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Build apps without firmware

Build applications without building the firmware

If you do not want to compile the complete firmware image, but still want to make changes to the basestation/client, use this guide for how to cross-compile the applications.

1. Get ARM toolchain

Already got Xilinx SDK installed?

If you already have the Xilinx SDK installed, you can skip this step. You may have to add the toolchain folder to your path, though. (add export PATH=$PATH:/opt/Xilinx/SDK/2018.2/gnu/aarch32/lin/gcc-arm-linux-gnueabi/bin to ~/.profile)

First, the arm toolchain has to be installed. Again, a more detailed instruction can be found here.

We use linaro toolchain 7.2-2017.11, download it from here (I've used x86_64 version).

Unpack it and copy it to /usr/local/bin/

tar -xf gcc-linaro-7.2.1-2017.11-x86_64_arm-linux-gnueabihf.tar.xz
sudo mv gcc-linaro-7.2.1-2017.11-x86_64_arm-linux-gnueabihf/ /usr/local/bin/gcc-linaro-7.2.1

Next, add the toolchain location to the path variable. To make this permanent, edit ~/.profile and add the following lines:

# add linaro gcc to path
export PATH=$PATH:/usr/local/bin/gcc-linaro-7.2.1/bin

Log off and on to apply the changes.

2. Get custom Pluto sysroot

To successfully cross-compile, the pluto root directory has to be known. We use a custom sysroot, that can be fetched in the release section of the repository.

Download it and copy the folder to your home directory and set the environment variable PLUTO_SYSROOT_DIR. It will be used by some of the following scripts.

export PLUTO_SYSROOT_DIR=$HOME/pluto-0.31.sysroot

3. Compile libraries

We have to compile libfftw on our own, because liquid-dsp requires the single precision fftw3 lib, but adalm pluto only has the double precision version installed by default.

Get the tarball from and unpack it. We are using FFTW 3.3.8.

tar xzfv fftw-3.3.8.tar.gz
cd fftw-3.3.8
./configure --host=arm-linux-gnueabihf --enable-float --enable-shared --prefix="$PLUTO_SYSROOT_DIR/usr/" CC="arm-linux-gnueabihf-gcc --sysroot=$PLUTO_SYSROOT_DIR/"
make install

This will install the shared library to the sysroot directory.

libfec and liquid-dsp can be configured and cross-compiled with the follwing commands

git clone --recursive

cd HNAP4PlutoSDR/libfec
./configure arm --host=arm-linux-gnueabihf  --prefix="$PLUTO_SYSROOT_DIR/usr/" CC="arm-linux-gnueabihf-gcc --sysroot=$PLUTO_SYSROOT_DIR/"
make install

cd ../liquid-dsp
apt install automake autoconf
./configure arm --host=arm-linux-gnueabihf  --prefix="$PLUTO_SYSROOT_DIR/usr/" CC="arm-linux-gnueabihf-gcc --sysroot=$PLUTO_SYSROOT_DIR/"
sed -i '/rpl_realloc/d' config.h
sed -i '/rpl_malloc/d' config.h
make install

NOTE: For liquid-dsp, the configure script does not correctly detect malloc and realloc C functions, and thus make fails! We use the sed commands to fix this.

4. Compile apps

The apps are built using cmake. The target names are basestation client and client-calib.

mkdir cmake-build-release-arm
cd cmake-build-release-arm
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=CmakeArmToolchain.cmake ..
make basestation
make client
make client-calib

5. Upload everything to pluto

Configure your Host PC as described in the Host PC configuration section.

To upload applications, do:

cd HNAP4PlutoSDR/cmake-build-release-arm/
scp basestation client client-calib plutosdr:/root/

Now, you can log in to the pluto and run the applications. They are located in /root/.

Note: every time Pluto reboots, The changed application files are lost. To make the changes permanent, the firmware image has to be changed.

Host PC configuration

In order to ease development with multiple plutos connected to your PC, you can configure your ssh client.

The host key of the pluto changes every time the device reboots, so for convenience add the follwing to ~/.ssh/config:

Host plutosdr
   HostKeyAlias plutosdr
   CheckHostIP no
   User root
   ChallengeResponseAuthentication no

Then the device can be accessed with ssh plutosdr (password: analog).