To include one or a plurality of internal signal lines that electrically connects an interface chip to a core chip. The interface chip includes a first circuit that outputs a current to an internal wiring and the core chip includes a second circuit that outputs a current to the first internal signal line. The interface chip includes a determination circuit that has a first input terminal connected to the internal wiring through which the current outputted by the first circuit flows and a second input terminal connected to an end of the first internal signal line in the interface chip, and outputs a voltage according to a potential difference between a voltage of the first input terminal and a voltage of the second input terminal.