Compiling

Now that we’ve installed Apache NuttX prerequisites and downloaded the source code, we are ready to compile the source code into an executable binary file that can be run on the embedded board.

Initialize Configuration

The first step is to initialize NuttX configuration for a given board, based from a pre-existing configuration. To list all supported configurations you can do:

$ cd nuttx
$ ./tools/configure.sh -L | less

The output is in the format <board name>:<board configuration>. You will see that generally all boards support the nsh configuration which is a good sarting point since it enables booting into the interactive command line NuttShell (NSH).

To choose a configuration you pass the <board name>:<board configuration> option to configure.sh and indicate your host platform, such as:

$ cd nuttx
$ ./tools/configure.sh -l stm32f4discovery:nsh

The -l tells use that we’re on Linux (macOS and Windows builds are possible). Use the -h argument to see all available options.

Customize Your Configuration (Optional)

This step is optional. Right now, this is mainly to get familiar with how it works– you don’t need to change any of the options now, but knowing how to do this will come in handy later.

There are a lot of options. We’ll cover a few of them here. Don’t worry about the complexity– you don’t have to use most of the options.

$ cd nuttx/
$ make menuconfig

Todo

Explain some useful options.

Build NuttX

We can now build NuttX. To do so, you can simply run:

$ cd nuttx/
$ make make

The build will complete by generating the binary outputs inside nuttx directory. Typically this includes the nuttx ELF file (suitable for debugging using gdb) and a nuttx.bin file that can be flashed to the board.

To clean the build, you can do:

$ make clean

Warning

At the moment it is recommended that after modifying the configuration you first clean before building again. This is currently worked on.

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Next up is Running.