Add a global machine state

Marlin/src/MarlinCore.cpp

            SP_Z_LBL[] PROGMEM = " Z:",
            SP_E_LBL[] PROGMEM = " E:";
 
-bool Running = true;
+MarlinState marlin_state = MF_INITIALIZING;
 
 // For M109 and M190, this flag may be cleared (by M108) to exit the wait loop
 bool wait_for_heatup = true;
     SERIAL_ERROR_MSG(STR_ERR_STOPPED);
     LCD_MESSAGEPGM(MSG_STOPPED);
     safe_delay(350);       // allow enough time for messages to get out before stopping
-    Running = false;
+    marlin_state = MF_STOPPED;
   }
 }
 
     SETUP_RUN(max7219.init());
   #endif
 
+  marlin_state = MF_RUNNING;
+
   SETUP_LOG("setup() completed.");
 }
 

Marlin/src/MarlinCore.h

 
 void quickstop_stepper();
 
-extern bool Running;
-inline bool IsRunning() { return  Running; }
-inline bool IsStopped() { return !Running; }
+// Global State of the firmware
+enum MarlinState : uint8_t {
+  MF_INITIALIZING =  0,
+  MF_RUNNING      = _BV(0),
+  MF_PAUSED       = _BV(1),
+  MF_WAITING      = _BV(2),
+  MF_STOPPED      = _BV(3),
+  MF_KILLED       = _BV(7)
+};
+
+extern MarlinState marlin_state;
+inline bool IsRunning() { return marlin_state == MF_RUNNING; }
+inline bool IsStopped() { return marlin_state != MF_RUNNING; }
 
 bool printingIsActive();
 bool printingIsPaused();

Marlin/src/gcode/control/M999.cpp

 #include "../gcode.h"
 
 #include "../../lcd/ultralcd.h" // for lcd_reset_alert_level
-#include "../../MarlinCore.h"   // for Running
+#include "../../MarlinCore.h"   // for marlin_state
 #include "../queue.h"           // for flush_and_request_resend
 
 /**
  *
  */
 void GcodeSuite::M999() {
-  Running = true;
+  marlin_state = MF_RUNNING;
   ui.reset_alert_level();
 
   if (parser.boolval('S')) return;

Marlin/src/module/temperature.cpp

 //
 
 inline void loud_kill(PGM_P const lcd_msg, const heater_ind_t heater) {
-  Running = false;
+  marlin_state = MF_KILLED;
   #if USE_BEEPER
     for (uint8_t i = 20; i--;) {
       WRITE(BEEPER_PIN, HIGH); delay(25);
 
     /**
       SERIAL_ECHO_START();
-      SERIAL_ECHOPGM("Thermal Thermal Runaway Running. Heater ID: ");
+      SERIAL_ECHOPGM("Thermal Runaway Running. Heater ID: ");
       if (heater_id == H_CHAMBER) SERIAL_ECHOPGM("chamber");
       if (heater_id < 0) SERIAL_ECHOPGM("bed"); else SERIAL_ECHO(heater_id);
       SERIAL_ECHOPAIR(" ;  State:", sm.state, " ;  Timer:", sm.timer, " ;  Temperature:", current, " ;  Target Temp:", target);