130 lines
4.0 KiB
C++
130 lines
4.0 KiB
C++
#include "sht4x.h"
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#include "esphome/core/hal.h"
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#include "esphome/core/log.h"
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namespace esphome::sht4x {
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static const char *const TAG = "sht4x";
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static const uint8_t MEASURECOMMANDS[] = {0xFD, 0xF6, 0xE0};
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static const uint8_t SERIAL_NUMBER_COMMAND = 0x89;
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// Conversion constants from SHT4x datasheet
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static constexpr float TEMPERATURE_OFFSET = -45.0f;
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static constexpr float TEMPERATURE_SPAN = 175.0f;
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static constexpr float HUMIDITY_OFFSET = -6.0f;
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static constexpr float HUMIDITY_SPAN = 125.0f;
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static constexpr float RAW_MAX = 65535.0f;
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void SHT4XComponent::read_serial_number_() {
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uint16_t buffer[2];
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if (!this->get_8bit_register(SERIAL_NUMBER_COMMAND, buffer, 2, 1)) {
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ESP_LOGE(TAG, "Get serial number failed");
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this->serial_number_ = 0;
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return;
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}
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this->serial_number_ = (uint32_t(buffer[0]) << 16) | (uint32_t(buffer[1]));
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ESP_LOGD(TAG, "Serial number: %08" PRIx32, this->serial_number_);
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}
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void SHT4XComponent::setup() {
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auto err = this->write(nullptr, 0);
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if (err != i2c::ERROR_OK) {
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this->mark_failed();
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return;
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}
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this->read_serial_number_();
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if (std::isfinite(this->duty_cycle_) && this->duty_cycle_ > 0.0f) {
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this->heater_interval_ = static_cast<uint32_t>(static_cast<uint16_t>(this->heater_time_) / this->duty_cycle_);
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ESP_LOGD(TAG, "Heater interval: %" PRIu32, this->heater_interval_);
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if (this->heater_power_ == SHT4X_HEATERPOWER_HIGH) {
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if (this->heater_time_ == SHT4X_HEATERTIME_LONG) {
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this->heater_command_ = 0x39;
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} else {
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this->heater_command_ = 0x32;
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}
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} else if (this->heater_power_ == SHT4X_HEATERPOWER_MED) {
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if (this->heater_time_ == SHT4X_HEATERTIME_LONG) {
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this->heater_command_ = 0x2F;
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} else {
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this->heater_command_ = 0x24;
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}
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} else {
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if (this->heater_time_ == SHT4X_HEATERTIME_LONG) {
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this->heater_command_ = 0x1E;
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} else {
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this->heater_command_ = 0x15;
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}
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}
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ESP_LOGD(TAG, "Heater command: %x", this->heater_command_);
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}
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}
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void SHT4XComponent::dump_config() {
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ESP_LOGCONFIG(TAG,
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"SHT4x:\n"
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" Serial number: %08" PRIx32,
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this->serial_number_);
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LOG_I2C_DEVICE(this);
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if (this->is_failed()) {
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ESP_LOGE(TAG, ESP_LOG_MSG_COMM_FAIL);
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}
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if (this->serial_number_ == 0) {
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ESP_LOGW(TAG, "Get serial number failed");
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}
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}
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void SHT4XComponent::update() {
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// Send command
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if (!this->write_command(MEASURECOMMANDS[this->precision_])) {
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// Warning will be printed only if warning status is not set yet
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this->status_set_warning(LOG_STR("Failed to send measurement command"));
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return;
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}
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this->set_timeout(10, [this]() {
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uint16_t buffer[2];
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// Read measurement
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if (!this->read_data(buffer, 2)) {
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// Using ESP_LOGW to force the warning to be printed
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ESP_LOGW(TAG, "Sensor read failed");
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this->status_set_warning();
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return;
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}
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this->status_clear_warning();
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// Evaluate and publish measurements
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if (this->temp_sensor_ != nullptr) {
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// Temp is contained in the first result word
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float temp = TEMPERATURE_OFFSET + TEMPERATURE_SPAN * static_cast<float>(buffer[0]) / RAW_MAX;
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this->temp_sensor_->publish_state(temp);
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}
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if (this->humidity_sensor_ != nullptr) {
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// Relative humidity is in the second result word
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float rh = HUMIDITY_OFFSET + HUMIDITY_SPAN * static_cast<float>(buffer[1]) / RAW_MAX;
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this->humidity_sensor_->publish_state(rh);
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}
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// Fire heater after measurement to maximize cooldown time before the next reading.
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// The heater command produces a measurement that we don't need (datasheet 4.9).
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if (this->heater_interval_ > 0) {
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uint32_t now = millis();
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if (now - this->last_heater_millis_ >= this->heater_interval_) {
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ESP_LOGD(TAG, "Heater turning on");
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if (this->write_command(this->heater_command_)) {
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this->last_heater_millis_ = now;
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}
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}
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}
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});
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}
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} // namespace esphome::sht4x
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