| 摘要 |
PURPOSE:To decrease the number of hardwares such as parity ROMs, etc. and to realize reduction of cost, by checking the destruction of the ROM, etc. through a CPU and preventing the runaway of program. CONSTITUTION:A CPU41 clears the area of an RAM45 and then carries out a calculation based on a program of a several tens bits within an ROM44 so that the exclusive ORs are turned into horizontal parties in the entire range of the ROM44. After this, the flag showing whether the start time or not within the RAM45 is read out to decide ''start time'' or not. Then the CPU41 calculates the exclusive OR as mentioned above and stores the result of calculation into a register different from that into which the result of the exclusive OR is stored when the system is started. The CPU41 decides the start time or not by referring to the flag showing the start time within the RAM45. |
