KR890005310B1 - Key scan circuit - Google Patents

Abstract

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Description

Kisken and Sensing Circuits

1 is a conventional circuit diagram.

2 is a circuit diagram according to the present invention.

3 is a specific embodiment of the 8-port Kisken circuit.

* Explanation of symbols for main parts of the drawings

CPU: Microprocessor KBD: Keyboard

Y ₁ -Y _n : port

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key scan circuit of a keyboard, which is an input device of a microcomputer, and more particularly to a kisken circuit capable of performing kisscan and key sensing through the same port. Read circuit, especially when a large amount of position data is shown in Fig. 1 of the conventional keyboard Kisken circuit diagram, the microprocessor (CPU) through the first port (Port1) key scan data (key scan) data), the demultiplexer (DMUX) demultiplexes the scan data inputted through the input terminals I1 to I4 to output an arbitrary output line for the corresponding Kiken data among the output terminals XO-X15. Enable only At this time, the keys of the keyboard are connected to the output terminal of the demultiplexer (DMUX), and the key information according to the pressing of the corresponding key is connected, and the information corresponding to the pressing of the key is connected to the second port of the microprocessor (CPU). It is sensed through port2.

Therefore, when a key connected to the enabled line of the demultiplexer DMUX is pressed, the microprocessor (CPU) senses the corresponding key information through the second port (Port2).

However, the Kisken circuit as described above outputs Kisken data through the first port, demultiplexes it, and detects the generation of key information through the second port. Sensing ports were used differently, and since keyboard PCB (Print Circuit Board) realization occupies a large area, there was a problem in realizing light weight, short weight, and low price.

Accordingly, an object of the present invention is to provide a kissken circuit capable of performing kisscans and key sensing with respective ports by connecting ports of a microprocessor to a keyboard.

In order to accomplish the above object, the present invention provides a microprocessor that connects the first-nth ports with a keyboard to output kisken data and senses pressed keys, and connects one side contact of the first group key to the first column line. And connect one side contact of the n-1th group key to the nth-1th line in the order of connecting the one side contact of the second group key to the second row line; One n-th group key is configured in the order that the other contact point of the first group key is connected to the second-n-th row line, and the other contact point of the second group key is connected to the third-n-th row line. ; A keyboard configured to form a first-column line as the first port and an n-th row line as the nth port, so that the Kisken data from any microprocessor to any one of the first-first n-1 ports And outputs key information to a port to which a key of a corresponding group is pressed among the second-nth ports.

2 is a Kisken circuit diagram according to the present invention. N-1 in order to connect one side contact of the first group key G1 to the first column line C1, and one side contact of the second group key G2 to the second column line C2. One side contact of the group key Gn-1 is connected to an n-1th column line Cn-1; The other contact of the first group key G1 is connected to the second-second n-1 row line R2-R _n-1 , and the other contact of the second group key G2 is connected to the third-third n-1. The n-th group key Gn-1 is constituted by one in the order of connection to the row line R3-R _n-1 ; A first column line C1 is formed through the first port Y1, a first row line R1 and a second column line C2 are formed through the second port Y2, and the third port Y3 is formed. In order to form the second row line (R2) and the third column line (C3) to the n-th row (Yn) in order to form the n-th row line (Rn-1), the keyboard is provided with a micro When the processor outputs Kisken data to any one of the first-th n-th ports (Y1-Yn-1), the port of the corresponding group of the second-nth ports (Y2-Yn) is pressed. And to sense key information.

FIG. 3 is a diagram specifically illustrating an example of scanning and sensing each key of the keyboard KBD using eight ports of a microprocessor (CPU).

Referring to the present invention in detail based on the above-described configuration, first, the microprocessor (CPU) outputs Kisken data through the ports (Y1-Yn), while outputting a "low" signal to the first port (Y1) while remaining Outputs a "high" signal to ports Y2-Yn.

Then, a "low" signal is applied to the first column line C1 of the keyboard KBD, and a "high" signal is applied to the column lines C2-Cn-1. At this time, since one side of the first group key G1 is connected to the first column line C1, if any key of the first group key G1 is pressed, the corresponding port and the first column line C1 are pressed. Is connected. Accordingly, since the microprocessor (CPU) receives a "low" signal to the port to which the corresponding key is connected, the microprocessor (CPU) recognizes that the corresponding key is pressed and processes the system according to the corresponding key data. At this time, even if the remaining group keys G1 -Gn-1 are pressed, the microprocessor CPU does not recognize this. Thereafter, the microprocessor (CPU) outputs a "low" signal to the second port Y2, and generates a "high" signal to the remaining ports Y1 and Y3-Yn, thereby causing the second group key. If any key in (G2) is pressed, it is recognized by the port to which the key is connected.

In this order, the microprocessor (CPU) outputs a sequential "low" state Kisken signal by one of the ports (Y1-Yn) in one scan period of the keyboard KBD, while the other keys are pressed. Outputs a "high" signal for sensing. At this time, the microprocessor (CPU) ignores key information sensed through a port lower than a port for outputting a kisscan signal during a key sensing process, in which one key senses twice in one scan period of the keyboard KBD. This is to prevent it.

A process of simultaneously performing kisscan and sensing with one port as described above will be described in detail with reference to FIG. 3. In FIG. 3, eight ports Y1 to Y8 are connected to the keyboard KBD, and the keyboard KBD includes a total of 28 keys from the first group key G1 to the seventh group key G7.

First, when the "low" signal for the kisscan is output to the first port Y1, the signal is applied to one end of the first group key G1, and the microprocessor CPU is connected to the remaining ports Y2-Y8. Outputs a "high" signal. At this time, the microprocessor (CPU) stores the state of the port (Y2-Y8) in an internal register, if any key of the first group key is pressed, the state of the key is applied as "low", so that the microprocessor ( CPU) can see which key was pressed.

Thereafter, the microprocessor CPU outputs a "low" signal to the second port Y2 and outputs a "high" signal to the remaining ports Y1 and Y3-Y8.

Then, a "low" signal is applied to one end of the second group key G2 and a "high" signal is applied to the other end, so that the second group key G2 can be recognized. At this time, a key K11 is connected to the second port Y2 in the second group G1. At this time, when the key K11 is pressed, the Y1 is “low” and the key sensing is performed. Cause. Therefore, in order to process this, the microprocessor (CPU) ignores the key information sensed by the ports that output the scan signal before the current scan port. That is, when outputting the kisscan signal to the second port Y2, the microprocessor CPU ignores key information sensed by the first port Y1 and senses the second to eighth ports Y3-Y8. Only key information of the second font G1 is processed.

That is, for example, when the kisscan signal is output to the fifth port Y5, the key of the first-fourth group G1-G4 that can be sensed through the first-fourth port Y1-Y4 ( It ignores the information of K14, K23, K32, and K41, and processes only the information of the keys K51-K53 of the fifth group G5 that can be sensed through the sixth-eighth ports Y6-Y8.

Accordingly, the microprocessor (CPU) outputs a sequential " low " state kisscan signal from the first port Y1 to the seventh port Y7 at regular intervals, and at this time, key sensing to the remaining ports other than the kisscan port. Outputs a "high" signal for. Therefore, the first port Y1 is a dedicated port for kisscans, the eighth port Y8 is a dedicated port for key sensing, and the remaining ports Y2-Y7 are ports for simultaneously performing kisscans and sensing.

When kissingcans and senses the keyboard KBD in the above-described manner, an operation as shown in Table 1 below is performed.

When the keyboard KBD is configured in the above manner, when n ports of the microprocessor CPU are detected, Σ ⁿ (n-1) [that is, (n-1) keys can be detected. p is a port), so using two-byte ports (Y1-Y16) can detect 120 keys, which can be done with a typical one chip micoroprocessor.

As described above, since one can carry out kisscan and sensing at the same time, there is an advantage that the circuit can be simplified and the PCB area can be reduced, thereby miniaturizing.

Claims (1)

In a kisscan circuit having a microprocessor (CPU) for scanning and sensing a keyboard by connecting n ports of the keyboard, one side contact of the first group key G1 is connected to the first column line C1, and the second One-side contact of the n-th group key Gn-1 is connected to the n-th column line Cn-1 in the order of connecting one contact point of the group key G2 to the second column line C2. ; The other contact of the first group key G1 is connected to the second-second n-1 row line R2-R _n-1 , and the other contact of the second group key G2 is connected to the third-third n-1. The n-th group key Gn-1 is constituted by one in the order of connection to the row line R3-R _n-1 ; A first column line C1 is formed through the first port Y1, a first row line R1 and a second column line C2 are formed through the second port Y2, and the third port Y3 is formed. Keyboard KBD configured to form the n-th row line Rn-1 through the n-th port Yn in the order of forming the second row line R2 and the third column line C3). And outputting Kisken data to any one of the first-th n-th ports (Y1-Yn-1) by the microprocessor, the corresponding group of the second-nth ports (Y2-Yn) Keyscan and sensing circuitry, characterized in that it is operated to sense the key information to the port is pressed.

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