Nonvolatile memory device, storage device including nonvolatile memory devices, and method of training data input and output lines between controller and nonvolatile memory devices

A storage device comprising:

• a plurality of nonvolatile memory devices;
• and
• a controller connected to the plurality of nonvolatile memory devices through data lines,
• wherein:
• the controller is configured to store first offset information by performing a first training operation on a first nonvolatile memory device from among the plurality of nonvolatile memory devices,
• the controller is further configured to, based on the first offset information, perform a second training operation on a second nonvolatile memory device from among the plurality of nonvolatile memory devices,
• during the first training operation, the controller is configured to output read enable signal to the first nonvolatile memory device through a signal line,
• during the first training operation, the first nonvolatile memory device is configured to output data strobe signal to the controller through a data strobe signal line,
• during the first training operation, the first nonvolatile memory device is configured to output first data bits to the controller through the data lines in synchronization with the data strobe signal, and
• the read enable signal toggles with a certain period during a first time interval and stop toggling with the certain period during a second time interval.