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.
Overview
Syllabus
Welcome Back!
Reasons for MCUs hanging
JLCPCB PCBs $2 - How to generate files for PCB assembly
End of JCLPCB walk through
Circuit diagram from the article
Whiteboard: 555 Timer
Whiteboard end
Measuring capacitor charge
Oscilloscope trace of trigger
EasyEDA modified circuit layout
Where to buy the components
Combined shipping costs from Banggood
Engineer's Mini Notebook: 555 Timer IC Circuits Forrest M III Mimms
PCB Layout example
Holiday Destination Calculator
Taught by
Ralph S Bacon
