I admit: my work laptop machine is running a Windows 10 OS by default. But this does not prevent me running Linux in a Virtual Machine (VM). Each host platform has its benefits, and I don’t feel biased to one or the other, but I have started using Ubuntu more and more, simply because I have worked more on Embedded Linux projects. While I have used mostly Windows with Eclipse for NXP LPC, Kinetis, and i.MX platforms in the past, I started using Ubuntu, too, from last year with the NXP MCUXpresso SDK. I did not find much documentation about this on the web, so I thought it might be a good idea to write a tutorial about it. So, here we go…

Building NXP MCUXpresso SDK on Linux Ubuntu

Outline

This tutorial shows how to install and develop on Linux with the NXP MCUXpresso SDK. It goes through the steps all the needed pieces and to build one of the SDK example projects.

If you want to develop the easy way with MCUXpesso SDK using a GUI: The MCUXpresso IDE (Eclipse based) runs on Ubuntu (and Windows and Mac) too. This article uses make files and no GUI for a ‘headless’ or ‘GUI-less’ environment.

This is what I’m using in this tutorial:

• Oracle VirtualBox V6.0.4 from https://www.virtualbox.org/
• Ubuntu 18.0.4 LTS: https://www.ubuntu.com/download/desktop
• NXP FRDM-K64F Board: https://www.nxp.com/freedom
• NXP MCUXpresso SDK V2.5.0 for FRDM-K64F: https://mcuxpresso.nxp.com
• GNU Toolchain for ARM gcc-arm-none-eabi-8-2018-q4-major: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads
• cmake version 3.10.2:

Blinky on FRDM-K64F Board

Linux Host

I recommend using Ubuntu Linux. I’m using it in a VM (Virtual Machine) on Windows 10 with the Oracle VirtualBox. There are plenty of tutorials available on the internet about installing Ubuntu on VirtualBox if you are not familiar with it.

NXP MCUXpresso SDK

Select and configure the SDK on https://mcuxpresso.nxp.com. The important part is to select Linux as Host OS and GCC ARM Embedded as toolchain:

MCUXpresso SDK

Then, click on ‘Download SDK’ and download the archive to the user home directory and extract it there in a subdirectory:

$ cd ~
$ mkdir MCUXpresso
$ cd MCUXpresso
$ mkdir SDK_2.5.0_FRDM-K64F
$ cd SDK_2.5.0_FRDM-K64F

Place the SDK .tar.gz file into that created folder. Unzip the downloaded SDK file:

$ gunzip SDK_2.5.0_FRDM-K64F.tar.gz

Then, untar the archive:

tar -xvf SDK_2.5.0_FRDM-K64F.tar

Extraced SDK Files

Installing CMake

By default, the SDK is using CMake and not directly normal make files. As CMake is not installed by default in my Ubuntu distribution, I have to add it:

$ sudo apt install cmake

CMake is a cross-platform make file  *generator*. As with the make file syntax, it takes some time to learn using. To learn more about CMake, there are plenty of resources available online, a good starting point is https://cmake.org/.

I’m using cmake 3.10.2. The SDK documentation recommends using an older version 3.0.x. Using the 3.10 version will show warnings like ‘The CMAKE_FORCE_C_COMPILER macro is deprecated. Instead just set CMAKE_C_COMPILER and allow CMake to identify the compiler.’ because the SDK cmake files are not compatible with newer cmake versions. The warnings are annoying, but do not affect the functionality so they can be ignored.

Installing GNU ARM Toolchain for Embedded

To develop with the SDK, I have to install a cross toolchain, available from https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads

I don’t want to have the toolchain installed for everyone on my Linux, so I install it locally into a ‘opt’ folder inside my user home directory:

The reason for this is to separate different GNU ARM Embedded Toolchains for different projects. If I would add it to the global path/system, separation would be very difficult.

$ mkdir ~/opt
$ cd ~/opt

The current release is gcc-arm-none-eabi-8-2018-q4-major-linux.tar.bz, which I download with:

$ wget https://developer.arm.com/-/media/Files/downloads/gnu-rm/8-2018q4/gcc-arm-none-eabi-8-2018-q4-major-linux.tar.bz2

Unzip the archive:

tar xjf gcc-arm-none-eabi-8-2018-q4-major-linux.tar.bz2

Finally, change the permissions to read-only:

chmod -R -w "${HOME}"/opt/gcc-arm-none-eabi-7-2017-q4-major

Verify that the compiler is working:

$ ~/opt/gcc-arm-none-eabi-8-2018-q4-major/bin/arm-none-eabi-gcc --version

... which returns the following:

arm-none-eabi-gcc (GNU Tools for Arm Embedded Processors 8-2018-q4-major) 8.2.1 20181213 (release) [gcc-8-branch revision 267074]
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

CMake Environment

CMake needs a variable set to find the compiler. This can be done with:

$ export ARMGCC_DIR=~/opt/gcc-arm-none-eabi-8-2018-q4-major

To make it permanent for the user, it can be added to the ~/.bashrc file:

$ nano ~/.bashrc

And then, add it to the file, which gets executed every time I log in as this user.

Setting Environment

Use CTRL+X to exit nano and to save the file.

Building Example SDK Projects

In the next step, I’m going to build one of the example projects: the LED Blinky one:

$ cd ~/MCUXpresso/SDK_2.5.0_FRDM-K64F/boards/frdmk64f/demo_apps/led_blinky/armgcc

LED Blinky Example Projects

This folder contains several *.bat files (left-over from the Windows world?). Relevant are the Shell script *.sh script files:

• clean.sh: used to clean the build files
• build_release.sh: generate make file for a release build
• build_debug.sh: generate make file for a debug build
• build_all.sh: build a make file for release and debug build

The shell script to generate the make file are using cmake (see above) with all the necessary information for cmake in the CMakeLists.txt file.

To build a make file for both debug version:

$ ./build_debug.sh

Running build_debug.sh

Beside of generating the make file, it generates the binary too in the ‘debug’ output folder:

Generated Files

With the file command, I can verify that indeed the correct binary has been produced:

$ file debug/led_blinky.elf

ELF 32-bit Executable

Because CMake has generated all the needed make files, I can now build the project with:

$ make

To clean it, I can use:

$ make clean

That’s it.

Summary

With this tutorial, I showed the installation of the necessary tools (SDK, cmake, GNU ARM for Embedded toolchain) and how to build example projects.

In a next part, I’ll touch on the debugging part with gdb. Until then, I hope you find this one useful.

Happy Linuxing!

Links

• Oracle VirtualBox: https://www.virtualbox.org/
• Ubuntu Linux: https://www.ubuntu.com
• NXP MCUXpresso SDK web site: https://mcuxpresso.nxp.com
• NXP FRDM-K64F Board: https://www.nxp.com/support/developer-resources/evaluation-and-development-boards/freedom-development-boards/mcu-boards/freedom-development-platform-for-kinetis-k64-k63-and-k24-mcus:FRDM-K64F
• GNU Toolchain for ARM Embedded: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads
• CMake: https://cmake.org/
• MCUXpresso IDE: http://www.nxp.com/mcuxpresso/ide