Communication with HW Watchdog

Raspberry Pi offers hardware-based Watchdog functionality.

The watchdog is triggered when writing a first time to the /dev/watchdog. When the watchdog does not receive a heartbeat signal from the control application for 15 seconds, the watchdog will trigger a reboot of the system. When writing the character "V" to the watchdog file, the watchdog is deactivated.

The control application allows the configuration of:

• activation of watchdog
• watchdog file name
• heartbeat string to be sent to device
• duration between heartbeat signals in milliseconds
• deactivation string to be sent to device (needs to be "V")

For testing purposes, one can stop the control application from sending a heartbeat signal to the watchdog, inducing a reset of the system: aquarium_client watchdog stop .