The AVR toolchain used by the Arduino IDE
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AArch64 support and download URL fix
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AVR Toolchain for Arduino

This is the AVR Toolchain used in the Arduino IDE.

As soon as Atmel ships a newer toolchain, we pull the source code, patch it with some user contributed patches and deliver it with the Arduino IDE. Therefore, the resulting binaries may differ significantly from Atmel's. And you should start blaming us if things are not working as expected :)


Edit the build.conf file, currently the only thing worth changing is AVR_VERSION on the first line to match whatever the latest version is.

At time of writing, the latest toolchain available is based on Atmel 3.5.4 version. It contains:

  • binutils-2.26
  • gcc-4.9.2
  • avr-libc-2.0.0
  • gdb-7.8


Setup has been done on partially set up development machines. If, trying to compile on your machine, you find any package missing from the following list, please open an issue at once! We all can't afford wasting time on setup :)

To just build, after getting the requirements...


after a successful compile the binaries etc will be found in objdir

To package, after getting the requirements...


Debian requirements

sudo apt-get install build-essential gperf bison subversion texinfo zip automake flex libtinfo-dev pkg-config

Mac OSX requirements

You need to install MacPorts: Once done, open a terminal and type:

sudo port selfupdate
sudo port upgrade outdated
sudo port install wget +universal
sudo port install automake +universal
sudo port install autoconf +universal
sudo port install gpatch +universal
sudo port install gsed +universal

Windows requirements

You need to install Cygwin: Once you have run setup-x86.exe, use the Search text field to filter and select for installation the following packages:

  • git
  • wget
  • unzip
  • zip
  • gperf
  • bison
  • flex
  • make
  • patch
  • automake
  • autoconf
  • gcc-g++
  • texinfo (must be at version 4.13 since 5+ won't work)
  • libncurses-devel

A note on texinfo: due to dependencies, each time you update/modify your cygwin installation (for example: you install an additional package), texinfo will be upgraded to version 5+, while you need version 4+! Easy solution: as soon as you've installed the additional package, re-run cygwin setup, search texinfo, triple click on "Keep" until you read version 4, then click next.

You also need to install MinGW: Once you have run mingw-get-setup.exe, select and install (clicking on "Installation" -> "Apply changes") the following packages:

  • mingw-developer-toolkit
  • mingw32-base
  • mingw32-gcc-g++
  • msys-base
  • msys-zip

Upstream credits

Build process ported from Debian. Most patches come from Atmel. Thank you guys for your awesome work.


Consult the list of contributors.


The bash scripts are GPLv2 licensed. Every other software used by these bash scripts has its own license. Consult them to know the terms.