Developing for FRDM-KL25Z platform in Linux – Crosstoolchain

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Table of contents:

1. Introduction
2. Crosstoolchain
3. Building
4. Flashing
5. Debugging

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In order to compile software for FRDM-KL25Z board we must be able to generate object code for ARM CPUs. It’s very likely that your Gentoo system runs on a non-ARM computer, so we require tools for handling generation and manipulation of object code targeted to a CPU architecture other that your computer’s.

Install crossdev, the Gentoo cross-toolchain generator:

localhost ~ # emerge sys-devel/crossdev

Have crossdev to build C cross-compiler, libc and other build tools for ARM CPUs:

localhost ~ # crossdev -t arm-none-eabi
-----------------------------------------------------------
 * crossdev version:      20131107
 * Host Portage ARCH:     amd64
 * Target Portage ARCH:   arm
 * Target System:         arm-none-eabi
 * Stage:                 3 (C compiler & libc)
 * ABIs:                  default

 * binutils:              binutils-[latest]
 * gcc:                   gcc-[latest]
 * libc:                  newlib-[latest]



 * Log: /var/log/portage/cross-arm-none-eabi-binutils.log
 * Emerging cross-binutils ... [ ok ]
 * Log: /var/log/portage/cross-arm-none-eabi-gcc-stage1.log
 * Emerging cross-gcc-stage1 ... [ ok ]
 * Log: /var/log/portage/cross-arm-none-eabi-newlib.log
 * Emerging cross-newlib ... [ ok ]

Now your Gentoo system contains a damn good GNU cross-toolchain that can build code for ARM CPUs. All tools are prefixed by arm-none-eabi- indicating their purpose of being cross-tools for ARM in your non-ARM system:

user@localhost ~ $ cd /usr/bin
user@localhost /usr/bin $ ls arm-none-eabi-*
arm-none-eabi-addr2line  arm-none-eabi-gcc-4.8.2   arm-none-eabi-nm
arm-none-eabi-ar         arm-none-eabi-gcc-ar      arm-none-eabi-objcopy
arm-none-eabi-as         arm-none-eabi-gcc-nm      arm-none-eabi-objdump
arm-none-eabi-c++filt    arm-none-eabi-gcc-ranlib  arm-none-eabi-pkg-config
arm-none-eabi-cpp        arm-none-eabi-gcov        arm-none-eabi-ranlib
arm-none-eabi-cpp-4.8.2  arm-none-eabi-gcov-4.8.2  arm-none-eabi-readelf
arm-none-eabi-dwp        arm-none-eabi-gdb         arm-none-eabi-run
arm-none-eabi-elfedit    arm-none-eabi-gprof       arm-none-eabi-size
arm-none-eabi-emerge     arm-none-eabi-ld          arm-none-eabi-strings
arm-none-eabi-fix-root   arm-none-eabi-ld.bfd      arm-none-eabi-strip
arm-none-eabi-gcc        arm-none-eabi-ld.gold

For quick checking the usability of the cross-compiler, you can create a file named hello.c containing:

#include <stdio.h>

int main() {

        printf("Hello world\n");
        return 0;

}

Let’s see if the cross-compiler can generate executables for ARM:

user@localhost ~ $ arm-none-eabi-gcc -o hello hello.c 
user@localhost ~ $ file hello
hello: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), statically linked, not stripped

Looks good.

Next in Building we’ll use the cross-toolchain to build an application developed specifically for the FRDM-KL25Z board.