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This firmware is intended to be a fully object-oriented highly modular control program for
RepRap self-replicating 3D printers.

It owes a lot to Marlin and to the original RepRap FiveD_GCode.

This is the version for the RepRap Duet:  

To edit and compile this you will also need the libraries in this repository:

A complete uploadable executable version is in the directory Release/RepRapFirmware.bin in this
repository.  For details of how to flash it to a Duet see here:

For details of how to compile the source code, see below.

General design principles:

  * Control by RepRap G Codes.  These are taken to be machine independent, though some may be unsupported.
  * Full use of C++ OO techniques,
  * Make classes hide their data,
  * Make everything except the Platform class (see below) as stateless as possible,
  * No use of conditional compilation except for #include guards - if you need that, you should be
       forking the repository to make a new branch - let the repository take the strain,
  * Concentration of all machine-dependent definitions and code in Platform.h and Platform.cpp,
  * No specials for (X,Y) or (Z) - all movement is 3-dimensional,
  * Except in Platform.h, use real units (mm, seconds etc) throughout the rest of the code wherever possible,
  * Try to be efficient in memory use, but this is not critical,
  * Labour hard to be efficient in time use, and this is critical,
  * Don't abhor floats - they work fast enough if you're clever,
  * Don't avoid arrays and structs/classes,
  * Don't avoid pointers,
  * Use operator and function overloading where appropriate.

Naming conventions:

  * No underscores in other names - MakeReadableWithCapitalisation
  * Class names and functions start with a CapitalLetter
  * Variables start with a lowerCaseLetter
  * Use veryLongDescriptiveNames


There are eight main classes:

  * RepRap
  * GCodes
  * Heat
  * Move
  * Platform
  * Network
  * Webserver, and
  * PrintMonitor


This is just a container class for the single instances of all the others, and otherwise does very little.


This class is fed GCodes, either from the web interface, or from GCode files, or from a serial interface,
Interprets them, and requests actions from the RepRap machine via the other classes.


This class implements all heating and temperature control in the RepRap machine.


This class controls all movement of the RepRap machine, both along its axes, and in its extruder drives.


This is the only class that knows anything about the physical setup of the RepRap machine and its
controlling electronics.  It implements the interface between all the other classes and the RepRap machine.
All the other classes are completely machine-independent (though they may declare arrays dimensioned
to values #defined in Platform.h).


This class implements a basic TCP interface for the Webserver classes using LWIP.


This class talks to the network (via Platform) and implements a simple webserver to give an interactive
interface to the RepRap machine. It uses the Knockout and Jquery Javascript libraries to achieve this.
In addition, FTP and Telnet servers are provided for easier SD card file management and G-Code handling.


This class provides methods to obtain statistics (height, filament usage etc.) from generated G-Code
files and to calculate estimated print end-times for a live print.

When the software is running there is one single instance of each main class, and all the memory allocation is
done on initialization.  new/malloc should not be used in the general running code, and delete is never
used.  Each class has an Init() function that resets it to its boot-up state; the constructors merely handle
that memory allocation on startup.  Calling RepRap.Init() calls all the other Init()s in the right sequence.

There are other ancillary classes that are declared in the .h files for the master classes that use them.  For
example, Move has a DDA class that implements a Bresenham/digital differential analyser.


There is a single interrupt chain entered via Platform.Interrupt().  This controls movement step timing, and
this chain of code should be the only place that volatile declarations and structure/variable-locking are
required.  All the rest of the code is called sequentially and repeatedly as follows:

As of version 057r-dc42 the tick interrupt (which is set up by the Arduino core) is also used to set up ADC conversions,
read the result of the last conversion, and shut down heaters when temperature errors are detected.

All the main classes have a Spin() function.  These are called in a loop by the RepRap.Spin() function and implement
simple timesharing.  No class does, or ever should, wait inside one of its functions for anything to happen or call
any sort of delay() function.  The general rule is:

  Can I do a thing?
    Yes - do it
    No - set a flag/timer to remind me to do it next-time-I'm-called/at-a-future-time and return.

The restriction this strategy places on almost all the code in the firmware (that it must execute quickly and
never cause waits or delays) is balanced by the fact that none of that code needs to worry about synchronization,
locking, or other areas of code accessing items upon which it is working.  As mentioned, only the interrupt
chain needs to concern itself with such problems.  Unlike movement, heating (including PID controllers) does
not need the fast precision of timing that interrupts alone can offer.  Indeed, most heating code only needs
to execute a couple of times a second.

Most data is transferred bytewise, with classes' Spin() functions typically containing code like this:

  Is a byte available for me?
      read it and add it to my buffer
      Is my buffer complete?
           Act on the contents of my buffer

Note that it is simple to raise the "priority" of any class's activities relative to the others by calling its
Spin() function more than once from RepRap.Spin().


Compiling from Source

RepRap Firmware was developed using the Eclipse IDE, which is much more powerful for big software projects than the Arduino IDE.

We use Eclipse Juno, which is available here:

You will also need the Eclipse Arduino support:

And the Arduino IDE itself (make sure you get the one for the Due/Duet - version 1.5.5 at the time of writing):

As of this firmware version 0.57r-dc42, the Arduino IDE must be patched to enable watchdog support. Locate function init()
inside file variant.cpp (....\hardware\arduino\sam\variants\arduino_due_x) and comment out the call to WDT_disable(WDT).
If you don't do this, the firmware will still work but you won't get the benefit of watchdog protection.

Finally you will need our libraries for driving the peripherals:

Start by getting the Arduino IDE programming your Duet with a simple Hello World program that prints to the USB (SerialUSB.print("Hello World"); on the Due/Duet, not Serial.print("Hello World");... )

Then install Eclipse and the Arduino plugin.

Make temporary copies of RepRapFirmware.cpp and RepRapFirmware.h from your download in another folder (you will only need to do this once).

Finally use Eclipse to open the Arduino project called RepRapFirmware in the folder where you have downloaded the RepRap Firmware code.  Tell Eclipse to use the Arduino-libraries files you downloaded as the local libraries.  Eclipse will complain that the project already exists (which it does - it is your download).  Ignore this and it will open the project anyway.  

Annoyingly the first time it may also overwrite RepRapFirmware.cpp and RepRapFirmware.h.  So close the project, overwrite its overwrites with the two files you saved, open the project again and refresh it.  Everything should now be ship-shape.  Add the libraries 


to your project.  Under no circumstances be tempted to add standard Arduino libraries for devices like Ethernet - these are for the Due, and will not work on the Duet.

You should now be able to compile the code and upload the result to the Duet.

Note on dc42 fork of this firmware:

As well as containing various bug fixes and performance improvements, I have added various functionality compared to the original RepRapPro version.
The major changes are:

- Z probe reading is included in the web server poll response
- Homed status (i.e. whether homes since reset) is maintained for all 3 axes and included in the web server poll response
- Once the X and Y axes have been homed, movement is limited to the range of the axis, except when the G0 or G1 command includes
  the check endstops (S1) parameter. Use the M208 command to set axis travel if the default values in the firmware are incorrect for your machine.
- Implemented M301 (hot end PID parameters) and M304 (bed PID parameters) commands. Extended these commands to allow setting of thermistor
  resistance at 25C (R parameter) and thermistor beta (B parameter). A negative P parameter means don't use PID, use bang-bang control.
- Implemented M999. This resets the Duet.
- Added temperature (T) and temperature coefficient of height (C) parameters to the G31 command
- Added support for modulated IR sensor (M558 P2) and ultrasonic sensor (M558 P3)
- Various parameters are now saved to flash memory (Z-probe parameters, network parameters, PID parameters)
- FAN0 line is driven at 25kHz and pin 25 on the expansion header (Duet) can utilise the tacho line of 4-pin PWM fans

Note on zpl fork of this firmware:

Based on dc42's long-time proven Duet firmware fork, I have implemented a couple more features and (partially) merged in features from RepRapPro's development firmware branch.
The most significant changes are:

- FTP and Telnet support
- Reliable low-level networking and implementation of the internal EMAC ISR
- Internal G-Code queuing to execute non-movement codes just-in-time and not ~20 moves too early (due to the look-ahead)
- M25: SD-card prints are paused as soon as the current move finishes
- M0 does no longer disable any stepper motors or heaters if the print is paused. This shall simplify print restarts (requires my web interface fork)
- Implemented cold retracts, minimum temperature is 90C
- Flash usage is optional; only one line needs to be commented out to disable it

See the "Changes in ... fork" text files for complete lists of all the changes dc42 and zpl have contributed.


Version beta

Started: 2012-11-18
This README dated: 2014-10-12

Adrian Bowyer
RepRap Professional Ltd

Licence: GPL