Keyboard signal processing method and keyboard signal circuit

A keyboard signal and processing method technology, applied in the field of control, can solve problems such as poor manufacturability, complex keyboard interface circuit, etc., and achieve the effects of low cost, simple circuit, and simple measurement frequency

Inactive Publication Date: 2003-02-26
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its keyboard interface circuit is more complex, and requires high-precision resistors and their varieties, and the workmanship is too poor.

Method used

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  • Keyboard signal processing method and keyboard signal circuit
  • Keyboard signal processing method and keyboard signal circuit
  • Keyboard signal processing method and keyboard signal circuit

Examples

Experimental program
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Embodiment Construction

[0024] Below in conjunction with accompanying drawing, the implementation of the present invention is described in detail as follows:

[0025] exist figure 1 In the keyboard signal circuit of the keyboard signal processing method, the input terminals of the key switch of the keyboard are respectively provided with several resistors R, and the resistors R are connected in series with each other; the output terminals of the key switch of the keyboard are connected in parallel.

[0026] Among them, R K1 , R K2 ...R KN in series. When the key number switch is not pressed (closed), the circuit is equivalent to an open circuit (the resistance value is infinite). When K 1 When pressed (closed), the circuit resistance is equal to NR. When K 2 When pressed (closed), the circuit resistance is equal to (N-1)R. ..., when K N When pressed (closed), the resistance is equal to R. All resistors R in this circuit take the same resistance value.

[0027] exist figure 2 In the keybo...

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PUM

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Abstract

The keyboard signal processing method includes the following steps: connecting the output of the keyboard signal circuit comprising resistors of different resistance to the input of oscillator or frequency divider; and depressing the key number switches for the oscillator or the frequency divider to output corresponding periodic signal. The present invention features that key assignment coding with signal period realized with serially connected resistors of the same resistance; key assignment coding realized with frequency divier and key number switches for selecting signal output of different period; low cost only one fifth of available keyboard interface IC and simple pulse width measurement and programming with microprocessor; and only one I/O port line for multiple-place key input.

Description

technical field [0001] The invention belongs to the category of control technology, in particular to the control technology of keyboard signals of instruments and electrical equipment. Background technique [0002] The keyboard is an indispensable man-machine dialogue device in instrumentation, electrical equipment and measurement and control systems. Traditional key input recognition methods include direct type: each key occupies one I / O port line; matrix scanning type: M×N bit keys occupy M+N I / O port lines; or use a special keyboard coding control chip , such as the classic chip 8279, and the BC7280 that has appeared in recent years. According to the special keyboard coding, the interface mode between the control chip and the single-chip microcomputer can be divided into two types; one is the parallel port mode, and the other is the serial port mode. Regardless of the interface method, the keyboard coding control chip will occupy more tha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F3/00
Inventor 李刚林凌任惠茹
Owner TIANJIN UNIV
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