attiny-wdt¶

attiny-wdt is an OSHW + open source firmware project of turning an Attiny{4,5,9,10} microcontroller into a hardware watchdog that can be used to reset another CPU/SoC when it gets stuck.

The primary use case was to use it with Raspberry Pi devices. Those do have a built-in hardware watchdog themselves, but unfortuantelly it is not documented at the register-level and there is no option to enable it straight from the boot loader, so it is not really providing the kind of guarantees one would expect from a watchdog.

Pictures¶

The pictures below show three hand-soldered prototypes: