| 摘要 |
PURPOSE:To reduce the number of lines in the bus and to decrease noise and shorting between lines by providing a common audio unit and a display unit for plural source units such as units for a vehicle and omitting a signal line TX/RX that detects a state in communication and the end of communication. CONSTITUTION:An operation unit 1, a display unit 2, a deck unit 3, a tuner unit 4 and an audio unit are connected through a common bus 6 to enable mutual communication. To perform data communication between units using the common bus 6 one of 0-15 addresses is allotted to each unit. When transmitting, the addresses of transmitting side and receiving side are sent first, then the data length to be sent is sent expressing it in the number of bytes (n). Thereafter, data 1- data (n) are sent, and the transmission is completed when (n) byte of data are transmitted. On the other hand, when receiving, the unit of receiving side counts the number of data, and receiving is terminated when the counted value becomes the number of data sent at the beginning of communication. |
