KR100531011B1 - apparatus capable of removing a chattering signal for a matrix switching circuit and method therefore - Google Patents

Abstract

The chattering removing device of the matrix switching device includes a matrix switching unit in which a plurality of switches are connected in an n × m matrix form, and a control unit connected to the matrix switching unit. After scanning for a while, the corresponding calculation operation is executed again and it is determined whether an interrupt has occurred again. Therefore, the scanning operation is executed for a very short time while executing the calculation operation without a separate delay time for removing the chattering signal among the signals output from the switching unit. Since the operation is performed periodically to minimize scanning time and chatter removal time, real-time control is possible, the response of the operation is improved, and an effect of executing an accurate control operation occurs.

Description

Apparatus capable of removing a chattering signal for a matrix switching circuit and method therefore}

The present invention relates to an n × m matrix switching device, and more particularly, to a matrix switching device that enables to eliminate chattering while scanning a matrix switching signal in real time. .

In general, an electronic camera such as a video camera or a digital sill camera stores recording information using a memory device or a magnetic tape instead of storing information photographed using a film.

Therefore, the captured image can be viewed through an external output device, and the captured image can be easily edited or modified in a desired state.

About 15 to 20 switches are attached to the electronic camera, so that the photographing of the subject can be controlled in a desired state.

However, although a plurality of ports are required to connect with a microcomputer controlling such a plurality of switch operations, the number of ports of the microcomputer is limited.

Multiple switches can be designed with n × m matrix switching circuits to enable efficient switch input using only a small number of ports.

In the prior art for controlling the operation of such a matrix switch circuit,

(1) "row-column type keyboard scanning" of US Pat. No. 4,918,445,

(2) "Key Scan Circuits and Methods for Microcomputer Systems" of US Pat. No. 5,264,845, and

(3) "key scanning apparatus" of US Pat. No. 5,235,331.

However, since (1) eliminates chattering using a delay routine method to remove chattering in the switching signal, it is impossible to realize the control operation of a digital still camera requiring real time control, and (2) a telephone button. Scanning is achieved at very low speed for scanning matrix switching circuits.

In addition, since (3) implements the chattering process in hardware, there is a problem that the processing time becomes long and the hardware size increases.

Therefore, when controlling the matrix switching circuit of a digital still camera using such a conventional technique, it is not suitable for a digital still camera that requires a real time control due to a large time delay, and is about 10 to 20 for removing chattering. It takes time, which causes the problem of reducing the number of frames for image processing of a digital still camera. In addition, when checking whether the strobe device used as a flash device is charged at each set time, a problem occurs in that the deviation of the check time due to a time delay occurs severely.

In addition, when performing chattering removal of the matrix switch circuit using a microcomputer, as shown in FIG. 3A, the microcomputer executes the scanning operation of the switching signal for one period, and then delays the predetermined time and scans the switching signal again. Executing a chat removes the chattering operation.

As a result, the microcomputer does not execute the normal digital still camera's control operation as well as the scanning time and chattering removal time of the switching signal, and thus delays the predetermined time, thereby greatly affecting the real-time control and the responsiveness of the operation. The problem of diminishing arises.

Therefore, the technical problem to be achieved by the present invention is to minimize the scanning time of the n × m matrix switching circuit, and to eliminate the time delay for removing chattering.

In order to solve this problem, the present invention sets an interrupt period for scanning a matrix switching signal and a very short interrupt period for removing a chattering signal, and executes a corresponding operation without a delay time. The matrix switching signal is read to read the correct matrix switching signal from which the chattering signal has been removed.

Preferably, the matrix switching unit is connected to a plurality of switches in the form of n × m matrix;

Connected to the matrix switching unit, it is determined whether an interrupt for checking the operation state of the switching unit has occurred, and if it is determined that the interrupt has occurred, by sequentially outputting a set signal through a plurality of output ports during the set interrupt period Each scanned switch signal is sequentially read through a plurality of input ports, and the state of the plurality of output ports is switched to an initial state to release an interrupt state. When the interrupt state is canceled, the interrupt is restarted while executing the corresponding operation. It includes a control unit for determining whether it has occurred.

If 4 x 4 switches are connected to the matrix switching unit, and the processing time of the control unit is 5 MHz (8 bits), the set interrupt period is preferably about 10 ms.

To solve this problem,

Setting an interrupt period;

Determining whether a set interrupt has occurred;

If an interrupt occurs, sequentially outputting configuration signals through a plurality of output ports for a predetermined period, and sequentially reading signals scanned through each connected input port;

Sequentially converting states of the plurality of output ports to an initial state;

And determining whether an interrupt has occurred while executing the corresponding operation.

Then, a person having ordinary knowledge in the art to which the present invention belongs can easily implement the chattering removing device and method thereof according to an embodiment of the present invention with reference to the accompanying drawings. The most preferred embodiment present will be described in detail.

FIG. 1 shows a connection state between a matrix switch circuit and a microcomputer used in a digital still camera according to an embodiment of the present invention.

2 shows an operation flowchart of the central processing unit of the microcomputer according to the embodiment of the present invention.

As shown in Fig. 1, in the structure according to the embodiment of the present invention, the matrix switching unit 2 is connected to the input ports IN1 to IN4 and the output ports OUT1 to OUT4 of the microcomputer 1, respectively.

The matrix switching unit 2 includes switches SW11 to SW14, SW21 to SW24, SW31 to SW34, and SW41 to SW44 at portions where the input ports IN1 to IN4 and the output ports OUT1 to OUT4 cross each other. The pull-up resistors R1 to R4 are connected between the power supply Vcc and the input ports IN1 to IN4, respectively.

The microcomputer 1 has the following structure.

A central processing unit (CPU) 11, which executes a control operation, is connected to the bus 16 to execute a control operation, and the ROM 12 and the RAM 13 are connected to each other, which is required for the control operation of the central processing unit 11. Program, data, or data generated during control are stored.

The input / output port 14 is connected to the bus 16 to perform input / output operations of data or control signals, and the A / D converter 15 is connected to input / output data of the microcomputer 1. B convert the state of the signal to an available state. In addition, since the timer 17 is connected to the bus 16 to count the necessary time during the control operation, an interrupt signal for removing chattering may be generated.

Operation according to an embodiment of the present invention having such a structure will be described with reference to FIG.

As shown in FIG. 2, when the operation starts, the central processing unit 11 of the microcomputer 1 first sets the initial state of the output ports OUT1 to OUT4 of the 4x4 matrix switching unit 2 to a high level " It is made high (S11) and the interrupt period is set (S12).

During the interruption period, the scanning operation of the matrix switching unit 2 should be executed and chattering should be removed.

However, since the reaction speed of the switches SW11 to SW14, SW21 to SW24, SW31 to SW34, and SW41 to SW44 depends on the switching operation of the user, no matter how early a person switches SW11 to SW14, SW21 to SW24 and SW31 to SW34 However, even if SW41 to SW44 are operated, do not operate dozens of times per second, so the interrupt period can be set to a time enough to remove chattering.

As in the embodiment of the present invention, when there are 16 switches SW11 to SW14, SW21 to SW24, SW31 to SW34, and SW41 to SW44, the processing time of the central processing unit 11 of the microcomputer 1 is 5 MHz (8). Bit), the interrupt period is set to about 10 ms.

When the interrupt period is set in this way, the central processing unit 11 of the microcomputer 1 determines whether the interrupt period has been reached (S13), and if it is not the set interrupt period, performs another control operation for photographing the subject. It executes (S14).

At this time, in order to count the interrupt period, the central processing unit 11 of the microcomputer 1 uses the timer 17 built in the microcomputer 1 to count the value counted by the timer 17 at the set time. Interrupt period is determined by determining whether it has reached, and when the set value is reached, the count value is cleared and the set value is counted again.

If the counting value of the determined timer 17 is not an interrupt cycle, the central processing unit 11 of the microcomputer 1 checks the state of charge of the strobe device to control the operation of the digital still camera. Controls the behavior of common digital still cameras, including focusing and brightness control.

However, when the set interrupt period is reached, the central processing unit 11 of the microcomputer 1 proceeds to the interrupt routine and switches each of the switches SW11 to SW14, SW21 to SW24, SW31 to SW34, of the 4x4 matrix switching unit 2. The signals of SW41 to SW44 are scanned to determine the operation state of the matrix switching unit 2.

Therefore, the central processing unit 11 of the microcomputer 1 scans signals of the switches SW11 to SW14, SW21 to SW24, SW31 to SW34, and SW41 to SW44 connected to the first output port OUT1. After the state of the first output port OUT1 is changed from the high level "high" as the initial state to the low level "Low", the signals input through the respective input ports IN1 to IN4 are read. Therefore, since the scanning operation of the switches SW11 to SW14 connected to the first output port OUT1 is completed, the microcomputer 1 changes the first output port OUT1 back to a high level "high" state which is an initial state. (S21).

Therefore, the operation state of each SW11 to SW14 connected to the first output port OUT1 is determined.

In this manner, the states of the switches SW21 to SW24, SW31 to SW34, and SW41 to SW44 connected to the respective output ports OUT2 to OUT4 sequentially from the second output port OUT2 to the fourth output port OUT4. Read all of them (S22 to S24).

Therefore, when all the switching signals of the 4x4 matrix switching unit 2 are scanned, the central processing unit 11 of the microcomputer 1 switches each of the switches SW11 to SW14, SW21 to SW24, SW31 to SW34, and SW41 to SW44. The control operation corresponding to the on / off state of the controller is executed or the control operation of the general digital still camera is executed (S14).

Therefore, as shown in FIG. 3B, when the control period of the microcomputer 1 is interrupted while performing other control, the signal of the matrix switching unit 2 is first scanned, and the corresponding switches SW11 to S1 are performed. After determining the states of SW14, SW21 to SW24, SW31 to SW34, and SW41 to SW44, the control operation corresponding to the operating state can be executed, and then other general control signals are processed again.

Then, the interrupt cycle is again performed to determine the switch state of the matrix switching unit 2.

Therefore, when the switch signal of the matrix switching unit 2 is primarily scanned, when the state of the switched on switch is determined to be off by chattering, the scanning of the secondary matrix switching unit 2 is performed again. In this case, since the amplitude of the chattering signal is very small, it is determined that the switch state is normally turned on.

Therefore, the corresponding control operation is executed in the normal on state without being affected by the chattering signal.

In general, since the interrupt period is much shorter than the time when the user turns on and off one switch and the width of the chattering signal is very short, the chattering signal disappears during the interrupt cycle repeatedly, so that the normal switch signal Will be read.

As described above, since the chattering signal is removed by scanning the switching signal of the matrix switching unit 2 only during an interrupt period of about 10 ms, the central processing unit of the microcomputer 1 for scanning the switching signal. The scanning time and chatter removal time of (11) can be minimized.

Therefore, the effect of the present invention operating in this way is to perform the scanning operation for a very short time while executing the operation operation without a separate delay time for removing the chattering signal of the signal output from the switching unit to scan time and chatter By minimizing the ring removal time, real-time control is possible, the response of the operation is improved, and accurate control operation is executed.

1 is a block diagram of a matrix switch circuit according to an embodiment of the present invention;

2 is an operation flowchart of a central processing unit of a microcomputer according to an embodiment of the present invention,

3A is an operation timing diagram of a microcomputer for removing conventional chattering,

3B is an operation timing diagram of a microcomputer according to an embodiment of the present invention.

Claims (3)

A matrix switching unit in which a plurality of switches are connected in an n × m matrix form; Connected to the matrix switching unit, it is determined whether an interrupt for checking the operation state of the switching unit has occurred, and if it is determined that the interrupt has occurred, by sequentially outputting a set signal through a plurality of output ports during the set interrupt period Each scanned switch signal is sequentially read through a plurality of input ports, and the state of the plurality of output ports is switched to an initial state to release an interrupt state. When the interrupt state is canceled, the interrupt is restarted while executing the corresponding operation. A chattering removal device of the matrix switching device, comprising a control unit for determining whether or not it has occurred. The method of claim 1, wherein the set interrupt period, And 4x4 switches connected to the matrix switching unit, and the processing time of the control unit is 5 MHz (8 bits). Setting an interrupt period; Determining whether a set interrupt has occurred; If an interrupt occurs, sequentially outputting configuration signals through a plurality of output ports for a predetermined period, and sequentially reading signals scanned through each connected input port; Sequentially converting states of the plurality of output ports to an initial state; And determining whether an interrupt has occurred again while executing a corresponding operation operation.