A device that is capable of generating a new test pattern after the design phase and has a small area of a circuit not in use during normal operation includes a first circuit and a second circuit. The second circuit includes a third circuit and fourth circuit. The fourth circuit has a function of storing data for determining the configuration of the third circuit. When a test for the operating state of the first circuit is performed, the second circuit has a function of generating a signal for the test. When the test is not performed, the second circuit has a function of storing data used for processing in the first circuit and a function of comparing a plurality of signals.