External Watchdog Timer - Prevent Latch-Hang Ups in a µController

Learn how to implement an external watchdog timer using the popular 555 integrated circuit to prevent microcontroller hang-ups and latch-ups. Explore the circuit diagram, whiteboard explanations of the 555 timer functionality, and oscilloscope traces of the trigger mechanism. Follow along with a modified circuit layout in EasyEDA, get component sourcing tips, and see PCB layout examples. Gain insights into microcontroller failure modes and protection strategies, with references to technical resources on latch-up prevention. This comprehensive tutorial covers both theoretical concepts and practical implementation, making it valuable for electronics enthusiasts and embedded systems developers looking to improve the reliability of their microcontroller-based projects.

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Circuit diagram from the article
Whiteboard: 555 Timer
Whiteboard end
Measuring capacitor charge
Oscilloscope trace of trigger
EasyEDA modified circuit layout
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