A nonvolatile memory includes a memory cell array including a plurality of memory cells, a pad configured to be connected to a data input/output line, and an input/output circuit configured to receive data to be programmed in the memory cell array and to transmit data read from the memory cell array. The nonvolatile memory further includes a switch configured to couple and decouple the pad and the input/output circuit responsive to a switch control signal and a control circuit configured to generate the switch control signal responsive to a chip enable signal. Data storage devices and methods using such nonvolatile memories are also described.