diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index 20c110ff7b..9d1118838a 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -330,6 +330,18 @@
#define EXTRUDER_RUNOUT_EXTRUDE 5 // (mm)
#endif
+/**
+ * Hotend Idle Timeout
+ * Prevent filament in the nozzle from charring and causing a critical jam.
+ */
+//#define HOTEND_IDLE_TIMEOUT
+#if ENABLED(HOTEND_IDLE_TIMEOUT)
+ #define HOTEND_IDLE_DURATION_SEC 5 // (minutes) Time without extruder movement to trigger protection
+ #define HOTEND_IDLE_MIN_TRIGGER 180 // (°C) Minimum temperature to enable hotend protection
+ #define HOTEND_IDLE_NOZZLE_TARGET 0 // (°C) Safe temperature for the nozzle after timeout
+ #define HOTEND_IDLE_BED_TARGET 0 // (°C) Safe temperature for the bed after timeout
+#endif
+
// @section temperature
// Calibration for AD595 / AD8495 sensor to adjust temperature measurements.
@@ -3308,7 +3320,7 @@
*/
//#define MMU_EXTRUDER_SENSOR
- #if ENABLED(MMU_EXTRUDER_SENSOR)
+ #if ENABLED(MMU_EXTRUDER_SENSOR)
#define MMU_LOADING_ATTEMPTS_NR 5 //max. number of attempts to load filament if first load fail
#endif
diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 2434df0ad4..3b07676840 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -159,6 +159,10 @@
#include "feature/runout.h"
#endif
+#if ENABLED(HOTEND_IDLE_TIMEOUT)
+ #include "feature/hotend_idle.h"
+#endif
+
#if ENABLED(TEMP_STAT_LEDS)
#include "feature/leds/tempstat.h"
#endif
@@ -527,6 +531,8 @@ inline void manage_inactivity(const bool ignore_stepper_queue=false) {
TERN_(AUTO_POWER_CONTROL, powerManager.check());
+ TERN_(HOTEND_IDLE_TIMEOUT, hotend_idle.check());
+
#if ENABLED(EXTRUDER_RUNOUT_PREVENT)
if (thermalManager.degHotend(active_extruder) > EXTRUDER_RUNOUT_MINTEMP
&& ELAPSED(ms, gcode.previous_move_ms + SEC_TO_MS(EXTRUDER_RUNOUT_SECONDS))
diff --git a/Marlin/src/feature/hotend_idle.cpp b/Marlin/src/feature/hotend_idle.cpp
new file mode 100644
index 0000000000..6b5d1b276d
--- /dev/null
+++ b/Marlin/src/feature/hotend_idle.cpp
@@ -0,0 +1,89 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ *
+ */
+
+/**
+ * Hotend Idle Timeout
+ * Prevent filament in the nozzle from charring and causing a critical jam.
+ */
+
+#include "../inc/MarlinConfig.h"
+
+#if ENABLED(HOTEND_IDLE_TIMEOUT)
+
+#include "hotend_idle.h"
+#include "../gcode/gcode.h"
+
+#include "../module/temperature.h"
+#include "../module/motion.h"
+#include "../lcd/ultralcd.h"
+
+extern HotendIdleProtection hotend_idle;
+
+millis_t HotendIdleProtection::next_protect_ms = 0;
+
+void HotendIdleProtection::check_hotends(const millis_t &ms) {
+ bool do_prot = false;
+ HOTEND_LOOP() {
+ if (thermalManager.degHotendNear(e, HOTEND_IDLE_MIN_TRIGGER)) {
+ do_prot = true; break;
+ }
+ }
+ if (bool(next_protect_ms) != do_prot)
+ next_protect_ms = do_prot ? ms + hp_interval : 0;
+}
+
+void HotendIdleProtection::check_e_motion(const millis_t &ms) {
+ static float old_e_position = 0;
+ if (old_e_position != current_position.e) {
+ old_e_position = current_position.e; // Track filament motion
+ if (next_protect_ms) // If some heater is on then...
+ next_protect_ms = ms + hp_interval; // ...delay the timeout till later
+ }
+}
+
+void HotendIdleProtection::check() {
+ const millis_t ms = millis(); // Shared millis
+
+ check_hotends(ms); // Any hotends need protection?
+ check_e_motion(ms); // Motion will protect them
+
+ // Hot and not moving for too long...
+ if (next_protect_ms && ELAPSED(ms, next_protect_ms))
+ timed_out();
+}
+
+// Lower (but don't raise) hotend / bed temperatures
+void HotendIdleProtection::timed_out() {
+ next_protect_ms = 0;
+ SERIAL_ECHOLNPGM("Hotend Idle Timeout");
+ LCD_MESSAGEPGM(MSG_HOTEND_IDLE_TIMEOUT);
+ HOTEND_LOOP() {
+ if ((HOTEND_IDLE_NOZZLE_TARGET) < thermalManager.degTargetHotend(e))
+ thermalManager.setTargetHotend(HOTEND_IDLE_NOZZLE_TARGET, e);
+ }
+ #if HAS_HEATED_BED
+ if ((HOTEND_IDLE_BED_TARGET) < thermalManager.degTargetBed())
+ thermalManager.setTargetBed(HOTEND_IDLE_BED_TARGET);
+ #endif
+}
+
+#endif // HOTEND_IDLE_TIMEOUT
diff --git a/Marlin/src/feature/hotend_idle.h b/Marlin/src/feature/hotend_idle.h
new file mode 100644
index 0000000000..298439da29
--- /dev/null
+++ b/Marlin/src/feature/hotend_idle.h
@@ -0,0 +1,37 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ *
+ */
+#pragma once
+
+#include "../core/millis_t.h"
+
+class HotendIdleProtection {
+public:
+ static void check();
+private:
+ static constexpr millis_t hp_interval = SEC_TO_MS(HOTEND_IDLE_DURATION_SEC);
+ static millis_t next_protect_ms;
+ static void check_hotends(const millis_t &ms);
+ static void check_e_motion(const millis_t &ms);
+ static void timed_out();
+};
+
+extern HotendIdleProtection hotend_idle;
diff --git a/Marlin/src/inc/Conditionals_LCD.h b/Marlin/src/inc/Conditionals_LCD.h
index 47a94d0074..11cf582637 100644
--- a/Marlin/src/inc/Conditionals_LCD.h
+++ b/Marlin/src/inc/Conditionals_LCD.h
@@ -414,6 +414,7 @@
#undef MIXING_EXTRUDER
#undef MK2_MULTIPLEXER
#undef PRUSA_MMU2
+ #undef HOTEND_IDLE_TIMEOUT
#endif
#if ENABLED(SWITCHING_EXTRUDER) // One stepper for every two EXTRUDERS
diff --git a/Marlin/src/lcd/language/language_en.h b/Marlin/src/lcd/language/language_en.h
index 3ee5bea6e4..b8013bf16c 100644
--- a/Marlin/src/lcd/language/language_en.h
+++ b/Marlin/src/lcd/language/language_en.h
@@ -488,6 +488,7 @@ namespace Language_en {
PROGMEM Language_Str MSG_INFO_PROTOCOL = _UxGT("Protocol");
PROGMEM Language_Str MSG_INFO_RUNAWAY_OFF = _UxGT("Runaway Watch: OFF");
PROGMEM Language_Str MSG_INFO_RUNAWAY_ON = _UxGT("Runaway Watch: ON");
+ PROGMEM Language_Str MSG_HOTEND_IDLE_TIMEOUT = _UxGT("Hotend Idle Timeout");
PROGMEM Language_Str MSG_CASE_LIGHT = _UxGT("Case Light");
PROGMEM Language_Str MSG_CASE_LIGHT_BRIGHTNESS = _UxGT("Light Brightness");
diff --git a/Marlin/src/module/temperature.h b/Marlin/src/module/temperature.h
index 155644e7f8..b2c5497b00 100644
--- a/Marlin/src/module/temperature.h
+++ b/Marlin/src/module/temperature.h
@@ -612,6 +612,10 @@ class Temperature {
return degTargetHotend(e) > TEMP_HYSTERESIS && ABS(degHotend(e) - degTargetHotend(e)) > TEMP_HYSTERESIS;
}
+ FORCE_INLINE static bool degHotendNear(const uint8_t e, const float &temp) {
+ return ABS(degHotend(e) - temp) < (TEMP_HYSTERESIS);
+ }
+
#endif // HOTENDS
#if HAS_HEATED_BED
@@ -650,6 +654,10 @@ class Temperature {
static void wait_for_bed_heating();
+ FORCE_INLINE static bool degBedNear(const float &temp) {
+ return ABS(degBed() - temp) < (TEMP_BED_HYSTERESIS);
+ }
+
#endif // HAS_HEATED_BED
#if HAS_TEMP_PROBE
diff --git a/buildroot/share/tests/esp32-tests b/buildroot/share/tests/esp32-tests
index 37a67fcae6..ccc01a1c1c 100755
--- a/buildroot/share/tests/esp32-tests
+++ b/buildroot/share/tests/esp32-tests
@@ -31,7 +31,8 @@ opt_set X_HARDWARE_SERIAL Serial1
opt_set Y_HARDWARE_SERIAL Serial1
opt_set Z_HARDWARE_SERIAL Serial1
opt_set E0_HARDWARE_SERIAL Serial1
-exec_test $1 $2 "ESP32 with TMC Hardware Serial"
+opt_enable HOTEND_IDLE_TIMEOUT
+exec_test $1 $2 "ESP32, TMC HW Serial, Hotend Idle"
# cleanup
restore_configs