| 摘要 |
PURPOSE:To surely store the back-up data when the exchange is required between the circuit boards by setting an auxiliary back-up memory on a circuit board different from the one for a main back-up memory. CONSTITUTION:A microprocessor writes simultaneously the same data into a main back-up memory 2 and an auxiliary back-up memory 4 when the back-up information is written. When the back-up information is read out, the microprocessor reads out the contents of the memory 2. In case a printed circuit board 1 has a trouble and is replaced with the new one, the back-up data is transferred to the memory 2 from the memory 4 after a new board 1 is set. Thus the new board 1 can work in the same state as that set before replacement of the board 1 and without erasing the back-up data. |
