A data processing apparatus includes an input unit to input data and processing modules. The processing modules may be connected as part of a ring-shaped data transfer path to transfer data in one direction. Each processing module includes a communication unit configured to implement a first data processing path and a setting path and a processing unit configured to process data received by the communication unit. When using switching data to switch the processing modules performing on the first data processing path to the processing modules performing on the setting path, the switching data is processed on the first data processing path.