Patent ID: 7581070

Claim:
A multi-chip package device, comprising: first and second memory chips configured to share addresses and control signals, wherein each of the first and second memory chips comprises: main memory for storing data, buffer memory for temporarily storing data written to and read from the main memory, an option terminal for receiving an option voltage, an access signal generation block for generating a main access signal driving access to the main memory and a buffer access signal driving access to the buffer memory in response to the addresses and the control signals, the main access signal and the buffer access signal having logic states that are determined according to a level of the option voltage, the buffer access signal undergoing a one-way transition in response to a boot code address when a predetermined internal address composed of remaining address bits except a most significant bit of a shared address specifies the boot code address, and a controller for performing control to select the main memory and the buffer memory in response to the main access signal and the buffer access signal; wherein the option voltages provided to the first and second memory chips have different voltage levels from each other; wherein the main memory of the first memory chip stores boot code that includes a program capable of performing an operation in conformity with a certain priority processing command; wherein the buffer memory of the first memory chip includes boot memory for temporarily storing the boot code, the boot memory being specified in response to the boot code address; wherein the main memory of the second memory chip does not store any boot code; wherein the buffer memory of the second memory chip does not include any boot memory; and wherein the one-way transition of the buffer access signal of the first memory chip is a transition to an activation level, and the one-way transition of the buffer access signal of the second memory chip is a transition to an inactivation level.