diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index 7fc95b9979..a65c69dee2 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -71,6 +71,16 @@
 // before setting a PWM value. (Does not work with software PWM for fan on Sanguinololu)
 //#define FAN_KICKSTART_TIME 100
 
+// Configure fan pin outputs to automatically turn on/off when the associated
+// extruder temperature is above/below EXTRUDER_AUTO_FAN_TEMPERATURE.
+// Multiple extruders can be assigned to the same pin in which case 
+// the fan will turn on when any selected extruder is above the threshold.
+#define EXTRUDER_0_AUTO_FAN_PIN   -1
+#define EXTRUDER_1_AUTO_FAN_PIN   -1
+#define EXTRUDER_2_AUTO_FAN_PIN   -1
+#define EXTRUDER_AUTO_FAN_TEMPERATURE 50
+#define EXTRUDER_AUTO_FAN_SPEED   255  // == full speed
+
 //===========================================================================
 //=============================Mechanical Settings===========================
 //===========================================================================
@@ -210,9 +220,9 @@
 //  However, THIS FEATURE IS UNSAFE!, as it will only work if interrupts are disabled. And the code could hang in an interrupt routine with interrupts disabled.
 //#define WATCHDOG_RESET_MANUAL
 #endif
-
-// Enable the option to stop SD printing when hitting and endstops, needs to be enabled from the LCD menu when this option is enabled.
-//#define ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED
+
+// Enable the option to stop SD printing when hitting and endstops, needs to be enabled from the LCD menu when this option is enabled.
+//#define ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED
 
 // extruder advance constant (s2/mm3)
 //
@@ -276,7 +286,7 @@ const unsigned int dropsegments=5; //everything with less than this number of st
 #else
   #define BLOCK_BUFFER_SIZE 16 // maximize block buffer
 #endif
-
+
 
 //The ASCII buffer for recieving from the serial:
 #define MAX_CMD_SIZE 96
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 3725546171..80172c2b13 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -157,12 +157,12 @@ float add_homeing[3]={0,0,0};
 float min_pos[3] = { X_MIN_POS, Y_MIN_POS, Z_MIN_POS };
 float max_pos[3] = { X_MAX_POS, Y_MAX_POS, Z_MAX_POS };
 // Extruder offset, only in XY plane
-#if EXTRUDERS > 1
+#if EXTRUDERS > 1
 float extruder_offset[2][EXTRUDERS] = { 
 #if defined(EXTRUDER_OFFSET_X) && defined(EXTRUDER_OFFSET_Y)
   EXTRUDER_OFFSET_X, EXTRUDER_OFFSET_Y 
 #endif
-}; 
+}; 
 #endif
 uint8_t active_extruder = 0;
 int fanSpeed=0;
@@ -982,6 +982,10 @@ void process_commands()
             break;
           }
         }
+      #if FAN_PIN > -1
+        if (pin_number == FAN_PIN)
+          fanSpeed = pin_status;
+      #endif
         if (pin_number > -1)
         {
           pinMode(pin_number, OUTPUT);
@@ -1380,7 +1384,7 @@ void process_commands()
       }
       
     }break;
-    #endif // FWRETRACT
+    #endif // FWRETRACT
     #if EXTRUDERS > 1
     case 218: // M218 - set hotend offset (in mm), T<extruder_number> X<offset_on_X> Y<offset_on_Y>
     {
@@ -1405,7 +1409,7 @@ void process_commands()
          SERIAL_ECHO(extruder_offset[Y_AXIS][tmp_extruder]);
       }
       SERIAL_ECHOLN("");
-    }break;
+    }break;
     #endif
     case 220: // M220 S<factor in percent>- set speed factor override percentage
     {
@@ -1756,7 +1760,7 @@ void process_commands()
         if(make_move && Stopped == false) {
            prepare_move();
         }
-      }
+      }
       #endif
       SERIAL_ECHO_START;
       SERIAL_ECHO(MSG_ACTIVE_EXTRUDER);
diff --git a/Marlin/temperature.cpp b/Marlin/temperature.cpp
index 6093c99346..75012cff06 100644
--- a/Marlin/temperature.cpp
+++ b/Marlin/temperature.cpp
@@ -99,8 +99,9 @@ static volatile bool temp_meas_ready = false;
 #ifdef FAN_SOFT_PWM
   static unsigned char soft_pwm_fan;
 #endif
-
-
+#if EXTRUDER_0_AUTO_FAN_PIN > -1 || EXTRUDER_1_AUTO_FAN_PIN > -1 || EXTRUDER_2_AUTO_FAN_PIN > -1
+  static uint8_t extruderAutoFanState = 0; // extruder auto fan state stored as bitmap
+#endif  
   
 #if EXTRUDERS > 3
 # error Unsupported number of extruders
@@ -399,6 +400,55 @@ void manage_heater()
 
   } // End extruder for loop
   
+  #if EXTRUDER_0_AUTO_FAN_PIN > -1
+    // check the extruder 0 setting (and any ganged auto fan outputs)
+    bool newFanState = (EXTRUDER_0_AUTO_FAN_PIN > -1 && 
+        (current_temperature[0] > EXTRUDER_AUTO_FAN_TEMPERATURE || 
+            (EXTRUDER_0_AUTO_FAN_PIN == EXTRUDER_1_AUTO_FAN_PIN && current_temperature[1] > EXTRUDER_AUTO_FAN_TEMPERATURE) || 
+            (EXTRUDER_0_AUTO_FAN_PIN == EXTRUDER_2_AUTO_FAN_PIN && current_temperature[2] > EXTRUDER_AUTO_FAN_TEMPERATURE)));
+    if ((extruderAutoFanState & 1) != newFanState) // store state in first bit
+    {
+        int newFanSpeed = (newFanState ? EXTRUDER_AUTO_FAN_SPEED : 0);
+        if (EXTRUDER_0_AUTO_FAN_PIN == FAN_PIN) 
+            fanSpeed = newFanSpeed;
+        pinMode(EXTRUDER_0_AUTO_FAN_PIN, OUTPUT);
+        digitalWrite(EXTRUDER_0_AUTO_FAN_PIN, newFanSpeed);
+        analogWrite(EXTRUDER_0_AUTO_FAN_PIN, newFanSpeed);
+        extruderAutoFanState = newFanState | (extruderAutoFanState & ~1);
+    }
+  #endif //EXTRUDER_0_AUTO_FAN_PIN > -1
+  #if EXTRUDER_1_AUTO_FAN_PIN > -1
+    // check the extruder 1 setting (except when extruder 1 is the same as 0)
+    newFanState = (EXTRUDER_1_AUTO_FAN_PIN > -1 && EXTRUDER_1_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN &&
+        (current_temperature[1] > EXTRUDER_AUTO_FAN_TEMPERATURE ||
+            (EXTRUDER_1_AUTO_FAN_PIN == EXTRUDER_2_AUTO_FAN_PIN && current_temperature[2] > EXTRUDER_AUTO_FAN_TEMPERATURE)));
+    if ((extruderAutoFanState & 2) != (newFanState<<1)) // use second bit
+    {
+        int newFanSpeed = (newFanState ? EXTRUDER_AUTO_FAN_SPEED : 0);
+        if (EXTRUDER_1_AUTO_FAN_PIN == FAN_PIN) 
+            fanSpeed = newFanSpeed;
+        pinMode(EXTRUDER_1_AUTO_FAN_PIN, OUTPUT);
+        digitalWrite(EXTRUDER_1_AUTO_FAN_PIN, newFanSpeed);
+        analogWrite(EXTRUDER_1_AUTO_FAN_PIN, newFanSpeed);
+        extruderAutoFanState = (newFanState<<1) | (extruderAutoFanState & ~2);
+    }
+  #endif //EXTRUDER_1_AUTO_FAN_PIN > -1
+  #if EXTRUDER_2_AUTO_FAN_PIN > -1
+    // check the extruder 2 setting (except when extruder 2 is the same as 1 or 0)
+    newFanState = (EXTRUDER_2_AUTO_FAN_PIN > -1 && 
+            EXTRUDER_2_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN && EXTRUDER_2_AUTO_FAN_PIN != EXTRUDER_1_AUTO_FAN_PIN &&
+        current_temperature[2] > EXTRUDER_AUTO_FAN_TEMPERATURE);
+    if ((extruderAutoFanState & 4) != (newFanState<<2)) // use third bit
+    {
+        int newFanSpeed = (newFanState ? EXTRUDER_AUTO_FAN_SPEED : 0);
+        if (EXTRUDER_2_AUTO_FAN_PIN == FAN_PIN) 
+            fanSpeed = newFanSpeed;
+        pinMode(EXTRUDER_2_AUTO_FAN_PIN, OUTPUT);
+        digitalWrite(EXTRUDER_2_AUTO_FAN_PIN, newFanSpeed);
+        analogWrite(EXTRUDER_2_AUTO_FAN_PIN, newFanSpeed);
+        extruderAutoFanState = (newFanState<<2) | (extruderAutoFanState & ~4);
+    }
+  #endif //EXTRUDER_2_AUTO_FAN_PIN > -1
 
   #ifndef PIDTEMPBED
   if(millis() - previous_millis_bed_heater < BED_CHECK_INTERVAL)
diff --git a/README.md b/README.md
index 309fdd1d1d..ada4e83820 100644
--- a/README.md
+++ b/README.md
@@ -1,223 +1,227 @@
-WARNING: 
---------
-THIS IS RELEASE CANDIDATE 2 FOR MARLIN 1.0.0
-
-The configuration is now split in two files
-Configuration.h for the normal settings
-Configuration_adv.h for the advanced settings
-
-Gen7T is not supported.
-
-Quick Information
-===================
-This RepRap firmware is a mashup between <a href="https://github.com/kliment/Sprinter">Sprinter</a>, <a href="https://github.com/simen/grbl/tree">grbl</a> and many original parts.
-
-Derived from Sprinter and Grbl by Erik van der Zalm.
-Sprinters lead developers are Kliment and caru.
-Grbls lead developer is Simen Svale Skogsrud. Sonney Jeon (Chamnit) improved some parts of grbl
-A fork by bkubicek for the Ultimaker was merged, and further development was aided by him.
-Some features have been added by:
-Lampmaker, Bradley Feldman, and others...
-
-
-Features:
-
-*   Interrupt based movement with real linear acceleration
-*   High steprate
-*   Look ahead (Keep the speed high when possible. High cornering speed)
-*   Interrupt based temperature protection
-*   preliminary support for Matthew Roberts advance algorithm 
-    For more info see: http://reprap.org/pipermail/reprap-dev/2011-May/003323.html
-*   Full endstop support
-*   SD Card support
-*   SD Card folders (works in pronterface)
-*   SD Card autostart support
-*   LCD support (ideally 20x4) 
-*   LCD menu system for autonomous SD card printing, controlled by an click-encoder. 
-*   EEPROM storage of e.g. max-velocity, max-acceleration, and similar variables
-*   many small but handy things originating from bkubicek's fork.
-*   Arc support
-*   Temperature oversampling
-*   Dynamic Temperature setpointing aka "AutoTemp"
-*   Support for QTMarlin, a very beta GUI for PID-tuning and velocity-acceleration testing. https://github.com/bkubicek/QTMarlin
-*   Endstop trigger reporting to the host software.
-*   Updated sdcardlib
-*   Heater power reporting. Useful for PID monitoring.
-*   PID tuning
-*   CoreXY kinematics (www.corexy.com/theory.html)
-*   Configurable serial port to support connection of wireless adaptors.
-
-The default baudrate is 250000. This baudrate has less jitter and hence errors than the usual 115200 baud, but is less supported by drivers and host-environments.
-
-
-Differences and additions to the already good Sprinter firmware:
-================================================================
-
-*Look-ahead:*
-
-Marlin has look-ahead. While sprinter has to break and re-accelerate at each corner, 
-lookahead will only decelerate and accelerate to a velocity, 
-so that the change in vectorial velocity magnitude is less than the xy_jerk_velocity.
-This is only possible, if some future moves are already processed, hence the name. 
-It leads to less over-deposition at corners, especially at flat angles.
-
-*Arc support:*
-
-Slic3r can find curves that, although broken into segments, were ment to describe an arc.
-Marlin is able to print those arcs. The advantage is the firmware can choose the resolution,
-and can perform the arc with nearly constant velocity, resulting in a nice finish. 
-Also, less serial communication is needed.
-
-*Temperature Oversampling:*
-
-To reduce noise and make the PID-differential term more useful, 16 ADC conversion results are averaged.
-
-*AutoTemp:*
-
-If your gcode contains a wide spread of extruder velocities, or you realtime change the building speed, the temperature should be changed accordingly.
-Usually, higher speed requires higher temperature.
-This can now be performed by the AutoTemp function
-By calling M109 S<mintemp> T<maxtemp> F<factor> you enter the autotemp mode.
-
-You can leave it by calling M109 without any F.
-If active, the maximal extruder stepper rate of all buffered moves will be calculated, and named "maxerate" [steps/sec].
-The wanted temperature then will be set to t=tempmin+factor*maxerate, while being limited between tempmin and tempmax.
-If the target temperature is set manually or by gcode to a value less then tempmin, it will be kept without change.
-Ideally, your gcode can be completely free of temperature controls, apart from a M109 S T F in the start.gcode, and a M109 S0 in the end.gcode.
-
-*EEPROM:*
-
-If you know your PID values, the acceleration and max-velocities of your unique machine, you can set them, and finally store them in the EEPROM.
-After each reboot, it will magically load them from EEPROM, independent what your Configuration.h says.
-
-*LCD Menu:*
-
-If your hardware supports it, you can build yourself a LCD-CardReader+Click+encoder combination. It will enable you to realtime tune temperatures,
-accelerations, velocities, flow rates, select and print files from the SD card, preheat, disable the steppers, and do other fancy stuff.
-One working hardware is documented here: http://www.thingiverse.com/thing:12663 
-Also, with just a 20x4 or 16x2 display, useful data is shown.
-
-*SD card folders:*
-
-If you have an SD card reader attached to your controller, also folders work now. Listing the files in pronterface will show "/path/subpath/file.g".
-You can write to file in a subfolder by specifying a similar text using small letters in the path.
-Also, backup copies of various operating systems are hidden, as well as files not ending with ".g".
-
-*SD card folders:*
-
-If you place a file auto[0-9].g into the root of the sd card, it will be automatically executed if you boot the printer. The same file will be executed by selecting "Autostart" from the menu.
-First *0 will be performed, than *1 and so on. That way, you can heat up or even print automatically without user interaction.
-
-*Endstop trigger reporting:*
-
-If an endstop is hit while moving towards the endstop, the location at which the firmware thinks that the endstop was triggered is outputed on the serial port.
-This is useful, because the user gets a warning message.
-However, also tools like QTMarlin can use this for finding acceptable combinations of velocity+acceleration.
-
-*Coding paradigm:*
-
-Not relevant from a user side, but Marlin was split into thematic junks, and has tried to partially enforced private variables.
-This is intended to make it clearer, what interacts which what, and leads to a higher level of modularization.
-We think that this is a useful prestep for porting this firmware to e.g. an ARM platform in the future.
-A lot of RAM (with enabled LCD ~2200 bytes) was saved by storing char []="some message" in Program memory.
-In the serial communication, a #define based level of abstraction was enforced, so that it is clear that
-some transfer is information (usually beginning with "echo:"), an error "error:", or just normal protocol,
-necessary for backwards compatibility.
-
-*Interrupt based temperature measurements:*
-
-An interrupt is used to manage ADC conversions, and enforce checking for critical temperatures.
-This leads to less blocking in the heater management routine.
-
-
-Non-standard M-Codes, different to an old version of sprinter:
-==============================================================
-Movement:
-
-*   G2  - CW ARC
-*   G3  - CCW ARC
-
-General:
-
-*   M17  - Enable/Power all stepper motors. Compatibility to ReplicatorG.
-*   M18  - Disable all stepper motors; same as M84.Compatibility to ReplicatorG.
-*   M30  - Print time since last M109 or SD card start to serial
-*   M42  - Change pin status via gcode
-*   M80  - Turn on Power Supply
-*   M81  - Turn off Power Supply
-*   M114 - Output current position to serial port 
-*   M119 - Output Endstop status to serial port
-
-Movement variables:
-
-*   M202 - Set max acceleration in units/s^2 for travel moves (M202 X1000 Y1000) Unused in Marlin!!
-*   M203 - Set maximum feedrate that your machine can sustain (M203 X200 Y200 Z300 E10000) in mm/sec
-*   M204 - Set default acceleration: S normal moves T filament only moves (M204 S3000 T7000) im mm/sec^2  also sets minimum segment time in ms (B20000) to prevent buffer underruns and M20 minimum feedrate
-*   M206 - set home offsets.  This sets the X,Y,Z coordinates of the endstops (and is added to the {X,Y,Z}_HOME_POS configuration options (and is also added to the coordinates, if any, provided to G82, as with earlier firmware)
-*   M220 - set build speed mulitplying S:factor in percent ; aka "realtime tuneing in the gcode". So you can slow down if you have islands in one height-range, and speed up otherwise.
-*   M221 - set the extrude multiplying S:factor in percent
-*   M400 - Finish all buffered moves.
-
-Temperature variables:
-*   M301 - Set PID parameters P I and D
-*   M302 - Allow cold extrudes
-*   M303 - PID relay autotune S<temperature> sets the target temperature. (default target temperature = 150C)
-
-Advance:
-
-*   M200 - Set filament diameter for advance
-*   M205 - advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk
-
-EEPROM:
-
-*   M500 - stores paramters in EEPROM. This parameters are stored:  axis_steps_per_unit,  max_feedrate, max_acceleration  ,acceleration,retract_acceleration,
-  minimumfeedrate,mintravelfeedrate,minsegmenttime,  jerk velocities, PID
-*   M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily).  
-*   M502 - reverts to the default "factory settings".  You still need to store them in EEPROM afterwards if you want to.
-*   M503 - print the current settings (from memory not from eeprom)
-
-MISC:
-
-*   M240 - Trigger a camera to take a photograph
-*   M999 - Restart after being stopped by error
-
-Configuring and compilation:
-============================
-
-Install the arduino software IDE/toolset v23 (Some configurations also work with 1.x.x)
-   http://www.arduino.cc/en/Main/Software
-
-For gen6/gen7 and sanguinololu the Sanguino directory in the Marlin dir needs to be copied to the arduino environment.
-  copy ArduinoAddons\Arduino_x.x.x\sanguino <arduino home>\hardware\Sanguino
-
-Install Ultimaker's RepG 25 build
-    http://software.ultimaker.com
-For SD handling and as better substitute (apart from stl manipulation) download
-the very nice Kliment's printrun/pronterface  https://github.com/kliment/Printrun
-
-Copy the Ultimaker Marlin firmware
-   https://github.com/ErikZalm/Marlin/tree/Marlin_v1
-   (Use the download button)
-
-Start the arduino IDE.
-Select Tools -> Board -> Arduino Mega 2560    or your microcontroller
-Select the correct serial port in Tools ->Serial Port
-Open Marlin.pde
-
-Click the Verify/Compile button
-
-Click the Upload button
-If all goes well the firmware is uploading
-
-Start Ultimaker's Custom RepG 25
-Make sure Show Experimental Profiles is enabled in Preferences
-Select Sprinter as the Driver
-
-Press the Connect button.
-
-KNOWN ISSUES: RepG will display:  Unknown: marlin x.y.z
-
-That's ok.  Enjoy Silky Smooth Printing.
-
-
-
+==========================
+Marlin 3D Printer Firmware
+==========================
+
+Notes: 
+-----
+
+The configuration is now split in two files:
+  Configuration.h for the normal settings
+  Configuration_adv.h for the advanced settings
+
+Gen7T is not supported.
+
+Quick Information
+===================
+This RepRap firmware is a mashup between <a href="https://github.com/kliment/Sprinter">Sprinter</a>, <a href="https://github.com/simen/grbl/tree">grbl</a> and many original parts.
+
+Derived from Sprinter and Grbl by Erik van der Zalm.
+Sprinters lead developers are Kliment and caru.
+Grbls lead developer is Simen Svale Skogsrud. Sonney Jeon (Chamnit) improved some parts of grbl
+A fork by bkubicek for the Ultimaker was merged, and further development was aided by him.
+Some features have been added by:
+Lampmaker, Bradley Feldman, and others...
+
+
+Features:
+
+*   Interrupt based movement with real linear acceleration
+*   High steprate
+*   Look ahead (Keep the speed high when possible. High cornering speed)
+*   Interrupt based temperature protection
+*   preliminary support for Matthew Roberts advance algorithm 
+    For more info see: http://reprap.org/pipermail/reprap-dev/2011-May/003323.html
+*   Full endstop support
+*   SD Card support
+*   SD Card folders (works in pronterface)
+*   SD Card autostart support
+*   LCD support (ideally 20x4) 
+*   LCD menu system for autonomous SD card printing, controlled by an click-encoder. 
+*   EEPROM storage of e.g. max-velocity, max-acceleration, and similar variables
+*   many small but handy things originating from bkubicek's fork.
+*   Arc support
+*   Temperature oversampling
+*   Dynamic Temperature setpointing aka "AutoTemp"
+*   Support for QTMarlin, a very beta GUI for PID-tuning and velocity-acceleration testing. https://github.com/bkubicek/QTMarlin
+*   Endstop trigger reporting to the host software.
+*   Updated sdcardlib
+*   Heater power reporting. Useful for PID monitoring.
+*   PID tuning
+*   CoreXY kinematics (www.corexy.com/theory.html)
+*   Configurable serial port to support connection of wireless adaptors.
+*   Automatic operation of extruder/cold-end cooling fans based on nozzle temperature
+
+The default baudrate is 250000. This baudrate has less jitter and hence errors than the usual 115200 baud, but is less supported by drivers and host-environments.
+
+
+Differences and additions to the already good Sprinter firmware:
+================================================================
+
+*Look-ahead:*
+
+Marlin has look-ahead. While sprinter has to break and re-accelerate at each corner, 
+lookahead will only decelerate and accelerate to a velocity, 
+so that the change in vectorial velocity magnitude is less than the xy_jerk_velocity.
+This is only possible, if some future moves are already processed, hence the name. 
+It leads to less over-deposition at corners, especially at flat angles.
+
+*Arc support:*
+
+Slic3r can find curves that, although broken into segments, were ment to describe an arc.
+Marlin is able to print those arcs. The advantage is the firmware can choose the resolution,
+and can perform the arc with nearly constant velocity, resulting in a nice finish. 
+Also, less serial communication is needed.
+
+*Temperature Oversampling:*
+
+To reduce noise and make the PID-differential term more useful, 16 ADC conversion results are averaged.
+
+*AutoTemp:*
+
+If your gcode contains a wide spread of extruder velocities, or you realtime change the building speed, the temperature should be changed accordingly.
+Usually, higher speed requires higher temperature.
+This can now be performed by the AutoTemp function
+By calling M109 S<mintemp> T<maxtemp> F<factor> you enter the autotemp mode.
+
+You can leave it by calling M109 without any F.
+If active, the maximal extruder stepper rate of all buffered moves will be calculated, and named "maxerate" [steps/sec].
+The wanted temperature then will be set to t=tempmin+factor*maxerate, while being limited between tempmin and tempmax.
+If the target temperature is set manually or by gcode to a value less then tempmin, it will be kept without change.
+Ideally, your gcode can be completely free of temperature controls, apart from a M109 S T F in the start.gcode, and a M109 S0 in the end.gcode.
+
+*EEPROM:*
+
+If you know your PID values, the acceleration and max-velocities of your unique machine, you can set them, and finally store them in the EEPROM.
+After each reboot, it will magically load them from EEPROM, independent what your Configuration.h says.
+
+*LCD Menu:*
+
+If your hardware supports it, you can build yourself a LCD-CardReader+Click+encoder combination. It will enable you to realtime tune temperatures,
+accelerations, velocities, flow rates, select and print files from the SD card, preheat, disable the steppers, and do other fancy stuff.
+One working hardware is documented here: http://www.thingiverse.com/thing:12663 
+Also, with just a 20x4 or 16x2 display, useful data is shown.
+
+*SD card folders:*
+
+If you have an SD card reader attached to your controller, also folders work now. Listing the files in pronterface will show "/path/subpath/file.g".
+You can write to file in a subfolder by specifying a similar text using small letters in the path.
+Also, backup copies of various operating systems are hidden, as well as files not ending with ".g".
+
+*SD card folders:*
+
+If you place a file auto[0-9].g into the root of the sd card, it will be automatically executed if you boot the printer. The same file will be executed by selecting "Autostart" from the menu.
+First *0 will be performed, than *1 and so on. That way, you can heat up or even print automatically without user interaction.
+
+*Endstop trigger reporting:*
+
+If an endstop is hit while moving towards the endstop, the location at which the firmware thinks that the endstop was triggered is outputed on the serial port.
+This is useful, because the user gets a warning message.
+However, also tools like QTMarlin can use this for finding acceptable combinations of velocity+acceleration.
+
+*Coding paradigm:*
+
+Not relevant from a user side, but Marlin was split into thematic junks, and has tried to partially enforced private variables.
+This is intended to make it clearer, what interacts which what, and leads to a higher level of modularization.
+We think that this is a useful prestep for porting this firmware to e.g. an ARM platform in the future.
+A lot of RAM (with enabled LCD ~2200 bytes) was saved by storing char []="some message" in Program memory.
+In the serial communication, a #define based level of abstraction was enforced, so that it is clear that
+some transfer is information (usually beginning with "echo:"), an error "error:", or just normal protocol,
+necessary for backwards compatibility.
+
+*Interrupt based temperature measurements:*
+
+An interrupt is used to manage ADC conversions, and enforce checking for critical temperatures.
+This leads to less blocking in the heater management routine.
+
+
+Non-standard M-Codes, different to an old version of sprinter:
+==============================================================
+Movement:
+
+*   G2  - CW ARC
+*   G3  - CCW ARC
+
+General:
+
+*   M17  - Enable/Power all stepper motors. Compatibility to ReplicatorG.
+*   M18  - Disable all stepper motors; same as M84.Compatibility to ReplicatorG.
+*   M30  - Print time since last M109 or SD card start to serial
+*   M42  - Change pin status via gcode
+*   M80  - Turn on Power Supply
+*   M81  - Turn off Power Supply
+*   M114 - Output current position to serial port 
+*   M119 - Output Endstop status to serial port
+
+Movement variables:
+
+*   M202 - Set max acceleration in units/s^2 for travel moves (M202 X1000 Y1000) Unused in Marlin!!
+*   M203 - Set maximum feedrate that your machine can sustain (M203 X200 Y200 Z300 E10000) in mm/sec
+*   M204 - Set default acceleration: S normal moves T filament only moves (M204 S3000 T7000) im mm/sec^2  also sets minimum segment time in ms (B20000) to prevent buffer underruns and M20 minimum feedrate
+*   M206 - set home offsets.  This sets the X,Y,Z coordinates of the endstops (and is added to the {X,Y,Z}_HOME_POS configuration options (and is also added to the coordinates, if any, provided to G82, as with earlier firmware)
+*   M220 - set build speed mulitplying S:factor in percent ; aka "realtime tuneing in the gcode". So you can slow down if you have islands in one height-range, and speed up otherwise.
+*   M221 - set the extrude multiplying S:factor in percent
+*   M400 - Finish all buffered moves.
+
+Temperature variables:
+*   M301 - Set PID parameters P I and D
+*   M302 - Allow cold extrudes
+*   M303 - PID relay autotune S<temperature> sets the target temperature. (default target temperature = 150C)
+
+Advance:
+
+*   M200 - Set filament diameter for advance
+*   M205 - advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk
+
+EEPROM:
+
+*   M500 - stores paramters in EEPROM. This parameters are stored:  axis_steps_per_unit,  max_feedrate, max_acceleration  ,acceleration,retract_acceleration,
+  minimumfeedrate,mintravelfeedrate,minsegmenttime,  jerk velocities, PID
+*   M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily).  
+*   M502 - reverts to the default "factory settings".  You still need to store them in EEPROM afterwards if you want to.
+*   M503 - print the current settings (from memory not from eeprom)
+
+MISC:
+
+*   M240 - Trigger a camera to take a photograph
+*   M999 - Restart after being stopped by error
+
+Configuring and compilation:
+============================
+
+Install the arduino software IDE/toolset v23 (Some configurations also work with 1.x.x)
+   http://www.arduino.cc/en/Main/Software
+
+For gen6/gen7 and sanguinololu the Sanguino directory in the Marlin dir needs to be copied to the arduino environment.
+  copy ArduinoAddons\Arduino_x.x.x\sanguino <arduino home>\hardware\Sanguino
+
+Install Ultimaker's RepG 25 build
+    http://software.ultimaker.com
+For SD handling and as better substitute (apart from stl manipulation) download
+the very nice Kliment's printrun/pronterface  https://github.com/kliment/Printrun
+
+Copy the Ultimaker Marlin firmware
+   https://github.com/ErikZalm/Marlin/tree/Marlin_v1
+   (Use the download button)
+
+Start the arduino IDE.
+Select Tools -> Board -> Arduino Mega 2560    or your microcontroller
+Select the correct serial port in Tools ->Serial Port
+Open Marlin.pde
+
+Click the Verify/Compile button
+
+Click the Upload button
+If all goes well the firmware is uploading
+
+Start Ultimaker's Custom RepG 25
+Make sure Show Experimental Profiles is enabled in Preferences
+Select Sprinter as the Driver
+
+Press the Connect button.
+
+KNOWN ISSUES: RepG will display:  Unknown: marlin x.y.z
+
+That's ok.  Enjoy Silky Smooth Printing.
+
+
+