feat: support ws2812 simple encode

Author: YanKE01

build_config.yml

@@ -99,6 +99,14 @@ projects:
     idf_version: release-v5.4
     target: esp32s3
 
+  - path: examples/peripherals/rmt/rmt_simple_tx
+    idf_version: release-v5.4
+    target: esp32s3
+
+  - path: examples/peripherals/rmt/ws2812_simple_encoder
+    idf_version: release-v5.4
+    target: esp32s3
+
   - path: examples/peripherals/spi/spi_basic
     idf_version: release-v5.4
     target: esp32s3

examples/peripherals/rmt/rmt_simple_tx/main/main.c

@@ -19,20 +19,20 @@ void app_main(void)
 
     rmt_encoder_handle_t bytes_encoder = NULL;
 
-    // 对bit 0和1 进行编码
+    // Encode bit 0 and 1
     rmt_bytes_encoder_config_t bytes_enc_config = {
         .bit0 = {
             .level0 = 1,
             .duration0 = 1, // 1us
             .level1 = 0,
             .duration1 = 1, // 1us
-        }, // 对于 0 而言，先高电平持续1us，在低电平持续1us
+        }, // For bit 0: first high level for 1us, then low level for 1us
         .bit1 = {
             .level0 = 1,
             .duration0 = 9, // 9us
             .level1 = 0,
             .duration1 = 3, // 3us
-        }, // 对于 1 而言，先高电平持续 9us，在低电平持续3us
+        }, // For bit 1: first high level for 9us, then low level for 3us
     };
 
     rmt_new_bytes_encoder(&bytes_enc_config, &bytes_encoder);
@@ -45,7 +45,7 @@ void app_main(void)
     while (1) {
         rmt_transmit(tx_channel, bytes_encoder, (uint8_t[]) {
             0x05
-        }, 1, &transmit_config); // 对于0x05，其实是8bit的数据，对应 0000 0101
+        }, 1, &transmit_config); // For 0x05, it's actually 8-bit data, corresponding to 0000 0101
         vTaskDelay(500 / portTICK_PERIOD_MS);
     }
 }

examples/peripherals/rmt/rmt_simple_tx/sdkconfig.defaults

@@ -0,0 +1,4 @@
+CONFIG_IDF_TARGET="esp32s3"
+CONFIG_IDF_TARGET_ESP32S3=y
+
+CONFIG_ESP32S3_DEFAULT_CPU_FREQ_240=y

examples/peripherals/rmt/ws2812_simple_encoder/CMakeLists.txt

@@ -0,0 +1,8 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(ws2812_simple_encoder)

examples/peripherals/rmt/ws2812_simple_encoder/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "main.c"
+                    INCLUDE_DIRS ".")

examples/peripherals/rmt/ws2812_simple_encoder/main/main.c

@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "driver/rmt_tx.h"
+#include "esp_log.h"
+
+static const char *TAG = "WS2812";
+
+static const rmt_symbol_word_t ws2812_zero = {
+    .level0 = 1,
+    .duration0 = 4, /*!< 0.4us */
+    .level1 = 0,
+    .duration1 = 9, /*!< 0.9us */
+};
+
+static const rmt_symbol_word_t ws2812_one = {
+    .level0 = 1,
+    .duration0 = 9, /*!< 0.9us */
+    .level1 = 0,
+    .duration1 = 3, /*!< 0.4us */
+};
+
+static const rmt_symbol_word_t ws2812_reset = {
+    .level0 = 0,
+    .duration0 = 250, /*!< 25us */
+    .level1 = 0,
+    .duration1 = 250, /*!< 25us */
+};
+
+static size_t encoder_callback(const void *data, size_t data_size,
+                               size_t symbols_written, size_t symbols_free,
+                               rmt_symbol_word_t *symbols, bool *done, void *arg)
+{
+    if (symbols_free < 8) {
+        return 0; /*!< Need at least 8 symbols to form one byte */
+    }
+    printf("symbols_written:%d,data_size:%d\n", symbols_written, data_size);
+
+    size_t data_pos = symbols_written / 8; /*!< Calculate current byte position, assuming input is {0xFF, 0x00, 0x00}, data_size is 3, each byte written increments symbols_written by 8 */
+    uint8_t *data_bytes = (uint8_t *)data;
+
+    if (data_pos < data_size) {
+        size_t symbol_pos = 0;
+        for (int bitmask = 0x80; bitmask != 0; bitmask >>= 1) {
+            if (data_bytes[data_pos] & bitmask) {
+                symbols[symbol_pos++] = ws2812_one;
+            } else {
+                symbols[symbol_pos++] = ws2812_zero;
+            }
+        }
+
+        return symbol_pos;
+    } else {
+        symbols[0] = ws2812_reset;
+        *done = 1;
+        return 1;
+    }
+}
+
+void app_main(void)
+{
+    rmt_channel_handle_t led_chan = NULL;
+    rmt_tx_channel_config_t tx_chan_config = {
+        .mem_block_symbols = 64,
+        .clk_src = RMT_CLK_SRC_DEFAULT,
+        .resolution_hz = 10 * 1000 * 1000, // 10MHz, 1 tick = 0.1us
+        .trans_queue_depth = 4,
+        .gpio_num = GPIO_NUM_38,
+        .intr_priority = 3
+    };
+
+    ESP_ERROR_CHECK(rmt_new_tx_channel(&tx_chan_config, &led_chan));
+
+    ESP_LOGI(TAG, "Create simple callback-based encoder");
+    rmt_encoder_handle_t simple_encoder = NULL;
+    const rmt_simple_encoder_config_t simple_encoder_cfg = {
+        .callback = encoder_callback
+        // Note we don't set min_chunk_size here as the default of 64 is good enough.
+    };
+    ESP_ERROR_CHECK(rmt_new_simple_encoder(&simple_encoder_cfg, &simple_encoder));
+
+    ESP_LOGI(TAG, "Enable RMT TX channel");
+    ESP_ERROR_CHECK(rmt_enable(led_chan));
+
+    ESP_LOGI(TAG, "Start LED rainbow chase");
+    rmt_transmit_config_t tx_config = {
+        .loop_count = 0, // no transfer loop
+    };
+
+    // WS2812 encoding is GRB
+    uint8_t red[3] = {0x00, 0xFF, 0x00}; /*!< R */
+    rmt_transmit(led_chan, simple_encoder, red, sizeof(red), &tx_config);
+    vTaskDelay(1000 / portTICK_PERIOD_MS);
+
+    uint8_t green[3] = {0xFF, 0x00, 0x00}; /*!< G */
+    rmt_transmit(led_chan, simple_encoder, green, sizeof(green), &tx_config);
+    vTaskDelay(1000 / portTICK_PERIOD_MS);
+
+    uint8_t blue[3] = {0x00, 0x00, 0xFF}; /*!< B */
+    rmt_transmit(led_chan, simple_encoder, blue, sizeof(blue), &tx_config);
+}

examples/peripherals/rmt/ws2812_simple_encoder/sdkconfig.defaults

@@ -0,0 +1,4 @@
+CONFIG_IDF_TARGET="esp32s3"
+CONFIG_IDF_TARGET_ESP32S3=y
+
+CONFIG_ESP32S3_DEFAULT_CPU_FREQ_240=y