| 摘要 |
PURPOSE: A common bus buffer circuit is provided to confirm trouble-occurring conditions by separating common buses and employing a multiplexer for confirming the trouble-occurring conditions of buffers. CONSTITUTION: Local common buses(70,80) are connected to a control unit(10), a RAM(30) and ROM(20), and transits address and data signals. External common buses(120,130) are connected to external connector units(40,50,60), and transmit the address and data signals. A connector buffer(140) is connected between the local common buses(70,80) and the external common buses(120,130), and connects or separates the common buses in response to control signals. A pattern generator(100) outputs test pattern signals for inspecting trouble-occurring conditions of the common buses(70,80;120,130) in response to the control signals. A multiplexer(110) receives external data signals and the test pattern signals, and outputs one signal selected therefrom into a manager buffer(60) of the external connector units. The control unit(10) outputs the control signals, and controls the multiplexer(110) and the connector buffer(140).
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