ESP32用SDK创建用LED PWM控制器实现的RGB七彩渐变程序

以下是ESP32用SDK创建用LED PWM控制器实现的RGB七彩渐变程序的示例代码：

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "driver/ledc.h"

#define RED_PIN 25
#define GREEN_PIN 26
#define BLUE_PIN 27

#define LEDC_CH_NUM 3
#define LEDC_FREQ_HZ 5000
#define LEDC_RESOLUTION 8

void led_pwm_init()
{
    ledc_timer_config_t timer_conf;
    timer_conf.duty_resolution = LEDC_RESOLUTION;
    timer_conf.freq_hz = LEDC_FREQ_HZ;
    timer_conf.speed_mode = LEDC_HIGH_SPEED_MODE;
    timer_conf.timer_num = LEDC_TIMER_0;
    ledc_timer_config(&timer_conf);

    ledc_channel_config_t ch_conf[LEDC_CH_NUM];
    ch_conf[0].channel = LEDC_CHANNEL_0;
    ch_conf[0].duty = 0;
    ch_conf[0].gpio_num = RED_PIN;
    ch_conf[0].speed_mode = LEDC_HIGH_SPEED_MODE;
    ch_conf[0].timer_sel = LEDC_TIMER_0;
    ch_conf[1].channel = LEDC_CHANNEL_1;
    ch_conf[1].duty = 0;
    ch_conf[1].gpio_num = GREEN_PIN;
    ch_conf[1].speed_mode = LEDC_HIGH_SPEED_MODE;
    ch_conf[1].timer_sel = LEDC_TIMER_0;
    ch_conf[2].channel = LEDC_CHANNEL_2;
    ch_conf[2].duty = 0;
    ch_conf[2].gpio_num = BLUE_PIN;
    ch_conf[2].speed_mode = LEDC_HIGH_SPEED_MODE;
    ch_conf[2].timer_sel = LEDC_TIMER_0;
    for (int i = 0; i < LEDC_CH_NUM; i++) {
        ledc_channel_config(&ch_conf[i]);
    }
}

void rgb_fade()
{
    int step = 5;
    int r = 255, g = 0, b = 0;
    while (1) {
        for (int i = 0; i < 51; i++) {
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0, r);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0);
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_1, g);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_1);
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_2, b);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_2);
            vTaskDelay(20 / portTICK_PERIOD_MS);
            r -= step;
            g += step;
        }
        for (int i = 0; i < 51; i++) {
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0, r);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0);
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_1, g);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_1);
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_2, b);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_2);
            vTaskDelay(20 / portTICK_PERIOD_MS);
            g -= step;
            b += step;
        }
        for (int i = 0; i < 51; i++) {
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0, r);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_0);
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_1, g);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_1);
            ledc_set_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_2, b);
            ledc_update_duty(LEDC_HIGH_SPEED_MODE, LEDC_CHANNEL_2);
            vTaskDelay(20 / portTICK_PERIOD_MS);
            r += step;
            b -= step;
        }
    }
}

void app_main()
{
    led_pwm_init();
    xTaskCreate(rgb_fade, "rgb_fade", 2048, NULL, 5, NULL);
}

这个程序实现了一个RGB七彩渐变效果。首先，我们使用`led_pwm_init()`函数初始化三个LED PWM通道，分别对应红、绿、蓝三个颜色。然后，我们使用`rgb_fade()`函数实现RGB七彩渐变效果。在这个函数中，我们使用三个变量`r`、`g`、`b`来代表红、绿、蓝三个颜色的亮度，使用`step`变量代表每次变化的步长。在每次循环中，我们先对红色进行减少、绿色进行增加，然后对绿色进行减少、蓝色进行增加，最后对红色进行增加、蓝色进行减少，这样就实现了一个RGB七彩渐变效果。在每次变化后，我们使用`ledc_set_duty()`函数和`ledc_update_duty()`函数来更新三个LED PWM通道的亮度，然后使用`vTaskDelay()`函数来等待一段时间，以实现比较平滑的变化效果。最后，我们在`app_main()`函数中创建一个任务来运行`rgb_fade()`函数。