DATA TRANSMISSION SYSTEM AND DATA TRANSMISSION METHOD

摘要

Before transmitting one or more data packets, the data portions of which include data to be transferred, to another device, a transmission unit (12) of a first device (A) transmits a first packet, for notifying that use of a serial bus has begun, to a second device (B). The second device (B) is provided with a flag register (34) which stores a bus usage flag expressing the usage state of the serial bus. A reception unit (18) of the second device (B), upon receiving the first packet, sets the bus usage flag to "in use", and a transmission unit (16) transmits data packets to that other device only when the bus usage flag is not set to "in use".