Display Filament Sensor data on 20x4 LCD

Changes to support displaying the real-time filament width and the
volume factor on a 20x4 LCD.  The data is displayed on the 4th line.
First the status message is displayed for 5 seconds, and then the
filament data is displayed.  The status message can be seen by
re-selecting the info screen in the menu.

Marlin/Configuration.h

@@ -773,7 +773,7 @@ const bool Z_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of
  * 
  * Motherboards
  * 34 - RAMPS1.4 - uses Analog input 5 on the AUX2 connector 
- * 81 - Printrboard - Uses Analog input 2 on the Aux 2 connector
+ * 81 - Printrboard - Uses Analog input 2 on the Exp1 connector (version B,C,D,E)
  * 301 - Rambo  - uses Analog input 3
  * Note may require analog pins to be defined for different motherboards
  **********************************************************************/
@@ -789,6 +789,8 @@ const bool Z_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of
 //defines used in the code
 #define DEFAULT_MEASURED_FILAMENT_DIA  DEFAULT_NOMINAL_FILAMENT_DIA  //set measured to nominal initially 
 
+//When using an LCD, uncomment the line below to display the Filament sensor data on the last line instead of status.  Status will appear for 5 sec.
+//#define FILAMENT_LCD_DISPLAY
 
 
 

Marlin/ultralcd.cpp

@@ -20,6 +20,12 @@ int absPreheatHPBTemp;
 int absPreheatFanSpeed;
 
 
+#ifdef FILAMENT_LCD_DISPLAY
+unsigned long message_millis=0;
+#endif
+
+
+
 #ifdef ULTIPANEL
 static float manual_feedrate[] = MANUAL_FEEDRATE;
 #endif // ULTIPANEL
@@ -195,6 +201,9 @@ static void lcd_status_screen()
         encoderPosition = 0;
         lcd_quick_feedback();
         lcd_implementation_init(); // to maybe revive the LCD if static electricity killed it.
+#ifdef FILAMENT_LCD_DISPLAY
+        message_millis=millis();  //get status message to show up for a while
+#endif
     }
 
 #ifdef ULTIPANEL_FEEDMULTIPLY
@@ -1321,6 +1330,9 @@ void lcd_setstatus(const char* message)
         return;
     strncpy(lcd_status_message, message, LCD_WIDTH);
     lcdDrawUpdate = 2;
+#ifdef FILAMENT_LCD_DISPLAY
+        message_millis=millis();  //get status message to show up for a while
+#endif
 }
 void lcd_setstatuspgm(const char* message)
 {
@@ -1328,6 +1340,9 @@ void lcd_setstatuspgm(const char* message)
         return;
     strncpy_P(lcd_status_message, message, LCD_WIDTH);
     lcdDrawUpdate = 2;
+#ifdef FILAMENT_LCD_DISPLAY
+        message_millis=millis();  //get status message to show up for a while
+#endif
 }
 void lcd_setalertstatuspgm(const char* message)
 {
@@ -1515,6 +1530,20 @@ char *ftostr32(const float &x)
   return conv;
 }
 
+//Float to string with 1.23 format
+char *ftostr12ns(const float &x)
+{
+  long xx=x*100;
+  
+  xx=abs(xx);
+  conv[0]=(xx/100)%10+'0';
+  conv[1]='.';
+  conv[2]=(xx/10)%10+'0';
+  conv[3]=(xx)%10+'0';
+  conv[4]=0;
+  return conv;
+}
+
 char *itostr31(const int &xx)
 {
   conv[0]=(xx>=0)?'+':'-';

Marlin/ultralcd.h

@@ -45,6 +45,10 @@
   
   extern bool cancel_heatup;
   
+  #ifdef FILAMENT_LCD_DISPLAY
+        extern unsigned long message_millis;
+  #endif
+    
   void lcd_buzz(long duration,uint16_t freq);
   bool lcd_clicked();
 
@@ -109,6 +113,7 @@ char *ftostr3(const float &x);
 char *ftostr31ns(const float &x); // float to string without sign character
 char *ftostr31(const float &x);
 char *ftostr32(const float &x);
+char *ftostr12ns(const float &x); 
 char *ftostr5(const float &x);
 char *ftostr51(const float &x);
 char *ftostr52(const float &x);

Marlin/ultralcd_implementation_hitachi_HD44780.h

@@ -499,9 +499,23 @@ static void lcd_implementation_status_screen()
     }
 #endif
 
-    //Status message line on the last line
+    //Display both Status message line and Filament display on the last line
+    #ifdef FILAMENT_LCD_DISPLAY
+      if(message_millis+5000>millis()){  //display any status for the first 5 sec after screen is initiated
+         	 lcd.setCursor(0, LCD_HEIGHT - 1);
+        	 lcd.print(lcd_status_message);
+        } else {
+		     lcd.setCursor(0,LCD_HEIGHT - 1);
+		     lcd_printPGM(PSTR("Dia "));
+		     lcd.print(ftostr12ns(filament_width_meas));
+		     lcd_printPGM(PSTR(" V"));
+		     lcd.print(itostr3(100.0*volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM]));
+    		 lcd.print('%');
+        }
+    #else
     lcd.setCursor(0, LCD_HEIGHT - 1);
     lcd.print(lcd_status_message);
+    #endif
 }
 static void lcd_implementation_drawmenu_generic(uint8_t row, const char* pstr, char pre_char, char post_char)
 {