| 摘要 |
PURPOSE:To obtain a device for wide use which can select a daisy chain system as well as a parallel system, by providing a switching circuit in the front stage where a signal indicating that a module acquires a bus is inputted to every module. CONSTITUTION:A device requiring the bus priority control where plural modules 3a-3d are connected to a bus is provided with controlling circuits for a daisy chain system and a parallel system so that the priority control is possible in both systems. A switching circuit 3f is provided in the front stage, through which signals IN and ACK indicating the acquisition of the bus are inputted to modules 3a-3d to be connected to the bus, to select either system. For example, in the parallel system, an output signal REQ requests the bus to a priority determining circuit 2e; and in the daisy chain system, information indicating that one module requests the bus is transmitted with an output signal OUT from this module to the module whose priority is one level below. |
