10 连续使用 rt_pwm_set调整周期时会产生杂波如何解决

发布于 2024-05-16 16:41:57 浏览：287 订阅该版

小弟在线程中每隔50ms绝对值使用rt_pwm_set()调整一次pwm的周期，发现会有很明显的杂波。把间隔时间从50ms调整为500ms后确认确实是切换周期引起的杂波，之前用io口采用延时拉高拉低的方式没有这个杂波。有没有遇到同样问题的大佬们给个建议！
1.以下是线程初始化代码
```c
    rt_thread_t tens_thread = rt_thread_create("tens_th", tens_thread_entry, RT_NULL, 512, 25, 5);
    if (tens_thread != RT_NULL)
    {
        rt_thread_startup(tens_thread);
    }
```
2.以下是数组和线程内部代码

```c
rt_uint32_t period_form[200] = {5000000, 5070507, 5142009, 5214519, 5288051, 5362621, 5438241, 5514929, 5592697, 5671563, 5751540, 5832645, 5914894, 5998303, 6082888, 6168665, 6255653, 6343867, 6433324, 6524044, 6616042, 6709338, 6803950, 6899896, 6997194, 7095865, 7195927, 7297401, 7400305, 7504660, 7610487, 7717806, 7826638, 7937005, 8048929, 8162430, 8277533, 8394258, 8512630, 8632670, 8754404, 8877854, 9003044, 9130001, 9258747, 9389309, 9521712, 9655982, 9792146, 9930230, 10070261, 10212266, 10356274, 10502313, 10650411, 10800597, 10952902, 11107354, 11263984, 11422823, 11583901, 11747251, 11912905, 12080894, 12251253, 12424014, 12599210, 12776878, 12957051, 13139764, 13325054, 13512957, 13703510, 13896750, 14092714, 14291442, 14492973, 14697345, 14904599, 15114776, 15327917, 15544063, 15763257, 15985542, 16210962, 16439560, 16671382, 16906473, 17144880, 17386648, 17631825, 17880460, 18132601, 18388297, 18647599, 18910558, 19177225, 19447652, 19721892, 20000000, 20000000, 19721892, 19447652, 19177225, 18910558, 18647599, 18388297, 18132601, 17880460, 17631825, 17386648, 17144880, 16906473, 16671382, 16439560,
16210962, 15985542, 15763257, 15544063, 15327917, 15114776, 14904599, 14697345, 14492973, 14291442, 14092714, 13896750, 13703510, 13512957, 13325054, 13139764, 12957051, 12776878, 12599210, 12424014, 12251253, 12080894, 11912905, 11747251, 11583901, 11422823, 11263984, 11107354, 10952902, 10800597, 10650411, 10502313, 10356274, 10212266, 10070261, 9930230, 9792146, 9655982, 9521712, 9389309, 9258747, 9130001, 9003044, 8877854, 8754404, 8632670, 8512630, 8394258, 8277533, 8162430, 8048929, 7937005, 7826638, 7717806, 7610487, 7504660, 7400305, 7297401, 7195927, 7095865, 6997194, 6899896, 6803950, 6709338, 6616042, 6524044, 6433324, 6343867, 6255653, 6168665, 6082888, 5998303, 5914894, 5832645, 5751540, 5671563, 5592697, 5514929, 5438241, 5362621, 5288051, 5214519, 5142009, 5070507, 5000000};
```
```c
static void tens_thread_entry(void *parameter)
{
    rt_tick_t ms;
    rt_uint8_t period_index=0;
    while(1)
    {
        rt_pwm_set(pwm4_dev, RH, (period_form[period_index]), 100000);
        period_index++;
        if(period_index>=199)
        {
            period_index = 0;
        }
        ms = rt_tick_get();
        rt_thread_delay_until(&ms, 500);
    }
}
```

![微信图片_20240516164129.jpg](https://oss-club.rt-thread.org/uploads/20240516/999a23eae395b24b29fabe8e59aa68a4.jpg.webp)