Memory system and data channel initialization method thereof

The pins without an increase of the semiconductor memory device and the memory to initiate a data channel at a high speed without a circuit for performing initialization function system and a data channel initialization method thereof are disclosed. Said memory system, comprising: a plurality of semiconductor memory devices have a data channel and a command / address channel connected between a control memory module, the semiconductor memory device which is mounted a memory controller, and the memory controller and the semiconductor memory device, and write latency of the read latency of the semiconductor memory device and the semiconductor memory device are characterized in that the control by the memory controller. The semiconductor memory devices each having a predetermined output delay time depending on the read latency and outputs data. The semiconductor memory devices each with a predetermined delay time according to the input write latency input data.