esphome/esphome/components/ccs811/ccs811.cpp

#include "ccs811.h"
#include "esphome/core/log.h"

namespace esphome {
namespace ccs811 {

static const char *TAG = "ccs811";

// based on
//  - https://cdn.sparkfun.com/datasheets/BreakoutBoards/CCS811_Programming_Guide.pdf

#define CHECK_TRUE(f, error_code) \
  if (!(f)) { \
    this->mark_failed(); \
    this->error_code_ = (error_code); \
    return; \
  }

#define CHECKED_IO(f) CHECK_TRUE(f, COMMUNICAITON_FAILED)

void CCS811Component::setup() {
  // page 9 programming guide - hwid is always 0x81
  uint8_t hw_id;
  CHECKED_IO(this->read_byte(0x20, &hw_id))
  CHECK_TRUE(hw_id == 0x81, INVALID_ID)

  // software reset, page 3 - allowed to fail
  this->write_bytes(0xFF, {0x11, 0xE5, 0x72, 0x8A});
  delay(5);

  // page 10, APP_START
  CHECK_TRUE(!this->status_has_error_(), SENSOR_REPORTED_ERROR)
  CHECK_TRUE(this->status_app_is_valid_(), APP_INVALID)
  CHECK_TRUE(this->write_bytes(0xF4, {}), APP_START_FAILED)
  // App setup, wait for it to load
  delay(1);

  // set MEAS_MODE (page 5)
  uint8_t meas_mode = 0;
  uint32_t interval = this->get_update_interval();
  if (interval <= 1000)
    meas_mode = 1 << 4;
  else if (interval <= 10000)
    meas_mode = 2 << 4;
  else
    meas_mode = 3 << 4;

  CHECKED_IO(this->write_byte(0x01, meas_mode))

  if (this->baseline_.has_value()) {
    // baseline available, write to sensor
    this->write_bytes(0x11, decode_uint16(*this->baseline_));
  }
}
void CCS811Component::update() {
  if (!this->status_has_data_())
    this->status_set_warning();

  // page 12 - alg result data
  auto alg_data = this->read_bytes<4>(0x02);
  if (!alg_data.has_value()) {
    ESP_LOGW(TAG, "Reading CCS811 data failed!");
    this->status_set_warning();
    return;
  }
  auto res = *alg_data;
  uint16_t co2 = encode_uint16(res[0], res[1]);
  uint16_t tvoc = encode_uint16(res[2], res[3]);

  // also print baseline
  auto baseline_data = this->read_bytes<2>(0x11);
  uint16_t baseline = 0;
  if (baseline_data.has_value()) {
    baseline = encode_uint16((*baseline_data)[0], (*baseline_data)[1]);
  }

  ESP_LOGD(TAG, "Got co2=%u ppm, tvoc=%u ppb, baseline=0x%04X", co2, tvoc, baseline);

  if (this->co2_ != nullptr)
    this->co2_->publish_state(co2);
  if (this->tvoc_ != nullptr)
    this->tvoc_->publish_state(tvoc);

  this->status_clear_warning();

  this->send_env_data_();
}
void CCS811Component::send_env_data_() {
  if (this->humidity_ == nullptr && this->temperature_ == nullptr)
    return;

  float humidity = NAN;
  if (this->humidity_ != nullptr)
    humidity = this->humidity_->state;
  if (isnan(humidity) || humidity < 0 || humidity > 100)
    humidity = 50;
  float temperature = NAN;
  if (this->temperature_ != nullptr)
    temperature = this->temperature_->state;
  if (isnan(temperature) || temperature < -25 || temperature > 50)
    temperature = 25;
  // temperature has a 25° offset to allow negative temperatures
  temperature += 25;

  // only 0.5 fractions are supported (application note)
  auto hum_value = static_cast<uint8_t>(roundf(humidity * 2));
  auto temp_value = static_cast<uint8_t>(roundf(temperature * 2));
  this->write_bytes(0x05, {hum_value, 0x00, temp_value, 0x00});
}
void CCS811Component::dump_config() {
  ESP_LOGCONFIG(TAG, "CCS811");
  LOG_I2C_DEVICE(this)
  LOG_UPDATE_INTERVAL(this)
  LOG_SENSOR("  ", "CO2 Sensor", this->co2_)
  LOG_SENSOR("  ", "TVOC Sensor", this->tvoc_)
  if (this->baseline_) {
    ESP_LOGCONFIG(TAG, "  Baseline: %04X", *this->baseline_);
  } else {
    ESP_LOGCONFIG(TAG, "  Baseline: NOT SET");
  }
  if (this->is_failed()) {
    switch (this->error_code_) {
      case COMMUNICAITON_FAILED:
        ESP_LOGW(TAG, "Communication failed! Is the sensor connected?");
        break;
      case INVALID_ID:
        ESP_LOGW(TAG, "Sensor reported an invalid ID. Is this a CCS811?");
        break;
      case SENSOR_REPORTED_ERROR:
        ESP_LOGW(TAG, "Sensor reported internal error");
        break;
      case APP_INVALID:
        ESP_LOGW(TAG, "Sensor reported invalid APP installed.");
        break;
      case APP_START_FAILED:
        ESP_LOGW(TAG, "Sensor reported APP start failed.");
        break;
      case UNKNOWN:
      default:
        ESP_LOGW(TAG, "Unknown setup error!");
        break;
    }
  }
}

}  // namespace ccs811
}  // namespace esphome