Watchdog Timer

What is a Watchdog Timer and How Does It Work? In an ideal world, software runs flawlessly, and computer hardware never glitches. In reality, embedded systems encounter unexpected conditions: a code bug triggers an infinite loop, a voltage spike corrupts memory, or a cosmic ray flips a critical bit. When a system hangs in a remote or safety-critical environment—like a Mars rover, an automotive control unit, or an industrial pacemaker—a human cannot simply press a manual reset button.

This is where a Watchdog Timer (WDT) comes in. Acting as an electronic bodyguard, a watchdog timer is a specialized hardware or software countdown mechanism designed to automatically detect system failures and reboot an unresponsive processor back into a safe operating state. How a Watchdog Timer Works

At its core, a watchdog timer functions like a dead man’s switch. It relies on a simple premise: “Prove to me that you are functioning normally, or I will reboot the system.”