External Watchdog Timer

The watchdog timer is monitors an I/O line from the
mC system. This line must be toggled once every interval time to
verify correct software execution. Failure to toggle the line indicates
that the mC system is not correctly executing its program
and may be tied up in an endless loop. If this happens, a reset
pulse is generated to initialize the processor.

ADM8690–ADM8695
The ADM8690–ADM8695 family of supervisory circuits offers
complete single chip solutions for power supply monitoring and
battery control functions in microprocessor systems. These
functions include mP reset, backup battery switchover, watchdog
timer, CMOS RAM write protection and power failure warning.
The complete family provides a variety of configurations to satisfy
most microprocessor system requirements.