| 摘要 |
PURPOSE:To inexpensively hold the switching state with a high reliability by providing an EEPROM and comparing an inputted switching control signal with the just preceding switching state to store the latest switching state. CONSTITUTION:When noncoincidence between the switching control signal inputted from a terminal A and the output of a latch circuit 4 indicating the present switching state is detected by a coincidence deciding circuit 1, a sequencer circuit 2 enables a gate circuit 5 and sends a write signal to an EEPROM 3. The new switching state is stored in the EEPROM 3. Next, the sequencer circuit 2 disables the gate circuit 5 and electrically holds data of the EEPROM 3 in the latch circuit 4. At the time of restoration from a power failure, the sequencer circuit 2 disables the gate circuit 5 and sends a read signal to the EEPROM 3. Data from the EEPROM 3 is electrically held in the latch circuit 4. |
