| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase the number of input/output ports which can be programmably used in a microcomputer. SOLUTION: The microcomputer is provided with an invertible amplification circuit 11 which is connected between an oscillation input terminal and an oscillation output terminal, is activated by an oscillation control signal, performs self-biasing and invertible amplification and becomes a high impedance output state at the time of inactive, a delay circuit 12 delaying the pulse trailing edge of an outer reset signal and outputting a delay reset signal, a circuit 13 for pulling down the oscillation output terminal in accordance with a delay reset signal, a flip flop circuit 14 which is reset by the outer reset signal, is set in accordance with the delay reset signal and outputs a detection signal and an input port circuit 15 for gating the signal of the oscillation input terminal by an input port control signal and outputting it as the input port signal of an inner circuit.</p> |
