Patent ID: 8245068

Claim:
A device having a power supply monitoring capabilities, the device comprises: a power supply unit; at least one real time clock generator counter adapted to receive a supply voltage from the power supply unit; a fixed value storage circuit that is un-accessible to software executed by a processor, wherein the fixed value storage circuit stores a fixed value, wherein the fixed value includes multiple bits; a volatile storage unit, being accessible to the processor, wherein the volatile storage unit is adapted to: receive the fixed value during an initialization state of the device; store the fixed value as a value at the volatile storage unit in response to receiving the fixed value; and writing a first value as the value at the volatile storage unit in response to the volatile storage unit being reset, wherein the first value is different than a reset value of the volatile storage unit; wherein the volatile storage unit is designed such that there is a low probability that the first value equals the fixed value; and a comparator adapted to provide a tamper indication if the fixed value stored at the fixed value storage circuit differs from the value stored at the volatile storage unit.