Semiconductor memory device and memory system

1. A memory system comprising:

a semiconductor memory device including a plurality of memory cells, and first, second, and third caches for storing data before the data are written into the memory cells; and

a memory controller configured to issue commands to the semiconductor memory device, the commands including a first command issued with first write data to store the first write data in the first cache, a second command issued with second write data to store the second write data in the first cache and then transfer the second write data in the first cache to one of the second and third caches, and a third command to transfer data between the second and third caches.

2. The memory system according to claim 1 , wherein the semiconductor memory device, in response to the first command issued with the first write data, stores the first write data in the first cache.

3. The memory system according to claim 2 , wherein the semiconductor memory device, in response to the second command issued with the second write data, stores the second write data in the first cache and then transfers the second write data in the first cache to one of the second and third caches.

4. The memory system according to claim 3 , wherein a time period for executing the first command in the semiconductor memory device is less than a time period for executing the second command in the semiconductor memory device.

5. The memory system according to claim 1 , wherein the memory controller issues the first command with first address data, the first address data indicating one of the second and third caches as a destination of the first write data, and issues the second command with second address data, the second address data indicating one of the second and third caches as a destination of the second write data.

6. The memory system according to claim 5 , wherein the semiconductor memory device, in response to the first and second commands, stores the corresponding first or second write data in the first cache and sets a logic state of a control signal to a first state if the destination of the corresponding first or second write data is the second cache and to a second state if the destination of the corresponding first or second write data is the third cache.

7. The memory system according to claim 6 , wherein the semiconductor memory device, in response to the second command, further transfers the second write data in the first cache to the destination.

8. The memory system according to claim 1 , wherein the commands include a fourth command issued with fourth write data to store the fourth write data in the first cache, perform a logic operation on the fourth write data and data stored in one of the second and third caches, and store a result of the logic operation in said one of the second and third caches.

9. The memory system according to claim 1 , wherein the commands include a fourth command to transfer data stored in one of the second and third caches to the first cache and read the data transferred to the first cache.

10. A memory system comprising:

a semiconductor memory device including

a first group of memory cells and a second group of memory cells,

first, second, and third caches for storing data before the data are written into the memory cells of the first group, and

fourth, fifth, and sixth caches for storing data before the data are written into the memory cells of the second group; and

a memory controller configured to issue commands to the semiconductor memory device, the commands including a first command issued with first address data and first write data to store the first write data in the first or fourth cache in accordance with the first address data, a second command issued with second address data and second write data to store the second write data in the first or fourth cache in accordance with the second address data and then transfer the second write data in the first cache to one of the second and third caches or the second write data in the fourth cache to one of the fifth and sixth caches, and a third command to write the data stored in the second or third cache into the first group of memory cells and the data stored in the fifth or sixth cache into the second group of memory cells.

11. The memory system according to claim 10 , wherein the memory controller is configured to issue the first and second commands addressing different groups of memory cells in an interleaved manner.

12. The memory system according to claim 10 , wherein the semiconductor memory device, in response to the first command, stores the first write data in the first cache if the first address data indicates the memory cells of the first group are targeted and in the fourth cache if the first address data indicates the memory cells of the second group are targeted, and in response to the second command, stores the second write data in the first cache if the second address data indicates the memory cells of the first group are targeted and in the fourth cache if the second address data indicates the memory cells of the second group are targeted.

13. The memory system according to claim 12 , wherein the semiconductor memory device, in response to the first or second command, further sets a logic state of a first control signal if the corresponding first or second address data indicates the memory cells of the first group are targeted and a logic state of a second control signal if the corresponding first or second address data indicates the memory cells of the second group are targeted, the logic state of the first control signal indicating one of the second and third caches as a destination of the corresponding first or second write data in the first cache and the logic state of the second control signal indicating one of the fifth and sixth caches as a destination of the corresponding first or second write data in the fourth cache.

14. The memory system according to claim 13 , wherein the semiconductor memory device, in response to the second command, further transfers the second write data in the first cache to one of the second and third caches according to the logic state of the first control signal or the second write data in the fourth cache to one of the fifth and sixth caches according to the logic state of the second control signal.

15. The memory system according to claim 10 , wherein the commands include a fourth command issued with fourth address data and fourth write data to store the fourth write data in one of the first or fourth cache in accordance with the fourth address data, initialize the other one of the first or fourth cache, and then transfer the fourth write data in the first cache to one of the second and third caches or the fourth write data in the fourth cache to one of the fifth and sixth caches.

16. A semiconductor memory device, comprising:

a first group of memory cells and a second group of memory cells;

first, second, and third caches for storing data before the data are written into the memory cells of the first group;

fourth, fifth, and sixth caches for storing data before the data are written into the memory cells of the second group; and

a control unit configured to process commands received from an external unit, the commands including a first command issued with first address data and first write data to store the first write data in the first or fourth cache in accordance with the first address data, a second command issued with second address data and second write data to store the second write data in the first or fourth cache in accordance with the second address data and then transfer the second write data in the first cache to one of the second and third caches or the second write data in the fourth cache to one of the fifth and sixth caches, and a third command to write the data stored in the second or third cache into the first group of memory cells and the data stored in the fifth or sixth cache into the second group of memory cells.

17. The semiconductor memory device according to claim 16 , wherein the control unit, in response to the first command, stores the first write data in the first cache if the first address data indicates the memory cells of the first group are targeted and in the fourth cache if the first address data indicates the memory cells of the second group are targeted, and in response to the second command, stores the second write data in the first cache if the second address data indicates the memory cells of the first group are targeted and in the fourth cache if the second address data indicates the memory cells of the second group are targeted.

18. The semiconductor memory device according to claim 17 , wherein the control unit, in response to the first or second command, further sets a logic state of a first control signal if the corresponding first or second address data indicates the memory cells of the first group are targeted and a logic state of a second control signal if the corresponding first or second address data indicates the memory cells of the second group are targeted, the logic state of the first control signal indicating one of the second and third caches as a destination of the corresponding first or second write data in the first cache and the logic state of the second control signal indicating one of the fifth and sixth caches as a destination of the corresponding first or second write data in the fourth cache.

19. The semiconductor memory device according to claim 18 , wherein the control unit, in response to the second command, further transfers the second write data in the first cache to one of the second and third caches according to the logic state of the first control signal or the second write data in the fourth cache to one of the fifth and sixth caches according to the logic state of the second control signal.

20. The semiconductor memory device according to claim 16 , wherein the commands include a fourth command issued with fourth address data and fourth write data to store the write data in one of the first or fourth cache in accordance with fourth the address data, initialize the other one of the first or fourth cache, and then transfer the write data in the first cache to one of the second and third caches or the write data in the fourth cache to one of the fifth and sixth caches.