Data writing method, memory controller, and memory storage device

A memory storage device, comprising:

• a connector, configured to couple to a host system;
• a rewritable non-volatile memory module, comprising a plurality of physical erasing units, wherein each of the physical erasing units comprises a plurality of physical programming units, and the physical erasing units are grouped into at least a data area;
• and a memory controller, coupled to the connector and the rewritable non-volatile memory module, wherein the memory controller is configured to configure a plurality of logical addresses to map to the physical erasing units in the data area, group at least one physical erasing unit among the physical erasing units besides the physical erasing units in the data area into a first buffer area, and group at least one physical erasing unit among the physical erasing units besides the physical erasing units in the data area into a second buffer area, wherein the at least one physical erasing unit of the first buffer area is different from the at least one physical erasing unit of the second buffer area,
• wherein the memory controller is configured to receive a first write command, wherein the first write command instructs to write a first data to a first logical address among the logical addresses, and the memory controller determines whether a quantity of the first data is smaller than a predetermined value,
• if the quantity of the first data is smaller than the predetermined value, the memory controller is configured to write the first data into the at least one physical erasing unit of the first buffer area or the at least one physical erasing unit of the second buffer area,
• if the memory controller writes the first data into the at least one second physical erasing unit of the second buffer area, the memory controller is configured to obtain at least one second logical address mapped to at least one first physical programing unit in the at least one physical erasing unit of the first buffer area and copy valid data belonging to the at least one second logical address into a third physical erasing unit among the physical erasing units, wherein the number of the at least one second logical address is smaller than a merging threshold number and the third physical erasing unit is different from the at least one physical erasing unit of the first buffer area and the at least one physical erasing unit of the second buffer area.

A memory controller, for controlling a rewritable non-volatile memory module, the memory controller comprising:

• a host interface, configured to couple to a host system;
• a memory interface, configured to couple to the rewritable non-volatile memory module, wherein the rewritable non-volatile memory module comprises a plurality of physical erasing units, each of the physical erasing units comprises a plurality of physical programing units, and the physical erasing units are grouped into at least a data area;
• and a memory management circuit, coupled to the host interface and the memory interface, wherein the memory management circuit is configured to configure a plurality of logical addresses to map to the physical erasing units in the data area, group at least one physical erasing unit among the physical erasing units besides the physical erasing units in the data area into a first buffer area, and group at least one physical erasing unit among the physical erasing units besides the physical erasing units in the data area into a second buffer area, wherein the at least one physical erasing unit of the first buffer area is different from the at least one physical erasing unit of the second buffer area, wherein the memory management circuit is configured to receive a first write command, wherein the first write command instructs to write a first data to a first logical address among the logical addresses, and the memory management circuit is configured to determine whether a quantity of the first data is smaller than a predetermined value,
• if the quantity of the first data is smaller than the predetermined value, memory management circuit is configured to write the first data into the at least one physical erasing unit of the first buffer area or the at least one physical erasing unit of the second buffer area,
• if the memory management circuit writes the first data into the at least one physical erasing unit of the second buffer area, the memory management circuit obtains at least one second logical address mapped to at least one first physical programing unit in the at least one physical erasing unit of the first buffer area and copies merges valid data belonging to the at least one second logical address into a third physical erasing unit among the physical erasing units, wherein the number of the at least one second logical address is smaller than a merging threshold number and the third physical erasing unit is different from the at least one physical erasing unit of the first buffer area and the at least one physical erasing unit of the second buffer area.