overworked readme

README.md

@@ -8,8 +8,9 @@ This RepRap firmware is a mashup between <a href="https://github.com/kliment/Spr
 Derived from Sprinter and Grbl by Erik van der Zalm.
 Sprinters lead developers are Kliment and caru.
 Grbls lead developer is Simen Svale Skogsrud.
-Some features have been added by and configuration has been added by:
+A fork by bkubicek for the Ultimaker was merged, and further development was aided by him.
-Bernhard Kubicek, Matthijs Keuper, Bradley Feldman, and others...
+Some features have been added by:
+Lampmaker, Bradley Feldman, and others...
 
 
 Features:
@@ -20,33 +21,140 @@ Features:
  - preliminary support for Matthew Roberts advance algorithm 
    For more info see: http://reprap.org/pipermail/reprap-dev/2011-May/003323.html
  - Full endstop support
- - Simple LCD support (16x2)
  - SD Card support
- - Provisions for Bernhard Kubicek's new hardware control console and 20x4 lcd
+ - SD Card folders (works in pronterface)
+ - 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.
 
 This firmware is optimized for Ultimaker's gen6 electronics (including the Ultimaker 1.5.x daughterboard and Arduino Mega 2560).
 
-The default baudrate is 115200. 
+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: 
+Splic3r 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".
+
+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:
+
+G2  - CW ARC
+G3  - CCW ARC
+
+General:
+M17  - Enable/Power all stepper motors
+M18  - Disable all stepper motors; same as M84
+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
+M220 - set build speed factor override percentage S:factor in percent ; aka "realtime tuneing in the gcode"
+M301 - Set PID parameters P I and D
+M400 - Finish all moves
+
+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
+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.
+========================================================================================
+
+
 
 Configuring and compilation
 
 
-Install the latest arduino software IDE/toolset (currently 0022)
+Install the arduino software IDE/toolset v22
    http://www.arduino.cc/en/Main/Software
 
 Install Ultimaker's RepG 25 build
     http://software.ultimaker.com
-(or alternatively install Kliment's printrun/pronterface  https://github.com/kliment/Printrun_)
+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/bkubicek/Marlin
+   https://github.com/ErikZalm/Marlin/tree/Marlin_v1
    (Use the download button)
 
 Start the arduino IDE.
-Select Tools -> Board -> Arduino Mega 2560 
+Select Tools -> Board -> Arduino Mega 2560    or your microcontroller
 Select the correct serial port in Tools ->Serial Port
 Open Marlin.pde