Watchdog circuit for use with processor circuit has self monitoring function - using dynamic feedback of output to timer monostables to indicate circuit failure condition

摘要

The watchdog circuit for a processor has the address bus coupled to a register (1) having the output coupled to a mixer (2) with a shift register (3). The register output provides input to one port of an exclusive -OR (4) generating the circuit output (A) and also providing inputs to a pair of monostables (6, 7) coupled via a trigger (5) to the shift-register. The dynamic coupling of the output of the watchdog circuit back to the timer function monostables (6, 7) ensures that a failure in the circuit is immediately signalled. USE/ADVANTAGE - Provides indication of watchdog circuit failure.