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726b0e73d9
* Add more efficient SPI implementation * Lint * Add 200KHZ * Updates * Fix write_byte * Update from datasheet * Shift clock * Fix calculation
87 lines
2.5 KiB
C++
87 lines
2.5 KiB
C++
#include "max31855.h"
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#include "esphome/core/log.h"
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namespace esphome {
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namespace max31855 {
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static const char *TAG = "max31855";
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void MAX31855Sensor::update() {
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this->enable();
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delay(1);
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// conversion initiated by rising edge
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this->disable();
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// Conversion time typ: 170ms, max: 220ms
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auto f = std::bind(&MAX31855Sensor::read_data_, this);
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this->set_timeout("value", 220, f);
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}
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void MAX31855Sensor::setup() {
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ESP_LOGCONFIG(TAG, "Setting up MAX31855Sensor '%s'...", this->name_.c_str());
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this->spi_setup();
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}
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void MAX31855Sensor::dump_config() {
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LOG_SENSOR("", "MAX31855", this);
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LOG_PIN(" CS Pin: ", this->cs_);
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LOG_UPDATE_INTERVAL(this);
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}
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float MAX31855Sensor::get_setup_priority() const { return setup_priority::DATA; }
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void MAX31855Sensor::read_data_() {
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this->enable();
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delay(1);
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uint8_t data[4];
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this->read_array(data, 4);
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// val is 14 bits of signed temperature data followed by 2 bits of status flags
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int16_t val = data[1] | data[0] << 8;
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// test data from MAX31855 datasheet
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// val = 0x6400 // 1600.00°C
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// val = 0x3E80 // 1000.00°C
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// val = 0x064C // 100.75°C
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// val = 0x0190 // 25.00°C
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// val = 0x0000 // 0.00°C
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// val = 0xFFFC // -0.25°C
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// val = 0xFFF0 // -1.00°C
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// val = 0xF060 // -250.00°C
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this->disable();
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if ((data[3] & 0x01) != 0) {
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ESP_LOGW(TAG, "Got thermocouple not connected from MAX31855Sensor (0x%04X) (0x%04X)", val, data[3] | data[2] << 8);
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this->status_set_warning();
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return;
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}
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if ((data[3] & 0x02) != 0) {
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ESP_LOGW(TAG, "Got short circuit to ground from MAX31855Sensor (0x%04X) (0x%04X)", val, data[3] | data[2] << 8);
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this->status_set_warning();
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return;
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}
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if ((data[3] & 0x04) != 0) {
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ESP_LOGW(TAG, "Got short circuit to power from MAX31855Sensor (0x%04X) (0x%04X)", val, data[3] | data[2] << 8);
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this->status_set_warning();
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return;
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}
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if ((data[1] & 0x01) != 0) {
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ESP_LOGW(TAG, "Got faulty reading from MAX31855Sensor (0x%04X) (0x%04X)", val, data[3] | data[2] << 8);
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this->status_set_warning();
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return;
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}
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if ((val & 0x8000) != 0) {
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// Negative value, drop the lower 2 bits and explicitly extend sign bits.
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val = 0xE000 | ((val >> 2) & 0x1FFF);
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} else {
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// Positive value, just drop the lower 2 bits.
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val >>= 2;
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}
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float temperature = float(val) / 4.0f;
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ESP_LOGD(TAG, "'%s': Got temperature=%.1f°C", this->name_.c_str(), temperature);
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this->publish_state(temperature);
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this->status_clear_warning();
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}
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} // namespace max31855
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} // namespace esphome
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