetAlertTriggerMask()

Get the alert trigger mask.

Returns:

uint16_t

uint16_t GetAlertLimitValue()

Get the alert limit value.

Returns:

uint16_t

Setters

void Reset()

Reset the INA226.

void Calibrate(const uint32_t ShuntResistor_mOhm = 100, const uint32_t MaxCurrent_A = 1)

Calibrate the INA226.

Note

Max current is limited by the value of shunt resistor. 0.1ohm shunt can measure up to (2^15 -1)* 2.5µV / 0.1ohm = 819175µA (=0.819175A)

Parameters:
  • ShuntResistor_mOhm[in] Shunt resistor value in milli-Ohms. Defaults to 100mOhm.

  • MaxCurrent_A[in] Maximum current in Amps. Defaults to 1A.

void SetConfig(const uint16_t Config)

Set the configuration register value.

Parameters:

Config[in] The configuration register value.

void SetOperatingMode(OperatingMode Mode)

Set the operating mode.

Parameters:

Mode[in] The operating mode.

void SetAveragingMode(AveragingMode Mode)

Set the averaging mode.

Parameters:

Mode[in] The averaging mode.

void SetBusVoltageConversionTime(ConversionTime Time)

Set the bus voltage conversion time.

Parameters:

Time[in] The bus voltage conversion time.

void SetShuntVoltageConversionTime(ConversionTime Time)

Set the shunt voltage conversion time.

Parameters:

Time[in] The shunt voltage conversion time.

void SetAlertTriggerMask(AlertTriggerMask AlertTriggerMask)

Set the alert trigger mask.

Note

If multiple functions are enabled, the highest significant bit position Alert Function (D15-D11) takes priority and responds to the Alert Limit Register.

Parameters:

AlertTriggerMask[in] The alert trigger mask.

void SetAlertLimitValue(uint16_t AlertLimitValue)

Set the alert limit value.

Parameters:

AlertLimitValue[in] The alert limit value.

Public Types

enum class Const : uint16_t

Values:

enumerator BUS_VOLTAGE_LSB_uV
enumerator SHUNT_VOLTAGE_LSB_nV
enumerator POWER_LSB_FACTOR
enumerator CONFIG_RESET_VALUE
enum class Register : uint8_t

Values:

enumerator CONFIGURATION
enumerator SHUNT_VOLTAGE
enumerator BUS_VOLTAGE
enumerator POWER
enumerator CURRENT
enumerator CALIBRATION
enumerator MASK_ENABLE
enumerator ALERT_LIMIT
enumerator MANUFACTURER_ID
enumerator DIE_ID
enum class ConfigMask : uint16_t

Values:

enumerator OPERATING_MODE
enumerator SHUNT_VOLTAGE_CONVERSION_TIME
enumerator BUS_VOLTAGE_CONVERSION_TIME
enumerator AVERAGING_MODE
enumerator RESET
enum class ConfigOffset : uint8_t

Values:

enumerator OPERATING_MODE
enumerator SHUNT_VOLTAGE_CONVERSION_TIME
enumerator BUS_VOLTAGE_CONVERSION_TIME
enumerator AVERAGING_MODE
enumerator RESET
enum class OperatingMode : uint8_t

Operating modes of INA226.

Select continuous, triggered, or power-down mode of operation. Defaults to continuous shunt and bus measurement mode.

Values:

enumerator POWER_DOWN

Power-down mode.

enumerator SHUNT_VOLTAGE_TRIGGERED

Shunt voltage triggered mode.

enumerator BUS_VOLTAGE_TRIGGERED

Bus voltage triggered mode.

enumerator SHUNT_AND_BUS_TRIGGERED

Shunt and bus voltage triggered mode.

enumerator ADC_OFF

ADC off mode.

enumerator SHUNT_VOLTAGE_CONTINUOUS

Continuous shunt voltage measurement mode.

enumerator BUS_VOLTAGE_CONTINUOUS

Continuous bus voltage measurement mode.

enumerator SHUNT_AND_BUS_CONTINUOUS

Continuous shunt and bus voltage measurement mode.

enum class AveragingMode : uint8_t

Averaging modes of INA226.

Select the number of samples to be averaged. Defaults to 1 sample.

Values:

enumerator SAMPLE_1

1 sample

enumerator SAMPLE_4

4 samples

enumerator SAMPLE_16

16 samples

enumerator SAMPLE_64

64 samples

enumerator SAMPLE_128

128 samples

enumerator SAMPLE_256

256 samples

enumerator SAMPLE_512

512 samples

enumerator SAMPLE_1024

1024 samples

enum class ConversionTime : uint8_t

Conversion times of INA226.

Select the conversion time for shunt and bus voltage measurements. Defaults to 1100us (=1.1ms).

Values:

enumerator TIME_140_uS

140 microseconds

enumerator TIME_204_uS

204 microseconds

enumerator TIME_332_uS

332 microseconds

enumerator TIME_588_uS

588 microseconds

enumerator TIME_1100_uS

1100 microseconds

enumerator TIME_2116_uS

2116 microseconds

enumerator TIME_4156_uS

4156 microseconds

enumerator TIME_8244_uS

8244 microseconds

enum class AlertTriggerMask : uint16_t

Alert trigger masks of INA226.

Select the alert trigger masks. Defaults to all disabled (Transparent mode).

Values:

enumerator SHUNT_OVER_VOLTAGE

Shunt over-voltage trigger mask.

enumerator SHUNT_UNDER_VOLTAGE

Shunt under-voltage trigger mask.

enumerator BUS_OVER_VOLTAGE

Bus over-voltage trigger mask.

enumerator BUS_UNDER_VOLTAGE

Bus under-voltage trigger mask.

enumerator POWER_OVER_LIMIT

Power over-limit trigger mask.

enumerator CONVERSION_READY

Conversion ready trigger mask.

enumerator ALERT_FUNCTION_FLAG

Alert function flag trigger mask.

enumerator CONVERSION_READY_FLAG

Conversion ready flag trigger mask.

enumerator MATH_OVERFLOW_FLAG

Math overflow flag trigger mask.

enumerator ALERT_POLARITY

Alert polarity trigger mask.

enumerator ALERT_LATCH_ENABLE

Alert latch enable trigger mask.

enumerator ERROR

Error trigger mask.

Public Functions

std::expected<void, std::runtime_error> InitDriver(const uint32_t ShuntResistor_mOhm = CONFIG_INA226_SHUNT_RESISTOR_MILLIOHMS, const uint32_t MaxCurrent_A = CONFIG_INA226_MAX_CURRENT_AMPS)

Initializes the INA226 driver.

Parameters:
  • ShuntResistor_mOhm[in] Shunt resistor value in milli-Ohms. Defaults to 100mOhm.

  • MaxCurrent_A[in] Maximum current in Amps. Defaults to 1A.

Returns:

std::expected<void, std::runtime_error>