| 摘要 |
PURPOSE:To recognize the mounting state of an optional unit, by providing a pull-up or down resistance and a state monitoring flip flop to make it possible to use a non-optional unit as the optional unit. CONSTITUTION:A reset signal is inputted from the input terminal 51 of the optional unit 5 to an internal circuit 50. One of outputs of the internal circuit 50 is supplied to an output terminal 52 as the second signal, and the output terminal 52 is connected to the input terminal 54 of a unit 6 and the input terminal 57 of a non-optional unit 7. The input terminal 57 is connected to a power supply terminal VCC through the data input terminal D of the internal D type flip flop 55 of the non-optional unit 7 and a pull-up resistance 56. Further, a reset signal line 150 is connected from the input terminal 58 of the non-optional unit 7 to the clock input terminal CP of the flip flop 55. |
