| 摘要 |
PURPOSE:To quickly apply the occupancy control of a data bus by tying a master module and each slave module by 3 bus occupancy control signal lines and a module address bus. CONSTITUTION:Slave modules 11-1.M output a data bus occupancy request signal to a bus occupancy request signal line BR to occupy the data bus DB to a master module 10, gives its own address to a module address bus MAB, receives an acknowledge signal from the master module through a bus occupancy request reply signal line BA, and when a monitor means of the slave module detects address information other than its own address, a signal cancelling the occupancy request of the data bus is outputted from a bus occupancy request cancel signal lien BC. Thus, only a bus occupancy request from a sole slave module is received and the bus occupancy request and the designation of the opposite module are applied simultaneously, then the occupancy procedure is finished in a short time.
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