Patent ID: 7962773

Claim:
A microcontroller unit (MCU) with a stand-alone Real Time Clock (RTC), comprising: a processing circuit for receiving digital information and processing said received digital information and having a clock input for receiving a clock signal; a primary clock circuit for providing the clock signal to the clock input of said processing circuit; a power control circuit for controlling the power to said processing circuit and said primary clock circuit to control the operation thereof to operate in at least a full power mode drawing a full power level from a supply voltage input and a reduced power mode drawing less than the full power level from said supply voltage input; and a stand-alone RTC circuit, said stand-alone RTC circuit including: an RTC clock circuit operating independent of said primary clock circuit with an independent RTC clock time base, a timer operating on said RTC time base to increment a stored time value, circuitry for controlling said power control circuit to remove at least one of said processing circuit or said primary clock circuit from the reduced power mode, and power management circuitry for managing the power to said stand-alone RTC circuit, such that said RTC clock circuit, said timer, and said I/O device operate regardless of the power mode of operation of said processing circuit and said primary clock circuit.