Module ina226 

Texas Instruments INA226 high-side or low-side current, voltage, and power monitor.

The INA226 measures the voltage across a shunt resistor and the bus voltage on common-mode voltages from 0 V to 36 V and, once its calibration register is programmed, computes current and power on the chip. It adds programmable conversion times and averaging, and an alert pin driven by a single limit register. This module builds the calibration and configuration values and decodes each register into a physical quantity, following the datasheet’s equations and its worked example, so a battery-balancer or rack-power node reads amps and watts directly.

Shunt voltages are returned in nanovolts, bus voltages in microvolts, and current and power in microamps and microwatts, so the 2.5 µV and 1.25 mV register LSBs convert exactly without floating point. f32 conveniences sit beside them.

Modules

register

The INA226 register pointer addresses.

Structs

Configuration

The configuration register (0x00), decoded into its fields.

DieId

The die ID register (0xFF), split into its device and revision fields.

MaskEnable

The Mask/Enable register (0x06): which alert function drives the pin, how the pin behaves, and the status flags the chip reports back.

Enums

AddressPin

What an address pin is tied to; each of A1 and A0 takes one of four levels.

AlertFunction

The five limit comparisons the alert pin can be assigned to.

Averaging

The number of samples the ADC averages before updating the result registers.

ConversionTime

The ADC conversion time for one shunt or bus voltage measurement.

Mode

The operating mode: which inputs are converted, and whether once or continuously.

Constants

BASE_ADDRESS

The base I2C address, selected when both address pins are tied to ground.

BUS_LSB_MICROVOLTS

The bus voltage register LSB, 1.25 mV, in microvolts.

CONFIG_RESET

The power-on value of the configuration register (0x4127): averaging off, 1.1 ms conversion time for both bus and shunt, and continuous shunt-and-bus conversion.

DEVICE_ID

The 12-bit device ID carried in bits 15:4 of the die ID register.

MANUFACTURER_ID

The value the manufacturer ID register always reads (0x5449, “TI”).

POWER_LSB_RATIO

The fixed ratio between the power LSB and the programmed current LSB.

SHUNT_LSB_NANOVOLTS

The shunt voltage register LSB, 2.5 µV, in nanovolts.

Functions

address

Returns the 7-bit I2C address selected by the A1 and A0 pins.

bus_microvolts

Decodes the bus voltage register to microvolts.

bus_register

Builds the bus voltage register a monitor reports for a bus voltage.

bus_volts_f32

Decodes the bus voltage register to volts as a float.

calibration

Computes the calibration register value for a chosen current resolution and shunt.

current_amps_f32

Decodes the current register to amps as a float.

current_microamps

Decodes the current register to microamps for a given current LSB.

current_register

Builds the current register a monitor reports for a current.

current_register_from_shunt

Reproduces the chip’s current calculation from a shunt reading and calibration.

identify

Checks that the identification registers belong to an INA226.

minimum_current_lsb_microamps

Returns the smallest current LSB, in microamps, that still spans a full-scale current.

power_microwatts

Decodes the power register to microwatts for a given current LSB.

power_register

Builds the power register a monitor reports for a power.

power_register_from_current

Reproduces the chip’s power calculation from the current and bus registers.

power_watts_f32

Decodes the power register to watts as a float.

shunt_millivolts_f32

Decodes the shunt voltage register to millivolts as a float.

shunt_nanovolts

Decodes the shunt voltage register to nanovolts.

shunt_register

Builds the shunt voltage register a monitor reports for a shunt voltage.