Chamber temperature monitoring and auto fan control.

This is an initial cut for feedback, updated for 2.0.x.

Chamber temperature is currently reported along with hot end and bed
temperatures to serial. The format is just like that used for hot end
and bed temperatures, but using 'C' prefix. As there is no heater,
target is always 0. Is this appropriate, is there a better way to report
chamber temperatures?

Chamber temperatures are not reported on the LCD in any way.

When auto chamber fan is enabled, it currently just uses the same
temperature threshold as the other auto controlled fans.

As the chamber temperature is not connected to any heater, it doesn't
undergo mintemp/maxtemp monitoring. This would need to change in the
future if chamber heating became a feature.

Marlin/Configuration.h

 #define TEMP_SENSOR_3 0
 #define TEMP_SENSOR_4 0
 #define TEMP_SENSOR_BED 0
+#define TEMP_SENSOR_CHAMBER 0
 
 // Dummy thermistor constant temperature readings, for use with 998 and 999
 #define DUMMY_THERMISTOR_998_VALUE 25

Marlin/Configuration_adv.h

 #define E2_AUTO_FAN_PIN -1
 #define E3_AUTO_FAN_PIN -1
 #define E4_AUTO_FAN_PIN -1
+#define CHAMBER_AUTO_FAN_PIN -1
 #define EXTRUDER_AUTO_FAN_TEMPERATURE 50
 #define EXTRUDER_AUTO_FAN_SPEED   255  // == full speed
 

Marlin/src/HAL/HAL_AVR/fastio_AVR.h

 
 //find out which harware PWMs are already in use
 #if PIN_EXISTS(CONTROLLER_FAN)
-  #define PWM_CHK_FAN_B(p) (p == CONTROLLER_FAN_PIN || p == E0_AUTO_FAN_PIN || p ==  E1_AUTO_FAN_PIN || p ==  E2_AUTO_FAN_PIN || p ==  E3_AUTO_FAN_PIN || p ==  E4_AUTO_FAN_PIN)
+  #define PWM_CHK_FAN_B(p) (p == CONTROLLER_FAN_PIN || p == E0_AUTO_FAN_PIN || p ==  E1_AUTO_FAN_PIN || p ==  E2_AUTO_FAN_PIN || p ==  E3_AUTO_FAN_PIN || p ==  E4_AUTO_FAN_PIN || p == CHAMBER_AUTO_FAN_PIN)
 #else
-  #define PWM_CHK_FAN_B(p) (p == E0_AUTO_FAN_PIN || p ==  E1_AUTO_FAN_PIN || p ==  E2_AUTO_FAN_PIN || p ==  E3_AUTO_FAN_PIN || p ==  E4_AUTO_FAN_PIN)
+  #define PWM_CHK_FAN_B(p) (p == E0_AUTO_FAN_PIN || p ==  E1_AUTO_FAN_PIN || p ==  E2_AUTO_FAN_PIN || p ==  E3_AUTO_FAN_PIN || p ==  E4_AUTO_FAN_PIN || p == CHAMBER_AUTO_FAN_PIN)
 #endif
 
 #if PIN_EXISTS(FAN) || PIN_EXISTS(FAN1) || PIN_EXISTS(FAN2)

Marlin/src/inc/Conditionals_post.h

   #define BED_USES_THERMISTOR
 #endif
 
+#if TEMP_SENSOR_CHAMBER <= -2
+  #error "MAX6675 / MAX31855 Thermocouples not supported for TEMP_SENSOR_CHAMBER"
+#elif TEMP_SENSOR_CHAMBER == -1
+  #define CHAMBER_USES_AD595
+#elif TEMP_SENSOR_CHAMBER > 0
+  #define THERMISTORCHAMBER TEMP_SENSOR_CHAMBER
+  #define CHAMBER_USES_THERMISTOR
+#endif
+
 #ifdef __SAM3X8E__
   #define HEATER_USES_AD595 (ENABLED(HEATER_0_USES_AD595) || ENABLED(HEATER_1_USES_AD595) || ENABLED(HEATER_2_USES_AD595) || ENABLED(HEATER_3_USES_AD595))
 #endif
 #define HAS_TEMP_4 (PIN_EXISTS(TEMP_4) && TEMP_SENSOR_4 != 0 && TEMP_SENSOR_4 > -2)
 #define HAS_TEMP_HOTEND (HAS_TEMP_0 || ENABLED(HEATER_0_USES_MAX6675))
 #define HAS_TEMP_BED (PIN_EXISTS(TEMP_BED) && TEMP_SENSOR_BED != 0 && TEMP_SENSOR_BED > -2)
-#define HAS_TEMP_SENSOR (HAS_TEMP_HOTEND || HAS_TEMP_BED)
+#define HAS_TEMP_CHAMBER (PIN_EXISTS(TEMP_CHAMBER) && TEMP_SENSOR_CHAMBER != 0 && TEMP_SENSOR_CHAMBER > -2)
+#define HAS_TEMP_SENSOR (HAS_TEMP_HOTEND || HAS_TEMP_BED || HAS_TEMP_CHAMBER)
 
 // Heaters
 #define HAS_HEATER_0 (PIN_EXISTS(HEATER_0))
 #define HAS_AUTO_FAN_2 (HOTENDS > 2 && PIN_EXISTS(E2_AUTO_FAN))
 #define HAS_AUTO_FAN_3 (HOTENDS > 3 && PIN_EXISTS(E3_AUTO_FAN))
 #define HAS_AUTO_FAN_4 (HOTENDS > 4 && PIN_EXISTS(E4_AUTO_FAN))
-#define HAS_AUTO_FAN (HAS_AUTO_FAN_0 || HAS_AUTO_FAN_1 || HAS_AUTO_FAN_2 || HAS_AUTO_FAN_3)
+#define HAS_AUTO_CHAMBER_FAN (PIN_EXISTS(CHAMBER_AUTO_FAN))
+#define HAS_AUTO_FAN (HAS_AUTO_FAN_0 || HAS_AUTO_FAN_1 || HAS_AUTO_FAN_2 || HAS_AUTO_FAN_3 || HAS_AUTO_CHAMBER_FAN)
 #define AUTO_1_IS_0 (E1_AUTO_FAN_PIN == E0_AUTO_FAN_PIN)
 #define AUTO_2_IS_0 (E2_AUTO_FAN_PIN == E0_AUTO_FAN_PIN)
 #define AUTO_2_IS_1 (E2_AUTO_FAN_PIN == E1_AUTO_FAN_PIN)
 #define AUTO_4_IS_1 (E4_AUTO_FAN_PIN == E1_AUTO_FAN_PIN)
 #define AUTO_4_IS_2 (E4_AUTO_FAN_PIN == E2_AUTO_FAN_PIN)
 #define AUTO_4_IS_3 (E4_AUTO_FAN_PIN == E3_AUTO_FAN_PIN)
+#define AUTO_CHAMBER_IS_0 (CHAMBER_AUTO_FAN_PIN == E0_AUTO_FAN_PIN)
+#define AUTO_CHAMBER_IS_1 (CHAMBER_AUTO_FAN_PIN == E1_AUTO_FAN_PIN)
+#define AUTO_CHAMBER_IS_2 (CHAMBER_AUTO_FAN_PIN == E2_AUTO_FAN_PIN)
+#define AUTO_CHAMBER_IS_3 (CHAMBER_AUTO_FAN_PIN == E3_AUTO_FAN_PIN)
+#define AUTO_CHAMBER_IS_4 (CHAMBER_AUTO_FAN_PIN == E4_AUTO_FAN_PIN)
 
 // Other fans
 #define HAS_FAN0 (PIN_EXISTS(FAN))

Marlin/src/module/temperature.cpp

 // public:
 
 float Temperature::current_temperature[HOTENDS] = { 0.0 },
+      Temperature::current_temperature_chamber = 0.0,
       Temperature::current_temperature_bed = 0.0;
 
 int16_t Temperature::current_temperature_raw[HOTENDS] = { 0 },
         Temperature::target_temperature[HOTENDS] = { 0 },
+        Temperature::current_temperature_chamber_raw = 0,
         Temperature::current_temperature_bed_raw = 0;
 
 #if ENABLED(AUTO_POWER_E_FANS)
 #endif
 
 uint16_t Temperature::raw_temp_value[MAX_EXTRUDERS] = { 0 },
+         Temperature::raw_temp_chamber_value = 0,
          Temperature::raw_temp_bed_value = 0;
 
 // Init min and max temp with extreme values to prevent false errors during startup
 #if HAS_AUTO_FAN
 
   void Temperature::checkExtruderAutoFans() {
-    static const pin_t fanPin[] PROGMEM = { E0_AUTO_FAN_PIN, E1_AUTO_FAN_PIN, E2_AUTO_FAN_PIN, E3_AUTO_FAN_PIN, E4_AUTO_FAN_PIN };
+    static const pin_t fanPin[] PROGMEM = { E0_AUTO_FAN_PIN, E1_AUTO_FAN_PIN, E2_AUTO_FAN_PIN, E3_AUTO_FAN_PIN, E4_AUTO_FAN_PIN, CHAMBER_AUTO_FAN_PIN };
     static const uint8_t fanBit[] PROGMEM = {
                     0,
       AUTO_1_IS_0 ? 0 :               1,
       AUTO_2_IS_0 ? 0 : AUTO_2_IS_1 ? 1 :               2,
       AUTO_3_IS_0 ? 0 : AUTO_3_IS_1 ? 1 : AUTO_3_IS_2 ? 2 :               3,
-      AUTO_4_IS_0 ? 0 : AUTO_4_IS_1 ? 1 : AUTO_4_IS_2 ? 2 : AUTO_4_IS_3 ? 3 : 4
+      AUTO_4_IS_0 ? 0 : AUTO_4_IS_1 ? 1 : AUTO_4_IS_2 ? 2 : AUTO_4_IS_3 ? 3 : 4,
+      AUTO_CHAMBER_IS_0 ? 0 : AUTO_CHAMBER_IS_1 ? 1 : AUTO_CHAMBER_IS_2 ? 2 : AUTO_CHAMBER_IS_3 ? 3 : AUTO_CHAMBER_IS_4 ? 4 : 5
     };
     uint8_t fanState = 0;
 
     HOTEND_LOOP()
       if (current_temperature[e] > EXTRUDER_AUTO_FAN_TEMPERATURE)
         SBI(fanState, pgm_read_byte(&fanBit[e]));
+    if (current_temperature_chamber > EXTRUDER_AUTO_FAN_TEMPERATURE)
+      SBI(fanState, pgm_read_byte(&fanBit[5]));
 
     uint8_t fanDone = 0;
     for (uint8_t f = 0; f < COUNT(fanPin); f++) {
   }
 #endif // HAS_TEMP_BED
 
+#if HAS_TEMP_CHAMBER
+  // Derived from RepRap FiveD extruder::getTemperature()
+  // For chamber temperature measurement.
+  float Temperature::analog2tempChamber(const int raw) {
+    #if ENABLED(CHAMBER_USES_THERMISTOR)
+      float celsius = 0;
+      byte i;
+
+      for (i = 1; i < CHAMBERTEMPTABLE_LEN; i++) {
+        if (PGM_RD_W(CHAMBERTEMPTABLE[i][0]) > raw) {
+          celsius  = PGM_RD_W(CHAMBERTEMPTABLE[i - 1][1]) +
+                     (raw - PGM_RD_W(CHAMBERTEMPTABLE[i - 1][0])) *
+                     (float)(PGM_RD_W(CHAMBERTEMPTABLE[i][1]) - PGM_RD_W(CHAMBERTEMPTABLE[i - 1][1])) /
+                     (float)(PGM_RD_W(CHAMBERTEMPTABLE[i][0]) - PGM_RD_W(CHAMBERTEMPTABLE[i - 1][0]));
+          break;
+        }
+      }
+
+      // Overflow: Set to last value in the table
+      if (i == CHAMBERTEMPTABLE_LEN) celsius = PGM_RD_W(CHAMBERTEMPTABLE[i - 1][1]);
+
+      return celsius;
+
+    #elif defined(CHAMBER_USES_AD595)
+
+      return ((raw * ((5.0 * 100.0) / 1024.0) / OVERSAMPLENR) * (TEMP_SENSOR_AD595_GAIN)) + TEMP_SENSOR_AD595_OFFSET;
+
+    #else
+
+      UNUSED(raw);
+      return 0;
+
+    #endif
+  }
+#endif // HAS_TEMP_CHAMBER
+
 /**
  * Get the raw values into the actual temperatures.
  * The raw values are created in interrupt context,
   #if HAS_TEMP_BED
     current_temperature_bed = Temperature::analog2tempBed(current_temperature_bed_raw);
   #endif
+  #if HAS_TEMP_CHAMBER
+    current_temperature_chamber = Temperature::analog2tempChamber(current_temperature_chamber_raw);
+  #endif
   #if ENABLED(TEMP_SENSOR_1_AS_REDUNDANT)
     redundant_temperature = Temperature::analog2temp(redundant_temperature_raw, 1);
   #endif
     inited = true;
   #endif
 
-  #if MB(RUMBA) && (TEMP_SENSOR_0 == -1 || TEMP_SENSOR_1 == -1 || TEMP_SENSOR_2 == -1 || TEMP_SENSOR_BED == -1)
+  #if MB(RUMBA) && (TEMP_SENSOR_0 == -1 || TEMP_SENSOR_1 == -1 || TEMP_SENSOR_2 == -1 || TEMP_SENSOR_BED == -1 || TEMP_SENSOR_CHAMBER == -1)
     // Disable RUMBA JTAG in case the thermocouple extension is plugged on top of JTAG connector
     MCUCR = _BV(JTD);
     MCUCR = _BV(JTD);
   #if HAS_TEMP_BED
     HAL_ANALOG_SELECT(TEMP_BED_PIN);
   #endif
+  #if HAS_TEMP_CHAMBER
+    HAL_ANALOG_SELECT(TEMP_CHAMBER_PIN);
+  #endif
   #if ENABLED(FILAMENT_WIDTH_SENSOR)
     HAL_ANALOG_SELECT(FILWIDTH_PIN);
   #endif
       SET_OUTPUT(E4_AUTO_FAN_PIN);
     #endif
   #endif
+  #if HAS_AUTO_CHAMBER_FAN && !AUTO_CHAMBER_IS_0 && !AUTO_CHAMBER_IS_1 && !AUTO_CHAMBER_IS_2 && !AUTO_CHAMBER_IS_3 && ! AUTO_CHAMBER_IS_4
+    #if CHAMBER_AUTO_FAN_PIN == FAN1_PIN
+      SET_OUTPUT(CHAMBER_AUTO_FAN_PIN);
+      #if ENABLED(FAST_PWM_FAN)
+        setPwmFrequency(CHAMBER_AUTO_FAN_PIN, 1); // No prescaling. Pwm frequency = F_CPU/256/8
+      #endif
+    #else
+      SET_OUTPUT(CHAMBER_AUTO_FAN_PIN);
+    #endif
+  #endif
 
   // Wait for temperature measurement to settle
   delay(250);
     #endif
   #endif
   current_temperature_bed_raw = raw_temp_bed_value;
+  current_temperature_chamber_raw = raw_temp_chamber_value;
   temp_meas_ready = true;
 }
 
         break;
     #endif
 
+    #if HAS_TEMP_CHAMBER
+      case PrepareTemp_CHAMBER:
+        HAL_START_ADC(TEMP_CHAMBER_PIN);
+        break;
+      case MeasureTemp_CHAMBER:
+        raw_temp_chamber_value += ADC;
+        break;
+    #endif
+
     #if HAS_TEMP_1
       case PrepareTemp_1:
         HAL_START_ADC(TEMP_1_PIN);
 
     ZERO(raw_temp_value);
     raw_temp_bed_value = 0;
+    raw_temp_chamber_value = 0;
 
     #define TEMPDIR(N) ((HEATER_##N##_RAW_LO_TEMP) > (HEATER_##N##_RAW_HI_TEMP) ? -1 : 1)
 
     #if NUM_SERIAL > 1
       , const int8_t port=-1
     #endif
-    , const int8_t e=-2
+    , const int8_t e=-3
   ) {
-    #if !(HAS_TEMP_BED && HAS_TEMP_HOTEND) && HOTENDS <= 1
+    #if !(HAS_TEMP_BED && HAS_TEMP_HOTEND && HAS_TEMP_CHAMBER) && HOTENDS <= 1
       UNUSED(e);
     #endif
 
     SERIAL_PROTOCOLCHAR_P(port, ' ');
     SERIAL_PROTOCOLCHAR_P(port,
-      #if HAS_TEMP_BED && HAS_TEMP_HOTEND
+      #if HAS_TEMP_CHAMBER && HAS_TEMP_BED && HAS_TEMP_HOTEND
+        e == -2 ? 'C' : e == -1 ? 'B' : 'T'
+      #elif HAS_TEMP_BED && HAS_TEMP_HOTEND
         e == -1 ? 'B' : 'T'
       #elif HAS_TEMP_HOTEND
         'T'
         , -1 // BED
       );
     #endif
+    #if HAS_TEMP_CHAMBER
+      print_heater_state(degChamber(), 0
+        #if ENABLED(SHOW_TEMP_ADC_VALUES)
+          , rawChamberTemp()
+        #endif
+        , -2 // CHAMBER
+      );
+    #endif
     #if HOTENDS > 1
       HOTEND_LOOP() print_heater_state(degHotend(e), degTargetHotend(e)
         #if ENABLED(SHOW_TEMP_ADC_VALUES)

Marlin/src/module/temperature.h

     PrepareTemp_BED,
     MeasureTemp_BED,
   #endif
+  #if HAS_TEMP_CHAMBER
+    PrepareTemp_CHAMBER,
+    MeasureTemp_CHAMBER,
+  #endif
   #if ENABLED(FILAMENT_WIDTH_SENSOR)
     Prepare_FILWIDTH,
     Measure_FILWIDTH,
   public:
 
     static float current_temperature[HOTENDS],
+                 current_temperature_chamber,
                  current_temperature_bed;
     static int16_t current_temperature_raw[HOTENDS],
                    target_temperature[HOTENDS],
+                   current_temperature_chamber_raw,
                    current_temperature_bed_raw;
 
     #if ENABLED(AUTO_POWER_E_FANS)
     #endif
 
     static uint16_t raw_temp_value[MAX_EXTRUDERS],
+                    raw_temp_chamber_value,
                     raw_temp_bed_value;
 
     // Init min and max temp with extreme values to prevent false errors during startup
     #if HAS_TEMP_BED
       static float analog2tempBed(const int raw);
     #endif
+    #if HAS_TEMP_CHAMBER
+      static float analog2tempChamber(const int raw);
+    #endif
 
     /**
      * Called from the Temperature ISR
       return current_temperature[HOTEND_INDEX];
     }
     FORCE_INLINE static float degBed() { return current_temperature_bed; }
+    FORCE_INLINE static float degChamber() { return current_temperature_chamber; }
 
     #if ENABLED(SHOW_TEMP_ADC_VALUES)
       FORCE_INLINE static int16_t rawHotendTemp(const uint8_t e) {
         return current_temperature_raw[HOTEND_INDEX];
       }
       FORCE_INLINE static int16_t rawBedTemp() { return current_temperature_bed_raw; }
+      FORCE_INLINE static int16_t rawChamberTemp() { return current_temperature_chamber_raw; }
     #endif
 
     FORCE_INLINE static int16_t degTargetHotend(const uint8_t e) {

Marlin/src/module/thermistor/thermistor_20.h

   #define HEATER_BED_RAW_HI_TEMP 16383
   #define HEATER_BED_RAW_LO_TEMP 0
 #endif
+#if THERMISTORCHAMBER == 20
+  #define HEATER_CHAMBER_RAW_HI_TEMP 16383
+  #define HEATER_CHAMBER_RAW_LO_TEMP 0
+#endif
 const short temptable_20[][2] PROGMEM = {
   { OV(  0),    0 },
   { OV(227),    1 },

Marlin/src/module/thermistor/thermistors.h

 #define OVERSAMPLENR 16
 #define OV(N) int16_t((N) * (OVERSAMPLENR))
 
-#define ANY_THERMISTOR_IS(n) (THERMISTORHEATER_0 == n || THERMISTORHEATER_1 == n || THERMISTORHEATER_2 == n || THERMISTORHEATER_3 == n || THERMISTORHEATER_4 == n || THERMISTORBED == n)
+#define ANY_THERMISTOR_IS(n) (THERMISTORHEATER_0 == n || THERMISTORHEATER_1 == n || THERMISTORHEATER_2 == n || THERMISTORHEATER_3 == n || THERMISTORHEATER_4 == n || THERMISTORBED == n || THERMISTORCHAMBER == n)
 
 // Pt1000 and Pt100 handling
 //
   #endif
 #endif
 
+#ifdef THERMISTORCHAMBER
+  #define CHAMBERTEMPTABLE TT_NAME(THERMISTORCHAMBER)
+  #define CHAMBERTEMPTABLE_LEN COUNT(CHAMBERTEMPTABLE)
+#else
+  #ifdef CHAMBER_USES_THERMISTOR
+    #error "No chamber thermistor table specified"
+  #endif
+#endif
+
 // Set the high and low raw values for the heaters
 // For thermistors the highest temperature results in the lowest ADC value
 // For thermocouples the highest temperature results in the highest ADC value
     #define HEATER_BED_RAW_LO_TEMP 0
   #endif
 #endif
+#ifndef HEATER_CHAMBER_RAW_HI_TEMP
+  #ifdef CHAMBER_USES_THERMISTOR
+    #define HEATER_CHAMBER_RAW_HI_TEMP 0
+    #define HEATER_CHAMBER_RAW_LO_TEMP 16383
+  #else
+    #define HEATER_CHAMBER_RAW_HI_TEMP 16383
+    #define HEATER_CHAMBER_RAW_LO_TEMP 0
+  #endif
+#endif
 
 #endif // THERMISTORS_H_

Marlin/src/pins/pins.h

     #define E4_AUTO_FAN_PIN -1
   #endif
 #endif
+#ifndef CHAMBER_AUTO_FAN_PIN
+  #ifdef ORIG_CHAMBER_AUTO_FAN_PIN
+    #define CHAMBER_AUTO_FAN_PIN ORIG_CHAMBER_AUTO_FAN_PIN
+  #else
+    #define CHAMBER_AUTO_FAN_PIN -1
+  #endif
+#endif
 
 // List of pins which to ignore when asked to change by gcode, 0 and 1 are RX and TX, do not mess with those!
 #define _E0_PINS E0_STEP_PIN, E0_DIR_PIN, E0_ENABLE_PIN, E0_MS1_PIN, E0_MS2_PIN, E0_CS_PIN,

Marlin/src/pins/pinsDebug_list.h

 #if PIN_EXISTS(TEMP_CHAMBER) && TEMP_CHAMBER_PIN < NUM_ANALOG_INPUTS
   REPORT_NAME_ANALOG(__LINE__, TEMP_CHAMBER_PIN)
 #endif
-#if PIN_EXISTS(TEMP_X) && TEMP_X_PIN < NUM_ANALOG_INPUTS
-  REPORT_NAME_ANALOG(__LINE__, TEMP_X_PIN)
-#endif
 #if PIN_EXISTS(ADC_KEYPAD) && ADC_KEYPAD_PIN < NUM_ANALOG_INPUTS
   REPORT_NAME_ANALOG(__LINE__, ADC_KEYPAD_PIN)
 #endif
 #if PIN_EXISTS(CASE_LIGHT)
   REPORT_NAME_DIGITAL(__LINE__, CASE_LIGHT_PIN)
 #endif
+#if PIN_EXISTS(CHAMBER_AUTO_FAN)
+  REPORT_NAME_DIGITAL(__LINE__, CHAMBER_AUTO_FAN_PIN)
+#endif
 #if PIN_EXISTS(CONTROLLER_FAN)
   REPORT_NAME_DIGITAL(__LINE__, CONTROLLER_FAN_PIN)
 #endif

Marlin/src/pins/pins_RUMBA.h

 
 // optional for extruder 4 or chamber:
 //#define TEMP_X_PIN         12   // Analog Input (default connector for thermistor *T3* on rumba board is used)
+//#define TEMP_CHAMBER_PIN   12   // Analog Input (default connector for thermistor *T3* on rumba board is used)
 
 #if TEMP_SENSOR_BED == -1
   #define TEMP_BED_PIN      7   // Analog Input (connector *K3* on RUMBA thermocouple ADD ON is used <-- this can't be used when TEMP_SENSOR_2 is defined as thermocouple)