INA228 Driver

Platform-independent C99 driver for the TI INA228 — an 85 V, 20-bit power/energy/charge monitor with an I2C interface. (DATASHEET)

Portability comes from using a generic void *ctx pointer, which represents the platform-specific context used to access the I²C peripheral. The driver never interprets ctx directly—it simply passes it to the platform-specific I²C read/write functions.

Typical contexts:

• STM32: I2C_HandleTypeDef *
• Linux: an I2C file descriptor (usually wrapped in a small struct)
• ESP-IDF: i2c_master_bus_handle_t

Layout

Path	Contents
inc/	Public header (ina228.h)
src/	Driver implementation (ina228.c)
tests/	Host-side unit tests (mock I2C bus)
examples/	Platform port examples

Requirements

• CMake ≥ 3.15
• A C99 compiler (GCC/Clang/MSVC)

Build & Test

cmake -S . -B build
cmake --build build
ctest --test-dir build --output-on-failure

On Windows with MSYS2/MinGW, pass a generator: -G "MinGW Makefiles".

Run the test binary directly (add .exe on Windows):

./build/test_ina228

Remove compiled objects but keep the CMake cache with cmake --build build --target clean; delete build/ entirely for a clean rebuild.

Using the Driver

Option 1: CMake Subdirectory

Copy the ina228_driver folder into your project, then in your top-level CMakeLists.txt:

add_subdirectory(ina228_driver)
target_link_libraries(your_target PRIVATE ina228)

Option 2: Without CMake

Add src/ina228.c to your source list and inc/ to your include paths.

Wiring Up the Driver

1. Implement ina228_i2c_read_fn, ina228_i2c_write_fn, and ina228_delay_ms_fn for your platform.
2. Fill in an ina228_t descriptor (callbacks, ctx, dev_addr, shunt_resistor, max_current).
3. Call ina228_init(), then read measurements.

#include "ina228.h"

ina228_t dev = { /* callbacks, ctx, dev_addr, shunt_resistor, max_current */ };
ina228_init(&dev);

float voltage, current, power;
ina228_read_voltage(&dev, &voltage);
ina228_read_current(&dev, &current);
ina228_read_power(&dev, &power);

See inc/ina228.h for the full API.

NOTE: The public header is wrapped in extern "C", so it can be included directly from C++ sources.