ina226.cpp

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#include "ina226.h"
#include "esphome/core/log.h"
#include "esphome/core/hal.h"
#include <cinttypes>
 
namespace esphome::ina226 {
 
static const char *const TAG = "ina226";
 
// | A0   | A1   | Address |
// | GND  | GND  | 0x40    |
// | GND  | V_S+ | 0x41    |
// | GND  | SDA  | 0x42    |
// | GND  | SCL  | 0x43    |
// | V_S+ | GND  | 0x44    |
// | V_S+ | V_S+ | 0x45    |
// | V_S+ | SDA  | 0x46    |
// | V_S+ | SCL  | 0x47    |
// | SDA  | GND  | 0x48    |
// | SDA  | V_S+ | 0x49    |
// | SDA  | SDA  | 0x4A    |
// | SDA  | SCL  | 0x4B    |
// | SCL  | GND  | 0x4C    |
// | SCL  | V_S+ | 0x4D    |
// | SCL  | SDA  | 0x4E    |
// | SCL  | SCL  | 0x4F    |
 
static const uint8_t INA226_REGISTER_CONFIG = 0x00;
static const uint8_t INA226_REGISTER_SHUNT_VOLTAGE = 0x01;
static const uint8_t INA226_REGISTER_BUS_VOLTAGE = 0x02;
static const uint8_t INA226_REGISTER_POWER = 0x03;
static const uint8_t INA226_REGISTER_CURRENT = 0x04;
static const uint8_t INA226_REGISTER_CALIBRATION = 0x05;
 
static const uint16_t INA226_ADC_TIMES[] = {140, 204, 332, 588, 1100, 2116, 4156, 8244};
static const uint16_t INA226_ADC_AVG_SAMPLES[] = {1, 4, 16, 64, 128, 256, 512, 1024};
 
void INA226Component::setup() {
  ConfigurationRegister config;
 
  config.reset = 1;
  if (!this->write_byte_16(INA226_REGISTER_CONFIG, config.raw)) {
    this->mark_failed();
    return;
  }
  delay(1);
 
  config.raw = 0;
  config.reserved = 0b100;  // as per datasheet
 
  // Averaging Mode AVG Bit Settings[11:9] (000 -> 1 sample, 001 -> 4 sample, 111 -> 1024 samples)
  config.avg_samples = this->adc_avg_samples_;
 
  // Bus Voltage Conversion Time VBUSCT Bit Settings [8:6] (100 -> 1.1ms, 111 -> 8.244 ms)
  config.bus_voltage_conversion_time = this->adc_time_voltage_;
 
  // Shunt Voltage Conversion Time VSHCT Bit Settings [5:3] (100 -> 1.1ms, 111 -> 8.244 ms)
  config.shunt_voltage_conversion_time = this->adc_time_current_;
 
  // Mode Settings [2:0] Combinations (111 -> Shunt and Bus, Continuous)
  config.mode = 0b111;
 
  if (!this->write_byte_16(INA226_REGISTER_CONFIG, config.raw)) {
    this->mark_failed();
    return;
  }
 
  // lsb is multiplied by 1000000 to store it as an integer value
  uint32_t lsb = static_cast<uint32_t>(ceilf(this->max_current_a_ * 1000000.0f / 32768));
 
  this->calibration_lsb_ = lsb;
 
  auto calibration = uint32_t(0.00512 / (lsb * this->shunt_resistance_ohm_ / 1000000.0f));
 
  ESP_LOGV(TAG, "    Using LSB=%" PRIu32 " calibration=%" PRIu32, lsb, calibration);
 
  if (!this->write_byte_16(INA226_REGISTER_CALIBRATION, calibration)) {
    this->mark_failed();
    return;
  }
}
 
void INA226Component::dump_config() {
  ESP_LOGCONFIG(TAG, "INA226:");
  LOG_I2C_DEVICE(this);
 
  if (this->is_failed()) {
    ESP_LOGE(TAG, ESP_LOG_MSG_COMM_FAIL);
    return;
  }
  LOG_UPDATE_INTERVAL(this);
 
  ESP_LOGCONFIG(TAG,
                "  ADC Conversion Time Bus Voltage: %d\n"
                "  ADC Conversion Time Shunt Voltage: %d\n"
                "  ADC Averaging Samples: %d",
                INA226_ADC_TIMES[this->adc_time_voltage_ & 0b111], INA226_ADC_TIMES[this->adc_time_current_ & 0b111],
                INA226_ADC_AVG_SAMPLES[this->adc_avg_samples_ & 0b111]);
 
  LOG_SENSOR("  ", "Bus Voltage", this->bus_voltage_sensor_);
  LOG_SENSOR("  ", "Shunt Voltage", this->shunt_voltage_sensor_);
  LOG_SENSOR("  ", "Current", this->current_sensor_);
  LOG_SENSOR("  ", "Power", this->power_sensor_);
}
 
void INA226Component::update() {
  if (this->bus_voltage_sensor_ != nullptr) {
    uint16_t raw_bus_voltage;
    if (!this->read_byte_16(INA226_REGISTER_BUS_VOLTAGE, &raw_bus_voltage)) {
      this->status_set_warning();
      return;
    }
    // Convert for 2's compliment and signed value (though always positive)
    float bus_voltage_v = this->twos_complement_(raw_bus_voltage, 16);
    bus_voltage_v *= 0.00125f;
    this->bus_voltage_sensor_->publish_state(bus_voltage_v);
  }
 
  if (this->shunt_voltage_sensor_ != nullptr) {
    uint16_t raw_shunt_voltage;
    if (!this->read_byte_16(INA226_REGISTER_SHUNT_VOLTAGE, &raw_shunt_voltage)) {
      this->status_set_warning();
      return;
    }
    // Convert for 2's compliment and signed value
    float shunt_voltage_v = this->twos_complement_(raw_shunt_voltage, 16);
    shunt_voltage_v *= 0.0000025f;
    this->shunt_voltage_sensor_->publish_state(shunt_voltage_v);
  }
 
  if (this->current_sensor_ != nullptr) {
    uint16_t raw_current;
    if (!this->read_byte_16(INA226_REGISTER_CURRENT, &raw_current)) {
      this->status_set_warning();
      return;
    }
    // Convert for 2's compliment and signed value
    float current_ma = this->twos_complement_(raw_current, 16);
    current_ma *= (this->calibration_lsb_ / 1000.0f);
    this->current_sensor_->publish_state(current_ma / 1000.0f);
  }
 
  if (this->power_sensor_ != nullptr) {
    uint16_t raw_power;
    if (!this->read_byte_16(INA226_REGISTER_POWER, &raw_power)) {
      this->status_set_warning();
      return;
    }
    float power_mw = int16_t(raw_power) * (this->calibration_lsb_ * 25.0f / 1000.0f);
    this->power_sensor_->publish_state(power_mw / 1000.0f);
  }
 
  this->status_clear_warning();
}
 
int32_t INA226Component::twos_complement_(int32_t val, uint8_t bits) {
  if (val & ((uint32_t) 1 << (bits - 1))) {
    val -= (uint32_t) 1 << bits;
  }
  return val;
}
 
}  // namespace esphome::ina226