WE CLAIM:
1. A memory controller (110) comprising:
read logic to read a voltage value of a memory cell (112) in a cross-point non-volatile memory (104) having a plurality of memory cells, wherein the plurality of memory cells have voltage values respectively set to a first threshold voltage or a second threshold voltage; and
write logic coupled with the read logic (120) and to refresh the voltage value of a first one or more of the plurality of memory cells set to the second threshold voltage without altering the voltage value of a second one or more of the plurality of memory cells set to the first threshold voltage;
wherein the write logic (120) is to
perform a write operation, in response to a detection that an error count of a third one or more memory cells of the plurality of memory cells exceeds an error threshold, to reset the respective voltage values of each memory cell in the third one or more memory cells to the first threshold voltage if the memory cell is set to the first threshold voltage; and
perform a write operation, in response to the detection, to reset the respective voltage values of each memory cell in the third one or more memory cells to the second threshold voltage if the memory cell is set to the second threshold voltage.
2. The memory controller as claimed in claim 1, wherein the second
threshold voltage is higher than the first threshold voltage.
3. The memory controller as claimed in claim 1, wherein the cross-
point non-volatile memory is a phase-change memory (PCM).
. The memory controller as claimed in claim 1, wherein the write logic is to perform a write operation to re-set the voltage value of each memory cell in the first one or more of the plurality of memory cells to the second threshold voltage to refresh the voltage value of the first one or more of the plurality of memory cells.5. The memory controller as claimed in claim 1, wherein the read logic is to refresh the voltage value of the second one or more of the plurality of memory cells by a comparison of the

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voltage value of each memory cell in the second one or more of the plurality of memory cells to a reference voltage.
6. The memory controller as claimed in claim 5, wherein the reference voltage is greater than the first threshold voltage value and less than the second threshold voltage value.
7. The memory controller as claimed in claim 1, comprising error correction logic coupled with the read logic and the write logic, the error correction logic to:
identify the third one or more memory cells of the plurality of memory cells as having produced an error upon a read of the voltage value of the third one or more memory cells by the read logic; and
detect whether the count of the third one or more memory cells of the plurality of memory cells exceed the error threshold.
8. A method comprising:
refreshing, by a memory controller, a first voltage value of a first memory cell in a cross-point non-volatile memory including a plurality of memory cells respectively having a voltage value set to a first threshold voltage or a second threshold voltage, the first voltage value of the first memory cell set to the first threshold voltage, and wherein the refreshing includes comparing the first voltage value of the first memory cell to a reference voltage; detecting, by the memory controller and after the refreshing, one or more memory cells in the plurality of memory cells that produce an error upon reading respective voltage values of the one or more memory cells;
comparing, by the memory controller (110), a number of the one or more memory cells with an error threshold value; and
refreshing, by the memory controller if the number of the one or more memory cells is less than the error threshold value, a second voltage value of a second memory cell in the cross-point non-volatile memory by re-writing the second threshold voltage to the second memory cell without altering the first voltage value of the first memory cell.
9. The method as claimed in claim 8, comprising:

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refreshing, by the memory controller if the number of the one or more memory cells is greater than the error threshold value, the first voltage value of the first memory cell by re-writing the first threshold voltage to the first memory cell.
10. The method as claimed in claim 8, wherein the first threshold voltage is less than the second threshold voltage.
11. The method as claimed in claim 8, wherein the reference voltage is greater than the first threshold voltage value.
12. The method as claimed in claim 8, wherein the cross-point non-volatile memory is a phase-change memory (PCM).
13. One or more non-transitory computer readable media comprising instructions to, upon execution of the instructions by a memory controller (110) of the computing device (600), cause the memory controller to:
refresh a first voltage value of a first memory cell in a cross-point non-volatile memory including a plurality of memory cells set to a first threshold voltage or a second threshold voltage, wherein the refresh includes a comparison of the first voltage value of the first memory cell to a reference voltage;
refresh a second voltage value of a second memory cell in the cross-point non-volatile memory by re-writing the second threshold voltage to the second memory cell; and
refresh, if a number of detected errors of the one or more memory cells is greater than an error threshold value, the respective voltage value of the one or more memory cells, wherein the refresh of the respective voltage value of the one or more memory cells includes:
re-write the first threshold voltage to a first subset of memory cells in the one or more memory cells that are set to the first threshold voltage; and
re-write the second threshold voltage to a second subset of memory cells in the one or more memory cells that are set to the second threshold voltage.

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14. The one or more non-transitory computer readable media as
claimed in claim 13, wherein the instructions are to cause the memory
controller to:
detect, subsequent to the refresh of the first voltage value and the refresh of the second voltage value, whether one or more memory cells in the plurality of memory cells produce an error upon a read of a respective voltage value of the one or more memory cells; and
compare a number of the one or more memory cells with an error threshold value.
15. The one or more non-transitory computer1 readable media as claimed in claim 13, wherein the first threshold voltage value is less than the second threshold voltage value.
16. The one or more non-transitory computer readable media as claimed in claim 13, wherein the reference voltage is greater than the first threshold voltage value.
17. The one or more non-transitory computer readable media as claimed in claim 13, wherein the cross-point non-volatile memory is a phase-change memory (PCM).
Dated this 28th Day of August 2019
(P. Dileep Kumar) Registration Number: IN/PA-13 64 For Law Firm of Naren Thappeta Agent for Applicant

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