Add rmtled: direct RMT WS2812 driver via ESP-IDF API

src/main.cpp

@@ -3,6 +3,7 @@
 
 #include <Arduino.h>
 #include <driver/gpio.h>
+#include <driver/rmt.h>
 #include <esp_rom_sys.h>
 #include "midi_transport.h"
 #include "pixel_stomp_mux.h"
@@ -124,6 +125,7 @@ void handle_serial_command(const String& cmd) {
         Serial.println("  pixel0/pixel1 - single pixel test");
         Serial.println("  gpiotest - raw GPIO pin diagnostic");
         Serial.println("  rawled   - bit-bang WS2812 (no library)");
+        Serial.println("  rmtled   - RMT WS2812 direct (ESP-IDF)");
         Serial.println("  anim     - re-run startup animation from loop");
     } else if (cmd == "anim") {
         Serial.println("[CMD] Running animation...");
@@ -139,6 +141,55 @@ void handle_serial_command(const String& cmd) {
         }
         mux.clear_all();
         Serial.println("[CMD] Animation done");
+    } else if (cmd == "rmtled") {
+        Serial.println("[CMD] RMT WS2812: pixel 0 = RED on GPIO 9");
+        uint8_t pin = 9;
+        uint8_t grb[] = {0x00, 0xFF, 0x00};
+        rmt_channel_t ch = RMT_CHANNEL_0;
+
+        rmt_config_t cfg = {
+            .rmt_mode = RMT_MODE_TX,
+            .channel = ch,
+            .gpio_num = (gpio_num_t)pin,
+            .clk_div = 8,
+            .mem_block_num = 1,
+            .flags = 0,
+            .tx_config = {
+                .carrier_freq_hz = 38000,
+                .carrier_level = RMT_CARRIER_LEVEL_HIGH,
+                .idle_level = RMT_IDLE_LEVEL_LOW,
+                .carrier_duty_percent = 33,
+                .carrier_en = false,
+                .loop_en = false,
+                .idle_output_en = true,
+            }
+        };
+        rmt_config(&cfg);
+        rmt_driver_install(ch, 0, 0);
+
+        rmt_item32_t items[25];
+        int idx = 0;
+        for (int b = 0; b < 3; b++) {
+            for (int bit = 7; bit >= 0; bit--) {
+                if (grb[b] & (1 << bit)) {
+                    items[idx].level0 = 1; items[idx].duration0 = 10;
+                    items[idx].level1 = 0; items[idx].duration1 = 10;
+                } else {
+                    items[idx].level0 = 1; items[idx].duration0 = 4;
+                    items[idx].level1 = 0; items[idx].duration1 = 12;
+                }
+                idx++;
+            }
+        }
+        items[idx].level0 = 0; items[idx].duration0 = 500;
+        items[idx].level1 = 0; items[idx].duration1 = 0;
+        idx++;
+
+        rmt_write_items(ch, items, idx, 1);
+        rmt_driver_uninstall(ch);
+        Serial.println("[CMD] RMT done. Wait 2 sec...");
+        delay(2000);
+        Serial.println("[CMD] Done");
     } else if (cmd == "rawled") {
         uint8_t pin = 9;
         Serial.println("[CMD] Bit-bang WS2812: pixel 0 = RED on GPIO 9");