An integrated circuit includes: a signal processor, which receives an input signal and generates a processed signal, representing processing information obtained by subjecting the input signal to predetermined processing, and at least one type of internal signal including internal information obtained during the processing; at least one memory storing the processing information; an interface exchanges signals with an external device; and a controller controlling the signal processor, memory and interface. On receiving a first instruction from the external device through the interface, the controller controls the signal processor and memory such that the processing information is once stored in the memory and then output to the external device via the interface. In response to a second instruction, the controller controls the signal processor and memory such that the internal information is once stored in the memory and then output to the external device via the interface.