#define TX_PIN 5  // Try GPIO5
#define RX_PIN 4  // Try GPIO4

void setup() {
    Serial.begin(115200);       // USB Serial for debugging
    Serial1.begin(9600, SERIAL_8N1, RX_PIN, TX_PIN);  // UART communication
}

void loop() {
    Serial1.println("Hello from Master!"); // Send test message
    Serial.println("Sent: Hello from Master!");

    delay(2000);
}