Skip to content

Latest commit

 

History

History
65 lines (51 loc) · 2.73 KB

ARCHITECTURE.md

File metadata and controls

65 lines (51 loc) · 2.73 KB
Raw

libhal starter architecture

src/main.cpp

It contains the main loop of the application. In this example, it just prints "Hello, World" and toggles an LED on and off. This application will reset after 10 iterators just to demonstrate the capability.

include/application.hpp

This file defines the resource_list structure which holds optional pointers to the led, console, clock interfaces and reset callback. Modify this structure to change the set of required drivers, settings, and memory resources for the application. initialize_platform functions that must be implemented in the platform/ file.

CMakeLists.txt

This is the build file for the project. It sets the minimum required version of CMake, names the project, and sets the platform library. It also defines the sources to compile and the libraries to link against. Finally, it sets up the post-build steps with libhal_post_build.

Profile Environment Variables

At the start of the cmake file you will encounter these lines:

# Always check that the $ENV{LIBHAL_PLATFORM_LIBRARY} & $ENV{LIBHAL_PLATFORM}
# environment variables are set by the profile.
if("$ENV{LIBHAL_PLATFORM_LIBRARY}" STREQUAL "")
    message(FATAL_ERROR
        "Build environment variable LIBHAL_PLATFORM_LIBRARY is required for " "this project.")
endif()
if("$ENV{LIBHAL_PLATFORM}" STREQUAL "")
    message(FATAL_ERROR
        "Build environment variable LIBHAL_PLATFORM is required for "
        "this project.")
endif()

libhal conan profiles utilize environment variables as a generic means to communicate to build systems the name of the libhal binary package, $ENV{LIBHAL_PLATFORM_LIBRARY} and the name of the target platform $ENV{LIBHAL_PLATFORM}. If the developer wishes to use a different build system compatible with conan, they will need to use their build system's means to acquire environment variables in order link against the correct library and select the correct platform source file.

platforms/lpc4078.cpp

This file provides an implementation for initialize_platform, for the LPC4078 platform. In initialize_platform, it sets the clock speed, configures a uart peripheral for console output, and sets up an output pin for the led. Each driver is statically allocated. The returned resource_list has the pointers to each statically allocated peripheral and a reset callback that can resets the microcontroller.

platforms/*.cpp

Just like platforms/lpc4078.cpp but for any other platforms. It's important to note that the specifics of the initialize_platform function and the peripherals used will likely vary between different platforms but sometimes they don't. As an example the lpc4074.cpp file just includes directly the lpc4078.cpp because those are identical.