Abstract: The present invention provides an input/output device capable of bringing a per-unit input/output circuit into a simple configuration without impairing reliability even when logic levels opposite in polarity are outputted between input/output devices made conductive to the outside. The input/output device is equipped with one reference port Pk selected from a port group which inputs and outputs signals, target ports Pt selected from other than the reference port of the port group, and a conduction detector which detects that conduction is made between input/output terminals for the reference port Pk and the target ports Pt.

Abstract: The present invention provides an input/output device capable of bringing a per-unit input/output circuit into a simple configuration without impairing reliability even when logic levels opposite in polarity are outputted between input/output devices made conductive to the outside. The input/output device is equipped with one reference port Pk selected from a port group which inputs and outputs signals, target ports Pt selected from other than the reference port of the port group, and a conduction detector which detects that conduction is made between input/output terminals for the reference port Pk and the target ports Pt.

Abstract: A first level converter is provided with an input transistor circuit and an output transistor circuit. The input transistor circuit is supplied with power from a first power source and outputs a complementary signal on the basis of an input signal. The output transistor circuit is supplied with power from a second power source, and amplifies and outputs the complementary signal. A second level converter is provided with a pulse generating circuit and a signal output circuit. The pulse generating circuit is supplied with power from the first driving power source, and generates a one-shot pulse signal. The signal output circuit is supplied with power from the second driving power source, latches the one-shot pulse signal and outputs the signal. The semiconductor integrated circuit is provided with a first circuit system, a level conversion circuit and a second circuit system. The first circuit system is driven by being supplied with power from the first driving power source.