DATA TRANSFER DEVICE OF MICROCOMPUTER

摘要

PROBLEM TO BE SOLVED: To specify a memory address fast by an external device when memory data of the microcomputer are transferred to the external device by an SPI communication. SOLUTION: The microcomputer 11 has a clock synchronous serial communication (SPI communication) with a tool 12 for adaptation through a serial interface 13. A high-order address specification register 24 of the microcomputer 11 specifies the high-order address of data which desires to be read out of a RAM 27. An address generation circuit 25 combines serial data (low-order address) sent from the tool 12 for adaptation with the high-order address specified by the high-order address specification register 24 to generate the address of RAM data to be sent next. Then a transmit data transfer circuit 26 reads the RAM address in the address by direct memory access, and transfers them to a transmit data buffer register 20, so that the data are transmitted to the tool 12 for adaptation.