Memory controller, control method for the memory controller, and control method for memory

A control method for a memory controller which accesses a memory comprising a plurality of memory blocks, comprising:

• determining whether a refresh request is issued;
• when the refresh request is issued, a refresh value is read to select a specific memory block among the memory blocks;
• reading a data table to determine whether the specific memory block stores valid data;
• sending a refresh command to the memory and, after a first waiting time, accessing the memory when the specific memory block stores valid data;
• sending the refresh command to the memory and, after a second waiting time, accessing the memory when the specific memory block does not store any data or stores invalid data;
• and
• updating the refresh value,
• wherein the second waiting time is shorter than the first waiting time.

A memory coupled to a memory controller, comprising:

• a plurality of memory blocks configured to store data;
• a storage circuit storing a first refresh value and a first data table;
• and
• a control circuit accessing the memory blocks and updating the first data table, wherein the first data table comprises a plurality of bits, and each bit indicates whether a corresponding memory block stores valid data,
• wherein when the control circuit receives a refresh command, the control circuit selects a specific memory block among the memory blocks according to the first refresh value and determines whether the specific memory block stores valid data according to the first data table,
• wherein when the specific memory block stores valid data, the control circuit refreshes the specific memory block, and
• wherein when the specific memory block does not store any data or stores invalid data, the control circuit does not refresh the specific memory block.

A control method for a memory which comprises a plurality of memory blocks and is controlled by a memory controller, comprising:

• determining whether a refresh command is sent from the memory controller, wherein when a refresh command is sent from the memory controller, a refresh value is read to select a specific memory block among the memory blocks;
• reading a data table to determine whether the specific memory block stores valid data, wherein when the specific memory block stores valid data, the specific memory block is refreshed, and when the specific memory block does not store any data or stores invalid data, the specific memory block is not refreshed;
• and
• updating the refresh value after the refresh value is read.