Memory device with pipelined access

1. A memory device comprising:

a memory cell capable of holding data;

an ECC circuit capable of generating a correction code and detecting an error based on the correction code; and

at least two address buffers,

wherein the memory cell is accessed by a pipeline operation, and the pipeline operation includes at least four pipeline stages including

a read cycle reading data from the memory cell,

an ECC cycle executing generation of the correction code or error detection for the memory cell in the ECC circuit,

a wait cycle during which processing for data related to the memory cell is not executed and

a write cycle writing data into the memory cell, and

wherein the address buffers include

a write address buffer capable of holding an address of the memory cell received from an outside during an operation of writing data, and

a read address buffer capable of holding an address of the memory cell received from an outside during an operation of reading data.

2. The memory device according to claim 1 , further comprising:

a write data buffer capable of holding write data into the memory cell;

a read data buffer capable of holding read data from the memory cell;

a first signal path capable of transferring data from the read data buffer to the write data buffer; and

a second signal path capable of transferring data from the write data buffer to the read data buffer.

3. A memory device comprising:

a memory cell capable of holding data; and

an ECC circuit capable of generating a correction code and detecting an error based on the correction code,

wherein the memory cell is accessed by a pipeline operation, and the pipeline operation includes at least four pipeline stages including

a read cycle reading data from the memory cell,

an ECC cycle executing generation of the correction code or error detection for the memory cell in the ECC circuit,

a wait cycle during which processing for data related to the memory cell is not executed and

a write cycle writing data into the memory cell,

the pipeline operation during an operation of reading data from the memory cell is executed in order of the read cycle, the ECC cycle, the wait cycle, and the write cycle, and

the pipeline operation during an operation of writing data into the memory cell is executed in order of the read cycle, the wait cycle, the ECC cycle, and the write cycle.

4. The memory device according to claim 3 , further comprising:

a sense amplifier that senses read data from the memory cell; and

a write driver that writes data to the memory cell,

wherein the sense amplifier operates in the read cycle in the at least four pipeline stages, and then the write driver operates in the write cycle in the at least four pipeline stages.

5. The memory device according to claim 1 ,

wherein the memory device is one of a magnetoresistive random access memory (MRAM), a resistive random access memory (ReRAM), and a phase change memory (PCM).

6. A memory device comprising:

a memory cell capable of holding data; and

an ECC circuit capable of generating a correction code and detecting an error based on the correction code,

wherein the memory cell is accessed by a pipeline operation, and the pipeline operation includes at least four pipeline stages including

a read cycle reading data from the memory cell,

an ECC cycle executing generation of the correction code or error detection for the memory cell in the ECC circuit,

a wait cycle during which processing of data related to the memory cell is not executed and

a write cycle writing data into the memory cell,

wherein, during an operation of writing data into the memory cell, read data read from the memory cell in the read cycle is compared with write data received from an outside, and

as a result of the comparison, when the read data is different from the write data, the write data is written into the memory cell.

7. The memory device according to claim 6 , further comprising:

at least two or more address buffers,

wherein the address buffers include

a write address buffer capable of holding an address of the memory cell received from an outside during an operation of writing data, and

a read address buffer capable of holding an address of the memory cell received from an outside during an operation of reading data.

8. The memory device according to claim 7 , further comprising:

a write data buffer capable of holding write data into the memory cell;

a read data buffer capable of holding read data from the memory cell;

a first signal path capable of transferring data from the read data buffer to the write data buffer; and

a second signal path capable of transferring data from the write data buffer to the read data buffer.

9. The memory device according to claim 6 ,

wherein the pipeline operation during an operation of reading data from the memory cell is executed in order of the read cycle, the ECC cycle, the wait cycle, and the write cycle, and

the pipeline operation during an operation of writing data into the memory cell is executed in order of the read cycle, the wait cycle, the ECC cycle, and the write cycle.

10. The memory device according to claim 9 , further comprising:

a sense amplifier that senses read data from the memory cell; and

a write driver that writes data to the memory cell,

wherein the sense amplifier operates in the read cycle in the at least four pipeline stages, and then the write driver operates in the write cycle in the at least four pipeline stages.

11. The memory device according to claim 6 ,

wherein the memory device is one of a magnetoresistive random access memory (MRAM), a resistive random access memory (ReRAM), and a phase change memory (PCM).

12. A memory device comprising:

a memory cell capable of holding data; and

an ECC circuit capable of generating a correction code and detecting an error based on the correction code,

wherein the memory cell is accessed by a pipeline operation, and the pipeline operation includes at least four pipeline stages including

a read cycle reading data from the memory cell,

an ECC cycle executing generation of the correction code or error detection for the memory cell in the ECC circuit,

a wait cycle during which processing for data related to the memory cell is not executed and

a write cycle writing data into the memory cell, and

the number of pipeline stages in the pipeline operation is different between a data write operation and a data read operation into and from the memory cell.

13. The memory device according to claim 12 , further comprising:

at least two or more address buffers,

wherein the address buffers include

a write address buffer capable of holding an address of the memory cell received from an outside during an operation of writing data, and

a read address buffer capable of holding an address of the memory cell received from an outside during an operation of reading data.

14. The memory device according to claim 13 , further comprising:

a write data buffer capable of holding write data into the memory cell;

a read data buffer capable of holding read data from the memory cell;

a first signal path capable of transferring data from the read data buffer to the write data buffer; and

a second signal path capable of transferring data from the write data buffer to the read data buffer.

15. The memory device according to claim 12 ,

wherein the pipeline operation during an operation of reading data from the memory cell includes at least four pipeline stages that are executed in order of the read cycle, the ECC cycle, the wait cycle, and the write cycle,

the pipeline operation during an operation of writing data into the memory cell includes at least six pipeline stages that are executed in order of the read cycle, the wait cycle, the ECC cycle, the write cycle, a verify read cycle, and a write repair cycle,

in the verify read cycle, data written in the memory cell in the write cycle is read and verified, and

in the write repair cycle, data based on a verification result in the verify read cycle is written into the memory cell.

16. The memory device according to claim 15 , further comprising:

a sense amplifier that senses read data from the memory cell; and

a write driver that writes data to the memory cell,

wherein the sense amplifier operates in the read cycle in the at least four pipeline stages, and then the write driver operates in the write cycle in the at least four pipeline stages.

17. The memory device according to claim 12 ,

wherein the memory device is one of a magnetoresistive random access memory (MRAM), a resistive random access memory (ReRAM), and a phase change memory (PCM).

18. The memory device according to claim 3 ,

wherein, when consecutively receiving a write instruction to write data into the memory cell and a read instruction to read data from the memory cell,

the memory device outputs first data including write data received with the write instruction to an outside as read data corresponding to the read instruction.

19. The memory device according to claim 18 , further comprising:

a write data buffer capable of holding write data into the memory cell;

a read data buffer capable of holding read data from the memory cell;

a first signal path capable of transferring data from the read data buffer to the write data buffer; and

a second signal path capable of transferring data from the write data buffer to the read data buffer,

wherein, when consecutively receiving the write instruction to write data into the memory cell and the read instruction to read data from the memory cell, the memory device

causes the first data including write data received with the write instruction to be held in the write data buffer,

causes second data read from the memory cell in the read cycle corresponding to the read instruction to be held in the read data buffer,

transfers the first data to the read data buffer via the second signal path, and

transfers the second data to the write data buffer via the first signal path.

20. The memory device according to claim 3 ,

wherein the memory device is one of a magnetoresistive random access memory (MRAM), a resistive random access memory (ReRAM), and a phase change memory (PCM).