🚸 Up to 3 MAX Thermocouples (#24898)

Marlin/Configuration.h

@@ -564,6 +564,10 @@
   #define MAX31865_SENSOR_OHMS_1      100
   #define MAX31865_CALIBRATION_OHMS_1 430
 #endif
+#if TEMP_SENSOR_IS_MAX_TC(2)
+  #define MAX31865_SENSOR_OHMS_2      100
+  #define MAX31865_CALIBRATION_OHMS_2 430
+#endif
 
 #if HAS_E_TEMP_SENSOR
   #define TEMP_RESIDENCY_TIME         10  // (seconds) Time to wait for hotend to "settle" in M109

Marlin/Configuration_adv.h

@@ -175,6 +175,7 @@
 //#define TEMP_SENSOR_FORCE_HW_SPI                // Ignore SCK/MOSI/MISO pins; use CS and the default SPI bus.
 //#define MAX31865_SENSOR_WIRES_0 2               // (2-4) Number of wires for the probe connected to a MAX31865 board.
 //#define MAX31865_SENSOR_WIRES_1 2
+//#define MAX31865_SENSOR_WIRES_2 2
 
 //#define MAX31865_50HZ_FILTER                    // Use a 50Hz filter instead of the default 60Hz.
 //#define MAX31865_USE_READ_ERROR_DETECTION       // Treat value spikes (20°C delta in under 1s) as read errors.
@@ -185,6 +186,7 @@
 
 //#define MAX31865_WIRE_OHMS_0              0.95f // For 2-wire, set the wire resistances for more accurate readings.
 //#define MAX31865_WIRE_OHMS_1              0.0f
+//#define MAX31865_WIRE_OHMS_2              0.0f
 
 /**
  * Hephestos 2 24V heated bed upgrade kit.

Marlin/src/inc/Conditionals_adv.h

@@ -262,26 +262,72 @@
   #undef HEATER_1_MAXTEMP
 #endif
 
+#if TEMP_SENSOR_IS_MAX_TC(2)
+  #if TEMP_SENSOR_2 == -5
+    #define TEMP_SENSOR_2_IS_MAX31865 1
+    #define TEMP_SENSOR_2_MAX_TC_TMIN    0
+    #define TEMP_SENSOR_2_MAX_TC_TMAX 1024
+    #ifndef MAX31865_SENSOR_WIRES_2
+      #define MAX31865_SENSOR_WIRES_2 2
+    #endif
+    #ifndef MAX31865_WIRE_OHMS_2
+      #define MAX31865_WIRE_OHMS_2 0.0f
+    #endif
+  #elif TEMP_SENSOR_2 == -3
+    #define TEMP_SENSOR_2_IS_MAX31855 1
+    #define TEMP_SENSOR_2_MAX_TC_TMIN -270
+    #define TEMP_SENSOR_2_MAX_TC_TMAX 1800
+  #elif TEMP_SENSOR_2 == -2
+    #define TEMP_SENSOR_2_IS_MAX6675 1
+    #define TEMP_SENSOR_2_MAX_TC_TMIN    0
+    #define TEMP_SENSOR_2_MAX_TC_TMAX 1024
+  #endif
+
+  #if TEMP_SENSOR_2 != TEMP_SENSOR_0
+    #if   TEMP_SENSOR_2 == -5
+      #error "If MAX31865 Thermocouple (-5) is used for TEMP_SENSOR_2 then TEMP_SENSOR_0 must match."
+    #elif TEMP_SENSOR_2 == -3
+      #error "If MAX31855 Thermocouple (-3) is used for TEMP_SENSOR_2 then TEMP_SENSOR_0 must match."
+    #elif TEMP_SENSOR_2 == -2
+      #error "If MAX6675 Thermocouple (-2) is used for TEMP_SENSOR_2 then TEMP_SENSOR_0 must match."
+    #endif
+  #endif
+#elif TEMP_SENSOR_2 == -4
+  #define TEMP_SENSOR_2_IS_AD8495 1
+#elif TEMP_SENSOR_2 == -1
+  #define TEMP_SENSOR_2_IS_AD595 1
+#elif TEMP_SENSOR_2 > 0
+  #define TEMP_SENSOR_2_IS_THERMISTOR 1
+  #if TEMP_SENSOR_2 == 1000
+    #define TEMP_SENSOR_2_IS_CUSTOM 1
+  #elif TEMP_SENSOR_2 == 998 || TEMP_SENSOR_2 == 999
+    #define TEMP_SENSOR_2_IS_DUMMY 1
+  #endif
+#else
+  #undef HEATER_2_MINTEMP
+  #undef HEATER_2_MAXTEMP
+#endif
+
 #if TEMP_SENSOR_IS_MAX_TC(REDUNDANT)
   #if TEMP_SENSOR_REDUNDANT == -5
-    #if !REDUNDANT_TEMP_MATCH(SOURCE, E0) && !REDUNDANT_TEMP_MATCH(SOURCE, E1)
-      #error "MAX31865 Thermocouples (-5) not supported for TEMP_SENSOR_REDUNDANT_SOURCE other than TEMP_SENSOR_0/TEMP_SENSOR_1 (0/1)."
+    #if !REDUNDANT_TEMP_MATCH(SOURCE, E0) && !REDUNDANT_TEMP_MATCH(SOURCE, E1) && !REDUNDANT_TEMP_MATCH(SOURCE, E2)
+      #error "MAX31865 Thermocouples (-5) not supported for TEMP_SENSOR_REDUNDANT_SOURCE other than TEMP_SENSOR_0/TEMP_SENSOR_1/TEMP_SENSOR_2 (0/1/2)."
     #endif
 
     #define TEMP_SENSOR_REDUNDANT_IS_MAX31865    1
     #define TEMP_SENSOR_REDUNDANT_MAX_TC_TMIN    0
     #define TEMP_SENSOR_REDUNDANT_MAX_TC_TMAX 1024
   #elif TEMP_SENSOR_REDUNDANT == -3
-    #if !REDUNDANT_TEMP_MATCH(SOURCE, E0) && !REDUNDANT_TEMP_MATCH(SOURCE, E1)
-      #error "MAX31855 Thermocouples (-3) not supported for TEMP_SENSOR_REDUNDANT_SOURCE other than TEMP_SENSOR_0/TEMP_SENSOR_1 (0/1)."
+    #if !REDUNDANT_TEMP_MATCH(SOURCE, E0) && !REDUNDANT_TEMP_MATCH(SOURCE, E1) && !REDUNDANT_TEMP_MATCH(SOURCE, E2)
+      #error "MAX31855 Thermocouples (-3) not supported for TEMP_SENSOR_REDUNDANT_SOURCE other than TEMP_SENSOR_0/TEMP_SENSOR_1/TEMP_SENSOR_2 (0/1/2)."
     #endif
 
     #define TEMP_SENSOR_REDUNDANT_IS_MAX31855    1
     #define TEMP_SENSOR_REDUNDANT_MAX_TC_TMIN -270
     #define TEMP_SENSOR_REDUNDANT_MAX_TC_TMAX 1800
   #elif TEMP_SENSOR_REDUNDANT == -2
-    #if !REDUNDANT_TEMP_MATCH(SOURCE, E0) && !REDUNDANT_TEMP_MATCH(SOURCE, E1)
-      #error "MAX6675 Thermocouples (-2) not supported for TEMP_SENSOR_REDUNDANT_SOURCE other than TEMP_SENSOR_0/TEMP_SENSOR_1 (0/1)."
+    #if !REDUNDANT_TEMP_MATCH(SOURCE, E0) && !REDUNDANT_TEMP_MATCH(SOURCE, E1) && !REDUNDANT_TEMP_MATCH(SOURCE, E2)
+      #error "MAX6675 Thermocouples (-2) not supported for TEMP_SENSOR_REDUNDANT_SOURCE other than TEMP_SENSOR_0/TEMP_SENSOR_1/TEMP_SENSOR_2 (0/1/2)."
     #endif
 
     #define TEMP_SENSOR_REDUNDANT_IS_MAX6675     1
@@ -302,15 +348,21 @@
     #ifndef MAX31865_SENSOR_WIRES_1
       #define MAX31865_SENSOR_WIRES_1 2
     #endif
+  #elif REDUNDANT_TEMP_MATCH(SOURCE, E2)
+    #define TEMP_SENSOR_2_MAX_TC_TMIN TEMP_SENSOR_REDUNDANT_MAX_TC_TMIN
+    #define TEMP_SENSOR_2_MAX_TC_TMAX TEMP_SENSOR_REDUNDANT_MAX_TC_TMAX
+    #ifndef MAX31865_SENSOR_WIRES_2
+      #define MAX31865_SENSOR_WIRES_2 2
+    #endif
   #endif
 
-  #if (TEMP_SENSOR_IS_MAX_TC(0) && TEMP_SENSOR_REDUNDANT != TEMP_SENSOR_0) || (TEMP_SENSOR_IS_MAX_TC(1) && TEMP_SENSOR_REDUNDANT != TEMP_SENSOR_1)
+  #if (TEMP_SENSOR_IS_MAX_TC(0) && TEMP_SENSOR_REDUNDANT != TEMP_SENSOR_0) || (TEMP_SENSOR_IS_MAX_TC(1) && TEMP_SENSOR_REDUNDANT != TEMP_SENSOR_1) || (TEMP_SENSOR_IS_MAX_TC(2) && TEMP_SENSOR_REDUNDANT != TEMP_SENSOR_2)
     #if   TEMP_SENSOR_REDUNDANT == -5
-      #error "If MAX31865 Thermocouple (-5) is used for TEMP_SENSOR_0/TEMP_SENSOR_1 then TEMP_SENSOR_REDUNDANT must match."
+      #error "If MAX31865 Thermocouple (-5) is used for TEMP_SENSOR_0/TEMP_SENSOR_1/TEMP_SENSOR_2 then TEMP_SENSOR_REDUNDANT must match."
     #elif TEMP_SENSOR_REDUNDANT == -3
-      #error "If MAX31855 Thermocouple (-3) is used for TEMP_SENSOR_0/TEMP_SENSOR_1 then TEMP_SENSOR_REDUNDANT must match."
+      #error "If MAX31855 Thermocouple (-3) is used for TEMP_SENSOR_0/TEMP_SENSOR_1/TEMP_SENSOR_2 then TEMP_SENSOR_REDUNDANT must match."
     #elif TEMP_SENSOR_REDUNDANT == -2
-      #error "If MAX6675 Thermocouple (-2) is used for TEMP_SENSOR_0/TEMP_SENSOR_1 then TEMP_SENSOR_REDUNDANT must match."
+      #error "If MAX6675 Thermocouple (-2) is used for TEMP_SENSOR_0/TEMP_SENSOR_1/TEMP_SENSOR_2 then TEMP_SENSOR_REDUNDANT must match."
     #endif
   #endif
 #elif TEMP_SENSOR_REDUNDANT == -4
@@ -326,39 +378,19 @@
   #endif
 #endif
 
-#if TEMP_SENSOR_IS_MAX_TC(0) || TEMP_SENSOR_IS_MAX_TC(1) || TEMP_SENSOR_IS_MAX_TC(REDUNDANT)
+#if TEMP_SENSOR_IS_MAX_TC(0) || TEMP_SENSOR_IS_MAX_TC(1) || TEMP_SENSOR_IS_MAX_TC(2) || TEMP_SENSOR_IS_MAX_TC(REDUNDANT)
   #define HAS_MAX_TC 1
 #endif
-#if TEMP_SENSOR_0_IS_MAX6675 || TEMP_SENSOR_1_IS_MAX6675 || TEMP_SENSOR_REDUNDANT_IS_MAX6675
+#if TEMP_SENSOR_0_IS_MAX6675 || TEMP_SENSOR_1_IS_MAX6675 || TEMP_SENSOR_2_IS_MAX6675 || TEMP_SENSOR_REDUNDANT_IS_MAX6675
   #define HAS_MAX6675 1
 #endif
-#if TEMP_SENSOR_0_IS_MAX31855 || TEMP_SENSOR_1_IS_MAX31855 || TEMP_SENSOR_REDUNDANT_IS_MAX31855
+#if TEMP_SENSOR_0_IS_MAX31855 || TEMP_SENSOR_1_IS_MAX31855 || TEMP_SENSOR_2_IS_MAX31855 || TEMP_SENSOR_REDUNDANT_IS_MAX31855
   #define HAS_MAX31855 1
 #endif
-#if TEMP_SENSOR_0_IS_MAX31865 || TEMP_SENSOR_1_IS_MAX31865 || TEMP_SENSOR_REDUNDANT_IS_MAX31865
+#if TEMP_SENSOR_0_IS_MAX31865 || TEMP_SENSOR_1_IS_MAX31865 || TEMP_SENSOR_2_IS_MAX31865 || TEMP_SENSOR_REDUNDANT_IS_MAX31865
   #define HAS_MAX31865 1
 #endif
 
-#if TEMP_SENSOR_2 == -4
-  #define TEMP_SENSOR_2_IS_AD8495 1
-#elif TEMP_SENSOR_2 == -3
-  #error "MAX31855 Thermocouples (-3) not supported for TEMP_SENSOR_2."
-#elif TEMP_SENSOR_2 == -2
-  #error "MAX6675 Thermocouples (-2) not supported for TEMP_SENSOR_2."
-#elif TEMP_SENSOR_2 == -1
-  #define TEMP_SENSOR_2_IS_AD595 1
-#elif TEMP_SENSOR_2 > 0
-  #define TEMP_SENSOR_2_IS_THERMISTOR 1
-  #if TEMP_SENSOR_2 == 1000
-    #define TEMP_SENSOR_2_IS_CUSTOM 1
-  #elif TEMP_SENSOR_2 == 998 || TEMP_SENSOR_2 == 999
-    #define TEMP_SENSOR_2_IS_DUMMY 1
-  #endif
-#else
-  #undef HEATER_2_MINTEMP
-  #undef HEATER_2_MAXTEMP
-#endif
-
 #if TEMP_SENSOR_3 == -4
   #define TEMP_SENSOR_3_IS_AD8495 1
 #elif TEMP_SENSOR_3 == -3

Marlin/src/inc/Conditionals_post.h

@@ -723,19 +723,19 @@
         #define TEMP_0_SCK_PIN MAX31855_SCK_PIN
       #endif
 
-    #elif TEMP_SENSOR_1_IS_MAX31865
-      #if !PIN_EXISTS(TEMP_1_MISO) // DO
+    #elif TEMP_SENSOR_0_IS_MAX31865
+      #if !PIN_EXISTS(TEMP_0_MISO) // DO
         #if PIN_EXISTS(MAX31865_MISO)
-          #define TEMP_1_MISO_PIN MAX31865_MISO_PIN
+          #define TEMP_0_MISO_PIN MAX31865_MISO_PIN
         #elif PIN_EXISTS(MAX31865_DO)
-          #define TEMP_1_MISO_PIN MAX31865_DO_PIN
+          #define TEMP_0_MISO_PIN MAX31865_DO_PIN
         #endif
       #endif
-      #if !PIN_EXISTS(TEMP_1_SCK) && PIN_EXISTS(MAX31865_SCK)
-        #define TEMP_1_SCK_PIN MAX31865_SCK_PIN
+      #if !PIN_EXISTS(TEMP_0_SCK) && PIN_EXISTS(MAX31865_SCK)
+        #define TEMP_0_SCK_PIN MAX31865_SCK_PIN
       #endif
-      #if !PIN_EXISTS(TEMP_1_MOSI) && PIN_EXISTS(MAX31865_MOSI) // MOSI for '65 only
-        #define TEMP_1_MOSI_PIN MAX31865_MOSI_PIN
+      #if !PIN_EXISTS(TEMP_0_MOSI) && PIN_EXISTS(MAX31865_MOSI) // MOSI for '65 only
+        #define TEMP_0_MOSI_PIN MAX31865_MOSI_PIN
       #endif
     #endif
 
@@ -819,6 +819,75 @@
 
   #endif // TEMP_SENSOR_IS_MAX_TC(1)
 
+  #if TEMP_SENSOR_IS_MAX_TC(2) || (TEMP_SENSOR_IS_MAX_TC(REDUNDANT) && REDUNDANT_TEMP_MATCH(SOURCE, E2))
+
+    #if !PIN_EXISTS(TEMP_2_CS) // SS3, CS3
+      #if PIN_EXISTS(MAX6675_SS3)
+        #define TEMP_2_CS_PIN MAX6675_SS3_PIN
+      #elif PIN_EXISTS(MAX6675_CS)
+        #define TEMP_2_CS_PIN MAX6675_CS3_PIN
+      #elif PIN_EXISTS(MAX31855_SS3)
+        #define TEMP_2_CS_PIN MAX31855_SS3_PIN
+      #elif PIN_EXISTS(MAX31855_CS3)
+        #define TEMP_2_CS_PIN MAX31855_CS3_PIN
+      #elif PIN_EXISTS(MAX31865_SS3)
+        #define TEMP_2_CS_PIN MAX31865_SS3_PIN
+      #elif PIN_EXISTS(MAX31865_CS3)
+        #define TEMP_2_CS_PIN MAX31865_CS3_PIN
+      #endif
+    #endif
+
+    #if TEMP_SENSOR_2_IS_MAX6675
+      #if !PIN_EXISTS(TEMP_2_MISO) // DO
+        #if PIN_EXISTS(MAX6675_MISO)
+          #define TEMP_2_MISO_PIN MAX6675_MISO_PIN
+        #elif PIN_EXISTS(MAX6675_DO)
+          #define TEMP_2_MISO_PIN MAX6675_DO_PIN
+        #endif
+      #endif
+      #if !PIN_EXISTS(TEMP_2_SCK) && PIN_EXISTS(MAX6675_SCK)
+        #define TEMP_2_SCK_PIN MAX6675_SCK_PIN
+      #endif
+
+    #elif TEMP_SENSOR_2_IS_MAX31855
+      #if !PIN_EXISTS(TEMP_2_MISO) // DO
+        #if PIN_EXISTS(MAX31855_MISO)
+          #define TEMP_2_MISO_PIN MAX31855_MISO_PIN
+        #elif PIN_EXISTS(MAX31855_DO)
+          #define TEMP_2_MISO_PIN MAX31855_DO_PIN
+        #endif
+      #endif
+      #if !PIN_EXISTS(TEMP_2_SCK) && PIN_EXISTS(MAX31855_SCK)
+        #define TEMP_2_SCK_PIN MAX31855_SCK_PIN
+      #endif
+
+    #elif TEMP_SENSOR_2_IS_MAX31865
+      #if !PIN_EXISTS(TEMP_2_MISO) // DO
+        #if PIN_EXISTS(MAX31865_MISO)
+          #define TEMP_2_MISO_PIN MAX31865_MISO_PIN
+        #elif PIN_EXISTS(MAX31865_DO)
+          #define TEMP_2_MISO_PIN MAX31865_DO_PIN
+        #endif
+      #endif
+      #if !PIN_EXISTS(TEMP_2_SCK) && PIN_EXISTS(MAX31865_SCK)
+        #define TEMP_2_SCK_PIN MAX31865_SCK_PIN
+      #endif
+      #if !PIN_EXISTS(TEMP_2_MOSI) && PIN_EXISTS(MAX31865_MOSI) // MOSI for '65 only
+        #define TEMP_2_MOSI_PIN MAX31865_MOSI_PIN
+      #endif
+    #endif
+
+    // Software SPI - enable if MISO/SCK are defined.
+    #if PIN_EXISTS(TEMP_2_MISO) && PIN_EXISTS(TEMP_2_SCK) && DISABLED(TEMP_SENSOR_2_FORCE_HW_SPI)
+      #if TEMP_SENSOR_2_IS_MAX31865 && !PIN_EXISTS(TEMP_2_MOSI)
+        #error "TEMP_SENSOR_2 MAX31865 requires TEMP_2_MOSI_PIN defined for Software SPI. To use Hardware SPI instead, undefine MISO/SCK or enable TEMP_SENSOR_2_FORCE_HW_SPI."
+      #else
+        #define TEMP_SENSOR_2_HAS_SPI_PINS 1
+      #endif
+    #endif
+
+  #endif // TEMP_SENSOR_IS_MAX_TC(2)
+
   //
   // User-defined thermocouple libraries
   //

Marlin/src/inc/SanityCheck.h

@@ -416,17 +416,17 @@
 #elif defined(CHDK)
   #error "CHDK is now CHDK_PIN."
 #elif ANY_PIN( \
-        MAX6675_SS, MAX6675_SS2, MAX6675_CS, MAX6675_CS2, \
-        MAX31855_SS, MAX31855_SS2, MAX31855_CS, MAX31855_CS2, \
-        MAX31865_SS, MAX31865_SS2, MAX31865_CS, MAX31865_CS2)
-  #warning "MAX*_SS_PIN, MAX*_SS2_PIN, MAX*_CS_PIN, and MAX*_CS2_PIN are deprecated and will be removed in a future version. Please use TEMP_0_CS_PIN/TEMP_1_CS_PIN instead."
+        MAX6675_SS, MAX6675_SS2,  MAX6675_SS3, MAX6675_CS, MAX6675_CS2, MAX6675_CS3,\
+        MAX31855_SS, MAX31855_SS2, MAX31855_SS3, MAX31855_CS, MAX31855_CS2, MAX31855_CS3, \
+        MAX31865_SS, MAX31865_SS2, MAX31865_SS3, MAX31865_CS, MAX31865_CS2, MAX31865_CS3)
+  #warning "MAX*_SS_PIN, MAX*_SS2_PIN, MAX*_SS3_PIN, MAX*_CS_PIN, MAX*_CS2_PIN, and MAX*_CS3_PIN, are deprecated and will be removed in a future version. Please use TEMP_0_CS_PIN/TEMP_1_CS_PIN/TEMP_2_CS_PIN instead."
 #elif ANY_PIN(MAX6675_SCK, MAX31855_SCK, MAX31865_SCK)
-  #warning "MAX*_SCK_PIN is deprecated and will be removed in a future version. Please use TEMP_0_SCK_PIN/TEMP_1_SCK_PIN instead."
+  #warning "MAX*_SCK_PIN is deprecated and will be removed in a future version. Please use TEMP_0_SCK_PIN/TEMP_1_SCK_PIN/TEMP_2_SCK_PIN instead."
 #elif ANY_PIN(MAX6675_MISO, MAX6675_DO, MAX31855_MISO, MAX31855_DO, MAX31865_MISO, MAX31865_DO)
-  #warning "MAX*_MISO_PIN and MAX*_DO_PIN are deprecated and will be removed in a future version. Please use TEMP_0_MISO_PIN/TEMP_1_MISO_PIN instead."
+  #warning "MAX*_MISO_PIN and MAX*_DO_PIN are deprecated and will be removed in a future version. Please use TEMP_0_MISO_PIN/TEMP_1_MISO_PIN/TEMP_2_MISO_PIN instead."
 #elif PIN_EXISTS(MAX31865_MOSI)
-  #warning "MAX31865_MOSI_PIN is deprecated and will be removed in a future version. Please use TEMP_0_MOSI_PIN/TEMP_1_MOSI_PIN instead."
-#elif ANY_PIN(THERMO_CS1_PIN, THERMO_CS2_PIN, THERMO_DO_PIN, THERMO_SCK_PIN)
+  #warning "MAX31865_MOSI_PIN is deprecated and will be removed in a future version. Please use TEMP_0_MOSI_PIN/TEMP_1_MOSI_PIN/TEMP_2_MOSI_PIN instead."
+#elif ANY_PIN(THERMO_CS1_PIN, THERMO_CS2_PIN, THERMO_CS3_PIN, THERMO_DO_PIN, THERMO_SCK_PIN)
   #error "THERMO_*_PIN is now TEMP_n_CS_PIN, TEMP_n_SCK_PIN, TEMP_n_MOSI_PIN, TEMP_n_MISO_PIN."
 #elif defined(MAX31865_SENSOR_OHMS)
   #error "MAX31865_SENSOR_OHMS is now MAX31865_SENSOR_OHMS_0."
@@ -2340,6 +2340,13 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
     #error "MAX31865_SENSOR_OHMS_1 and MAX31865_CALIBRATION_OHMS_1 must be set if TEMP_SENSOR_1/TEMP_SENSOR_REDUNDANT is MAX31865."
   #endif
 #endif
+#if TEMP_SENSOR_2_IS_MAX31865 || (TEMP_SENSOR_REDUNDANT_IS_MAX31865 && REDUNDANT_TEMP_MATCH(SOURCE, E2))
+  #if !defined(MAX31865_SENSOR_WIRES_2) || !WITHIN(MAX31865_SENSOR_WIRES_2, 2, 4)
+    #error "MAX31865_SENSOR_WIRES_2 must be defined as an integer between 2 and 4."
+  #elif !defined(MAX31865_SENSOR_OHMS_2) || !defined(MAX31865_CALIBRATION_OHMS_2)
+    #error "MAX31865_SENSOR_OHMS_2 and MAX31865_CALIBRATION_OHMS_2 must be set if TEMP_SENSOR_2/TEMP_SENSOR_REDUNDANT is MAX31865."
+  #endif
+#endif
 
 /**
  * Redundant temperature sensor config

Marlin/src/module/temperature.cpp

@@ -113,13 +113,16 @@
 //  3. CS, MISO, and SCK pins w/ FORCE_HW_SPI:  Hardware SPI on the default bus, ignoring MISO, SCK.
 //
 #if TEMP_SENSOR_IS_ANY_MAX_TC(0) && TEMP_SENSOR_0_HAS_SPI_PINS && DISABLED(TEMP_SENSOR_FORCE_HW_SPI)
-    #define TEMP_SENSOR_0_USES_SW_SPI 1
+  #define TEMP_SENSOR_0_USES_SW_SPI 1
 #endif
 #if TEMP_SENSOR_IS_ANY_MAX_TC(1) && TEMP_SENSOR_1_HAS_SPI_PINS && DISABLED(TEMP_SENSOR_FORCE_HW_SPI)
-    #define TEMP_SENSOR_1_USES_SW_SPI 1
+  #define TEMP_SENSOR_1_USES_SW_SPI 1
+#endif
+#if TEMP_SENSOR_IS_ANY_MAX_TC(2) && TEMP_SENSOR_2_HAS_SPI_PINS && DISABLED(TEMP_SENSOR_FORCE_HW_SPI)
+  #define TEMP_SENSOR_2_USES_SW_SPI 1
 #endif
 
-#if (TEMP_SENSOR_0_USES_SW_SPI || TEMP_SENSOR_1_USES_SW_SPI) && !HAS_MAXTC_LIBRARIES
+#if (TEMP_SENSOR_0_USES_SW_SPI || TEMP_SENSOR_1_USES_SW_SPI || TEMP_SENSOR_2_USES_SW_SPI) && !HAS_MAXTC_LIBRARIES
   #include "../libs/private_spi.h"
   #define HAS_MAXTC_SW_SPI 1
 
@@ -130,12 +133,18 @@
     #if PIN_EXISTS(TEMP_0_MOSI)
       #define SW_SPI_MOSI_PIN TEMP_0_MOSI_PIN
     #endif
-  #else
+  #elif TEMP_SENSOR_1_USES_SW_SPI
     #define SW_SPI_SCK_PIN    TEMP_1_SCK_PIN
     #define SW_SPI_MISO_PIN   TEMP_1_MISO_PIN
     #if PIN_EXISTS(TEMP_1_MOSI)
       #define SW_SPI_MOSI_PIN TEMP_1_MOSI_PIN
     #endif
+  #elif TEMP_SENSOR_2_USES_SW_SPI
+    #define SW_SPI_SCK_PIN    TEMP_2_SCK_PIN
+    #define SW_SPI_MISO_PIN   TEMP_2_MISO_PIN
+    #if PIN_EXISTS(TEMP_2_MOSI)
+      #define SW_SPI_MOSI_PIN TEMP_2_MOSI_PIN
+    #endif
   #endif
   #ifndef SW_SPI_MOSI_PIN
     #define SW_SPI_MOSI_PIN   SD_MOSI_PIN
@@ -256,6 +265,9 @@ PGMSTR(str_t_heating_failed, STR_T_HEATING_FAILED);
     #if TEMP_SENSOR_IS_MAX(1, 6675)
       MAXTC_INIT(1, 6675);
     #endif
+    #if TEMP_SENSOR_IS_MAX(2, 6675)
+      MAXTC_INIT(2, 6675);
+    #endif
   #endif
 
   #if HAS_MAX31855_LIBRARY
@@ -265,12 +277,16 @@ PGMSTR(str_t_heating_failed, STR_T_HEATING_FAILED);
     #if TEMP_SENSOR_IS_MAX(1, 31855)
       MAXTC_INIT(1, 31855);
     #endif
+    #if TEMP_SENSOR_IS_MAX(2, 31855)
+      MAXTC_INIT(2, 31855);
+    #endif
   #endif
 
   // MAX31865 always uses a library, unlike '55 & 6675
   #if HAS_MAX31865
     #define _MAX31865_0_SW TEMP_SENSOR_0_USES_SW_SPI
     #define _MAX31865_1_SW TEMP_SENSOR_1_USES_SW_SPI
+    #define _MAX31865_2_SW TEMP_SENSOR_2_USES_SW_SPI
 
     #if TEMP_SENSOR_IS_MAX(0, 31865)
       MAXTC_INIT(0, 31865);
@@ -278,9 +294,13 @@ PGMSTR(str_t_heating_failed, STR_T_HEATING_FAILED);
     #if TEMP_SENSOR_IS_MAX(1, 31865)
       MAXTC_INIT(1, 31865);
     #endif
+    #if TEMP_SENSOR_IS_MAX(2, 31865)
+      MAXTC_INIT(2, 31865);
+    #endif
 
     #undef _MAX31865_0_SW
     #undef _MAX31865_1_SW
+    #undef _MAX31865_2_SW
   #endif
 
   #undef MAXTC_INIT
@@ -541,6 +561,7 @@ volatile bool Temperature::raw_temps_ready = false;
 #endif
 
 #if MAX_CONSECUTIVE_LOW_TEMPERATURE_ERROR_ALLOWED > 1
+  #define MULTI_MAX_CONSECUTIVE_LOW_TEMP_ERR 1
   uint8_t Temperature::consecutive_low_temperature_error[HOTENDS] = { 0 };
 #endif
 
@@ -1866,6 +1887,10 @@ void Temperature::task() {
       if (degHotend(1) > _MIN(HEATER_1_MAXTEMP, TEMP_SENSOR_1_MAX_TC_TMAX - 1.0)) max_temp_error(H_E1);
       if (degHotend(1) < _MAX(HEATER_1_MINTEMP, TEMP_SENSOR_1_MAX_TC_TMIN + .01)) min_temp_error(H_E1);
     #endif
+    #if TEMP_SENSOR_IS_MAX_TC(2)
+      if (degHotend(2) > _MIN(HEATER_2_MAXTEMP, TEMP_SENSOR_2_MAX_TC_TMAX - 1.0)) max_temp_error(H_E2);
+      if (degHotend(2) < _MAX(HEATER_2_MINTEMP, TEMP_SENSOR_2_MAX_TC_TMIN + .01)) min_temp_error(H_E2);
+    #endif
     #if TEMP_SENSOR_IS_MAX_TC(REDUNDANT)
       if (degRedundant() > TEMP_SENSOR_REDUNDANT_MAX_TC_TMAX - 1.0) max_temp_error(H_REDUNDANT);
       if (degRedundant() < TEMP_SENSOR_REDUNDANT_MAX_TC_TMIN + .01) min_temp_error(H_REDUNDANT);
@@ -2112,6 +2137,15 @@ void Temperature::task() {
       case 2:
         #if TEMP_SENSOR_2_IS_CUSTOM
           return user_thermistor_to_deg_c(CTI_HOTEND_2, raw);
+        #elif TEMP_SENSOR_IS_MAX_TC(2)
+          #if TEMP_SENSOR_0_IS_MAX31865
+            return TERN(LIB_INTERNAL_MAX31865,
+              max31865_2.temperature(raw),
+              max31865_2.temperature(MAX31865_SENSOR_OHMS_2, MAX31865_CALIBRATION_OHMS_2)
+            );
+          #else
+            return (int16_t)raw * 0.25;
+          #endif
         #elif TEMP_SENSOR_2_IS_AD595
           return TEMP_AD595(raw);
         #elif TEMP_SENSOR_2_IS_AD8495
@@ -2281,6 +2315,8 @@ void Temperature::task() {
       return TERN(TEMP_SENSOR_REDUNDANT_IS_MAX31865, max31865_0.temperature(raw), (int16_t)raw * 0.25);
     #elif TEMP_SENSOR_IS_MAX_TC(REDUNDANT) && REDUNDANT_TEMP_MATCH(SOURCE, E1)
       return TERN(TEMP_SENSOR_REDUNDANT_IS_MAX31865, max31865_1.temperature(raw), (int16_t)raw * 0.25);
+    #elif TEMP_SENSOR_IS_MAX_TC(REDUNDANT) && REDUNDANT_TEMP_MATCH(SOURCE, E2)
+      return TERN(TEMP_SENSOR_REDUNDANT_IS_MAX31865, max31865_2.temperature(raw), (int16_t)raw * 0.25);
     #elif TEMP_SENSOR_REDUNDANT_IS_THERMISTOR
       SCAN_THERMISTOR_TABLE(TEMPTABLE_REDUNDANT, TEMPTABLE_REDUNDANT_LEN);
     #elif TEMP_SENSOR_REDUNDANT_IS_AD595
@@ -2316,6 +2352,9 @@ void Temperature::updateTemperaturesFromRawValues() {
   #if TEMP_SENSOR_IS_MAX_TC(1)
     temp_hotend[1].setraw(READ_MAX_TC(1));
   #endif
+  #if TEMP_SENSOR_IS_MAX_TC(2)
+    temp_hotend[2].setraw(READ_MAX_TC(2));
+  #endif
   #if TEMP_SENSOR_IS_MAX_TC(REDUNDANT)
     temp_redundant.setraw(READ_MAX_TC(HEATER_ID(TEMP_SENSOR_REDUNDANT_SOURCE)));
   #endif
@@ -2347,9 +2386,14 @@ void Temperature::updateTemperaturesFromRawValues() {
         #else
           , TEMPDIR(1)
         #endif
-        #if HOTENDS > 2
+        #if TEMP_SENSOR_IS_ANY_MAX_TC(2)
+          , 0
+        #else
+          , TEMPDIR(2)
+        #endif
+        #if HOTENDS > 3
           #define _TEMPDIR(N) , TEMPDIR(N)
-          REPEAT_S(2, HOTENDS, _TEMPDIR)
+          REPEAT_S(3, HOTENDS, _TEMPDIR)
         #endif
       #endif
     };
@@ -2362,15 +2406,12 @@ void Temperature::updateTemperaturesFromRawValues() {
 
       const bool heater_on = temp_hotend[e].target > 0;
       if (heater_on && ((neg && r > temp_range[e].raw_min) || (pos && r < temp_range[e].raw_min))) {
-        #if MAX_CONSECUTIVE_LOW_TEMPERATURE_ERROR_ALLOWED > 1
-          if (++consecutive_low_temperature_error[e] >= MAX_CONSECUTIVE_LOW_TEMPERATURE_ERROR_ALLOWED)
-        #endif
-            min_temp_error((heater_id_t)e);
+        if (TERN1(MULTI_MAX_CONSECUTIVE_LOW_TEMP_ERR, ++consecutive_low_temperature_error[e] >= MAX_CONSECUTIVE_LOW_TEMPERATURE_ERROR_ALLOWED))
+          min_temp_error((heater_id_t)e);
+      }
+      else {
+        TERN_(MULTI_MAX_CONSECUTIVE_LOW_TEMP_ERR, consecutive_low_temperature_error[e] = 0);
       }
-      #if MAX_CONSECUTIVE_LOW_TEMPERATURE_ERROR_ALLOWED > 1
-        else
-          consecutive_low_temperature_error[e] = 0;
-      #endif
     }
 
   #endif // HAS_HOTEND
@@ -2432,6 +2473,9 @@ void Temperature::init() {
   #if TEMP_SENSOR_IS_ANY_MAX_TC(1) && PIN_EXISTS(TEMP_1_CS)
     OUT_WRITE(TEMP_1_CS_PIN, HIGH);
   #endif
+  #if TEMP_SENSOR_IS_ANY_MAX_TC(2) && PIN_EXISTS(TEMP_2_CS)
+    OUT_WRITE(TEMP_2_CS_PIN, HIGH);
+  #endif
 
   // Setup objects for library-based polling of MAX TCs
   #if HAS_MAXTC_LIBRARIES
@@ -2459,6 +2503,18 @@ void Temperature::init() {
         OPTARG(LIB_INTERNAL_MAX31865, MAX31865_SENSOR_OHMS_1, MAX31865_CALIBRATION_OHMS_1, MAX31865_WIRE_OHMS_1)
       );
     #endif
+
+    #if TEMP_SENSOR_IS_MAX(2, 6675) && HAS_MAX6675_LIBRARY
+      max6675_2.begin();
+    #elif TEMP_SENSOR_IS_MAX(2, 31855) && HAS_MAX31855_LIBRARY
+      max31855_2.begin();
+    #elif TEMP_SENSOR_IS_MAX(2, 31865)
+      max31865_2.begin(
+        MAX31865_WIRES(MAX31865_SENSOR_WIRES_2) // MAX31865_2WIRE, MAX31865_3WIRE, MAX31865_4WIRE
+        OPTARG(LIB_INTERNAL_MAX31865, MAX31865_SENSOR_OHMS_2, MAX31865_CALIBRATION_OHMS_2, MAX31865_WIRE_OHMS_2)
+      );
+    #endif
+
     #undef MAX31865_WIRES
     #undef _MAX31865_WIRES
   #endif
@@ -2491,6 +2547,15 @@ void Temperature::init() {
       #endif
     ));
   #endif
+  #if PIN_EXISTS(TEMP_2_TR_ENABLE)
+    OUT_WRITE(TEMP_2_TR_ENABLE_PIN, (
+      #if TEMP_SENSOR_IS_ANY_MAX_TC(2)
+        HIGH
+      #else
+        LOW
+      #endif
+    ));
+  #endif
 
   #if ENABLED(MPCTEMP)
     HOTEND_LOOP() temp_hotend[e].modeled_block_temp = NAN;
@@ -3009,25 +3074,29 @@ void Temperature::disable_all_heaters() {
       // Needed to return the correct temp when this is called between readings
       static raw_adc_t max_tc_temp_previous[MAX_TC_COUNT] = { 0 };
       #define THERMO_TEMP(I) max_tc_temp_previous[I]
-      #define THERMO_SEL(A,B) (hindex ? (B) : (A))
-      #define MAXTC_CS_WRITE(V) do{ switch (hindex) { case 1: WRITE(TEMP_1_CS_PIN, V); break; default: WRITE(TEMP_0_CS_PIN, V); } }while(0)
+      #define THERMO_SEL(A,B,C) (hindex > 1 ? (C) : hindex == 1 ? (B) : (A))
+      #define MAXTC_CS_WRITE(V) do{ switch (hindex) { case 1: WRITE(TEMP_1_CS_PIN, V); break; case 2: WRITE(TEMP_2_CS_PIN, V); break; default: WRITE(TEMP_0_CS_PIN, V); } }while(0)
     #else
       // When we have only 1 max tc, THERMO_SEL will pick the appropriate sensor
       // variable, and MAXTC_*() macros will be hardcoded to the correct CS pin.
       constexpr uint8_t hindex = 0;
       #define THERMO_TEMP(I) max_tc_temp
       #if TEMP_SENSOR_IS_ANY_MAX_TC(0)
-        #define THERMO_SEL(A,B) A
+        #define THERMO_SEL(A,B,C) A
         #define MAXTC_CS_WRITE(V)  WRITE(TEMP_0_CS_PIN, V)
-      #else
-        #define THERMO_SEL(A,B) B
+      #elif TEMP_SENSOR_IS_ANY_MAX_TC(1)
+        #define THERMO_SEL(A,B,C) B
         #define MAXTC_CS_WRITE(V)  WRITE(TEMP_1_CS_PIN, V)
+      #elif TEMP_SENSOR_IS_ANY_MAX_TC(2)
+        #define THERMO_SEL(A,B,C) C
+        #define MAXTC_CS_WRITE(V)  WRITE(TEMP_2_CS_PIN, V)
       #endif
     #endif
 
     static TERN(HAS_MAX31855, uint32_t, uint16_t) max_tc_temp = THERMO_SEL(
       TEMP_SENSOR_0_MAX_TC_TMAX,
-      TEMP_SENSOR_1_MAX_TC_TMAX
+      TEMP_SENSOR_1_MAX_TC_TMAX,
+      TEMP_SENSOR_2_MAX_TC_TMAX
     );
 
     static uint8_t max_tc_errors[MAX_TC_COUNT] = { 0 };
@@ -3062,17 +3131,17 @@ void Temperature::disable_all_heaters() {
       MAXTC_CS_WRITE(HIGH);  // Disable MAXTC
     #else
       #if HAS_MAX6675_LIBRARY
-        MAX6675 &max6675ref = THERMO_SEL(max6675_0, max6675_1);
+        MAX6675 &max6675ref = THERMO_SEL(max6675_0, max6675_1, max6675_2);
         max_tc_temp = max6675ref.readRaw16();
       #endif
 
       #if HAS_MAX31855_LIBRARY
-        MAX31855 &max855ref = THERMO_SEL(max31855_0, max31855_1);
+        MAX31855 &max855ref = THERMO_SEL(max31855_0, max31855_1, max31855_2);
         max_tc_temp = max855ref.readRaw32();
       #endif
 
       #if HAS_MAX31865
-        MAX31865 &max865ref = THERMO_SEL(max31865_0, max31865_1);
+        MAX31865 &max865ref = THERMO_SEL(max31865_0, max31865_1, max31865_2);
         max_tc_temp = TERN(LIB_INTERNAL_MAX31865, max865ref.readRaw(), max865ref.readRTD_with_Fault());
       #endif
     #endif
@@ -3117,7 +3186,7 @@ void Temperature::disable_all_heaters() {
         #endif
 
         // Set thermocouple above max temperature (TMAX)
-        max_tc_temp = THERMO_SEL(TEMP_SENSOR_0_MAX_TC_TMAX, TEMP_SENSOR_1_MAX_TC_TMAX) << (MAX_TC_DISCARD_BITS + 1);
+        max_tc_temp = THERMO_SEL(TEMP_SENSOR_0_MAX_TC_TMAX, TEMP_SENSOR_1_MAX_TC_TMAX, TEMP_SENSOR_2_MAX_TC_TMAX) << (MAX_TC_DISCARD_BITS + 1);
       }
     }
     else {
@@ -3155,6 +3224,10 @@ void Temperature::update_raw_temperatures() {
     temp_hotend[1].update();
   #endif
 
+  #if HAS_TEMP_ADC_2 && !TEMP_SENSOR_IS_MAX_TC(2)
+    temp_hotend[2].update();
+  #endif
+
   #if HAS_TEMP_ADC_REDUNDANT && !TEMP_SENSOR_IS_MAX_TC(REDUNDANT)
     temp_redundant.update();
   #endif