Add a uart RX timeout

Firmware/cmdqueue.cpp

@@ -24,8 +24,7 @@ int serial_count = 0;  //index of character read from serial line
 bool comment_mode = false;
 char *strchr_pointer; // just a pointer to find chars in the command string like X, Y, Z, E, etc
 
-unsigned long TimeSent = _millis();
-unsigned long TimeNow = _millis();
+ShortTimer serialTimeoutTimer;
 
 long gcode_N = 0;
 long gcode_LastN = 0;
@@ -400,8 +399,7 @@ void get_command()
         MYSERIAL.write(serial_char); // for debuging serial line 2 in farm_mode
         selectedSerialPort = 1; 
     } */ //RP - removed
-      TimeSent = _millis();
-      TimeNow = _millis();
+      serialTimeoutTimer.start();
 
     if (serial_char < 0)
         // Ignore extended ASCII characters. These characters have no meaning in the G-code apart from the file names
@@ -535,23 +533,12 @@ void get_command()
     }
   } // end of serial line processing loop
 
-    if(farm_mode){
-        TimeNow = _millis();
-        if ( ((TimeNow - TimeSent) > 800) && (serial_count > 0) ) {
-            cmdbuffer[bufindw+serial_count+CMDHDRSIZE] = 0;
-            
-            bufindw += strlen(cmdbuffer+bufindw+CMDHDRSIZE) + (1 + CMDHDRSIZE);
-            if (bufindw == sizeof(cmdbuffer))
-                bufindw = 0;
-            ++ buflen;
-            
+    if (serial_count > 0 && serialTimeoutTimer.expired(farm_mode ? 800 : 2000)) {
+        comment_mode = false;
         serial_count = 0;
-            
-            SERIAL_ECHOPGM("TIMEOUT:");
-            //memset(cmdbuffer, 0 , sizeof(cmdbuffer));
+        SERIAL_ECHOLNPGM("RX timeout");
         return;
     }
-    }
 
   #ifdef SDSUPPORT
   if(!card.sdprinting || serial_count!=0){

Firmware/cmdqueue.h

@@ -52,9 +52,6 @@ extern int serial_count;
 extern bool comment_mode;
 extern char *strchr_pointer;
 
-extern unsigned long TimeSent;
-extern unsigned long TimeNow;
-
 extern long gcode_N;
 extern long gcode_LastN;
 extern long Stopped_gcode_LastN;