RT-Thread-使用rt_thread无法输出PWM，但使用裸机程序则可以正常输出！RT-Thread问答社区

10 使用rt_thread无法输出PWM，但使用裸机程序则可以正常输出！

发布于 2024-12-17 13:32:02 浏览：42 订阅该版

[tocm]

## 背景: 
实际无法输出PWM波 但是打印报文PWM脉冲 脉宽的变化和线程程序都是正常执行的
使用的RTT 4.03版本；
单片机为STM32F103VET6；
输出引脚：PC9；
- PC9:TIM3_CH4;

根据此链接教程配置了cubeMX和rt_thread setting：
https://blog.csdn.net/m0_63474185/article/details/134096421

## 原理图
![PC9](https://oss-club.rt-thread.org/uploads/20241217/fb2c088d1a5272819436d6fc022e3998.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241217/f551ae106dd769ca317f9ef5fa24fce9.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241217/454504d90cf34d7d1c1da2933e96febe.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241217/570b948b495ba281d8dd661c54fc9435.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241217/5c0434ac78e4d7b0339e1aa8b50c9ce7.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241217/7477ca4b3fa90ff9f654157377340dcc.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20241217/e5ebd8c8e1a65d838168575746f80072.png)

**下方附完整代码  展开查看全部**
```c
/*
 * Copyright (c) 2006-2024, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2024-12-17     RT-Thread    first version
 */

#include <rtthread.h>
#include <rtdevice.h>
#include <board.h>

#define DBG_TAG "main"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>

#define LED_2  GET_PIN(C, 8)
int main(void)
{
    rt_pin_mode(LED_2, PIN_MODE_OUTPUT);
    rt_pin_write(LED_2, 1);
    int count = 1;

while (count++)
    {
        rt_pin_write(LED_2, 1);
        rt_thread_mdelay(1000);
        rt_pin_write(LED_2, 0);
        rt_thread_mdelay(1000);
    }

return RT_EOK;
}

#define PWM_DEV_NAME            "pwm3"  /* PWM设备名称 */
#define PWM_DEV_CHANNEL         4       /* PWM通道 */
#define THREAD_PRIORITY         9      /* 线程优先级 */
#define THREAD_STACK_SIZE       512     /* 线程栈大小 */
#define THREAD_TIMESLICE        10       /* 线程时间片大小 */

static rt_thread_t tid1 = RT_NULL;      /* 线程句柄 */
struct rt_device_pwm *pwm_dev;          /* PWM设备句柄 */
static rt_uint32_t period = 500000;     /* 周期为0.5ms，单位为纳秒ns */
static rt_uint32_t pulse =  250000;           /* PWM脉冲宽度值的增减方向 */

/* 线程 pwm_entry 的入口函数 */
static void pwm_entry(void *parameter)
{
    int i = 0;

while (1)
    {

rt_thread_mdelay(50);
        if(i == 0)
        {
            pulse += 50000;
            if(pulse >= period){
                i = 1;
            }
        }else {

pulse -= 50000;
            if(pulse <= 0){
                i = 0;
            }
        }
        rt_pwm_set(pwm_dev, PWM_DEV_CHANNEL, period, pulse);
        rt_kprintf("%d %d \n", period, pulse);
    }
    /* step 3、如果不再使用该通道，可以关闭 PWM 通道的输出 */
    rt_pwm_disable(pwm_dev, PWM_DEV_CHANNEL);
}

static int pwm_test(int argc, char *argv[])
{
    /* step 1.1、查找 PWM 设备 */
    pwm_dev = (struct rt_device_pwm *)rt_device_find(PWM_DEV_NAME);
    if (pwm_dev == RT_NULL)
    {
        rt_kprintf("pwm sample run failed! can't find %s device!\n", PWM_DEV_NAME);
        return RT_ERROR;
    }

/* step 1.2、设置 PWM 周期和脉冲宽度默认值 */
    rt_pwm_set(pwm_dev, PWM_DEV_CHANNEL, period, pulse);
    /* step 1.3、使能 PWM 设备的输出通道 */
    rt_pwm_enable(pwm_dev, PWM_DEV_CHANNEL);

/* 创建线程，名称是 pwm_thread ，入口是 pwm_entry*/
    tid1 = rt_thread_create("pwm_thread",
                             pwm_entry,
                             RT_NULL,
                             THREAD_STACK_SIZE,
                             THREAD_PRIORITY,
                             THREAD_TIMESLICE);

/* 如果获得线程控制块，启动这个线程 */
    if (tid1 != RT_NULL)
        rt_thread_startup(tid1);

return RT_EOK;
}
/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(pwm_test, pwm sample);
```

也尝试过使用别的引脚 ![PD15.png](https://oss-club.rt-thread.org/uploads/20241217/d1195b8495334806e28c972151123881.png)
配置了TM4_CH4也不能实际输出pwm但是用Keil逻辑程序则可以正常输出