| 摘要 |
PURPOSE:To shorten the time required with a composite bus system to decide the right to use a bus by providing a dedicated priority decision circuit to a slave bus. CONSTITUTION:The priority decision circuit consisting of an encoder EC and a decoder DC is provided in a bus extending circuit BA2' provided to the slave bus BUS2, each bus request signal R' from each device connected to the slave bus BUS2 is transmitted to the encoder, and a bus priority input signal P' is sent from the decoder DC to each device. The encoder EC transmits a couple of bus request signals to the priority decision circuit PR provided to a main bus BUS1 in common to all transmitted bus request signals R'. The bus priority input signal P send by the PR for this bus request signal R is transmitted to the decoder DC and converted into a bus priority input signal P' for the selected device on the basis of specific priority. |
