| 摘要 |
PURPOSE: To lengthen a lifetime of a non-volatile memory and to know the number of times of writing in a non-volatile memory by providing a volatile memory circuit section holding temporarily a rewritten data part, a writing detecting circuit holding the number of times of writing of data for a non- volatile memory circuit section and the like. CONSTITUTION: A rewritten data part for a non-volatile memory circuit section 22 being a main memory is held in a volatile memory circuit section 21 temporarily. And after data to be written in the circuit section 21 is decide, data of the circuit 21 is written in the circuit section 22, the number of times of writing for the circuit 22 is reduced, a lifetime of the non-volatile memory circuit section is practically extended. On the other hand, a writing detecting circuit 23 counts and stores the number of times of writing for the circuit section 22, writes the number of times of writing in the circuit section 22 at the time of turning off a power supply, and an operator can always know the number of times of writing of the circuit section 22. |
