Patent ID: 6996732

Claim:
In a microcomputer system wherein a watchdog circuit will generate a microcomputer reset signal after the elapse of a predetermined time interval with no signal state change at the input of the watchdog circuit, but wherein the system is required to shut down or sleep for extended periods of time as for energy conservation until a wake-up signal is asserted to restart the microcomputer, a method of modified watchdog circuit operation, that comprises, generating an independent substantially rectangular-wave signal of period less than said predetermined time interval; applying the rectangular-wave signal to the watchdog circuit, including during the microcomputer sleep period, to inhibit its generation of a microcomputer reset signal; and, upon the assertion of a wake-up signal, terminating the application of the rectangular-wave signal to the watchdog circuit until the normally operating microcomputer causes the wake-up signal to be de-asserted, thereby reapplying the rectangular-wave signal to the watchdog circuit.