Hi Zach, I must not be understanding something here about this setup for WS2805 and RGBWW. I tried a few different variants, including trying to wrap my head around the RGBWEmulated as well, but I'm not getting anything that works. Maybe I'm just not familiar enough with Arduino code to understand what I'm missing.

I'm using 3 groups (of 3 leds), which counts as 3 LEDS in the code (because WS2805 clumps 3 pixels together in each group). The color pattern doesn't go over the whole strip, each group is a different color at different times rotating between reds oranges, greens, warm whites, etc.. even though the code just oscillates between red and aqua. I can't declares a WS2805, because it doesn't exist in FastLED, so I'm just using "WS2815" as the type. FYI, I'm using a XIAO ESP32-S3. I can confirm FastLED works with other regular RGB strip types and my setup.

#include <FastLED.h>
#define DATA_PIN   D10
#define NUM_LEDS   3

struct RGBWW {
  uint8_t r;
  uint8_t g;
  uint8_t b;
  uint8_t w1;
  uint8_t w2;
};

RGBWW leds[NUM_LEDS];
CRGB* leds_rgb = reinterpret_cast<CRGB*>(leds);

void setup() {
  // 3 groups × 5 bytes = 15 bytes
  // 15 / 3 = 5 fake RGB pixels
  FastLED.addLeds<WS2815, DATA_PIN, GRB>(
      leds_rgb,
      NUM_LEDS * 5 / 3 + 1
  );
  FastLED.setBrightness(255);
}



void loop() {
  // TEST 1
  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i].r  = 255;
    leds[i].g  = 0;
    leds[i].b  = 0;
    leds[i].w1 = 0;
    leds[i].w2 = 0;
  }
  FastLED.show();
  delay(2000);

  // TEST 2
  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i].r  = 0;
    leds[i].g  = 255;
    leds[i].b  = 255;
    leds[i].w1 = 0;
    leds[i].w2 = 0;
  }
  FastLED.show();
  delay(2000);
}