Patent ID: 7234071

Claim:
An on-chip real time clock module for use on a digital processing integrated circuit, the on-chip real time clock module comprises: a plurality of persistent registers operable to periodically store operational parameters and timing parameters of the digital processing integrated circuit, wherein the plurality of persistent registers are powered by a battery and receive a timing signal from a crystal oscillator; a clock domain crossing module operably coupled to the plurality of persistent registers, wherein the clock crossing domain module synchronizes a crystal oscillator clock domain produced by the crystal oscillator and a system clock domain produced by a system clock circuit of the digital processing integrated circuit; an input buffer operably coupled to receive operational parameters and timing parameters from the digital processing integrated circuit in accordance with the system clock domain and to provide the operational parameters and timing parameters to one of the plurality of persistent registers in accordance with the crystal oscillator clock domain; and an output buffer operably coupled to retrieve operational parameters and timing parameters from the plurality of persistent registers in accordance with the crystal clock domain and to provide the retrieved operational parameters and timing parameters to the digital processing integrated circuit in accordance with the system clock domain.