Memory array error correction apparatus, systems, and methods

• US 20080195894A1
• Filed: 02/12/2007
• Published: 08/14/2008
• Est. Priority Date: 02/12/2007
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Schreck, John F., Dauenbaugh, Todd A.
• Granted Patent: US 7,945,840 B2
• Time in Patent Office: Days
• US Class Current: 714/34
• CPC Class Codes: G06F 11/1056 Updating check bits on partial write, i.e. read/modify/write
• CPC Class Codes: G06F 11/106 Correcting systematically all correctable errors, i.e. scrubbing
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems

Abstract

Various embodiments include apparatus, methods, and systems that operate to extend the processes of reading, modifying, and writing data stored in or being provided to a memory array without interrupting a continual stream of data to be written into the memory array. Embodiments may include an apparatus comprising a memory array, and an error code module coupled to the memory array with a data buffer having a plurality of data burst registers operable to receive a plurality of data bursts to be written to the memory array on a corresponding plurality of consecutive clock cycles. The error code module is operable to perform a read/modify/write process on each of the plurality of data bursts within a time period no longer than a period of two consecutive cycles of the plurality of consecutive clock cycles.

Claims

1. An apparatus comprising:

a memory array; and

an error code module coupled to the memory array and including a data buffer having a plurality of data registers operable to receive a plurality of data bursts to be written to the memory array on a corresponding plurality of consecutive clock cycles, the error code module operable to perform a read/modify/write process on each of the plurality of data bursts within a time period no longer than a period of two consecutive cycles of the plurality of consecutive clock cycles.

2. The apparatus of claim 1, wherein the error code module comprises a data combiner coupled to the data buffer and operable to generate a modified data burst for each of the plurality of data bursts.

3. The apparatus of claim 2, wherein the error code module comprises a read data register coupled to the memory array and to the data combiner, the read data register operable to receive a plurality of data bits stored at an address in the memory array to which one of the plurality of data bursts is to be written, and to provide the plurality of data bits to the data combiner at about a same time the one of the plurality of data bursts is provided to the data combiner.

4. The apparatus of claim 2, comprising at least one data mask input coupled to the data combiner and operable to provide to the data combiner a data mask setting for each of the plurality of data bursts.

5. The apparatus of claim 2, comprising a modified data register coupled to the data combiner and operable to store the modified data burst.

6. The apparatus of claim 2, wherein the error code module comprises an error code computation unit coupled to the data buffer and operable to generate an error correction code for the modified data burst.

7. The apparatus of claim 6, wherein the error code module comprises an error correction code register coupled to the error code computation unit and operable to store the error correction code.

8. The apparatus of claim 7, comprising a plurality of input/output lines coupled to the error correction code register and to the memory array and operable to provide the error correction code stored at the error correction code register to the memory array.

9. The apparatus of claim 1, comprising a plurality of input/output lines coupled to the error code module and to the memory array, the error code module operable to receive a plurality of read data bits from the memory array and to write a plurality of write data bits to the memory array over the plurality of input/output lines.

10. The apparatus of claim 1, comprising an error code computation unit coupled to a read data register and to a read error code register, the error code computation unit operable to determine if a bit in a plurality of bits read from the memory array and stored in the read data register needs to be corrected based on an error correction code read from the memory array and stored in the read error code register, and to provide the plurality of bits including any corrected bits from the plurality of bits to a corrected data register.

11. The apparatus of claim 10, comprising a data combiner coupled to the corrected data register and to an input data buffer, the corrected data register operable to provide the plurality of bits stored at the corrected data register to the data combiner at about at substantially the same time that the input data buffer at least one of a plurality of data bursts received at the input data buffer to the data combiner.

12. A method comprising:

receiving a plurality of data bursts to be written to a memory array on a corresponding plurality of consecutive clock cycles; and

performing a read/modify/write process for each of the plurality of data bursts within a time period no longer than a period of two cycles of the corresponding plurality of consecutive clock cycles.

13. The method of claim 12, wherein performing the read/modify/write process for each of the plurality of data bursts includes:

determining an address in the memory array to which a particular data burst being processed is to be written; and

reading from the address a plurality of stored data bits.

14. The method of claim 13, wherein performing the read/modify/write process for each of the plurality of data bursts includes:

receiving a data mask associated with the particular data burst being processed; and

providing a modified plurality of data bits by including in the modified plurality of data bits any bits from the plurality of stored data bits for which the data mask has been set, and any bits from the particular data burst being processed for which the data mask has not been set.

15. The method of claim 14, wherein performing the read/modify/write process for each of the plurality of data bursts includes:

generating an error correction code for the modified plurality of data bits.

16. The method of claim 15, wherein performing the read/modify/write process for each of the plurality of data bursts includes:

writing the modified plurality of data bits to the address in the memory array; and

writing the error correction code to the memory array.

17. The method of claim 16, wherein writing the error correction code to the memory array includes:

writing the error correction code to the address in the memory array.

18. The method of claim 16, wherein writing the error correction code to the memory array includes:

writing the error correction code to a different address in the memory array.

19. A method comprising:

receiving a first plurality of data bits following a first clock cycle transition of a plurality of consecutive clock cycle transitions, the first plurality of data bits to be written to at least one portion of a group of data bits stored at a first address in a memory array; and

following the first clock cycle transition and before a third clock cycle transition of the plurality of consecutive clock cycle transitions;

reading at the first address a first group of stored data bits to generate a first group of read data bits;

generating a first group of write data bits by combining the first plurality of data bits with the first group of read data bits;

generating a first error correction code for the first group of write data bits; and

writing the first group of write data bits to the first address.

20. The method of claim 19, comprising:

receiving a second plurality of data bits following a second clock cycle transition of the plurality of consecutive clock cycle transitions, the second plurality of data bits to be written to at least one portion of a group of data bits stored at a second address in the memory array.

21. The method of claim 20, wherein receiving the second plurality of data bits comprises:

following the second clock cycle transition and before a fourth clock cycle transition of the plurality of consecutive clock cycle transitions;

reading at the second address a second group of stored data bits to generate a second group of read data bits;

generating a second group of write data bits by combining the second plurality of data bits with the second group of read data bits;

generating a second error correction code for the second group of write data bits; and

writing the second group of write data bits to the second address.

22. The method of claim 19, wherein reading at the first address comprises:

providing the first address on a plurality of address lines of the memory array; and

receiving at the data buffer the first group of stored data bits provided on a plurality of local input/output lines.

23. The method of claim 22, wherein receiving first group of stored data bits comprises:

gating the first group of stored data bits from the plurality of local input/output lines to a plurality of global input/output lines.

24. The method of claim 19, wherein generating a first group of write data bits comprises:

receiving the first group of read data bits;

receiving an error correction code representing a status of the first group of read data bits at about a time the first group of read data bits was written to the memory array; and

determining if any individual bits included in the first group of read data bits includes an error based on the error correction code representing a status of the first group of read data bits.

25. The method of claim 24, comprises:

correcting an error in any one of a plurality of data bits included in the first group of write data bits.

26. The method of claim 19, wherein generating the first group of write data bits comprises:

receiving a masking input associated with a selected portion of the first group of read data bits; and

masking the first group of write data bits by including in the first group of write data bits the selected portion of the first group of read data bits for which the masking input indicates a masking status has been set.

27. The method of claim 26, comprising:

including in the first group of write data bits a selected portion of the first plurality of data bits for which the masking input indicates that the masking status has not been set.

28. The method of claim 19, wherein generating a first error correction code comprises:

generating a Hamming code based on the first group of write data bits.

29. The method of claim 19, wherein writing the first group of write data bits comprises:

writing a plurality of error correction code bits representing the first error correction code for the first group of write data bits to the first address.

30. The method of claim 19, wherein writing the first group of write data bits comprises:

writing the first error correction code to a first error code address associated with the first address, wherein the first error code address is a different address from the first address.

31. A method comprising:

providing a first data burst during a first clock cycle and providing a second data burst during a second and consecutive clock cycle; and

within a time period no longer than an interval defined by the first clock cycle and the second clock cycle;

providing at a local input/output a first plurality of data bits associated with a wordline and a first plurality of column select lines coupled to an array of memory cells;

gating the first plurality of data bits to a global read input/output from the local input/output;

clearing the first plurality of data bits from the local input/output after gating the first plurality of data bits to the global read input/output;

providing at the local input/output a second plurality of data bits associated with the wordline and a second plurality of column select lines coupled to the array of memory cells;

gating the second plurality of data bits to the global read input/output from the local input/output;

clearing the second plurality of data bits from the local input/output after gating the second plurality of data bits to the global read input/output;

providing a first plurality of write data bits including a plurality of error correction code bits associated with the first plurality of write data bits to a global write input/output; and

writing the first plurality of write data bits including the plurality of error correction code bits to the array of memory cells associated with the wordline and the first plurality of column select lines through the local input/output after clearing the second plurality of data bits from the local input/output.

32. The method of claim 31, wherein the first clock cycle includes a first clock cycle transition and a second clock cycle transition, and wherein the providing of the first plurality of data bits, gating the first plurality of data bits, and clearing the first plurality of data bits occurs during a time period between the first clock cycle transition and the second clock cycle transition.

33. The method of claim 31, wherein the second clock cycle includes a third clock cycle transition and a fourth clock cycle transition, and wherein the providing of the second plurality of data bits, gating the second plurality of data bits, and clearing the second plurality of data bits occurs during a time period between the third clock cycle transition and the fourth clock cycle transition.

34. The method of claim 33, wherein writing the first plurality of write data bits comprises:

during a time period between the fourth clock cycle transition and an end of a second clock cycle transition;

gating the first plurality of write data bits and the plurality of error correction code bits from the global write input/output to the local input/output;

writing the first plurality of data bits and the plurality of error correction code bits to the array of memory cells from the local input/output; and

clearing the first plurality of data bits and the plurality of error correction code bits from the local input/output.

35. A system comprising:

a processor coupled to a memory array, the processor operable to provide a plurality of data bursts to be written to the memory array on a corresponding plurality of consecutive clock cycles, and a data mask for each of the plurality of data bursts; and

an error code module coupled to the processor and to the memory array, the error code module operable to receive the plurality of data bursts and to perform a read/modify/write process for each of the plurality of data bursts within a time period no longer than a period of two cycles of the plurality of consecutive clock cycles.

36. The system of claim 35, wherein the error code module includes:

a plurality of data mask inputs coupled to a data combiner, the plurality of data mask inputs operable to receive the data mask for each of the plurality of data bursts, the data combiner operable to receive individually each one of the plurality of data bursts and to modify each one of the plurality of data bursts to generate a modified data burst based on the data mask for each of the plurality of data bursts.

37. The system of claim 36, wherein the error code module includes:

an error code computation unit coupled to the data combiner, the error code computation unit operable to receive the modified data burst and to provide an error correction code based on the modified data burst.

38. The system of claim 35, including a plurality of input/outputs coupled to the memory array and to the error code module.

39. The system of claim 38, wherein the plurality of input/outputs includes a plurality of local input/outputs coupled to a plurality of addressable groups of memory cells included in the memory array, and wherein each of the plurality of addressable groups of memory cells is coupled to at least one of the plurality of local input/outputs.

40. The system of claim 39, including:

at least one global read input/output coupled to the plurality of local input/outputs and to a read data register included in the error code module, the at least one global read input/output operable to provide a plurality of data bits stored at any one of the plurality of addressable groups of memory cells to the read data register.

41. The system of claim 39, including:

at least one global write input/output coupled to the plurality of local input/outputs and to one or more registers included in the error code module, the at least one global write input/output operable to provide a modified data burst and an error correction code associated with the modified data burst to at least one of the plurality of addressable groups of memory cells.

42. The system of claim 35, wherein the memory array includes a plurality of memory cells and a plurality of wordlines, each one of the plurality of wordlines coupled to a selected group of the plurality of memory cells.

43. The system of claim 35, wherein the error code module includes a data combiner coupled to a data burst register and to a read data register, the data burst register operable to receive the plurality of data bursts, and the read data register coupled to the memory array and operable to receive data stored at an address in the memory array where a selected one of the plurality of data bursts is to be written.

44. The system of claim 35, including:

a clock circuit coupled to the processor and operable to generate the plurality of consecutive clock cycles, and a half-cycle clock generation circuit coupled to the clock circuit and to the error code module, the half-cycle clock generation circuit operable to generate a plurality of consecutive clock cycles at a rate of about twice a rate of the clock circuit.

45. The system of claim 35, wherein the memory array includes dynamic random access memory.

46. The system of claim 35, wherein the memory array is included in a camera.

47. The system of claim 46, wherein the camera is a digital camera.

48. The system of claim 35, wherein the memory array is included in a cell phone.