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Watchdog Timer | NexaLearn IoT Lab | NexaLearn

Industrial Systems (IIoT)20 دقيقة

Watchdog Timer

How to rescue the robot if the code completely freezes — without human intervention.

Lesson Content

Suppose the robot is operating in a remote location or factory, and a programming fault causes it to freeze in an infinite loop. Who will restart it? The Watchdog is a hard countdown timer inside the processor — your program must continuously reset it. If your program freezes, the timer expires and the Watchdog forces a Hardware Reset to immediately revive the system.

Components Needed

Arduino Uno أو ESP32

Code Example

#include <avr/wdt.h>
void setup() {
  Serial.begin(9600);
  wdt_enable(WDTO_2S); // عداد لثانيتين
}
void loop() {
  wdt_reset(); // يجب تصفير العداد قبل مرور ثانيتين
  // إذا وضعنا هنا delay(3000) سيعيد الأردوينو التشغيل فوراً
}

Common Mistakes

Enabling the Watchdog with a very short period and using a long delay() in setup() — the Arduino will get stuck in an infinite reboot loop the moment it's programmed.

Next Lesson

Advanced Stepper Control (A4988)