RT-Thread-<内核学习营>+坦然+探索者stm32f407板子RT-thread的pwm点灯实验RT-Thread问答社区

<内核学习营>+坦然+探索者stm32f407板子RT-thread的pwm点灯实验

发布于 2018-09-07 19:39:50 浏览：2467 订阅该版

* 本帖最后由 luzixing 于 2018-9-12 11:41 编辑 *

实验要求：本实验是在探索者开发板完成的
硬件：至少有一路带PWM输出功能的GPIO， 能够用来连接LED 灯有一路串口用来做msh shell 终端
软件：
串口驱动
PIN 驱动
PWM 驱动

准备工作：配置开发板LED 灯连接的PIN 号。

实现的代码（rgb_pwm）：

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

#define   PERIOD   255
#define   CH_R     1

extern rt_err_t rt_pwm_enable(int channel);
extern rt_err_t rt_pwm_set(int channel, rt_uint32_t period, rt_uint32_t pulse);

void rt_pwm_rgb_entry(void* parameter)
{
    rt_uint8_t random;

/*使能各通道*/
    rt_pwm_enable(CH_R);
        
    while(1)
    {
        random = rand()%255;    /*产生一个伪随机数*/
        rt_pwm_set(CH_R, PERIOD, random);   /*用产生的伪随机数决定pwm波的占空比*/
        
        rt_thread_delay(500);
    }
}

int rt_pwm_rgb_init()
{
        rt_device_t pwm_dev;
        rt_thread_t tid;
        
        pwm_dev = rt_device_find("pwm");

if(NULL != pwm_dev)
        {
                
        tid = rt_thread_create("pwm_led",
            rt_pwm_rgb_entry, RT_NULL,
            512, RT_THREAD_PRIORITY_MAX/3, 20);

if (tid != RT_NULL)
            rt_thread_startup(tid);
        }

return 0;
}
MSH_CMD_EXPORT(rt_pwm_rgb_init, rgb by pwm.);

实现的代码（pwm_breathe）：
#include <rtthread.h>
#include <rtdevice.h>

#define     PERIOD  512
#define     CH_R    1

/* LED亮度等级 PWM表,指数曲线 */
/*此表使用工程目录下的python脚本index_wave.py生成*/
uint16_t indexWave[] = {
  1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2,
        2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 
        6, 6, 7, 7, 8, 8, 9, 9, 10, 11, 12, 
        12, 13, 14, 15, 17, 18, 19, 20, 22, 
        23, 25, 27, 29, 31, 33, 36, 38, 41, 
        44, 47, 51, 54, 58, 63, 67, 72, 77, 
        83, 89, 95, 102, 110, 117, 126, 135,
        145, 156, 167, 179, 192, 206, 221, 237, 
        254, 272, 292, 313, 336, 361, 387, 415, 
        445, 477, 512, 512, 477, 445, 415, 387, 
        361, 336, 313, 292, 272, 254, 237, 221, 
        206, 192, 179, 167, 156, 145, 135, 126, 
        117, 110, 102, 95, 89, 83, 77, 72, 67, 63,
        58, 54, 51, 47, 44, 41, 38, 36, 33, 31, 29,
        27, 25, 23, 22, 20, 19, 18, 17, 15, 14, 13,
        12, 12, 11, 10, 9, 9, 8, 8, 7, 7, 6, 6, 5, 5,
        5, 4, 4, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2,
        2, 2, 1, 1, 1, 1, 1, 1
};

/*计算PWM表有多少个元素*/
rt_uint16_t POINT_NUM = sizeof(indexWave)/sizeof(indexWave[0]);

void rt_pwm_rgb_entry1(void* parameter)
{
    rt_uint16_t i = 0;
    
    /*使能各通道*/
    rt_pwm_enable(CH_R);
        
    while(1)
    {
        rt_pwm_set(CH_R, PERIOD, indexWave*);**

if(i >= POINT_NUM-1) i = 0;
        else i++;
        
        /* 设置使得整个呼吸过程为3秒左右即可达到很好的效果 */
        rt_thread_delay(3000/POINT_NUM);
    }
}

int rt_breathe_rgb_init()
{
        rt_device_t pwm_dev;
        rt_thread_t tid;
        
        pwm_dev = rt_device_find("pwm");
        if(NULL != pwm_dev)
        {
        tid = rt_thread_create("pwm_led",
            rt_pwm_rgb_entry1, RT_NULL,
            512, RT_THREAD_PRIORITY_MAX/3, 20);

if (tid != RT_NULL)
            rt_thread_startup(tid);
        }

return 0;
}
MSH_CMD_EXPORT(rt_breathe_rgb_init, rgb breathe by pwm.);

实验步骤：
一.移植pwm的驱动（主要是修改定时器的配置内容）
二.下载程序观察现象

结果：
![1535944921(1).jpg](/uploads/201809/07/192947bgfmxe661gm1flff.jpg)![1535945233(1).jpg](/uploads/201809/07/192948jxmt6tuap6epk6k6.jpg)![641255343125324459.jpg](/uploads/201809/07/192948x4sj6jhcs7p6vjz6.jpg)![692083768642143411.jpg](/uploads/201809/07/192948pd4uap2ppa1ala46.jpg)![704914546303421744.jpg](/uploads/201809/07/192948tu3a9g3a9xbxuub3.jpg)

遇到的问题：下载程序后，只是串口可以打印，但是不能够点亮led灯

解决方法：对移植的驱动仔细的从头看了一遍，发现没有配置定时器的输出模式，配置好输出模式就可以解决了。