Storage device and data training method thereof

A storage device comprising:

• a first chip;
• and
• a second chip configured to exchange data with the first chip,
• wherein the first chip is configured to transmit a data strobe signal and a plurality of data signals to the second chip such that different delay times are applied to each of the plurality of data signals, and
• the second chip is configured to, during data training, sample the plurality of data signals using the data strobe signal received from the first chip,
• the data training including a coarse mode and a fine mode,
• the second chip is configured to generate a coarse initial code based on a sampling result in the coarse mode,
• the first chip is configured to determine a coarse data strobe signal (DQS) delay time based on the coarse initial code and to apply the coarse DQS delay time to the data strobe signal in the fine mode, and
• the first chip is configured to additionally apply the coarse DQS delay time to the plurality of data signals in the fine mode.