DATA TRANSFER DEVICE

PURPOSE: To transfer a large quantity of data while keeping the processing capability when the memory coupling is impossible because of a lack of the address space on the slave side with respect to data transfer between the system of a master MPU and the system of a slave MPU. CONSTITUTION: A memory 3 for communication which consists of a DPRAM and in which the bus of the slave can directly access, a register 14 and an access control part 15 which transmit and receive data to and from a main memory 12 of the master in word units by DMA transfer, and a register 31 for report which reports information related to transfer data on the memory 3 for communication to the destination system are provided. Each time data is communicated between the main memory 12 on the master side and the register 14, the access control part 15 increases the address of the memory 3 for communication to write the data on the register 14 in the address of the memory 3 for communication, and the write is reported to the slave side through the register for report after write of all words.