BREAK SIGNAL GENERATOR

PURPOSE:To select the validity or invalidity for operation of a break key through a loading part in response to the program contents of a memory module, by controlling the break signal sent from the break key through a gate circuit in response to the selecting state of a selection circuit. CONSTITUTION:An AND circuit 5 serving as a gate circuit is set to a route of a break signal generated with push of a break key 1 via a waveform shaping Schmitt circuit 6. An input terminal at the other side of the circuit 5 is extended up to a loading part 2 where a memory module is loaded. The part 2 contains a selection switch 4 which decides the validity or invalidity for operation of the key 1. Therefore the break signal is supplied to a PB terminal of an I/O port 7 if a high level VGG is selected at the part 2. While the output of the circuit 5 is cut off regardless of the presence or absence of the break signal if a low level GND is selected at the part 2. Thus no break signal is detected by the port 7.