A data processing apparatus may include a buffer unit, a data write control unit, a data read control unit, and a buffer area determination unit. The data write control unit may write the input data to the storage area determined by the buffer area determination unit, and output a data write completion signal indicating that the writing of the data is completed when the writing of the input data is completed. The data read control unit may read the data from the storage area determined by the buffer area determination unit, and output a data read completion signal indicating that the reading of the data is completed when the output of the output data generated based on the read data is completed.