| 摘要 |
PURPOSE:To accurately detect the runaway of a processor even at execution of a program including a branch instruction by sending a reset signal to a processor when no coincidence is obtained between the output data on a latch circuit and the data held by a register. CONSTITUTION:A latch circuit 7 latches a prescribed address when the prescribed address data is outputted from an MPU 1 and detected by a decoder 4 and at the same time a read/write signal WR is outputted from the MPU 1. A register 8 fetches and holds the data outputted from the MPU 1 when the latch conditions are satisfied to the circuit 7. Then a comparator 9 compares the output of the circuit 7 with that of the register 8 and applies a reset signal of an L level and a reset signal of an H level to a terminal NMI of the MPU 1 when the coincidence and no coincidence are obtained between both outputs respectively. Thus it is possible to accurately detect the runaway of a processor even at execution of a program including a branch instruction. |
