| 摘要 |
PURPOSE:To prevent the intermission of a control output at reset processing by switching a signal to a fixed control signal at the runaway of a microcomputer and selecting a control signal of the microcomputer when the operation is restored to normal operation. CONSTITUTION:If the microcomputer 1 runs away and generation of a pulse signal A is intermitted, an output signal B of a dead man timer 3 goes to H, a flip-flop circuit 13 is set and a changeover circuit 7 selects and outputs the fixed control signal generated from a fixed output circuit 6. On the other hand, while the output signal B is generated, a reset circuit 4 generates a reset pulse C at each prescribed period and the pulse C is fed to a reset input terminal R. When the state is restored to the normal stage by the reset processing, the output signal B is inverted to L, the time count of a timer 11 is started and when the time reaches a preset time, a flip-flop 13 is reset and the changeover circuit 7 selects the control signal generated from the microcomputer 1. |
