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US 4,788,661 AGranted
Microcomputer reset circuit
AssigneeClarion Co., Ltd.
InventorTetsuya Morita
Life of this patent
Estimating the term…
Abstract
A reset circuit controlled by a comparator circuit detecting the voltage of the power supply and incorporating a circuit which outputs reset pulses with a constant period and inhibits output of the reset pulses when it receives a reset inhibition pulse from a microcomputer.
Claims4
A reset circuit for resetting the operation of a microcomputer operating according to a program stored therein comprising:
- a reset pulse generator for outputting reset pulses to said microcomputer;
- and
- a timer for establishing a first time interval when said reset pulse is to be produced and acting on said reset pulse generator to produce said reset pulse at the end of said first time interval, said microcomputer including program-controlled means for periodically providing a reset inhibiting pulse within a second time interval shorter than said first time interval in normal execution of said program and outputting said reset inhibiting pulse to said timer to reset the operation thereof so that failure of said microcomputer to output a reset inhibiting pulse within said first time interval resets said microcomputer.
Dependencies are inferred from the claim text.