| 摘要 |
<p>PURPOSE:To detect the run-away of a program and to execute the system resetting by periodically resetting a watch dog timer and comparing the output of a program ROM with the output of a monitor RAM. CONSTITUTION:A program ROM 119 resets periodically a watch dog timer 105 and when the timer resetting after the second resetting occurs, a monitor RAM 114 outputs the previously read instruction. A comparator 110 compares the instruction outputs of the ROM 119 with that of the RAM 114 and when the uncoincidence is detected, an uncoincidence output 112 is outputted after the second resetting as it is. Consequently, the output 112 resets a system resetting circuit 102 through a logical gate 103 together with an overflowing output 104 of a timer 105 as an output 107 of a logical gate 111. Thus, the run-away generation of the program is detected and the system resetting can be executed.</p> |
