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Using Arduino with Ada

Building avr-gnat for AVR-Ada

None of the Linux distributions ship Ada-enabled avr-gcc (avr-gnat) by default. And building GNAT for AVR a bit tricky. So, to help the situation I have tried to gather a little help for that.

To build AVR-Ada applications, you need following software packages

  • avr-binutils
  • avr-gcc + avr-gnat
  • avr-libc
  • avr-ada itself

Since GNAT is written in Ada, you need native Ada compiler on your system. In most cases, this means GNAT (installed using the package manager of your Linux distribution). But, one should notice that to compile GNAT you need to have same version or older version of GNAT installed. Using newer version of GNAT to compiler order version is not supported. For example, you cannot compile GNAT 4.2 using GNAT 4.6.

Ok, that was the introduction. Now, let's try to install avr-gcc 4.7.0 with Ada support (GNAT) on Fedora 16.

Installing GNAT 4.7

Since we are building GNAT 4.7 using GNAT 4.6, everything should go smoothly.

Commands are following:

yum install mpfr-devel gmp-devel bison make autoconf automake libtool flex gcc-gnat
wget ftp://ftp.mirrorservice.org/sites/sourceware.org/pub/gcc/releases/gcc-4.7.0/gcc-4.7.0.tar.gz
tar zxf gcc-4.7.0.tar.gz
mkdir gcc-obj-470
cd gcc-obj-470
../gcc-4.7.0/configure --enable-languages=c,ada \
  --prefix=$HOME/programs/gnat470 --disable-multilib
make bootstrap
make install

When 'make install' finishes, you should have (native/normal) gnat 4.7 in $HOME/programs/gnat470 directory.

Installing avr-binutils

Binutils package provides tools like 'as', 'ld', and 'objcopy', which are necessary when gcc compiles something. Binutils for AVR can be installed in following way:

wget http://ftp.uni-kl.de/pub/gnu/binutils/binutils-2.20.1a.tar.bz2
tar jxf binutils-2.20.1a.tar.bz2
git clone git://avr-ada.git.sourceforge.net/gitroot/avr-ada/avr-ada
cd binutils-2.20.1
for a in ../avr-ada/patches/binutils/2.20.1/*.patch;
do
    patch -p0 < $a || fail "avr-binutils: patch $a"
done
cd ..
mkdir binutils-obj
cd binutils-obj
../binutils-2.20.1/configure --target=avr --program-prefix=avr- \
  --disable-shared --disable-nls --enable-commonbfdlib=no \
  --disable-werror --prefix=$HOME/programs/avrada
make
make install

The patching part is there, because AVR-Ada repository includes some patches with improve AVR support of binutils and it is a good idea to use the patches.

Installing avr-gcc with Ada support

Now we are ready to compile avr-gcc. Notice how we set the PATH environment variable that the gcc build process picks up our custom gnat 4.7.0. Also, our new avr-binutils tools need to be in PATH.

export PATH=$HOME/programs/gnat470/bin:$HOME/programs/avrada/bin:$PATH
mv gcc-4.7.0 gcc-4.7.0-native
git clone git://avr-ada.git.sourceforge.net/gitroot/avr-ada/avr-ada
tar zxf gcc-4.7.0.tar.gz
cd gcc-4.7.0
for a in ../avr-ada/patches/gcc/4.7.0/*.patch;do patch -p0 < $a;done
cd ..
mkdir avr-gcc-obj
cd avr-gcc-obj
../gcc-4.7.0/configure --target=avr --program-prefix=avr- \
            --disable-shared --disable-nls --disable-libssp \
            --with-system-zlib \
            --disable-libada \
            --enable-languages=ada,c,c++ --enable-cpp --with-dwarf2 \
            --enable-version-specific-runtime-libs \
            --prefix=$HOME/programs/avrada
sed -i -e 's/$(STAMP)/echo timestamp >/' ../gcc-4.7.0/gcc/config/avr/t-avr
make
make install

Steps explained

export PATH=$HOME/programs/gnat470/bin:$HOME/programs/avrada/bin:$PATH

Put gcc/gnat 4.7.0 to PATH. Also, put avr-binutils to PATH.

mv gcc-4.7.0 gcc-4.7.0-native

Move previous gcc-4.7.0 source directory out of the way.

git clone git://avr-ada.git.sourceforge.net/gitroot/avr-ada/avr-ada

Clone the official avr-gcc repository, which contains some avr-gcc specific patches. You need to do this only if you haven't cloned the repository in earlier steps.

tar zxf gcc-4.7.0.tar.gz

Extract gcc-4.7.0 sources (since you move the previous source directory), to have fresh untouched gcc-4.7.0 sources.

cd gcc-4.7.0
for a in ../avr-ada/patches/gcc/4.7.0/*.patch;do patch -p0 < $a;done
cd ..

Enter the gcc-4.7.0 source directory and apply AVR and AVR-Ada specific patches to gcc sources from the avr-ada repository.

mkdir avr-gcc-obj

Create a separate build directory for gcc object files.

cd avr-gcc-obj
../gcc-4.7.0/configure --target=avr --program-prefix=avr- \
            --disable-shared --disable-nls --disable-libssp \
            --with-system-zlib \
            --disable-libada \
            --enable-languages=ada,c,c++ --enable-cpp --with-dwarf2 \
            --enable-version-specific-runtime-libs \
            --prefix=$HOME/programs/avrada

Configure gcc to be cross-compiler with avr target. We disable a lot of unnecessary things, and enable three languages: Ada, C, and C++.

In addition, we disable libada (Ada runtime) compilation. This means that gnattools (avr-gnatmake, avr-gnatclean, etc.) will use Ada runtime from the host system. If the Ada runtime on the host system is from different version of gcc, then gnattools will not work.

sed -i -e 's/$(STAMP)/echo timestamp >/' ../gcc-4.7.0/gcc/config/avr/t-avr

This line fixes a little bug in gcc sources. STAMP variable is not defined in t-avr file and easiest work-around is to replace it with 'echo' command.

make

Compile the code.

make install

Install everything.

Installing avr-libc

AVR-Ada depends on avr-libc, so you need to build it also.

export PATH=$HOME/programs/avrada/bin:$PATH
wget http://download.savannah.gnu.org/releases/avr-libc/avr-libc-1.8.0.tar.bz2
tar jxf avr-libc-1.8.0.tar.bz2
cd avr-libc-1.8.0
./configure --host=avr --prefix=$HOME/programs/avrada
make
make install

Installing AVR-Ada

Finally, we are ready to install AVR-Ada. We will fetch the latest version from AVR-Ada git repository, since it contains many improvements over AVR-Ada 1.1.

export PATH=$HOME/programs/avrada/bin:$PATH
git clone git://avr-ada.git.sourceforge.net/gitroot/avr-ada/avr-ada
cd avr-ada
./configure
make
make install_rts
cd avr/avr_lib
sed -i -e 's/stamp-libs: $(thread_libs)/stamp-libs:/' Makefile
make
cd ../..
make install_libs

The 'sed ...' line is there to disable avr-threads support, since it assumes Windows build system by default and we are building on Linux. If one feels brave enough, he/she can skip the sed command and try to build the avr-threads part also.

When 'make install_libs' completes, you should have complete AVR-Ada setup at $HOME/programs/avrada.

Testing the setup

To verify that you can actually compile AVR-Ada programs, you can download some example code from my bitbucket repositories and build them.

export PATH=$HOME/programs/avrada/bin:$PATH
hg clone https://bitbucket.org/tkoskine/arduino-hello-uart
cd arduino-hello-uart
make

After successful build, there is file 'hello.hex' in the arduino-hello-uart directory. If you have Arduino UNO, you can upload the file on it using avrdude tool.

sudo avrdude -c arduino -p atmega328p -P /dev/ttyACM0 -b 115200 -U flash:w:hello.hex
# or simply "make upload-uno"

Final notes

Some final notes:

  • Be careful with the version numbers. I use somewhat old releases on purpose, since they are proven to work with AVR-Ada better than later releases.
  • If you get some strange compiler errors, check that you compile the code with correct GNAT. ("gnatls -v" shows the version number of GNAT)
  • It is possible that AVR-Ada installation scripts do not set all permission bits properly, so AVR-GNAT (avr-gnatmake) might recompile some parts of AVR-Ada when you compile your AVR-Ada applications.
  • Root (sudo) rights are necessary only with avrdude, other parts of this guide can be done with normal user rights.

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