OpenHarmony鸿蒙硬件-控制蜂鸣器播放声音-马育民老师

# 蜂鸣器介绍

https://www.malaoshi.top/show_1GW1wtTYVAmV.html

# 开发

### 步骤

1. 并初始化
2. 循环调用PwmStart、PwmStop方法
3. 配置模块构建脚本
4. 配置模块到应用子系统
5. 启用PWM功能（关键）

### 代码

创建文件 `beeper_demo.c`

代码如下：

```
#include <stdio.h>
#include <unistd.h>
#include "ohos_init.h"
#include "cmsis_os2.h"
#include "wifiiot_gpio.h"
#include "wifiiot_gpio_ex.h"
#include "wifiiot_pwm.h"
#include "hi_pwm.h"
void init(void)
{
    GpioInit();
    // 蜂鸣器引脚 设置为 PWM功能
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_9, WIFI_IOT_IO_FUNC_GPIO_9_PWM0_OUT);
    PwmInit(WIFI_IOT_PWM_PORT_PWM0);
}

void BeeperDemo(void)
{
    init();
    while (1)
    {
        uint16_t freqDivisor = 34052;
        //占空比，频率
        PwmStart(WIFI_IOT_PWM_PORT_PWM0, freqDivisor / 2, freqDivisor);
        usleep(2000000);
        PwmStop(WIFI_IOT_PWM_PORT_PWM0);
        usleep(1000000);
    } 
}
SYS_RUN(BeeperDemo);
```

### 代码解释

- GpioInit()：初始化GPIO设备，详见[链接](https://www.malaoshi.top/show_1GW1wH597h1w.html "链接")

- IoSetFunc(WIFI_IOT_IO_NAME_GPIO_9, WIFI_IOT_IO_FUNC_GPIO_9_PWM0_OUT)：设置GPIO 9引脚功能，详见[链接](https://www.malaoshi.top/show_1GW1wHTm3p6I.html "链接")

- WIFI_IOT_IO_NAME_GPIO_9：详见[链接](https://www.malaoshi.top/show_1GW1wHKNXl2a.html "链接")
 - WIFI_IOT_IO_FUNC_GPIO_9_PWM0_OUT：详见[链接](https://www.malaoshi.top/show_1GW1wHSaFlvB.html "链接")

- PwmInit(WIFI_IOT_PWM_PORT_PWM0)：详见[链接](https://www.malaoshi.top/show_1GW1wvGSGDmz.html "链接")

- WIFI_IOT_PWM_PORT_PWM0：详见[链接](https://www.malaoshi.top/show_1GW1wuP89JXG.html "链接")

- PwmStart(WIFI_IOT_PWM_PORT_PWM0, freqDivisor / 2, freqDivisor)：详见[链接](https://www.malaoshi.top/show_1GW1x3wUy4B9.html "链接")

- usleep(1000 * 1000)：详见[链接](https://www.malaoshi.top/show_1GW1wJDkVcQB.html "链接")

- PwmStop(WIFI_IOT_PWM_PORT_PWM0)：详见[链接](https://www.malaoshi.top/show_1GW1wvdPezSb.html "链接")

# 编辑BUILD.gn文件

### 编辑1

在代码同级目录创建下面文件：

```
BUILD.gn
```

内容：

```
static_library("traffic_demo") { 
    sources = [ 
        # "led_demo.c" 
        # "traffic_light_demo.c" 
        "beeper_music_demo.c",
    ]
    include_dirs = [
        "//utils/native/lite/include",
        "//base/iot_hardware/interfaces/kits/wifiiot_lite",
        "//kernel/liteos_m/components/cmsis/2.0",
    ] 
}
```

### 编辑2

编辑下面文件：

```
\\applications\sample\wifi-iot\app\BUILD.gn
```

内容：

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

lite_component("app") {
    features = [
        "code_v2.0/std_03:hello_demo",
    ]
}

```

# 启用PWM功能

[OpenHarmony鸿蒙硬件-启用PWM功能（关键）](https://www.malaoshi.top/show_1GW1wuJn5Rze.html "OpenHarmony鸿蒙硬件-启用PWM功能（关键）")

# 编译代码

详见链接：
https://www.malaoshi.top/show_1GW1wTyUOMPk.html

原文出处：http://www.malaoshi.top/show_1GW1wtUGdpYZ.html