| 摘要 |
PURPOSE:To prevent the damage of a memory device in such a case a CPU is in runaway state due to a malfunction and executes a program kept in an unused area of the memory by storing a processing program in the memory unused area against the runaway of the CPU. CONSTITUTION:A program 1 is stored in the addresses '0000H' - '5FFFH' of an EPROM, and a processing program is stored in the addresses '6000H' - '7FFFH' against the runaway of a CPU. In a normal working state the CPU executes the program stored in the addresses '0000H' - '5FFFH'. However the CPU has a malfunction by some factor and executes the program stored in the addresses '6000H' - '7FFFH'. In such a case, the processing is executed to the CPU runaway since the due program is stored in said addresses. Thus it is possible to prevent the damage of a memory device in such a case the CPU is in runaway state and uses a program stored in an unused area of the memory. |
