| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive circuit, capable of directly driving a liquid crystal display with absolute minimum of components, without enlarging an mounting area even when a microcomputer, in which a liquid crystal display controller is not incorporated is used in this circuit. SOLUTION: In this drive circuit, the main point is to combine common signals for driving liquid crystal by timing outputs of a controller and the voltage division with resistors. This driving circuit is constituted of a microcontroller, a liquid crystal unit and pairs of voltage-dividing resistors which are interposed between the microcontroller and the liquid crystal unit. The port outputs of the mirocontroller output rectangular waves, whose phases each differs byπ/4 (90 deg.), by being controlled by the internal program of the controller. Then, respective liquid crystal segments of a liquid crystal display are driven by the combination of common port outputs, which are to be obtained by dividing the voltages of rectangular waves each of whose phases differs byπ/4 (90 deg.) with a set of the voltage-dividing resistors and output port outputs of the controller.
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