MICROCOMPUTER SYSTEM

摘要

PROBLEM TO BE SOLVED: To immediately diagnose the occurrence of disorder when that disorder is generated in output timing by diagnosing the output of reset signal at that timing within upper and lower limit values designed from an operational abnormality monitor circuit. SOLUTION: A system initializing program includes diagnostic processing for diagnosing the output of reset signal at the timing within the upper and lower limit values designed from 1st and 2nd monitor circuits 2 and 3. Then, the value of reference time predetermined concerning the 1st monitor circuit 2 is designed so as to be settled between the prescribed lower limit value designed while considering a limitation cycle and the prescribed upper limit value determined while considering the allowable runaway time of the program. Similarly, the value of reference time predetermined concerning the 2nd monitor circuit 3 is designed so as to be settled between the prescribed lower limit value designed while considering the time of execution for one instruction and the prescribed upper limit value determined while considering allowable abnormal time.