JPS58176737A - Keyboard test device - Google Patents

Abstract

PURPOSE:To increase the efficiency of a key test, by supplying the coding signals of all keys stored in a storing circuit to a keyboard via a pseudo switch circuit and then comparing the output decoding signal with the output of a decoder within the keyboard. CONSTITUTION:Code data is set to a pseudo switch circuit 13 from a storing circuit 12 storing the code data of all keys of a key switch 2a of a keyboard 1a under the control of a control circuit 11 of a keyboard test device 10. The circuit 13 gives the code data to a Y receiver 4 via a connector 7 of the keyboard 1a as well as to an encoder EC14. The output of the receiver 4 is fed to an EC6 to be encoded, and the encoded signal of the EC6 is compared with the signal encoded by the EC14 through a comparator 15. Then an alarm 17 is delivered via the circuit 11 when no coincidence is obtained, and at the same time a key switch of discordance is displayed 19. While the voltage of an X driver 3 obtained when a key is pushed is compared 20 with the reference voltage given from a reference voltage generating circuit 21. When the voltage of the driver 3 is higher than the reference voltage, the contact resistance value of the switch is increased to give an alarm as well as a display.

Description

Detailed Description of the Invention (1) Technical Field of the Invention The present invention relates to a keyboard tester for checking the operation of each switch in a switch matrix used in a keyboard and the operation of various functional circuits connected to the switches. It is.

(2) Background of the Technology In general, a keyboard is used as an operation input means for an information processing apparatus, particularly for inputting data such as codes, numbers, functions, and the like. In addition to inputting single data, this keyboard is used to input other significant information such as name, product name, etc. by pressing the same key switch. Particularly when inputting kanji data, the number of key switches installed is increasing in proportion to the types of characters handled. Regarding key switches, there are various types such as those made of conductive rubber and aimed at being thin, those using reed switches to make them cheaper, and those using Hall elements for the purpose of improving reliability. The structure with the mechanical switch was common to all these keyboards, and was the most important inspection point compared to other circuit parts. In addition, the receiver circuit, which receives electrical signals from the key switch, the encoder circuit, and the driver circuit, which supplies electrical signals, were the next most important parts to be tested.

(3) Problems with the conventional technology Please refer to Figure 1 regarding the conventional keyboard test. I will explain from J. Keyboard 1 has keys as shown in the diagram.
Switch matrix 2a, Xi consisting of switches 2
' Driver 3, Y receiver 4, pull-up resistor group 5,
Encoder 6 having an interface section with an external circuit
The main structure is the key pressed by the author.
The code data generated based on the open/close signal from the switch 2 is encoded by the encoder 6 in accordance with information defined by the key top of the key switch 2, etc., and sent to an external device. . When testing the keyboard 1, a tester 10 is connected as the external device. In the test 1110 in which code data is stored in advance in the order of arrangement of the key switches 2, each time the operator sends code data from the keyboard 1 in the order of arrangement, the code data in the tester and the code data from the keyboard are combined. Test by making comparisons. However, in such a test, it is not possible to test the operation of the keyboard circuit unless the operator actually operates the key switches accurately while making sure that the order in which the keys and switches are pressed corresponds to the order in which the codes and data stored in the tester are arranged. Further, when the contact resistance of the key switch 2 is several ohms, it can be determined that the key switch 2 is defective, but it is not possible to discover an unstable initial state that is becoming defective. For this reason, it was not possible to save labor in testing, and furthermore, there was a problem with the accuracy of testing and evaluation of key switches.

(4) Purpose of the invention The present invention is intended to solve the above-mentioned conventional problems.
The purpose of this test is to detect defects in the circuit operation within the keyboard and key switches at an early stage, and to be able to perform reliable tests on all key switches without requiring the operator to press keys.

(5) Structure of the invention In the present invention, key switches are arranged in a matrix,
An X driver connected to a terminal defined in the row direction of the key switch, a Y receiver connected to a terminal defined in the column direction of the key switch, and output signals from the X driver and Y receiver, respectively. The keyboard has an encoder into which a code is input, and outputs each unique code and data by operating a key switch, the keyboard having an output signal line of an X driver, an input signal line of a Y receiver, and a circuit external to the keyboard. A code/data storage circuit that stores test food data, a pseudo switch circuit that temporarily stores the code/data sequentially corresponding to key switches, and a an encoder that receives code data from the switch circuit and food data from the connection section of the keyboard; and a first comparison circuit that receives output code data from the encoder and the keyboard interface circuit, respectively. and an alarm and/or display circuit that issues an alarm or display in response to the output of the comparison circuit, reads code data from the code data storage circuit to the pseudo switch circuit, and reads the code data to the keyboard. The code data sent to the connection part of the keyboard and obtained via the contact M part of the keyboard, the encoded output by the code data from the pseudo switch circuit, and the code data from the keyboard interface circuit are compared manually. It has a control circuit that issues alarms and displays based on the comparison results, and allows various circuit tests inside the keyboard to be performed without the need to press any keys. It has a second comparator circuit which takes the voltage level signal as one input and the voltage level from the reference voltage generation circuit provided in the tester as the other input, and responds to the pressing operation of the key switch in sequence. A control circuit inspects the terminal voltage of the key switch 2 according to the output of the second comparator circuit, and issues an alarm and/or alarm to determine whether the key switch is good or not.
or displayed.

(6) Embodiments of the Invention Hereinafter, embodiments of the present invention will be described with reference to FIG. The figure shows the connection between the keyboard tester of the present invention (hereinafter simply referred to as tester) and the keyboard to be tested. Note that the same reference numerals as in FIG. 1 refer to the same items. Further, in the figure, reference numeral 7 denotes an output connector connected to both ends of the key switch 2 by wiring. 8
is a drive/sense line for connecting the output connector 7 to the tester IO.

First, we will explain how the test can be performed under the control of a pseudo-switch circuit inside the tester, which is the same as if all the key switches were pressed by the operator. That is, the keyboard L1a is selected by the built-in X driver selection circuit 9 (the X driver 3 sequentially drives the drive &112b according to instructions from the H4 S. In this way, the selection signal S is always sent to the X driver 3. Therefore, any one of the plurality of drive lines 2b from the X driver 3 is being driven.The drive lines 2b of the X driver 3 are each connected to one end of the key switch 20, and further connected to the output connector 7. It is also connected to the keyboard so that drive signals can be output to the outside of the keyboard.

The drive line 2b connected to the X driver 3 is also
It is also connected to the human power section of the encoder 6, and the drive signal output from the X driver 3 is given to the encoder 6, respectively.

The output connector 7 is separately connected to input signal lines of the Y receiver 4, and a voltage Vcc is applied to each of the input signal lines from the outside via a pull amplifier resistor group 5.

Further, codes and data are input to this Y receiver 6 from the X drive 3 and Y receiver 4, respectively, and the codes and data of the X driver 3 are sent to the tester 10 through the output connector 7 and the drive/sense line 8. The code data is sent out as encoded code data. FIG. 3 shows the details of automatically testing the circuit built into the keyboard by decoding the code signal sent from the keyboard 1a.

To explain the figure, the control circuit 11 instructs the Wi-like switch circuit 13 to sequentially read out code/data to be set from a predetermined location in the pattern storage circuit. When the predetermined data (CEF) is completed in the pseudo switch circuit 13, the pseudo switch circuit 11a13 is sent to the encoder 14 in the tester 10.
Input the code and data of Y to the output connector 8 of keyboard la via drive/sense line 8.
Code data is provided to receiver 4. On the other hand,
Since the encoder 14 is given the drive signal of the X driver 3 from the output code 1' data 8 of the keyboard la, the code data output from the encoder 14 in the test B10 are the codes and data related to the matrices X and Y, respectively. This is the encoded output of the data. Also, exam! ! 1
The code data from the encoder 6 in the keyhole 1' that can be obtained by the code data from the pattern storage circuit 12 sent from the Y receiver 4 and the code data generated inside the keyboard 1a. The data is compared with the output from the encoder 14 produced by the tester 10 in the comparison circuit 15 according to a command from the control circuit 11, and the comparison output is given to the control circuit 11. When the circuit inside the keyboard la operates normally, the comparison circuit 1
5 outputs a coincidence output to the control circuit 11, and also outputs a mismatch output to the control circuit 11 when there is an abnormality such as a failure. The above comparison operation is performed by applying the strobe signal from the control circuit 11 to the comparison circuit 15 in a matching state in which the output code data from the encoders 14 are to be compared.
It is done in synchronization with the pulse. Further, if the comparison result is a mismatch as a result of this comparison operation, the comparison circuit 15 receives the mismatch signal and sends an alarm signal a to the alarm circuit 16. Then, when the alarm circuit 16 receives the alarm signal a, the alarm circuit 16
A signal is given to drive the key switch 7, thereby causing an alarm 17 to sound and informing the operator that there is a defect in the key switch 2. At the same time as sending the signal to the alarm circuit 16, the control circuit 11 generates a signal to switch the display circuit 18 to a state in which it can receive the code data from the encoder 14, and displays food data on the display 19. It is something. Then, the operator can identify which circuit part of the keyboard la has the abnormality based on the information shown on the display 19. In this manner, the control circuit 11 sequentially reads out the information necessary to test the keyboard la from the pattern storage circuit 12, and sends this information to the keyboard la via the pseudo switch circuit 13. The tester 10 receives raw code data from the key switch in the keyboard la, and inputs it into the encoder 14 inside the tester 10 to obtain an encoded output signal and the raw code sent out from the tester 10. The code data is input data to one encoder ■4, and the code data obtained from key switch 2 of keyboard la is input data to the other encoder, and the code data output from the encoder inside the keyboard. By sequentially comparing the circuits, a test is automatically performed to confirm the operation of the circuit in response to the operation of all keys and switches.

Next, the function confirmation of the key switch 20 of the keyboard 1a will be explained with reference to FIGS. 3 and 4. The function of the key switch 20 is determined mainly by the value of contact resistance when the contacts of the key switch are closed. If the contact resistance is several ohms, it can be immediately determined to be defective, but if it is about 100 ohms, it is determined to be good. In other words, the open/close state of the key switch is detected by detecting the voltage level applied to both ends of the key switch, but normally in the case of a contact resistance of about 100Ω, the open/close state of the key switch 2 is detected. The voltage level is lower than the voltage level for detecting the state, so the key switch 2 is treated as a good product without being able to distinguish it from an open state when it is defective. In order to maintain stable quality in the key switch 2, it is essential that the contact resistance is several Ω or less.
Products of around 100 Ω work normally immediately after inspection, but it has been found that they tend to rapidly increase resistance during subsequent use, so these must be extracted during inspection and replaced with non-defective products.C) . In such a case, the comparison reference voltage level of the detection circuit that detects the open/closed state of key switch 2 should be set to a lower value than when in use, that is, it should be detected as a good product only when the contact resistance is several Ω or less. This makes it clear to distinguish between defective products and non-defective products, and ensures stable operation of the keyboard 1a. For this purpose, as shown in FIG. 3, various signals on the input line of the Y receiver are input to the tester 10 via the output connector 7, and to the second comparator circuit 20 via the drive/sense line 8. 2 comparison circuit 2
The voltage level signal from the other reference voltage generating circuit 21 that is input to 0 is applied at a voltage level lower than the input terminal level of the Y receiver 4 in the keyboard. And the control circuit 11
When the drive signal is sequentially applied from the XV Lie equation 3, it is compared with the input line signal of the Y receiver 4 associated with the X driver 3, and the low level voltage level signal is input to the second comparison circuit 20. In addition, the control circuit 11 confirms that a low-level voltage input signal is applied and detects that the control circuit 11 is operating normally. On the contrary, when the second comparison circuit 20 determines that there is a high level voltage input and generates an output signal, it outputs to the control circuit 11 that the key switch 2 is defective, and the control circuit 11 The location of the defective key switch 2 is displayed on the display 19 through the alarm circuit 16. FIG. 4 shows the reference level signal for detecting the input signal of the Y receiver 40 with respect to the level signal of the input line of the Y receiver 4, and the reference level signal at the time of testing the key matrix switch 1a. The input detection level of the Y register 4 is lower than the reference voltage when the key matrix switch is tested when the key switch is suppressed, indicating that it is a good product. On the other hand, if the price is high, it is a defective product.

As explained above, the present invention includes a code storage circuit that stores code data that can be given to test all keys on a keyboard, and a pseudo switch that sequentially reads code data from the code storage circuit and sends it to the keyboard. a circuit, an encoder that manually inputs the signal from the pseudo switch circuit and the raw signal from the key switch of the keyboard, a comparator circuit that compares the output of the encoder with the output of the encoder in the keyboard, and the keys of the keyboard. -Equipped with a second comparator circuit that operates at a lower level voltage than the reference voltage that determines whether the switches are open or closed, and a control circuit that controls the operation of each of the above circuits, eliminating the need to press the key I knob. As if all the keys were pressed one after another, a signal is automatically given to check the circuit inside the keyboard, and the key
The contact status of a single switch can also be automatically inspected from the outside.

In this way, we will confirm the normal operation of the circuit inside the keyboard.
It is possible to detect defects in key switches at an early stage, and to perform reliable tests on all key switches without requiring the operator to press keys.

[Brief explanation of the drawing]

FIG. 1 shows a conventional test block diagram showing s--, tr-, .:,'°, 9-board tester and 0 connections. FIG. 2 is a test block diagram showing the connection between the keyboard and the keyboard tester in the present invention. FIG. 3 is a block diagram of the internal circuit of the keyboard tester main body according to the present invention. Figure 4 shows Y during key switch inspection in the present invention.
FIG. 3 is an explanatory diagram showing the relationship between the input detection level to the receiver and the voltage level actually appearing at the terminal of the key switch in the form of a waveform.

Claims (1)

[Claims] (1) Key switches are arranged in a matrix, and each X driver is connected to a terminal defined in the row direction of the key switch, and each is connected to a terminal defined in the column direction of the key switch. Y receiver and X driver and Y
It has an encoder into which each output signal from the receiver is input, and when the key switch is operated, each unique code and
In a keyboard that outputs data, a connection part for connecting each of the output signal lines of the X driver to a circuit outside the keyboard is provided in the keyboard, and a code/data storage circuit that stores test codes/data and the code・
A pseudo-switch circuit that temporarily stores data in correspondence with sequential key switches, and a code/switch circuit from the pseudo-switch circuit.
An encoder that receives code data from the connection section of the data and keyboard, and an output code from each of the encoder and keyboard interface circuits.
It has a first comparator circuit that inputs data manually, and an alarm/display circuit that issues an alarm and/or display in response to the output of the comparator circuit, and the code data is transferred from the hood data storage circuit to the pseudo switch circuit. and sends the code data to the connection part of the keyboard, and encodes the code data from the keyboard through the connection part and the human data from the pseudo switch circuit and the hood from the keyboard interface circuit. - It has a control circuit that inputs a large amount of data for comparison, and issues alarms and displays based on the comparison results, making it possible to test various circuits inside the keyboard without having to press any keys! A keyboard 1' tester characterized by the following. (2. Claim 1 provides that in a memory keyboard Ka-type tester, one input is the voltage level signal of the X driver obtained from the connection part of the keyboard, and a reference voltage generation circuit provided in the tester is provided. A second comparator circuit receives a voltage signal from the second comparator circuit as its other input, and in response to sequential key switch press operations, the control circuit converts the terminal voltage of the key switch to the second comparator circuit. A keyboard tester characterized in that it tests according to the output and warns and/or displays whether the key switch is good or bad.