class WDT – watchdog timer

The WDT is used to restart the system when the application crashes and ends up into a non recoverable state. Once started it cannot be stopped or reconfigured in any way. After enabling, the application must “feed” the watchdog periodically to prevent it from expiring and resetting the system.

Note that on the RI5, the WDT will continue running after a program ends, and it will still reset the system if it expires during another program or in the menu system. A hard reset will get rid of it though.

Example usage:

from machine import WDT
wdt = WDT(timeout=2000)  # enable it with a timeout of 2s
wdt.feed()

Constructors

class machine.WDT(id=0, timeout=5000)

Create a WDT object and start it. The timeout must be given in seconds and the minimum value that is accepted is 1 second. Once it is running the timeout cannot be changed and the WDT cannot be stopped either.

Methods

wdt.feed()

Feed the WDT to prevent it from resetting the system. The application should place this call in a sensible place ensuring that the WDT is only fed after verifying that everything is functioning correctly.

On the RI5, note that if you’ve used a particular WDT before ever, feeding it starts it running, even if it wasn’t running after a reset! The system seems to remember that a WDT has been used even after a full power off, although it may reset to the default timeout.