| 摘要 |
PURPOSE:To reduce the number of input and output terminals of an LSI and internal circuits and to reduce the cost, by using a common electrode signal of the display device consisting of passive elements as an input signal of a keyboard. CONSTITUTION:Common electrode signals of a display device 2 are used as inputs of a keyboard 7. Lighting or non-lighting signals are applied to segment electrodes in accordance with these common electrode signals, and what is called voltage averaging is performed for passive elements to perform multiplex driving. Thus, the number of input and output terminals of an LSI 11 to discharge a periodic signal, and buffers in the LSI are reduced, and the cost of the LSI is reduced, and the complicated periodic signal is accepted as keyboard information with a very simple circuit. |
