Circuit and method for scanning keyboard and electronic equipment

一种键盘扫描、电路的技术，应用在类键盘设备编码、电气元件、电数字数据处理等方向，能够解决键盘扫描电路占用过多、增加键盘成本等问题

Inactive Publication Date: 2011-05-25
HONG FU JIN PRECISION IND (SHENZHEN) CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the increase of buttons often leads to the increase of I / O ports used for keyboard scanning, for example, there are N*M buttons, N+M I / O ports are needed, so that the keyboard scanning circuit takes too much I / O. O port resources, thereby increasing the cost of the keyboard

Method used

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  • Circuit and method for scanning keyboard and electronic equipment
  • Circuit and method for scanning keyboard and electronic equipment
  • Circuit and method for scanning keyboard and electronic equipment

Examples

Experimental program
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Embodiment Construction

[0023] see figure 1 , which is a circuit diagram of a keyboard scanning circuit 200 in a preferred embodiment. The keyboard scanning circuit 200 can utilize a controller 10, such as N input ports K of a single-chip microcomputer 1 ~K n , M-2 output ports W2~W(m-1) to N*M keys S 1-1 ~S n-m Scan for identification.

[0024] The keyboard scanning circuit 200 includes N row lines L1-Ln, M column lines P1-Pm, and M-2 diodes D 2 ~D m-1 , M-2 first resistors R2-R(m-1) and one second resistor Rs, wherein N is a natural number, and M is a natural number greater than or equal to 3. M column lines and N row lines are arranged alternately to form N*M intersections. The N*M intersection points correspond to the N*M buttons S 1-1 ~S n-m . N*M buttons S 1-1 ~S n-m One end of each is electrically connected to the corresponding row line, and the other end is electrically connected to the corresponding column line. In this embodiment, N I / O input ports K1-Kn and M-2 output ports W2...

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PUM

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Abstract

The invention provides a circuit for scanning a keyboard. The circuit comprises N-numbered input ports, N*M-numbered keys, N-numbered row lines, M-numbered column lines, M-2-numbered output ports, M-2-numbered diodes, M-2-numbered first resistors, a second resistor and a voltage source, wherein N is a natural number; M is a natural number not less than 3; the row lines are respectively connected with the N-numbered input ports electrically; one end of the column lines is connected with the N-numbered row lines via N-numbered keys; the other end of the first column line is earthed; the M column line is simultaneously connected with cathodes of the M-2-numbered diodes electrically and the other end of the M column line is earthed via the second resistor; and the rest M-2-numbered column lines are simultaneously connected with the cathodes of the M-2-numbered diodes electrically and are electrically connected with the voltage source via the first resistors, and the other end of the M-2-numbered column lines is electrically connected with the output ports. The invention also provides a method for scanning the keyboard and electronic equipment comprising the circuit.

Description

technical field [0001] The invention relates to an electronic device, in particular to a keyboard scanning circuit and method. Background technique [0002] The keyboard is the main human-machine dialogue input device in electronic products such as computers, PDAs (Personal Digital Assistants), and mobile phones. The keyboard scans the keys on the keyboard through the internal matrix scanning circuit to determine the position of the keys. Most of the existing matrix keyboard scanning circuits use single-chip I / O ports to scan the keyboard. With the increase of functions of electronic products, to complete complex and diverse control functions, the keyboard needs to provide enough keys. Because the increase of buttons often leads to the increase of I / O ports used for keyboard scanning, for example, there are N*M buttons, N+M I / O ports are needed, so that the keyboard scanning circuit takes too much I / O. O port resources, thereby increasing the cost of the keyboard. Conte...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M11/00H03M11/20G06F3/023
CPCH03M11/20G06F3/0202
Inventor 黄仁文张军丁林坤庄宗仁
Owner HONG FU JIN PRECISION IND (SHENZHEN) CO LTD
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