Patent ID: 6253319
Filing Date: 2001-06-26
Classification: G06F

Abstract:
A multifunction circuit that comprises:a power switch having a first terminal and a second terminal, wherein the power switch is a momentary switch that is normally open;a first resistor coupled between a positive power source terminal and the first terminal of the power switch;an RC circuit coupled between the second terminal of the power switch and a ground voltage, wherein the RC circuit has a time constant of less than 500 ms;a first sub-circuit coupled to the second terminal of the power switch, coupled to a positive battery terminal, and configured to generate a signal to invalidate contents of a nonvolatile configuration memory in response to closure of the power switch, wherein said first sub-circuit includes:a first gate coupled between the positive battery terminal and a power supply node for the nonvolatile configuration memory;an invalidation signal node coupled to a first gate, wherein the first gate becomes an open circuit when the invalidation signal is asserted, and wherein the first gate conducts when the invalidation signal is de-asserted;a second gate coupled between the invalidation signal node and the second terminal of the power switch, wherein the second gate is also coupled to the positive power source terminal and configured to become an open circuit when the positive power source terminal is high, and configured to conduct when the positive power source terminal is low.