Memory controller, memory system, semiconductor integrated circuit, and memory control method

A memory system comprising a memory and a memory controller, said memory storing image data and being accessed in burst mode at a burst length of N where N is an integer number of two or more,

• wherein said memory includes:
• a first group including a plurality of banks;
• a second group including a plurality of banks;
• and
• a prefetch buffer of N bits,
• said prefetch buffer includes a first operating mode where N-bit data is prefetched from one of said plurality of banks and a second operating mode where N/2-bit data is prefetched from each of two banks belonging to different groups,
• said memory controller includes
• a command generation unit configured to generate a plurality of access commands each including a physical address, based on an access request including a logical address indicating a rectangular area in the image data;
• and
• a command issuance unit configured to issue, to said memory, the plurality of access commands generated by said command generation unit,
• said command generation unit includes a group determination unit configured to determine whether or not data to be accessed is continuous across two banks belonging to different groups,
• said command generation unit is configured to generate the plurality of access commands including a first access command and a second access command based on the determination made by said group determination unit,
• the first access command is a command for accessing to a bank belonging to the first group, using a half of said prefetch buffer, and
• the second access command is a command for accessing to a bank belonging to the second group, using a remaining half of said prefetch buffer, the second access command sharing said prefetch buffer with the first access command.

A memory control method for controlling access to a memory including a first group, a second group, and a prefetch buffer of N bits (where N is an integer number of two or more), each of the first group and the second group including a plurality of banks, the memory storing an image data and being accessed in burst mode at a burst length of N, said memory control method comprising:

• generating a plurality of access commands each including a physical address, based on an access request including a logical address indicating a rectangular area in the image data;
• and
• issuing, to the memory, the plurality of access commands generated in said generating,
• wherein, in said generating, it is determined whether or not data to be accessed is continuous across two banks belonging to different groups, based on the physical address corresponding to the access request, and generating a first access command and a second access command based on the determination,
• the first access command is a command for accessing to a bank belonging to the first group, using a half of the prefetch buffer, and
• the second access command is a command for accessing to a bank belonging to the second group, using a remaining half of the prefetch buffer, the second access command sharing the prefetch buffer with the first access command.