There is achieved a high-integrated and high-speed nonvolatile memory
which can stabilize an operation of a phase-change memory for a short
operation cycle time. A latch is provided in a write driver. A change to
a high-resistance state of a phase-change element is performed per column
cycle by a write-enable signal, and a change to a low-resistance state
thereof is performed after a pre-charge command is inputted and
concurrently with deactivation of a pre-charge signal. Thereby, a write
time to a memory cell in which phase-change resistance is changed to a
low-resistance state, and a period from a write operation for changing
the phase-change resistance to a high-resistance state to a read
operation to the above memory cell can be lengthened without extending
the column cycle time, so that the stable write operation is achieved.