JP3756340B2 - Key switch position signal generation circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a key switch position signal generating circuit for detecting a mode position of a key switch for setting a business mode in an electronic register or a POS system used in a store such as a distribution business.
[0002]
[Prior art]
In the past, key switches have been used for switching operations such as registration, inspection, settlement, and maintenance using electronic registers and POS. By inserting the key into the keyhole of the key switch and rotating the key, a desired job mode is selected and the job can be executed. By limiting the rotation operation range with a key, it is possible to limit the work that can be executed. By having keys with different rotation ranges between the cashier and the manager, it is possible to operate with a limited work range.
[0003]
The key switch utilized in this way has a structure in which the contact between the common terminal and the terminal at each rotational position is closed, and the operation mode can be selected by detecting this closed contact position. At this time, the ON contact of the key switch is converted into a digital signal by the encoder, and this digital signal is directly read by the CPU to know the position of the key switch.
[0004]
FIG. 5 shows a conventional closed contact position detection circuit, in which each contact for each operation mode of the key switch 7 is made to correspond to the 0 and 1 bit signals by the contact position decode circuit 1 and further from this signal to the closed contact position. The encoded signal is generated by the contact position encoding circuit 2, and is read by the CPU via the reading gate circuit 11, thereby detecting which business mode the key switch is in.
[0005]
In most cases, the key switch is arranged near the board surface of the keyboard. Since the key switch is arranged away from the CPU that detects the closed contact position, the signal is routed using a cable and read by the CPU. Also, it is necessary to read the key input signal of the keyboard by the CPU, and the key input signal and the key switch signal are read by being routed by the cable as separate signals.
[0006]
[Problems to be solved by the invention]
In recent years, there have been many cases where a POS system is configured by using personal computer hardware, OS, and BIOS. When using the hardware of a personal computer, it cannot be detected by a conventional method unless a key switch I / O port capable of processing a bit-corresponding signal for each key switch business mode is added. In this case, in order to detect the mode position of the key switch, it is necessary to attach an additional board to the motherboard and route the cable.
[0007]
Therefore, an object of the present invention is to eliminate the need for the key switch bit I / O port and the key switch cable when the POS system is configured using the hardware of the personal computer, the OS, and the BIOS, and to close the key switch. It is an object to provide a key switch position signal generation circuit capable of capturing a contact position as key code data from a keyboard interface of a personal computer.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a key switch position signal generating circuit according to claim 1 of the present invention provides a key switch for setting a business mode and a decode signal corresponding to the closed contact position for each business mode of the key switch. Contact position decoding circuit that generates, contact position encoding circuit that generates an encode signal corresponding to the closed contact position from the decode signal, and contact switching pulse signal generation circuit that generates a pulse signal when the encode signal is input and the closed contact is switched A contact position confirmation signal for confirming the closed contact position, a contact position confirmation pulse signal generation circuit for inputting this contact position confirmation signal and generating a pulse signal, a contact switching pulse signal generation circuit, and a contact position confirmation pulse A gate that allows the scan signal for the keyboard to pass only when one of the pulse signals of the signal generation circuit is input Return signal so that only the return signal that is a closed contact with the decode signal of each contact from the path and the contact position decoding circuit is input for the return signal and becomes active while the scan signal is input And a return signal generating circuit for generating
[0009]
The key switch position signal generating circuit configured as described above determines the contact position of the key switch corresponding to the business mode, rotates the key to the business position to be executed, and connects the common terminal and each contact. The contact position decoding circuit is configured such that only the contact connected to the common terminal has the same voltage level as the common terminal, and all other contacts have different voltage levels. In this way, each contact signal of the key switch is input to the contact position decoding circuit, and its output is input to the contact position encoding circuit and the return signal generation circuit.
[0010]
The contact position decode signal is input to the contact position encoding circuit to generate a code signal corresponding to the closed contact position. This signal does not change unless the key is rotated to change the closed contact, but when the key is rotated, the first or second digit of the code signal always changes from logic 0 to logic 1 or from logic 1 to logic 0. . The contact switching pulse signal generation circuit inputs the signal of each digit of the code signal and generates a pulse signal when there is a change.
[0011]
In order to capture the key switch's closed contact position as key code data from the PC keyboard interface, a keyboard scan signal is input and only when the key switch's closed contact position changes, the keyboard's return signal corresponds to the new closed contact. And the gate circuit performs such a function. The scan signal input to the gate circuit passes through the gate circuit only when the closed contact position of the key switch changes and is input to the return signal generation circuit. In the return signal generation circuit, all the decoded key switch contact signals are input for return signals, and only the return signals that are closed contacts are active and output during the input of the scan signal. .
[0012]
Further, when the key switch is not rotated once after the power is turned on or reset, the return signal that is a closed contact is not active, and the closed contact position, that is, the business mode cannot be detected. Therefore, after the power is turned on or reset, the contact position confirmation signal is input to the contact position confirmation pulse signal generation circuit and the pulse signal is input to the gate circuit so that the closed contact position can be detected without rotating the key switch once. To do. Similarly to when the pulse signal of the contact switching pulse signal generation circuit is input to the gate circuit, the keyboard scan signal is passed when the pulse signal of the contact position confirmation pulse signal generation circuit is input. Thereby, it is possible to detect what mode is set without rotating the key switch. This is applicable not only to a personal computer but also to the case where key switch closing contact information is output as a key code from a keyboard interface.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0014]
FIG. 1 is a block diagram of a key switch position signal generating circuit according to an embodiment of the present invention.
[0015]
In FIG. 1, 1 is a contact position decoding circuit, 2 is a contact position encoding circuit, 3 is a contact switching pulse signal generation circuit, 4 is a contact position confirmation pulse signal generation circuit, 5 is a gate circuit, 6 is a return signal generation circuit, 7 Is a key switch, 8 is a contact position confirmation signal, 9 is a keyboard scan signal, and 10 is a keyboard return signal.
[0016]
The contact position decoding circuit 1 generates a decode signal corresponding to the closed contact position of the key switch 7. The contact position encoding circuit 2 generates an encode signal corresponding to the closed contact position of the key switch 7. The contact switching pulse signal generation circuit 3 generates a pulse when the closed contact is switched. The contact position confirmation signal 8 is input to confirm the closed contact position. The contact position confirmation pulse signal generation circuit 4 receives the contact position confirmation signal 8 and generates a pulse. The gate circuit 5 allows the keyboard scan signal 9 to pass through the outputs of the contact switching pulse signal generation circuit 3 and the contact position confirmation pulse signal generation circuit 4 as gate signals. The return signal generation circuit 6 generates a keyboard return signal 10 based on the contact position decode signal and the gate circuit output signal.
[0017]
Next, the operation of the key switch position signal generation circuit will be described. The contact position of the key switch 7 is determined corresponding to the business mode, and the common terminal and each contact are connected by rotating the key to the business position to be executed. The contact position decoding circuit 1 is configured such that only the contact connected to the common terminal has the same voltage level as the common terminal, and all other contacts have different voltage levels. For example, if the common terminal is pulled up to the ground level (0 V) and the other contacts are pulled up to 5 V via a resistor, only the closed contacts connected to the common terminal are 0 V, and the others are all 5 V. In this way, each contact signal of the key switch 7 is input to the contact position decoding circuit 1, and its output is input to the contact position encoding circuit 2 and the return signal generation circuit 6.
[0018]
The encode signal encoded by the contact position encoding circuit 2 is input to the contact switching pulse signal generation circuit 3, and a pulse signal 3a is generated when the contact is switched. That is, the contact position decode signal is input to the contact position encode circuit 2 to generate an encode signal corresponding to the closed contact position. This signal does not change unless the key is rotated to change the closed contact, but when the key is rotated, the first or second digit of the code signal always changes from logic 0 to logic 1 or from logic 1 to logic 0. . The contact switching pulse signal generation circuit 3 inputs a signal of each digit of the code signal, and generates a pulse signal 3a when there is a change.
[0019]
This pulse signal 3a and a contact position confirmation signal 8 for generating a pulse signal even if the contact is not switched are input to the contact position confirmation pulse signal generation circuit 4 and a pulse signal 4a to be generated is input to the gate circuit 5. The scan signal 9 is output via the return signal generation circuit 6 only during the period in which any one of the pulse signals 3a and 4a is input, but only the return signal that is a closed contact is the scan signal 9. Correspondingly active and output.
[0020]
That is, in order to capture the closed contact position of the key switch 7 as key code data from the keyboard interface of the personal computer, a new closed contact is supported only when the keyboard scan signal 9 is input and the closed contact position of the key switch 7 is changed. It is necessary to output a return signal for the keyboard, and the gate circuit 5 performs such a function. The scan signal 9 input to the gate circuit 5 passes through the gate circuit 5 and is input to the return signal generation circuit 6 only when the closed contact position of the key switch 7 changes. All of the decoded contact signals of the key switch 7 are input to the return signal generation circuit 6 as return signals, and only the return signal 10 which is a closed contact is active during the period when the scan signal 9 is input. And output.
[0021]
However, if the key switch 7 is not rotated once after the power is turned on or reset, the return signal that is a closed contact is not active, and the closed contact position, that is, the business mode cannot be detected. Therefore, after the power is turned on or reset, the contact position confirmation signal 8 is input to the contact position confirmation pulse signal generation circuit 4 and the pulse signal 4a is gated so that the closed contact position can be detected without rotating the key switch once. Input to the circuit 5. Similarly to when the pulse signal 3a of the contact switching pulse signal generation circuit 3 is input to the gate circuit 5, when the pulse signal 4a of the contact position confirmation pulse signal generation circuit 4 is input, the scan signal 9 for the keyboard is passed. Let Thereby, it is possible to detect what mode is set without rotating the key switch 7. This is applicable not only to the personal computer but also to the case where the closed contact information of the key switch 7 is output from the keyboard interface as a key code.
[0022]
In this way, the open / close state of each contact of the key switch 7 is converted into a decode signal at a binary voltage level, input to the return signal generation circuit 6 and converted into an encode signal, and the change of the encode signal and the generation of the closed contact position confirmation signal 8 are generated. Since a pulse is sometimes generated, and the open / close state of each contact of the key switch 7 is output as the keyboard return signal 10 using the scan signal 9 validated by this pulse, the open / close state of each contact of the key switch 7 is directly determined by the CPU. The key switch 7 can be easily used in terms of hardware and software without the need for an interface circuit or a cable for reading data.
[0023]
FIG. 2 is a block diagram showing the overall configuration of the embodiment of the present invention. As shown in FIG. 2, the initial position detection means 12, the key position change detection means 13, the key contact detection means 14, the CPU unit 15, and the key data of the key switch 7 are transmitted to the CPU unit 15 by serial communication. And serial communication means 16. 2 and 1, the key contact detection means 14 corresponds to the contact position decode circuit 1 and the return signal generation circuit 6, and the key position change detection means 13 corresponds to the contact position encode circuit 2 and the contact switching pulse signal generation circuit 3. The initial position detection means 12 corresponds to the contact position confirmation pulse signal generation circuit 4 and the gate circuit 5. As a result, the PC-POS can receive and process the key switch position data via the PS / 2 interface in the same manner as the key code of the normal key.
[0024]
FIG. 3 is a diagram showing a system configuration using personal computer hardware, OS, and BIOS in the embodiment of the present invention. In FIG. 3, 17 is a motherboard, 18 is a memory, 19 is an HDD (hard disk drive), 20 is an FDD (floppy disk drive), 21 is a display, 22 is a printer, 23 is a keyboard, 24 is a peripheral device, 25 is a keyboard A key switch board, 26 is an I / O expansion board, and 27 is a cable. The keyboard 23 scan signal, the return signal, the key switch 7 scan signal, and the return signal are processed by the same sub CPU of the keyboard and key switch board 25, and the key code data is transmitted to the main CPU of the motherboard 17 by serial communication.
[0025]
FIG. 4 is a configuration diagram of a conventional POS system shown for comparison with the embodiment of the present invention. The detection circuit shown in FIG. 5 is configured on the I / O expansion board 26 and mounted on the motherboard 17, and the key switch 7 is connected to the I / O expansion board with a cable.
[0026]
【The invention's effect】
According to the key switch position signal generation circuit of the present invention, a contact switching pulse signal generation circuit that generates a pulse signal when an encode signal is input and a closed contact is switched, and a contact position confirmation signal are input to generate a pulse signal. A contact position confirmation pulse signal generation circuit is provided, and the scan signal for the keyboard is allowed to pass only when the pulse signal of either the contact switching pulse signal generation circuit or the contact position confirmation pulse signal generation circuit is input in the gate circuit, In the return signal generation circuit, the decode signal of each contact from the contact position decode circuit is input for the return signal so that only the return signal that is a closed contact is active and output while the scan signal is input. Since the return signal is generated, the operation mode setting can be changed to the keyboard interface of the computer. Ri can be incorporated as a key code data. This eliminates the need for an interface circuit or cable for directly reading the open / closed state of each contact of the key switch with the CPU, and allows the key switch to be operated easily in terms of hardware and software. It ’s big.
[Brief description of the drawings]
FIG. 1 is a block diagram of a key switch position signal generation circuit according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an overall configuration of an embodiment of the present invention.
FIG. 3 is a configuration diagram showing application of the embodiment of the present invention to a POS system;
FIG. 4 is a configuration diagram of a conventional POS system shown for comparison with the embodiment of the present invention.
FIG. 5 is a block diagram of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Contact position decoding circuit 2 Contact position encoding circuit 3 Contact switching pulse signal generation circuit 3a Pulse signal 4 Contact position confirmation pulse signal generation circuit 4a Pulse signal 5 Gate circuit 6 Return signal generation circuit 7 Key switch 8 Contact position confirmation signal 9 Scan signal 10 Return signal 11 Encoding signal reading gate circuit 17 Motherboard 18 Memory 19 HDD (Hard disk drive)
20 FDD (floppy disk drive)
21 Display 22 Printer 23 Keyboard 24 Peripheral Device 25 Keyboard / Key Switch Board 26 I / O Expansion Board 27 Cable

Claims (1)

A key switch for setting a business mode, a contact position decoding circuit for generating a decode signal corresponding to the closed contact position for each business mode of the key switch, and an encode signal corresponding to the closed contact position from the decode signal A contact position encoding circuit; a contact switching pulse signal generating circuit for generating a pulse signal when the encode signal is input and switching the closed contact; a contact position confirmation signal for confirming the closed contact position; and the contact position confirmation For the keyboard only when the pulse signal of the contact position confirmation pulse signal generation circuit that inputs a signal and generates a pulse signal, or any one of the contact switching pulse signal generation circuit and the contact position confirmation pulse signal generation circuit is input A gate circuit that passes the scan signal of the signal and the decode signal of each contact from the contact position decode circuit. A key switch comprising a return signal generating circuit for generating a return signal so that only a return signal that is input for a return signal and is a closed contact is activated and output while the scan signal is input Position signal generation circuit.

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