tc74.cpp

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// Based on the TC74 datasheet https://ww1.microchip.com/downloads/en/DeviceDoc/21462D.pdf
 
#include "tc74.h"
#include "esphome/core/log.h"
 
namespace esphome::tc74 {
 
ESPHOME_LOG_TAG(TAG, "tc74");
 
static const uint8_t TC74_REGISTER_TEMPERATURE = 0x00;
static const uint8_t TC74_REGISTER_CONFIGURATION = 0x01;
static const uint8_t TC74_DATA_READY_MASK = 0x40;
 
// It is possible the "Data Ready" bit will not be set if the TC74 has not been powered on for at least 250ms, so it not
// being set does not constitute a failure.
void TC74Component::setup() {
  uint8_t config_reg;
  if (this->read_register(TC74_REGISTER_CONFIGURATION, &config_reg, 1) != i2c::ERROR_OK) {
    this->mark_failed(LOG_STR(ESP_LOG_MSG_COMM_FAIL));
    return;
  }
  this->data_ready_ = config_reg & TC74_DATA_READY_MASK;
}
 
void TC74Component::update() { this->read_temperature_(); }
 
void TC74Component::dump_config() {
  LOG_SENSOR("", "TC74", this);
  LOG_I2C_DEVICE(this);
  LOG_UPDATE_INTERVAL(this);
}
 
void TC74Component::read_temperature_() {
  if (!this->data_ready_) {
    uint8_t config_reg;
    if (this->read_register(TC74_REGISTER_CONFIGURATION, &config_reg, 1) != i2c::ERROR_OK) {
      this->status_set_warning();
      return;
    }
 
    if (config_reg & TC74_DATA_READY_MASK) {
      this->data_ready_ = true;
    } else {
      ESP_LOGD(TAG, "TC74 not ready");
      return;
    }
  }
 
  int8_t temperature_reg;
  if (this->read_register(TC74_REGISTER_TEMPERATURE, reinterpret_cast<uint8_t *>(&temperature_reg), 1) !=
      i2c::ERROR_OK) {
    this->status_set_warning();
    return;
  }
 
  ESP_LOGD(TAG, "Got Temperature=%d °C", temperature_reg);
  this->publish_state(temperature_reg);
  this->status_clear_warning();
}
 
}  // namespace esphome::tc74