This is the documentation for the latest development branch of MicroPython and may refer to features that are not available in released versions.

If you are looking for the documentation for a specific release, use the drop-down menu on the left and select the desired version.

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.

Example usage:

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

Availability: ESP32, ESP8266, MIMXRT, RP2, SAMD, STM32, Zephyr

Constructors

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

Create a WDT object and start it. The timeout must be given in milliseconds. Once it is running the timeout cannot be changed and the WDT cannot be stopped either.

Notes:

• On the esp8266 port a timeout cannot be specified, it is determined by the underlying system.

• On rp2040 devices the maximum timeout is 8388 ms.

• On the stm32 port the default id=0 is the IWDG, which can also be specified by an id of "IWDG". Use an id of "WWDG" to access the WWDG peripheral. For dual-core STM32H7 MCUs there are also "IWDG2" and "WWDG2". The WWDG has a very limited maximum timeout across all MCUs, of around 100ms (but it depends heavily on the APB clock).

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.