PURPOSE: To perform the transfer of data at a high speed and a high degree of freedom by supplying data directly to a RAM of a digital signal processing part from outside with DMA transfer.

CONSTITUTION: An address terminal 10 serves as an input terminal through which the address of a RAM4 is supplied when data are supplied to the RAM4 of a DSP (digital signal processing) part from outside, then serves as an output terminal through which the address of an external memory is supplied when the DSP part delivers data to an external memory. A data terminal 1 serves as the input and output terminals of the DSP part and the external memory like the terminal 10. An I/O control part 6 controls the way of transfer of data to outside, and a program control part 5 controls a program for operations of the DSP part. The part 5 also stops the execution of the program with a program stop signal of a DMA mode sent from the part 6 and functions to deliver up an internal bus and the RAM to a DMA action.