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.

Available on STM32 OpenMV cams (M4 / M7 / H7 / H7 Plus / Pure Thermal / N6) and the OpenMV Cam RT1062. Not exposed on the OpenMV Cam AE3 (alif port).

Example usage:

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

Constructors

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

Create a WDT object and start it. timeout is given in milliseconds. Once started the watchdog cannot be stopped; use timeout_ms() to change the window at runtime.

Methods

feed() → None

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.

timeout_ms(timeout: int) → None

Change the watchdog timeout to timeout milliseconds and reload the counter. Useful when one of several states needs a longer-than-default window before the next feed(). The new timeout takes effect immediately. STM32 only.