Electronic musical instrument having mother board communicable with plug- in board

摘要

An electronic musical instrument is constructed on a mother board for editing a parameter of an extension board necessary for generating a music tone while monitoring the parameter according to display information. In the instrument, a display device is provided for displaying a current value of the parameter to be edited. An input device is operable for inputting an operational variable effective to change the current value of the parameter. A first control circuit contained in a CPU of the mother board is operative when receiving the display information for controlling the display device to display the current value of the parameter, and is operative when the operational variable is inputted from the input device for transmitting the operational variable to the extension board. A second control circuit composed of a CPU and a RAM is provided in the extension board for memorizing the current value of the parameter so as to generate the music tone, and is operative when the operational variable is transmitted from the first control circuit for updating the current value of the parameter and for transmitting back the display formation indicative of the updated value of the parameter to the first control circuit so that the first control circuit of the mother board can control the display device to display the updated value of the parameter of the extension board.