Atom-Lite/Atom-Matrix RGB LED

#include <M5Unified.h>
#include <Adafruit_NeoPixel.h>

#define LED_PIN 27
#define NUM_LEDS 25

Adafruit_NeoPixel strip(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
    M5.begin();
    Serial.begin(115200);
    Serial.printf("RGB LED Test\n");
    strip.begin();
}

void loop() {
    // Red
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(255, 0, 0)); }
    strip.show();
    delay(500);

    // Green
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(0, 255, 0)); }
    strip.show();
    delay(500);

    // Blue
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(0, 0, 255)); }
    strip.show();
    delay(500);

    // Yellow
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(255, 255, 0)); }
    strip.show();
    delay(500);

    // Magenta
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(255, 0, 255)); }
    strip.show();
    delay(500);

    // Cyan
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(0, 255, 255)); }
    strip.show();
    delay(500);

    // White (all on)
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(255, 255, 255)); }
    strip.show();
    delay(500);

    // Black (all off)
    for (char i = 0; i <= NUM_LEDS; i++) { strip.setPixelColor(i, strip.Color(0, 0, 0)); }
    strip.show();
    delay(500);
}