1 /* RMT example -- RGB LED Strip
2
3 This example code is in the Public Domain (or CC0 licensed, at your option.)
4
5 Unless required by applicable law or agreed to in writing, this
6 software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
7 CONDITIONS OF ANY KIND, either express or implied.
8 */
9 #include "sdkconfig.h"
10 #include "freertos/FreeRTOS.h"
11 #include "freertos/task.h"
12 #include "esp_log.h"
13 #include "driver/rmt.h"
14 #include "led_strip.h"
15
16 static const char *TAG = "example";
17
18 #define RMT_TX_CHANNEL RMT_CHANNEL_0
19
20 #define EXAMPLE_CHASE_SPEED_MS (10)
21
22 /**
23 * @brief Simple helper function, converting HSV color space to RGB color space
24 *
25 * Wiki: https://en.wikipedia.org/wiki/HSL_and_HSV
26 *
27 */
led_strip_hsv2rgb(uint32_t h,uint32_t s,uint32_t v,uint32_t * r,uint32_t * g,uint32_t * b)28 void led_strip_hsv2rgb(uint32_t h, uint32_t s, uint32_t v, uint32_t *r, uint32_t *g, uint32_t *b)
29 {
30 h %= 360; // h -> [0,360]
31 uint32_t rgb_max = v * 2.55f;
32 uint32_t rgb_min = rgb_max * (100 - s) / 100.0f;
33
34 uint32_t i = h / 60;
35 uint32_t diff = h % 60;
36
37 // RGB adjustment amount by hue
38 uint32_t rgb_adj = (rgb_max - rgb_min) * diff / 60;
39
40 switch (i) {
41 case 0:
42 *r = rgb_max;
43 *g = rgb_min + rgb_adj;
44 *b = rgb_min;
45 break;
46 case 1:
47 *r = rgb_max - rgb_adj;
48 *g = rgb_max;
49 *b = rgb_min;
50 break;
51 case 2:
52 *r = rgb_min;
53 *g = rgb_max;
54 *b = rgb_min + rgb_adj;
55 break;
56 case 3:
57 *r = rgb_min;
58 *g = rgb_max - rgb_adj;
59 *b = rgb_max;
60 break;
61 case 4:
62 *r = rgb_min + rgb_adj;
63 *g = rgb_min;
64 *b = rgb_max;
65 break;
66 default:
67 *r = rgb_max;
68 *g = rgb_min;
69 *b = rgb_max - rgb_adj;
70 break;
71 }
72 }
73
app_main(void)74 void app_main(void)
75 {
76 uint32_t red = 0;
77 uint32_t green = 0;
78 uint32_t blue = 0;
79 uint16_t hue = 0;
80 uint16_t start_rgb = 0;
81
82 rmt_config_t config = RMT_DEFAULT_CONFIG_TX(CONFIG_EXAMPLE_RMT_TX_GPIO, RMT_TX_CHANNEL);
83 // set counter clock to 40MHz
84 config.clk_div = 2;
85
86 ESP_ERROR_CHECK(rmt_config(&config));
87 ESP_ERROR_CHECK(rmt_driver_install(config.channel, 0, 0));
88
89 // install ws2812 driver
90 led_strip_config_t strip_config = LED_STRIP_DEFAULT_CONFIG(CONFIG_EXAMPLE_STRIP_LED_NUMBER, (led_strip_dev_t)config.channel);
91 led_strip_t *strip = led_strip_new_rmt_ws2812(&strip_config);
92 if (!strip) {
93 ESP_LOGE(TAG, "install WS2812 driver failed");
94 }
95 // Clear LED strip (turn off all LEDs)
96 ESP_ERROR_CHECK(strip->clear(strip, 100));
97 // Show simple rainbow chasing pattern
98 ESP_LOGI(TAG, "LED Rainbow Chase Start");
99 while (true) {
100 for (int i = 0; i < 3; i++) {
101 for (int j = i; j < CONFIG_EXAMPLE_STRIP_LED_NUMBER; j += 3) {
102 // Build RGB values
103 hue = j * 360 / CONFIG_EXAMPLE_STRIP_LED_NUMBER + start_rgb;
104 led_strip_hsv2rgb(hue, 100, 100, &red, &green, &blue);
105 // Write RGB values to strip driver
106 ESP_ERROR_CHECK(strip->set_pixel(strip, j, red, green, blue));
107 }
108 // Flush RGB values to LEDs
109 ESP_ERROR_CHECK(strip->refresh(strip, 100));
110 vTaskDelay(pdMS_TO_TICKS(EXAMPLE_CHASE_SPEED_MS));
111 strip->clear(strip, 50);
112 vTaskDelay(pdMS_TO_TICKS(EXAMPLE_CHASE_SPEED_MS));
113 }
114 start_rgb += 60;
115 }
116 }
117
