Memory system for access concentration decrease management and access concentration decrease method
A spatial disturbance that occurs when an access is concentrated in a specific memory area in a volatile semiconductor memory like DRAM is properly solved by a memory controller. The memory controller includes a concentration access detection part generating a concentration access detection signal when an address for accessing a specific memory area among memory areas of volatile semiconductor memory is concentratedly received. In the case that the concentration access detection signal is generated, the memory controller includes a controller for easing or preventing corruption of data which memory cells of the specific memory area and/or memory cells of memory areas adjacent to the specific memory area hold.
1. A memory controller comprising:
a concentration access detector configured to generate a concentration access detection signal in response to a first address corresponding to a first word line connected to a first set of memory cells of a dynamic random access memory (DRAM) device being accessed a number of access instances that exceeds a threshold number within a predetermined period of time;
a controller configured to, in response to the concentration access detection signal being generated, swap the first address with a second address corresponding to a second word line connected to a second set of memory cells of the memory device such that the second word line is selected when the first address is subsequently accessed, and swap the second address with the first address corresponding to the first word line connected to the first set of memory cells of the memory device such that the first word line is selected when the second address is subsequently accessed; and
a substitution buffer configured to, in response to the concentration access detection signal is generated, store first data stored in the first set of memory cells and second data stored in the second set of memory cells,
wherein the controller is configured to, in response to the concentration access detection signal being generated, store the first data in the second set of memory cells and store the second data in the first set of memory cells using the substitution buffer.
2. The memory controller of claim 1 , further comprising:
an internal register configured to store the generated concentration access detection signal.
3. The memory controller of claim 1 , wherein the first set of memory cells corresponds to a row of the DRAM.
4. The method of claim 1 , wherein the concentration access detection signal is generated whenever the first address is accessed 50,000 or more times during the predetermined period of time.
5. The memory controller of claim 1 , wherein the first address is a row address.
6. An operating method of a memory controller, the operating method comprising:
checking whether a first address corresponding to a first word line connected to a first set of memory cells of a dynamic random access memory (DRAM) device is concentratedly accessed;
generating a concentration access detection signal in response to the first address being accessed a number of access instances that exceeds a threshold number within a predetermined period of time;
swapping the first address with a second address corresponding to a second word line connected to a second set of memory cells of the memory device in response to the concentration access detection signal being generated such that the second word line is selected when the first address is subsequently accessed;
swapping the second address with the first address corresponding to the first word line connected to the first set of memory cells of the memory device in response to the concentration access detection signal being generated such that the first word line is selected when the second address is subsequently accessed; and
in response to the concentration access detection signal being generated, store first data of the first set of memory cells in the second set of memory cells and store second data of the second set of memory cells in the first set of memory cells using a substitution buffer.
7. The operating method of claim 6 , further comprising:
storing the generated concentration access detection signal in an internal register of the memory controller.
8. The method of claim 6 , wherein the concentration access detection signal is generated whenever the first address is accessed 50,000 or more times during the predetermined period of time.
9. The method of claim 6 , wherein the first address is a row address.