Patent ID: 8010818

Claim:
A method for saving power in a device coupled to a bus, the method comprising: placing the device to operate in a power saving mode by powering off a selective portion of the device; determining whether data communication over the bus is addressed to the device; triggering the selective portion to transition to a power on state in response to determining that the data communication is addressed to the device; storing the data communication in shadow registers; and transferring the data communication stored in the shadow registers to a register map, the transferring being controlled by the selective portion operating in the power on state, and the transferring includes the substeps of: receiving a first pulse of an oscillator included in the selective portion of the device; storing the data communication in the register map responsive to the first pulse, the data communication including a data portion and a data address portion, the data portion being stored at a valid address location in the register map pointed to by the data address portion stored in the shadow registers; comparing the data address portion and a maximum address plus 1; generating a clear pulse signal is response to the address portion being less than the maximum address plus 1; and resetting the shadow registers with the clear pulse signal.