【BearPi-HM Micro】Part 4: Familiar with the Openharmomy compilation framework and serial port interactive output

数码小叶

【BearPi-HM Micro】Part 4: Familiar with the Openharmomy compilation framework and serial port interactive output [Copy link]

After a few days of practice, I have a better understanding of Openharmomy, such as how to compile a simple program into the system.

First, you need a source code program to implement the function, such as helloworld.c. You also need a BUILD.gn file. The .gn file is a compilation build file, similar to Cmake. Compared with Cmake, when the project scale increases to an unimaginable level, the compilation speed and the division of project modules become particularly important, and gn solves these two problems very well. The Openharmomy document introduces the relevant .gn coding standards.

The basic structure of BUILD.gn is as follows

import("//build/lite/config/component/lite_component.gni")

executable("生成的库名称") {
    output_name = "可执行文件名称"
    sources = [ "源文件" ]
    include_dirs = []
    defines = []
    cflags_c = []
    ldflags = []
}

lite_component("lite组件名") {
    features = [
        ":库文件",
    ]
}

Import the gni component, compile the source code into a library file, and then package the library file into a lite component. At the same time, define the name of the output executable file.

Similar to Cmake, BUILD.gn is also case sensitive. I made a mistake at first and it kept failing to compile.

The next step is to configure the ~\bearpi\project\bearpi-hm_micro_small\build\lite\components\applications.json file and add the lite component just defined

Save after adding, and then modify the single board configuration file ~\bearpi\project\bearpi-hm_micro_small\vendor\bearpi\bearpi_hm_micro\config.json

When you unbox it, you will see the built-in lock screen. The components defined by its functions are also seen here. Going back to the applications.json file just now, you can also find the screensaver related content. Compared with the simple helloworld serial port output, the lock screen relies on more components.

At the same time, it can also explain that after burning the source code in the previous article, there are only two applications. Here you can see the definition

Go to this directory and look for the original pictures of the lock screen. Pictures of the four seasons: spring, summer, autumn and winter

For details on how to modify the above files and what the parameters in each file mean, you can find a detailed introduction in the Openharmomy documentation, including internal structure descriptions and configuration examples.

Compile the entire source code, and burn the compiled file into BearPi-HM Micro as in the previous article

After the burning is completed, open the serial port assistant. Through the serial port assistant, you can use most of the Linux operating commands

Run the program we compiled and view the serial port output

./bin/helloworld

Successfully printed the contents of the source file

Throughout the whole process, I found that I had to deal with components quite often. OpenHarmony follows a layered design, which is divided into the kernel layer, system service layer, framework layer, and application layer from bottom to top. System functions are expanded step by step according to "system > subsystem > component". In the multi-device deployment scenario, it supports cutting out some unnecessary components according to actual needs. A subsystem is a logical concept, which is specifically composed of corresponding components.

A component is a reusable software unit that is a further decomposition of a subsystem. It contains source code, configuration files, resource files, and compilation scripts. It is a binary unit that can be independently built, integrated in binary form, and has independent verification capabilities.

Jacktang

It is true that the Openharmomy compilation framework and components have to deal with each other quite often.

lugl4313820

It seems that I need to learn how to compile seriously. I feel a little dizzy looking at it!

freebsder

It gives me a headache to see the engineering configuration of this kind of text.

数码小叶

freebsder posted on 2022-4-19 17:42 It gives me a headache to see this kind of text engineering configuration.

The advantage is that it is free and does not require an IDE

数码小叶

lugl4313820 posted on 2022-4-14 08:41 It seems that I have to learn how to compile seriously. I feel a little dizzy looking at it!

Openharmomy is not compatible with CMake

数码小叶

Jacktang posted on 2022-4-14 07:15 It is true that the number of times the Openharmomy compilation framework and components are dealt with is still quite large

There are so many rules to be familiar with.