Memory device using extra read and write commands

1. A memory device, comprising:

one or more multi-channel memories; and

an interface unit suitable for interfacing with the multi-channel memories, the interface unit comprising:

a first data interface suitable for transferring data for a first channel of the multi-channel memories;

a second data interface suitable for transferring data for a second channel of the multi-channel memories; and

an extra data interface suitable for additionally transferring data for a selected one of the first channel and the second channel.

2. The memory device of claim 1 , wherein:

when an extra read command for the first channel is applied, data read from the first channel of the multi-channel memories is output through both of the first data interface and the extra data interface, and

when an extra read command for the second channel is applied, data read from the second channel of the multi-channel memories is output through both of the second data interface and the extra data interface.

3. The memory device of claim 2 , wherein:

when the extra read command for the first channel is applied, the data output through the first data interface and the data output through the extra data interface are different, and

when the extra read command for the second channel is applied, the data output through the second data interface and the data output through the extra data interface are different.

4. The memory device of claim 1 , wherein:

when an extra write command for the first channel is applied, data inputted through both of the first data interface and the extra data interface is written in the first channel of the multi-channel memories, and

when an extra write command for the second channel is applied, data inputted through both of the second data interface and the extra data interface is written in the second channel of the multi-channel memories.

5. The memory device of claim 4 , wherein:

when the extra write command for the first channel is applied, the data inputted through the first data interface and the data inputted through the extra data interface are different, and

when the extra write command for the second channel is applied, the data inputted through the second data interface and the data inputted through the extra data interface are different.

6. The memory device of claim 1 , wherein the interface unit further comprises:

a first command interface suitable for receiving a command for the first channel;

a second command interface suitable for receiving a command for the second channel;

a first address interface suitable for receiving an address for the first channel; and

a second address interface suitable for receiving an address for the second channel.

7. The memory device of claim 1 , wherein the multi-channel memories are stacked over the interface unit.

8. A memory device, comprising:

one or more multi-channel memories; and

an interface unit suitable for interfacing with the multi-channel memories, the interface unit comprising:

a first data interface; and

a second data interface,

wherein only the first data interface outputs data read from a first channel of the multi-channel memories when a read command for the first channel is applied,

only the second data interface outputs data read from a second channel of the multi-channel memories when a read command for the second channel is applied,

both of the first data interface and the second data interface output data read from the first channel when an extra read command for the first channel is applied, and

both of the first data interface and the second data interface output data read from the second channel when an extra read command for the second channel is applied.

9. The memory device of claim 8 , wherein:

when a write command for the first channel is applied, data inputted through only the first data interface is written in the first channel,

when a write command for the second channel is applied, data inputted through only the second data interface is written in the second channel,

when an extra write command for the first channel is applied, data inputted through both of the first data interface and the second data interface is written in the first channel, and

when an extra write command for the second channel is applied, data inputted through both of the first data interface and the second data interface is written in the second channel.

10. The memory device of claim 8 , wherein:

when the extra read command for the first channel is applied, the data output through the first data interface and the data output through the second data interface are different, and

when the extra read command for the second channel is applied, the data output through the first data interface and the data output through the second data interface are different.

11. The memory device of claim 9 , wherein:

when the extra write command for the first channel is applied, the data inputted through the first data interface and the data inputted through the second data interface are different, and

when the extra write command for the second channel is applied, the data inputted through the first data interface and the data inputted through the second data interface are different.

12. The memory device of claim 8 , wherein the interface unit further comprises:

a first command interface suitable for receiving a command for the first channel;

a second command interface suitable for receiving a command for the second channel;

a first address interface suitable for receiving an address for the first channel; and

a second address interface suitable for receiving an address for the second channel.

13. The memory device of claim 8 , wherein the multi-channel memories are stacked over the interface unit.