Building and debugging emb-template

Once you checked out https://github.com/DataArt/ebc-template repository and created a separate directory for out-of-source build, you need to run a command like this:

cmake ../mbed-template/ -DCMAKE_TOOLCHAIN_FILE=../mbed-template/lm3s6965evb.cmake \
    -DTOOLCHAIN_PATH=~/gcc-arm-none-eabi/bin -DQEMU_PATH=~/qemu-arm/bin

The first argument of the cmake command specifies a directory that contains CMakeLists.txt file - a file that holds project description, and defines rules of how to compile and link the project.

DCMAKE_TOOLCHAIN_FILE argument specifies so called toolchain file. This file basically redefines standard cmake definitions. It can define the way cmake actually invoke particular command. For instance, if you need to use arm-none-eabi-gcc executable insteard of gcc, this file is a right place to acomplish this.

Argument DTOOLCHAIN_PATH is specific to ebc-template project. You may find it usefull if you have a few arm-none-eabi toolchains installed in your system. It allows you to set a path to bin directory of particular toolchain you want to use during the build.

Debugging an application

By default all projects undef ebc-template repository get compiled in "release" mode. This means that the compiler will optimize an application code and will not include any debug information into binary output. So later on you will not be able to debug your C/C++ code.

So in order to tell cmake that you actually need a debug build you need to add

-DCMAKE_BUILD_TYPE=Debug

argument.

Then you can start a gdbserver using

make gdbserver

command. Depending on whether you building an application for QEMU or TIVA launchpad the command will execute either qemu in gdbserver mode or openocd gdbserver.

In either way then you can connect to the gdbserver by executing command:

make cgdb

The command will start cgdb application and connect to gdbserver.

If you are connected to real hardware through openocd, the sequence of commands:

monitor reset halt
load
monitor reset halt
break main
continue

will upload the binary image into microcontroller's flash memory, set a break point to the main function and finally continue execution.

Unfortunatly by the moment qemu's gdbserver does not support monitor reset functionality and so you need to restart qemu each time you recompile the application.

If you do not want to debug your application using TUI debugger like cgdb, another option for you is to set up IDE with GUI. For more details on thie please see blog post.