| 摘要 |
PURPOSE:To facilitate the extension of a display element by constituting a matrix circuit for display of plural pieces of output ports for segment of a microcomputer, and plural pieces of output terminals of at lest one piece of buffer of an integrated circuit. CONSTITUTION:From plural pieces of output ports S1-S8 for segment of a microcomputer 1, a segment signal of a matrix circuit 15 for display is outputted. Simultaneously, based on a variation of a high level and a low level of a control signal from a output port C for control of the microcomputer 1, an address signal and a data signal are outputted from plural pieces of output ports D1-D4 for data. Subsequently, by a segment signal from the microcomputer 1 and plural digit signals from at least one buffer of an integrated circuit 3, display elements 141-1432 of the matrix circuit 15 for display are brought to a display operation. In such a way, a chip area of the integrated circuit 3 can be made small, and also, the number of its input/output terminals can be decreased, and moreover, the display element of the matrix circuit 15 for display can be easily increased.
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