A semiconductor apparatus of the present invention includes a first to a fourth external terminals and a decoding circuit. The semiconductor apparatus in a first mode inputs a first encoded data from the first external terminal, decodes the first encoded data by the decoding circuit to generate a first decoded data, outputs the first decoded data from the fourth external terminal, and the semiconductor apparatus in a second mode, inputs a second encoded data from the first external terminal, outputs the second encoded data input from the first external terminal from the second external terminal, inputs the second encoded data output from the second external terminal from the third external terminal, decodes the second encoded data input from the third external terminal by the decoding circuit to generate a second decoded data and outputs the second decoded data from the fourth external terminal.