Windows XP Build Script for Arduino

If you use an Arduino board with Windows XP...

If you like to code in C/C++ and have total control of compilation...

If you dislike GUI IDEs and prefer coding in <your favorite text editor> with a makefile...

A Windows XP Build Script is all you need!!!


Arduino (Show/Hide)

If you want to read more about Arduino, unhide this section.

I have been working on a MIDI controller project that requires sampling some electronics and then communicating with a mixer software on a PC. I have tried several other microcontroller kits like the MIT Handyboard, but so far the Arduino board is the most satisfying piece of prototyping electronics I've ever seen.

The Arduino board utilizes an ATmega168 microcontroller chip and a FTDI USB-Serial chip and turns small-scale embedded system prototyping into a fun and easy experience. It supports Serial communication through its USB port (or its RX/TX pins), provides a handful of digital and analog I/O's, and most importantly it comes in a 2in x 3in package that can easily fit into anywhere.

The package comes with the Arduino IDE that allows easy coding in a language similar to C++ (they call it the Arduino language). In fact, you are coding in C/C++ without realizing it, but the IDE provides the main() function already so you don't need to code one. The IDE is very user-friendly because all you need to do is to code your program, click the download button and the IDE will take care of the rest. This IDE is in fact ideal especially for novice users who are not familiar with embedded electronics design (or are victims of the command-line-phobia). It comes with a built in Serial communication tool as well!

The Arduino IDE and build process

The Arduino IDE seems to be tailored to smaller programs in which all codes can fit into one file. In my case, I'd like to have multiple files to keep things organized. I'd also want to have codes shared by two or more projects, so I have files in separate folders. The IDE seems to get confused by the file paths and it was not long until I found it too bothersome to get the projects to compile and link properly. I love the legendary makefile and command line tools after all.

The entire Arduino platform is actually a frontend of the WinAVR tools, which is essentially an ATmega128 extension of the GNU collection. So all I needed was to write a batch file that executes the proper commands to compile, link and download the program. Of course, this could be a difficult task, but it turned out that I wasn't the first one, as I found exactly what I wanted at the Arduino Playground.

The Windows command line build was written by Don Cross and is a build script that works seamlessly. Though, this tool comes in three batch file and was a little bit difficult to digest/customize at the first glance. Also, the tool assumes that all your code comes in one single file. These batch files weren't exactly what I wanted, but they did provide a good starting point!

THE Arduino build script

After some poking around, I wrote up a makefile-like build script. The script, along with an example project, can be downloaded here:

ArduinoBuildScript.zip

Below is a description of the build.bat build script:

1 Configs (Show/Hide)

Some environment variables are set here:

• relative path to the Arduino folder
  
• some lower level settings for downloading the program to Arduino board (If you are using an Arduino Diecimila or Arduino Duemilanove, the settings should work perfect)
  
• the COM port your Arduino is plugged into (Can be found in Device Manager under Ports(COM&LPT))
  

Then you'll need to provide the followings:

• your project name
  
• source folder and output folder
  
• a list of source file paths relative to the source folder
  
• a list of directories for compiler to search for header files
  
• any Arduino 3rd party libraries used in the project
  
• compiler options
  

Presumably these are all you need to edit for your project to compile and load. The rest of the script are the codes to compile, link, and download the program to the Arduino.

2 Parse command line option (Show/Hide)

This is a simple command line parser so that I can specify what action to take or not take when I execute the build script. The default targets are all, clean, compile and download. Adding your own options should be quite straight forward so feel free to do so when needed.

3 Prepare environment variables (Show/Hide)

Here some variables are generated. I doubt that you will need to tweak anything here...

4 Clean output files (Show/Hide)

These codes clean up the previously compiled object files and the output program files. Some error checkings were written to halt the build script in case your OS cannot delete a file (e.g. the file is somehow read-only, or you don't have access permission)

5 Compile source codes (Show/Hide)

The project source codes are first compiled and then the Arduino and 3rd party libraries. The script will select avr-gcc or avr-g++ according to the file extension supplied (.c and .cpp respectively). If you use other file types you will need to tweak the code here a bit. Also, note that warnings are turned off for Arduino and 3rd party libraries.

6 Link to elf file (Show/Hide)

After compiling, the Arduino and 3rd party library objects are first archived. Then, the project objects are linked with the archive to form the resultant elf file. This way, only needed codes from the archive are linked instead of all functions, so the program is smaller in size.

7 Download to microcontroller (Show/Hide)

The final step is to download the elf file onto the ATmega128 chip using avrdude. avrdude will first erase the flash memory, and then write the program. It will also verify the data as well. avrdude provides a progress bar so you can see the progress of this operation. When all is done, your Arduino board will automatically reset and start running. =D

The Example project and Further customization

To run the example, simply hook up your Arduino board, edit the COM port in the script and execute buildExample.bat. The example demonstrates compiling and loading a multi-file project. Note that I made it include a 3rd party library called SoftwareSerial. The project doesn't really need it but I included it to demonstrate how you can simply provide a space delimited list to tell the build script to compile and link the 3rd party libraries.

NOTE: It is important that you execute the init() function at the beginning of your main() function. The init() function initializes the hardware of the board etc. Also, remember to include the WProgram.h header file whenever you use an Arduino function call (like Serial and digitalWrite).

This build script hopefully provides a good basis of a customized makefile for everyone. My original intention was to also code other features into the script, but I decided that there are too many possible features you can add and it's down to your choice of functionality. Without modifying any codes this script supports compiling and loading multiple source files in multiple folders.

With a little modification, you can also customize this script to do the following:

• support more than 1 config with the same script (like a DEBUG preprocessor flag): You can add a command line option, then use an if statement to set the variables to respective values.
  
• support more than 1 project: Similar to above, but use a command line option and an if statement to switch between sets of source files and output name. The project outputs will locate in its own folder so you can compile multiple projects without affecting each other.
  
• save the build process console output to a file: change the BUILDLOG variable
  

... and lots of other features! Once you get familiar with the script, you should be able to tweak it according to your own need. So enjoy!