目录结构

先在./applications/sample/wifi-iot/app路径下新建一个目录（或一套目录结构），用于存放业务源码文件。
本例程：在app下新增业务led，其中hello_world.c为业务代码，BUILD.gn为编译脚本，具体规划目录结构如下：

.
└── applications
    └── sample
        └── wifi-iot
            └── app
                │── led
                │  │── led.c
                │  └── BUILD.gn
                └── BUILD.gn

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业务代码。

新建./applications/sample/wifi-iot/app/led下的led.c文件，在led.c中新建业务入口函数led，并实现业务逻辑。并在代码最下方，使用HarmonyOS启动恢复模块接口SYS_RUN()启动业务。（SYS_RUN定义在ohos_init.h文件中）

BUILD.gn为编译脚本
led.c为业务逻辑代码所在文件

led.c


#include <stdio.h>
#include <unistd.h>
#include "ohos_init.h"
#include "cmsis_os2.h"
#include "wifiiot_gpio.h"
#include "wifiiot_gpio_ex.h"

#define LED_ON_TIME_US 2000000
#define LED_OFF_TIME_US 1000000

static void Led(void)
{
    //GPIO引脚初始化
    GpioInit();
    //设置管脚功能为GPIO
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_9, WIFI_IOT_IO_FUNC_GPIO_9_GPIO);
    //设置GPIO引脚方向为输出
    GpioSetDir(WIFI_IOT_IO_NAME_GPIO_9, WIFI_IOT_GPIO_DIR_OUT);
    while (1) {
        //设置GPIO09输出为低电平
        GpioSetOutputVal(WIFI_IOT_IO_NAME_GPIO_9, 0);
        //打印输出日志
        printf("[DEMO] LED on.\n");
        //延时一定时间，即亮灯的持续时间
        usleep(LED_ON_TIME_US);
        //设置GPIO09输出为高电平
        GpioSetOutputVal(WIFI_IOT_IO_NAME_GPIO_9, 1);
        //打印输出日志
        printf("[DEMO] LED off.\n");
        //延时一定时间，即灭灯的持续时间
        usleep(LED_OFF_TIME_US);
    }
}
SYS_RUN(Led);




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BUILD.gn（app/BUILD.gn）

static_library("bahuyang") {
    sources = [
        "led.c"
    ]

    include_dirs = [
        "//utils/native/lite/include",
        "//kernel/liteos_m/components/cmsis/2.0",
        "//base/iot_hardware/interfaces/kits/wifiiot_lite",
    ]
}

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“bahuyang”:是生成静态库名称，可随意更改
“led.c”：代码文件

BUILD.gn（）

# Copyright (c) 2020 Huawei Device Co., Ltd.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

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

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

lite_component("app") {
    features = [
        #"startup",
        "led:bahuyang"
    ]
}


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将”startup”注释，运行我们自己的文件
“led”:工程目录
bahuyang:静态库文件