| 摘要 |
PURPOSE:To prolong the life of an EAROM by performing writing from the EAROM to a RAM with a source voltage preparation end signal and performing writing from the RAM to the EAROM with a power-off command signal. CONSTITUTION:When the power source is turned on, the source voltage preparation end signal is applied to the RECALL signal terminal of an NVRAM 2 and data is read out of the EAROM 21 and written on the RAM 22. When the power source is turned off, the power-off command signal is applied to the STORE signal terminal of the NVRAM 2 and then the writing from the RAM 22 to the EAROM 21 is carried out. Consequently, the rewriting from the NVRAM 2 to the EAROM 21 is performed as many times as the equipment in use is powered on, i.e. operated, so the possibility that the life of the NVRAM 2 becomes short is eliminated. |
