Asynchronous Gap-Length Optimizing Approach Over IEEE 1394 Serial Bus

摘要

The IEEE 1394 serial bus was designed for digital machines at our homes to deliver realtime stream smoothly. Usually, A/V real-time stream data will be transmitted isochronously and other data are transmitted asynchronously. Isochronous composed of iso and chronous means the same time. That is, after cycle-start packets isochronous transmission will immediately send its packets every cycle. Therefore isochronous transmission has higher priority than asynchronous transmission to send packets. The other side, asynchronous transact ion is suitable for transmitting non-A/V data, especially command packet for control1ing other 1394 devices on the bus or still picture data. Asynchronous packets will be sent only when it is needed. Moreover, it is necessary for responder to return responding packets to requester.