| 摘要 |
PURPOSE:To use an input signal without reference to whether the signal is at an H or an L in the presence of it and at the L or the H in the absence of it, without using an external circuit, by setting or resetting an FF by an instruction. CONSTITUTION:When a power source VDD is negative one, an n type is employed as an MOS transistor TR19, and a p type is used as an MOSTR20. When an input signal is at an H in its presence, an instruction is set holding the real output of an FF30 at the H, and consequently TRs 19 and 20 turn on and off, respectively, so that an input terminal is held at an L when no signal arrives. When the input signal is at the L in its presence, the instruction is set holding the real output of the FF30 at the L, and consequently the TRs 19 and 20 turn off and on, so that the input terminal is at the H when no signal arrives. In a circuit which uses a negative power source VDD, a p type TR19 and an n type TR20 are used. In this case, when the input signal is at the H in its presence, the real output of the FF30 is held at the H and when at the L, its is held at the L. |
