Implement all supported thermocouple types for MAX31856 (#7218)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Co-authored-by: Clyde Stubbs <2366188+clydebarrow@users.noreply.github.com>

esphome/components/max31856/max31856.cpp

@@ -32,6 +32,12 @@ void MAX31856Sensor::dump_config() {
   LOG_PIN("  CS Pin: ", this->cs_);
   ESP_LOGCONFIG(TAG, "  Mains Filter: %s",
                 (filter_ == FILTER_60HZ ? "60 Hz" : (filter_ == FILTER_50HZ ? "50 Hz" : "Unknown!")));
+  if (this->thermocouple_type_ < 0 || this->thermocouple_type_ > 7) {
+    ESP_LOGCONFIG(TAG, "  Thermocouple Type: Unknown");
+  } else {
+    ESP_LOGCONFIG(TAG, "  Thermocouple Type: %c", "BEJKNRST"[this->thermocouple_type_]);
+  }
+
   LOG_UPDATE_INTERVAL(this);
 }
 
@@ -129,7 +135,12 @@ void MAX31856Sensor::clear_fault_() {
 }
 
 void MAX31856Sensor::set_thermocouple_type_() {
-  MAX31856ThermocoupleType type = MAX31856_TCTYPE_K;
+  MAX31856ThermocoupleType type;
+  if (this->thermocouple_type_ < 0 || this->thermocouple_type_ > 7) {
+    type = MAX31856_TCTYPE_K;
+  } else {
+    type = this->thermocouple_type_;
+  }
   ESP_LOGCONFIG(TAG, "set_thermocouple_type_: 0x%02X", type);
   uint8_t t = this->read_register_(MAX31856_CR1_REG);
   t &= 0xF0;  // mask off bottom 4 bits

esphome/components/max31856/max31856.h

@@ -50,7 +50,6 @@ enum MAX31856Registers {
 
 /**
  * Multiple types of thermocouples supported by the chip.
- * Currently only K type implemented here.
  */
 enum MAX31856ThermocoupleType {
   MAX31856_TCTYPE_B = 0b0000,   // 0x00
@@ -78,11 +77,15 @@ class MAX31856Sensor : public sensor::Sensor,
   void setup() override;
   void dump_config() override;
   float get_setup_priority() const override;
-  void set_filter(MAX31856ConfigFilter filter) { filter_ = filter; }
+  void set_filter(MAX31856ConfigFilter filter) { this->filter_ = filter; }
+  void set_thermocouple_type(MAX31856ThermocoupleType thermocouple_type) {
+    this->thermocouple_type_ = thermocouple_type;
+  }
   void update() override;
 
  protected:
   MAX31856ConfigFilter filter_;
+  MAX31856ThermocoupleType thermocouple_type_;
 
   uint8_t read_register_(uint8_t reg);
   uint32_t read_register24_(uint8_t reg);

esphome/components/max31856/sensor.py

@@ -3,6 +3,7 @@ from esphome.components import sensor, spi
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_MAINS_FILTER,
+    CONF_THERMOCOUPLE_TYPE,
     DEVICE_CLASS_TEMPERATURE,
     STATE_CLASS_MEASUREMENT,
     UNIT_CELSIUS,
@@ -18,6 +19,17 @@ FILTER = {
     50: MAX31865ConfigFilter.FILTER_50HZ,
     60: MAX31865ConfigFilter.FILTER_60HZ,
 }
+MAX31856ThermocoupleType = max31856_ns.enum("MAX31856ThermocoupleType")
+THERMOCOUPLE_TYPE = {
+    "B": MAX31856ThermocoupleType.MAX31856_TCTYPE_B,
+    "E": MAX31856ThermocoupleType.MAX31856_TCTYPE_E,
+    "J": MAX31856ThermocoupleType.MAX31856_TCTYPE_J,
+    "K": MAX31856ThermocoupleType.MAX31856_TCTYPE_K,
+    "N": MAX31856ThermocoupleType.MAX31856_TCTYPE_N,
+    "R": MAX31856ThermocoupleType.MAX31856_TCTYPE_R,
+    "S": MAX31856ThermocoupleType.MAX31856_TCTYPE_S,
+    "T": MAX31856ThermocoupleType.MAX31856_TCTYPE_T,
+}
 
 CONFIG_SCHEMA = (
     sensor.sensor_schema(
@@ -34,6 +46,13 @@ CONFIG_SCHEMA = (
             ),
         }
     )
+    .extend(
+        {
+            cv.Optional(CONF_THERMOCOUPLE_TYPE, default="K"): cv.enum(
+                THERMOCOUPLE_TYPE, upper=True, space=""
+            ),
+        }
+    )
     .extend(cv.polling_component_schema("60s"))
     .extend(spi.spi_device_schema())
 )
@@ -44,3 +63,4 @@ async def to_code(config):
     await cg.register_component(var, config)
     await spi.register_spi_device(var, config)
     cg.add(var.set_filter(config[CONF_MAINS_FILTER]))
+    cg.add(var.set_thermocouple_type(config[CONF_THERMOCOUPLE_TYPE]))

esphome/components/mcp9600/sensor.py

@@ -1,14 +1,14 @@
 import esphome.codegen as cg
-import esphome.config_validation as cv
 from esphome.components import i2c, sensor
+import esphome.config_validation as cv
 from esphome.const import (
     CONF_ID,
+    CONF_THERMOCOUPLE_TYPE,
     DEVICE_CLASS_TEMPERATURE,
     STATE_CLASS_MEASUREMENT,
     UNIT_CELSIUS,
 )
 
-CONF_THERMOCOUPLE_TYPE = "thermocouple_type"
 CONF_HOT_JUNCTION = "hot_junction"
 CONF_COLD_JUNCTION = "cold_junction"
 

esphome/const.py

@@ -852,6 +852,7 @@ CONF_TEMPERATURE_STEP = "temperature_step"
 CONF_TEXT = "text"
 CONF_TEXT_SENSORS = "text_sensors"
 CONF_THEN = "then"
+CONF_THERMOCOUPLE_TYPE = "thermocouple_type"
 CONF_THRESHOLD = "threshold"
 CONF_THROTTLE = "throttle"
 CONF_TILT = "tilt"

tests/components/max31856/test.esp32-ard.yaml

@@ -10,3 +10,4 @@ sensor:
     cs_pin: 12
     update_interval: 15s
     mains_filter: 50Hz
+    thermocouple_type: N

tests/components/max31856/test.esp32-c3-ard.yaml

@@ -10,3 +10,5 @@ sensor:
     cs_pin: 8
     update_interval: 15s
     mains_filter: 50Hz
+    thermocouple_type: N
+

tests/components/max31856/test.esp32-c3-idf.yaml

@@ -10,3 +10,5 @@ sensor:
     cs_pin: 8
     update_interval: 15s
     mains_filter: 50Hz
+    thermocouple_type: N
+

tests/components/max31856/test.esp32-idf.yaml

@@ -10,3 +10,4 @@ sensor:
     cs_pin: 12
     update_interval: 15s
     mains_filter: 50Hz
+    thermocouple_type: N

tests/components/max31856/test.esp8266-ard.yaml

@@ -10,3 +10,5 @@ sensor:
     cs_pin: 15
     update_interval: 15s
     mains_filter: 50Hz
+    thermocouple_type: N
+

tests/components/max31856/test.rp2040-ard.yaml

@@ -10,3 +10,5 @@ sensor:
     cs_pin: 6
     update_interval: 15s
     mains_filter: 50Hz
+    thermocouple_type: N
+