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Method for scanning keyboard

A keyboard scanning and keyboard technology, applied in the field of keyboard scanning, can solve the problem of insufficient pins, etc., and achieve the effect of saving pins, simple and clear algorithm, and fast speed

Inactive Publication Date: 2012-11-14
SHANGHAI SIMCOM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a keyboard scanning method in order to overcome the defect of insufficient pins in the prior art, and the keyboard scanning method supports more pins through an extended chip

Method used

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  • Method for scanning keyboard
  • Method for scanning keyboard

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Embodiment Construction

[0024] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to describe the technical solution of the present invention in detail. Such as figure 1 As shown, the keyboard using the keyboard scanning method in the present invention includes a matrix composed of a plurality of row signal pins KBR1-KBR5 and a plurality of column signal pins KBC1-KBC5, and each row signal pin and column signal pin correspond to two switches of a switch. For example, the signal pin KBR1 in the first row and the signal pin KBC1 in the first column respectively correspond to the two ends of the switch SW11 in the first row and the first column. When the switch SW11 is opened (when the corresponding button is pressed), the switch SW11 will The first row signal pin KBR1 and the first column signal pin KBC1 are conductively connected. Such as figure 2 As shown, a main chip MSM6280 and an expansion chip PCA9555 pass I 2 C bus connection, the...

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PUM

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Abstract

The invention discloses a method for scanning a keyboard, which comprises the following steps: S1, initializing an extension chip; S2, registering an interrupt handler to an interrupt pin; S3, pressing keys on the keyboard; S4, reading out column signal pins having low levels and determining the column numbers of keys; S5, reconfiguring the input-output terminals and level signals of line signal pins and the column signal pins; S6, reading out the line signal pins having low levels and determining the line numbers of the keys; S7, restoring the initialization configuration of the extension chip, returning to the step S3, and waiting for the next time of key pressing; and S8, according to the determined column numbers and the line numbers, determining specific key codes and sending the codes to an application layer to perform corresponding treatments. The method for scanning the keyboard extends more pins, and the scanning process is comparatively simple.

Description

technical field [0001] The invention relates to a keyboard scanning method, in particular to a keyboard scanning method realized by using an expansion chip. Background technique [0002] The current keyboard scanning algorithm adopts the row-column matrix method, so 5*5 keyboard needs 10 pins, sometimes the number of pins is not enough in actual development, so it needs to be extended to support more pins. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a keyboard scanning method in order to overcome the defect of insufficient pins in the prior art. The keyboard scanning method supports more pins through an extended chip. [0004] The present invention solves the above-mentioned technical problems through the following technical solutions: a keyboard scanning method, a keyboard includes a matrix composed of a plurality of row signal pins and a plurality of column signal pins, each row signal pin and each column s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M11/20
Inventor 吴斌
Owner SHANGHAI SIMCOM LTD
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