Linux cross-compilation¶

RF24 library supports cross-compilation. Advantages of cross-compilation:

• development tools don’t have to be installed on target machine

• resources of target machine don’t have to be sufficient for compilation

• compilation time can be reduced for large projects

Following prerequisites need to be assured:

• ssh passwordless access to target machine Here is a hint

• sudo of a remote user without password Here is a hint

• cross-compilation toolchain for your target machine; for RPi

  git clone https://github.com/raspberrypi/tools rpi_tools
  

  and cross-compilation tools must be in PATH, for example

  export PATH=$PATH:/your/dir/rpi-tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin
  

Cross compilation steps¶

1. clone RF24 to a machine for cross-compilation

   git clone https://github.com/nRF24/RF24
   cd RF24
   

2. configure for cross compilation

   ./configure --remote=pi@target_linux_host
   

   eventually

   ./configure --remote=pi@target_linux_host --driver=<driver>
   

3. build

   make
   

4. (optional) install library to cross-compilation machine into cross-exvironment - important for compilation of examples

   sudo make install
   

5. upload library to target machine

   make upload
   

6. (optional) compile examples

   cd examples_linux
   make
   

7. (optional) upload examples to target machine

   make upload
   

Cross comilation steps for python wrapper¶

Prerequisites¶

• Python setuptools must be installed on both target and cross-compilation machines

  sudo pip install setuptools
  

  or

  sudo apt-get install python-setuptools
  

Installation steps¶

1. Assure having libboost-python-dev library in your cross-compilation environment. Alternatively, you can install it into your target machine and copy /usr and /lib directories to the cross-compilation machine. For example

   mkdir -p rpi_root && rsync -a pi@target_linux_host:/usr :/lib rpi_root
   export CFLAGS="--sysroot=/your/dir/rpi_root -I/your/dir/rpi_root/usr/include/python2.7/"
   

2. Build the python wrapper

   cd pyRF24
   ./setup.py build --compiler=crossunix
   

3. Make the egg package

   ./setup.py bdist_egg --plat-name=cross
   

   dist/RF24-<version>-cross.egg should be created.

4. Upload it to the target machine and install there:

   scp dist/RF24-*-cross.egg pi@target_linux_host:
   ssh pi@target_linux_host 'sudo easy_install RF24-*-cross.egg'