| 摘要 |
PROBLEM TO BE SOLVED: To provide a user-friendly phase change memory capable of allowing high speed operation.SOLUTION: The phase change memory performs erasure operation and programming operation in n-bit data (M>n) unit when writing M-bit data (8 bit=1 byte), and performs programming operation in n-bit data (M>n) unit when writing M-bit data. When reading M-bit data from a memory cell, the phase change memory performs read operation in n-bit data (M>n) unit. For example, writing into the phase change memory is performed by once placing a target memory cell into an erased state and then performing programming rather than by overwriting data. Data sizes for erasure and programming are set to be equal to each other. Erasure and programming operations are performed only of required data sizes. |
