Watchdog Timer (WDT) Tips and Tricks
  • A test you can do to observe the time that the Watchdog Timer (WDT) is running is to toggle an IO pin and/or an LED around the CLRWDT function. If there is no LED connected, this test can be observed on an oscilloscope.
  • It is good practice to clear the WDT only once during the length of your program. This is because you need to clear the WDT before the timer times out and resets the program. Having multiple CLRWDT instructions makes it difficult to keep track of when the timer will time out.
  • Using the timer interrupt to clear WDT is not recommended because the WDT is an emergency feature to reset the system on an "un-escapable loop" where an interrupt can still happen within the loop. If you clear the WDT in the timer interrupt, it will be cleared as part of the interrupt and the program will return to the loop and stay stuck in the loop as before.
© 2024 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.