esphome/esphome/components/sdp3x/sdp3x.cpp

#include "sdp3x.h"
#include "esphome/core/log.h"
#include "esphome/core/hal.h"
#include "esphome/core/helpers.h"

namespace esphome {
namespace sdp3x {

static const char *const TAG = "sdp3x.sensor";
static const uint8_t SDP3X_SOFT_RESET[2] = {0x00, 0x06};
static const uint8_t SDP3X_READ_ID1[2] = {0x36, 0x7C};
static const uint8_t SDP3X_READ_ID2[2] = {0xE1, 0x02};
static const uint8_t SDP3X_START_DP_AVG[2] = {0x36, 0x15};
static const uint8_t SDP3X_START_MASS_FLOW_AVG[2] = {0x36, 0x03};
static const uint8_t SDP3X_STOP_MEAS[2] = {0x3F, 0xF9};

void SDP3XComponent::update() { this->read_pressure_(); }

void SDP3XComponent::setup() {
  ESP_LOGD(TAG, "Setting up SDP3X...");

  if (this->write(SDP3X_STOP_MEAS, 2) != i2c::ERROR_OK) {
    ESP_LOGW(TAG, "Stop SDP3X failed!");  // This sometimes fails for no good reason
  }

  if (this->write(SDP3X_SOFT_RESET, 2) != i2c::ERROR_OK) {
    ESP_LOGW(TAG, "Soft Reset SDP3X failed!");  // This sometimes fails for no good reason
  }

  this->set_timeout(20, [this] {
    if (this->write(SDP3X_READ_ID1, 2) != i2c::ERROR_OK) {
      ESP_LOGE(TAG, "Read ID1 SDP3X failed!");
      this->mark_failed();
      return;
    }
    if (this->write(SDP3X_READ_ID2, 2) != i2c::ERROR_OK) {
      ESP_LOGE(TAG, "Read ID2 SDP3X failed!");
      this->mark_failed();
      return;
    }

    uint8_t data[18];
    if (this->read(data, 18) != i2c::ERROR_OK) {
      ESP_LOGE(TAG, "Read ID SDP3X failed!");
      this->mark_failed();
      return;
    }
    if (!(check_crc_(&data[0], 2, data[2]) && check_crc_(&data[3], 2, data[5]))) {
      ESP_LOGE(TAG, "CRC ID SDP3X failed!");
      this->mark_failed();
      return;
    }

    // SDP8xx
    // ref:
    // https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/8_Differential_Pressure/Datasheets/Sensirion_Differential_Pressure_Datasheet_SDP8xx_Digital.pdf
    if (data[2] == 0x02) {
      switch (data[3]) {
        case 0x01:  // SDP800-500Pa
          ESP_LOGCONFIG(TAG, "Sensor is SDP800-500Pa");
          break;
        case 0x0A:  // SDP810-500Pa
          ESP_LOGCONFIG(TAG, "Sensor is SDP810-500Pa");
          break;
        case 0x04:  // SDP801-500Pa
          ESP_LOGCONFIG(TAG, "Sensor is SDP801-500Pa");
          break;
        case 0x0D:  // SDP811-500Pa
          ESP_LOGCONFIG(TAG, "Sensor is SDP811-500Pa");
          break;
        case 0x02:  // SDP800-125Pa
          ESP_LOGCONFIG(TAG, "Sensor is SDP800-125Pa");
          break;
        case 0x0B:  // SDP810-125Pa
          ESP_LOGCONFIG(TAG, "Sensor is SDP810-125Pa");
          break;
      }
    } else if (data[2] == 0x01) {
      if (data[3] == 0x01) {
        ESP_LOGCONFIG(TAG, "Sensor is SDP31-500Pa");
      } else if (data[3] == 0x02) {
        ESP_LOGCONFIG(TAG, "Sensor is SDP32-125Pa");
      }
    }

    if (this->write(measurement_mode_ == DP_AVG ? SDP3X_START_DP_AVG : SDP3X_START_MASS_FLOW_AVG, 2) != i2c::ERROR_OK) {
      ESP_LOGE(TAG, "Start Measurements SDP3X failed!");
      this->mark_failed();
      return;
    }
    ESP_LOGCONFIG(TAG, "SDP3X started!");
  });
}
void SDP3XComponent::dump_config() {
  LOG_SENSOR("  ", "SDP3X", this);
  LOG_I2C_DEVICE(this);
  if (this->is_failed()) {
    ESP_LOGE(TAG, "  Connection with SDP3X failed!");
  }
  LOG_UPDATE_INTERVAL(this);
}

void SDP3XComponent::read_pressure_() {
  uint8_t data[9];
  if (this->read(data, 9) != i2c::ERROR_OK) {
    ESP_LOGW(TAG, "Couldn't read SDP3X data!");
    this->status_set_warning();
    return;
  }

  if (!(check_crc_(&data[0], 2, data[2]) && check_crc_(&data[3], 2, data[5]) && check_crc_(&data[6], 2, data[8]))) {
    ESP_LOGW(TAG, "Invalid SDP3X data!");
    this->status_set_warning();
    return;
  }

  int16_t pressure_raw = encode_uint16(data[0], data[1]);
  int16_t temperature_raw = encode_uint16(data[3], data[4]);
  int16_t scale_factor_raw = encode_uint16(data[6], data[7]);
  // scale factor is in Pa - convert to hPa
  float pressure = pressure_raw / (scale_factor_raw * 100.0f);
  ESP_LOGV(TAG, "Got raw pressure=%d, raw scale factor =%d, raw temperature=%d ", pressure_raw, scale_factor_raw,
           temperature_raw);
  ESP_LOGD(TAG, "Got Pressure=%.3f hPa", pressure);

  this->publish_state(pressure);
  this->status_clear_warning();
}

float SDP3XComponent::get_setup_priority() const { return setup_priority::DATA; }

// Check CRC function from SDP3X sample code provided by sensirion
// Returns true if a checksum is OK
bool SDP3XComponent::check_crc_(const uint8_t data[], uint8_t size, uint8_t checksum) {
  uint8_t crc = 0xFF;

  // calculates 8-Bit checksum with given polynomial 0x31 (x^8 + x^5 + x^4 + 1)
  for (int i = 0; i < size; i++) {
    crc ^= (data[i]);
    for (uint8_t bit = 8; bit > 0; --bit) {
      if (crc & 0x80) {
        crc = (crc << 1) ^ 0x31;
      } else {
        crc = (crc << 1);
      }
    }
  }

  // verify checksum
  return (crc == checksum);
}

}  // namespace sdp3x
}  // namespace esphome