| 摘要 |
PURPOSE:To provide the memory protecting device which protects processing data saved in the RAM of a microprocessor and also prevents the microprocessor from running away even when electric power is supplied. CONSTITUTION:The memory protecting device consisting of a power source detecting circuit 1 which detects the supply state of a supply power source and outputs a signal if its power supply is broken, an MPU 3 which processes externally inputted data, a RAM 2 which stores the data processed by the MPU 3 when the power source detecting circuit 1 detects the break of the power supply, and a battery power source 5 which supplies electric power to the RAM 2 when the power source detecting circuit 1 detects the break of the power supply is equipped with a delay circuit 6 which delays the operation for storing the data processed by the MPU 3 in the RAM 2 by a certain time when the power source detecting circuit 1 detects the break of the power supply, and a NAND circuit 7. |
