1. An encoding/decoding device for compressing or expanding digital data, comprising: a DSP processor for compressing or expanding the digital data; a nonvolatile memory in which compressed program data and compressed parameter data are stored; a volatile memory for temporarily storing the program data and the parameter data; and a general-purpose processor for controlling a system, wherein the general-purpose processor expands the compressed program data and the compressed parameter data and transmits them to the volatile memory, and the DSP processor reads the expanded program data and the expanded parameter data into an internal memory of the DSP processor and compresses or expands the digital data on the basis of the program data and the parameter data.