Use SoC temperature sensor

Marlin/Configuration.h

@@ -456,6 +456,18 @@
  *
  * Temperature sensors available:
  *
+ *  Board (SoC) Internal Temperature Sensor - IMPORTANT: Only available for TEMP_SENSOR_BOARD
+ *  -------
+ *  -100 : Use chip internal temperature sensor
+ *
+ *  NOTE: The use of the chip internal temperature sensor is to measure the silicon temperature.
+ *        It is in NO WAY meant to be an accurate reading of the ambient temperature.
+ *        Can only be used with TEMP_SENSOR_BOARD.
+ *
+ *  NOTE: Requires TEMP_INTERNAL_SENSOR(RAW) macro to convert the ADC value of the TEMP_BOARD_PIN to the temperature.
+ *        HAL\STM32\internal_temp.h provides this macro for STM32 HAL using ATEMP pin and the specs of various STM32 chips.
+ *        Therefore, defining TEMP_SENSOR_BOARD -100 on stm32_variant boards is the only step required to use the internal sensor of the STM32.
+ *
  *  SPI RTD/Thermocouple Boards - IMPORTANT: Read the NOTE below!
  *  -------
  *    -5 : MAX31865 with Pt100/Pt1000, 2, 3, or 4-wire  (only for sensors 0-1)

Marlin/Configuration_adv.h

@@ -276,9 +276,7 @@
   #define THERMAL_PROTECTION_BOARD   // Halt the printer if the board sensor leaves the temp range below.
   #define BOARD_MINTEMP           8  // (°C)
   #define BOARD_MAXTEMP          70  // (°C)
-  #ifndef TEMP_BOARD_PIN
-    //#define TEMP_BOARD_PIN -1      // Board temp sensor pin, if not set in pins file.
-  #endif
+  //#define TEMP_BOARD_PIN -1        // Board temp sensor pin override.
 #endif
 
 /**

Marlin/src/HAL/STM32/HAL.h

@@ -28,6 +28,7 @@
 #include "../shared/Marduino.h"
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
+#include "internal_temp.h"
 #include "fastio.h"
 #include "Servo.h"
 #include "MarlinSerial.h"

Marlin/src/HAL/STM32/inc/SanityCheck.h

@@ -51,6 +51,10 @@
   #error "TFT_COLOR_UI, TFT_LVGL_UI and TFT_CLASSIC_UI are currently only supported on STM32H7, STM32F4 and STM32F1 hardware."
 #endif
 
+#if TEMP_SENSOR_BOARD_IS_INTERNAL && defined(ATEMP) && TEMP_BOARD_PIN != ATEMP
+  #error "TEMP_SENSOR_BOARD -100 requires 'TEMP_BOARD_PIN ATEMP' on STM32."
+#endif
+
 /**
  * Check for common serial pin conflicts
  */

Marlin/src/inc/Conditionals_adv.h

@@ -280,9 +280,9 @@
 #define _SENSOR_IS(I,N) || (TEMP_SENSOR(N) == I)
 #define _E_SENSOR_IS(I,N) _SENSOR_IS(N,I)
 #define ANY_E_SENSOR_IS(N) (0 REPEAT2(HOTENDS, _E_SENSOR_IS, N))
-#define ANY_THERMISTOR_IS(N) ( ANY_E_SENSOR_IS(N) \
-  _SENSOR_IS(N,BED) _SENSOR_IS(N,PROBE) _SENSOR_IS(N,CHAMBER) \
-  _SENSOR_IS(N,COOLER) _SENSOR_IS(N,BOARD) _SENSOR_IS(N,REDUNDANT) )
+#define ANY_EXT_THERMISTOR_IS(N) ( ANY_E_SENSOR_IS(N) _SENSOR_IS(N,REDUNDANT) \
+  _SENSOR_IS(N,BED) _SENSOR_IS(N,PROBE) _SENSOR_IS(N,CHAMBER) _SENSOR_IS(N,COOLER) )
+#define ANY_THERMISTOR_IS(N) ( ANY_EXT_THERMISTOR_IS(N) _SENSOR_IS(N,BOARD) )
 
 #if ANY_THERMISTOR_IS(1000)
   #define HAS_USER_THERMISTORS 1
@@ -740,7 +740,9 @@
   #endif
 #endif
 
-#if TEMP_SENSOR_BOARD == -4
+#if TEMP_SENSOR_BOARD == -100
+  #define TEMP_SENSOR_BOARD_IS_INTERNAL 1
+#elif TEMP_SENSOR_BOARD == -4
   #define TEMP_SENSOR_BOARD_IS_AD8495 1
 #elif TEMP_SENSOR_BOARD == -3
   #error "MAX31855 Thermocouples (-3) not supported for TEMP_SENSOR_BOARD."

Marlin/src/inc/SanityCheck.h

@@ -736,6 +736,11 @@ static_assert(COUNT(arm) == LOGICAL_AXES, "AXIS_RELATIVE_MODES must contain " _L
 #undef _ISMAX_1
 #undef _ISSNS_1
 
+// Internal Temperature Sensor
+#if ANY_EXT_THERMISTOR_IS(-100)
+  #error "Board Internal Temperature Sensor (-100) is only supported for TEMP_SENSOR_BOARD."
+#endif
+
 /**
  * Hephestos 2 Heated Bed Kit requirements
  */
@@ -2727,6 +2732,8 @@ static_assert(X_MAX_LENGTH >= X_BED_SIZE, "Movement bounds (X_MIN_POS, X_MAX_POS
     #error "TEMP_SENSOR_BOARD requires TEMP_BOARD_PIN."
   #elif ENABLED(THERMAL_PROTECTION_BOARD) && (!defined(BOARD_MINTEMP) || !defined(BOARD_MAXTEMP))
     #error "THERMAL_PROTECTION_BOARD requires BOARD_MINTEMP and BOARD_MAXTEMP."
+  #elif TEMP_SENSOR_BOARD_IS_INTERNAL && !defined(TEMP_INTERNAL_SENSOR)
+    #error "TEMP_SENSOR_BOARD -100 requires TEMP_INTERNAL_SENSOR(RAW) to be defined. It may not be implemented for your specific board."
   #endif
 #elif CONTROLLER_FAN_MIN_BOARD_TEMP
   #error "CONTROLLER_FAN_MIN_BOARD_TEMP requires TEMP_SENSOR_BOARD."

Marlin/src/module/temperature.cpp

@@ -2360,6 +2360,8 @@ void Temperature::task() {
       return TEMP_AD595(raw);
     #elif TEMP_SENSOR_BOARD_IS_AD8495
       return TEMP_AD8495(raw);
+    #elif TEMP_SENSOR_BOARD_IS_INTERNAL
+      return TEMP_INTERNAL_SENSOR(raw);
     #else
       UNUSED(raw);
       return 0;

Marlin/src/pins/lpc1769/pins_BTT_SKR_E3_TURBO.h

@@ -171,7 +171,10 @@
 #define TEMP_0_PIN                         P0_24
 #define TEMP_1_PIN                         P0_23
 #define TEMP_BED_PIN                       P0_25
-#define TEMP_BOARD_PIN                     P1_30  // Onboard thermistor, NTC100K
+
+#ifndef TEMP_BOARD_PIN
+  #define TEMP_BOARD_PIN                   P1_30  // Onboard thermistor, NTC100K
+#endif
 
 //
 // Heaters / Fans

Marlin/src/pins/rambo/pins_EINSY_RAMBO.h

@@ -118,10 +118,13 @@
 //
 #define TEMP_0_PIN                             0  // Analog Input, Header J2
 #define TEMP_1_PIN                             1  // Analog Input, Header J3
-#define TEMP_BOARD_PIN                        91  // Onboard thermistor, 100k TDK NTCG104LH104JT1
 #define TEMP_BED_PIN                           2  // Analog Input, Header J6
 #define TEMP_PROBE_PIN                         3  // Analog Input, Header J15
 
+#ifndef TEMP_BOARD_PIN
+  #define TEMP_BOARD_PIN                      91  // Onboard thermistor, 100k TDK NTCG104LH104JT1
+#endif
+
 //
 // Heaters / Fans
 //

Marlin/src/pins/sam/pins_DUE3DOM_MINI.h

@@ -69,7 +69,10 @@
 #define TEMP_0_PIN                             0  // Analog Input (HOTEND0 thermistor)
 #define TEMP_1_PIN                             2  // Analog Input (unused)
 #define TEMP_BED_PIN                           1  // Analog Input (BED thermistor)
-#define TEMP_BOARD_PIN                         5  // Analog Input (OnBoard thermistor beta 3950)
+
+#ifndef TEMP_BOARD_PIN
+  #define TEMP_BOARD_PIN                       5  // Analog Input (OnBoard thermistor beta 3950)
+#endif
 
 // SPI for MAX Thermocouple
 #if DISABLED(SDSUPPORT)

Marlin/src/pins/stm32f1/pins_ERYONE_ERY32_MINI.h

@@ -148,18 +148,22 @@
     #define E0_SLAVE_ADDRESS                   0
   #endif
 #endif
+
 //
 // Temperature Sensors
 //
-#define TEMP_BED_PIN                        PC2   //TB
-#define TEMP_0_PIN                          PC1   //TH1
-//#define TEMP_1_PIN                        PC3   //TH2
-#define TEMP_BOARD_PIN                      PC3
-#ifndef TEMP_SENSOR_BOARD
-  #define TEMP_SENSOR_BOARD                   13
-#endif
+#define TEMP_BED_PIN                        PC2   // TB
+#define TEMP_0_PIN                          PC1   // TH1
+//#define TEMP_1_PIN                        PC3   // TH2
 #define FIL_RUNOUT_PIN                      PA10  // MT_DET
 
+#ifndef TEMP_BOARD_PIN
+  #define TEMP_BOARD_PIN                    PC3
+#endif
+#if TEMP_BOARD_PIN == PC3 && TEMP_SENSOR_BOARD != 13
+  #warning "The built-in TEMP_SENSOR_BOARD is 13 for ERYONE Ery32 mini."
+#endif
+
 //
 // LCD Pins
 //

Marlin/src/pins/stm32f4/pins_BTT_BTT002_V1_0.h

@@ -160,10 +160,13 @@
 //
 #define TEMP_0_PIN                          PA2   // T0 <-> E0
 #define TEMP_1_PIN                          PA0   // T1 <-> E1
-#define TEMP_BOARD_PIN                      PC2   // Onboard thermistor, NTC100K
 #define TEMP_BED_PIN                        PA1   // T2 <-> Bed
 #define TEMP_PROBE_PIN                      PC3   // Shares J4 connector with PD1
 
+#ifndef TEMP_BOARD_PIN
+  #define TEMP_BOARD_PIN                    PC2   // Onboard thermistor, NTC100K
+#endif
+
 //
 // Heaters / Fans
 //