esphome/esphome/components/max31855/max31855.cpp

108 lines
3 KiB
C++

#include "max31855.h"
#include "esphome/core/log.h"
namespace esphome {
namespace max31855 {
static const char *const TAG = "max31855";
void MAX31855Sensor::update() {
this->enable();
delay(1);
// conversion initiated by rising edge
this->disable();
// Conversion time typ: 170ms, max: 220ms
auto f = std::bind(&MAX31855Sensor::read_data_, this);
this->set_timeout("value", 220, f);
}
void MAX31855Sensor::setup() {
ESP_LOGCONFIG(TAG, "Setting up MAX31855Sensor '%s'...", this->name_.c_str());
this->spi_setup();
}
void MAX31855Sensor::dump_config() {
ESP_LOGCONFIG(TAG, "MAX31855:");
LOG_PIN(" CS Pin: ", this->cs_);
LOG_UPDATE_INTERVAL(this);
LOG_SENSOR(" ", "Thermocouple", this);
if (this->temperature_reference_) {
LOG_SENSOR(" ", "Reference", this->temperature_reference_);
} else {
ESP_LOGCONFIG(TAG, " Reference temperature disabled.");
}
}
float MAX31855Sensor::get_setup_priority() const { return setup_priority::DATA; }
void MAX31855Sensor::read_data_() {
this->enable();
delay(1);
uint8_t data[4];
this->read_array(data, 4);
this->disable();
const uint32_t mem = encode_uint32(data[0], data[1], data[2], data[3]);
// Verify we got data
if (mem != 0xFFFFFFFF) {
this->status_clear_error();
} else {
ESP_LOGE(TAG, "No data received from MAX31855 (0x%08X). Check wiring!", mem);
this->publish_state(NAN);
if (this->temperature_reference_) {
this->temperature_reference_->publish_state(NAN);
}
this->status_set_error();
return;
}
// Internal reference temperature always works
if (this->temperature_reference_) {
int16_t val = (mem & 0x0000FFF0) >> 4;
if (val & 0x0800) {
val |= 0xF000; // Pad out 2's complement
}
const float t_ref = float(val) * 0.0625f;
ESP_LOGD(TAG, "Got reference temperature: %.4f°C", t_ref);
this->temperature_reference_->publish_state(t_ref);
}
// Check thermocouple faults
if (mem & 0x00000001) {
ESP_LOGW(TAG, "Thermocouple open circuit (not connected) fault from MAX31855 (0x%08X)", mem);
this->publish_state(NAN);
this->status_set_warning();
return;
}
if (mem & 0x00000002) {
ESP_LOGW(TAG, "Thermocouple short circuit to ground fault from MAX31855 (0x%08X)", mem);
this->publish_state(NAN);
this->status_set_warning();
return;
}
if (mem & 0x00000004) {
ESP_LOGW(TAG, "Thermocouple short circuit to VCC fault from MAX31855 (0x%08X)", mem);
this->publish_state(NAN);
this->status_set_warning();
return;
}
if (mem & 0x00010000) {
ESP_LOGW(TAG, "Got faulty reading from MAX31855 (0x%08X)", mem);
this->publish_state(NAN);
this->status_set_warning();
return;
}
// Decode thermocouple temperature
int16_t val = (mem & 0xFFFC0000) >> 18;
if (val & 0x2000) {
val |= 0xC000; // Pad out 2's complement
}
const float t_sense = float(val) * 0.25f;
ESP_LOGD(TAG, "Got thermocouple temperature: %.2f°C", t_sense);
this->publish_state(t_sense);
this->status_clear_warning();
}
} // namespace max31855
} // namespace esphome