Ard Serial Event

In this tutorial, you'll learn about Arduino serialEvent Never Fires. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

The Problem

The serialEvent() function is never called even when data arrives on serial.

Quick Fix

Wrong

void serialEvent() {
  // This never runs!
  String msg = Serial.readString();
}

serialEvent() is never triggered.

Right

void setup() {
  Serial.begin(9600);
}

void loop() {
  if (Serial.available()) {
    String msg = Serial.readStringUntil('\n");
    Serial.print("Echo: ');
    Serial.println(msg);
  }
  // Other loop tasks
}

Echo: test  (immediately when data arrives).

Prevention

serialEvent() is a legacy Arduino function that only works with the standard Arduino framework on some boards. It is called between loop() iterations. On ESP32, STM32, and other platforms, it is not supported. Use Serial.available() in loop() instead.

DodaTech engineers apply these same patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro for production IoT reliability.

FAQ