| 摘要 |
PURPOSE:To save an operator the trouble to control a bidirectional amplifier by providing a selecting part of each peripheral device with a means which issues a signal and operating OR of this signal and setting the bidirectional amplifier to the enable state by the output signal. CONSTITUTION:Selecting parts 40 and 41 of peripheral devices 8 and 9, which select an address of a peripheral device when it is sent through an address bus 3, are provided with means 11 and 12 which issue signals, and OR between these signals is operated by an OR circuit 10, and a bidirectional amplifier 2 is set to the enable state by the output signal of the OR circuit 10. When addresses of peripheral devices 8 and 9 connected to an extension common bus 7 are sent from a processor 1 through the address bus 3, they are selected by selecting parts 40 and 41, and signals are issued by means 11 and 12, and the bidirectional amplifier 2 is automatically set to the enable state, and the processor 1 and peripheral devices 8 and 9 can communicate with each other. Thus, the trouble of address setting is not required.
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