一、准备工作
二、编译代码
三、测试

9.PWM输出测试

该教程演示如何通过开发板的GPIO输出PWM波

一、准备工作

准备1块BearPi-Pico H2821开发板

二、编译代码

在Windows下编译操作

点击左侧的“KConfig”,打开配置界面.

选择Support PWM Sample

Application  --->
    [*] Enable Sample.
    [*]     Enable the Sample of peripheral.
    [ ]         Enable all the sample of peripheral, it's just for build.
    [ ]         Support ADC Sample.
    [ ]         Support BLINKY Sample.
    [ ]         Support BUTTON Sample.
    [ ]         Support DMA Sample.
    [ ]         Support I2C Sample.
    [ ]         Support I2S Sample.
    [ ]         Support KEYSCAN Sample.
    [ ]         Support PINCTRL Sample.
    [*]         Support PWM Sample.
                    PWM Sample Configuration  --->

设置PWM输出的GPIO，这边以设置板载LED连接的GPIO31为例。
```
PWM Sample Configuration  --->
    (31) Choose PWM pin.
```
按下"Save"键保存配置。
可在代码中修改高低电平时间，已达到输出不同占空比的PWM波
编译烧录固件
参考环境搭建教程编译烧录代码

在Ubuntu下编译操作

在MobaXterm中输入:
```
./build.py menuconfig
```

选择Support PWM Sample

Application  --->
    [*] Enable Sample.
    [*]     Enable the Sample of peripheral.
    [ ]         Enable all the sample of peripheral, it's just for build.
    [ ]         Support ADC Sample.
    [ ]         Support BLINKY Sample.
    [ ]         Support BUTTON Sample.
    [ ]         Support DMA Sample.
    [ ]         Support I2C Sample.
    [ ]         Support I2S Sample.
    [ ]         Support KEYSCAN Sample.
    [ ]         Support PINCTRL Sample.
    [*]         Support PWM Sample.
                    PWM Sample Configuration  --->

设置PWM输出的GPIO，这边以设置板载LED连接的GPIO31为例。
```
PWM Sample Configuration  --->
    (31) Choose PWM pin.
```
按下"ESC"键退出并保存配置。
可在代码中修改高低电平时间，已达到输出不同占空比的PWM波
编译烧录固件
参考环境搭建教程编译烧录代码

三、测试

烧录固件后按下开发的复位按键，用示波器或者逻辑分析查看PWM输出引脚的PWM波，或者通过改变不同的占空比，观察开发板上的LED灯的亮度变化。