MALFUNCTION DETECTING DEVICE FOR ELECTRONIC CIRCUIT

摘要

PURPOSE:To minimize the effect to be applied to the peripheral units when the electronic circuit has some defect or malfunction by resetting the electronic circuit to the original period with detection of the fact that the time of the step passage exceeds the fixed value. CONSTITUTION:Shift register 23 of malfunction detecting device 2 possesses the function of the counter which counts the time determined by the number of the bit cell and the period oc clock signal 15. When microcomputer 11 has malfunction and a certain bit of output signal 14 becomes ''H'' continuously, the output of NOR gate 21 becomes ''L'' and ''H'' is given continuously to register 23 after inversion 22. After a fixed time, register 23 turns all of its output to high level, thus AND gate 24 detects the fact that each output has all become ''H'' to give the ''H'' signals to computer 11. Thus computer 11 returns to the original state to continue the normal operation based on the program.