timeout when waiting for mmu OK

Firmware/Marlin.h

@@ -464,4 +464,6 @@ void gcode_M701();
 
 #define UVLO !(PINE & (1<<4))
 
-void proc_commands();
+void proc_commands();
+
+bool mmu_get_reponse();

Firmware/Marlin_main.cpp

@@ -3364,7 +3364,12 @@ void process_commands()
 		}
 		else if (code_seen("thx")) {
 			no_response = false;
-		}		
+		}	
+		else if (code_seen("MMURES")) {
+			fprintf_P(uart2io, PSTR("x0"));
+			bool response = mmu_get_reponse();
+			if (!response) printf_P(PSTR("MMU not responding"));
+		}
 		else if (code_seen("RESET")) {
             // careful!
             if (farm_mode) {
@@ -7119,18 +7124,7 @@ Sigma_Exit:
               fprintf_P(uart2io, PSTR("T0\n"));
               break;
           }
-
-          
-
-          
-              // get response
-            uart2_rx_clr();
-              while (!uart2_rx_ok())
-              {
-                  //printf_P(PSTR("waiting..\n"));
-                  delay_keep_alive(100);
-              }
-			  snmm_extruder = tmp_extruder; //filament change is finished
+    	  snmm_extruder = tmp_extruder; //filament change is finished
 
 		  if (*(strchr_pointer + index) == '?') { // for single material usage with mmu
 			  bool saved_e_relative_mode = axis_relative_modes[E_AXIS];
@@ -9137,4 +9131,21 @@ static void print_time_remaining_init() {
 	print_percent_done_silent = PRINT_PERCENT_DONE_INIT;
 }
 
+bool mmu_get_reponse() {
+	bool response = true;
+	LongTimer mmu_get_reponse_timeout;
+    uart2_rx_clr();
+	
+	mmu_get_reponse_timeout.start();
+	while (!uart2_rx_ok())
+    {
+      delay_keep_alive(100);
+	  if (mmu_get_reponse_timeout.expired(30 * 1000ul)) { //PINDA cooling from 60 C to 35 C takes about 7 minutes
+			response = false;
+			break;
+	  }
+    }
+	return response;
+}
+
 #define FIL_LOAD_LENGTH 60

Firmware/ultralcd.cpp

@@ -3070,7 +3070,7 @@ bool lcd_wait_for_pinda(float temp) {
 	}
 	lcd_set_custom_characters_arrows();
 	lcd_update_enable(true);
-	return(target_temp_reached);
+	return target_temp_reached;
 }
 
 void lcd_wait_for_heater() {