// ── NodeMCU ESP8266 v3 — Dual LED Blink ──────────────────────────────────────
// Blinks the onboard LED (D4 / GPIO2, active-LOW) and an external LED on D5.
// Shows both pin-label and GPIO-number styles — either works.
// ─────────────────────────────────────────────────────────────────────────────

// Using D-label macros (defined by esp8266 board package)
#define ONBOARD_LED  D4    // GPIO 2 — active LOW
#define EXT_LED      D5    // GPIO 14 — active HIGH

void setup() {
  Serial.begin(115200);
  delay(100);  // Let serial settle

  pinMode(ONBOARD_LED, OUTPUT);
  pinMode(EXT_LED, OUTPUT);

  // Start with both off
  digitalWrite(ONBOARD_LED, HIGH);  // HIGH = off for active-LOW LED
  digitalWrite(EXT_LED, LOW);

  Serial.println("
────────────────────────────────");
  Serial.println("NodeMCU ESP8266 — Dual LED Blink");
  Serial.printf("CPU: %d MHz  |  Free heap: %d B
",
                ESP.getCpuFreqMHz(), ESP.getFreeHeap());
  Serial.println("───────────────────────────────
");
}

void loop() {
  // Phase A: onboard LED on, external off
  digitalWrite(ONBOARD_LED, LOW);   // LOW = ON (active-LOW)
  digitalWrite(EXT_LED,     LOW);   // off
  Serial.println("Onboard ON / External OFF");
  delay(500);

  // Phase B: onboard off, external on
  digitalWrite(ONBOARD_LED, HIGH);  // HIGH = OFF
  digitalWrite(EXT_LED,     HIGH);  // HIGH = ON
  Serial.println("Onboard OFF / External ON");
  delay(500);

  // Phase C: both on briefly
  digitalWrite(ONBOARD_LED, LOW);
  digitalWrite(EXT_LED,     HIGH);
  Serial.println("Both ON");
  delay(200);

  // Reset
  digitalWrite(ONBOARD_LED, HIGH);
  digitalWrite(EXT_LED,     LOW);
  delay(300);
}