JPS61165121A - Keyboard connection detecting system - Google Patents

Abstract

PURPOSE:To detect automatically a connection by a scanning circuit in case a keyboard is connected, by setting it to the same state as a switch connection of one piece of diode. CONSTITUTION:A diode 912 is always placed so as to be connected to a wiring of X and Y axes. As a result, a signal (a) always flows to a scanning circuit of a control part 1a, and it is detected in the same way as if a key is depressed. However, unless a ten key board 5a is connected, this signal (a) is not transmitted to the scanning circuit. Accordingly, in accordance with whether the signal (a) is sent to a CPU or not, whether the ten key board 5a has been connected or not is decided.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an input/output device in which a keyboard is connected to a control unit, and in particular, it is possible for the control unit to detect that the keyboard is connected. This is related to a keyboard connection detection method that can be used.

Recently, banking systems and point of sale management (PO3)
) With the spread of systems, various input devices have been developed and put into practical use, but simple keyboards such as numeric keyboards and password input keyboards are connected to the main bodies of these devices at any time. There is. There is a need for a method that allows the main body of the device to automatically detect when such a simple keyboard is connected.

[Conventional technology]

FIG. 3 shows an example of a human-powered device. The main body 1 of the apparatus is provided with a setting switch 2, and a numeric keyboard 5 is detachably connected to the connecting portion 3 via a connector 4G via a connecting cable 6.

A simple keyboard such as the numeric keypad 5 may be optional in some cases, or may be removed as it is unnecessary depending on the job.

At this time, whether or not the keyboard 5 is connected is determined by manually setting the setting switch 2 of the main body 1 of the apparatus, and notifying a control section (not shown) to run the corresponding program.

[Problem that the invention seeks to solve]

- B According to the conventional method, the connection of the keyboard 5 is manually set using the setting switch 2, which is troublesome. It is also possible to use one signal line of the connection cable 6 and detect it with an automatic crystal, but since a curled wire or the like is usually used, it is necessary to make the cotton as thin as possible, and increase the number of signal wires. It is desirable to avoid this, and there is also the problem that a determination circuit is required.

[Means for solving problems]

The present invention provides conduction means for bringing at least one of the key contacts in a matrix into a connected state, and the control unit determines whether or not the keyboard is connected based on the i4 state of the key contact provided with the conduction means. It is a detection method, and by covering it, the above problems can be solved. .

[Effect]

According to the present invention, instead of the conventional method of manually setting the setting switch, for example, by setting one of the diodes in the same configuration as the strip connection, when the keyboard is connected, the scanning circuit automatically sets the setting switch. connection is detected.

〔Example〕

Embodiments of the invention will be described below with reference to FIGS. 1 and 2 (al and 2). FIG. 1 is a circuit diagram showing an embodiment according to the present invention, and FIG. 2 +a+ and ibl are enlarged views of the parts shown in FIG. Throughout the design, the same symbol is the same pair'
It shows an image.

In FIG. 1, the range indicated by the two-dot chain line is
The control unit 1a and the ten-key keyboard 5a are shown.

The decoder 7 is a central processing unit (hereinafter referred to as CPU), which is not shown in the figure.
The output terminal is selected by the signals S, , S2 inputted from the output terminals, and only the output line becomes low level.

The data selector 8 has a function of selecting which input signal is to be output to the output terminal H based on the signal S3.-34 input from the CPU.

゛ Therefore, the signal 4SI+'S2 input to the decoder 7
and the signal S3. input to the data selector 8. In combination with S, a scanning circuit for selecting an output terminal is constructed.

Further, 9 and 9.2 are diodes, and 10. ~10. ．． indicates a key switch.

Diode9. ~9.2 are arranged in a matrix on the X and Y axes, and diodes 91~91. are arranged in pairs with the key switches 101 to 10□, respectively, and the X and Y axis wirings are connected by actuation of the switches. Further, the Y-axis wiring is connected to +5V via a resistor.

Figure 2 (Diode 9., !: Keith Isochi 10.
．． is shown enlarged.

Further, the diode 91□ is directly connected to the X and Y axis wiring. FIG. 2 (bl shows an enlarged view of the diode at 91°.

With such a configuration and function, for example, key switch 10. ~10. .

When one or more of the buttons are pressed, the CPU can be notified of which one was pressed.

Here, the diode 91□ is always connected to X and Y, so it is equivalent to a key being pressed.

That is, when the keyboard 5a is connected to the main body 1 of the apparatus, the signal a always flows through the scanning circuit of the control section 1a, and it is detected as if a key had been pressed.

However, if the ten-key keyboard 5a is not connected, this signal a is naturally not applied to the scanning circuit.

Therefore, it can be determined whether the ten-key keyboard 5a is connected or not, depending on whether the signal a is sent to the CPU or not.

Since the connection of the ten-key keyboard 5a can be automatically detected in this way, there is no need for manual settings or an increase in extra signal lines.

〔Effect of the invention〕

As explained above, according to the present invention, ■Can automatically detect whether or not a keyboard is connected.

■No manual settings required.

■Easy configuration and no extra signal lines.

There is an effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
Figures tar and (b) are enlarged views of the main parts of Figure 1, and Figure 3 is an explanatory diagram showing the conventional method. In the figure, 1 and 1a are the main body of the device, 2 is a setting switch, 3 is a connection part, 4 is a connector, 5.5a is a numeric keyboard 1, 6 is a connection cable, 7 is a decoder, 8 is a data selector, 9. ~912 is Dio-1゛, 101~1
01. indicates the gies inch. Room 1 5d /, a

Claims (1)

[Claims] In an input device comprising a keyboard provided with a matrix of key contacts, which is detachably connected to a control unit, a conduction means is provided for bringing at least one of the matrix of key contacts into a connected state, and the control unit A keyboard connection detection method, characterized in that the presence or absence of a keyboard connection is determined based on the conduction state of a key contact point provided with a means.