US Patent 7213121 Memory device having asynchronous/synchronous operating modes

An integrated circuit memory device comprises a memory array to store data, a circuit to output the data at a pin, and a register to store a value that indicates a mode of operation of the integrated circuit memory device. The mode of operation is selected from at least one of a synchronous mode of operation and an asynchronous mode of operation. During the synchronous mode of operation, the circuit outputs the data in response to a transition of an external clock signal. During the asynchronous mode of operation, the circuit outputs the data after a period of time from when a transition of an external control signal is detected.