On-chip realtime clock module has input buffer receiving operational and timing parameters and output buffer retrieving the parameters

Abstract

A real time clock module maintains operating and timing parameters in 'non-volatile' or persistent memory when an integrated circuit is powered down. The real time clock module provides is divided into an analog and a digital domain. The analog domain contains a number of persistent registers to store operational parameters and timing parameters. These persistent registers are powered by a battery and receive a timing clock signal from a crystal oscillator. A clock domain-crossing module operably couples to the persistent registers and allows the analog domain and the digital domain to be synchronized. An input buffer receives the operational and timing parameters for the persistent registers from the digital domain and an output buffer allows the digital domain to retrieve the operational parameters and timing parameters from the persistent registers according to the clock crossing domain module.