ESP32 GPIO Interrupt Not Firing

In this tutorial, you'll learn about ESP32 GPIO Interrupt Not Firing. We cover key concepts, practical examples, and best practices.

The Problem

ESP32 GPIO interrupt attached to a pin does not trigger the ISR function.

Quick Fix

Wrong

attachInterrupt(4, myISR, RISING);  // ISR does nothing

No interrupt fires even when pin 4 sees rising edges.

Right

volatile bool triggered = false;
void IRAM_ATTR myISR() {
  triggered = true;
}
pinMode(4, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(4), myISR, FALLING);
void loop() {
  if (triggered) {
    triggered = false;
    Serial.println("Interrupt fired");
  }
}

Interrupt fired
(Triggered on every falling edge at GPIO 4)

Prevention

Declare ISR as IRAM_ATTR to place in IRAM. Use digitalPinToInterrupt() to get the correct interrupt number. Keep ISR short and set a volatile flag. Use FALLING/RISING/CHANGE for edge detection. Avoid Serial.print() inside ISR.

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

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