| 摘要 |
PURPOSE:To quickly detect a runaway of a CPU, to minimize its damage, and to reset it to a normal operation by detecting an abnormality of the CPU, when a latch data and a fixed data have coincided continuously by a prescribed number of times. CONSTITUTION:When a CPU 11 designates an address and sends out a program data to a bus 13 from a ROM 14 or a RAM 15, a latching circuit 18 latches a data K on the bus 13 by its read-out timing signal M and sends it to a comparing part 20. The comparing part 20 compares the data K and a fixed data of a storage part 19, and sends a signal S to a counting part 21, when they have coincided. In the counting part 21, when the signal S has been counted continuously by a prescribed number of times at every input of the signal M, an interrupting signal I is sent to the CPU 11, by which the CPU 11 allows a program to jump to a routine for processing an abnormality. |
