This project implements a long-duration digital watchdog timer that is controllable over I2C. It runs on the inexpensive ATTINY412.  This can be added to a PCB to provide flexible watchdog functionality for an embedded system.  Current pricing is about $0.50 in single unit quantities.

The project includes both embedded code for the ATTINY and a Linux host driver that presents a standard /dev/watchdog interface.

Features include:

• Programmable timeout period up to 64 seconds (+/- 10%)

• Optional ALERT signal before timeout.

• RESET and/or POWERCYCLE outputs for robust recovery.

• I2C interface.

The code is available on github.