| 摘要 |
PURPOSE:To detect assuredly a program runaway by comparing an execution address signal with an address signal of a memory which is read out synchronously with said execution address signal. CONSTITUTION:The address signal which shows the procedure of an information processing program detected previously is written to an external ROM2 after said processing program written to a ROM incorporated to a microcomputer muCOM. The address signal read out of the ROM2 is fetched temporarily by a latch circuit FF. The address signal of the ROM2 which is delayed by a cycle by the circuit FF is compared with the execution address signal of the muCOM through a coincidence/discordance circuit EX consisting of an exclusive OR circuit, etc. Thus it is checked whether a program is executed according to its procedure or not. Then the runaway of the program is detected by the discordance output. |
