Arduino Template Express – Compiling Core Libraries

I remember spending countless hours compiling the Linux kernel back in my college days.  That experience helped me develop a taste for command line utilities and the productivity they bring to a developer workflow.  As you expand your horizons experimenting with AVR micro-controllers and Arduino boards, the time will come when you will need to compile the Arduino core libraries for a new or existing board.   The reasons could range from experimenting with a board at different frequencies to using other Atmel micro-controllers. This post covers how to add a new development board to the Arduino Template Express environment and then compile the libraries it supports.  This post is part of the Arduino Template Express (ATE) series. You may also be interested in these other posts:

  1. Arduino Template Express – Installation
  2. Arduino Template Express – Creating a Sketch
  3. Arduino Template Express – Creating a Library
  4. Arduino Template Express – Using ATTiny Micro-Controllers


In order to follow this tutorial you will need to have installed Arduino Template Express (ATE).  You will also need msbuild installed and available in your application path together with a few add-ons.   To install ATE follow the Arduino Template Express – Installation.  Atmel Studio 6.1 is based on Microsoft Visual Studio. My expectation is msbuild 4.0 is installed with Atmel Studio when it installs the dotnet framework, but I cannot verify that is the case because I had Microsoft Visual Studio already installed when I installed Atmel Studio. To check if msbuild is installed open a command window and type the following command.

reg.exe query "HKLM\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0" /v MSBuildToolsPath

If reg.exe comes back with unable to find the specified registry key or value, msbuild is not installed.  You will need to download the full Dotnet Framework 4.0 from Microsoft.  You will also need to install the msbuild community task and the msbuild extension pack.

Registering the New Board

Figure 1 contains a list of the libraries and boards supported by  Arduino Template Express (ATE).  For the purpose of this tutorial, I am going to add support for the Arduino Mega 1280 board.

List of supported libraries

Figure 1 – Supported Libraries

The task of compiling core libraries for a new board requires registration of the board in the boards.xml file and registering a reference to the new board in the project for each library you want compile.  Let’s take care of registering the Mega1280 board first.  Since the Mega2560 and the Mega1280 are very similar boards, I am going to use the entry for the Mega2560 as a model.  Follow these instructions:

  1. Locate the directory where ATE is installed.  Typically USER\Documents\Arduino Template Express.  If you are not sure open a command window and type set | find “ATE_HOME”.  It will display the environment variable ATE_HOME which points to the location where ATE is installed.
  2. Open %ATE_HOME%\boards.xml with your favorite editor.  Copy the <BoardList> entry for the Mega2560.  In the original file it begins on line 51 and ends on line 71.
  3. Paste the entry and make the changes illustrated in listing 1.   I have used the description of the board provided in the Arduino site.
    <BoardList Include="Mega1280" >
        <DataPort>COM5</DataPort> <!-- Use the port supported in your environment -->
       The Arduino Mega is a microcontroller board based on the ATmega1280 (datasheet).
       It has 54 digital input/output pins (of which 14 can be used as PWM outputs),
       16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator,
       a USB connection, a power jack, an ICSP header, and a reset button.
       It contains everything needed to support the microcontroller; simply connect it
       to a computer with a USB cable or power it with a AC-to-DC adapter or battery
       to get started. The Mega is compatible with most shields designed for the
       Arduino Duemilanove or Diecimila.

Note that for the graphic that is displayed with the board when the new project wizard is launched I have specified external.mega1280.  This tells the wizard to look in the %ATE_HOME%\Graphics for a file named external.mega1280.png.  The size of the picture must be 150×150 pixels and the format must be png.  Figure 2, illustrates the picture of the board used.  Save it to %ATE_HOME%\Graphics and make sure it is named external.mega1280.png.

Mega1280 Board Figure 2 – Mega1280 Board

Next step is to take care of the default programmer for the Mega1280.  I declare Mega1280BootLoader to be default programmer.  A development board can be configured to support multiple programmers (bootloader,ISP,custom,etc) and the desired programmer activated from the sketch project.  Search for Mega2560BootLoader.  It should be around line 471.  Copy the content from line 471 to line 480 and paste it..  Listing 2, illustrates how the programmer entry should be changed.

   <Programmer Include="Mega1280BootLoader">
        <ComPort>COM5</ComPort> <!-- Use the port supported in your environment -->

Change the ComPort entry as needed in your environment.  The Programmer entry in listing 2 uses avrdude and the wiring protocol to program the board.  You could also use an ISP programmer if you are not going to use the bootloader.  When the option to upload a sketch is pressed in Atmel Studio, this is the entry that drives how the sketch is uploaded to the development board.  We are now ready to add the Mega1280 board to the Arduino core libraries to complete the process.

Adding the New Board to Target Libraries

The first library we are going to test is the ArduinoCore library.  Open the project %ATE_HOME%\Source\ArduinoCore\ArduinoCore.atsln.  Next open the file Scripts\TagetBoards.xml.  The TargetBoards.xml contains a list of all the boards supported by the ArduinoCore library.  When compiling all supported boards from the command line, the build script loops through the list of supported boards and makes each supported board the active board, changes variables and references according to each board profile and compiles the code.  Finally the compiled code is copied to the %ATE_HOME%\Source\_Stage\BoardName\Libs\Frequency.  Follow these steps to take care of the changes.

  1. Create an entry for a new supported board and name it Mega1280 (the name must match the name used in the boards.xml).  Use the default programmer (Mega1280BootLoader)  and frequencies configure in boards.xml.
  2. Modify the CurrentBoard entry (first one in the file) to also reference the Mega1280 development board.  This step is very important.  By making the Mega1280 the CurrentBoard, the core library will only be compiled for the Mega1280 when you invoke the MakeIt.bat script with the Compile parameter.  If you skip this step, you will need to call MakeIt.bat with the CompileAll parameter which will take a while since the code will be compiled for all boards and it will get to the Mega1280 based on its position in the list.  See Figure 3 for an illustration of how the beginning of the TargetBoards.xml file should look like after the changes are done.  Do not delete the list of all the other boards supported.  We are done with the changes, let’s go ahead and compile the code.
Target Board Registry

Figure 3 – TargetBoard.xml

Compiling Arduino Core

There is a “feature” of msbuild that prevents the scripts distributed with ATE 1.0.2 Beta 3 from running when there are spaces in the path.  I have a fix that will take care of this in the final ATE 1.0.2 release.  If you have ATE 1.0.2 Beta 3, copy the folder %ATE_HOME%\Source to the root of your C:\ drive, you will end up with a c:\source folder.  If you have a folder name source already in your c:\ drive you can provide any name you want as long as it does not have a space.  Follow these instructions:

  1. Open a command window.  All prerequisites discussed at the beginning of the post need to be met for the rest of the instructions to work.
  2. Go to the directory source\ArduinoCore\Scripts and type makeit compile.  This will compile only the current board, which we previously setup to be the Mega1280.  See Figure 4 for results of compilation.

    ArduinoCore Compilation Result

    Figure 4 – Result of ArduinoCore compilation

  3. After compilation is completed, check the directory source\_stage.  You will find a Mega1280 directory with sub-directories name Headers and Libs.  The Headers contains all headers files for the ArduinoCore and future libraries you compile for this board.  The Libs contains a sub-directory for every supported frequency for the board.  In this case 16 (representing 16mhz) is the only directory available.  Inside the 16 directory you will find the ArduinoCore libraries in release and debug modes.  See Figure 5.

    stage folder

    Figure 5 – Stage folder after compilation

  4. Invoking the script makeit compileall will compile the ArduinoCore libraries for ALL boards supported.  This takes a long while and IS NOT required for this tutorial.
  5. The last step requires copying the Mega1280 folder just created to the %ATE_HOME%\Boards folder.  This is the root folders from where Atmel Studio projects pickup libraries for linking sketches.  For instance, when you develop a sketch for the Mega1280 board, libraries are expected to be found at %ATE_HOME%\Boards\Mega1280\Libs\16 and headers are located at %ATE_HOME%\Boards\Mega1280\Headers.  The frequency at the end of the libs directory changes according to the value of the F_CPU variable.
  6. To compile other libraries repeat the steps documented in the above section Adding New Board to Target Libraries.  In fact you can just copy the <CurrentBoard> and <SupportedBoard> entries created for the ArduinoCore library, see figure 3, and paste it into the targetboards.xml of the library you want to compile.  Then go to the source\LibraryIWantToComile\Scripts and run makeit.bat compile.  Look in the source\_stage\Mega1280\Libs\16 and you will find the debug and release versions of the compiled library.

Configuring a new board takes is a bit involved the first time you do it since you will need to configure tools, paths, etc. After you get the environment setup correctly and understand the mechanics of adding new boards and configuring projects to support it, adding future boards will take you a few minutes.

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Arduino Template Express – Using the ATTiny Micro-Controllers


The Arduino core libraries provide a well defined structure for developing code with the different micro-contollers it supports, but not every project requires the power provided by the ATMega 328 or 2560 chips. Simple projects can take advantage of the ATTiny family of micro-controllers. The goal of this post is to demonstrate how to use Arduino Template Express (ATE) to deploy the Arduino Core libraries to the ATTiny family of micro-controllers. This post will show you how to setup a development board with the ATTiny85 micro-controller and enable it with serial communication capabilities and the ability to use the Arduino Core libraries. In order to follow this tutorial, you will need the following:

  1. Atmel Studio 6.1 or greater
  2. Arduino Template Express (ATE) 1.0.2 or greater
  3. An ISP programmer – I will use AVRISP-MKII and AVR Dragon to demonstrate deploying code with either programmer. If you have an Arduino based ATTiny programmer, that is also fine.
  4. FTDI Breakout Board – The FTDI Basic Breakout from SparkFun or the FTDI Friend + extras from Adafruit will do the job. I will use FTDI Basic Breakout from SparkFun to allow the ATTiny85 to send serial information to a terminal. If you are creative and do not have access to a FTDI Breakout board, you can remove the ATMega328 chip from an Uno board and use the serial communication capabilities already included in the board as a substitute for the FTDI Breakout board.
  5. An ATTiny85 assembled on a breadboard or from a development board such as the one provided by Tinkerlog.

Although, I will use an ATTiny85, the instructions applies to any of the ATTiny micro-controller for which ATE provides a compiled Arduino core library. Figure 1, contains a list of supported micro-controllers.

List of supported libraries

Figure 1 – List of Supported Libraries and micro-controllers

Hardware Configuration

Let’s begin by configuring the development board. Figure 2, contains the schematic diagram of the minimum configuration needed to run an ATTiny85. This configuration uses the internal 8 MHZ clock to drive the micro-controller. In order to transfer data to the FTDI breakout board, pin 2 of the micro-controller is connected to the TX pin of the FTDI breakout board. The 5V supplied by the FTDI breakout board on pin 3 provide power to the micro-controller.  Jumper JP1 is used to enable/disable resetting the micro-controller when a terminal connection is made to the FTDI breakout board.  Jumper JP1 should be open when using the AVR Dragon to debug sketches.  If connected, the capacitor C3 causes side effects while stepping through the code.  By the way, having this jumper on the original Uno board would be a welcome feature.   Note the CTS pin of the FTDI breakout board is connected to ground to prevent the FTDI chip from stopping the transmission.

Figure 2 - ATTINY85 Breadboard Diagram

Figure 2 – ATTINY85 Breadboard Diagram

Figure 3 contains a breadboard implementation of the design. Note the usage of breadboard helpers to speed up the assembly of the circuit.

ATTiny85 Breadboard Implemenation

Figure 3 – ATTiny85 Breadboard Implementation

The FTDI breakout board comes in 5V and 3.3V flavors.  Breakout boards with more advance features have a jumper that controls the voltage output and can be switched between 3.3V and 5V.  If you happen to have a 3.3V FTDI breakout board, you will need to introduce an external power supply to drive the circuit.  Figure 4 contains a circuit diagram that uses an external power supply to provide power to the micro-controller.  Note the 3.3V pin of the FTDI breakout board is not connected to the micro-controller.

Figure 4 - ATTINY85 Breadboard diagram with dedicated power source

Figure 4 – ATTINY85 Breadboard diagram with dedicated power source

The circuits illustrated in figure 2 and 4 are functionally equivalent, the only difference is how the micro-controller is powered. It is important to note that in order for the ISP programmer to work, the micro-controller needs to be connected to an independent power source. Both, the 5V provided by the FTDI breakout board or an external power supply will satisfy this requirement.  Before proceeding connect the ISP programmer to the ISP header (J1) and configure the micro-controller fuses. Table 1 contains a list of the values of the different fuses that need to be programmed.
[table “22” not found /]

If you need information abut AVR fuses check Lady Ada tutorial on her site. Figure 5 illustrates the Atmel Studio screen from where the fuses are programmed. See (Tools/Device Programming) or (Ctrl+Shift+P).

Figure 5 - ATTINY85 Fuses as seen by Atmel Studio

Figure 5 – ATTINY85 Fuses as seen by Atmel Studio

At this point we have a development board assembled in a breadboard. The following step is to register the board in Arduino Template Express so the wizard can pick it up when new projects are created.

How ATE Supports Multiple Boards

ATE uses the concept of a development board as an abstraction of the environment for which a developer creates code. Figure 6, illustrates an entity diagram of a development board.

ATE Entity Diagram

Figure 6 – ATE Entity Diagram

Each development board has a series of properties that identify the board.  A programmer is is a logical construct that includes the port used to program the board and the application responsible for transferring the sketch created by a developer.   ATE comes configured with 17 defined boards, 8 of which can be activated during installation. An activated board shows in the list of available boards when the wizard runs to create a new project. ATE supports an unlimited number of boards that can be manually added or activated after installation. In order to enable the board ArduinoTiny85 follow the following instructions:

  1. Open the file boards.xml with your favorite editor. I would recommend Notepad++ if you do not have a favorite editor already.
  2. Find the board “ArduinoTiny85”, around line 247
  3. Change the property <EnableForProjects> to true, it is false by default. This is the flag that tells the ATE wizard to include the board as an option.
  4. Change the programmer to AVRDRAGONISP-AT.  Since I am using AVR Dragon and will use the ISP header and the atprogram.exe provided by Atmel.  If you are using another programmer, find a suitable entry or create one.  Figure 7 illustrates a modified record.
  5. Configure the DataPort field to reflect the Com Port that is created when you connect the FTDI Breakout Board.  Check the Device Manager list of Com Ports if necessary.
  6. Last, locate the programmer entry AVRDRAGONISP-AT and make sure the ComPort property is set to avrdragon and the protocol to ISP.  ATE 1.0.2 beta was shipped with the wrong port/protocol combination.  This will be changed in the final release.
Editing boards.xml

Figure 7 – Editing boards.xml

At this point we have a development board configured and registered.  Let’s proceed to create a hello world sketch.

Creating Hello World

Start by launching Atmel Studio, selecting new project, and select Arduino Sketch, see figure 8.  Once you press OK the ATE Wizard will start.


Figure 8 – New Project Dialog

 Figure 9 illustrate what the wizard will show you.  The boards will vary based on what you have installed, but the ArduinoTiny85 should be in the list.  Select ArduinoTiny85 and also select 8 Mhz from the supported speed drop down.  Press OK and a new project will be created tailored to the Attiny85.


Figure 9 – ATE Wizard with Attiny85 Board

Compile the program and you will get two errors and 4 warnings.  The errors are related to the fact the Arduino Serial library is not supported by the ATTiny85, that’s OK, let’s get rid off all Serial references and concentrate first on making the LED blink.  We’ll introduce a Serial library replacement later.  Comment all lines referencing Serial in main.cpp and Utility\buildinfo.cpp.  Do not delete the lines, just comment them.  At this point you should be able to compile the code and receive 4 warnings, but the code will compile successfully.  Make sure your board has power and the programmer is connected to the ISP header.  Press Deploy in Atmel Studio and see the LED start flashing.  If this the LED does not flash, retrace your steps to verify everything is connected properly.  It is important to note the code is Arduino friendly and you can move to any Ardunio board for which the core libraries are compiled.  This means you are capitalizing on your investment to learn and use the Arduino core library.  Now the LED is flashing and the code can be successfully deployed, let’s take care of the Serial connection.

Enabling Serial Connection

The TinyDebugSerial library provided as open source by Rowdy Dog Software is an implementation compatible with the Serial library provided by Arduino.  It only uses one pin to transmit and does not provide data receive capabilities.  Download TinyDebugSerial.cpp, TinyDebugSerial.h, TinyDebugSerial9600.cpp and core_build_options.h.  Include the “TinyDebugSerial.h” in main.cpp and “..\TinyDebugSerial.h” in BuildInfo.cpp.  Remember to remove the comments on the lines of code referencing Serial.  Recompile and deploy the code.  Open a terminal and connect to the proper COM Port and you will see output coming from the Attiny85.  If you do not want to deal with all of this, a fully functional sketch is included in the link below.  Download, compile and deploy.  If you have configured the ArduinoAttiny85 properly in your board, the deployment script will pick all your local parameters and deploy successfully.

Download Source Code: Sketch85

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Arduino Template Express – Creating a Library

In previous posts I discussed How to Install Arduino Template Express and How to Create a Sketch.  In this post let’s discuss how to create a library using Arduino Template Express and what are the advantages and disadvantages of partitioning your code into libraries.  Let’s go!

Divide and Conquer

In order to understand the benefits of libraries, let’s begin by creating the same hello world sketch we created in the How to Create a Sketch post.  Follow those instructions and come back when you have a working sketch in place. Let’s take a look at the main.cpp file to discuss what is going on in the sketch.  See Listing 1.

#ifndef SKETCH_H_
#include "Sketch.h"
/* Running counter */
static unsigned long counter = 0;
//#pragma message "Sketch Running At: " XSTR(F_CPU) " HZ"
void setup()
/* Setup pin connected to board LED for output */
pinMode(LED, OUTPUT);
/* Initialize serial interface */
/* Show build information via serial interface */
void loop()
digitalWrite(LED, HIGH);
digitalWrite(LED, LOW);
Serial.println( ++counter );

Listing 1 – Hello World Sketch

This is a monolithic sketch.  Everything it does is packed into one single development unit.  The sketch uses the Serial library and functions from the core Arduino library, but the functionality of flashing the LED and sending notifications via the UART are packaged in a single program.  As the code stands it is truly a one developer job and contains the following structural (not functional) deficiencies.

  • Unit Testing this code is very difficult.  At best you will be able to verify the LED goes on an off, but testing for LED initial conditions and controlling the timer is very difficult.
  • Having multiple developers work in this program is not possible.  Everything is packed into a single unit of work (main.cpp).
  • Reusing any code of value you develop in this sketch is not possible.  At best you will be able to use clipboard inheritance (copy and paste for the object oriented challenged).
  • Replacing the on board LED by an external LED driven from a II2C/SPI chip requires a great deal of changes because main.cpp is operating too close to the metal by invoking digitatWrite directly.

Let’s visualize how a library can help with our design by introducing a layer of abstraction.  If this was production code, I would make sure there is also a layer of abstraction for the serial communication and for the timer.  For the purpose of this example I will concentrate on the LED.  The sketch main job is manipulating the state (ON|OFF) of a pin by calling digitalWrite().  Let’s introduce the concept of a Led class with two functions on and off.  Figure 1 illustrates the class diagram of the ILed interface and possible implementations.


Figure 1

Programming to the ILed interface allows swapping different implementation transparently at compile or run time.  Instead of calling digitalWrite directly the sketch will invoke ILed.on() or to turn the LED on or off.  What are the advantages and disadvantages of introducing this level of abstraction?  I am glad you asked.  Let’s start with the advantages.

  • Programming to an interface promotes code reuse and in this case allows the design of the sketch to evolve to support an Led directly attached to the micro controller or attached to an external component with which the micro controller can communicate.  Besides SPI or II2C you could turn on and off an LED via a XBee,  WiFi, or radio interface.  The possibilities are multiple as long as you implement the ILed interface.
  • Unit Testing an ILed implementation is possible and independent of the main code.  Once an implementation is tested it can be shared and reuse in binary form with a high degree of confidence.  This promotes good design practices such as the Open/Closed principle.
  • Multiple developers can work now on this sketch.  One in the main.cpp sketch and the others in the implementation of the Led, SPILed, II2CLed classes.  The developer responsible for main.cpp will integrate to the different implementation as they become available.  The size of this sketch does not warrant such a division of labor, but in a the context of a bigger project, this option is a plus.
  • The code becomes more cohesive, a desirable trait, this benefits a few “ilities” such as maintainability, reliability, reusability, and understandability.  See Cohesion Metrics for Predicting Maintainability of Service-Oriented Software and Software Design Metrics for Predicting Maintainability of Service-Oriented Software.

Not all is good news, the introduction of ILed in the code has the following disadvantages:

  • After introducing ILed and the Led implementation, the size of the sketch is bigger.  The introduction of abstract classes (the interface of the class diagram) carries a virtual table that takes more memory than the direct digitalWrite approach.  In fact according to avr-size, the primary memory usage of the release version of the sketch goes from 3,176 bytes (9.7%) to 3,676 bytes (11.2%), while the data usage goes from 267 bytes (13%) to 296 bytes (14.5%).  This increment in size is not related to using a library, but to the introduction of ILed into the design.
  • The solution is more complex.  There are more moving parts and more code to develop in order to provide an abstraction layer for the LED.

Let’s refactor the code to introduce a library.  To add a library project to the solution, right-click on the solution and select add/project.  The new project dialog appears.  See Figure 2.  Select Arduino Library Wizard, provide the name Led and select the default location to save it.  Follow the wizard and select the same development board you previously selected for the sketch.  This will create a new library project named Led in your existing solution.


Figure 2 – Adding new library

You can download the full solution with the sketch and the library at the end of the post.  All paths for the sketch to find the library have been added using relative paths.  This is a manual step that I expected Atmel Studio to take care of when I added the library as a reference to the sketch, but unfortunately it did not happen.  See Listing 2 for the new sketch code.


/* Running counter */
static unsigned long counter = 0;

/* Micro-controller connected LED */
Led led;

Return LED as ILed to isolate caller from what
type of ILed is used
ILed* getLed()
	return &led;

 void setup()
	 /* Initialize LED */

	 /* Initialize serial interface */

	 /* Show build information via serial interface */


 void loop()
	 Serial.println( ++counter );

Listing 2 – Hello World Sketch with ILed

Line 35 and 37 take care of turning the LED on and off.  Reading the code makes it clear you are dealing with an LED.  I could have created a global ILed pointer and initialize it during setup(). The getLed() function provides an opportunity for putting logic that may switch at run time the type of LED the sketch controls.  The source code for the solution with both projects can be downloaded from here.

For Arduino developers making the transition to Atmel Studio, I hope this post has given you an introduction to how to use libraries in your projects. Coming from the Arduino IDE, an environment that promotes code reuse as source code, hides the true advantages of using libraries to decouple functional areas of an application.

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Arduino Template Express – Creating a Sketch

In this post we’ll go over creating a sketch with Arduino Template Express.  I assume you have followed the instructions of how to install ATE from my previous post.  Launch Atmel Studio and select File\New\Project or Ctrl-Shift-N.


Select Arduino Sketch Wizard, give it a proper name and location and hit OK.  The wizard will be launched with the list of development boards you have configured during installation  or after installation by modifying the boards.xml file.


I will use the Uno board for this example.  Pick an appropriate board from your setup and hit OK.  Atmel Studio will render a new project with the following layout.


This sketch flashes the on board LED and sends a running counter via the serial port.  Compile the sketch and  take a look at the output window.


The sketch is compiled and as part of the compilation the template keeps track of how many successful and failed compilations have taken place.  It also keeps track of how many successful/failed deployments occur.  Let’s deploy this puppy.  Select Tool\Deploy or press deploy in the tool bar if you have it configured.  The output window should display the outcome of the deployment.  If you launch a terminal window and connect it to your development board data port, you will see a running counter every time the LED flashes.

Additional Goodies Included Provided by ATE

  • Take a look at Utility\BuildDate.cpp.  This file gets rebuilt every time the sketch is compiled.  It generates the time stamp of the last build and you can store it in ram, EEMEM or PROGMEM.  You can optionally use this information by calling GetBuildDate().
  • Utility\BuildInfo.cpp has ShowBuildInfo() to output build information to the Serial port.
  • Utility\BuildNumber.cpp keeps track of how many successful deployments has been made.  You can optionally use this information to keep track of your deployments.

That’s all for now.  In my next post we will go over creating libraries with ATE.

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Arduino Template Express – Installation

The Arduino ecosystem consist of an IDE, development boards, development libraries and a vibrant and engaging community involved in the support and expansion of all of the components that make the ecosystem.  I acknowledge the pedagogical benefits of the Arduino IDE but if you are already used to Atmel Studio, the Arduino IDE feels like developing with training wheels.  The Arduino Template Express (ATE) enables Atmel Studio to create sketches using Arduino libraries and development boards.  AVR developers can take the best of the Arduino and continue using Atmel Studio and all the benefits it provides.  This post will walk you through the installation of ATE.

Arduino Template Express Configuration

In order to install ATE you must have already installed Atmel Studio 6.1 and Arduino 1.0.4 or higher.  Both of these programs must be installed and running successfully.  Download ATE from the Arduino Template Express site at CodePlex.  Before running setup make sure you close all instances of Atmel Studio that may be running, run atesetup.exe and agree to let the program run with administrative rights.  The following screens will guide you to the setup process.  As of the writing of this post version 1.0.2 (Beta 3) is available for download.


Press Next to get to the next screen


Press “I Agree” to accept the license and move to the next screen.


The atesetup.exe program will install pre-compiled Arduino libraries, project templates and a wizard to drive the initial configuration of sketches.  Click Next to continue.


This screen let’s you select the directories where Atmel Studio accepts new templates and the location where you want to store the application.  It is advisable to install it in your documents\Arduino Template Express folder.  The installer will try to pre-populate the directories for you.  Click Next to continue


The following screen will attempt selects the location of AVRDUDE and its configuration file also the path for atprogram.exe distributed with Atmel Studio.  Note that as of Atmel Studio 6.1 the path of atprogram.exe has changes and now it is under the atbackend directory.  The installer will try to find these programs for you, but if does not, you will need to provide their paths before continuing.  Press Next to continue.


The Board Selection screen allows you to select up to 8 boards you already own.  Do not worry, if you have more than 8 boards.  After the installation is completed you can add as many boards as you want to the boards.xml file.  In my case I have 3 development boards, an Uno, Mega2560 and Leonardo.  Note the Leonardo board requires two different ports, one for data and the other for programming.  Once you have defined all your boards, press Next to continue.


The External Tool configuration configures the option to deploy sketches from within Atmel Studio. The option is configured in the Tools menu and it is recommended that you configure the Deploy option as part of one of the tool bars in order to enable one click deployment.  Your screen may be a little different depending on the number of external tools you may have already installed in Atmel Studio.  Click Next to continue.


The About to Install screen gives you a list of what is going to be installed.  Click Install to continue and after a little while the end of the installation screen will show giving you the option to launch the readme file or go to the web site to get additional information.  I suggest you take a quick look at the readme file.


That’s all.  Hit close and the installation is completed.  If you forget where is the program installed, open a command window and type set | find “ATE_HOME” to find the path where the ATE was installed.  Next post I will walk you through the generation of a sketch that blinks the on board LED and uses the serial port.

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Arduino Programming Using Atmel Studio 6.0

This article is no longer relevant.  Please follow the Arduino Template Express update to find a more mature offering to allow development of Arduino sketches in Atmel Studio 6.1.

The Arduino IDE is a good development environment to get started with microcontrollers.  It holds your hand and hides complexities that get in a novice way.  As you gain experience and want to use advance features such as refactoring, assembly language or binary libraries, working with the Arduino IDE just doesn’t cut it.  Moving to a more advance IDE is the next logical step for a mature Arduino user.  It is the equivalent of leaving your home to go to college. Jaycon Systems has a well written three part tutorial explaining how to configure Atmel Studio 6.0 to compile Arduino projects. I have taken a different approach to solve this problem and have created an installation script to accomplish the following;

  1. Distribute a binary file for the core library (libcore).
  2. Distribute binaries of the Arduino libraries (libEEprom, libEthernet, libFirmata, libLquidCrystal, libSD, libServo, libSoftwareSerial, libSPI, libStepper, libWire).
  3. Distribute a solution with projects for all the libraries specified above so libraries can be recompile and redeployed as needed.
  4. Distribute a project template for Arduino Sketch.  This allows you to do a new project and select Arduino Sketch from the list of available templates.
  5. Distribute a project template for Arduino Lib.  This allows you to do a new project and select Arduino Library from the list of available templates.
  6. Distribute a deployment scripts to write sketches to the destination chip.  This allows a one click deployment to the Arduino board.

The rest of this post covers the configuration of the installation script and the deployment scripts in the Atmel Studio environment.

Configuring Installation Script

In order to run the installation script, you need Arduino 1.0.1 or greater and Atmel Studio 6 or greater.  Both of these programs must be installed and running successfully.  The installation script is located at the Arduino Installer site at Codeplex.  It contains all the binaries and scripts required for the installation.  Follow these instructions carefully for a successful installation.

  1. Download the installation package from Codeplex
  2. Unzip in a directory of your choice.  For the purpose of this post I am going to assume you have decompressed the installation script at c:\arduino-install.
  3. Open the file c:\arduino-install\install.bat with your favorite text editor and go to the :SetUserVariables label, around line number 31
  4. By default the ATMEL_CPU is configured to ATmega328p, change this line if necessary to reflect your microcontroller.  Typical values are ATmega32u4 (Leonardo),  ATMega328p (Uno), ATmega2560 (Mega), ATmega168 (Diecimila).
  5. The CPU_FREQUENCY and ARDUINO_VERSION do not need to be changed.  I have tested with the  Arduino 1.0.1 IDE successfully with these default values CPU_FREQUENCY=16000000 and ARDUINO_VERSION=100
  6. Set the COM_PORT variable to the communication port you are using to communicate with the Arduino board.  The default is COM3.
  7. Set the COM_PORT_SPEED variable to the proper value if necessary.  The default is 115200.
  8. The VARIANT variable refers to the pin layout of the board.  Change it accordingly to reflect the type of board you have.  The values are standard (Uno, Diecimila), leonardo (Leonardo), etc.  The default value is standard.
  9. Last setup the AVRDUDE_ROOT_DIR variable with the value of the root director where the avrdude is located.  This could be done from the Arduino installation or from Winavr.  Note that the avrdude.exe would be at AVRDUDE_ROOT_DIR\bin\avrdude.exe from the path you specify.
  10. Save the file and open a command window.  Go to the directory c:\arduino-install and run install.bat.

After a few seconds you should see an output similar to that illustrated on Figure 1.  The installation script has done the following;

Installation Results

Figure 1 – Installation Results

  1. Create directory structures at C:\users\YOUR_USER_NAME\Documents\Atmel Studio\Libs and Headers.
  2. Under Libs there are three directories, ArduinoCore for the core library, Arduino for all the Arduino libraries and Public for your personal libraries.
  3. Under Headers there are three directories, ArduinoCore for the core library headers, Arduino for the different Arduino library headers and Public for your personal library headers.
  4. All binaries and header files have been deployed to these directories.
  5. There is a file named deploy.bat located at c:\users\YOUR_USER_NAME\Documents\Atmel Studio.  This file is responsible for performing generic solution and project name clean up and then invoking the localdeploy.bat file that is located in the Arduino project directory and is part of the sketch template.
  6. In the c:\users\YOUR_USER_NAME\Documents\Atmel Studio\Templates\ProjectTemplates there are two files.  Arduino and Arduino, these are the library and sketch templates for Atmel Studio.
  7. At c:\users\YOUR_USER_NAME\Documents\Atmel Studio\ArduinoLibrariesSource a solution named ArduinoLibraries.atsln has been deployed with the source code for all the Arduino libraries so you can recompile them from within Atmel Studio if you wish to update the distributed binary libraries.

Configuring Deployment Script

The configuration of the deployment script allows you to do deployment of Arduino sketches with one click or keyboard shortcut.  Sketches are deployed to the Arduino board while libraries are deployed to the Public folder of the library directory created by the installation script.  Follow these instructions to configure the deployment script in Atmel Studio;

  1. Open the External Tool manager from Tools/External Tools
  2. Setup a new entry named &Deploy with the characteristics illustrates in Figure 2.

    Deploy Tool Definition

    Figure 2 – External Tool Definition

  3. The & before the D, makes it a hot key while in the context of the Tools menu.  This means pressing ALT-T followed by D will launch the Deploy script.
  4. The parameters must be $(SolutionDir) $(ProjectDir) $(ProjectFileName).  There is a space between each parameter.
  5. Select use Output window so you can see the outcome of the deployment within Atmel Studio.
  6. The top most entry is External Tool 1, the second one is External Tool 2 and so on.  Moving the entries up or down changes the External Tool to the command located at the target position.  If you have multiple external commands registered, keep track of the position where Deploy is located because we are going to need it later.

Let’s create a custom toolbar and add some commands that will facilitate the development experience.

  1. Go to view\Toolbar\Customize and create a new toolbar.
  2. Name the toolbar Productivity.  Hit OK and make sure the checkbox is selected.

    Productivity Toolbar

    Figure 3 – Creating a Productivity toolbar

  3. Select the Commands tab and select the Toolbar radio button.
  4. In the drop down select the Productivity toolbar we just created.
  5. Add the command Build\Build Solution
  6. Add the command Tools\External Command1 (or whatever the name of the Deploy command is in your setup)
  7. Move it up and down as needed.

    Toolbar Commands

    Figure 4 – Toolbar Commands

  8. Click on the Keyboard button and select the Tools.ExternalCommand1
  9. Enter a shortcut for it and press Assign.  In my case I configured the Tools.ExternalCommand1, which is the Deploy script as CTRL+SHIFT+P

    External Tools Shortcut

    Figure 5 – External Tools Shortcut

  10. Hit OK and we are done.  You should see a toolbar with the following information.

    Deploy Toolbar

    Figure 6 – Productivity Toolbar

The option to deploy is available via a click on the Deploy button in the Productivity toolbar or via CTRL+T followed by D or via CTRL+SHIFT+P.  Any one of these three options should satisfy your workflow.

Creating Arduino Sketches

To create your first Arduino sketch in Atmel Studio 6, launch Atmel Studio, select File\New\Project.  The new project window appears similar to figure 7 with all the installed templates.

Atmel Studio New Project

Figure 7- Atmel Studio With Arduino Templates

Select Arduino Sketch, change the name to TestSketch1, change the location if necessary and press OK.  A new solution is created with a project named TestSketch1.  The project has three files, with the following content;

  1. main.cpp – contains code to blink the led on the Arduino board.  This is so you can have a quick block of functional code.
  2. localdeploy.bat – this is the local deployment script.  This file is called by the deploy.bat script located in your c:\users\your_user_name\Documents\Atmel Studio\deploy.bat.  It gives you the opportunity to customize deployment for a particular sketch.  The localdeploy.bat is ready to deploy the hex file located in the Release directory, not debug.  This script reflects the port, speed and directory information provided to the installation script.  I have submitted internal enhancement request AVRSV-3699 to Atmel to have the $(Configuration) variable exported to indicate you are running in Release or Debug mode.  Until this issue is addressed the default hex file deployed is the one in the release directory. You can change the script to deploy from the Debug directory if necessary.
  3. readme.txt – This file contains a list of the Arduino libraries, which files you need to include and which libraries you need to add to the linker.

Before compiling the code you need to open the project properties (ALT-F7),  select All Configurations and under Toolchain\AVR/GNU Linker\Libraries add libcore.  See Figure 8.  There is a bug in Atmel Studio 6 that does not include the libraries added to a project template.  I have submitted internal bug AVRSV-3701 to Atmel for this issue.  Note the Library search path is automatically populated with the directory structure where the libraries are located. After adding the library you can go ahead and compile the code, then press the deploy button in the Productivity Toolbar.  You will see avrdude copy the hex file to the Arduino board and the onboard LED start flashing.

Add Core Library

Figure 8 – Add Core Library

Creating Arduino Libraries

To create an Arduino library, select File\New\Project and select the Arduino Library template from the list of available templates.  Name the library TestLib1 and change the directory as necessary.   A new directory is created with four files.

  1. foo.h and foo.cpp contain a dummy class
  2. localdeploy.bat is the deployment script responsible for deploying the library and header files to the Public directory of the Lib and Header created during installation.  As before only the Release version is deployed for the same reasons previously stated.
  3. readme.txt contains a blank file.

If you need a reference to libcore in your library you must add it as explained for the sketch.  Deploying the library copies all the header files and *.a files to the Public directories.


Adopting Atmel Studio has the potential to increase your productivity and expose you to advance concepts such as mixed language programming (C/C++ and Assembly).  If you are a Microsoft developer familiar with Visual Studio, you will feel right at home in Atmel Studio 6.  Let me know if the script has been of assistance transitioning out of the Arduino IDE.

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Reversing Bits In A Byte

I am working on a small project that requires interfacing a HD44780 20×4 LCD display to an ATTINY 2313 chip. While designing the PCB for this project, I needed to route the lower nibble of PORTB (PB0-PB3) to the high nibble of the LCD data (D4-D7). Keeping the port mapping straight (PB0->;D4, PB1->;D5, etc) required the addition of at least 6 vias. Reversing the order of the bits ( PB0->;d7, PB1->;D6,etc) required no additional vias, but the content of the lower nibble in PORTB would have to be reverse in code in order to align the data properly. This post documents the analysis I did on different bit reversing routines to determine which one was the most efficient for the task.

I found two viable C implementations to reverse the bits in a byte. Listing 1, illustrates the C code for the reverseByteWithForLoop implementation and the assembly code generated by the compiler. This functions loops through every bit in a byte and reverses every bit that is set. The function is 28 bytes long and takes 92 cycles to run when the data is 0x00 and 100 cycles when the data is 0xFF. It represents 1.37% of the 2K of flash memory in the ATTINY2313.

uint8_t reverseByteWithForLoop( uint8_t num )
uint8_t bit;
uint8_t output;
for( int count=1;count>;1;
output = output<;if(bit==1)
output = output+1;
return output;
/* ===============ASSEMBLY CODE ==================
 ldi	r18, 0x08			; 1 cycle
 ldi	r19, 0x00			; 1 cycle

 mov	r20, r24			; 1 cycle
 andi	r20, 0x01			; 1 cycle
 lsr	r24					; 1 cycle
 add	r25, r25			; 1 cycle
 cpi	r20, 0x01			; 1 cycle
 brne	.+2      			; 1 or 2 cycles
 subi	r25, 0xFF			; 1 cycle
 subi	r18, 0x01			; 1 cycle
 sbci	r19, 0x00			; 1 cycle
 brne	.-20     			; 2 cycles

 mov	r24, r25			; 1 cycle
 ret					; 4 cycle

Listing 2, contains the source code and the assembly code generated by the compiler for the function reverseByteWithShifts. This function is 32 bytes long and takes 19 cycles to run independently of the data. The size of the function represents 1.56% of the available flash memory in the ATTINY2313.

uint8_t reverseByteWithShifts( uint8_t x )
x = ((x >;>; 1) &amp; 0x55) | ((x <;<; 1) &amp; 0xaa);
x = ((x >;>; 2) &amp; 0x33) | ((x <;<; 2) &amp; 0xcc);
x = ((x >;>; 4) &amp; 0x0f) | ((x <;<; 4) &amp; 0xf0);
return x;
/* ===============ASSEMBLY CODE ==================
 mov    r25, r24            ; 1 cycle
add    r25, r25            ; 1 cycle
andi   r25, 0xAA           ; 1 cycle
lsr    r24                 ; 1 cycle
andi   r24, 0x55           ; 1 cycle
or     r25, r24            ; 1 cycle
mov    r24, r25            ; 1 cycle
add    r24, r24            ; 1 cycle
add    r24, r24            ; 1 cycle
andi   r24, 0xCC           ; 1 cycle
lsr    r25                 ; 1 cycle
lsr    r25                 ; 1 cycle
andi   r25, 0x33           ; 1 cycle
or     r24, r25            ; 1 cycle
swap   r24                 ; 1 cycle
ret                        ; 4 cycle

Listing 3, contains the last function which is my own implementation in assembly language. It is 12 bytes long and uses a loop to reverse all the bits in a byte. It takes this function 37 cycles to complete the task. The size of the function represents 0.59% of the available flash memory in the ATTINY2313.

#if (__GNUC__ * 100 + __GNUC_MINOR__) <; 303
#error &quot;This library requires AVR-GCC 3.3 or later, update to newer AVR-GCC compiler !&quot;

#include <;avr/io.h>;
.global reverseByte
.func   reverseByte
ldi        r25, 0x80
rol        r24
ror        r25
brcc       rotate_bit
mov        r24, r25

Table 1

Table 1, illustrates the characteristics previously outlined for each one of the functions. This analysis begs the question, which one of these functions is better? Well, it depends. If execution time is the primary concern, reverseByteWithShifts is the best choice at the expense of 1.56% of flash memory. On the other hand, if code size is the driving concern, reverseByte is the best candidate, but it takes twice as long as to run. ReverseByteWithForLoop is smaller than reverseByteWithShifts, but takes the longest to run. Its execution time is dependent on the input data, which makes it a bit more complicated to use in an project that requires accurate timing. To see other alternatives and how this topic evolved over time, visit AVRFreaks. As far as my project goes, reverseByte is the way to go since space concern is more important than execution timing.

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I2C Bus Scanner

Attaching components to an I2C bus can be a tedious experience when things do not go right.  Many factors ranging from bus termination, cross over cables and faulty devices can drive you to drink while debugging a problem.  I have been using a PDE created by Tod E. Kurt to perform bus scanning when troubleshooting connectivity to I2C components.  This post discusses modification made to the code provide by Tod and its conversion to an Arduino library.  The I2CScanner class is meant to be used as a debugging tool.  It assumes the bus is operational.  This class has little value if you are trying to bit bang an implementation of the I2C protocol.  The class satisfies two primary use cases.  Scanning the I2C bus and displaying the status of each address and determining if a device is listening to a particular address.


The following steps describe how to download and install the library.

  1. Download the file and unzip to a temporary directory.  It contains the files i2cscanner.h, i2cscanner.cpp and i2cBusScannerDemo.pde.
  2. Create a directory named i2cscanner in the library directory of your Arduino installation.
  3. Copy the files i2cscanner.h and i2cscanner.cpp to the newly created i2cscanner directory.
  4. Load the pde and run

Using The Library

Listing 1 contains the code of a demo PDE that tests the different methods of the class.  The method I2CScanBus::isAddressOnBus(byte address) has been very helpful while creating unit tests to test code that interface with I2C components.  The other method of the class, scanBus(..) and its overloads, allow finer control of the range of addresses to include and how to display the report generated when the I2C bus is scanned.

#include <Wire.h>
#include <i2cscanner.h>
using Utilities::I2CScanBus;
void setup()
/* Initialize libraries */

/* Scan I2C bus from address 1 - 127 */

/* Check if there is a device at address 103 */
Serial.print("\nSearching for address 103...");
if ( I2CScanBus::isAddressOnBus(103) )
Serial.println("Device Found");
Serial.println("Device NOT Found");

/* Scan I2C bus from address 10-20 */

/* Scan I2C bus from address 1 - 127, display addresses in HEX using two columns */
I2CScanBus::scanBus(1,127, I2CScanBus::NUM_HEX, I2CScanBus::TWO_COLUMN);

void loop()


Figure 1, shows the partial output of the report generated by running the code in the sample pde.  Addresses are displayed in decimal and hex.  Option to display the address in binary or octal is available as well.

Scan Bus Report

Figure 1 – Scan Bus Report

Once you have the sample sketch setup you can run it any time you need to scan the bus.  Alternatively you can reference the library and scan the bus from within your  project as needed.

 I2CScanner Source Code

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The I2C Bus Terminator – Hasta La Vista Baby!


After breaking the leg of another resistor while setting up a I2C bus.  It was time to permanently fix this problem.  The Atmega328 has one single I2C bus.  I am testing with software to bit bang data on any two pins of the AtMega328.  See SoftI2CMaster for more information.   I am also testing with the PCA9546A to provide access to multiple I2C buses.  Yes, pinky we are taking over the world tonight! The problem is all the I2C buses need to be properly terminated and bending the legs of the same set of resistors will eventually break them.  As my father used to say, they do not make ’em like they use to.


I need a solution that allows me to wire an I2C bus quickly and without bending pins.  The solution must be breadboard friendly and not complicated to use.  It should have connection pins so jumper wires are not required.  It took no time to create a simple three pin, two resistor solution that plugs in nicely into my Cohiba Breadboard main data bus.  It can also be used to terminate additional I2C buses.


I plan to create about 6 units to keep them around to breadboard prototypes.  The pullup resistors are 4.7K.  This schematic cannot be any simpler.  The following pictures list the schematic, PCB layout, 3D design and the first model.

I2C Bus Termination

I2C Bus Termination

I2C Bus Termination PCB

I2C Bus Termination PCB

I2C Bus Termination 3D

I2C Bus Termination 3D

I2C Side View

I2C Side View

I2C Breadboard View

I2C Breadboard View


I welcome with opened arms any solution or tool that allows me to maximize the time I spend working on projects as opposed to building infrastructure to prototype or test it.  Having a couple of these I2C bus terminators around, is a small but nice addition to the toolbox.

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I Want My Cohiba


I am organizing my workspace at home in order to streamline how I work on electronic projects.  As a result of this, I needed a second breadboard and multimeter next to my main computer on the first floor. All the heavy equipment (power supply, bench multimeter, solder iron, etc) would be moved to the basement.  While enjoying one of my last two Cohibas, I started jotting down the requirements for this project.


I tend to work on one project at the time.  I normally use the ETS-7000 Analog and Digital Trainer as my primary breadboard.  It’s been modified to hold two development boards with the Arduino form factor.  A Fez Panda and an Arduino Uno are part of my arsenal.  See Figure 1, Arduino Uno is missing from the picture.

ETS-7000 Analogue and Digital Trainer

Figure 1 - ETS-7000 Analogue and Digital Trainer

The ETS-7000 does the job, but there have been times when I want to breadboard a concept and the breadboard does not have enough real state or the Arduino Uno is connected to a bunch of wires.  This would be a good opportunity to ease some of these pains and create a platform on top of which I can build up in the future.  The new breadboard system should have the following features.

  1. Large real state to be able to work on complex projects or have multiple  prototypes on the board.
  2. Keep Arduino board fixed to prevent sliding or causing a short circuit.
  3. Portable in order to move between first floor and basement.
  4. Replaceable breadboards in order to swap projects.
  5. Multiple Arduino boards to work on communication projects between Arduinos.
  6. Large unconventional breadboard area in order to test breakout boards.

In a nutshell this covers everything that I need.  Instead of relying on supporting devices (power supplies, LED, switches, etc) permanently attached to the breadboard as in the case of the digital trainer, I would rely on external devices and breakout boards as much as possible.


I found the best deal for individual breadboards at Electronic Express.  To host the boards, an empty box of Cohibas with a drawer handle did the job perfectly.  The drawer handle levels both side of the box when it is open. I put the faceplate of an old clock in the front for decoration.   See Figure 2 for an outside view of the box.

Cohiba Board

Figure 2 - Cohiba Board

There is room for two Arduino boards and if the breadboards are empty, you can close the box with the Arduino boards inside.  See Figure 3, for an internal view of the right hand side of the board.

Cohiba Board 2

Figure 3 - Right Hand Side Of Board

The breadboards are attached to a 1/2  inch, 7 x 9 board, that fits nicely in the box of Cohibas.  Attaching the breadboard to the wooden board allows them to be swapped in and out of the box as needed.  The left hand side of the board is fixed and it is screwed to the drawer handle with a flat nut.  The Arduinos are attached independently and can be swapped if necessary.  Figure 4, shows the Cohiba box open with all the breadboard real state.

Full Cohiba Board

Figure 4 - Full Cohiba Board

The outer bus is used as a data bus for I2C and SPI.  The bottom of the left hand side has two breadboards without buses.  This arrangement allows me to use larger than normal breakout boards.  Staples are used to connect the buses as needed.


Independently of the project or field, the ability to make the most of the resources you have is one of the best tools in your arsenal.  You can get empty cigar boxes from your local cigar store.  You may get them for free or for a couple of dollars.  Between cutting and sanding the boards, using a Dremel to trim the connection points of the outer data bus,  it took me a couple of hours to put this project together.  Now all I need is another box with fresh Cohibas to get started on the next project!

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