Patent ID: 6178523
Filing Date: 2001-01-23
Classification: G06F

Abstract:
A battery-operable portable electronic device adapted to receive a removable main power source, comprising: electronic circuits, an auxiliary power source, and coupling and detection means for electrically coupling the main or the auxiliary power source to at least a part of the electronic circuits, and for detecting a power failure in said main power source, the coupling and detection means being configured for generating an electrical disconnect main power source interrupt signal upon electrical disconnection of the main power source from the coupling and detection means, the electronic circuits comprising:a processing unit including memory means for storing an operational program for operating the portable device, a set of operational registers, and a stack, the processing unit being adapted to respond to at least one external interrupt signal,wherein the processing unit is configured for responding to the electrical disconnect main power source interrupt signal by pushing at least a subset of the set of operational registers on the stack so as to save an exact operational point of a currently executed program function of the operational program in the portable device, by pushing a main power source check routine on the stack, and by executing the main power source check routine on the stack, the main power source check routine restoring the at least saved subset of the set of operational registers, and causing the processing unit to return to the saved exact operational point of the currently executed program function, upon determining whether the main power source is electrically reconnected.