| 摘要 |
PURPOSE:To reduce the number of signal lines to be required for the tranfer of various information from a keyboard device, by outputting sense switch information always to a data line except the time when other information is transmitted. CONSTITUTION:A data processor 3 senses the sense switch information at random timing. When a keyboard switch is not depressed, a controlling circuit 15 in the keyboard device 1 outputs sense switch information 13 always to the data line 20 through a multiplexer 14 and activates a sense strobe line 23. Consequently, up-to-data sense information is set up in a sense information register 33. Thus, the number of signal lines between the keyboard device 1 and the data processor 3 can be reduced, an interface circuit can be simplified and the random sensing of the sense switch information 13 from the data processor 3 can be processed. |
