gcja5.cpp

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/* From snooping with a logic analyzer, the I2C on this sensor is broken. I was only able
 * to receive 1's as a response from the sensor. I was able to get the UART working.
 *
 * The datasheet says the values should be divided by 1000, but this must only be for the I2C
 * implementation. Comparing UART values with another sensor, there is no need to divide by 1000.
 */
#include "gcja5.h"
#include "esphome/core/log.h"
#include "esphome/core/application.h"
#include <cstring>
 
namespace esphome::gcja5 {
 
static const char *const TAG = "gcja5";
 
void GCJA5Component::loop() {
  const uint32_t now = App.get_loop_component_start_time();
  if (now - this->last_transmission_ >= 500) {
    // last transmission too long ago. Reset RX index.
    this->rx_message_.clear();
  }
 
  if (this->available() == 0) {
    return;
  }
 
  // There must now be data waiting
  this->last_transmission_ = now;
  uint8_t val;
  while (this->available() != 0) {
    this->read_byte(&val);
    this->rx_message_.push_back(val);
 
    // check if rx_message_ has 32 bytes of data
    if (this->rx_message_.size() == 32) {
      this->parse_data_();
 
      if (this->have_good_data_) {
        if (this->pm_1_0_sensor_ != nullptr)
          this->pm_1_0_sensor_->publish_state(get_32_bit_uint_(1));
        if (this->pm_2_5_sensor_ != nullptr)
          this->pm_2_5_sensor_->publish_state(get_32_bit_uint_(5));
        if (this->pm_10_0_sensor_ != nullptr)
          this->pm_10_0_sensor_->publish_state(get_32_bit_uint_(9));
        if (this->pmc_0_3_sensor_ != nullptr)
          this->pmc_0_3_sensor_->publish_state(get_16_bit_uint_(13));
        if (this->pmc_0_5_sensor_ != nullptr)
          this->pmc_0_5_sensor_->publish_state(get_16_bit_uint_(15));
        if (this->pmc_1_0_sensor_ != nullptr)
          this->pmc_1_0_sensor_->publish_state(get_16_bit_uint_(17));
        if (this->pmc_2_5_sensor_ != nullptr)
          this->pmc_2_5_sensor_->publish_state(get_16_bit_uint_(21));
        if (this->pmc_5_0_sensor_ != nullptr)
          this->pmc_5_0_sensor_->publish_state(get_16_bit_uint_(23));
        if (this->pmc_10_0_sensor_ != nullptr)
          this->pmc_10_0_sensor_->publish_state(get_16_bit_uint_(25));
      } else {
        this->status_set_warning();
        ESP_LOGV(TAG, "Have 32 bytes but not good data. Skipping.");
      }
 
      this->rx_message_.clear();
    }
  }
}
 
bool GCJA5Component::calculate_checksum_() {
  uint8_t crc = 0;
 
  for (uint8_t i = 1; i < 30; i++)
    crc = crc ^ this->rx_message_[i];
 
  ESP_LOGVV(TAG, "Checksum packet was (0x%02X), calculated checksum was (0x%02X)", this->rx_message_[30], crc);
 
  return (crc == this->rx_message_[30]);
}
 
void GCJA5Component::parse_data_() {
  ESP_LOGVV(TAG, "GCJA5 Data: ");
  for (uint8_t i = 0; i < 32; i++) {
    ESP_LOGVV(TAG, "  %u: 0b" BYTE_TO_BINARY_PATTERN " (0x%02X)", i + 1, BYTE_TO_BINARY(this->rx_message_[i]),
              this->rx_message_[i]);
  }
 
  if (this->rx_message_[0] != 0x02 || this->rx_message_[31] != 0x03 || !this->calculate_checksum_()) {
    ESP_LOGVV(TAG, "Discarding bad packet - failed checks.");
    return;
  } else {
    ESP_LOGVV(TAG, "Good packet found.");
  }
 
  this->have_good_data_ = true;
  uint8_t status = this->rx_message_[29];
  if (!this->first_status_log_) {
    this->first_status_log_ = true;
 
    ESP_LOGI(TAG,
             "GCJA5 Status\n"
             "  Overall Status : %i\n"
             "  PD Status      : %i\n"
             "  LD Status      : %i\n"
             "  Fan Status     : %i",
             (status >> 6) & 0x03, (status >> 4) & 0x03, (status >> 2) & 0x03, (status >> 0) & 0x03);
  }
}
 
void GCJA5Component::dump_config() { ; }
 
}  // namespace esphome::gcja5