| 摘要 |
PROBLEM TO BE SOLVED: To surely hold data at no operation by a smaller circuit scale in a 1-chip microcomputer obtained by integrating a CPU and a memory for storing data. SOLUTION: In writing operation, for example, a voltage detection circuit 14 detects that power source voltage from a power source circuit 11 drops to power interruption voltage. Then, the circuit 14 varies the level of a voltage detection signal (d) to be outputted to a writing/reading control circuit 15. Then, at the timing of the break of a data bus 17, the circuit 15 stops the output of writing control signal (c) to a ferroelectric memory 21. Thus, data in the middle of being written is prevented from being written in the memory 21 as uncertain data. |
