introduction

This article through a very simple program , It shows in the little bear sect BearPi-HM_Micro_Small The complete process of Hongmeng equipment development on the development board ： Download the source code 、 Create a project 、 Write the source program 、 To write / Modify the compilation script 、 compile 、 burning 、 test .

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Tips ： Please follow 《 Build little bear pie BearPi-HM_Micro_Small Pure Ubuntu development environment 》 Build a good development environment .

This article refers to the little bear School BearPi-HM_Micro_Small Some tutorials of development board .

https://gitee.com/bearpi/bearpi-hm_micro_small

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One 、 Download the source code

1、 If not installed git, Reference first 《git And gitee Quick start 》 The second part , install git.

2、 Execute the following command in the directory where you want to place the source code of Xiaoxiong pie Hongmeng , Download the source code .

git clone https://gitee.com/bearpi/bearpi-hm_micro_small.git

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Two 、 Create a project

1、 open DevEco Device Tool.（1） Click... In the left toolbar DevEco Icon ;（2） single click Projects;（3） single click Import Project Button ;（4） In the pop-up window , Select the folder Projects;（5） Select project bearpi-hm_micro_small;（6） single click Import Button .

2、 In the window shown below , single click Import.

3、 In the window shown below , choice Import from OpenHarmony Source.

4、 After setting according to the following figure , single click Open.

5、 In the window shown below , choice Current Window, Open the project .

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3、 ... and 、 Write the source program

1、 In path applications/BearPi/BearPi-HM_Micro/samples Next, create a new folder ：dandelion.

2、 In the folder dandelion Next, create a new folder ：hello_world.

3、 In the folder hello_world Next create a new file ：hello_world.c, Write the source program in this file ：

#include <stdio.h>

int main(int argc, char **argv)
{
    printf("\n************************************************\n");
    printf("\n\t\tHello BearPi!\n");
    printf("\n************************************************\n\n");
    
    return 0;
}

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Four 、 To write / Modify the compilation script

1、 In the folder hello_world Next create a new file ：BUILD.gn, Write the source program in this file hello_world.c Compiled script for ：

executable("hello_world_exe") {
    output_name = "hello_world"
    sources = [ "hello_world.c" ]
    include_dirs = []
    defines = []
    cflags_c = []
    ldflags = []
}

executable("hello_world_exe")： Instructs the compiler to build the subsystem to complete a task named hello_world_exe Build build build “ Small target ”.executable This is it “ Small target ” type ; This “ Small target ” Specific content of ： take sources Source files in the list （ That is to say hello_world.c） Compile into an executable , The name of the generated executable file is output_name Appoint , That is to say hello_world.

2、 In the folder dandelion Next create a new file ：BUILD.gn.

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

lite_component("dandelion_app") {
    features = [
        "hello_world:hello_world_exe",
    ]
}

lite_component("dandelion_app")： Instructs the compiler to build the subsystem to complete a type of lite_component Of 、 be known as dandelion_app Compile build target .

lite_component This type is in lite_component.gni Defined , Used to instruct the compile build subsystem to compile and build a component （Component）.

at present , stay dandelion_app This compilation build target only contains hello_world Compilation build in directory “ Small target ” hello_world_exe. in other words , The components to be built here （Component） Contains only one executable program ：hello_world. As for the name of this component , Is in the next file applications.json Specified in the .

3、 Open the path build/lite/components Subsystem under applications Configuration file for applications.json, Add the components that you want to compile and build to the subsystem applications In the component list of .

        {
          "component": "bearpi_dandelion_app",
          "description": "app written by dandelion",
          "optional": "true",
          "dirs": [
            "applications/BearPi/BearPi-HM_Micro/samples/dandelion"
          ],
          "targets": [
            "//applications/BearPi/BearPi-HM_Micro/samples/dandelion:dandelion_app"
          ],
          "rom": "",
          "ram": "",
          "output": [],
          "adapted_kernel": [ "liteos_a" ],
          "features": [],
          "deps": {
            "components": [],
            "third_party": []
          }
        },

4、 Open the path vendor/bearpi/bearpi_hm_micro Products under bearpi_hm_micro Configuration file for config.json, The components to be built before will be compiled bearpi_dandelion_app Add to subsystem applications In the component list of .

      {
        "subsystem": "applications",
        "components": [
           { "component": "bearpi_dandelion_app", "features":[] },
           { "component": "bearpi_sample_app", "features":[] },
           { "component": "bearpi_screensaver_app", "features":[] },
           { "component": "bearpi_sample_communication", "features":[] }
        ]
      },

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5、 ... and 、 compile

1、 Choose products . Execute the following command at the root of the project ：

hb set

As shown in the figure above , There is only one product option , So just go straight back .

2、 compile . Execute the following command at the root of the project ：

hb build -t notest --tee -f

wait for , Until the terminal appears as shown in the figure below build success word , The compilation is successful .

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6、 ... and 、 burning

1、 Copy the image

After compilation , The generated image file is in the directory ：out/bearpi_hm_micro/bearpi_hm_micro in , Put three image files ：OHOS_Image.stm32、rootfs_vfat.img and userfs_vfat.img Copy to directory ：applications/BearPi/BearPi-HM_Micro/tools/download_img/kernel in .

cp out/bearpi_hm_micro/bearpi_hm_micro/OHOS_Image.stm32 applications/BearPi/BearPi-HM_Micro/tools/download_img/kernel/
cp out/bearpi_hm_micro/bearpi_hm_micro/rootfs_vfat.img applications/BearPi/BearPi-HM_Micro/tools/download_img/kernel/
cp out/bearpi_hm_micro/bearpi_hm_micro/userfs_vfat.img applications/BearPi/BearPi-HM_Micro/tools/download_img/kernel/

2、 use USB The line connects the development board Ubuntu virtual machine .

3、 Turn the dial switch of the development board to “000” Burn mode , And click on the development board RESET Key .

4、 Double-click to open STM32CubeProgrammer; Select the interface type ：USB; Click the refresh button ; single click Connect Connect the development board .

5、 After connecting , single click Open file; Select the burning configuration under the project directory tvs file , single click Open.

6、 Click on Browse Button , Then select the burning image path under the project source code , single click Open

7、 Click on Download Button to start image burning , And wait for the burning to complete .

8、 After burning , In the pop-up window, click OK; close STM32CubeProgrammer.

9、 Click on DevEco Device Tool In the toolbar on the left DevEco Icon , stay “PROJECT TASKS”– Hongmeng project bearpi-hm_micro_small Next , single click Monitor Button , Open the serial terminal .

The terminal window is shown in the figure below ：

10、 Turn the dial switch of the development board to “010”emmc Boot mode , And click on the development board “RESET” Button reset development board , The development board starts .

Print the startup log information in the serial port terminal .

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7、 ... and 、 test

Input instructions in the serial port terminal ：./bin/hello_world, And then go back , The results shown in the following figure will be displayed in the serial port terminal ：

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