| 摘要 |
PURPOSE:To avoid a wrong writing operation to an area of a memory by checking the writing instruction to the area of the memory which stores an operating system, etc., written at the time of a rise state. CONSTITUTION:In an initialization state where an operating system, etc., are stored in a memory, a writing instruction is delivered to designate an area where the operating system, etc., of the memory device are stored for a period during which the initialization is through after the power supply of the memory is switched on. Thus a writing control means 5 outputs a write enable signal 15 so that a writing operation is possible for initialization even in case a write inhibiting signal is supplied to the means 5 from an area guard means 3. When the initialization is through, the means 5 detects an error signal to prevent a wrong writing operation into said area in case the write inhibiting signal is received from the means 3 to the area. Thus the system breakdown can be avoided. |
